Lomita City Council
October 7, 2025

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *492
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-127
sewer must either be removed from the system or become subject to an NPDES permit.” (55 Fed.Reg. 47990, 47995.)
In its 1990 rulemaking, U.S. EPA explained that the illicit discharge detection and elimination program requirement was intended to begin to implement the Clean Water Act’s provision requiring permits to “effectively prohibit non-stormwater discharges,” indicating that the illicit discharge detection and elimination program requirement did not constitute the full manifestation of this provision (55 Fed.Reg. 47990, 47995; see also 40 CFR § 122.26(d)(2)(i).)
U.S. EPA’s preamble to its 1990 Phase I MS4 regulations explain that the “effective prohibition” means that non-stormwater discharges to MS4s require separate NPDES permits, and that such permits must meet applicable requirements of CWA sections 402 and 301, including water quality-based requirements. 115 In response
to public comments suggesting that certain types of non-stormwater discharges should not be prohibited in such a manner because they did not pose significant environmental problems, U.S. EPA stated that “[it] disagrees that the above described flows will not pose, in every case, significant environmental problems.” U.S. EPA goes on to state that “[it] is clarifying that section 402(p)(3)(B) of the CWA (which requires permits for municipal separate storm sewers to 'effectively' prohibit non-storm water discharges) does not require permits for municipalities to prohibit certain discharges or flows of non-storm water to waters of the United States through municipal separate storm sewers in all cases.”116 U.S. EPA clarified that the permitting authority (i.e., the Los Angles Water Board here) “may include permit conditions that either require municipalities to prohibit or otherwise control any of these types of discharges where appropriate.”117 In addition, U.S. EPA’s MS4 Permit Improvement Guide includes the following example of MS4 permit language addressing the Permittee’s authority to require compliance by Dischargers:
“Authority to Require Compliance – Require compliance with conditions in the permittee’s ordinances, permits, contracts, or orders (i.e., hold dischargers accountable for their contributions of pollutants and flows).”118 Notably, the alternative to conditional exemptions to discharge prohibitions in the Order is a conservative interpretation of CWA section 402(p)(3)(B)(ii), which is to require Permittees to effectively prohibit all non-stormwater discharges. However, this alternative is more stringent than that provided in the Order (and previous permits) and, Permittees may incur more costs to implement a prohibition of all non-stormwater discharges than to implement or ensure implementation of specified BMPs to address non-stormwater discharges that are conditionally exempt from the discharge prohibition. An example of this is implementing an effective prohibition of landscape irrigation runoff as compared to implementing a local ordinance addressing landscape irrigation efficiency along with public outreach regarding use of drought tolerant landscaping and integrated pest management to minimize landscape irrigation runoff and associated pollutants.

4. Implementation of the Effective Prohibition on Non-Stormwater Discharges Consistent with previous MS4 permits, Part III.A of the Order requires each Permittee, for the portion of the MS4 for which it is an owner or operator, to prohibit 115 Id., at p. 48036-48037.
116 Id., at p. 48037.
117 Id., at p. 48037.
118 U.S. EPA. MS4 Improvement Guide (2010), p. 11.

EXHIBIT A
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MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-128
non-stormwater discharges through the MS4 to receiving waters except where such discharges are specifically authorized or conditionally exempt. For nearly two decades, some permittees have raised concerns with the Los Angeles Water Board’s use of “through the MS4” or similar language, alleging that the Los Angeles Water Board can only prohibit or regulate non-stormwater discharges “into” the MS4 and not “from” the MS4. The Los Angeles Water Board once again concludes that its usage of “through the MS4” is appropriate to implement the CWA’s effective prohibition of non-stormwater discharges.

U.S. EPA regulations and its 1990 preamble to the Phase I MS4 regulations use the terms “into,” “to,” “through,” and “from” the MS4 interchangeably when describing the federal requirement to effectively prohibit non-stormwater discharges. As noted previously, federal regulations define illicit discharges as “any discharge to a municipal separate storm sewer that is not composed entirely of storm water except discharges pursuant to a NPDES permit…”.119 U.S. EPA in its 1990 preamble states that “[t]hese [MS4] permits are to…effectively prohibit nonstorm water discharges to the municipal separate storm sewer system,” and that “[t]oday’s rule defines the term ‘illicit discharge’ to describe any discharge through a municipal separate storm sewer that is not composed entirely of storm water and that is not covered by an NPDES permit. Such illicit discharges are not authorized under the CWA. Section 402(p)(3)(B) of the CWA requires that permits for discharges from municipal separate storm sewers require the municipality to ‘effectively prohibit’ non-storm water discharges from the municipal separate storm sewer… Ultimately, such non-storm water discharges through a municipal separate storm sewer must either be removed from the system or become subject to an NPDES permit.”120 Further on, U.S. EPA states that “[t]he CWA prohibits the point source discharge of non-storm water not subject to an NPDES permit through municipal separate storm sewers to waters of the United States.”121 In addressing comments related to various types of non-stormwater discharges, U.S. EPA again uses “through” to describe the nature of the non-stormwater discharge prohibition, stating with regard to street wash waters that “such discharges…must be addressed by municipal management programs as part of the prohibition on nonstorm water discharges through municipal separate storm sewer systems.”122 Congress’ intent and U.S. EPA’s phraseology in its own regulations therefore support the Los Angeles Water Board’s interpretation that there is no meaningful difference with these terms, and that permittees must have adequate legal authority to control non-stormwater discharges into and from a portion of an MS4 for which it is an owner or operator.

When commenting on a draft version of the 2012 Los Angeles County MS4 Permit, U.S. EPA supported the non-stormwater discharge prohibition, which has been carried over in this Regional MS4 Permit. U.S. EPA stated:

We understand that concerns have been raised specifically on Section Ill.A.1 of the draft permit which requires that the permittee prohibit certain non-stormwater discharges “through” the MS4 while Section 402(p)(3)(B)(ii) of the Clean Water Act requires that the permittee prohibit discharges “into” the MS4. We support the Board’s proposed language 119 40 CFR § 122.26(b)(2).
120 55 Fed. Reg. 47990, 47995 (Nov. 16, 1990).
121 Id., at p. 47996.
122 Id., at p. 47990, 47996.

EXHIBIT A
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on this issue. We would note that the preamble to EPA’s 1990 stormwater regulations (55 FR 47995) itself uses the word “through” in describing the discharges which are to be prohibited. We believe this is in recognition of the fact that a discharge “into” the MS4 is tantamount to a discharge “through” the MS4 to receiving waters since the principal purpose of an MS4 is conveyance of water.123
Furthermore, the Los Angeles County Superior Court upheld the language in the 2001 Los Angeles County MS4 Permit and rejected the “into” versus “from” argument where the court stated:
[A]lthough this Court recognizes that it may not always be possible to prevent something from going into the system, it probably is the cheapest method. If something does not go in, then there is no concern about it coming out the other end. If the contaminant does not enter the system, there is no need to process it at the end of the system.124
The court further stated that the permit’s “regulation of what goes ‘into’ the storm drain does not take away from the [Permittees’] rights and needs to control the process” and set regional controls.125
Additionally, in Order WQ 2015-0075, the State Water Board agreed with the Los Angeles Water Board and found “the variation in language to be a distinction without a difference.” It concluded “[w]hether the Los Angeles MS4 Order prohibits non-storm water discharges into the MS4 or through the MS4 to receiving waters, the intent and effect of the prohibition is to prevent non-exempt non-storm water discharges from reaching the receiving waters. The legal standard governing nonstorm water – effective prohibition – is not altered because the Los Angeles MS4 Order imposes the prohibition at the point of entry into the receiving water rather than the point of entry into the MS4 itself. Instructively, U.S. EPA has used the terms “into,” “from,” and “through” interchangeably when describing the prohibition.” 126

5. Authorized and Conditionally Exempt Non-Stormwater Discharges The Order carries over provisions from previous permits exempting a limited number of authorized and conditionally exempt non-stormwater discharges from the discharge prohibition. Authorized non-stormwater discharges are those that are separately regulated by an individual or general NPDES permit, or by WDRs or a conditional waiver of WDRs for non-stormwater discharges from agricultural lands.

The conditionally exempt non-stormwater discharges are only exempt provided the discharge complies with the conditions set forth in the Order. In general, these conditions require Permittees to implement, or ensure that a discharger if not a named Permittee in the Order implements, BMPs to ensure that the nonstormwater discharges are not a source of pollutants to waters of the United States.

Conditions established in the Order for each of the non-stormwater discharge 123 U.S. EPA Comments on Draft MS4 Permit for Los Angeles County (July 23, 2012). 124 In re Los Angeles County Municipal Storm Water Permit Litigation (Sup. Ct. Los Angeles County, March 24, 2005, Case No. BS 080548), Statement of Decision from Phase I Trial on Petitions for Writ of Mandate.
125 Id., at p. 17.
126 State Water Board Order WQ 2015-0075, p. 61.

EXHIBIT A
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MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-130
categories ensure the protection of receiving water quality and are considered common practices.

The list of authorized and conditionally exempt non-stormwater discharges is similar, but not identical, to the previous permits. The Order conforms the exemptions for Ventura County, Los Angeles County, and the City of Long Beach and most closely matches provisions in the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit. The primary changes are as follows:
• The Order carries over the 2010 Ventura County MS4 Permit’s exemption for discharges from irrigated agriculture covered by WDRs or a conditional waiver of WDRs;
• The Order carries over the 2014 City of Long Beach MS4 Permit’s exemption for short-term releases of potable water with no dyes or additives for filming purposes;
• The Order removes references to U.S. EPA from the exemption for temporary non-stormwater discharges authorized pursuant to section 104(a) or 104(b) of CERCLA because the federal response authorities in these sections has been delegated to a number of federal agencies including, but not limited to, U.S.

EPA. For example, the Department of Defense, the Department of the Interior, and the Department of Transportation are all delegated with these federal response authorities;
• The Order does not carry over usage of the term “flows incidental to urban activities” from the 2010 Ventura County MS4 Permit to describe certain conditionally exempt discharges. Although the terminology is different, the categories of conditionally exempt discharges are the largely the same, except as described below.
• The Order eliminates the conditional exemptions in the 2010 Ventura County MS4 Permit for air conditioning condensate because the Los Angeles Water Board determined that these discharges were more appropriately regulated under a general permit. NPDES Permit No. CAG994003, Discharges of Nonprocess Wastewater to Surface Waters in Coastal Watershed of Los Angeles and Ventura Counties, was most recently reissued in 2014. • The Order eliminates the conditional exemptions in the 2010 Ventura County MS4 Permit for gravity flows from foundation, footing, and crawl space drains because the Los Angeles Water Board determined that these discharges were more appropriately regulated under a general permit. NDPES Permit No.

CAG994004, Discharges of Groundwater from Construction and Project Dewatering to Surface Waters in Coastal Watersheds of Los Angeles and Ventura Counties, was most recently reissued in 2018.
• The Order eliminates the non-stormwater action levels (NALs) included in the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit. These NALs had been included as a means to identify the potential need for additional controls for non-stormwater discharges in the future. The inclusion of NALs is redundant with other permit requirements such as the nonstormwater discharge prohibition and WQBELs for non-stormwater discharges.

EXHIBIT A
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MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-131

6. Specific Provisions
Part III.A.2.a-e (Non-Stormwater Discharges Not Subject to Discharge Prohibition). These provisions identify the types of non-stormwater discharges that are not subject to the discharge prohibition. The intent of this provision is to exempt certain non-stormwater discharges through the MS4 because they are separately regulated by another NPDES permit or permit equivalent, they are emergency discharges, or they are natural flows. The State Water Board and Los Angeles Water Board general NPDES permits that are used to regulate authorized non-stormwater discharges that are routinely discharged through the MS4 are, for the most part, listed in Table F-22 below.

Table F-22. General NPDES Permits, WDRs and Conditional Waivers Applicable to Non-Stormwater Discharges
127 Discharges of ground water from construction and project dewatering include treated or untreated wastewater from permanent or temporary construction dewatering operations; ground water pumped as an aid in the containment and/or cleanup of a contaminant plume; ground water extracted during shortterm and long-term pumping/aquifer tests; ground water generated from well drilling, construction or development and purging of wells; equipment decontamination water; subterranean seepage dewatering; incidental collected stormwater from basements; and other process and non-process wastewater discharges that meet the eligibility criteria and could not be covered under another specific general NPDES permit.
128 Low threat hydrostatic test water means discharges resulting from the hydrostatic testing or structural integrity testing of pipes, tanks, or any storage vessels using domestic water or from the repair and maintenance of pipes, tanks, or reservoirs.

NPDES Permit No. or Order No. Applicable Types of Discharges NPDES Permit No. CAG994003 –
Discharges of Nonprocess Wastewater to
Surface Waters in Coastal Watersheds of
Los Angeles and Ventura Counties
• Ground water seepage
• Uncontaminated pumped ground water
• Gravity flow from foundation drains,
footing drains, and crawl space pumps
• Air conditioning condensate
• Discharges of cleaning wastewater and
filter backwash
NPDES Permit No. CAG994004 –
Discharges of Groundwater from
Construction and Project Dewatering to
Surface Waters in Coastal Watersheds of
Los Angeles and Ventura Counties
• Uncontaminated pumped ground water
• Discharges from activities that occur at
wellheads, such as well construction, well
development (e.g., aquifer pumping tests,
well purging), or major well maintenance
• Gravity flow from foundation drains,
footing drains, and crawl space pumps
• Discharges of ground water from
construction and project dewatering127
NPDES Permit No. CAG990002 –
Discharges from Utility Vaults and
Underground Structures to Surface Waters
• Uncontaminated pumped ground water
• Gravity flow from foundation drains,
footing drains, and crawl space pumps
NPDES Permit No. CAG674001 –
Discharges from Hydrostatic Test Water to
Surface Waters in Coastal Watersheds of
Los Angeles and Ventura Counties
• Discharges of low threat hydrostatic test
water128

EXHIBIT A
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LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-132
129 Discharges covered by this permit include discharges from drinking water systems generated during the following activities: ground water supply well flushing or pump-to-waste; ground water well development, rehabilitation, and testing; ground water monitoring for purpose of supply well development, rehabilitation and testing; trench dewatering of drinking water during planned repairs; transmission system installation, cleaning, and testing; water treatment plant operations (excluding filter backwash that is discharged to a water of the U.S.); distribution system storage tank or reservoir releases; distribution system dewatering, flushing, and pressure testing; fire flow / fire hydrant testing; meter testing; automated water analyzers operations; pressure relief valves; and unscheduled activities that must be undertaken to comply with mandates of the Federal Drinking Water Act and California Health and Safety Code.

NPDES Permit No. CAG914001 –
Discharges of Treated Groundwater from
Investigation and/or Cleanup of Volatile
Organic Compounds Contaminated-Sites to
Surface Waters in Coastal Watersheds of
Los Angeles and Ventura Counties
• Discharges of treated ground water from
investigation and/or cleanup of volatile
organic compound (VOC) contaminated
sites
NPDES Permit No. CAG834001 –
Discharges of Treated Groundwater and
Other Wastewaters from Investigation and/or
Cleanup of Petroleum Fuel-Contaminated
Sites to Surface Waters in Coastal
Watersheds of Los Angeles and Ventura
Counties
• Discharges of treated groundwater and
other wastewaters from investigation
and/or cleanup of petroleum fuel-related
contamination arising from current and
former leaking underground storage tank
sites or similar operations
NPDES Permit No. CAG994006 –
Discharges of Groundwater from San Gabriel
Valley Groundwater Basin to Surface Water
in the Upper San Gabriel River and Rio
Hondo Watersheds – Los Angeles County
• Discharges from well startup operations
and testing of groundwater treatment
facilities in the San Gabriel Valley
watersheds
NPDES Permit No. CAG140001 – Drinking
Water System Discharges to Waters of the
U.S.
• Discharges from drinking water
systems129
NPDES Permit No. CAG990004 – Biological
and Residual Pesticide Discharges from
Vector Control Applications
• Discharges of residual pesticides from the
application of minimal risk pesticides,
which are pesticides that USEPA has
exempted from FIFRA requirements
when used only in the manner specified
in 40 CFR section 152.25, including
residuals from larvicides and adulticides
that are currently registered in California
and minimum risk pesticide products.

NPDES Permit No. CAG990005 – Residual
Aquatic Pesticide Discharges to Waters of
the United States from Algae and Aquatic
Weed Control Applications
• Discharges of residues resulting from
pesticide applications using products
registered for use in California containing
2,4-D, acrolein, copper, diquat, endothall,
fluridone, glyphosate, imazamox,
imazapyr, penoxsulam, sodium carbonate
peroxyhydrate, and triclopyr-based
algaecides and aquatic herbicides, and
adjuvants containing ingredients

EXHIBIT A
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ATTACHMENT F – FACT SHEET F-133
The Order also exempts temporary non-stormwater discharges authorized pursuant to sections 104(a) or 104(b) of the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). These discharges typically consist of short-term, high volume discharges resulting from the development or redevelopment of groundwater extraction wells, or federal or State-required compliance testing of potable water treatment plants, as part of a groundwater remediation action authorized under CERCLA. These discharges through the MS4 are only authorized if: (i) the discharge will comply with water quality standards identified as applicable or relevant and appropriate requirements (“ARARs”) under section 121(d)(2) of CERCLA; or (ii) the discharge is subject to either (a) a written waiver of ARARs pursuant to section 121(d)(4) of CERCLA or (b) a written determination that compliance with ARARs is not practicable considering the exigencies of the situation, pursuant to 40 CFR section 300.415(j). Exempting these discharges is appropriate because, as noted above, the discharges must comply with water quality standards, which are identified as ARARs, or must be subject to a written waiver of ARARs based on one or more factors identified in 42 U.S.C § 9621(d)(2) or determination that compliance with ARARs is not practicable given the urgency of the situation and scope of the action among other factors.

Additionally, a decision to authorize a discharge through the MS4 to surface waters will not be made by U.S. EPA or another federal agency without first conducting a comprehensive evaluation of containment, treatment, reinjection, or re-use options for the water generated from the subject wells. If a decision to discharge through the MS4 is made, such authorization of the discharge under CERCLA will require that the discharger shall:
a. Implement BMPs to minimize the rate and duration of the discharge and remove excessive solids and implement other on-site physical treatment where feasible;
i. Promote infiltration of discharged water in locations that will prevent or minimize degradation of groundwater quality;
ii. Notify the affected MS4 Permittees, including Ventura County Watershed Protection District and Los Angeles County Flood Control District, and the MS4 Permittee with land use authority over the discharge location, and the Los Angeles Water Board at least one week prior to a planned discharge (unless U.S. EPA determines in writing that exigent circumstances require a shorter notice period) and as soon as possible (but no later than 24 hours after the discharge has occurred) for unplanned discharges;
represented by the surrogate
nonylphenol.

Order No. R4-2016-0143 – Conditional
Waiver for Discharges from Irrigated Lands
• Discharges from irrigated agricultural
lands, including lands planted for row,
vineyard, pasture, field and tree crops,
nurseries, nursery stock production,
wholesale nurseries, and greenhouse
operations with permeable floors, which
are not subject to WDRs, including a MS4
permit or other NPDES permit

EXHIBIT A
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iii. Monitor any pollutants of concern in the discharge; 130 and
iv. Maintain records for all discharges greater than 100,000 gallons. 131
The Order continues to unconditionally exempt non-stormwater discharges from emergency firefighting activities (i.e., flows necessary for the protection of life or property) from the discharge prohibition. Discharges from vehicle washing of firefighting vehicles, building fire suppression system maintenance and testing (e.g., sprinkler line flushing), fire hydrant maintenance and testing, and other routine maintenance activities are not considered emergency firefighting activities.

Additionally, the Order distinguishes between emergency and non-emergency firefighting flows. Essential non-emergency firefighting flows are still eligible for a conditional exemption as discussed below.

Natural flows not subject to the non-stormwater discharge prohibition in the Order include natural springs, flows from riparian habitats and wetlands, diverted stream flows authorized by the State Water Board or the Los Angeles Water Board, uncontaminated groundwater infiltration, and rising groundwater where groundwater seepage is not otherwise covered by a NPDES permit. These discharges are not considered a potential source of pollutants.

Part III.A.3.(a-b) (Conditionally Exempt Non-Stormwater Discharges). These provisions identify the types of non-stormwater discharges that are conditionally exempt from the discharge prohibition. For non-stormwater discharges to be conditionally exempt from the discharge prohibition, the Permittees must identify appropriate BMPs, monitor and report on the non-stormwater discharges where applicable, and ensure implementation of effective control measures as discussed in subpart 7 below.

The Order separately identifies flows from non-emergency firefighting activities, discharges from drinking water supplier distribution systems, and potable wash water used to clean reservoir covers as “conditionally exempt essential” nonstormwater discharges rather than combining them into the same category as the other conditionally exempt non-stormwater discharges. In doing so, the Los Angeles Water Board recognizes that these discharges are essential public service discharge activities and are directly or indirectly required by other state or federal statutes and/or regulations as done in the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit. Note that the 2010 Ventura County MS4 Permit had an exemption for flows from firefighting activities but did not include a category for discharges from drinking water supplier distribution systems.

Additionally, consistent with the California Ocean Plan, the Order imposes 130 Pollutants of concern include, at a minimum, trash and debris, including organic matter, TSS, any pollutant being addressed by the groundwater remediation action under CERCLA, and any pollutant for which there is a Water Quality Based Effluent Limitation in Part IV of the Order applicable to discharges from the MS4 to the receiving water.
131 Records shall be maintained, as appropriate, on the: name of CERCLA authorized discharger, date and time of notification (for planned discharges), method of notification, location of discharge, discharge pathway, receiving water, date of discharge, time of the beginning and end of the discharge, duration of the discharge, flow rate or velocity, estimated total number of gallons discharged, type of pollutant removal equipment used, type of dechlorination equipment used if applicable, type of dechlorination chemicals used if applicable, concentration of residual chlorine if applicable, type(s) of sediment controls used, and field and laboratory monitoring data. Records shall be retained for three years, unless the Los Angeles Water Board requests a longer record retention period and shall be made available upon request by the MS4 Permittee or the Los Angeles Water Board.

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additional requirements on conditionally exempt non-stormwater discharges for direct discharges to Areas of Special Biological Significance (ASBS).

If any of the conditionally exempt non-stormwater discharges are identified as being a potential source of pollutants, the Order contains a provision that the Los Angeles Water Board, based on an evaluation of monitoring data and other relevant information including TMDLs and antidegradation policies, may require that a discharger obtain coverage under a separate individual or general State Water Board or Los Angeles Water Board NPDES permit for the non-stormwater discharge or may require that the Permittee ensures that the discharger implements additional conditions specified or approved by the Executive Officer to ensure that the discharge is not a source of pollutants.

7. BMPs for Non-Stormwater Discharges
To eliminate adverse impacts from conditionally exempt non-stormwater discharges, Permittees are required to implement appropriate BMPs, or ensure that a discharger not named as a Permittee in the Order implements appropriate BMPs consistent with the requirements in Part III.A.5 of the Order. The Order contains language carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit that specifies certain conditions, including implementation of BMPs, for each category of conditionally exempt nonstormwater discharge that must be met in order for the non-stormwater discharge to be exempted from the non-stormwater discharge prohibition and thus allowed through the MS4. The 2010 Ventura County MS4 Permit also included similar conditions. The intent of these provisions is to ensure that Permittees implement BMPs consistent with common practice. The Los Angeles Water Board has included applicable guidance documents where appropriate.

One such example is that Permittees must develop and implement procedures to ensure that drinking water system owners/operators drinking water system owners/operators that may discharge amounts greater than 100,000 gallons to the Permittee’s MS4: (1) provide notification at least 72 hours prior to a planned discharge and as soon as possible after an unplanned discharge; (2) monitor any pollutants of concern in the drinking water system discharge; (3) keep records; and (4) implement appropriate BMPs based on the American Water Works Association (California-Nevada Section) Guidelines for the Development of Your Best Management Practices (BMP) Manual for Drinking Water System Releases (2005) or equivalent industry standard BMP manual.

The Statewide Recycled Water Policy, adopted by the State Water Board through Resolution No. 2009-0011, and amended by Resolution No. 2013-0003 and Resolution No. 2018-0057, encourages the safe use of recycled water from wastewater sources that meets the definition in California Water Code section 13050(n), in a manner that implements state and federal water quality laws and protects public health and the environment. The conditions for non-stormwater discharges related to landscape irrigation using potable water and landscape irrigation using reclaimed water were carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit and emphasize the control of incidental runoff from landscape irrigation. Consistent with the Recycled Water Policy, the BMPs incorporated into the Order for potable landscape irrigation ensure that water is conserved, overspray and over irrigation

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causing incidental runoff is minimized, and exposure to landscape related pollutants is minimized.

State Water Board Water Quality Order No. 2009-0006-DWQ, General Waste Discharge Requirements for Landscape Irrigation Uses of Municipal Recycled Water, is a general permit for producers and distributors of recycled water for landscape irrigation uses. As part of that general permit, the producers and distributors of recycled water for landscape irrigation are required to develop an Operations and Maintenance Plan (O&M Plan) that includes an Operations Plan and an Irrigation Management Plan. Therefore, any landscape irrigation discharges of reclaimed wastewater to the MS4 must comply with the relevant portion of the O&M Plan including the Irrigation Management Plan. By explicitly referencing the O&M requirement in that general permit, it centralizes the requirements for landscape irrigation using reclaimed wastewater and helps to ensure that procedures are in place for conserving water, minimizing incidental runoff, and minimizing exposure to landscape related pollutants.

Non-stormwater discharge provisions have been carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit for the dewatering of lakes to the MS4. The provisions for the dewatering of lakes including removing and legally disposing of all visible trash on the shoreline or on the surface of the lake and the cleaning of the MS4 inlet and outlet where the water will be discharged to the receiving water have been consistently incorporated into Los Angeles Water Board authorizations to discharge non-stormwater from lakes, reservoirs, and ponds. In addition, provisions for volumetrically and velocity controlling discharges as well as taking measurements to stabilize lake bottom sediments are carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit to the Order to ensure that turbidity in receiving waters due to the discharge is minimized. The permit provisions for the dewatering of lakes ensure the protection of receiving water quality.

Consistent with the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit, Basin Plan requirements for residual chlorine have been explicitly included in the conditions for drinking water supplier distribution system releases, dechlorinated/debrominated swimming pool/spa discharges, and dewatering of decorative fountains.132
Specific BMPs for discharges from swimming pools/spas and the dewatering of decorative fountains have been carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit to the Order, including prohibiting the dewatering of swimming pools/spas or decorative fountains containing copper-based algaecides and requiring the implementation of controls to prevent introduction of pollutants prior to discharge. Swimming pool/spa discharges and decorative fountain water must be dechlorinated or debrominated using holding time, aeration, and/or sodium thiosulfate and if necessary, shall be pH adjusted to within the range of 6.5 and 8.5. The MS4 inlet and outlet must be inspected and cleaned out immediately prior to discharge to protect receiving water 132 Swimming pool discharges explicitly excludes discharges of cleaning wastewater and filter backwash.

However, these discharges are considered exempt non-stormwater discharges if the discharge meets the eligibility requirements and obtains coverage under the Los Angeles Water Board’s general permit for discharges of nonprocess wastewater to surface waters in coastal watersheds of Los Angeles and Ventura counties (NPDES Permit No. CAG994003).

EXHIBIT A
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quality. In addition, provisions for volumetrically and velocity controlling discharges are carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit to the Order to ensure that turbidity in receiving waters due to the discharge is minimized.

In addition to the specific inclusion of the Basin Plan water quality objective for residual chlorine, the Order allows discharges of drinking water supplier distribution system releases as long as specified BMPs are implemented. BMPs must be implemented to prevent introduction of pollutants to drinking water supplier distribution system releases prior to discharge to the receiving water. BMPs must be consistent with the American Water Works Association (California – Nevada Section) BMP Manual for Drinking Water System Releases or other equivalent industry standard BMP manual. This requirement therefore gives Permittees flexibility to design their own program by choosing their BMP manual to address non-stormwater discharges from drinking water supplier distribution systems.

Similar to discharges from swimming pools/spas and dewatering of decorative fountains, drinking water supplier distribution system releases must be dechlorinated or debrominated using holding time, aeration, and/or sodium thiosulfate and if necessary, shall be pH adjusted to within the range of 6.5 and

8.5. The MS4 inlet and outlet must be inspected and cleaned out immediately prior to discharge to protect receiving water quality. BMPs such as sandbags or gravel bags, or other appropriate means shall be utilized to prevent sediment transport and all sediment shall be collected and disposed of in a legal and appropriate manner. Additional provisions for volumetrically and velocity controlling discharges are carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 permit to the Regional MS4 Permit to ensure that turbidity in receiving waters due to the discharge is minimized. The permit provisions for drinking water supply and distribution system releases, dechlorinated/ debrominated swimming pool/spa discharges, and dewatering of decorative fountains ensures the protection of receiving water quality.

Potable wash water used to clean reservoir covers is included in the Order as a conditionally exempt non-essential non-stormwater discharge. This requirement and the corresponding BMPs were carried over from the 2014 City of Long Beach MS4 Permit. Provisions and BMPs for potable wash water used to clean reservoir covers is pursuant to The Final Long Term 2 Enhanced Surface Water Treatment Rule (EPA 815-R06-005 February 2006), which includes requirements for “Systems that store treated water in open reservoirs [where the systems] must either cover the reservoir or treat the reservoir discharge to inactivate 4-log virus, 3-log Giardia lamblia, and 2-log Cryptosporidium.”133 The provisions and BMPs are also pursuant to the Safe Drinking Water Act (SDWA).

The Los Angeles Water Board evaluated and established a list of approved BMPs for various programs and activities through Los Angeles Water Board Resolution 98-08 that serves as appropriate BMPs for inclusion in the discharger and Permittees’ regulatory programs. Requirements for street/sidewalk wash water contained in Resolution 98-08 have been explicitly incorporated into the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit and 133 U.S. EPA. Fact Sheet - Long Term 2 Enhanced Surface Water Treatment Rule. December 2005. EPA 815-F-05-009.

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have been carried over to the Order. The inclusion of the requirements originally identified in Resolution 98-08 ensures the protection of receiving water quality.

Specific BMPs for discharges from non-commercial car washing have been carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit to the Order to prevent the introduction of pollutants prior to discharge. BMPs that must be implemented for the discharge of non-commercial vehicle wash water include minimizing the amount of water used by turning off nozzles or kinking the hose when not spraying a vehicle and by using a low-volume pressure washer; using biodegradable, phosphate free detergents and non-toxic cleaning products; where possible, washing vehicles on permeable surfaces where wash water can percolate into the ground; creating a temporary berm or block off the storm drains; using pumps or vacuums to direct water to pervious areas; and emptying buckets of soapy water or rinse water into the sanitary sewer system.

These BMPs are common practice and ensure the protection of receiving water quality.

Discharges resulting from essential non-emergency firefighting activities have been carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit to the Order. Similar BMPs have been incorporated into other California MS4 permits. For example, both the Riverside County and Orange County MS4 permits require the development and implementation of a program to address pollutants from non-emergency firefighting flows. Rather than develop a program to address non-emergency firefighting discharges, Permittees may implement the BMPs contained in the Best Management Practices Plan for Urban Runoff Management for Participating Riverside County Fire Fighting Agencies or an equivalent guidance manual.

The inclusion of specific conditions for conditionally exempted non-stormwater discharges in the Order centralizes the requirements for non-stormwater discharges. Conditions established in the Order for each of the conditionally exempt non-stormwater discharge categories are common practice and have been incorporated into other area MS4 permits.

8. Permittee Requirements for Non-Stormwater Discharges The Order includes specific requirements for Permittees related to targeted screening of MS4 outfalls for non-stormwater discharges, and monitoring and evaluation of significant non-stormwater discharges. Permittees are required to develop and implement procedures to ensure that all conditions required for conditionally exempt non-stormwater discharges are being implemented. These requirements were carried over from the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit to help clarify the responsibilities of the Permittees versus the responsibilities of the non-MS4 Permittee dischargers to the MS4. The development and implementation of these procedures helps to ensure compliance with the non-stormwater discharge prohibition and ensure that the non-stormwater discharges are not sources of pollutants.

9. Compliance Demonstration
A Permittee’s implementation of program elements and control measures to effectively eliminate prohibited non-stormwater discharges will be considered as evidence of whether a Permittee is complying with the non-stormwater discharge prohibition in Part III.A of the Order. Where a Permittee is fully implementing its

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Illicit Connections and Illicit Discharges Elimination Program, either pursuant to Part VIII.I of the Order, or by incorporation of customized actions into a WMP as approved by the Los Angeles Water Board (see Part IX.B of the Order), the Los Angeles Water Board would conduct a fact-specific analysis of the nature and source of the unauthorized non-stormwater discharge and the efforts of the Permittee to prohibit the discharge in support of any enforcement action under Part III.A of the Order.

B. Trash

1. Federal Requirements
Federal regulations identify the need to develop, implement, and enforce controls to reduce the discharge of pollutants from MS4s.134 Federal regulations further specify that Permittees must include in their management program maintenance activities and a maintenance schedule for structural controls to reduce pollutants (including floatables) in discharges from MS4s.135 The highlighting of floatables is pertinent since a significant portion of trash is characteristic of, and within the category of, floatable pollutants. Municipal trash management programs are discussed in federal documents including U.S. EPA’s Stormwater Menu of BMPs fact sheet on Trash and Debris Management.
136 This fact sheet highlights source
control and structural control techniques to manage trash.

2. Statewide Trash Amendments
On April 7, 2015, the State Water Board adopted Part 1 Trash Provisions (Trash Provisions) of the Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (ISWEBE Plan) and an amendment to the Ocean Plan to control trash. Together, these amendments are referred to as the Trash Amendments or Trash Provisions. The Trash Amendments establish a water quality objective, a prohibition on the discharge of trash, and implementation requirements to control trash. The Trash Amendments were approved by OAL on December 2, 2015 and by U.S. EPA on January 12, 2016.

3. Applicability
The Trash Amendments apply to all waters of the State, except waters in the Los Angeles Region in which a TMDL for trash was in effect prior to the effective date of the Trash Amendments.
137
134 40 CFR § 122.26(d)(2)(iv).
135 Id., subd. (d)(2)(iv)(A)(1).
136 U.S. EPA. Trash and Debris Management, Public Education and Outreach on Stormwater Impacts:

Education for Homeowners.
137 While the Trash Amendments do not apply to waters addressed by existing trash TMDLs in the Los Angeles Region, the Trash Amendments directed the Los Angeles Water Board to reconsider the scope of its trash TMDLs, except for the Los Angeles River Watershed and Ballona Creek Trash TMDLs, within one year of the Trash Amendments’ effective date. The Los Angeles Water Board held an initial public meeting to consider its trash TMDLs on November 28, 2016. On June 14, 2018 the Los Angeles Water Board adopted revisions to the Malibu Creek Watershed Trash TMDL and the Revolon Slough and Beardsley Wash Trash TMDL to align them with the Trash Amendments. On March 14, 2019 the Los Angeles Water Board adopted a resolution finding that the Santa Monica Bay Nearshore and Offshore Debris TMDL and the Machado Lake Trash TMDL could not be aligned with the Trash Amendments. On June 13, 2019 the Los Angeles Water Board adopted a resolution finding that the Ventura River Estuary

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The Order incorporates the Trash Amendments in all areas not addressed by an existing trash TMDL. For areas addressed by an existing trash TMDL, the Order requires Permittees to comply with the appropriate TMDL-based trash WQBELs specified in Part IV.B.3 of the Order.

4. Implementation
The Trash Amendments require NPDES permits regulating MS4 permittees with regulatory authority over priority land uses (PLUs) to include provisions to prohibit the discharge of trash in Waters of the United States. Permittees may elect to comply with the trash prohibition under one of two compliance tracks. Under Track 1, a Permittee must install, operate, and maintain full capture systems for storm drains that capture runoff from priority land uses in their respective jurisdictions.

Under Track 2, a Permittee must install, operate, and maintain any combination of full capture systems, multi-benefit projects, treatment controls and/or institutional controls. Permittees outside of or lacking land use authority over PLUs do not have to implement the trash prohibition unless directed to by the Los Angeles Water Board as described in the discussion of designated land use areas below.

Prior to the issuance of the Order, and as contemplated by the Trash Amendments, on August 18, 2017, the Los Angeles Water Board issued California Water Code Section 13383 Orders to Permittees whose jurisdictional areas are not fully addressed by an existing trash TMDL. These California Water Code Section 13383 Orders required Permittees to submit: (1) a letter identifying the Permittee’s selected compliance option (Track 1 or Track 2) to comply with the Trash Provisions by November 20, 2017; and (2) supporting documents based on the compliance option selected by February 18, 2019. The supporting documents for Permittees selecting Track 1 included the following. For Permittees selecting Track 1, a jurisdictional or watershed map(s) identifying 1) all PLU areas discharging to the storm drain network; 2) any drainage areas addressed by existing trash TMDLs; 3) the corresponding storm drain network; 4) proposed locations of all certified full capture systems; and 5) proposed equivalent alternative land uses, documentation demonstrating that the substitution of equivalent alternative land uses has been approved by the Los Angeles Water Board Executive Officer, and corresponding storm drainage network, if applicable. The supporting documents for Permittees selecting Track 2 generally included a jurisdictional map(s) identifying the provisions 1-3 mentioned above as well as locations or land uses where a combination of controls will be implemented to achieve full capture system equivalency (see Attachment A for a definition of this term) and an assessment of trash levels for all PLUs and for other selected locations or land uses within the MS4s jurisdiction if proposing to implement any combination of controls in locations other than PLUs. In addition, Permittees selecting Track 2 were also required to submit an implementation plan that included requirements similar to the ones included in Part III.B.2.b of the Order. Table F-23 below, lists the Permittees that were issued a California Water Code Section 13383 Order and the compliance option that they selected in response to the Order. The Table also notes those Permittees that are outside of or lack jurisdiction over PLUs. All Permittees that selected either of the Tracks, also submitted the required supporting documents that were due by February 18, 2019. Only two cities selected Track 2, the cities of Trash TMDL, Lake Elizabeth Trash TMDL, and Legg Lake Trash TMDL, could not be aligned with the Trash Amendments.

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Gardena and Los Angeles. On April 8, 2019, the Los Angeles Water Board sent a correspondence to Track 1 Permittees clarifying that they could proceed implementing the provisions of the 13383 Order without requiring further approval.

On June 26, 2019, the Los Angeles Water Board issued a conditional approval letter to the City of Gardena, requiring additional information and submittals in order to approve its implementation plan, which were due by March 31, 2021. In its implementation plan, the City of Los Angeles indicated that it is in compliance with the Trash Amendments; Board staff are in the process of reviewing the information provided by both cities.

Table F-23. Selected Compliance Option in Response to California Water Code Section 13383 Orders
Permittee
Selected Compliance
Option
(Track 1 or Track 2)
Arcadia Track 1
Artesia Track 1
Azusa Track 1
Baldwin Park Track 1
Bellflower Track 1
Bradbury Track 1
Carson Track 1
Cerritos Track 1
Claremont Track 1
Compton 138
County of Los Angeles Track 1
Covina Track 1
Diamond Bar Track 1
Downey Track 1
Duarte Track 1
El Monte Track 1
El Segundo Track 1
Gardena Track 2
Glendora Track 1
Hawaiian Gardens Track 1
Hawthorne Track 1
Industry Track 1
Inglewood Track 1
Irwindale Track 1
La Habra Heights Track 1
La Mirada Track 1
La Puente Track 1
La Verne Track 1
Lakewood Track 1
Lawndale Track 1
Lomita Track 1
138 On December 20, 2017, the City of Compton responded to the Los Angeles Water Board’s August 18, 2017’s 13383 Order and stated that the City is only subject to the Los Angeles River Watershed Trash TMDL. Board staff are still investigating the City’s claim.

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Permittee
Selected Compliance
Option
(Track 1 or Track 2)
Los Angeles Track 2
Los Angeles County Flood
Control District
139
Manhattan Beach Track 1
Monrovia Track 1
Norwalk Track 1
Paramount Track 1
Pico Rivera Track 1
Pomona Track 1
Rancho Palos Verdes Track 1
Redondo Beach Track 1
Rolling Hills 140
Rolling Hills Estates Track 1
San Dimas Track 1
Santa Clarita Track 1
Santa Fe Springs Track 1
Signal Hill Track 1
South El Monte Track 1
Torrance Track 1
Walnut Track 1
West Covina Track 1
Whittier Track 1
County of Ventura Track 1
Camarillo Track 1
Fillmore Track 1
Moorpark Track 1
Ojai Track 1
Oxnard Track 1
Port Hueneme Track 1
Santa Paula Track 1
Simi Valley Track 1
Thousand Oaks Track 1
Ventura Track 1
Ventura County Watershed
Protection District
141
Long Beach Track 1
Both compliance tracks focus trash control efforts on PLUs. PLUs are areas that have been shown to generate a significant amount of trash and include high density residential, industrial, commercial, mixed urban, and public transportation stations.

A compliance framework focused on PLUs allows MS4s to allocate trash-control resources to the highest priority areas.
139The District has no jurisdictional authority over PLUs. 140The City has no PLUs within its jurisdiction.
141The District has no jurisdictional authority over PLUs.

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In some cases, non-priority land use areas may also generate a substantial amount of trash. Permittees may get approval from the Los Angeles Water Board to substitute one or more of the PLUs with an alternate land use area that generates trash at rates equivalent or greater than the PLU(s) being substituted. The Los Angeles Water Board may also determine that a non-priority land use or location generates a substantial amount of trash. Where this determination is made, the Los Angeles Water Board may require Permittees to adopt Track 1 or Track 2 control measures over these areas. The Order refers to these areas as “designated land use areas.” No designated land use areas for trash have been identified as of the issuance of the Order.

5. Implementation Schedule
The Trash Amendments require NPDES permits for MS4 permittees to contain provisions prohibiting the discharge of trash within ten years of the effective date of the first implementing permit, or no later than fifteen years from the effective date of the Trash Amendments (December 2, 2030). The Order is the first implementing permit for the Permittees; therefore, the Permittees must obtain full compliance with the Trash Amendments by December 2, 2030. Additional time for compliance may be authorized for designated land uses identified after the effective date of the Order. In no case may the time for compliance with the Trash Amendments for newly Designated Land Uses be more than 10 years.

Part III.B.2 of the Order incorporates the Trash Amendments requirements for Permittees with regulatory authority over PLUs, designated land uses, or equivalent alternate land uses. Specifically, Part III.B.2.a of the Order outlines the compliance methods and allows Permittees to change their compliance method by submitting a written request to the Los Angeles Water Board for approval of a modified jurisdictional map. Permittees changing their compliance method to Track 2 are also required to submit an Implementation Plan. Part III.B.2.b of the Order outlines provisions for Implementation Plan for Track 2; and Part III.B.2.c of the Order outlines provisions for jurisdictional map. Part III.B.2.d of the Order establishes the implementation schedule for complying with the discharge prohibition consistent with the Trash Amendments. This provision establishes an interim compliance deadline requiring 50% of all PLUs and/or approved equivalent alternate land uses to meet full capture (Track 1) or full capture system equivalency (Track 2) within 5 years and a final compliance deadline requiring 100% of all PLUs and/or approved equivalent alternate land uses to meet full capture (Track 1) or full capture system equivalency (Track 2) by no later than 10 years from the effective date of the Order or December 2, 2030, whichever is sooner. For designated land uses, it may not be feasible to expect compliance within ten years from the effective date of the Order. Hence, the final compliance date for a designated land use is no longer than 10 years from the Los Angeles Water Board’s written determination to designate a land use or location as a designated land use.

6. Previous Permit Requirements
Part VI.D.9.h.vii of the 2012 Los Angeles County MS4 Permit and Part VII.L.8.vii of the 2014 City of Long Beach MS4 Permit required Permittees to install trash excluders, or equivalent devices, on or in catch basins or outfalls to prevent the discharge of trash to the MS4 or receiving water no later than December 28, 2016 and March 28, 2018, respectively. Part 4.G.I.5.(e) of the 2010 Ventura County MS4 Permit also required the Permittees to comply with the same requirements no later

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than July 8, 2012. This requirement only applied to areas not subject to a trash TMDL and identified as a “Priority A” area and did not apply to sites where the application of such BMP(s) alone would cause flooding. Priority A was defined as areas consistently generating the highest volumes of trash and/or debris.

Alternatively, Permittees could implement alternative or enhanced BMPs that provide substantially equivalent removal of trash. The Statewide Trash Amendments closely align with the intent and scope of the requirements of the previous permits. Therefore, incorporation of Statewide Trash Amendments into the Order are not new requirements but rather a refinement of the existing requirements.

V. RATIONALE FOR EFFLUENT LIMITATIONS AND DISCHARGE SPECIFICATIONS Clean Water Act section 402(p)(3)(B)(iii) requires MS4 permits to include “controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants.” The control of pollutants discharged is established through effluent limitations and other requirements in NPDES permits. The Clean Water Act generally requires NPDES permits to include technology-based effluent limitations and any more stringent water quality-based effluent limitations necessary to meet water quality standards.

Both types of limitations are in the Order and are discussed below.

A. Technology-Based Effluent Limitations
Section 301(b)(1)(A) of the CWA and 40 CFR section 122.44(a) require that NPDES permits include technology-based effluent limitations and standards. 142 In 1987, the
CWA was amended to require that municipal stormwater discharges “reduce the discharge of pollutants to the maximum extent practicable.” (CWA § 402(p)(3)(B)(iii).) The “maximum extent practicable” (MEP) standard is the applicable federal technologybased standard that MS4 owners and operators must attain to comply, in part, with their NPDES permits.143 40 CFR section 122.26(d)(2)(iv) further details the MEP standard, which requires that MS4 owners and operators implement comprehensive pollutant control measures in a stormwater management program including management practices, control techniques and system, design and engineering methods, and such other provisions which are appropriate. Permit requirements to implement the MEP standard are generally referred to, collectively, as best management practices or BMPs. 142 A technology-based effluent limitation is based on the capability of a model treatment method to reduce a pollutant to a certain concentration (NPDES Permit Writer’s Manual (September 2010), Appendix A).

Technology-based effluent limitations generally are expressed numerically as the maximum amount of pollutant that may be discharged (either as a prohibition or as a concentration or mass; mass is usually normalized either based on production units or wastewater flow) but are sometimes narrative effluent limitations such as model best management practices for an industrial category like “Concentrated Aquatic Animal Production.” For example, model best management practices are identified for solids control, including the following, “[i]n order to minimize the discharge of accumulated solids from settling ponds and basins and production systems, identify and implement procedures for routine cleaning …, and procedures to minimize any discharge of accumulated solids during the … harvesting of aquatic animals in the production system” (NPDES Writers’ Manual (September 2010), p. 5-33). Technologybased requirements represent the minimum level of control that must be imposed in a permit issued under CWA § 402.
143 Note that the MEP standard only applies to stormwater discharges from the MS4. Non-stormwater discharges are subject to a different standard – specifically, non-stormwater discharges through the MS4 must be effectively prohibited.

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Examples of BMPs used to comply with the MEP standard include street sweeping, requiring erosion controls at construction sites (e.g., straw wattles, silt fences), and catch basin cleanouts.

The fundamental requirement that municipalities reduce pollutants in municipal stormwater discharges to the MEP remains a cornerstone of the mandate imposed on municipalities by the federal Clean Water Act and implementing NPDES regulations.

Meeting the MEP standard is generally a result of emphasizing robust pollution prevention and control through various programs and structural measures. These pollution prevention and control methods require municipalities to take actions that will lessen the incidence of pollutants entering the storm drains by regulating the behavior and practices of the municipalities, their residents, and their businesses and controlling the discharge of pollutants through structural measures and treatment methods.

Neither Congress nor the U.S. EPA has specifically defined the term “maximum extent practicable.” Rather, the MEP standard is an ever evolving, flexible and advancing concept, which considers technical and economic feasibility. As knowledge and technology regarding controlling stormwater runoff continue to evolve, so too must the actions that are taken to comply with the standard. Congress established this flexible MEP standard so that administrative bodies would have “the tools to meet the fundamental goals of the Clean Water Act in the context of storm water pollution.”144 This standard was designed to allow permit writers flexibility to tailor permits to the sitespecific nature of MS4s and to use a combination of pollution controls that may be different in different permits.145 The MEP standard is also expected to evolve in light of programmatic improvements, new source control initiatives, and technological advances that serve to improve the overall effectiveness of stormwater management programs in reducing pollutant loading to receiving waters.

In addition to regulations, U.S. EPA has issued guidance documents that discuss the type of BMPs that should be included in MS4 permits in order to reduce the discharge of pollutants in stormwater to the MEP.146 Successive permits for the same MS4 must become more refined and detailed and require greater levels of specificity over time in defining what constitutes MEP, based on experience under the previous permit. For example, the 1990 Los Angeles County MS4 Permit provided a general requirement that Permittees develop and implement a plan with a schedule of implementation for BMPs to control pollutants from residential, commercial, and industrial sites to the MEP.

To continue to address these land use areas, the 1996 Permit required Permittees to develop and implement a model system for prioritization of development projects and establish a list of recommended BMPs in a model program, referred to as a Standard Urban Storm Water Mitigation Plan (SUSMP). For new and re-development, the 2001 Los Angeles County MS4 Permit established numeric criteria, requiring the control of a specific volume of runoff from these priority development and redevelopment projects, i.e., the 85th percentile, 24-hour storm volume. In the 2012 Los Angeles County MS4 Permit, Permittees were required to prioritize onsite retention of this runoff and, only if that was infeasible, to use other means (such as flow-through treatment) of controlling that runoff volume. The 1994 Ventura County MS4 Permit provided a general 144 Building Industry Ass’n of San Diego County v. State Water Resources Control Board (2004) 124 Cal.App.4th 866, 884.
145 In re City of Irving, Texas, Municipal Storm Sewer System (July 16, 2001) 10 E.A.D. 111 (E.P.A.), *6. 146 See, e.g., U.S. EPA, MS4 Permit Improvement Guide (2010). Prior to issuance of the MS4 Permit Improvement Guide, U.S. EPA provided BMP “menus” for the required elements of a MS4 permittee’s stormwater management program as required by 40 CFR § 122.26(d)(2)(iv).

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requirement that Permittees develop and implement source control BMPs and treatment control BMPs in the areas of land development, industrial, commercial, and construction sites. The 2000 Ventura County MS4 Permit required Permittees to develop and implement a comprehensive stormwater quality management program to reduce the discharge of stormwater pollutants to the MEP. In the 2010 Ventura County MS4 Permit, Permittees were required to implement LID strategies for new development and redevelopment, which would maintain pre-development hydrology and utilize natural controls to reduce stormwater pollution. This is consistent with U.S. EPA’s intent that stormwater management programs evolve based on changing conditions from program development and implementation and corresponding improvements in water quality.147 There is ample evidence of this evolution in stormwater management. Examples include the development of full capture trash control devices in response to the Los Angeles Region Trash TMDLs, innovative media filters for use in outfalls at the Boeing Santa Susana Field Laboratory that have potential municipal applications; and regional scale multi-benefit stormwater capture projects such as the Carriage Crest Park project, which captures stormwater from an 1,146-acre, multi-jurisdictional drainage area for treatment and reclamation at the adjacent wastewater treatment facility.

To provide clarification to the Regional Water Boards, the State Water Board’s Office of Chief Counsel issued a memorandum dated February 11, 1993 regarding the “Definition of ‘Maximum Extent Practicable’.” In the memorandum, the State Water Board interpreted the MEP standard to entail “a serious attempt to comply,” and that under the MEP standard, “practical solutions may not be lightly rejected.” The memorandum states, “[i]n selecting BMPs which will achieve MEP, it is important to remember that municipalities will be responsible to reduce the discharge of pollutants in storm water to the maximum extent practicable. This means choosing effective BMPs, and rejecting applicable BMPs only where other effective BMPs will serve the same purpose, the BMPs would not be technically feasible, or the cost would be prohibitive.” The memorandum suggests several factors to be considered when choosing BMPs, including effectiveness, regulatory compliance, public acceptance, cost, and technical feasibility. The memorandum further states that, “[a]fter selecting a menu of BMPs, it is of course the responsibility of the discharger to insure that all BMPs are implemented.” The Order includes programmatic requirements in six areas pursuant to 40 CFR section 122.26(d)(2)(iv), including numeric design standards for stormwater runoff from new development and significant redevelopment consistent with the federal MEP standard (see State Water Board Order WQ 2000-11, the “LA SUSMP Order”). The Order also includes requirements for periodically evaluating and modifying or adding control measures, consistent with the concept that MEP is an evolving and flexible standard. 147 See, 55 Fed. Reg. 47990, 48052 (“EPA anticipates that storm water management programs will evolve and mature over time.”); 64 Fed. Reg. 68722, 68754; Dec. 8, 1999 (“EPA envisions application of the MEP standard as an iterative process.”); Interim Permitting Approach for Water Quality-Based Effluent Limitations in Stormwater Permits (Sept. 1, 1996) (“The interim permitting approach uses BMPs in firstround storm water permits, and expanded or better-tailored BMPs in subsequent permits, where necessary, to provide for the attainment of water quality standards.”); Revisions to the November 22, 2002 Memorandum “Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on LAs” (Nov. 26, 2014) (“In subsequent stormwater permit terms, if the BMPs used during prior years were shown to be inadequate to meet the requirements of the Clean Water Act (CWA), including attainment of applicable water quality standards, the permit would need to contain more specific conditions or limitations.”).

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B. Water Quality-Based Effluent Limitations (WQBELs)

1. Basis for WQBELs
In addition to requiring that MS4 permits include technology-based requirements consistent with the MEP standard, section 402(p)(3)(B)(iii) of the CWA requires that MS4 permits include “such other provisions as the Administrator or the State determines appropriate for the control of [] pollutants.”148 U.S. EPA interprets this provision to mandate “controls to reduce the discharge of pollutants to the maximum extent practicable, and where necessary water quality-based controls.”149 U.S. EPA has reiterated that MS4 “permit conditions must provide for attainment of applicable water quality standards (including designated uses), allocations of pollutant loads established by a TMDL, and timing requirements for implementation of a TMDL.”150 U.S. EPA Region IX has also affirmed the Water Boards’ position that MS4 discharges must meet water quality standards in a series of comment letters on MS4 permits issued by various California regional water boards.151 Likewise, the State Water Board has affirmed that MS4 permits must include requirements necessary to achieve compliance with the applicable technology-based standard of MEP and to achieve water quality standards.152 The permitting agency, be it the Los Angeles Water Board or U.S. EPA, must therefore include provisions in addition to those based on the MEP standard when it finds it is appropriate to do so and to exercise its discretion to determine what permit conditions are necessary to control pollutants in a specific geographic area.

Generally, discharge requirements designed to achieve water quality standards are referred to as water quality-based effluent limitations (WQBELs). A WQBEL is a restriction on the quantity or concentration of a pollutant that may be discharged from a point source into a receiving water that is necessary to achieve an applicable water quality standard in the receiving water.153 As discussed more fully below, WQBELs may be expressed narratively or numerically.

Federal NPDES regulations require the permitting agency to include WQBELs for point source discharges that cause, have the reasonable potential to cause, or contribute to an excursion above water quality standards.154 As the State Water 148 The early iterations (issued from 1990-1996) of the previous MS4 permits for Permittees in Los Angeles and Ventura Counties relied solely upon requirements consistent with the MEP standard to work toward achieving water quality standards. Note that the MEP standard is distinct from a water quality-based standard; each has a different basis. Therefore, while from a practical point of view, the goal of all MS4 permits is to control pollutants in discharges to ultimately achieve water quality standards, water quality based standards are directly derived from this desired outcome, while the MEP standard is anticipated to be a way of working toward the desired outcome, but is not directly derived from it. 149 Phase I Stormwater Regulations, Final Rule, 55 Fed. Reg. 47990, 47994 (Nov. 16, 1990) (emphasis added); see also Building Industry Ass’n of San Diego County v. State Water Resources Control Bd. (2004) 124 Cal.App.4th 866, 882-887.
150 See, e.g., Phase II Stormwater Regulations, Final Rule, 64 Fed. Reg. 68722, 68737. 151 See, e.g., letter from Alexis Strauss, Acting Director, Water Division, U.S. EPA Region IX, to Walt Pettit, Executive Director, State Water Board, re: SWRCB/OCC File A-1041 for Orange County, dated January 21, 1998.
152 See, e.g., State Water Board Orders WQ 99-05, WQ 2001-15, and WQ 2015-0075. 153 See 40 CFR § 122.2; NPDES Permit Writer’s Manual, Appendix A. A WQBEL is distinguished from a technology based effluent limitation (TBEL) in that the basis for the WQBEL is the applicable water quality standard for the receiving water, while the basis for the TBEL is generally the performance of the best available technology.
154 40 CFR § 122.44, subds. (d)(1)(i) and (d)(1)(iii).

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Board explained in 2001, “Urban runoff is causing and contributing to impacts on receiving waters throughout the state and impairing their beneficial uses....It is not enough simply to apply the technology-based standards of controlling discharges of pollutants to the MEP….”155 Nearly two decades later, this is still true.

In the Order, WQBELs are included where the Los Angeles Water Board or U.S.

EPA has determined that discharges from the MS4 cause, have the reasonable potential to cause, or contribute to an excursion above water quality standards.156 Reasonable potential can be demonstrated in several ways, one of which is through the TMDL development process. Where a point source is assigned a wasteload allocation (WLA)
157 in a TMDL, the analysis conducted in the
development of the TMDL provides the basis for the Los Angeles Water Board or U.S. EPA’s determination that the discharge has the reasonable potential to cause or contribute to an exceedance of water quality standards in the receiving water.

This approach is affirmed in U.S. EPA’s Permit Writer’s Manual, which states, “[w]here there is a pollutant with a WLA from a TMDL, a permit writer must develop WQBELs.”158
The Los Angeles Water Board and U.S. EPA have each established numerous TMDLs to address water quality impairments in the Los Angeles Region. Through the process of developing these TMDLs and assigning wasteload allocations to MS4 discharges in the Los Angeles Region, the Los Angeles Water Board and U.S.

EPA have established that MS4 discharges cause or contribute to exceedances of water quality standards. Given the number of Los Angeles Water Board and U.S.

EPA established TMDLs for impaired waters in the Los Angeles Region, there is ample evidence that MS4 discharges are a continuing and significant source of pollutants to the impaired receiving waters notwithstanding implementation of stormwater management programs driven by the MEP standard for the last three decades.

Where a TMDL has been established for a particular waterbody, U.S. EPA’s NPDES regulations further require that, “when developing water quality-based effluent limits…the permitting authority shall ensure that effluent limits … are consistent with the assumptions and requirements of any available wasteload allocation for the discharge…” (40 CFR § 122.44(d)(1)(vii)(B)). In its 2014 memorandum, Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs, U.S. EPA reaffirmed its 2002 interpretation that this regulation requires that “where a State or EPA has established a TMDL, NPDES permits must contain effluent limits and conditions consistent with the assumptions and requirements of the WLAs in the TMDL.”
159 This is inclusive of stormwater
155 State Water Board Order WQ 2001-15, pp. 7-8.
156 40 CFR §§ 122.44(d)(1)(i)-(iii); 122.44(d)(1)(vii)(B) 157 “Wasteload allocation” is defined as “[t]he portion of a receiving water’s loading capacity that is allocated to one if its existing or future point sources of pollution. WLAs constitute a type of water quality-based effluent limitation.” (40 CFR § 130.2(h)).
158 NPDES Permit Writers’ Manual, p. 6-30.
159 U.S. EPA, Memorandum, “Revisions to the November 22, 2002 Memorandum ‘Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs,’” (Nov. 26, 2014), p. 6 (emphasis added); see also U.S.

EPA, Memorandum, “Establishing Total Maximum Daily Load Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs,” (Nov. 22, 2002).

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permits – municipal, industrial and construction. U.S. EPA’s interpretation of its own regulation is entitled to deference. This requirement that WQBELs must be consistent with the assumptions and requirements of the WLAs means that the permit must include either an equivalent numeric effluent limit or “a measurable, objective BMP-based limit that is projected to achieve the WLA.”160 When a narrative WQBEL in the form of a BMP-based limit is relied upon, “the permit’s administrative record needs to provide adequate demonstration that … the BMPs … will be sufficient to implement applicable WLAs. … Improved knowledge of BMP effectiveness … should be reflected in the demonstration and supporting rationale that implementation of the BMPs will attain water quality standards and be consistent with WLAs.”161 Even if this regulation could be read to preclude mandatory incorporation of wasteload allocations into an MS4 permit, effluent limitations consistent with those wasteload allocations are nevertheless required under Clean Water Act section 402(p)(3)(B)(iii)’s direction that the MS4 permit shall require “such other controls” as the permitting authority determines “appropriate for the control of such pollutants.”162
Finally, California Water Code section 13377 requires that NPDES permits include effluent limitations necessary to implement water quality control plans, including TMDL requirements that have been incorporated into the water quality control plans.163
Therefore, the Los Angeles Water Board has included WQBELs in the Order for all pollutants for which a TMDL WLA is assigned to the MS4 discharges and the WQBELs are consistent with the assumptions and requirements of available TMDL WLAs applicable to the Permittees.

2. Expression of WQBELs
While federal law requires the Los Angeles Water Board to include TMDL-based WQBELs in the Order, it does not specify how those WQBELs are to be expressed in MS4 permits. Rather, federal law requires the permitting authority to make that determination as appropriate and necessary for the control of the discharge. In MS4 permits, WQBELs may be expressed either in narrative form (e.g., as requirements to implement specified BMPs) or in numeric form (i.e., as numeric effluent limitations). In the latter, the choice of how to achieve the numeric effluent limitations is left to the permittee.164 Both types of expression of the WQBELs are 160 Ibid.
161 Ibid.
162 33 U.S.C. § 1342(p)(3)(B)(iii). See, e.g., State Water Board Orders WQ 91-03, WQ 91-04, WQ 98-01, WQ 99-05, WQ 2001-15, and WQ 2015-0075.
163 Water Code section 13263, subd. (a) likewise requires waste discharge requirements to implement any relevant water quality control plans that have been adopted. See also State Water Res. Control Bd.

Cases (2006) 136 Cal. App. 4th 674, 730 (noting the obligation of the water boards to follow the program of implementation included in a water quality control plan). 164 CWA § 402(p)(3)(B)(iii); 40 CFR § 122.44(k); U.S. EPA. Memorandum, Revisions to the November 22, 2002 Memorandum “Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs,” (Nov. 26, 2014), p. 6. (noting that WQBELs “could take the form of a numeric limit, or of a measurable, objective BMP-based limit that is projected to achieve the WLA”); see also Defenders of Wildlife v. Browner (9th Cir. 1999) 191 F.3d 1159, 1166 (noting that the permitting authority has discretion regarding the nature and timing of requirements that it includes as MS4 permit conditions to attain water quality standards, and that these requirements may include numeric effluent limitations).

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allowed and neither one is more stringent than the other because an equivalent level of implementation of BMPs or other control measures is necessary to comply in either expression of the WQBELs. For example, to address MS4 discharges of trash, the permitting authority may require permittees to implement specific pollutant control measures, such as installing certified full capture systems on storm drains that prevent nearly all trash from reaching receiving waters (e.g., screens that trap particles of a certain size), partial capture devices on storm drains that prevent most trash from reaching receiving waters, or non-structural institutional controls (e.g., street sweeping, sidewalk trash cans, and anti-litter educational and outreach programs), or a combination of these three measures.

To comply with this narrative WQBEL expression, a permittee would need to demonstrate that it implemented the required control measures. Alternatively, the permitting authority may establish a numeric limit of zero trash discharged from the MS4. To comply with this numeric WQBEL expression, a permittee would still need to implement pollutant control measures on the ground, and these necessarily would include implementation of certified full capture systems, partial capture systems, or institutional controls, or any combination thereof. Functionally, compliance with either approach requires an equivalent level of implementation, although compliance with numeric WQBELs provides a greater level of flexibility.

The Los Angeles Water Board, as the permitting authority, must choose one of these options for each TMDL wasteload allocation and, in doing so, must ensure attainment of the wasteload allocations within the timeframes established in the TMDLs. Whether the WQBELs are expressed narratively or numerically are simply different ways to achieve the same desired water quality outcome.

Although federal regulations authorize the use of BMP-based WQBELs in stormwater permits to control the discharge of pollutants, those federal regulations and U.S. EPA guidance also state that BMP-based WQBELs are appropriate where it is “infeasible” to develop a numeric effluent limitation. 165 At the public
hearing for issuance of the 2012 Los Angeles County MS4 Permit, then Associate Director of the Water Division for U.S. EPA Region 9, confirmed that: “[T]he use of the term ‘feasible’ was to say is it feasible to translate the wasteload allocation into a numeric [effluent limitation] ….”166
U.S. EPA has issued two memoranda, on November 22, 2002 (2002 U.S. EPA Memorandum) and November 26, 2014 (2014 U.S. EPA Memorandum), providing guidance to permitting authorities on translating TMDL wasteload allocations into WQBELs in NPDES permits for stormwater discharges.167 The 2002 U.S. EPA Memorandum contemplated that “the NPDES permitting authority will review the information provided by the TMDL . . . and determine whether the effluent limit is appropriately expressed using a BMP approach (including an iterative BMP approach) or a numeric limit.”168 U.S. EPA further stated that it “expects that most WQBELs for NPDES-regulated municipal . . . storm water discharges will be in the 165 40 CFR § 122.44(k).
166 Transcript, Oct. 5, 2012, p. 225.
167 In addition to the two memoranda, U.S. EPA published guidance titled “Interim Permitting Approach for Water Quality-Based Effluent Limitations in Storm Water Permits” ((Sept. 1996) 61 Federal Register 57425), which recommended inclusion of BMPs in the first two to three rounds of permit issuance, and more specific BMPs or limitations in subsequent permits if the BMPs used during prior years were shown to be inadequate to meet the requirements of the Clean Water Act, including attainment of applicable water quality standards.
168 2002 U.S. EPA Memorandum, p. 5.

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form of BMPs, and that numeric limits will be used only in rare instances.”169 The 2014 U.S. EPA Memorandum updated aspects of the 2002 U.S. EPA Memorandum and constitutes U.S. EPA’s current guidance on this subject. After noting the increased information available to the permitting agencies after more than a decade of experience in setting wasteload allocations and WQBELs, the 2014 U.S. EPA Memorandum explained that:

Where the TMDL includes WLAs for stormwater sources that provide numeric pollutant loads, the WLA should, where feasible, be translated into effective, measurable WQBELs that will achieve this objective. This could take the form of a numeric limit, or of a measurable, objective BMPbased limit that is projected to achieve the WLA….The permitting authority’s decision as to how to express the WQBEL(s), either as numeric effluent limitations or as BMPs, with clear, specific, and measurable elements, should be based on an analysis of the specific facts and circumstances surrounding the permit, and/or the underlying WLA, including the nature of the stormwater discharge, available data, modeling results, and other relevant information.170
Where a BMP-based approach to permit limitations is selected, the 2014 U.S. EPA Memorandum noted that the permit’s administrative record needs to provide an adequate demonstration that implementation of the BMPs required in the permit will attain water quality standards and be consistent with the WLAs.171 As stated in Part II.F of this Fact Sheet, the three previous Orders included WQBELs consistent with the assumptions and requirements of available TMDL WLAs assigned to the Permittees’ MS4 discharges.

Except for wasteload allocations associated with certain TMDLs established by U.S. EPA (discussed below), the Los Angeles Water Board has expressed WQBELs in the Order as numeric effluent limitations as the default standard, but alternatively allows permittees the option to demonstrate compliance narratively.

Permittees may comply with the numeric WQBELs either by demonstrating compliance with the numeric WQBELs through monitoring or by implementing BMPs in approved Watershed Management Programs. Therefore, in essence, the Permit includes both numeric and narrative WQBELs. The Order contains both approaches to protect water quality and provide compliance flexibility for Permittees, while also following U.S. EPA guidance. Compliance with numeric WQBELs through monitoring and analysis of water samples collected from select representative MS4 discharge points is the default compliance standard.

Alternatively, Permittees may develop and implement an approved Watershed Management Program whereby they propose and implement certain approved BMPs that computer modeling demonstrates will meet the applicable numeric WQBELs by specified timeframes.

In determining how to express the WQBELs, the Los Angeles Water Board has analyzed the specific facts and circumstances surrounding the Order and the underlying TMDL WLAs, including the nature of MS4 discharges in the Los Angeles Region, available data, modeling results, and other relevant information. In doing so, the Los Angeles Water Board concludes that WQBELs expressed numerically 169 Id., p. 2.
170 2014 U.S. EPA Memorandum, p. 6.
171 Ibid.

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are appropriate and necessary in the Order to achieve the WLAs. MS4 discharges constitute a continuing and significant source of pollutants resulting in exceedances of water quality standards in the Los Angeles Region, as evidenced by the number of TMDLs established for impaired waters in the region and identification of MS4 discharges as a source of that impairment. To date, sole reliance on BMP-based requirements have been insufficient to resolve these exceedances. As such, the Los Angeles Water Board finds that WQBELs expressed numerically are necessary to address the historic and persistent exceedances of water quality standards in the Los Angeles Region.

Further, the Los Angeles Water Board concludes that numeric WQBELs are feasible. In the last 20 years, the Los Angeles Water Board and U.S. EPA have established 45 TMDLs for waterbodies in the Los Angeles Region in which WLAs are assigned to Phase I MS4 discharges. A significant part of developing each TMDL entailed analyzing pollutant sources and allocating loads to those sources using empirical relationships, quantitative modeling, and other relevant information.

As noted by the State Water Board when reviewing the numeric WQBELs in the 2012 Los Angeles County MS4 Permit, “In many ways, the Los Angeles MS4 Order was uniquely positioned to incorporate numeric WQBELs because of the extensive TMDL development in the region in the past decade and the documented role of MS4 discharges in contributing to the impairments addressed by those TMDLs.”172 Following the extensive work already conducted to develop the TMDLs, the Los Angeles Water Board continues to conclude that it is feasible to develop numeric WQBELs for MS4 discharges, and that the numeric WQBELs are consistent with the TMDL wasteload allocations. There is ample evidence that BMPs and other control measures can be designed proactively (through modeling) to divert, capture, and/or treat MS4 discharges such that it is possible for any such discharges to ultimately meet the numeric WQBELs according to established compliance schedules. The 7 WMPs and 12 EWMPs developed under the 2012 Los Angeles County MS4 Permit and, in particular, the Reasonable Assurance Analysis done in these WMPs/EWMPs demonstrate this. Further, given the variability in implementation of stormwater management programs across Permittees, numeric WQBELs create a measurable, objective, and accountable means of controlling MS4 discharges, while providing significant flexibility for Permittees to comply with the numeric WQBELs in any lawful manner, including by working with other Permittees as well as other government agencies and entities to implement cost-effective control measures.

While the Los Angeles Water Board finds that inclusion of numeric WQBELs in the Order is appropriate and necessary to achieve compliance with the TMDLs WLAs as required by federal law, at the same time, the Los Angeles Water Board also finds it appropriate to allow permittees to, alternatively and voluntarily, comply with the numeric WQBELs by implementing approved Watershed Management Programs comprised of a suite of BMP-based control measures. Watershed Management Programs must be accompanied by demonstrations, via computer modeling, that the BMPs will meet the numeric WQBELs. This alternative BMPbased option satisfies U.S. EPA’s guidance that MS4 permits include “effective, measurable WQBELs…that is projected to achieve the WLA.”173 172 Order WQ 2015-0075, p. 59.
173 2014 U.S. EPA Memorandum, p. 6.

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3. Interim and Final WQBELs
Final WQBELs are included in the Order based on the final WLAs assigned to MS4 discharges in all available TMDLs established for waterbodies in the Los Angeles Region.

MS4 permits can include compliance schedules for achieving final WQBELs derived from TMDL WLAs, so long as the compliance schedule is consistent with the program of implementation for the TMDL established by the Los Angeles Water Board and approved through the State’s basin plan amendment process (see Water Code §§ 13242, 13263, 13377). If a compliance schedule in an NPDES permit exceeds one year, it must include interim requirements and the dates for their achievement pursuant to 40 CFR section 122.47. As discussed later in this Fact Sheet, the Los Angeles Water Board is providing compliance schedules longer than one year for various pollutants consistent with TMDL programs of implementation. Where there is a program of implementation for a TMDL adopted by the Los Angeles Water Board and approved through the State’s basin plan amendment process, interim WQBELs are included in the Order based on interim WLAs established for MS4 discharges.

VI. RATIONALE FOR TOTAL MAXIMUM DAILY LOAD PROVISIONS
Pursuant to CWA section 402(p)(B)(3)(iii) and 40 CFR section 122.44(d)(1)(vii)(B), the Order includes requirements, including WQBELs, that are consistent with and implement WLAs that are assigned to discharges from the Permittees’ MS4s from 45 State-adopted and U.S.

EPA-established TMDLs. Permittees are required to comply with the TMDL Provisions in Part IV.B and Attachments K through S of the Order, including WQBELs and receiving water limitations which are consistent with the assumptions and requirements of the TMDL WLAs assigned to discharges from the Permittees’ MS4s. A comprehensive list of TMDLs by WMA and the Permittees subject to each TMDL is included in Attachment J of the Order.

A. Clean Water Act Section 303(d) List and Relationship to TMDLs Clean Water Act section 303(d)(1)(A) requires each State to conduct a biennial assessment of its waters and identify those waters that are not achieving water quality standards. These waters are identified as impaired on the State’s Clean Water Act section “303(d) List” of water quality limited segments. Periodically, U.S. EPA approves the State’s 303(d) List. Most recently, U.S. EPA approved the State’s 2014 and 2016 303(d) List of impaired water bodies on April 6, 2018, which includes certain receiving waters in the Los Angeles Region. Numerous water bodies within Los Angeles and Ventura counties do not meet water quality standards or fully support beneficial uses and therefore have been included on the State’s 303(d) List. For each 303(d) listed water body, the state or U.S. EPA is required to establish a Total Maximum Daily Load (TMDL), or implement alternative approaches as defined in U.S. EPA’s Long-Term Vision for Assessment, Restoration and Protection under the Clean Water Act Section 303(d) Program, for each pollutant impairing the water quality in that water body.174 B. TMDLs and Their Implementation Through NPDES Permits A TMDL is a tool for facilitating attainment of water quality standards and is based on the relationship between pollution sources and in-stream water quality conditions, 174 Alternative approaches to TMDLs include placement of a waterbody-pollutant combination in Category 4B of the 303(d) List or adoption of a Watershed Plan for nonpoint sources of pollution. Currently there are no alternative approaches adopted for the Los Angeles Region that apply to Phase I MS4 discharges.

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thereby providing the basis to establish water quality-based controls. A TMDL specifies the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards and allocates the acceptable pollutant load to point and nonpoint sources. The elements of a TMDL are described in 40 CFR sections 130.2 and 130.7.

A TMDL is defined as “the sum of the individual waste load allocations for point sources and load allocations for nonpoint sources and natural background.” (40 CFR § 130.2(i).) MS4 discharges are considered point source discharges.

Regulations further require that TMDLs must be set at “levels necessary to attain and maintain the applicable narrative and numeric water quality standards with seasonal variations and a margin of safety that takes into account any lack of knowledge concerning the relationship between effluent limitations and water quality.” (40 CFR section 130.7(c)(1).) 40 CFR section 130.7 also states that TMDLs shall take into account critical conditions for stream flow, loading and water quality parameters. These controls should provide the pollution reduction necessary for a water body to attain water quality standards. Essentially, TMDLs serve as a backstop provision of the Clean Water Act designed to ensure attainment of water quality standards when other provisions, such as technology-based effluent limitations, have failed to achieve water quality standards.

Upon establishment of TMDLs by the State or the U.S. EPA, the State is required to incorporate, or reference, the TMDLs in the State Water Quality Management Plan. (40 CFR sections 130.6(c)(1) and 130.7.) The Los Angeles Water Board’s Basin Plan, and applicable statewide water quality control plans, serves as the State Water Quality Management Plan governing the watersheds under the jurisdiction of the Los Angeles Water Board. When adopting TMDLs as part of its Basin Plan, the Los Angeles Water Board includes, as part of the TMDL, a program for implementation of the WLAs for point sources and load allocations (LAs) for nonpoint sources.

TMDLs are not self-executing, but instead rely upon further Board orders to impose pollutant restrictions on discharges to achieve the TMDL’s WLAs. Section 402(p)(3)(B)(iii) of the Clean Water Act requires the Los Angeles Water Board to impose permit conditions, including: “management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator of the State determines appropriate for the control of such pollutants.” (emphasis added.) Section 402(a)(1) of the Clean Water Act also requires states to issue permits with conditions necessary to carry out the provisions of the Clean Water Act. Federal regulations also require that NPDES permits include water quality-based effluent limitations consistent with the assumptions and requirements of any available waste load allocation for the discharge. (40 CFR section 122.44(d)(1)(vii)(B).) U.S. EPA has consistently stated that this regulation applies to all permitted stormwater discharges, including MS4 permits.175 Similarly, state law requires that the Los Angeles Water Board implement its Basin Plan when adopting waste discharge requirements (WDRs) and that NPDES permits apply “any more stringent effluent standards or limitations necessary to implement water quality control plans…” (Cal. Wat. Code, §§ 13263, 13377). In precedential State Water Board Order WQ 99-05, the State Water Board exercised its discretion under federal law by requiring MS4s to comply with water quality standards. In precedential Order WQ 2015-0075, the State Water Board reaffirmed that it would continue to require water quality standards compliance in MS4 permits. These 175 U.S. EPA Memorandum, “Revisions to the November 22, 2002 Memorandum ‘Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those TMDLs,’” p. 6 (Nov. 26, 2014).

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precedential orders are relevant as a TMDL, by its very nature, sets forth a plan for an impaired water body to achieve water quality standards.

An NPDES permit should include clear, specific, and measurable permit requirements, and where feasible, incorporate TMDL WLAs as numeric WQBELs.176 Where a nonnumeric permit limitation is selected, such as BMPs, the permit’s fact sheet and administrative record must support the expectation that the BMPs are sufficient to achieve the WLAs.177 (40 CFR § 124.8.) U.S. EPA has published guidance for establishing WLAs for stormwater discharges in TMDLs and their incorporation as numeric WQBELs, where feasible, in MS4 permits.178
C. TMDL Provisions
As required, WQBELs and receiving water limitations included in the Order and Attachments K through S are consistent with the assumptions and requirements of the available WLAs assigned to MS4 discharges in the Los Angeles Region, which have been established in forty-five (45) TMDLs. The Los Angeles Water Board established thirty-five (35) TMDLs and U.S. EPA established ten (10) TMDLs that assign WLAs to MS4 Permittees within the counties of Los Angeles and Ventura. These TMDLs identify MS4 discharges as a source of pollutants to these water bodies and, as required, establish WLAs for MS4 discharges to reduce the amount of pollutants discharged to receiving waters. While the TMDLs established by the Los Angeles Water Board include a program of implementation, including actions to be taken and a time schedule for such actions, TMDLs established by U.S. EPA do not. To date, the Los Angeles Water Board adopted three programs of implementation pursuant to Water Code sections 13240 and 13242 for four (4) U.S. EPA-established TMDLs. The TMDLs and programs of implementation included in the Regional MS4 Permit, along with establishment, approval, and effective dates, are listed in Table F-24 below.

The 2010 Ventura County MS4 Permit incorporated WQBELs and other permit requirements for thirteen (13) TMDLs. The Regional MS4 Permit continues to include WQBELs for all these TMDLs. The Regional MS4 Permit also continues to include other permit requirements for these TMDLs, except for the Calleguas Creek Nitrogen Compounds and Related Effects TMDL (Calleguas Creek Nitrogen TMDL). The Calleguas Creek Nitrogen TMDL identifies stormwater discharges as a minor source of nitrogen to Calleguas Creek; therefore, the TMDL did not assign WLAs to MS4 dischargers. The 2010 Ventura County MS4 Permit thus did not include WQBELs for this TMDL and the Regional MS4 Permit continues to not include WQBELs for this TMDL. However, monitoring requirements for the Calleguas Creek Nitrogen TMDL were included in the 2010 Ventura County MS4 Permit. The monitoring data from 2009 to 2017 had an exceedance rate of less than 1% of Nitrate as Nitrogen plus Nitrite as Nitrogen (1 exceedance out of 108 samples) at the monitored outfalls. Therefore, the Regional MS4 Permit does not include monitoring requirements for the Calleguas Creek Nitrogen TMDL.

The 2012 Los Angeles County MS4 Permit included WQBELs, receiving water limitations, and other permit requirements for thirty-three (33) TMDLs. The Regional MS4 Permit continues to include WQBELs, receiving water limitations, and other permit 176 Id., p. 3.
177 Id., p. 6.
178 U.S. EPA Memorandum, “Revisions to the November 22, 2002 Memorandum ‘Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those TMDLs’,” Nov. 26, 2014.

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requirements for all these TMDLs, except for the Bacterial Indicator TMDLs for Middle Santa Ana River Watershed (Middle Santa Ana River Bacteria TMDL). On August 26, 2005, the Santa Ana Regional Water Quality Control Board (Santa Ana Water Board) established the Middle Santa Ana River Bacteria TMDL, which assigned WLAs to the cities of Claremont and Pomona. The cities of Claremont and Pomona are located within the Los Angeles Water Board’s jurisdictional boundaries, but portions of their MS4 discharges drain to the Middle Santa Ana River Watershed. The 2012 Los Angeles County MS4 Permit contained WQBELs, receiving water limitations, and other permit requirements for the cities of Claremont and Pomona consistent with the Middle Santa Ana River Bacteria TMDL, but provided that the WQBELs, receiving water limitations, and other permit requirements would not be applicable during the effective dates of any NPDES permit that is issued by the Santa Ana Water Board. Pursuant to a valid and enforceable designation agreement between the Los Angeles Water Board and the Santa Ana Water Board under Water Code section 13228, dated May 31, 2013, the Santa Ana Water Board was designated as the regulator of discharges of bacteria from the cities of Claremont and Pomona through their MS4 to receiving waters within the Middle Santa Ana River Watershed. Therefore, the Regional MS4 Permit does not include WQBELs and other permit requirements implementing the Middle Santa Ana River Bacteria TMDL.

The 2014 City of Long Beach MS4 Permit included WQBELs and other permit requirements for nine (9) TMDLs, all of which continue to be included in the Regional MS4 Permit.

In addition, there are new TMDLs that the Los Angeles Water Board established, or U.S. EPA established, after the previous MS4 permits were issued. Table F-24 and Table F-25 below list all the TMDLs that are in the Order. Table F-25 indicates which TMDLs were in previous MS4 permits and which TMDLs are new to the Regional MS4 Permit.

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *522
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ATTACHMENT F – FACT SHEET F-157
Table F-24. Incorporated TMDLs and Programs of Implementation Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date

VENTURA RIVER WATERSHED
Ventura River Estuary
Trash TMDL
R4-2007-
008 6/7/2007 2007-0072 12/4/2007 2/11/2008 2/27/2008 3/6/2008 Ventura River Estuary
Trash TMDL (Revised)
R19-005 6/13/2019 2020-0002 1/21/2020 --- --- ---
TMDL for Algae, Eutrophic
Conditions, and Nutrients in
the Ventura River and its
Tributaries
R12-011 12/6/2012 2013-0005 2/19/2013 6/4/2013 6/28/2013 6/28/2013

MISCELLANEOUS VENTURA COASTAL WMA
Harbor Beaches of Ventura
County Bacteria TMDL R2007-017 11/1/2007 2008-0072 10/7/2008 12/9/2008 12/18/2008 12/18/2008

SANTA CLARA RIVER WATERSHED
Santa Clara River Nitrogen
Compounds TMDL 03-011 8/7/2003 2003-0073 11/19/2003 2/27/2004 3/18/2004 3/23/2004 Santa Clara River Estuary
and Reaches 3, 5, 6, and 7
Indicator Bacteria TMDL
R10-006 7/8/2010 2011-0048 10/4/2011 12/19/2011 1/13/2012 3/21/2012 TMDL for Chloride in the
Santa Clara River, Reach 3
(U.S. EPA established)
N/A N/A N/A N/A N/A 6/18/2003 6/18/2003
Upper Santa Clara River
Chloride TMDL R14-010 10/9/2014 2014-0069 12/16/2014 3/18/2015 4/28/2015 4/28/2015 Lake Elizabeth, Munz Lake,
and Lake Hughes Trash
TMDL (Lake Elizabeth only)
R4-2007-
009 6/7/2007 2007-0073 12/4/2007 2/8/2008 2/27/2008 3/6/2008 Lake Elizabeth, Munz Lake,
and Lake Hughes Trash
TMDL (Lake Elizabeth only)
(Revised)
R19-005 6/13/2019 2020-0002 1/21/2020 --- --- ---

EXHIBIT A
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ATTACHMENT F – FACT SHEET F-158
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date
Santa Clara River Lakes
Nutrients TMDL (Lake
Elizabeth only)
R16-006 9/8/2016 2017-0011 3/7/2017 6/22/2017 6/27/2017 6/27/2017

CALLEGUAS CREEK WATERSHED
TMDL for Organochlorine
(OC) Pesticides,
Polychlorinated Biphenyls
(PCBs), and Siltation in
Calleguas Creek, Its
Tributaries, and Mugu
Lagoon
R4-2005-
010 7/7/2005 2005-0068 9/22/2005 1/20/2006 3/14/2006 3/24/2006 TMDL for Toxicity,
Chlorpyrifos, and Diazinon
in the Calleguas Creek, its
Tributaries, and Mugu
Lagoon
R4-2005-
009 7/7/2005 2005-0067 9/22/2005 12/27/2005 3/14/2006 3/24/2006 TMDL for Metals and
Selenium in Calleguas
Creek, its Tributaries, and
Mugu Lagoon
R16-007 10/13/2016 2017-0007 2/22/2017 5/18/2017 6/9/2017 6/23/2017 Revolon Slough and
Beardsley Wash Trash
TMDL
R18-005 6/14/2018 2019-0018 5/21/2019 4/2/2020 5/6/2020 5/6/2020 TMDL for Boron, Chloride,
Sulfate, and TDS (Salts) in
the Calleguas Creek
Watershed
R4-2007-
016 10/4/2007 2008-0033 5/20/2008 11/6/2008 12/2/2008 12/2/2008 TMDLs for Pesticides,
PCBs, and Sediment
Toxicity in Oxnard Drain 3
(U.S. EPA established)
N/A N/A N/A N/A N/A 10/6/2011 10/6/2011

EXHIBIT A
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ATTACHMENT F – FACT SHEET F-159
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date

SANTA MONICA BAY WMA
Santa Monica Bay Beaches
Bacteria TMDL R12-007 6/7/2012 2013-0008 3/19/2013 11/7/2013 7/2/2014 7/2/2014 Santa Monica Bay Beaches
Bacteria TMDL (Revised) R21-001 3/11/2021 --- --- --- --- --- Santa Monica Bay
Nearshore and Offshore
Debris TMDL
R10-010 11/4/2010 2011-0064 12/6/2011 3/15/2012 3/20/2012 3/20/2012 Santa Monica Bay
Nearshore and Offshore
Debris TMDL (Revised)
R19-004 3/14/2019 2020-0001 1/21/2020 --- --- ---
Santa Monica Bay TMDL
for DDTs and PCBs (U.S.

EPA established)
N/A N/A N/A N/A N/A 3/26/2012 3/26/2012

MALIBU CREEK SUBWATERSHED
Malibu Creek and Lagoon
Bacteria TMDL R12-009 6/7/2012 2013-0008 3/19/2013 11/8/2013 7/2/2014 7/2/2014 Malibu Creek and Lagoon
Bacteria TMDL (Revised) R21-001 3/11/2021 --- --- --- --- --- Malibu Creek Watershed
Trash TMDL R18-006 6/14/2018 2019-0017 5/21/2019 4/2/2020 5/6/2020 5/6/2020 TMDLs for Nutrients -
Malibu Creek Watershed
(U.S. EPA established)
N/A N/A N/A N/A N/A 3/21/2003 3/21/2003
Malibu Creek & Lagoon
TMDL for Sedimentation
and Nutrients to Address
Benthic Community
Impairments (U.S. EPA
established)
N/A N/A N/A N/A N/A 7/2/2013 7/2/2013
Program of Implementation
for the U.S. EPAR16-009 12/8/2016 2017-0008 2/22/2017 5/16/2017 N/A 5/16/2017

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *525
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LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-160
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date
Established Malibu Creek
Nutrients TMDL and the
U.S. EPA-Established
Malibu Creek and Lagoon
Sedimentation and
Nutrients TMDL to Address
Benthic Community
Impairments
Program of Implementation
for the U.S. EPAEstablished Malibu Creek
Nutrients TMDL and the
U.S. EPA-Established
Malibu Creek and Lagoon
Sedimentation and
Nutrients TMDL to Address
Benthic Community
Impairments (Revised)
R21-001 3/11/2021 --- --- --- --- ---

BALLONA CREEK SUBWATERSHED
Ballona Creek Trash TMDL R15-006 6/11/2015 2015-0068 11/17/2015 5/4/2016 6/30/2016 6/30/2016 Ballona Creek Estuary
Toxic Pollutants TMDL R13-010 12/5/2013 2014-0030 6/17/2014 5/4/2015 10/26/2015 10/26/2015 Ballona Creek Estuary
Toxic Pollutants TMDL
(Revised)
R21-001 3/11/2021 --- --- --- --- ---
Ballona Creek, Ballona
Estuary and Sepulveda
Channel Bacteria TMDL
R12-008 6/7/2012 2013-0008 3/19/2013 11/8/2013 7/2/2014 7/2/2014 Ballona Creek, Ballona
Estuary and Sepulveda
Channel Bacteria TMDL
(Revised)
R21-001 3/11/2021 --- --- --- --- ---

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *526
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-161
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date
Ballona Creek Metals
TMDL R13-010 12/5/2013 2014-0030 6/17/2014 5/4/2015 10/26/2015 10/26/2015 Ballona Creek Metals
TMDL (Revised) R21-001 3/11/2021 --- --- --- --- ---
Ballona Creek Wetlands
TMDL for Sediments and
Invasive Exotic Vegetation
(U.S. EPA established)
N/A N/A N/A N/A N/A 3/26/2012 3/26/2012

MARINA DEL REY SUBWATERSHED
Marina del Rey Harbor
Mothers’ Beach and Back
Basins Bacteria TMDL
R12-007 6/7/2012 2013-0008 3/19/2013 11/7/2013 7/2/2014 7/2/2014 Marina del Rey Harbor
Mothers’ Beach and Back
Basins Bacteria TMDL
(Revised)
R21-001 3/11/2021 --- --- --- --- ---
Marina del Rey Harbor
Toxic Pollutants TMDL R14-004 2/6/2014 2014-0049 9/9/2014 5/4/2015 10/16/2015 10/16/2015 Marina del Rey Harbor
Toxic Pollutants TMDL
(Revised)
R21-001 3/11/2021 --- --- --- --- ---

DOMINGUEZ CHANNEL AND GREATER HARBORS WATERS WATERSHED
Los Angeles Harbor
Bacteria TMDL (Inner
Cabrillo Beach and Main
Ship Channel)
R12-007 6/7/2012 2013-0008 3/19/2013 11/7/2013 7/2/2014 7/2/2014 Dominguez Channel and
Greater Los Angeles and
Long Beach Harbor Waters
Toxic Pollutants TMDL
R11-008 5/5/2011 2012-0008 2/7/2012 3/21/2012 3/23/2012 3/23/2012

MACHADO LAKE SUBWATERSHED

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *527
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ATTACHMENT F – FACT SHEET F-162
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date
Machado Lake Trash TMDL R4-2007-
006 6/7/2007 2007-0075 12/4/2007 2/8/2008 2/27/2008 3/6/2008 Machado Lake Trash TMDL
(Revised)
R19-004 3/14/2019 2020-0001 1/21/2020 --- --- ---
Machado Lake Eutrophic,
Algae, Ammonia, and
Odors (Nutrient) TMDL
R08-006 5/1/2008 2008-0089 12/2/2008 2/19/2009 3/11/2009 3/11/2009 Machado Lake Pesticides
and PCBs TMDL R10-008 9/2/2010 2011-0065 12/6/2011 2/29/2012 3/20/2012 3/20/2012

LOS ANGELES RIVER WATERSHED
Los Angeles River
Watershed Trash TMDL R15-006 6/11/2015 2015-0068 11/17/2015 5/4/2016 6/30/2016 6/30/2016 Los Angeles River Nitrogen
Compounds and Related
Effects TMDL
R12-010 12/6/2012 2013-0016 6/4/2013 6/9/2014 8/7/2014 8/7/2014 Los Angeles River and
Tributaries Metals TMDL R15-004 4/9/2015 2015-0069 11/17/2015 7/11/2016 12/12/2016 12/12/2016 Los Angeles River
Watershed Bacteria TMDL R10-007 7/9/2010 2011-0056 11/1/2011 3/21/2012 3/23/2012 3/23/2012 Long Beach City Beaches
and Los Angeles River
Estuary Bacteria TMDL
(U.S. EPA established)
N/A N/A N/A N/A N/A 3/26/2012 3/26/2012
Legg Lake Trash TMDL R4-2007-
010 6/7/2007 2007-0074 12/4/2007 2/5/2008 2/27/2008 3/6/2008 Legg Lake Trash TMDL
(Revised)
R19-005 6/13/2019 2020-0002 1/21/2020 --- --- ---

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *528
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
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ATTACHMENT F – FACT SHEET F-163
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date
Los Angeles Area Lakes
TMDLs (U.S. EPA
established for Legg Lake,
Lake Calabasas, Echo Park
Lake, and Peck Road Park
Lake)
N/A N/A N/A N/A N/A 3/26/2012 3/26/2012

SAN GABRIEL RIVER WATERSHED
San Gabriel River and
Impaired Tributaries Metals
and Selenium TMDL (U.S.

EPA established)
N/A N/A N/A N/A N/A 3/26/2007 3/26/2007
Program of Implementation
for the TMDLs for Metals
and Selenium in the San
Gabriel River and Impaired
Tributaries
R13-004 6/6/2013 2014-0012 3/4/2014 10/13/2014 5/11/2017 10/13/2014 San Gabriel River, Estuary
and Tributaries Indicator
Bacteria TMDL
R15-005 6/10/2015 2015-0067 11/17/2015 4/14/2016 6/14/2016 6/14/2016 Los Angeles Area Lakes
TMDLs (U.S. EPA
established for
Puddingstone Reservoir)
N/A N/A N/A N/A N/A 3/26/2012 3/26/2012

LOS CERRITOS CHANNEL AND ALAMITOS BAY WATERSHED
Los Cerritos Channel
Metals TMDL (U.S. EPA
established)
N/A N/A N/A N/A N/A 3/17/2010 3/17/2010
Program of Implementation
for the TMDLs for Metals in
Los Cerritos Channel
R13-004 6/6/2013 2014-0012 3/4/2014 10/13/2014 5/11/2017 10/13/2014 Colorado Lagoon OC
Pesticides, PCBs, R09-005 10/1/2009 2010-0056 11/16/2010 5/6/2011 6/14/2011 7/28/2011

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *529
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-164
Total Maximum Daily
Load
Resolution
Number
Adoption
Date
State Water
Board
Resolution
Number
State Water
Board
Approval
Date
OAL
Approval
Date
U.S. EPA
Approval
Date
Effective
Date
Sediment Toxicity, PAHs
and Metals TMDL
Table F-25. Status of TMDLs in the Regional MS4 Permit and Previous MS4 Permits

TOTAL MAXIMUM DAILY LOAD
NEW TO
REGIONAL MS4
PERMIT
2012 LA
COUNTY
MS4
PERMIT
2014 CITY

OF LONG
BEACH
MS4
PERMIT
2010

VENTURA
COUNTY MS4
PERMIT

VENTURA RIVER WATERSHED
Ventura River Estuary Trash TMDL X
Total Maximum Daily Load for Algae, Eutrophic Conditions, and Nutrients in the Ventura River and its Tributaries X

MISCELLANEOUS VENTURA COASTAL WMA
Harbor Beaches of Ventura County Bacteria TMDL X

SANTA CLARA RIVER WATERSHED
Santa Clara River Nitrogen Compounds TMDL X X
Santa Clara River Estuary and Reaches 3, 5, 6, and 7
Indicator Bacteria TMDL X
TMDL for Chloride in the Santa Clara River, Reach 3 (U.S.

EPA established) X
Upper Santa Clara River Chloride TMDL X X
Lake Elizabeth, Munz Lake, and Lake Hughes Trash TMDL
(Lake Elizabeth only) X
Santa Clara River Lakes Nutrients TMDL (Lake Elizabeth
only) X

CALLEGUAS CREEK WATERSHED
TMDL for Organochlorine (OC) Pesticides, Polychlorinated Biphenyls (PCBs), and Siltation in Calleguas Creek, Its Tributaries, and Mugu Lagoon
X

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *530
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ATTACHMENT F – FACT SHEET F-165

TOTAL MAXIMUM DAILY LOAD
NEW TO
REGIONAL MS4
PERMIT
2012 LA
COUNTY
MS4
PERMIT
2014 CITY

OF LONG
BEACH
MS4
PERMIT
2010

VENTURA
COUNTY MS4
PERMIT
TMDL for Toxicity, Chlorpyrifos, and Diazinon in the
Calleguas Creek, its Tributaries, and Mugu Lagoon X
TMDL for Metals and Selenium in Calleguas Creek, its
Tributaries, and Mugu Lagoon X
Revolon Slough and Beardsley Wash Trash TMDL X
TMDL for Boron, Chloride, Sulfate, and TDS (Salts) in the Calleguas Creek Watershed X
TMDLs for Pesticides, PCBs, and Sediment Toxicity in
Oxnard Drain 3 (U.S. EPA established) X

SANTA MONICA BAY WMA
Santa Monica Bay Beaches Bacteria TMDL X
Santa Monica Bay Nearshore and Offshore Debris TMDL X
Santa Monica Bay TMDL for DDTs and PCBs (U.S. EPA
established) X

MALIBU CREEK SUBWATERSHED
Malibu Creek and Lagoon Bacteria TMDL X X
Malibu Creek Watershed Trash TMDL X
TMDLs for Nutrients - Malibu Creek Watershed (U.S. EPA
established) X X
Malibu Creek & Lagoon TMDL for Sedimentation and
Nutrients to Address Benthic Community Impairments (U.S.

EPA established)
X

BALLONA CREEK SUBWATERSHED
Ballona Creek Trash TMDL X
Ballona Creek Estuary Toxic Pollutants TMDL X
Ballona Creek, Ballona Estuary and Sepulveda Channel
Bacteria TMDL X
Ballona Creek Metals TMDL X
Ballona Creek Wetlands TMDL for Sediments and Invasive
Exotic Vegetation (U.S. EPA established) X

MARINA DEL REY SUBWATERSHED

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *531
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-166

TOTAL MAXIMUM DAILY LOAD
NEW TO
REGIONAL MS4
PERMIT
2012 LA
COUNTY
MS4
PERMIT
2014 CITY

OF LONG
BEACH
MS4
PERMIT
2010

VENTURA
COUNTY MS4
PERMIT
Marina del Rey Harbor Mothers’ Beach and Back Basins
Bacteria TMDL X
Marina del Rey Harbor Toxic Pollutants TMDL X

DOMINGUEZ CHANNEL AND GREATER HARBORS WATERS WATERSHED
Los Angeles Harbor Bacteria TMDL (Inner Cabrillo Beach
and Main Ship Channel) X
Dominguez Channel and Greater Los Angeles and Long
Beach Harbor Waters Toxic Pollutants TMDL X X

MACHADO LAKE SUBWATERSHED
Machado Lake Trash TMDL X
Machado Lake Eutrophic, Algae, Ammonia, and Odors
(Nutrient) TMDL X
Machado Lake Pesticides and PCBs TMDL X

LOS ANGELES RIVER WATERSHED
Los Angeles River Watershed Trash TMDL X X
Los Angeles River Nitrogen Compounds and Related
Effects TMDL X X
Los Angeles River and Tributaries Metals TMDL X X
Los Angeles River Watershed Bacteria TMDL X X
Long Beach City Beaches and Los Angeles River Estuary
Bacteria TMDL (U.S. EPA established) X X
Legg Lake Trash TMDL X
Los Angeles Area Lakes TMDLs (U.S. EPA established for
Legg Lake, Lake Calabasas, Echo Park Lake, and Peck
Road Park Lake)
X

SAN GABRIEL RIVER WATERSHED
San Gabriel River and Impaired Tributaries Metals and
Selenium TMDL (U.S. EPA established) X X
San Gabriel River, Estuary and Tributaries Indicator
Bacteria TMDL X

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *532
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-167

TOTAL MAXIMUM DAILY LOAD
NEW TO
REGIONAL MS4
PERMIT
2012 LA
COUNTY
MS4
PERMIT
2014 CITY

OF LONG
BEACH
MS4
PERMIT
2010

VENTURA
COUNTY MS4
PERMIT
Los Angeles Area Lakes TMDLs (U.S. EPA established for
Puddingstone Reservoir) X

LOS CERRITOS CHANNEL AND ALAMITOS BAY WATERSHED
Los Cerritos Channel Metals TMDL (U.S. EPA established) X X Colorado Lagoon OC Pesticides, PCBs, Sediment Toxicity, PAHs and Metals TMDL X X

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *533
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ATTACHMENT F – FACT SHEET F-168
D. Manner of TMDL Incorporation
The TMDLs incorporated into the Order express WLAs in different ways. In general, a WLA is a pollutant threshold that must be achieved in order to ensure that water quality standards are attained in the receiving water. The WLA may be expressed in terms of mass or concentration of a pollutant. However, in some cases, a WLA may be expressed as a receiving water condition such as an allowable number of exceedance days of the bacteria water quality objectives.

In the Order, TMDL WLAs have been translated into WQBELs and/or receiving water limitations that are consistent with the assumptions and requirements of the TMDL WLAs. The assumptions and requirements include, but are not limited to, numeric values and averaging periods. For those TMDLs that do not specify averaging periods for the WLAs, the averaging period for the WQBELs and/or receiving water limitations in the Order are based on the averaging period for the TMDL numeric targets. For each TMDL pollutant category, to the extent possible, the WLAs have been incorporated into the Order in a consistent manner. Some TMDLs specify alternative means of demonstrating compliance with WLAs; these alternative means of demonstrating compliance are included in the TMDL provisions in Part IV.B and Attachments K through S of the Order. The manner of incorporation for each TMDL pollutant category is discussed below in more detail.

A number of the TMDLs for various categories of pollutants such as bacteria, metals, and toxics establish WLAs that are assigned jointly to a group of Permittees whose stormwater and/or non-stormwater discharges are or may be commingled in the MS4 prior to discharge to the receiving water subject to the TMDL. TMDLs address commingled MS4 discharges by assigning a WLA to a group of MS4 Permittees based on co-location within the same subwatershed.

The applicability of TMDLs to Permittees as specified in Attachment J of the Order is consistent with the previous MS4 permits and the TMDLs. Where a TMDL assigns WLAs to categories of certain types of discharges or dischargers (e.g., MS4 permittees), but does not specifically name the “responsible Permittees”, current GIS data, drainage area boundaries, and other relevant information have been used to determine the applicability of a categorical WLA to individual Permittees.

1. Expression of Bacteria TMDLs as Permit Limitations
Ten bacteria TMDLs are incorporated into the Regional MS4 Permit as listed below:
▪ Harbor Beaches of Ventura County Bacteria TMDL (Attachment L) ▪ Santa Clara River Estuary and Reaches 3, 5, 6, and 7 Indicator Bacteria TMDL (Attachment M)
▪ Santa Monica Bay Beaches Bacteria TMDL (Attachment O) ▪ Malibu Creek and Lagoon Bacteria TMDL (Attachment O)
▪ Ballona Creek, Ballona Estuary and Sepulveda Channel Bacteria TMDL (Attachment O)
▪ Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL (Attachment O)
▪ Los Angeles Harbor Bacteria TMDL (Attachment P)
▪ Los Angeles River Watershed Bacteria TMDL (Attachment Q)

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *534
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-169
▪ Long Beach City Beaches and Los Angeles River Estuary Indicator Bacteria TMDL – U.S. EPA Established TMDL (Attachment Q)
▪ San Gabriel River, Estuary and Tributaries Indicator Bacteria TMDL (Attachment R)
In general, the bacteria TMDLs express the WLAs as an allowable number of exceedance days of the bacteria water quality objectives within the water body; therefore, the WLAs are translated into receiving water limitations. In addition to the receiving water limitations, WQBELs for MS4 outfalls are established to allow the opportunity for Permittees to individually demonstrate compliance at an outfall or jurisdictional boundary, thus isolating the Permittee’s pollutant contributions from those of other Permittees and from other pollutant sources to the receiving water.

The WQBELs are based on the bacteria water quality objectives in the Basin Plan at the time the TMDL was established.
179 For the bacteria TMDLs that apply to
marine and ocean waters,
180 the WQBELs are based on the multi-part
bacteriological water quality objectives for total coliform, fecal coliform and enterococcus. For the bacteria TMDLs for freshwater,181 the WQBELs are based on the bacteria water quality objectives for E. coli. No exceedances of the WQBELs are permitted unless expressly authorized by the TMDL (e.g., Santa Clara River Estuary and Reaches 3, 5, 6, and 7 Indicator Bacteria TMDL). The rationale for not allowing any exceedances of the WQBELs is that MS4 outfalls are monitored less frequently than the receiving waters, which are generally sampled at least weekly.

According to the equations used to express WLAs as allowable exceedance days in the bacteria TMDLs, as the frequency of monitoring decreases, the allowable number of exceedance days approaches zero, such that water quality objectives must be met for each monitoring event. Given the frequency at which outfalls are monitored, the allowable number of exceedance days for outfalls is zero and 179 In 2018, the State Water Board adopted statewide bacteria water quality objectives and implementation provisions to protect recreational users from the effects of pathogens in California water bodies (Bacteria Provisions). The Bacteria Provisions supersede numeric REC-1 water quality objectives for bacteria contained in a basin plan prior to the effective date of the Bacteria Provisions (February 4, 2019). The Los Angeles Water Board incorporated these Bacteria Provisions into the Basin Plan. The Bacteria Provisions did not change bacteria TMDLs established before February 4, 2019 and these TMDLs remain in effect. The Los Angeles Water Board may convene a public meeting to evaluate the effectiveness of these TMDLs in attaining the Bacteria Provisions at a later date. 180 These include: Harbor Beaches of Ventura County Bacteria TMDL (Attachment L); Santa Clara River Estuary and Reaches 3, 5, 6, and 7 Indicator Bacteria TMDL (discharges to the Santa Clara River Estuary and Santa Clara River Reaches 1 and 2) (Attachment M); Santa Monica Bay Beaches Bacteria TMDL (Attachment O); Malibu Creek and Lagoon Bacteria TMDL (discharges to the Lagoon) (Attachment O); Ballona Creek, Ballona Estuary and Sepulveda Channel Bacteria TMDL (discharges to the Estuary) (Attachment O); Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL (Attachment O); Los Angeles Harbor Bacteria TMDL (Attachment P); Long Beach City Beaches and Los Angeles River Estuary Indicator Bacteria TMDL – U.S. EPA Established TMDL (Attachment Q); and San Gabriel River, Estuary, and Tributaries Indicator Bacteria TMDL (discharges to the San Gabriel River Estuary) (Attachment R).
181 These include: Santa Clara River Estuary and Reaches 3, 5, 6, and 7 Indicator Bacteria TMDL (discharges to Santa Clara River Reaches 3 and above) (Attachment M); Malibu Creek and Lagoon Bacteria TMDL (Malibu Creek discharges) (Attachment O); Ballona Creek, Ballona Estuary and Sepulveda Channel Bacteria TMDL (Ballona Creek and Sepulveda Channel discharges) (Attachment O); Los Angeles River Watershed Bacteria TMDL (Attachment Q); and the San Gabriel River, Estuary and Tributaries Indicator Bacteria TMDL (discharges to the San Gabriel River and tributaries) (Attachment R).

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therefore no exceedances of the WQBELs are permitted unless otherwise specified.

The following TMDLs require additional discussion either because the manner of incorporation has changed from previous MS4 permits or information in the TMDL regarding the naming of responsible Permittees requires clarification.

Santa Monica Bay Beaches Bacteria TMDL, Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL, Los Angeles Harbor Bacteria TMDL, and Long Beach City Beaches and Los Angeles River Estuary Indicator Bacteria TMDL. A change that was made in the Order from the way these bacteria TMDLs were previously incorporated into the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit is the removal of open beach compliance locations. Since the Order regulates MS4 discharges, only sampling sites that are or could be impacted by an MS4 discharge are included as receiving water compliance locations. MS4 compliance locations are defined as sites that are within 400 yards of storm drain outfalls.
182 Open beach sites are regulated
under a different mechanism, such as the Nonpoint Source Program.

For the Santa Monica Bay Beaches Bacteria TMDL (SMB Bacteria TMDL) specifically, the removal of open beach compliance locations affects the calculation of the interim wet-weather single sample indicator bacteria receiving water limitations for each jurisdictional group. The SMB Bacteria TMDL’s interim wetweather milestones were based on a cumulative percentage reduction from the total wet-weather exceedance-day reductions required for each jurisdictional group. These reduction milestones were translated into the number of exceedance days to be reduced plus the number of annual allowable wet-weather exceedance days for each jurisdictional group. By July 15, 2018, the SMB Bacteria TMDL required each jurisdictional group to achieve a 50% cumulative percent reduction from the total wet-weather exceedance-day reductions required for each jurisdictional group as defined in Table 7-4.2b of the Basin Plan . Table 7-4.2b defines each jurisdictional group and the monitoring sites assigned to that group, which includes both open beach and MS4 compliance locations. The Order incorporates the SMB Bacteria TMDL interim wet-weather milestones as interim wet-weather receiving water limitations to be achieved by the effective date of the Order. For each jurisdictional group, the interim wet-weather receiving water limitations have been recalculated to remove open beach compliance locations. In addition, for MS4 compliance locations that are sampled weekly instead of daily, the interim wet-weather receiving water limitations have been scaled according to equation 8.2 in the Santa Monica Bay Beaches Wet-Weather Bacteria TMDL staff report dated November 7, 2002.

Santa Clara River Estuary and Reaches 3, 5, 6, and 7 Indicator Bacteria TMDL (SCR Bacteria TMDL). Unlike other bacteria TMDLs, the SCR Bacteria TMDL only provided values for allowable exceedance days when daily sampling is conducted and provided equations to calculate values for more or less frequent sampling.

Interim annual allowable exceedance days of the single sample water quality objective are calculated for daily, weekly, and less than weekly (3 wet and 2 dry weather) sampling frequencies according to the equation included in Table 7-36.3 of the Basin Plan. Final annual allowable exceedance days are calculated for daily 182
“An Epidemiological Study of Possible Adverse Health Effects of Swimming in Santa Monica Bay.” Santa Monica Bay Restoration Project.

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and weekly sampling frequencies according to the equation included in Table 7-

36.2 of the Basin Plan.

The SCR Bacteria TMDL identifies wet weather as the critical condition. However, the TMDL did not define the wet-weather period. Therefore, the wet-weather period for the SCR Bacteria TMDL is determined based on the same approach as the Santa Monica Bay Beaches Bacteria TMDL (a day with 0.1 inch of rain or greater and the three days following the rain event).
183
The Order identifies the City of Oxnard as one of the responsible Permittees for the SCR Bacteria TMDL even though the TMDL contains conflicting direction about the inclusion of the City of Oxnard. While the TMDL assigns WLAs to different general categories of pollutants184, the implementation section of the TMDL does not specifically name the City of Oxnard as one of the entities responsible for MS4 WLAs.185 However, the TMDL Staff Report does name the City of Oxnard as one of the entities responsible for MS4 WLAs186 and shows the City as discharging to Reach 1 and Reach 2, which drain to the Estuary, in Figure 2-1 of the TMDL Staff Report187. Therefore, including the City of Oxnard as a responsible Permittee for the SCR Bacteria TMDL is consistent with the assumptions and requirements of the TMDL.

The Order includes indicator bacteria WQBELs for MS4 dischargers that discharge to Reaches 3 or above based on allowable exceedance days for Reaches 3, 5, 6, and 7. Ventura County Permittees have not been assigned indicator bacteria WQBELs for discharges to Reaches 4B, 5, 6, and 7 because there are no MS4 discharges from Ventura County MS4 Permittees to these reaches. For Reaches 6 and 7, the drainage area for MS4 discharges is completely within Los Angeles County. Reach 5 partially falls within Ventura County, but Ventura County Permittees do not have any MS4 discharges to the portion of Reach 5 that falls within Ventura County188. This is consistent with the TMDL Staff Report, which shows a map of the Santa Clara River Reach 5 subwatershed as draining mainly Los Angeles County.189 Therefore, the Order assigns indicator bacteria WQBELs for discharges to Reach 5 exclusively to Los Angeles County Permittees draining to Reach 5. For Reach 4B, although it is completely within Ventura County190, there are no MS4 discharges from Ventura County Permittees to Santa Clara River Reach 4B. The Order may be reopened to name Ventura County Permittees as responsible Permittees for Santa Clara River Reach 4B and 5 if there is future development of MS4 infrastructure and discharges to these reaches. 183 Los Angeles Water Board. Total Maximum Daily Loads for Indicator Bacteria in Santa Clara River Estuary and Reaches 3, 5, 6, and 7 [Staff Report]. July 8, 2010. p. 49. 184 Los Angeles Water Board. Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties.

Chapter 7 p. 7-433.
185 Los Angeles Water Board. Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties.

Chapter 7 p. 7-435
186 Los Angeles Water Board. Total Maximum Daily Loads for Indicator Bacteria in Santa Clara River Estuary and Reaches 3, 5, 6, and 7 [Staff Report]. July 8, 2010. pp. 52-53. 187 Los Angeles Water Board. Total Maximum Daily Loads for Indicator Bacteria in Santa Clara River Estuary and Reaches 3, 5, 6, and 7 [Staff Report]. July 8, 2010. p. 23. 188 Ventura County GIS data and MS4 drainage area maps (July 15, 2016) 189 Los Angeles Water Board. Total Maximum Daily Loads for Indicator Bacteria in Santa Clara River Estuary and Reaches 3, 5, 6, and 7 [Staff Report]. July 8, 2010. p. 15. 190 Ventura County GIS data and MS4 drainage area maps (July 15, 2016)

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2. Expression of Metals TMDLs as Permit Limitations
Six metals TMDLs are incorporated into the Regional MS4 Permit as listed below:
▪ Metals and Selenium in the Calleguas Creek, its Tributaries and Mugu Lagoon TMDL (Attachment N)
▪ Ballona Creek Metals TMDL (Attachment O)
▪ Los Angeles River and Tributaries Metals TMDL (Attachment Q) ▪ TMDLs for Metals and Selenium - San Gabriel River and Impaired Tributaries – U.S. EPA Established TMDL (Attachment R)
▪ Los Angeles Area Lakes TMDLs: Puddingstone Reservoir Mercury TMDL – U.S. EPA Established TMDL (Attachment R)
▪ Los Cerritos Channel TMDLs for Metals – U.S. EPA Established TMDL (Attachment S)
The following TMDLs require additional discussion because the manner of incorporation has changed from previous MS4 permits.

Los Angeles River and Tributaries Metals TMDL, Ballona Creek Metals TMDL, San Gabriel River and Impaired Tributaries Metals and Selenium TMDL, and Los Cerritos Channel Metals TMDL. These TMDLs assign mass-based WLAs to the Permittees during dry-weather and wet-weather conditions expressed as mass per day. For ease of implementation, these WLAs are incorporated into the Order as mass-based WQBELs as well as alternative concentration-based WQBELs.

Demonstrating compliance with concentration-based values rather than massbased values is more practical given the nature of monitoring requirements in the Order.

The TMDLs’ dry-weather numeric targets are used for the alternative concentration-based dry-weather WQBELs. This approach is consistent with the assumptions and requirements of these TMDLs. The Los Angeles River and Tributaries Metals TMDL and Ballona Creek Metals TMDL both state that concentration-based permit limits equal to dry-weather reach-specific numeric targets may apply during dry weather.191 The San Gabriel River and Los Cerritos Channel TMDLs do not contain this explicit language, but as they follow the same calculation approach as the Los Angeles River and Ballona Creek TMDLs, the same approach for incorporation into permits may apply.

The wet-weather mass-based WLAs are expressed as equations. In the Order, the terms of these equations have been rearranged to express WQBELs as an “effective concentration” of a metal that when multiplied by the volume of flow in the river for the assessed day (i.e. the daily volume in liters) gives the calculated effluent limitation as a load.

𝐸𝑓𝑓𝑙𝑢𝑒𝑛𝑡 𝐿𝑖𝑚𝑖𝑡𝑎𝑡𝑖𝑜𝑛 = (𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒) As an example, the grouped wet-weather effluent limitation for cadmium in the Los Angeles River is a load expressed as kg/day:
191 Los Angeles Water Board. Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties.

Chapter 7 p. 7-132 (Ballona Creek Metals TMDL) and p. 7-156 (Los Angeles and Tributaries Metals TMDL).

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𝐸𝑓𝑓𝑙𝑢𝑒𝑛𝑡 𝐿𝑖𝑚𝑖𝑡𝑎𝑡𝑖𝑜𝑛 = 𝑊𝐸𝑅 𝑥 (2.8𝑥10−9
) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒) − 1.8
Setting the two equations equal and rearranging the variables to solve for the “effective concentration,” the equation becomes:
(𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
= 𝑊𝐸𝑅 𝑥 (2.8𝑥10−9
) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒) − 1.8
𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 =
𝑊𝐸𝑅 𝑥 (2.8𝑥10−9
) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒) − 1.8
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑊𝐸𝑅 𝑥 (2.8𝑥10−9
) −

1.8 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
This equation results in an effective concentration for cadmium expressed as kg/L; to convert to μg/L, apply the conversion factor 1 kg = 1 x 109 μg:

𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = [𝑊𝐸𝑅 𝑥 (2.8𝑥10−9
) −

1.8 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
] (
1 𝑥 109 𝜇𝑔
1 𝑘𝑔 )
𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 2.8 −

1.8 𝑥 109
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
The concentration WQBELs for the Los Angeles River and Tributaries Metals TMDL based on this methodology are the following:

𝐶𝑎𝑑𝑚𝑖𝑢𝑚 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 2.8 −

1.8 𝑥 109
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
𝐶𝑜𝑝𝑝𝑒𝑟 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 15 −

9.5 𝑥 109
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
𝐿𝑒𝑎𝑑 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 85 −

3.2 𝑥 1010
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
𝑍𝑖𝑛𝑐 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 140 −

8.3 𝑥 1010
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
The Los Angeles River Metals TMDL defines wet weather as any day when the maximum daily flow instream is equal to or greater than 500 cfs at the Wardlow station. A flow of 500 cfs results in a daily volume of 1.22 x 109 L. Using this daily volume, a WER default value of 1 except for copper, which has a site-specific WER of 3.97, in these equations result in the following effective concentrations:

𝐶𝑎𝑑𝑚𝑖𝑢𝑚: 1 𝑥 2.8 −

1.8 𝑥 109

1.22 𝑥 109 = 1.32
𝜇𝑔
𝐿
𝐶𝑜𝑝𝑝𝑒𝑟: 3.97 𝑥 15 −

9.5 𝑥 109

1.22 𝑥 109 = 51.76
𝜇𝑔
𝐿
𝐿𝑒𝑎𝑑: 1 𝑥 85 −

3.2 𝑥 1010

1.22 𝑥 109 = 58.77
𝜇𝑔
𝐿

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𝑍𝑖𝑛𝑐: 1 𝑥 140 −

8.3 𝑥 1010

1.22 𝑥 109 = 71.97
𝜇𝑔
𝐿
The equations for the wet-weather mass-based WQBELs for the Ballona Creek Metals TMDL, San Gabriel River Metals TMDL, and Los Cerritos Channel Metals TMDL are simpler than for the Los Angeles River Metals TMDL because they do not account for the allocations for wastewater treatment plants. Thus, when the equations for the Ballona Creek Metals TMDL, San Gabriel River Metals TMDL, and Los Cerritos Channel Metals TMDL are rearranged, the effective concentration is a value. As an example, the grouped wet-weather effluent limitation for copper in Ballona Creek is a load expressed as grams per day:

𝐸𝑓𝑓𝑙𝑢𝑒𝑛𝑡 𝐿𝑖𝑚𝑖𝑡𝑎𝑡𝑖𝑜𝑛 = 𝑊𝐸𝑅 𝑥 (1.297 𝑥 10−5
) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
As in the previous example, the effluent limitation is expressed as an “effective concentration”:

𝐸𝑓𝑓𝑙𝑢𝑒𝑛𝑡 𝐿𝑖𝑚𝑖𝑡𝑎𝑡𝑖𝑜𝑛 = (𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒) Setting the two equations equal and rearranging the variables to solve for the “effective concentration” the equation becomes:
(𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
= 𝑊𝐸𝑅 𝑥 (1.297 𝑥 10−5
) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 =
𝑊𝐸𝑅 𝑥 (1.297 𝑥 10−5
) 𝑥 (𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
(𝑑𝑎𝑖𝑙𝑦 𝑣𝑜𝑙𝑢𝑚𝑒)
𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑊𝐸𝑅 𝑥 1.297 𝑥 10−5
This equation results in an effective concentration for copper expressed as g/L; to convert to μg/L, apply the conversion factor 1 g = 1 x 106 μg:

𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = (𝑊𝐸𝑅 𝑥 1.297 𝑥 10−5) (
1 𝑥 106 𝜇𝑔
1 𝑔
)
𝐸𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 12.97
The concentration WQBELs for the Ballona Creek Metals TMDL based on this methodology are the following:

𝐶𝑜𝑝𝑝𝑒𝑟 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 12.97
𝐿𝑒𝑎𝑑 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 72.65
𝑍𝑖𝑛𝑐 (
𝜇𝑔
𝐿
) = 𝑊𝐸𝑅 𝑥 99.17
This methodology for determining effective concentrations to be used as the alternative wet-weather concentration-based WQBELs is consistent with the assumptions and requirements of these TMDLs because the equations are the same as the WLA equations assigned by the TMDLs; the terms have merely been rearranged for ease of compliance determination.

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3. Expression of Nutrient TMDLs as Permit Limitations
Twelve nutrient TMDLs are incorporated into the Regional MS4 Permit as listed below:
▪ TMDL for Algae, Eutrophic Conditions, and Nutrients in the Ventura River and its Tributaries (Attachment K)
▪ Santa Clara River Nitrogen Compounds TMDL (Attachment M) ▪ Santa Clara River Lakes Nutrients TMDL (Lake Elizabeth) (Attachment M) ▪ TMDLs for Nutrients - Malibu Creek Watershed – U.S. EPA Established TMDLs (Attachment O)
▪ Malibu Creek and Lagoon TMDL for Sedimentation and Nutrients to Address Benthic Community Impairments – U.S. EPA Established TMDLs (Attachment O)
▪ Machado Lake Eutrophic, Algae, Ammonia, and Odors (Nutrient) TMDL (Attachment P)
▪ Los Angeles River Nitrogen Compounds and Related Effects TMDL (Attachment Q)
▪ LA Area Lakes TMDLs: Echo Park Lake Nutrient TMDL – U.S. EPA Established TMDL (Attachment Q)
▪ LA Area Lakes TMDLs: Peck Road Park Lake Nutrient TMDL – U.S. EPA Established TMDL (Attachment Q)
▪ LA Area Lakes TMDL: Legg Lake System Nutrient TMDL – U.S. EPA Established TMDL (Attachment Q)
▪ LA Area Lakes TMDLs: Lake Calabasas Nutrient TMDL – U.S. EPA Established TMDL (Attachment Q)
▪ LA Area Lakes TMDL: Puddingstone Reservoir Nutrient TMDL – U.S. EPA Established (Attachment R)
The following TMDLs require additional discussion either because the manner of incorporation has changed from previous MS4 permits or there is inconsistent information in the TMDL about the naming of responsible Permittees.

Santa Clara River Lakes Nutrients TMDL (Lake Elizabeth only). The Santa Clara River Lakes Nutrients TMDL assigns grouped WLAs to all MS4 discharges for Lake Elizabeth, Munz Lake, and Lake Hughes. Only WLAs for Lake Elizabeth were incorporated in Attachment M of the Order because there are no Permittee discharges subject to the Order into Lake Hughes or Lake Munz. 192 The WLAs for
MS4 discharges to Munz Lake and Lake Hughes were assigned to additional responsible entities in the future under Phase II of the U.S. EPA Stormwater Permitting Program; or the residual designation authority of the state under Clean Water Action section 402(p)(2)(E), and other applicable regulatory programs. 193
Los Angeles River Nitrogen Compounds and Related Effects TMDL. In the Los Angeles River Nitrogen Compounds and Related Effects TMDL (LAR Nitrogen 192 Total Maximum Daily Load for Nutrients in Elizabeth Lake, Munz Lake, and Lake Hughes in the Santa Clara River Watershed [Staff Report]. September 8, 2016. Table 4 pp. 16-17. 193 Los Angeles Water Board. Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties.

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TMDL) the total ammonia as nitrogen WLAs are dependent on the temperature and pH of receiving waters as well as the presence of early life stages (ELS) of fish. The WQBELs incorporated into the Regional MS4 Permit for total ammonia as nitrogen are based on the calculation procedure for translation of objectives into effluent limits in Chapter 3 of the Basin Plan, page 3-16 to 3-25. Following this procedure is consistent with the LAR Nitrogen TMDL, which states, “It would be consistent with the findings and assumptions of this TMDL to calculate total ammonia WLAs based on temperature and pH data from the most recent three years of monitoring data when incorporating WLAs into permits. In applying this approach, 90th percentile pH data shall be used to establish one-hour average WLAs and the 50th percentile of pH and temperature data shall be used to establish 30-day average WLAs. The procedure for translation of objectives into effluent limits specified in Chapter 3 of this Basin Plan, as amended by Resolution R02- 011 and R04-022, shall be used to translate WLAs into effluent limitations.” The three years of receiving water monitoring data used to calculate the ammonia WQBELs were from the Donald C. Tillman Water Reclamation Plant (WRP), the Los Angeles-Glendale WRP, and the Whittier Narrows WRP.

The Donald C. Tillman WRP is located at the Sepulveda Basin and discharges to Reach 5. There are receiving water monitoring stations in Reach 5 (Sepulveda Basin) and Reach 4 (below Sepulveda Basin). Monitoring data from receiving water monitoring stations RSW-LATT628 (Reach 5) and RSW-LATT630 (Reach 4) were used to calculate the ammonia site specific 30-day average limitations. The Los Angeles-Glendale WRP discharges to Los Angeles River Reach 3. Monitoring data from receiving water monitoring station RSW-LAGT650 (Reach 3) were used to calculate the ammonia site specific 30-day average limitations. Whittier Narrows WRP is located adjacent to Rio Hondo Reach 3 (above Whittier Narrows Dam).

Monitoring data from receiving water monitoring station RSW-006 (Rio Hondo Reach 3) were used to calculate the ammonia site specific 30-day average limitations. For the three WRPs, the receiving water monitoring data from January 1, 2018 to December 31, 2020, were used to calculate the 50th percentile for pH and temperature values, which were used to calculate the ammonia WQBELs.

4. Expression of Salts TMDLs as Permit Limitations
Three salts TMDLs are incorporated into the Regional MS4 Permit as listed below:
▪ Santa Clara River Reach 3 Chloride TMDL – U.S. EPA Established TMDL (Attachment M)
▪ Upper Santa Clara River Chloride TMDL (Attachment M)
▪ Calleguas Creek Watershed Salts TMDL (Attachment N)
The following TMDLs require additional discussion either because the manner of incorporation has changed from previous MS4 permits or there is inconsistent information in the TMDL about the naming of responsible Permittees.

Santa Clara River Reach 3 Chloride TMDL. The SCR Reach 3 Chloride TMDL recommends incorporating WLAs as an instantaneous maximum. However, the WLAs were incorporated into Attachment M of the Order as a daily maximum.

Based on the monitoring frequency required in the MRP of the Order, the daily maximum is effectively the same as an instantaneous maximum WQBEL.

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Upper Santa Clara River Chloride TMDL. The Upper Santa Clara River Chloride TMDL (USCR Chloride TMDL) includes a 3-month rolling average WLA for chloride. However, the 2012 Los Angeles County MS4 Permit includes WLAs as an instantaneous maximum. Based on the monitoring frequency required in the MRP of the Order, the daily maximum is effectively the same as an instantaneous maximum. Therefore, consistent with the 2012 Los Angeles County MS4 Permit, the WLA for chloride is incorporated in Attachment M of the Order as a daily maximum WQBEL.

Although the USCR Chloride TMDL did not specifically list individual responsible Permittees, it assigned WLAs to “Other NPDES discharges.” Consistent with the SCR Bacteria TMDL, Ventura County Permittees have not been assigned chloride WQBELs for discharges to the upper reaches of the Santa Clara River (Reaches 4Band 5) because there are no MS4 discharges from Ventura County MS4 Permittees to these reaches.
194
Boron, Chloride, Sulfate, and TDS (Salts) in the Calleguas Creek Watershed TMDL (Calleguas Creek Salts TMDL). Among the other Permittees specifically named in the Calleguas Creek Salts TMDL, the Los Angeles Water Board has determined that the Cities of Oxnard and Simi Valley are responsible Permittees for this TMDL because their MS4s discharge to the subwatersheds to which the TMDL assigns WLAs (Pleasant Valley (Revolon) and Simi)195. This determination was made based on current GIS information on MS4s and their drainage areas.

5. Expression of Toxic Pollutants and Sediment TMDLs as Permit Limitations There are twenty-one (21) toxic pollutants and sediment TMDLs that are incorporated into the Regional MS4 Permit as listed below:
▪ Calleguas Creek OC Pesticides and PCBs TMDL (Attachment N) ▪ Calleguas Creek Toxicity TMDL (Attachment N)
▪ TMDLs for Pesticides, PCBs, and Sediment Toxicity in Oxnard Drain 3 – U.S.

EPA Established (Attachment N)
▪ Santa Monica Bay TMDLs for DDTs and PCBs – U.S. EPA established (Attachment O)
▪ Ballona Creek Estuary Toxic Pollutants TMDL (Attachment O) ▪ Ballona Creek Wetlands TMDLs for Sediment and Invasive Exotic Vegetation – U.S. EPA established (Attachment O)
▪ Marina del Rey Harbor Toxic Pollutants TMDL (Attachment O) ▪ Dominguez Channel and Greater Los Angeles and Long Beach Harbor Waters Toxic Pollutants TMDL (Attachment P)
▪ Machado Lake Pesticides and PCBs TMDL (Attachment P)
▪ LA Area Lakes TMDLs: Echo Park Lake Chlordane, Dieldrin and PCBs TMDL – U.S. EPA Established (Attachment Q)
▪ LA Area Lakes TMDLs: Peck Road Park Lake Chlordane, Dieldrin, DDTs and PCBs TMDL – U.S. EPA Established (Attachment Q)
▪ LA Area Lakes TMDLs: Puddingstone Reservoir Chlordane, Dieldrin, DDTs and PCBs TMDLs – U.S. EPA Established (Attachment R)
▪ Colorado Lagoon OC Pesticides, PCBs, Sediment Toxicity, PAHs, and Metals TMDL (Attachment S)
194 Ventura County GIS data and MS4 drainage area maps (July 15, 2016). 195 Los Angeles Water Board. Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties.

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The following TMDLs require additional discussion either because the manner of incorporation has changed from previous MS4 permits or there is inconsistent information in the TMDL about the manner of incorporation.

Organochlorine (OC) Pesticides, Polychlorinated Biphenyls (PCBs), and Siltation in Calleguas Creek, its Tributaries, and Mugu Lagoon TMDL (Calleguas Creek OC Pesticides and PCBs TMDL). The Calleguas Creek OC Pesticides and PCBs TMDL includes a siltation WLA, which is allocated to all NPDES permitted MS4s, including Caltrans. The WLA is expressed as a reduction from the baseline sediment yield to Mugu Lagoon. The TMDL states on page 7 that “the [waste] load allocation will apply after the baseline is established, as described in the Implementation Plan.” The TMDL Implementation Plan requires Ventura County Permittees to propose a baseline load per Special Study #1. Ventura County Permittees have completed Special Study #1. However, the study did not determine the baseline sedimentation yield but rather claimed that Mugu Lagoon is unimpaired for sedimentation based on habitat conversion and benthic community degradation. Mugu Lagoon has not been removed from the 303(d) list for sedimentation. Nonetheless, until a baseline sedimentation yield is calculated, it is not possible to incorporate the sedimentation WLA into the Order because of the way the WLA is expressed in the TMDL. Therefore, the siltation WLA for Mugu Lagoon is not incorporated into Attachment N of the Order. The Los Angeles Water Board will reopen the Order to incorporate a siltation WLA depending upon the decision regarding the impairment status of Mugu Lagoon.

Calleguas Creek Toxicity TMDL. The Toxicity, Chlorpyrifos, and Diazinon in the Calleguas Creek, its Tributaries, and Mugu Lagoon TMDL (Calleguas Creek Toxicity TMDL) includes 1-hour (acute) and 4-day (chronic) WLAs for both chlorpyrifos and diazinon. Based on the monitoring frequency required in the MRP of the Order, the daily maximum is effectively the same as the 1-hour and 4-day frequency. Hence, WLAs are incorporated as a daily maximum. Consistent with other Los Angeles Water Board-adopted toxics TMDLs, acute WLAs were interpreted to apply to wet weather and chronic WLAs were interpreted to apply to dry weather.

E. WQBELs for Trash

1. Previous Permit Requirements
The Los Angeles Water Board amended the 2001 Los Angeles County MS4 Permit (Order No. 01-182) on December 10, 2009 to incorporate provisions implementing the Los Angeles River Trash TMDL. At that time, the Los Angeles Water Board incorporated the WLAs from the Los Angeles River Trash TMDL into the 2001 Los Angeles County MS4 Permit as numeric WQBELs.
196 The 2001 Los Angeles
County MS4 Permit stated: “Each Permittee identified in Appendix 7-1 shall comply with the interim and final effluent limitations set forth in Appendix 7-1 hereto.”197 Appendix 7-1 expressed the numeric effluent limitations for trash as progressively decreasing allowable amounts of trash discharged from each applicable permittee’s jurisdictional area within the watershed. Each applicable permittee was 196 See generally 2001 Permit, Part 7, pp. 79-84, Appendix 7-1, and Appendix 7-2. See also, 2001 Permit, Findings Related to the Incorporation of the Los Angeles River Trash TMDL, pp. 15-20; see also 2012 Permit, Fact Sheet, pp. F-13, F-23..
197 2001 Permit, Part 7, p. 79 and Appendix 7-1.

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required to make annual reductions of its discharges of trash over a 7-year period (2010-2016), until the final effluent limitation of zero trash discharged from the MS4 was achieved. “Permittees shall achieve their final effluent limitation of zero trash discharge for the 2015-2016 storm year and every year thereafter.”198 Consistent with the TMDL, the Los Angeles Water Board provided Permittees the option to be deemed in compliance with the numeric effluent limitations through the installation of certain BMPs (i.e., certified full capture devices). 199
In the 2012 Los Angeles County MS4 Permit, the Los Angeles Water Board carried over the effluent limitations and compliance deadlines, as well as the compliance approaches, established in the 2001 Los Angeles County MS4 Permit.200 Part A of Attachment O of the 2012 Los Angeles County MS4 Permit included the interim and final numeric WQBELs and compliance deadlines implementing the Los Angeles River Trash TMDL. Applicable permittees were required to “comply with the final water quality-based effluent limitation of zero trash discharged to the Los Angeles River no later than September 30, 2016 and every year thereafter.”201 The 2012 Los Angeles County MS4 Permit also included provisions implementing 8 other trash TMDLs, including interim and final numeric WQBELs and compliance deadlines and provisions outlining the method of compliance for all trash TMDLs.

The 2014 City of Long Beach MS4 Permit included similar requirements for the Los Angeles River Trash TMDL. As discussed in Part II.F of this Fact Sheet, the 2012 Los Angeles County MS4 Permit was reopened in 2016 to incorporate revisions to the Los Angeles River Trash TMDL and Ballona Creek and Wetlands Trash TMDL.

At the same time, the 2014 City of Long Beach MS4 Permit was also reopened to incorporate the same revisions to the Los Angeles River Trash TMDL. The 2010 Ventura County MS4 Permit included provisions for the Revolon Slough and Beardsley Wash Trash TMDL and the Ventura River Estuary Trash TMDL. These provisions in the Ventura County MS4 Permit included WLAs expressed as WQBELs of “zero trash”, compliance monitoring, and actions and special studies.

2. Manner of Trash TMDLs Incorporation
There are eleven (11) trash TMDLs that are incorporated into the Regional MS4 Permit, listed below, consistent with the assumptions and requirements of the TMDL WLAs.
• Ventura River Estuary Trash TMDL (Attachment K)
• Lake Elizabeth Trash TMDL (Attachment M)
• Revolon Slough and Beardsley Wash Trash TMDL (Attachment N) • Santa Monica Bay Nearshore and Offshore Debris TMDL (Attachment O) • Malibu Creek Watershed Trash TMDL (Attachment O)
198 Id., Part 7, Appendix 7-1, footnote 3.
199 Id., Part 7, pp. 79-84 and Appendix 7-2.
200 2012 Permit, Part VI.E.5, pp. 151-157 and Attachment O, Part A, pp. O-1 to O-3.. See also id., Fact Sheet, p. F-37 (“This Order carries over the final receiving water limitations and WQBELs that were included to implement the Marina del Rey Harbor Back Basins and Mothers’ Beach Bacteria TMDL and the Los Angeles River Trash TMDL, respectively, in the 2007 and 2009 amendments to Order No. 01- 182.”).
201 Id., Part A.2, p. O-1..

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• Ballona Creek Trash TMDL (Attachment O)
• Machado Lake Trash TMDL (Attachment P)
• Los Angeles River Watershed Trash TMDL (Attachment Q) • Legg Lake Trash TMDL (Attachment Q)
• LA Area Lakes TMDLs: Echo Park Lake Trash TMDL – U.S. EPA Established (Attachment Q)
• LA Area Lakes TMDLs: Peck Road Park Lake Trash TMDL – U.S. EPA Established (Attachment Q)
The WLAs for trash are expressed as progressively decreasing allowable amounts of trash discharged from a Permittee’s jurisdictional area within the drainage area to the impaired water body. The Trash TMDLs require each Permittee to make annual reductions of its discharges of trash over a set period, until the numeric target of zero trash discharged from the MS4 is achieved. The Trash TMDLs specify a specific formula for calculating and allocating annual reductions in trash discharges from each jurisdictional area within a watershed. The formula results in specified annual amounts of trash that may be discharged from each jurisdiction into the receiving waters. Translation of the WLAs or compliance points described in the TMDLs into jurisdiction-specific load reductions from the baseline levels, as specified in the TMDL, logically results in the articulation of an annual limitation on the amount of a pollutant that may be discharged. The specification of allowable annual trash discharge amounts meets the definition of an “effluent limitation”, as that term is defined in subdivision (c) of section 13385.1 of the California Water Code. Alternatively, if Permittees choose to comply with the WLAs for trash by progressively installing full capture systems to address 100% of the drainage area to the impaired waterbody within their jurisdiction, the specification of the percentage of the drainage area (or percentage of catch basins) that must be addressed meets the definition of an “effluent limitation.” Specifically, the trash discharge limitations or, alternatively, percentage of area addressed by full capture systems constitute a “numeric restriction … on the quantity [or] discharge rate … of a pollutant or pollutants that may be discharged from an authorized location.”

3. Compliance Schedules for Trash TMDLs
Trash TMDL compliance schedules are incorporated into the Regional MS4 Permit consistent with the TMDLs. Note that the Santa Monica Bay Debris TMDL included a mechanism where Permittees would receive a three-year extension of the final TMDL implementation deadline if they adopted certain local ordinances. The cities of Manhattan Beach, Hermosa Beach, and Malibu adopted local ordinances to ban plastic bags, smoking in public places, and single use expanded polystyrene food packaging. Therefore, the final TMDL implementation deadline for these Permittees is extended from March 20, 2020 to March 20, 2023.

4. Trash TMDLs Compliance Methods
Part IV.B.3 of the Order sets forth the trash WQBELs, Permittees’ compliance options with respect to trash WBQELs, and additional trash TMDL provisions. The compliance options included in the Order are consistent with the compliance options included in the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits, with the exception of the following:

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a. Under the 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits, a Permittee could request a less frequent assessment of its daily generation rate (DGR) subject to Executive Officer approval. Part IV.B.3.b.ii.(a)(1)(iii) of the Order, however, allows Permittees to reduce the frequency of DGR recalculation to every five years upon achieving full compliance with final WQBELs without the requirement for Executive Officer approval. This change was made due to the time and tracking costs associated with tracking and responding to such requests and does not affect requirements for annual reporting and, thus, the ability to assess compliance with the final WQBELs on an ongoing basis.
b. Two trash TMDL compliance approaches included in previous MS4 permits, “Partial Capture Devices and Institutional Controls” and “Combined Compliance Approaches,” have been combined into the “Mass Balance Compliance Approach” detailed in Part IV.B.3.b.ii of the Order. This approach allows Permittees to comply with their interim and final effluent limitations using a combination of full capture systems, partial capture devices, and institutional controls. Furthermore, performance of full capture systems and partial capture devices (i.e., trash removal efficiency) may be accounted for in calculating the “Total Storm Year Trash Discharge,” using the forms provided in Attachment I of the Order. The change to combine the “Partial Capture Devices and Institutional Controls” and “Combined Compliance Approaches” from the previous permits does not constitute a change in trash TMDL compliance options.
c. Additionally, the Order takes into account additional full capture system compliance options for the Malibu Creek Watershed Trash TMDL and the Revolon Slough and Beardsley Wash Trash TMDL. These additional full capture system compliance options are consistent with recent updates to these TMDLs, which are now in effect (See Table F-24). These compliance options allow Permittees to demonstrate compliance with the WQBELs by installing certified full capture systems on conveyances that collect drainage from priority land use areas as defined in the Trash Amendments.

F. U.S. EPA Established TMDLs
U.S. EPA has established ten TMDLs that include waste load allocations for MS4 discharges in Los Angeles and Ventura counties. These TMDLs are listed below with their effective dates:
• March 21, 2003 – TMDLs for Nutrients - Malibu Creek Watershed (Attachment O) • June 18, 2003 – TMDL for Chloride in the Santa Clara River, Reach 3 (Attachment M)
• March 26, 2007 – TMDLs for Metals and Selenium - San Gabriel River and Impaired Tributaries (Attachment R)
• March 17, 2010 – Los Cerritos Channel TMDLs for Metals (Attachment S) • October 6, 2011 – TMDLs for Pesticides, PCBs, and Sediment Toxicity in Oxnard Drain 3 (Attachment N)
• March 26, 2012 – Santa Monica Bay TMDLs for DDTs and PCBs (Attachment O)

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• March 26, 2012 – Ballona Creek Wetlands TMDLs for Sediment and Invasive Exotic Vegetation (Attachment O)
• March 26, 2012 – Long Beach City Beaches and Los Angeles River Estuary TMDLs for Indicator Bacteria (Attachment Q)
• March 26, 2012 – Los Angeles Area Lakes TMDLs for Nitrogen, Phosphorus, Mercury, Trash, Organochlorine Pesticides and PCBs (Attachments O, Q, and R) • July 2, 2013 – Malibu Creek and Lagoon TMDL for Sedimentation and Nutrients to Address Benthic Community Impairments (Attachment O)
As discussed above, in contrast to State-established TMDLs, U.S. EPA-established TMDLs do not contain a program of implementation. The Clean Water Act does not allow U.S. EPA to either adopt programs of implementation or establish implementation schedules for its TMDLs. Such decisions are generally left with the states. The Los Angeles Water Board may, and has in some cases, subsequently adopted a separate program of implementation as a Basin Plan Amendment for U.S. EPA-established TMDLs, including schedules of implementation, which can be included as compliance schedules in permits where applicable. Alternatively, considering the specific approach taken in the Regional MS4 Permit and specific facts pertaining to the U.S. EPAestablished TMDLs, the Los Angeles Water Board can determine that no compliance schedule should be provided or may approve a schedule in a Watershed Management Program.

In the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit, Permittees subject to WLAs in U.S. EPA-established TMDLs were required to propose and implement best management practices (BMPs) that would be effective in achieving compliance with U.S. EPA-established numeric WLAs and a schedule to implement the proposed BMPs in their WMPs. The Los Angeles Water Board’s approach in these two prior permits was based the fact that the TMDLs were being newly incorporated and, because they did not have State adopted programs of implementation, the numeric WLAs would take effect immediately. Further, through the WMP Provisions in these two permits, the Los Angeles Water Board created an alternative compliance pathway that provided a rigorous process for identifying BMPs and a schedule for implementing the BMPs that would ensure that the WLAs would be achieved. Therefore, the Los Angeles Water Board determined that it was appropriate to express the TMDL WLAs as narrative WQBELs and allow Permittees to propose BMPs to meet the numeric WLAs and a schedule that was as short as possible in a Watershed Management Program during the terms of these two permits. If Permittees did not propose such BMPs in their WMPs, and receive approval of their WMP, they were required to immediately comply with numeric WQBELs equivalent to the numeric WLAs.
202

In developing the Order, the Los Angeles Water Board revisited, and is clarifying, its approach to U.S. EPA-established TMDL WLAs in the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit, which these permits anticipated the Los Angeles Water Board would do. In revisiting its approach, the Los Angeles Water Board considered (a) whether it had adopted a program of implementation for the TMDL pursuant to Water Code sections 13240 and 13242; (b) whether the WLAs for the U.S. EPA-established TMDL were equivalent to existing pollutant loads (thus 202 Note that per 40 CFR § 130.2(h) “WLAs constitute a type of water quality-based effluent limitation [WQBEL].”

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requiring no reductions); (c) whether Permittees were currently achieving the WLAs; and (d) whether load reductions are still required to meet the WLAs.

In some cases, the Los Angeles Water Board is allowing Permittees the option to continue implementing proposed BMPs per a specified schedule in a Watershed Management Program. In other cases, the Los Angeles Water Board is incorporating compliance schedules where it has adopted a program of implementation for the U.S.

EPA TMDL. And, finally, in some cases, the Los Angeles Water Board has concluded that additional time to comply with the TMDL-based WQBELs is not needed. The manner of incorporation and compliance schedules for each of the U.S. EPA TMDLs is set forth and explained below.

1. U.S. EPA TMDLs with State Programs of Implementation The Los Angeles Water Board adopted the following three separate programs of implementation to address four U.S. EPA-established TMDLs:
• Implementation Plan for the (a) TMDLs for Nutrients - Malibu Creek Watershed and the (b) Malibu Creek and Lagoon TMDL for Sedimentation and Nutrients to Address Benthic Impairments (effective date: May 16, 2017) • Implementation Plan for the TMDLs for Metals and Selenium - San Gabriel River and Impaired Tributaries (effective date: October 13, 2014) • Implementation Plan for the Los Cerritos Channel TMDLs for Metals (effective date: October 13, 2014)
For these U.S. EPA-established TMDLs, the WLAs are incorporated into the Order as numeric WQBELs and/or receiving water limitations with corresponding compliance schedules consistent with the TMDLs and programs of implementation adopted by the Los Angeles Water Board. Permittees have the option to address these U.S. EPA-established TMDLs in a Watershed Management Program in the same manner as Los Angeles Water Board-adopted TMDLs.

Through establishment of these state programs of implementation the Los Angeles Water Board has undergone a comprehensive evaluation of implementation strategies, cost considerations including the estimated cost of implementing the measures to achieve the WLAs, and the time required to fully implement control measures to achieve the final WLAs.

2. U.S. EPA TMDLs That Do Not Have State Programs of Implementation The remaining six U.S. EPA established TMDLs do not have State programs of implementation. The Los Angeles Water Board’s decision as to how to incorporate WQBELs and/or receiving water limitations for these six U.S. EPA established TMDLs is based on an evaluation of (1) whether the WLAs in the U.S. EPAestablished TMDLs were based on existing MS4 loads and (2) whether Permittees were currently achieving WLAs.
a. U.S. EPA TMDLs Where WLAs Were Based on Existing MS4 Loads at Time of TMDL Adoption
After a fact-specific re-evaluation of how each U.S. EPA-established TMDL should be incorporated, the Los Angeles Water Board has determined that numeric WQBELs and/or receiving water limitations must be achieved by the effective date of the Order for the U.S. EPA-established TMDLs where the WLAs were established equal to existing MS4 pollutant loads. The following

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TMDLs established by U.S. EPA have WLAs that are equivalent to existing MS4 pollutant loads at the time of TMDL adoption:
• Santa Monica Bay TMDLs for DDTs and PCBs203
• Ballona Creek Wetlands TMDLs for Sediment and Invasive Exotic Vegetation204
• Echo Park Lake Nutrients TMDL and Peck Road Park Lake Nutrients TMDL205
For these TMDLs, the U.S. EPA TMDL specifies that the WLAs are set equal to the existing pollutant loads at the time of TMDL adoption. Therefore, no reductions in pollutant loads should be required. Permittees must continue to maintain and not increase pollutant loads in MS4 discharges as compared to the WLAs. Accordingly, these WLAs are incorporated as numeric WQBELs and/or receiving water limitations that must be complied with as of the effective date of the Order. No compliance schedules or alternative to propose BMPs and schedules of implementation in Watershed Management Programs are provided.
b. U.S. EPA TMDLs Where Permittees Are Achieving WLAs
For U.S. EPA-established TMDLs where Permittees are currently achieving WLAs, the Los Angeles Water Board has also incorporated these WLAs as numeric WQBELs and/or receiving water limitations that must be complied with as of the effective date of the Order. The rationale for this manner of incorporation is further explained below.

The previous MS4 Permits required Permittees to propose and implement BMPs to achieve compliance with the WLAs. Therefore, the Los Angeles Water Board evaluated the Permittees’ TMDL implementation strategies, monitoring data, and the time required to fully implement control measures to achieve the final WLAs in the WMPs and Annual Reports. Based on this information, the Los Angeles Water Board determined that Permittees will be able to comply immediately with the numeric WQBELs and/or receiving water limitations as of the effective date of the Order.

Based on this information, for the following TMDLs, the WLAs are incorporated as numeric WQBELs and/or receiving water limitations that must be complied with as of the effective date of the Order. No compliance schedules or alternative to propose BMPs and schedules of implementation in Watershed Management Programs are provided.

Santa Clara River Reach 3 Chloride TMDL. On June 18, 2003, U.S. EPA established the TMDL for Chloride in the Santa Clara River Reach 3 (SCR Reach 3 Chloride TMDL). Based on outfall monitoring data (site IDs MO-SPA and MO-FIL) from October 2010 through May 2017, there were three 203 U.S. EPA. Santa Monica Bay Total Maximum Daily Loads for DDTs and PCBs. March 26, 2012. pp. 49-

51. 204 U.S. EPA. Ballona Creek Wetlands Total Maximum Daily Loads for Sediment and Invasive Exotic Vegetation. March 26, 2012. pp. 73-74.
205 U.S. EPA. Los Angeles Area Lakes Total Maximum Daily Loads for Nitrogen, Phosphorus, Mercury, Trash, Organochlorine Pesticides and PCBs. March 26, 2012. pp. 6-17 and 4-18.

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exceedances out of 51 samples of the 80 mg/L WQBEL206. Furthermore, recent monitoring data from January 2018 to January 2019 for these outfall sites indicate no exceedances out of 19 samples. For these reasons, the WLA in the SCR Reach 3 Chloride TMDL is incorporated in Attachment Q of the Order as a numeric WQBEL and no compliance schedule or option to propose BMPs and an implementation schedule in a Watershed Management Program is included. Thus, this numeric WQBEL must be complied with as of the effective date of the Order.

Echo Park Lake Trash TMDL and the Peck Road Park Lake Trash TMDL.

The Echo Park Lake Trash TMDL and Peck Road Park Lake Trash TMDL are part of the Los Angeles Area Lakes TMDLs for Nitrogen, Phosphorus, Mercury, Trash, Organochlorine Pesticides and PCBs. The Upper Los Angeles River EWMP 2017-18 Annual Report (p. 29) for the Echo Park Lake Trash TMDL states, “The target of zero trash established in the Echo Park Lake Trash TMDL was met at Echo Park Lake.” The Upper Los Angeles River EWMP is the only Watershed Management Program that addresses Echo Park Lake. Having achieved the TMDL WLA, Permittees are expected to maintain compliance.

The Rio Hondo/San Gabriel River EWMP proposed September 30, 2016 as the final compliance date to meet the Peck Road Park Lake Trash TMDL (Table 2-10, p. 59 of the EWMP), which has passed. The City of Irwindale reports in the 2017-18 Annual Report (p. 23) that they have achieved full compliance with the Peck Road Park Lake Trash TMDL. The City of El Monte in their WMP (pp. 1-57 to 1-58) states that the City does not discharge to Peck Road Park Lake. In summary, for the Peck Road Park Lake Trash TMDL Permittees have either proposed a compliance schedule for which the final deadline has passed or have reported full compliance in their latest annual reports; therefore, Permittees are expected to be in compliance and maintain compliance with the TMDL WLAs.

For these reasons, the WLAs in the Echo Park Lake Trash TMDL and Peck Road Park Lake Trash TMDL were incorporated in Attachment Q of the Order as numeric WQBELs that must be complied with as of the effective date of the Order. No compliance schedules or alternative to propose BMPs and additional schedules of implementation in Watershed Management Programs are provided.
c. Remaining U.S. EPA TMDLs
Some U.S. EPA-established TMDLs without state programs of implementation have WLAs that were not based on existing pollutant loads, therefore, they required pollutant load reductions; and Permittees may still not be meeting the WLAs.

The following U.S. EPA established TMDLs are included in the Order as narrative WQBELs whereby Permittees have the option of proposing BMPs that have a reasonable assurance of achieving the TMDL WLAs along with a schedule to implement the BMPs that is as short as possible in a Watershed Management Program. The State Water Board upheld this approach in WQ206 California Environmental Data Exchange Network (CEDEN). Accessed August 7, 2020. https://ceden.waterboards.ca.gov/AdvancedQueryTool.

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2015-0075.207 The Los Angeles Water Board may, at its discretion, revisit this decision within the term of the Order or in a future permit, as more information is developed to support the inclusion of numeric WQBELs for these U.S. EPAestablished TMDLs:
• TMDLs for Pesticides, PCBs, and Sediment Toxicity in Oxnard Drain 3 • Long Beach City Beaches and Los Angeles River Estuary Indicator Bacteria TMDL
• Los Angeles Area Lakes TMDLs for Nitrogen, Phosphorus, Mercury, Trash, OC Pesticides and PCBs
o Legg Lake System Nutrient TMDL
o Lake Calabasas Nutrient TMDL
o Echo Park Lake Chlordane, Dieldrin and PCBs TMDL
o Peck Road Park Lake Chlordane, Dieldrin, DDTs and PCBs TMDL o Puddingstone Reservoir Nutrient, Mercury, Chlordane, Dieldrin, DDTs and PCBs TMDLs
For these U.S. EPA established TMDLs, the Order allows Permittees subject to these TMDLs to propose and implement BMPs that will be effective in achieving the TMDL WLAs in a Watershed Management Program, subject to Los Angeles Water Board approval. 208 Where these TMDLs were previously included in the 2012 Los Angeles County MS4 Permit and 2014 City of Long Beach MS4 Permit, some Permittees have already done so. In the case of Ventura County Permittees, the 2010 Ventura County MS4 Permit did not include the alternative to develop and implement a Watershed Management Program and, further, the one TMDL applicable to the Ventura County Permittees that is in this category is a TMDL that is newly incorporated into the Order.

For Permittees developing a Watershed Management Program, or revising an existing approved Watershed Management Program, Permittees must propose a schedule for implementing the BMPs that is as short as possible.

The Los Angeles Water Board finds that, at this time, it is reasonable to include permit requirements for some of the U.S. EPA established TMDLs that allow Permittees to develop Watershed Management Programs that include BMPs, interim requirements and schedules for actions to achieve the TMDL WLAs.

More detail on the required elements of a Watershed Management Program is included in Part X of this Fact Sheet. These Watershed Management Programs will facilitate a comprehensive planning process, including coordination among Permittees where necessary, on a watershed basis to identify the most effective watershed control measures and implementation strategies to achieve the TMDL WLAs much like a state program of implementation for a TMDL facilitates.

Based on the nature and timing of the proposed watershed control measures, the Los Angeles Water Board will consider appropriate actions on its part, which may include: (1) no action and continued reliance on permit 207 State Water Board Order WQ 2015-0075, pp. 59-61.
208 The requirements for Permittees who do not choose to participate in a WMP are set forth infra.

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requirements that require implementation of the approved watershed control measures throughout the permit term per an approved Watershed Management Program; (2) adopting a program of implementation and corresponding schedule through the Basin Plan Amendment process and then incorporating a compliance schedule into this Order consistent with the Stateadopted program of implementation; or (3) issuing a separate enforcement order (e.g., Time Schedule Order or Cease and Desist Order) to provide the necessary time to fully implement the watershed control measures to achieve the WQBELs.

Further detail on specific TMDLs is provided below, including limitations to schedules proposed in a Watershed Management Program.

Long Beach City Beaches and Los Angeles River Estuary Indicator Bacteria TMDL. The Long Beach City Beaches and Los Angeles River Estuary Indicator Bacteria TMDL (LB City Beaches and LA River Estuary Bacteria TMDL) addresses the Long Beach City Beaches that drain an area of 505 acres within the City of Long Beach. The TMDL, on page 6, refers to this drainage area as the “LBC beaches direct drainage” where there are five “sewersheds,” or storm drain basins that collect, convey, and discharge stormwater and dry weather flow from these basins to the impaired beaches.

Flows from other adjacent areas are directed away from the Long Beach City Beaches.

To determine whether additional time for BMP implementation is appropriate for the Long Beach City Beaches during dry weather conditions, the Los Angeles Water Board considered the manner this TMDL was previously incorporated into the City of Long Beach MS4 Permit. Per Part VIII.G.1.c.iv.(1) of the 2014 City of Long Beach MS4 Permit, it states that “For the City of Long Beach City Beaches Bacteria TMDL established by U.S. EPA in 2012, for all locations with the exception of the Los Angeles River Estuary, in no case shall the time schedule to achieve the final numeric WLAs during dry weather exceed five years from the effective date of the Order”; five years from the effective date of the 2014 City of Long Beach MS4 Permit was March 28, 2019, which is a past deadline. Therefore, the Order requires the City of Long Beach to comply with numeric WQBELs and receiving water limitations during dry weather at the Long Beach City Beaches as of the effective date of the Order.

To determine whether additional time for BMP implementation is appropriate for the Long Beach City Beaches during wet weather conditions, the Los Angeles Water Board considered the factors discussed above along with other considerations such as the time needed to implement BMPs and information on the cost of implementing the BMPs. The Order requires Permittees participating in a WMP to propose a schedule for implementing BMPs to achieve WQBELs and receiving water limitations during wet weather at the Long Beach City Beaches that is as short as possible. Similarly, the Order requires Permittees participating in a WMP to propose a schedule for implementing BMPs to achieve geometric mean WQBELs and receiving water limitations at the Long Beach City Beaches consistent with the schedule proposed to achieve WQBELs and receiving water limitations at the Long Beach City Beaches during wet weather.

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To determine whether additional time for BMP implementation is appropriate for the Los Angeles River Estuary, the Los Angeles Water Board considered the Estuary’s geographic relationship to the Los Angeles River. The Los Angeles River Estuary is downstream of the waterbodies addressed by the Los Angeles Water Board-adopted Los Angeles River Bacteria TMDL.

Therefore, it is appropriate to align implementation schedules for the Los Angeles River Estuary with the compliance schedules for the Los Angeles River Bacteria TMDL. For Permittees participating in a WMP, the Order requires Permittees to propose a schedule for implementing BMPs to achieve WQBELs and receiving water limitations for the Los Angeles River Estuary during dry weather not to exceed the compliance schedule for Segment A (Rosecrans Avenue to Willow Street) in Table Q – 1 of Attachment Q. Table Q-1 of Attachment Q includes dry weather compliance schedules for the Los Angeles River Bacteria TMDL where the schedule for Segment A was deemed most appropriate for the Los Angeles River Estuary. Likewise, for the Los Angeles River Estuary during wet weather, the proposed schedule for implementing BMPs to achieve WQBELs and receiving water limitations in the WMP shall not to exceed the final compliance deadline incorporated in the Order for the Los Angeles River Bacteria TMDL for wet weather (March 23, 2037). Similarly, the Order requires Permittees participating in a Watershed Management Program a to propose a schedule to comply with geometric mean WQBELs and receiving water limitations for the Los Angeles River Estuary consistent with the schedule proposed for wet weather.

Legg Lake System Nutrients TMDL. The Legg Lake System Nutrients TMDL is part of the Los Angeles Area Lakes TMDLs for Nitrogen, Phosphorus, Mercury, Trash, Organochlorine Pesticides and PCBs. Per Table 9-7 and pages 9-18 and 9-19 of the TMDL, the Legg Lake System Nutrients TMDL WLAs for total phosphorus are based on existing MS4 loads at the time of TMDL adoption. However, a load reduction is required to achieve the TMDL WLAs for total nitrogen. Considering that Permittees typically implement the same suite of BMPs to address nutrients, the Los Angeles Water Board determined that it is reasonable for Permittees to be provided with the same compliance options to achieve WQBELs and receiving water limitations for both total nitrogen and total phosphorous. Therefore, the Order incorporates WQBELs and receiving water limitations in Attachment Q consistent with the TMDL WLAs with the option of proposing BMPs and a schedule to implement the BMPs that is as short as possible.

G. Compliance Schedules for Achieving TMDL Requirements A Regional Water Board may include a compliance schedule in an NPDES permit when the state’s water quality standards or regulations include a provision that authorizes such schedules in NPDES permits.209 In California, TMDL programs of implementation210 are typically adopted through amendments to a regional water 209 See In re Star-Kist Caribe, Inc., (Apr. 16, 1990) 3 E.A.D. 172, 175, modification denied, 4 E.A.D. 33, 34 (EAB 1992).
210 TMDL programs of implementation consist of those measures, along with a schedule for their implementation, that the Water Boards determine are necessary to correct an impairment. The NPDES implementation measures are thus required by Clean Water Act sections 303(d) and 402(p)(3)(B)(iii).

State law also requires the Water Boards to implement basin plan requirements. (See Wat. Code §§ 13263, 13377; State Water Resources Control Board Cases (2006) 136 Cal.App.4th 189.)

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board’s basin plan. The TMDL program of implementation, which is part of the basin plan amendment, becomes a regulation upon approval by the State of California Office of Administrative Law (OAL).211 Pursuant to California Water Code sections 13240 and 13242, TMDL programs of implementation adopted by the Regional Water Board “shall include … a time schedule for the actions to be taken [for achieving water quality objectives],” which allows for compliance schedules in future permits. This basin plan amendment becomes the applicable regulation that authorizes an MS4 permit to include a compliance schedule to achieve effluent limitations derived from TMDL WLAs.

Where a TMDL implementation schedule has been established through a basin plan amendment, it is incorporated into the Order as a compliance schedule to achieve interim and final WQBELs and corresponding receiving water limitations, in accordance with 40 CFR section 122.47. WQBELs must be consistent with the assumptions and requirements of any WLA, which includes applicable implementation schedules.212 California Water Code sections 13263 and 13377 state that waste discharge requirements must implement water quality controls plans (i.e., basin plans). 213
Therefore, permit compliance schedules for attaining WQBELs and receiving water limitations derived from WLAs must be based on a state-adopted TMDL programs of implementation and cannot exceed the maximum time that the implementation schedule allows.

In determining the TMDL implementation schedules, the Los Angeles Water Board considered numerous factors to ensure that the schedules are as short as possible.

Factors examined include, but are not limited to, the size and complexity of the watershed; the pollutants being addressed; the number of responsible agencies involved; time for Permittees to negotiate memorandum of agreements; development of water quality management plans; the cost of compliance; identification of funding sources; determination of an implementation strategy based on the recommendations of water quality management plans and/or special studies; and time for the implementation strategies to yield measurable results. Implementation schedules may be altered based on the monitoring and reporting results as set forth in the individual TMDLs by revising the TMDL.

In many ways, the incorporation of interim and final WQBELs, receiving water limitations, and associated compliance schedules is consistent with the inclusion of TMDLs in previous permits in that progress toward compliance with the final effluent limitations may occur over the course of many years. However, because many of the waterbodies in the Los Angeles Region are impaired due to MS4 discharges, it is necessary to establish more specific provisions in order to: (i) ensure measurable reductions in pollutant discharges from the MS4, resulting in progressive water quality 211 See Gov. Code, § 11353, subd. (b). Every amendment to a Basin Plan, such as a TMDL and its program of implementation, requires approval by the State Water Board and OAL. When the TMDL and program of implementation is approved by OAL, it becomes a state regulation. 212 See 40 CFR § 122.44(d)(1)(vii)(B).
213 Cal. Wat. Code, § 13263, subd. (a) (“requirements shall implement any relevant water quality control plans that have been adopted”); Cal. Wat. Code, § 13377 (“the state board or the regional boards shall . . . issue waste discharge requirements and dredged or fill material permits which apply and ensure compliance with all applicable provisions of the [CWA], thereto, together with any more stringent effluent standards or limitations necessary to implement waste quality control plans, or for the protection of beneficial uses, or to prevent nuisance”); see also, State Water Resources Control Board Cases (2006) 136 Cal.App.4th 189.

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improvements, and (ii) establish a final date for completing implementation of BMPs and, ultimately, achieving WQBELs and receiving water limitations.

The compliance schedules established in the Order are consistent with the implementation schedules established in the individual TMDLs. The TMDL implementation deadlines for each TMDL are listed below in Table F-26. As previously noted, TMDLs established by U.S. EPA do not contain implementation schedules.

Unless the Los Angeles Water Board has adopted a separate program of implementation and schedule as a Basin Plan amendment for a U.S. EPA-established TMDL, the implementation date in the table below is the date the TMDL was established by U.S. EPA.

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Table F-26. TMDL Final Implementation Deadlines

TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)

VENTURA RIVER WATERSHED
Ventura River Estuary Trash
TMDL March 6, 2016
TMDL for Algae, Eutrophic Conditions, and Nutrients in the Ventura River and its Tributaries • Wet Weather June 28, 2013
• Dry Weather June 28, 2019

MISCELLANEOUS VENTURA COASTAL WMA
Harbor Beaches of Ventura County (Kiddie Beach and Hobie Beach) Bacteria TMDL • Dry Weather December 18, 2013
• Wet Weather December 18, 2018

SANTA CLARA RIVER WATERSHED
Santa Clara River Nitrogen
Compounds TMDL March 23, 2004
TMDL for Chloride in the Santa
Clara River, Reach 3 (U.S. EPA
established)
June 18, 2003
Upper Santa Clara River Chloride
TMDL April 28, 2015
Santa Clara River Estuary and Reaches 3, 5, 6, and 7 Indicator Bacteria TMDL • Dry Weather March 21, 2023
• Wet Weather March 21, 2029
Lake Elizabeth, Munz Lake, and
Lake Hughes Trash TMDL (Lake
Elizabeth only)
March 6, 2016
Santa Clara River Lakes Nutrients
TMDL (Lake Elizabeth only) June 27, 2032

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)

CALLEGUAS CREEK WATERSHED
TMDL for Organochlorine (OC)
Pesticides, Polychlorinated
Biphenyls (PCBs), and Siltation in
Calleguas Creek, Its Tributaries,
and Mugu Lagoon
March 24, 2026
TMDL for Toxicity, Chlorpyrifos,
and Diazinon in the Calleguas
Creek, its Tributaries, and Mugu
Lagoon
March 24, 2008
TMDL for Metals and Selenium in
Calleguas Creek, its Tributaries,
and Mugu Lagoon
March 27, 2022
Revolon Slough and Beardsley
Wash Trash TMDL March 6, 2016
TMDL for Boron, Chloride,
Sulfate, and TDS (Salts) in the
Calleguas Creek Watershed
December 2, 2023
TMDLs for Pesticides, PCBs, and
Sediment Toxicity in Oxnard Drain
3 (U.S. EPA established)
October 6, 2011

SANTA MONICA BAY WATERSHED
Santa Monica Bay Beaches Bacteria TMDL214
• Summer Dry Weather July 15, 2006
• Winter Dry Weather November 1, 2009
• Wet Weather July 15, 2021
214 The following deadlines for the Santa Monica Bay Beaches Bacteria TMDL are applicable until the effective date of the revised SMB Bacteria TMDL (Attachment A to Resolution No. R21-001).

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
Santa Monica Bay Beaches Bacteria TMDL (Revised)215
• Summer Dry Weather July 15, 2006
• Winter Dry Weather November 1, 2009
• Wet Weather –
Antidegradation Beach Sites July 15, 2021
• Wet Weather – Jurisdictional
Groups 1, 4, 5, 6, and 9 July 15, 2024
• Wet Weather – Jurisdictional
Groups 2 and 3 July 15, 2026
Santa Monica Bay Nearshore and Offshore Debris TMDL216
• Permittees, except
Manhattan Beach March 20, 2020
• Manhattan Beach March 20, 2023
Santa Monica Bay Nearshore and Offshore Debris TMDL (Revised)217 • Permittees, except Hermosa
Beach, Malibu and
Manhattan Beach
March 20, 2020
• Hermosa Beach, Malibu and
Manhattan Beach March 20, 2023
Santa Monica Bay TMDL for
DDTs and PCBs (U.S. EPA
established)
March 26, 2012
215 Upon the effective date of the revised SMB Bacteria TMDL (Attachment A to Resolution No. R21-001), the following deadlines shall be applicable. 216 The following deadlines for the Santa Monica Bay Nearshore and Offshore Debris TMDL (SMB Debris TMDL) are applicable until the effective date of the revised SMB Debris TMDL (Attachment A to Resolution No. R19-004). 217 Upon the effective date of the revised SMB Debris TMDL (Attachment A to Resolution No. R19-004), the following deadlines shall be applicable.

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)

MALIBU CREEK SUBWATERSHED
Malibu Creek and Lagoon Bacteria TMDL218
• Dry Weather January 24, 2012
• Wet Weather July 15, 2021
Malibu Creek and Lagoon Bacteria TMDL (Revised)219
• Dry Weather January 24, 2012
• Wet Weather July 15, 2026
Malibu Creek Watershed Trash
TMDL
July 7, 2017
TMDLs for Nutrients - Malibu Creek Watershed (U.S. EPA established)220 • Los Angeles County
Permittees above Malibou
Lake
December 28, 2021
• Ventura County Permittees
Five years from
effective
date of the Order
TMDLs for Nutrients - Malibu Creek Watershed (U.S. EPA established) (Revised Program of Implementation) 221
• Los Angeles County
Permittees above Malibou
Lake
July 15, 2026
218 The following deadlines for the Malibu Creek and Lagoon Bacteria TMDL (Malibu Creek Bacteria TMDL) are applicable until the effective date of the revised Malibu Creek Bacteria TMDL (Attachment C to Resolution No. R21-001). 219 Upon the effective date of the revised Malibu Creek Bacteria TMDL (Attachment C to Resolution No. R21-001), the following deadlines shall be applicable.
220 The following deadlines for the TMDLs for Nutrients - Malibu Creek Watershed are applicable until the effective date of the revised Implementation Plan for the U.S. EPA-Established Malibu Creek Nutrients TMDL and the U.S. EPA-Established Malibu Creek and Lagoon Sedimentation and Nutrients TMDL to Address Benthic Community Impairments (Implementation Plan for Malibu Creek Nutrients and Sedimentation TMDLs) (Attachment H to Resolution No. R21-001).
221 Upon the effective date of the revised Implementation Plan for Malibu Creek Nutrients and Sedimentation TMDLs (Attachment H to Resolution No. R21-001), the following deadlines shall be applicable.

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
• Ventura County Permittees
Five years from
effective date of the
Order
Malibu Creek and Lagoon TMDL for Sedimentation and Nutrients to Address Benthic Community Impairments (U.S. EPA established)222
• Los Angeles County
Permittees below Malibou
Lake (Nitrogen and
Phosphorus)
December 28, 2023
• Los Angeles County
Permittees below Malibou
Lake (Sediment)
December 28, 2025
Malibu Creek and Lagoon TMDL for Sedimentation and Nutrients to Address Benthic Community Impairments (U.S. EPA established) (Revised Program of Implementation)223
• Los Angeles County
Permittees below Malibou
Lake (Nitrogen and
Phosphorus)
July 15, 2026
• Los Angeles County
Permittees below Malibou
Lake (Sediment)
December 28, 2025

BALLONA CREEK SUBWATERSHED
Ballona Creek Trash TMDL September 30, 2015
222 The following deadlines for the Malibu Creek and Lagoon TMDL for Sedimentation and Nutrients to Address Benthic Community Impairments are applicable until the effective date of the revised Implementation Plan for Malibu Creek Nutrients and Sedimentation TMDLs (Attachment H to Resolution No. R21-001).
223 Upon the effective date of the revised Implementation Plan for Malibu Creek Nutrients and Sedimentation TMDLs (Attachment H to Resolution No. R21-001), the following deadlines shall be applicable.

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
Ballona Creek Estuary Toxic Pollutants TMDL224
• Metals, Total Chlordane and
Total DDTs
January 11, 2021
• Total PCBs January 11, 2025
Ballona Creek Estuary Toxic Pollutants TMDL (Revised)225 • Metals, Total Chlordane,
Total DDTs, and Total PCBs
July 15, 2026
Ballona Creek, Ballona Estuary and Sepulveda Channel Bacteria TMDL226 • Dry Weather April 27, 2013
• Wet Weather July 15, 2021
Ballona Creek, Ballona Estuary and Sepulveda Channel Bacteria TMDL (Revised)227 • Dry Weather April 27, 2013
• Wet Weather July 15, 2026
Ballona Creek Metals TMDL228
• Dry Weather January 11, 2016
• Wet Weather January 11, 2021
Ballona Creek Metals TMDL (Revised)229
• Dry Weather January 11, 2016
224 The following deadlines for the Ballona Creek Estuary Toxic Pollutants TMDL are applicable until the effective date of the revised Ballona Creek Estuary Toxic Pollutants TMDL (Attachment D to Resolution No. R21-001). 225 Upon the effective date of the revised Ballona Creek Estuary Toxic Pollutants TMDL (Attachment D to Resolution No. R21-001), the following deadlines shall be applicable.
226 The following deadlines for the Ballona Creek, Ballona Estuary and Sepulveda Channel Bacteria TMDL (Ballona Creek Bacteria TMDL) are applicable until the effective date of the revised Ballona Creek Bacteria TMDL (Attachment F to Resolution No. R21-001). 227 Upon the effective date of the revised Ballona Creek Bacteria TMDL (Attachment F to Resolution No. R21-001), the following deadlines shall be applicable.
228 The following deadlines for the Ballona Creek Metals TMDL are applicable until the effective date of the revised Ballona Creek Metals TMDL (Attachment G to Resolution No. R21-001).
229 Upon the effective date of the revised Ballona Creek Metals TMDL (Attachment G to Resolution No. R21-001), the following deadlines shall be applicable.

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
• Wet Weather July 15, 2026
Ballona Creek Wetlands TMDL for
Sediments and Invasive Exotic
Vegetation (U.S. EPA
established)
March 26, 2012

MARINA DEL REY SUBWATERSHED
Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL230 • Dry Weather March 18, 2007
• Wet Weather July 15, 2021
Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL (Revised)231 • Dry Weather March 18, 2007
• Wet Weather July 15, 2024
Marina del Rey Harbor Toxic Pollutants TMDL232
• Back Basins D, E and F March 22, 2018
• Front Basins A, B, C, G and
H
March 22, 2021
Marina del Rey Harbor Toxic Pollutants TMDL (Revised)233 • Basins A through H July 15, 2024

DOMINGUEZ CHANNEL AND GREATER HARBORS WATERS WATERSHED
Los Angeles Harbor Bacteria
TMDL (Inner Cabrillo Beach and
Main Ship Channel)
March 10, 2010
230 The following deadlines for the Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL (MdRH Bacteria TMDL) are applicable until the effective date of the revised MdRH Bacteria TMDL (Attachment B to Resolution No. R21-001). 231 Upon the effective date of the revised Marina del Rey Harbor Mothers’ Beach and Back Basins Bacteria TMDL (Attachment B to Resolution No.

R21-001), the following deadlines shall be applicable.
232 The following deadlines for the Marina del Rey Harbor Toxic Pollutants TMDL are applicable until the effective date of the revised Marina del Rey Harbor Toxic Pollutants TMDL (Attachment E to Resolution No. R21-001). 233 Upon the effective date of the revised Marina del Rey Harbor Toxic Pollutants TMDL (Attachment E to Resolution No. R21-001), the following deadlines shall be applicable.

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
Dominguez Channel and Greater
Los Angeles and Long Beach
Harbor Waters Toxic Pollutants
TMDL
March 23, 2032
Machado Lake Trash TMDL March 6, 2016
Machado Lake Eutrophic, Algae,
Ammonia, and Odors (Nutrient)
TMDL
September 11, 2018
Machado Lake Pesticides and
PCBs TMDL September 30, 2019

LOS ANGELES RIVER WATERSHED
Los Angeles River Watershed
Trash TMDL
September 30, 2016
Los Angeles River Nitrogen
Compounds and Related Effects
TMDL
March 23, 2004
Los Angeles River and Tributaries Metals TMDL
• Dry Weather January 11, 2024
• Wet Weather January 11, 2028
Los Angeles River Watershed Bacteria TMDL
• Dry Weather: Segment B –
Alternative Compliance Plan March 23, 2022
• Dry Weather: Segment B –
Load Reduction Strategy
(LRS)
September 23, 2028
• Dry Weather: Segment B
Tributaries – Alternative
Compliance Plan
September 23, 2023
• Dry Weather: Segment B
Tributaries – LRS March 23, 2030

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
• Dry Weather: Segment A –
Alternative Compliance Plan March 23, 2024
• Dry Weather: Segment A –
LRS
September 23,
2031
• Dry Weather: Segment A
Tributary – Alternative
Compliance Plan
September 23, 2025
• Dry Weather: Segment A
Tributary – LRS March 23, 2032
• Dry Weather: Segment E –
Alternative Compliance Plan March 23, 2025
• Dry Weather: Segment E –
LRS
September 23,
2031
• Dry Weather: Segment E
Tributaries – Alternative
Compliance Plan
March 23, 2029
• Dry Weather: Segment E
Tributaries – LRS
September 23,
2035
• Dry Weather: Segment C,
Segment C Tributaries,
Segment D, Segment D
Tributaries – Alternative
Compliance Plan
September 23, 2030
• Dry Weather: Segment C,
Segment C Tributaries,
Segment D, Segment D
Tributaries – LRS
March 23, 2037
• Wet Weather March 23, 2037
Long Beach City Beaches and
Los Angeles River Estuary March 26, 2012

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TOTAL MAXIMUM DAILY
LOADS (TMDLs)
Final
Implementation
Deadline has
passed
Final Implementation
Deadline between years
1 and 5 (2021-2025)
Final
Implementation
Deadline between
years 6 and 10
(2026-2030)
Final
Implementation
Deadline after 10
years (2031 and
onwards)
Bacteria TMDL (U.S. EPA
established)
Legg Lake Trash TMDL March 6, 2016
Los Angeles Area Lakes TMDLs:

Legg Lake System, Lake
Calabasas, Echo Park Lake and
Peck Road Park Lake TMDLS
(U.S. EPA established)
March 26, 2012

SAN GABRIEL RIVER WATERSHED
San Gabriel River and Impaired Tributaries Metals and Selenium TMDL (U.S. EPA established) • Dry Weather September 30, 2023
• Wet Weather September 30, 2026
San Gabriel River, Estuary and Tributaries Indicator Bacteria TMDL • Dry Weather June 14, 2026
• Wet Weather June 14, 2036
Los Angeles Area Lakes TMDLs:

Puddingstone Reservoir Nutrient,
Mercury, Chlordane, Dieldrin,
DDTs and PCBs TMDLs (U.S.

EPA established)
March 26, 2012

LOS CERRITOS CHANNEL AND ALAMITOS BAY WATERSHED
Los Cerritos Channel Metals TMDL (U.S. EPA established) • Dry Weather September 30, 2023
• Wet Weather September 30, 2026
Colorado Lagoon OC Pesticides,
PCBs, Sediment Toxicity, PAHs
and Metals TMDL
July 28, 2018

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H. Considerations Regarding Extensions of TMDL Deadlines Using mechanisms outside of the Order (e.g., Time Schedule Orders, Basin Plan Amendments to revise TMDL implementation schedules), for Los Angeles Water Boardadopted TMDL implementation schedules, the Los Angeles Water Board may consider providing additional time to implement measures to achieve WQBELs and receiving water limitations to more closely align with available funding from the Benefit Assessment Program, Safe, Clean Water Program, and other funding sources available to Permittees as summarized in Part XIII.D.3 of this Fact Sheet (Economic Considerations – Funding Sources).

1. Benefit Assessment Program
On April 14, 1992, the Ventura County Board of Supervisors approved the concept of a countywide NPDES permit program and the use of the Flood Management District (presently the Watershed Protection District) benefit assessment authority to finance it. On June 30, 1992, the Ventura County Board of Supervisors adopted a benefit assessment fee for stormwater and flood management in the unincorporated areas of Ventura County and the cities within the County, to be used in part to finance the implementation of a countywide NPDES municipal stormwater permit program. The Ventura County Permittees except for the City of Moorpark entered into an agreement with the Watershed Protection District to finance the activities related to the Ventura County MS4 Permit for shared and district-wide expenses. The Permittees are also given the option to use the Benefit Assessment Program to finance their respective activities related to reducing the discharge of pollutants from their MS4s under the MS4 Permit.

2. Safe, Clean Water Program
In November 2018, Los Angeles County voters approved Measure W, adopting the Safe, Clean Water Program, which will generate up to $285 million per year from a special parcel tax on private property to capture, conserve, and treat stormwater to improve water quality, increase local water supply, and enhance communities.

The County began dispersing revenues from the collected taxes. (See, Table F-20) The Safe, Clean Water Program will be reevaluated in 30 years. Fifty percent of the Safe, Clean Water Program funds will be allocated to the “Regional Program”, which will consist of projects and programs at the watershed scale to address stormwater from multiple municipalities. As of August 2020, the current projected revenue for the Regional Program is $140.6 million per year. Forty percent of the funds will be allocated directly to municipalities as part of the “Municipal Program” for local stormwater projects and programs. As of August 2020, the current projected revenue for the Municipal Program is $112.6 million per year. Ten percent of the Safe, Clean Water Program funds will be allocated to the “District Program” for general administration of the program including, but not limited to, technical assistance teams, watershed coordinators funded through the Regional Technical Resources Program (TRP), stormwater education programs, and District Projects.

The Los Angeles Water Board may decide to extend deadlines based on availability and distribution of Safe, Clean Water Program funding and other dedicated funding sources, on the funding allocation schemes contained in the Stormwater Investment Plans developed by each Watershed Area Steering Committee for the Regional Program funds, and funding allocations in the fiscal year plans developed by each municipality for the Municipal Program funds. Based

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on a comparison of the locations of prioritized projects and those waterbodies with upcoming deadlines, the Los Angeles Water Board can determine if additional time is warranted to allow for Safe, Clean Water Program revenues to accrue to fund in part or total the projects needed to comply with WQBELs and receiving water limitations.

VII. RATIONALE FOR RECEIVING WATER LIMITATIONS
Clean Water Act section 402(p)(3)(B)(iii) requires MS4 permits to include “such other provisions as the Administrator or the State determines appropriate for the control of [] pollutants.” U.S. EPA interprets this provision to mandate “controls to reduce the discharge of pollutants to the maximum extent practicable, and where necessary water quality-based controls.”234 U.S. EPA has reiterated that MS4 “permit conditions must provide for attainment of applicable water quality standards (including designated uses), allocations of pollutant loads established by a TMDL, and timing requirements for implementation of a TMDL.”235 U.S. EPA Region IX has also affirmed the agency’s position that MS4 discharges must meet water quality standards in a series of comment letters on MS4 permits issued by various California regional water boards.236 Likewise, the State Water Board has affirmed that MS4 permits must include requirements necessary to achieve compliance with the applicable technology-based standard of MEP and to achieve water quality standards.237 The permitting agency, be it the Los Angeles Water Board or U.S. EPA, must therefore include provisions when it finds it is appropriate to do so to control pollutants in a specific geographic area.

California Water Code section 13377 also requires that NPDES permits include limitations necessary to implement water quality control plans. Both the State Water Board and Los Angeles Water Board have previously concluded that discharges from the MS4 contain pollutants that have the reasonable potential to cause or contribute to excursion above water quality standards. As such, inclusion of receiving water limitations is necessary and appropriate to control MS4 discharges in the Los Angeles Region.

The inclusion of receiving water limitations is also consistent with the Ninth Circuit Court of Appeal’s ruling in Defenders of Wildlife v. Browner (191 F.3d 1159, 1166 (1999)) that the permitting authority has discretion regarding the nature and timing of requirements that it includes as MS4 permit conditions to attain water quality standards.

The Ninth Circuit Court of Appeals has explained that, “[w]ater quality standards are used as a supplementary basis for effluent limitations [guidelines] so that numerous dischargers, despite their individual compliance with technology based effluent limitations, can be regulated to prevent water quality from falling below acceptable levels” (NRDC v. County of Los Angeles (2011) 673 F.3d 880, 886). Receiving water limitations are included in the Order to ensure that individual and collective discharges from the MS4 do not cause or contribute to exceedances of water quality standards necessary to protect the beneficial uses of the receiving waters.

The receiving water limitations in the Order consist of all applicable numeric or narrative water quality objectives or criteria, or limitations to implement the applicable water quality 234 Phase I Stormwater Regulations, Final Rule, 55 Fed. Reg. 47990, 47994 (Nov. 16, 1990) (emphasis added); see also Building Industry Ass’n of San Diego County v. State Water Resources Control Bd. (2004) 124 Cal.App.4th 866, 882-887).
235 See, e.g., Phase II Stormwater Regulations, Final Rule, 64 Fed. Reg. 68722, 68737. 236 See, e.g., letter from Alexis Strauss, Acting Director, Water Division, U.S. EPA Region IX, to Walt Pettit, Executive Director, State Water Board, re: SWRCB/OCC File A-1041 for Orange County, dated January 21, 1998.
237 See, e.g., State Water Board Orders WQ 99-05, WQ 2001-15, and WQ 2015-0075.

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objectives or criteria, for receiving waters as contained in Chapters 3 and 7 of the Basin Plan, or in water quality control plans or policies adopted by the State Water Resources Control Board, including Resolution No. 68-16, or in federal regulations, including but not limited to, 40 CFR sections 131.12 and 131.38. The water quality objectives in the Basin Plan and other State Water Board plans and policies have been approved by U.S. EPA and combined with the designated beneficial uses and the state’s antidegradation policy constitute the water quality standards required under federal law.

The receiving water limitations provisions in the Order are carried over from the previous permits and are based on precedential State Water Board Orders WQ 98-01, WQ 99-05, and WQ 2015-0075. In Order 99-05, the State Water Board directed that all MS4 permits contain specific language explaining how receiving water limitations will be implemented.

Since 2001, the Los Angeles Water Board has included this language in all MS4 permits.

After re-examining the receiving water limitations and iterative process in MS4 permits statewide, in 2015, the State Water Board proclaimed the following:

As the storm water management programs of municipalities have matured, an increasing body of monitoring data indicates that many water quality standards are in fact not being met by many MS4s. The iterative process has been underutilized and ineffective to date in bringing MS4 discharges into compliance with water quality standards. Compliance with water quality standards is and should remain the ultimate goal of any MS4 permit. We reiterate and confirm our determination that provisions requiring compliance with receiving water limitations are “appropriate for the control of . . . pollutants” addressed in MS4 permits and that therefore, consistent with our authority under the Clean Water Act, we will continue to require compliance with receiving water limitations. (Order WQ 2015-0075, p. 14.)
Having determined that it will not depart from its prior precedent regarding compliance with water quality standards, the State Water Board directed that the “regional water boards shall continue to require compliance with receiving water limitations in municipal storm water permits through incorporation of receiving water limitations provisions consistent with State Water Board Order WQ 99-05.” (Id., p. 76.)
Thus, consistent with State Water Board Order 99-05, the Order includes three main provisions related to receiving water limitations. First, consistent with CWA section 402(p)(B)(3)(iii) and 40 CFR section 122.44(d)(1), it includes a provision stating that discharges from the MS4 that cause or contribute to an exceedance of receiving water limitations are prohibited. This is also in accord with the State Water Board’s finding in Order WQ 98-01 (“The [State Water Board] agrees that the NPDES permit must prohibit discharges that “cause” or “contribute” to violations of water quality standards.”). Second, it includes a provision stating that discharges from the MS4 of stormwater or non-stormwater, for which a Permittee is responsible, shall not cause or contribute to a condition of nuisance.238 Third, it includes a provision that states that Permittees shall achieve these two prohibitions “through timely implementation of control measures and other actions to reduce pollutants in the discharges in accordance with the storm water management program and its components and other requirements of this Order including any modifications.” This third provision elucidates the process by which Permittees are expected to achieve the first two provisions and then outlines the so-called “iterative process” whereby certain actions are 238 Wat. Code, § 13377 (“the state board or the regional boards shall . . . issue waste discharge requirements and dredged or fill material permits which apply and ensure compliance with all applicable provisions of the [CWA], thereto, together with any more stringent effluent standards or limitations necessary to implement waste quality control plans, or for the protection of beneficial uses, or to prevent nuisance”).

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required when exceedances of receiving water limitations occur and discharges from the MS4 are implicated. This iterative process includes submitting a Receiving Water Limitations Compliance Report; revising the stormwater management program and its components to include additional BMPs, an implementation schedule and additional monitoring to address the exceedances; and implementing the revised stormwater management program. The inclusion of this protocol for estimating BMP effectiveness and taking additional actions such as implementing additional BMPs and/or modifying BMPs to improve their effectiveness when monitoring demonstrates that they are necessary to protect water quality is consistent with U.S. EPA’s expectations for MS4 permits.239
The State and Los Angeles Water Boards have stated that each of the three provisions are independently applicable, meaning that compliance with one provision does not provide a “safe harbor” where there is non-compliance with another provision (i.e., compliance with the third provision does not shield a Permittee who may have violated the first or second provision from an enforcement action). Rather, the third provision is intended to ensure that the necessary stormwater management programs and controls are in place, and that they are modified by Permittees in a timely fashion when necessary, so that the first two provisions are achieved as soon as possible. U.S. EPA expressed the importance of this independent applicability in a series of comment letters on MS4 permits proposed by various regional water boards. At that time, U.S. EPA expressly objected to certain MS4 permits that included language stating, “permittees will not be in violation of this [receiving water limitation] provision …[if certain steps are taken to evaluate and improve the effectiveness of the Drainage Area Management Plan (DAMP)],” concluding that this phrase would not comply with the CWA.240
The Receiving Water Limitations provisions of the 2001 Los Angeles County MS4 permit (Order No. 01-182) have been litigated twice, and in both cases the courts have upheld the language and the State and Los Angeles Water Boards’ interpretation of it. Both courts ruled that the first two provisions are independently applicable from the third provision that establishes the “iterative process” requirements and no “safe harbor” exists.

The provisions were first litigated in 2005 where the Los Angeles County Superior Court stated, “In sum, the Regional [Water] Board acted within its authority when it included Parts

2.1 and 2.2 in the Permit without a ‘safe harbor,’ whether or not compliance therewith requires efforts that exceed the ‘MEP’ standard.” (In re L.A. Cnty. Mun. Storm Water Permit Litig. (L.A. Super. Ct., No. BS 080548, Mar. 24, 2005) Statement of Decision from Phase I Trial on Petitions for Writ of Mandate, pp. 4-5, 7.) The Court of Appeal upheld the 2001 Los Angeles County MS4 Permit. (County of Los Angeles et al. v. California State Water Resources Control Board et al. (2006) 143 Cal.App.4th 985).

The provisions were again litigated in 2011. In that case, the Ninth Circuit Court of Appeals in NRDC v. County of Los Angeles (673 F.3d 880, 886) affirmed that the iterative process (in Part 2.3 of Order No. 01-182) does not “forgive” violations of the discharge prohibitions (in Parts 2.1 and 2.2 of Order No. 01-182). The court acknowledged that Part 2.3 clarifies that Parts 2 and 3 interact, but the court concluded that Part 2.3 “offers no textual support for the proposition that compliance with certain provisions shall forgive non-compliance with the 239 See, e.g., U.S. EPA 2014 memorandum, “Revisions to the November 22, 2002 Memorandum ‘Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs’” dated November 26, 2014. 240 See, e.g., letter from Alexis Strauss, Acting Director, Water Division, USEPA Region IX, to Walt Pettit, Executive Director, State Water Board, re: SWRCB/OCC File A-1041 for Orange County, dated January 21, 1998.

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discharge prohibitions.” The Ninth Circuit further concluded that, “[a]s opposed to absolving noncompliance or exclusively adopting the MEP standard, the iterative process ensures that if water quality exceedances ‘persist,’ despite prior abatement efforts, a process will commence whereby a responsible Permittee amends its SQMP. Given that Part 3 of the [2001] Permit states that SQMP implementation is the ‘minimum’ required of each Permittee, the discharge prohibitions serve as additional requirements that operate as enforceable water-quality-based performance standards required by the Regional Board.” Additionally, in 2015, the State Water Board specifically addressed the issue of whether compliance with the “iterative process” in part 3 constituted compliance with parts one and two of the receiving water limitation provisions in precedential State Water Board Order WQ 2015-0075 (concerning the 2012 Los Angeles MS4 Permit). 241 Given “significant confusion”
amongst permittees, the State Water Board clarified once again that compliance with the “iterative process” is not a “safe harbor” and that MS4 discharges that are causing or contributing to an exceedance of water quality standards are in violation of the permit.242 The State Water Board also expressly rejected arguments that State Water Board Order WQ 2001-15 stands for the proposition that the iterative process is a “safe harbor.” 243 VIII. RATIONALE FOR STANDARD PROVISIONS
Standard Provisions incorporated in the Order have been carried over from the previous MS4 permits.

A. Standard Provisions
Standard Provisions, which apply to all NPDES permits in accordance with 40 CFR section 122.41, and additional conditions applicable to specified categories of permits in accordance with 40 CFR section 122.42, are provided in Attachment D. Dischargers must comply with all standard provisions and with those additional conditions that are applicable under section 122.42.

B. Legal Authority
A Permittee must have adequate legal authority to implement its stormwater management program, including minimum control measures, and all equivalent actions if implemented through a Watershed Management Program (see 40 CFR section 122.26(d)(2)(i)(A)-(F) and 40 CFR section 122.26(d)(2)(iv)). Without adequate legal authority, the Permittee would be unable to perform many functions such as performing inspections, requiring remedies, and requiring installation of control measures. In addition, the Permittee would not be able to conduct enforcement, where necessary.

Additionally, pursuant to 40 CFR sections 122.26(d)(1)(ii) and 122.26(d)(2)(iv), each Permittee must also maintain the necessary legal authority to control the contribution of pollutants to its MS4 and must include in its stormwater management program a comprehensive planning process that includes intergovernmental coordination, where necessary. As noted elsewhere, federal, state, regional or local entities not named as a Permittee in the Order may operate MS4 facilities and/or discharge to the Permittees’ MS4s and water bodies covered by the Order (e.g., California Department of Transportation). The abovementioned requirement is intended to address, in part, these circumstances.
241 See generally discussion pages 10-12 of State Board Order WQ 2015-0075. 242 Id. at 12.
243 Id. at p. 12, fn. 44.

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C. Fiscal Resources
Section 122.26(d)(2)(vi) of Title 40 of the Code of Federal Regulations requires, for each fiscal year to be covered by the permit, a fiscal analysis of the necessary capital and operation and maintenance expenditures necessary to accomplish the activities of the stormwater management program, including monitoring program. The analysis is to include a description of the source(s) of funds that are proposed to meet the necessary expenditures, including legal restrictions on the use of such funds. Additionally, 40 CFR section 122.42(c)(5) requires that annual reports for MS4 permits include annual expenditures and budget for year following each annual report. The inclusion of the requirement to perform a fiscal analysis annually in the Regional MS4 Permit was carried over from the previous permits. The annual fiscal analysis will show the allocated resources, expenditures, and staff resources necessary to comply with the Regional MS4 Permit, including implementation of the Permittee’s Watershed Management Program, where applicable. The annual analysis is necessary to show that the Permittee has adequate resources to meet all Permit requirements. The analysis can also show year-to-year changes in funding for the MS4 program. A summary of the annual analysis must be reported in the annual report. This analysis will help the Los Angeles Water Board understand the resources that are dedicated to compliance with this permit including the implementation of Watershed Management Programs, and track how costs change over time. Permittees will provide their annual fiscal analysis in Attachment H (Annual Report Form) of the Order. Attachment H of the Order identifies a consistent reporting format for this fiscal analysis as recommended by the State Auditor in its Report 2017-118 on the State and Regional Water Boards MS4 programs.

This reporting format is based on the statewide guidance, “Guidance for Obtaining Phase I Municipal Separate Storm Sewer System Permit (MS4) Compliance Costs,” prepared by the State Water Board in response to the State Auditor’s recommendation.244
D. Responsibilities of the Permittees
Because of the complexity and networking of the storm drain system and drainage facilities within the Los Angeles Region, the Los Angeles Water Board adopted a regionwide approach in permitting stormwater and urban runoff discharges. (See Part I.D of this Fact Sheet) Note that the 2010 Ventura County MS4 Permit was structured to assign certain requirements to the Principal Permittee (Ventura County Watershed Protection District) and other requirements to the other Ventura County Permittees. As this is a Regional MS4 Permit and applies to both Los Angeles County and Ventura County MS4 Permittees, the retention of a Principal Permittee as discussed in Part II.D of this Fact Sheet is no longer applicable. Accordingly, there are no separate requirements for the Principal Permittee in the Regional MS4 Permit. Consistent with the previous permits, the Regional MS4 Permit is structured to require all Permittees to comply with the requirements of the Order as applicable to its discharges. However, it does not hold a Permittee responsible for implementation of provisions applicable to other Permittees. Note that, in some cases, the Order includes specific requirements for Los Angeles County Permittees and others for Ventura County Permittees and, in some cases, the Order includes specific requirements for the two flood control districts. These cases are clearly indicated in the Order.
244 State Water Resources Control Board (2020) “Guidance for Obtaining Phase I Municipal Separate Storm Sewer System Permit (MS4) Compliance Costs.” August 12, 2020.

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Parts VI.D.4-5 of the Order requires inter- and intra-agency coordination to facilitate implementation of the Order. This requirement is based on 40 CFR section 122.26(d)(2)(iv), which requires “a comprehensive planning process which involves public participation and where necessary intergovernmental coordination, to reduce the discharge of pollutants to the maximum extent practicable using management practices, control techniques and system, design and engineering methods, and such other provisions which are appropriate […].”
E. Public Review and Los Angeles Water Board Review
Public review and Los Angeles Water Board review provisions have been carried over from the previous permits. These provisions reflect federal and state requirements to make documents available to members of the public pursuant to the Freedom of Information Act (5 U.S.C. § 552 (as amended)) and the Public Records Act (Cal.

Government Code § 6250 et seq.). They also reflect the Los Angeles Water Board’s commitment to public participation during implementation of the Regional MS4 Permit.

F. Reopener and Modification Provisions
These provisions are based on 40 CFR sections 122.44, 122.62, 122.63, 122.64, 124.5, 125.62, and 125.64, and are also carried over from the previous permits. The Los Angeles Water Board may reopen the permit to modify permit conditions and requirements, as well as revoke, reissue, or terminate in accordance with federal regulations. Causes for such actions include, but are not limited to, endangerment to human health or the environment; acquisition of newly-obtained information that would have justified the application of different conditions if known at the time of Order adoption; to incorporate provisions as a result of new federal or state laws, regulations, plans, or policies (including TMDLs and other Basin Plan amendments); modification in toxicity requirements; violation of any term or condition in the Order; and/or minor modifications to correct typographical errors or require more frequent monitoring or reporting by a Permittee. The Order also includes two additional causes for modification, which have been carried over from prior permits, including: 1) where the revisions warrant a change to the provisions of the Order, the Los Angeles Water Board may modify the Order consistent with the assumptions and requirements of the revised WLA(s), including the program of implementation and schedule; and 2) to include provisions or modifications to WQBELs in Part IV and Attachments K-S in the Order prior to the final compliance deadlines, if practicable, that would allow an action-based, BMP compliance demonstration approach with regard to final WQBELs for stormwater discharges based on the Los Angeles Water Board’s evaluation of whether Watershed Management Programs in Part VI.C of the Order have resulted in attainment of interim WQBELs for stormwater and review of relevant research, including but not limited to data and information provided by Permittees and other stakeholders, on stormwater quality and the efficacy and reliability of control technologies.

G. Other Provisions
Other provisions in the Standard Provisions of the Order not specifically discussed above were carried over from the previous permits.

IX. RATIONALE FOR STORMWATER MANAGEMENT PROGRAMS AND MCMs The required components of stormwater management programs and minimum control measures (MCMs) are specifically set forth in Part VIII.D through Part VIII.I of the Order.

However, each of these six Parts have several overlapping requirements (including timelines

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for implementation, municipal employee and contractor training and progressive enforcement), which are addressed in Part VIII.A through Part VIII.C of the Order.

A. General Requirements

1. Basis for Minimum Control Measures (MCMs)
40 CFR section 122.26(d)(2)(iv) establishes required elements of the Permittees’ stormwater management program. The previous permits included six categories of minimum control measures (or MCMs) that are the baseline programmatic elements for meeting the requirements of 40 CFR section 122.26(d)(2)(iv). The minimum control measures require Permittees to implement BMPs that are considered necessary to reduce pollutants in stormwater to the MEP and to effectively prohibit non-stormwater discharges. In lieu of implementing the MCMs as described in Part VIII.A.1 of the Order, the Order allows Permittees to develop alternative BMPs to comply with 40 CFR section 122.26(d)(2)(iv) when implemented through a Watershed Management Program approved by the Los Angeles Water Board.

2. Timelines for Implementation
The timelines for implementation of MCMs are specified in Part VIII.A.2 of the Order where all Permittees must implement the MCMs no later than 6 months from the effective date of the Order or per specific timelines indicated in the Order. If participating in a Watershed Management Program, the MCMs are required to be integrated in the new or revised Watershed Management Program. Since Permittees have been implementing MCMs in the previous permits, they are expected to continue implementing their MCMs. Ventura County Permittees that elect to develop a Watershed Management Program shall continue to implement their existing stormwater management programs, including actions within each of the six categories of minimum control measures consistent with 40 CFR section 122.26(d)(2)(iv) until the Watershed Management Program is approved by the Los Angeles Water Board. Likewise, Los Angeles County Permittees that opt to continue implementing an approved Watershed Management Program shall continue to implement the six categories of MCMs as approved in their Watershed Management Program until any revision to their Watershed Management Program is approved by the Los Angeles Water Board.

3. Municipal Employee and Contractor Training
Municipal training requirements are necessary to implement CWA section 402(p)(3)(B)(ii) and (iii). The Los Angeles Water Board finds that specifying training requirements for municipal employees and contractors is necessary to prevent or minimize the potential discharge of pollutants through the MS4 to receiving waters as explained in the following paragraphs. Municipal employees whose jobs affect stormwater quality must be trained in stormwater management to ensure that nonstormwater discharges are effectively prohibited, the discharge of pollutants in stormwater is reduced to the maximum extent practicable, and other provisions to control pollutants in MS4 discharges are implemented as required. The Order retains municipal employee and contractor training requirements from the previous Los Angeles County, City of Long Beach, and Ventura County permits. Note that the previous permits included training requirements within each MCM. Specific requirements were included in the Public Agency Activities MCM, Illicit Connection and Illicit Discharge MCM, Construction MCM, and Planning and Land

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Development MCM. For better organization, the Order includes these provisions under the General Provisions in Part VIII.A of the Order where training requirements apply to all municipal employees and contractors implementing the stormwater management program and includes specific training requirements for the Illicit Discharge Detection and Elimination (IDDE), Construction, and Industrial/Commercial Facilities MCMs.

U.S. EPA’s MS4 Permit Improvement Guide supports the conclusion that municipal employee and contractor training requirements are necessary to meet federal requirements. U.S. EPA states, “[f]ederal stormwater regulations (see 40 C.F.R. 122.34(b)(6) and 40 C.F.R. 122.26(d)(2)(iv)(A)) require the operator of a regulated MS4 community to develop a program to… [t]rain employees on how to incorporate pollution prevention/good housekeeping techniques into municipal operations.”245 The Guide includes example permit provisions that state, “[p]ermittees must develop an annual training program for appropriate employees involved in implementing pollution prevention and good housekeeping practices in the preceding Parts” and “[t]he permittee must provide oversight of contractor activities to ensure that contractors are using appropriate control measures and [standard operating procedures].”246 U.S. EPA also provides several examples of permits with similar training requirements.247 Moreover, U.S. EPA-issued MS4 permits commonly include pollution prevention training requirements for municipal staff.248,249,250
Federal regulations identify the need for a program to reduce pollutants in discharges from MS4s associated with the application of pesticides, herbicides, and fertilizer.251 Training programs for the application of pesticides and fertilizer are necessary to comply with these regulations. A municipal training program addresses these federal requirements, in part, by including “certifications and other measures for commercial applicators and distributors.” Federal regulations for small MS4s explicitly outline the requirement for permits to include training provisions:
“The permit must identify the minimum elements and require the development and implementation of an operation and maintenance program that includes a training component and has the ultimate goal of preventing or reducing pollutant runoff from municipal operations. Using training materials that are available from EPA, the State, Tribe, or other organizations, the program must include employee training to prevent and reduce storm water pollution from activities such as park and open space maintenance, fleet and building 245 U.S. EPA. MS4 Improvement Guide (2010), pp. 67, 83. 246 Id., at p. 84.
247 Compendium of MS4 Permitting Examples, Part 1: Six Minimum Control Measures. Office of Wastewater Management, Water Permits Division. November 2016. 810-U-16-001. 248 Maryland Department of the Environment, National Pollutant Discharge Elimination System Municipal Separate Storm Sewer System Discharge Permit, NPDES No. MD0068276, Effective October 9, 2015. p. 6. 249 NPDES permit (DC0000221) issued to Government of the District of Columbia, with final signed Modification #1, effective November 9, 2012. pp. 20-21. 250 NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. p. 26 and 29.
251 40 CFR § 122.26(d)(2)(iv)(A)(6).

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maintenance, new construction and land disturbances, and storm water system maintenance.”252
Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(6) require a description of educational activities, public information activities, and other appropriate activities to facilitate the proper management and disposal of used oil and toxic materials. The Order requires each Permittee to train field staff who may come into contact or observe illicit discharges on the identification and proper procedures for responding to and reporting illicit discharges. The previous Los Angeles County, City of Long Beach, and Ventura County permits had similar requirements.

Municipal maintenance and repair activities are frequently conducted in areas where illicit connections and discharges occur. Therefore, municipal employees who are not assigned specifically to implement a municipality’s illicit discharge detection and elimination (IDDE) program are often good resources for reporting illicit connections and discharges.

The U.S. EPA MS4 Permit Improvement Guide states that, “Phase I MS4 regulations specify that several key elements be included in Phase I MS4 stormwater management programs [to control pollutants in stormwater discharges to the MS4 from industrial and commercial facilities]. These elements include:
adequate legal authority to require compliance and inspect sites, inspection of priority industrial and commercial facilities, establishing control measure requirements for facilities that may pose a threat to water quality, and enforcing stormwater requirements. In order to implement these requirements, MS4 permits require the development of an inventory of facilities and prioritization protocol and adequate staff training to ensure proper inspection and enforcement of requirements.”253
40 CFR section 122.26(d)(2)(iv)(D)(4) requires that Permittees have appropriate educational and training measures for construction site operators.254 More specifically, 40 CFR section 122.26(d)(2)(iv)(D)(3) requires that Permittees have “procedures for identifying priorities for inspecting sites and enforcing control measures…”. An important element of such procedures is training for the individuals tasked with implementing the program. Therefore, the municipal employees and contractors training requirement in the Order is necessary to meet these federal requirements, by ensuring that Permittees are trained in technical standards for BMPs and that they make these technical standards readily available to the development community as educational and training measures. The U.S.

EPA MS4 Permit Improvement Guide provides draft permit provisions that closely resemble the requirements for municipal employees and contractor training in the Order, including training for staff as well as third-party inspectors and plan reviewers.255
B. Progressive Enforcement
Progressive enforcement is a series of defined and reproducible enforcement actions whereby consequences of non-compliance increase with each incremental enforcement step. Progressive enforcement includes procedures to coordinate enforcement between the Los Angeles Water Board and Permittees. As the Los Angeles Water Board is the 252 Id., § 122.34(b)(6)(i).
253 U.S. EPA. MS4 Permit Improvement Guide (2010), Chapter 7, p. 85 (emphasis added). 254 Id., subd. (d)(2)(iv)(D)(4).
255 U.S. EPA. MS4 Permit Improvement Guide (2010), Chapter 4, p. 46.

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regulating agency for the NPDES program, it has the authority to step in when enforcement actions of a Permittee are unsuccessful in bringing dischargers into compliance. As such, progressive enforcement is an effective strategy to achieve timely compliance. Previous permits included requirements for Permittees to develop and implement a progressive enforcement strategy, which are carried over to the Order. The Order eliminates the provision in the 2010 Ventura County MS4 Permit that allows the Los Angeles Water Board and Permittees to form a stormwater task force. This provision was removed because the ability for coordinated enforcement between the Los Angeles Water Board and Permittees is adequately established through remaining provisions within Part VIII.B of the Order. Also note that the 2010 Ventura County MS4 Permit includes progressive enforcement requirements within the Industrial/Commercial Facilities MCM and Construction MCM. However, the Progressive Enforcement provisions under Part VIII.B of the Order follow the same structure of the 2012 Los Angeles County and 2014 City of Long Beach MS4 permits and are inclusive of the progressive enforcement requirements that were previously within the two abovementioned MCMs in the 2010 Ventura County MS4 Permit.

C. Modifications/Revisions
The Order requires each Permittee to modify its stormwater management programs, protocols, practices, and municipal codes to be consistent with the Order. This provision is necessary to ensure that each Permittee takes all the steps necessary to update the core and ancillary programs that are required to ensure compliance with the Order.

D. Public Information and Participation Program

1. Federal Requirements
The Los Angeles Water Board has incorporated the Public Information and Participation Program into the Regional MS4 Permit per the following federal requirements:

Clean Water Act section 402(p)(3)(B)(iii) requires that “[p]ermits for discharges from municipal storm sewers shall require controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants.”
NPDES regulations at 40 CFR section 122.26(d)(2)(iv) require as part of a stormwater management program “a comprehensive planning process which involves public participation and where necessary intergovernmental coordination, to reduce the discharge of pollutants to the maximum extent practicable using management practices, control techniques and system, design and engineering methods, and such other provisions which are appropriate.” NPDES regulations at 40 CFR section 122.26(d)(2)(iv)(A)(6) provide that the proposed management program include “[a] description of a program to reduce to the maximum extent practicable, pollutants in discharges from MS4s associated with the application of pesticides, herbicides, and fertilizer which will include, as appropriate, controls such as educational activities, permits, certifications, and other measures for commercial applicators and distributors, and controls for application in public right-of-way’s and at municipal facilities.”

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NPDES regulations at 40 CFR section 122.26(d)(2)(iv)(B)(6) provide that the proposed management program includes “[a] description of education activities, public information activities, and other appropriate activities to facilitate the proper management and disposal of used oil and toxic materials.” 40 CFR section 122.42(c) requires the owner or operator of an MS4 to submit an annual report that includes in part “(1) The status of implementing the components of the storm water management program that are established as permit conditions; (2) Proposed changes to the storm water management programs that are established as permit condition. Such proposed changes shall be consistent with §122.26(d)(2)(iii) of this part…” and “(6) A summary describing the number and nature of enforcement actions, inspections, and public education programs; …”

2. General Provisions
Part VIII.D.1 of the Order requires continued implementation of public participation in the stormwater management program, consistent with 40 CFR section 122.26(d)(2)(iv). It is generally more cost-effective to have multiple Permittees coordinate using an existing program than have each individual Permittee develop its own local program. Therefore, Permittees are encouraged to participate in a County-wide public information and participation program (PIPP) or in one or more Watershed Group sponsored PIPPs supplemented with additional information specific to local needs. While the previous 2010 Ventura County MS4 Permit required coordination among Permittees, this Regional Permit covers numerous Permittees over a larger area, making it difficult to coordinate amongst all Permittees. As a result, the Los Angeles Water Board encourages but does not require forming partnerships and coordination among Permittees. This is consistent with by 40 CFR §§122.26(d)(2)(iv), which specifies intergovernmental coordination as part of the stormwater management program where necessary.

Previous 2012 Los Angeles County and 2010 City of Long Beach MS4 permits required the Public Information and Participation Program to include contact information and means for public reporting of clogged catch basin inlets, illicit discharges/dumping, faded or missing catch basin labels, and general stormwater and non-stormwater pollution prevention information. These requirements are redundant with requirements in the Illicit Discharge Detection and Elimination Program and are removed from the Public Information and Participation section.

3. Objectives
The objectives of the PIPP are to involve and engage a diversity of socioeconomic groups and ethnic communities by building an understanding of stormwater issues and strengthening support for programs and projects. These objectives are established in the permit to provide a compass for Permittees as they adapt their program to address new information, water quality priorities, and MS4 program priorities. Through broad community support, the program objective in Part VIII.D.2 of the Order would instill the methods for proper management and disposal of used oil and toxic materials such that pollution prevention becomes common knowledge in the community.

The Order also includes an objective to use effective strategies to educate and involve residents and population subgroups through culturally effective methods.

To accomplish this objective, Permittees may rely on the existing framework of their program and build upon existing methods to reach cultural subgroups. For

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example, existing materials may be translated to other languages or recurring events may be promoted through television and radio stations that cater to specific subgroups.

The objectives in the Regional MS4 Permit support the broader federal requirements discussed earlier in this Fact Sheet by encouraging behavior changes that reduce pollutants in stormwater and non-stormwater. The programs must reach the general population, but also must reach a portion of the population who might otherwise be overlooked. U.S. EPA support for this provision is evident in a similar provision in the U.S. EPA-issued permit for the Middle Rio Grande Watershed.
256 In addition, U.S. EPA, Tailoring Outreach Programs to Minority and Disadvantaged Communities and Children Fact Sheet257 finds that, "[m]any residents of ethnically and culturally diverse communities don't speak English.” English messages contained in public education outreach materials may not be effectively reaching a significant portion of some communities. In addition, some lower income communities may have less access to the internet and would be more reachable through TV, radio, and neighborhood newspapers than through webpages.
258

4. Program Requirements
a. Community involvement in stormwater planning and program implementation and awareness of stormwater program needs (Part VIII.D.3.a of the Order).

An emerging challenge for municipal stormwater programs is to promote the public’s understanding for the need for planning and funding of stormwater programs and projects. Stormwater programs are a key component of water quality protection and are a legal requirement. By educating and involving the public on stormwater planning needs, municipalities may gain public support for funding stormwater programs. Through stakeholder input, the Los Angeles Water Board recognizes that a lack of support in planning and funding are often obstacles to effective program implementation. This requirement is supported by the U.S. EPA Memorandum dated October 26, 2016 that identifies lack of funding as a limiting factor in implementing stormwater pollution programs. The memorandum further recommends long-term planning to secure adequate funding for infrastructure and stormwater controls. Public awareness of long-term planning and implementation is therefore a necessary step towards gaining support and funds for short-term and long-term program implementation. First step methods for involving the community may include town meetings, webinars, citizen advisory committees or focus groups. Once community support is strengthened, the Permittee may also develop and promote ballot funding measures for stormwater projects and thus meet several PIPP requirements and achieve program objectives. 256 NPDES Permit No. NMR04A000 issued to Middle Rio Grande Watershed, effective December 22, 2014. p. 48.
257 U.S. EPA. 2006. "Tailoring Outreach Programs to Minority and Disadvantaged Communities and Children." National Pollutant Discharge Elimination System (NPDES). May 24, 2006. As noted on the website https://www.epa.gov/npdes/national-menu-best-management-practices-bmps-stormwater#edu, U.S. EPA is currently updating this document.
258 See Internet/Broadband Fact Sheet. Pew Research Center, Internet and Technology. The center displays data showing lower internet use among non-white ethnic groups and lower income groups. http://www.pewinternet.org/fact-sheet/internet-broadband/. Accessed on May 11, 2016.

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For example, this has been done successfully in Los Angeles County with the passage of Measure W, in Culver City with the passage of Measure CW, in the City of Los Angeles with the passage of Proposition O, and in the City of Santa Monica with the passage of Measure V.

U.S. EPA’s MS4 Permit Improvement Guide259 suggests the inclusion of a requirement to establish a citizen’s advisory group to participate in the development and implementation of the community’s stormwater program, explaining that “[b]y listening to the public’s concerns and coming up with solutions together, the permittee will gain the public’s support and the community will become invested in the program.” Furthermore, the U.S. EPA document Evaluation of the Role of Public Outreach and Stakeholder Engagement in Stormwater Funding Decisions in New England: Lessons from Communities260 describes benefits of engaging stakeholders in stormwater planning and funding that include, among other benefits: (1) providing a forum to share concerns and knowledge and (2) providing “[a]n opportunity to find the balance between costs and services that fee payers can support.” In Los Angeles County, this has been done on a regional basis through OurWaterLA, a diverse coalition of community leaders and organizations from across Los Angeles County, which was formed to support outreach to all residents in Los Angeles County about the importance of clean, safe, affordable and reliable water to the region’s communities. OurWaterLA works to make water issues accessible by developing informational materials, bringing new partners to the coalition, and hosting workshops and community events throughout Los Angeles County. The coalition strives to listen and help communities understand their power to make neighborhoods greener and healthier while enhancing the local economy and quality of life. OurWaterLA was a key supporter of the passage of Measure W by the voters, which established a dedicated revenue stream for stormwater projects to improve water quality and local water supply and provide other community benefits.

Citizen oversight committees have also been established to support implementation of some of the funding programs identified above, including Measure V and Proposition O. Coalitions and committees like these can be formed by Permittees to facilitate effective public participation in local and regional stormwater management programs.
b. Informational and Educational Activities (Part VIII.D.3.b of the Order).

The informational and educational activities requirements in previous permits for Ventura County, City of Long Beach, and Los Angeles County implemented federal requirements in 40 CFR sections 122.26(d)(2)(iv)(A) and (B)(6). This permit maintains the requirements from the previous permits, but allows for additional flexibility in how the Permittees may implement them. The Los Angeles Water Board recognizes that this flexibility will allow Permittees to focus resources and efforts on targeted pollutants and behaviors that are most problematic to individual communities or where efforts will result in the 259 U.S. EPA. 2010. MS4 Permit Improvement Guide. Apr. 2010. p. 22. 260 U.S. EPA. 2013. Evaluation of the Role of Public Outreach and Stakeholder Engagement in Stormwater Funding Decisions in New England: Lessons from Communities. EPA-100-K-13-0004. Office of Policy.

June 2013. p. 27.

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greatest improvements. These provisions support the broader federal requirements discussed earlier in this Fact Sheet.

For Part VIII.D.3.b of the Order, the Permittee has the flexibility of selecting activities and topics based on water quality priorities. Additionally, the Permittee may choose various methods for disseminating educational materials on pollution prevention or may promote pollution mitigation through public reporting of illicit discharges. In this way, the Permittee is expected to adapt the program efforts and resources to focus public education in targeted areas. This flexibility notwithstanding, the requirements implement federal regulations at 40 CFR sections 122.26(d)(2)(iv)(A) and 122.26(d)(2)(iv)(B)(6).

The U.S. EPA MS4 Permit Improvement Guide supports flexibility in PIPP programs through example fact sheet language:

The public education and outreach program must be tailored and targeted to specific water quality issues of concern in the relevant community. These community-wide and targeted issues must then guide the development of the comprehensive outreach program, including the creation of appropriate messages and educational materials. The permit includes a list of potential residential and commercial waste topics, but the permittee may also choose other issues that contribute significant pollutant loads to stormwater.
261
The U.S. EPA-issued permit for Boise Area MS4262 allows flexibility in that Permittees decide the effective methods and topics for prescribed target audiences. Similarly, the U.S. EPA-issued MS4 permit for the Rio Grande Watershed263 allows for Permittees to use a “tailored public education program using a mix of locally appropriate strategies, to target specific audiences and communities” and “[use] material or outreach programs directed toward targeted groups of commercial, industrial, and institutional entities likely to have significant storm water impacts.”
Resources for outreach methods and pollution prevention practices associated with Part VIII.D.3.b of the Order are available through U.S. EPA’s Non-point Source Toolbox available at https://cfpub.epa.gov/npstbx/.

5. Documentation, Tracking and Measurement of Effectiveness.

Part VIII.D.4 of the Order requires the Permittee to document and track selected activities and targets as well as report on the effectiveness of public information and participation activities. This enables the Los Angeles Water Board to ensure the program requirements are implemented. It also helps the Permittee to ascertain the most successful public participation efforts.

The previous 2010 Ventura County MS4 Permit required documentation of activities and strategies implemented and required effectiveness measurements on outreach to school children and the general public related to stormwater quality.

The previous 2014 City of Long Beach and 2012 Los Angeles County MS4 permits 261 U.S. EPA. 2010. MS4 Permit Improvement Guide. Apr. 2010. p. 20. 262 NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. pp. 30-32.
263 NPDES Permit No. NMR04A000 issued to Middle Rio Grande Watershed, effective December 22, 2014. p. 32.

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required documentation and effectiveness information to be reported in annual reports. The Regional MS4 Permit requires Permittees to document the selected activities, dates of activities, methods, targeted behavior, targeted pollutant, targeted audience, cultural outreach effort, and the metric chosen to measure effectiveness of the activity. This information must be made available upon request to the Los Angeles Water Board and reported in annual reports.264 The Regional Permit includes a new requirement for all Permittees to develop metrics and evaluate the success of the program, based on chosen metrics, in educating, raising awareness, and changing behaviors. U.S. EPA emphasizes permit conditions related to MCMs must be clear, specific, and measurable. 265 U.S.

EPA-issued permits266 include clear, specific, measurable requirements to document and track effectiveness of public information and outreach activities.

Additionally, several permit language examples in the Compendium of MS4 Permitting Approaches267 require Permittees to develop and/or use metrics to measure improved understanding of stormwater quality, support for the program, and pollutant management and disposal behaviors as defined by objectives in Part VIII.D.2 of the Order.

6. Annual Report Requirements.

Requirements to report PIPP activities in Attachment H (Annual Report Form) of the Order as well as effectiveness using metrics established in Part VIII.D.4 of the Order are based on federal requirements in 40 CFR 122.42(c)(1), (c)(2), and (c)(6) among others as identified in the Monitoring and Reporting Program (Attachment E). These reporting requirements ensure that Permittees evaluate the success of the program, in educating, raising awareness, and changing behaviors.

E. Industrial/Commercial Facilities Program

1. Background
Since the Nationwide Urban Runoff Program (NURP) study268 in the early 1980s, it has been demonstrated that sites of industrial activity have the potential to contribute higher quantities of pollutants in stormwater runoff when compared with other land uses. Data from the NURP study were analyzed further in the U.S.

Geological Survey (USGS) Urban Storm Water Data Base for 22 Metropolitan Areas Throughout the United States study.
269 The USGS report summarized
additional monitoring data compiled during the mid-1980s, covering 717 storm events at 99 sites in 22 metropolitan areas, and documented problems associated with metals and sediment concentrations in urban stormwater runoff. 264 40 CFR § 122.42(c)(4) requires “A summary of data, including monitoring data, that is accumulated throughout the reporting year;” 40 CFR § 122.42(c)(6) requires “A summary describing the number and nature of enforcement actions, inspections, and public education programs;” 265 Federal Register/ Vol. 79, No. 245/Monday, December 22, 2014/ Notices. P. 89320. 266 For example, see footnote , p. 14 and footnote , p. 45. 267 Compendium of MS4 Permitting Examples, Part 1: Six Minimum Control Measures. Office of Wastewater Management, Water Permits Division. November 2016. 810-U-16-001. 268 Results of the Nationwide Urban Runoff Program, Volume 1—Final Report. U.S. EPA. 1983. Office of Water. Washington, D.C.
269 U.S. Geological Survey Urban Storm Water Data Base for 22 Metropolitan Areas Throughout the United States. Driver, N.E., M.H. Mustard, R.B. Rhinesmith, and R.F. Middleburg. 1985. Report No. 85–337 USGS. Lakewood, CO.

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2. Legal Authority
The Permittee is ultimately responsible for discharges from its MS4. The Phase I regulations require, in part, that the applicant: (i) develop adequate legal authority, (ii) perform a source identification, and (iii) develop a management program to reduce the discharge of pollutants. (40 CFR section 122.26(d)(2).) The U.S. EPA MS4 Permit Improvement Guide states that, “Phase I MS4 regulations specify that several key elements be included in Phase I MS4 stormwater management programs [to control pollutants in stormwater discharges to the MS4 from industrial and commercial facilities]. These elements include:
adequate legal authority to require compliance and inspect sites, inspection of priority industrial and commercial facilities, establishing control measure requirements for facilities that may pose a threat to water quality, and enforcing stormwater requirements. In order to implement these requirements, MS4 permits require the development of an inventory of facilities and prioritization protocol and adequate staff training to ensure proper inspection and enforcement of requirements.”270
Federal regulations at 40 CFR section 122.26(d)(2)(ii) require MS4 operators to “[p]rovide an inventory, organized by watershed of the name and address, and a description (such as SIC codes) which best reflects the principal products or services provided by each facility which may discharge, to the municipal separate storm sewer, storm water associated with industrial activity.” Per 40 CFR section 122.26(d)(2)(iv)(C), with regards to industrial controls, the management plan shall include the following.
“A description of a program to monitor and control pollutants in storm water discharges to municipal systems from municipal landfills, hazardous waste treatment, disposal and recovery facilities, industrial facilities that are subject to section 313 of Title III of the Superfund Amendments and Reauthorization Act of 1986 (SARA),271 and industrial facilities that the municipal permit applicant determines are contributing a substantial pollutant loading to the municipal storm sewer system. The program shall:
(1) Identify priorities and procedures for inspections and establishing and implementing control measures for such discharges.
(2) Describe a monitoring program for storm water discharges associated with industrial facilities […]”
Per 40 CFR section 122.26(d)(2)(ii), as part of the Source Identification requirements, the municipality is required to “Provide an inventory, organized by watershed of the name and address, and a description (such as SIC codes) which best reflects the principal products or services provided by each facility which may discharge, to the municipal separate storm sewer, storm water associated with industrial activity.”
In the preamble to the 1990 regulations, U.S. EPA clearly states the intended strategy for discharges of stormwater associated with industrial activity:
270 U.S. EPA. MS4 Permit Improvement Guide (2010), Chapter 7, p. 85 (emphasis added). 271 See U.S. EPA’s Toxic Release Inventory (TRI) Program webpage at: https://www.epa.gov/toxicsrelease-inventory-tri-program

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“…Municipal operators of large and medium municipal separate storm sewer systems are responsible for obtaining system-wide or area permits for their system’s discharges. These permits are expected to require that controls be placed on storm water discharges associated with industrial activity which discharge through the municipal system.”
272
The U.S. EPA also notes in the preamble that “… municipalities will be required to meet the terms of their permits related to industrial dischargers.” 273
Similarly, in the U.S. EPA’s Guidance Manual (Chapter 3.0), U.S. EPA specifies that MS4 applicants must demonstrate that they possess adequate legal authority to:
a. Control construction site and other industrial discharges to MS4s; i. Prohibit illicit discharges and control spills and dumping; ii. Carry out inspection, surveillance, and monitoring procedures.

The document goes on to explain that "control," in this context means not only to require disclosure of information, but also to limit, discourage, or terminate a stormwater discharge to the MS4. Further, to satisfy its permit conditions, a Permittee may need to impose additional requirements on discharges from permitted industrial facilities, as well as discharges from industrial facilities and construction sites not required to obtain permits.

In the same Guidance Manual (Chapter 6.3.3), U.S. EPA states that the Permittee is ultimately responsible for discharges from their MS4. Consequently, the MS4 applicant must describe how the municipality will help the U.S. EPA and States authorized to implement the federal NPDES permit program to:
a. Identify priority industries discharging to their systems; i. Review and evaluate storm water pollution prevention plans (SWPPPs) and other procedures that industrial facilities must develop under general or individual permits;
ii. Establish and implement BMPs to reduce pollutants from these industrial facilities (or require industry to implement them); and iii. Inspect and monitor industrial facilities discharging storm water to the municipal systems to ensure these facilities are in compliance with their NPDES storm water permit, if required.

Therefore, Permittees are required to implement programs to control stormwater discharges associated with industrial activities and other commercial facilities identified as significant contributors of pollutants through the implementation of a mandatory baseline minimum set of source control BMPs; performance of an inspection program to verify the adequacy of BMP implementation in the field and compliance with municipal ordinances; and assist the Los Angeles Water Board in ensuring that industrial activities subject to regulations are covered by the State Water Board’s industrial stormwater general permit. Los Angeles Water Board will also assist the municipalities in case of instances of egregious non-compliance with the municipal ordinances and state and federal laws and regulations. 272 Federal Register, Vol. 55, No. 222, November 16, 1990, pp. 47990-48091. 273 Ibid.

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The provisions contained in the Order pertaining to the inspection and facility control program requirements for industrial and commercial facilities are also based on the requirements found in the previous permits. Those requirements, among others, were the subject of litigation between several permittees and the Los Angeles Water Board on the 2001 Los Angeles County MS4 permit (Order No. 01- 182). In that case, the Los Angeles County Superior Court upheld the inspection and facility control program requirements for industrial/commercial facilities and construction sites. The Court found that requiring permittees to inspect commercial and industrial facilities and construction sites is authorized under the Clean Water Act. The Court further determined that “[t]he Permit contains reasonable inspection requirements for these types of facilities. [Citation.] Additionally, permittees have the fee authority to impose a fee on the facility operator or owner to recover the cost of these inspections. As part of the scope of inspection, the Permit requires each permittee to confirm that operators are effectively implementing Best Management Practices (BMPs) in compliance with County and municipal ordinances, Regional Board Resolution 90-08 and the Stormwater Quality Management Plans (SQMPs). [Citation.] Addressing pollution after it has entered the storm sewer system is not working to meet legislative goals. More work is required at the source of pollution, and that is partially the basis on which this Court finds that the Permit’s inspection requirements are reasonable, and not onerous and burdensome.” (In re L.A. Cnty. Mun. Storm Water Permit Litig. (L.A. Super. Ct., No. BS 080548, Mar. 24, 2005), Statement of Decision from Phase II Trial on Petitions for Writ of Mandate, p. 17.)
There is currently pending litigation concerning the permittees’ fee authority to pay for inspections of industrial, commercial, and construction sites. In 2003, several Los Angeles County MS4 permittees filed test claims with the Commission on State Mandates alleging the requirements to conduct inspections at industrial facilities, commercial facilities, and construction sites in the 2001 permit (Order No. 01-182) were unfunded state mandates subject to reimbursement by the state pursuant to article XIII B, section 6 of the California Constitution. In 2009, the Commission determined that the provisions imposed state mandates as the provisions were not specifically found in federal law, but found that the requirements were not reimbursable because the permittees could charge fees to fund the inspection requirements. Both the Water Boards and the permittees appealed various aspects of the Commission’s decision. That litigation remains pending on several issues, including the permittees’ challenge regarding their fee authority issue. To date, no court has ruled specifically on this issue. (State of California Department of Finance, State Water Resources Control Board, and California Regional Water Quality Control Board, Los Angeles Region v. Commission on State Mandates; County of Los Angeles, et al., Real Parties in Interest (Super. Ct. Los Angeles County, Case No. BS130730, B292446, app. pending).

3. Industrial/Commercial Facilities Program Implementation The purpose of the Industrial/Commercial Facilities Pollutant Control Program is to ensure the implementation of adequate controls at all industrial and commercial sites in order to assist Permittees in achieving compliance with the water quality limitations for discharges from their MS4s. The applicable provisions in the Order are carried over from the prior MS4 permits. However, they have been slightly modified to better define the requirements. These provisions clarify the inventory requirements for all facilities that are critical sources of stormwater pollution, as

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well as requirements for industrial facilities (i.e. facilities listed in Part VIII.E.2.a.i) of the Order and commercial facilities (i.e. facilities listed in Parts VIII.E.2.a.ii through iv).

Part VIII.E.2.b of the Order lists the minimum necessary information required to develop and maintain an effective list of all facilities that are critical sources of stormwater pollution.

For ease of compliance and more clear guidelines, the requirements for industrial facilities (i.e., facilities that require enrollment in the Industrial General Permit) have been separated from the other facilities. Part VIII.E.3 of the Order sets provisions specific to commercial facilities listed in Parts VIII.E.2.a.ii through iv of the Order and Part VIII.E.4 of the Order sets forth provisions specific to industrial facilities.

While the requirements for all facilities include a business assistance program and facility inspections, the details of each component are tailored to the facility type.

The commercial facilities’ outreach and business assistance programs are tailored to raise awareness among commercial facility owners of their BMP requirements.

The industrial facilities’ business assistance program is tailored to raise awareness among industrial facility owners of the obligation to obtain and comply with permit requirements for their stormwater discharges. The inspection component for both commercial and industrial facilities is set forth to ensure effective implementation of BMPs to manage stormwater discharge from the facility. The Order also requires Permittees, during facility inspections, to confirm that industrial facilities are enrolled in the Industrial General Permit and have a current waste discharge identification (WDID) number. Inspection frequencies have been modified to start with more frequent inspections while giving the Permittee the opportunity to reduce the frequency for facilities that demonstrate compliance with the BMP requirements. This will give the Permittees the freedom to better utilize their resources by allocating them to areas of higher concern. Additionally, inspection frequencies for commercial facilities have been modified to require inspections of a facility every two years, ensuring that the first mandatory compliance inspection occurs no later than 2 years after the effective date of the Order. A minimum interval of 6 months between the compliance inspections is required. The scope of the inspections was clarified by listing possible BMPs that should be implemented at the facility to ensure that exposure of pollutants to stormwater is managed. The BMP categories are based on BMPs identified in the 2003 California Stormwater BMP Handbook, Industrial and Commercial as well as BMPs identified in Los Angeles Water Board Resolution No. 98-08.

Additionally, the provision for outreach is necessary to meet federal standards and federal requirements regarding stormwater management programs at 40 CFR section 122.26(d)(2)(iv), including subsections (A)(6) and (B)(6), which require educational outreach regarding pollutants in discharges of pesticides, herbicides, fertilizers, oil, and toxic materials.

Part VIII.E.6 of the Order sets requirements for a progressive enforcement procedure that outlines the minimum steps needed to enforce their municipalities’ stormwater requirements. In recognition of some of the Permittees’ concerns regarding the resource intensive efforts needed to elevate enforcement actions, a mechanism was provided through which Permittees can refer cases to the Los Angeles Water Board.

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Due to the level of technicality of industrial and commercial facilities inspections, Part VIII.A.3 of the Order sets requirements for staff training. These requirements are set to ensure pertinent staff possess the appropriate knowledge of the program.

F. Planning and Land Development Program

1. Legal Authority
The permit application requirements described in 40 CFR section 122.26(d) have formed the foundation for MS4 permits and remain applicable as elements in a stormwater management program. 40 CFR section 122.26(d)(2)(iv) requires, in part, that the large and medium MS4 applicant develop a management program.

Specifically, with regards to planning and land development and post-constructions controls, the management program shall include the following:
“(A) A description of structural and source control measures to reduce pollutants from runoff from commercial and residential areas that are discharged from the municipal storm sewer system that are to be implemented during the life of the permit, accompanied with an estimate of the expected reduction of pollutant loads and a proposed schedule for implementing such controls. At a minimum, the description shall include:
(1) A description of maintenance activities and a maintenance schedule for structural controls to reduce pollutants (including floatables) in discharges from municipal separate storm sewers;
(2) A description of planning procedures including a comprehensive master plan to develop, implement and enforce controls to reduce the discharge of pollutants from municipal separate storm sewers which receive discharges from areas of new development and significant redevelopment. Such plan shall address controls to reduce pollutants in discharges from municipal separate storm sewers after construction is completed.
(3) A description of practices for operating and maintaining public streets, roads and highways and procedures for reducing the impact on receiving waters of discharges from municipal storm sewer systems… (4) A description of procedures to assure that flood management projects assess the impacts on the water quality of receiving water bodies and that existing structural flood control devices have been evaluated to determine if retrofitting the device to provide additional pollutant removal from storm water is feasible.”

2. Background
Land development and urbanization have been linked to the impairment of aquatic life beneficial uses in numerous studies. Poorly planned and constructed new development and re-development projects have the potential to impact the hydrology of the watershed and the water quality of the surface waters.

Development without appropriate planning and controls often results in increased soil compaction, changes in vegetation and increased impervious surfaces. These conditions may lead to a reduction in groundwater recharge and changes in the flow regime of the surface water drainages. Historically, urban development has resulted in increased peak stream flows and flow duration, reduced base flows, and increased water temperatures. Pollutant loading in stormwater runoff often

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increases due to post-construction activities and because the stormwater runoff is directly connected to the storm drain system or to the surface water body, without the benefit of filtration through soil and vegetation.

The Planning and Land Development Program provisions in the 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 Permits require that Permittees impose requirements on development projects (including significant redevelopment projects) within their jurisdiction to address stormwater pollution and hydromodification impacts. These provisions establish:
▪ Water quality, flow reduction, and resources management criteria for applicable development projects within the Permittee’s jurisdiction. ▪ Hydromodification mitigation criteria for applicable development projects within the Permittee’s jurisdiction.
▪ Implementation requirements.

Except for some provisions that were updated and/or refined, the Order generally carries over the Planning and Land Development provisions included in the 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 Permits.

3. Implementation
a. Priority Development Projects
Part VIII.F.1 of the Order establishes the term “Priority Development Projects” for new development and redevelopment projects subject to water quality, flow reduction, and resources management criteria. Although the term Priority Development Project was not used in the 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 Permits, this change does not constitute a new requirement. The categories of development projects designated as Priority Development Projects are generally the same categories of new development and redevelopment projects that were subject to water quality, flow reduction, and resources management criteria in the previous permits. Part VIII.F.1.a.iv of the Order establishes that new development and redevelopment projects that create and/or replace 2,500 square feet or more of impervious area; discharge stormwater that is likely to impact a sensitive biological species or habitat; and are located in or directly to or are discharging directly to a “Sensitive Ecological Area” in Los Angeles County or an “Environmentally Sensitive Area” in Ventura County are Priority Development Projects. This is consistent with the 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 Permits.

Part VIII.F.1.c of the Order includes exemptions from Priority Development Project Structural BMP Performance Requirements through implementation of an approved Local Ordinance Equivalence or an approved Regional Stormwater Mitigation Program. These exemptions were included in the 2012 Los Angeles County MS4 Permit and 2014 City of Long Beach MS4 Permit. i. Hydromodification
Part VIII.F.2.a of the Order establishes hydromodification management requirements for Priority Development Projects within natural drainage systems for Los Angeles County Permittees and all development projects greater than 50 acres for Ventura County Permittees. This is the same

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as the applicability requirements in the 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 Permits. Under the 2012 Los Angeles County MS4 Permit, hydromodification requirements applied to all New Development and Redevelopment projects located in natural drainage systems. Under the 2010 Ventura County MS4 Permit, hydromodification requirements applied to all applicable New Development and Redevelopment projects identified in subpart 4.E.II of that permit (i.e., projects that would be referred to as Priority Development Projects under this Order), however hydromodificationspecific controls are only required for projects disturbing lands areas of fifty acres of greater.

The hydromodification management control criteria outlined in Part VIII.F.2.c of the Order carry over the criteria included in the 2010 Ventura County MS4 Permit, 2012 Los Angeles County MS4 Permit, and 2014 City of Long Beach MS4 Permit.
ii. Implementation Requirements
Part VIII.F.3 of the Order establishes implementation requirements related to project coordination; maintenance agreements and transfers; and tracking, inspection, and enforcement of post-construction BMPs.

These requirements are directly carried over from those included in the 2010 Ventura County MS4 Permit, 2012 Los Angeles County MS4 Permit, and 2014 City of Long Beach MS4 Permit.
b. Priority Development Project Structural BMP Performance Requirements
Part VIII.F.4 of the Order establishes requirements for Priority Development Projects for Permittees. Under these requirements, Permittees must require Priority Development Projects to retain a Stormwater Quality Design Volume (SWQDV). If retention of the SWQDV is infeasible or if there is an applicable groundwater replenishment opportunity, then Permittees may allow Priority Development Projects to use alternative compliance measures including:
onsite biofiltration or onsite flow-based BMPs in conjunction with offsite infiltration projects, groundwater replenishment projects, or offsite retrofit projects. These requirements are generally consistent with the corresponding requirements in the 2012 Los Angeles County, 2010 Ventura County, and 2014 City of Long Beach MS4 Permits.

Part VIII.F.4.c.i of the Order provides that on-site biofiltration may be used as an alternative compliance measure. Unlike the 2012 Los Angeles County, 2010 Ventura County, and 2014 City of Long Beach MS4 Permits, the Order does not directly include design specifications for biofiltration systems but instead references the design specifications in the County of Los Angeles Department of Public Works’ Low Impact Development Standards Manual and 2011 Ventura County Technical Guidance Manual. These specifications are generally consistent with the previous design specifications in Attachment H of the 2012 Los Angeles County MS4 Permit and 2011 Ventura County Technical Guidance Manual.

Part VIII.F.4.c.ii of the Order provides that on-site flow-based BMPs may be used as an alternative compliance measure for Permittees in situations where

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on-site biofiltration is not technically feasible. This option was not included in the 2012 Los Angeles County, 2010 Ventura County, and 2014 City of Long Beach MS4 Permits. This alternative compliance measure option is included in the Order to give an on-site treatment option for projects in areas where onsite biofiltration is technically infeasible. The requirements are similar to the mitigation criteria in Part VIII.F.4.d of the Order, however the BMP must be certified for “Enhanced Treatment” under the Washington State Department of Ecology’s TAPE Program; or an appropriate future BMP certification program developed by the State of California.

Part VIII.F.4.d of the Order establishes water quality mitigation criteria for projects in cases where the priority development project is utilizing offsite mitigation or an offsite ground water replenishment project to comply with its structural BMP performance requirements. This ensures that there is treatment of stormwater runoff from the project site. The Order updates the mitigation requirements included in the 2012 Los Angeles County, 2010 Ventura County, and 2014 City of Long Beach MS4 Permits.

G. Construction Program

1. Background
Soil disturbing activities during construction and demolition exacerbate sediment losses. Sediment is a primary pollutant impacting beneficial uses of watercourses.

Sediment also transports other pollutants such as nutrients, metals, and oils and greases. Sediments, and other construction activity pollutants must be properly controlled to reduce or eliminate adverse impacts.

Construction activities addressed by the Construction Program in the Order include the following:
• Any construction or demolition activity, including, but not limited to, clearing, grading, grubbing, or excavation, or any other activity. • Construction activity related to residential, commercial, or industrial development on lands currently used for agriculture including, but not limited to, the construction of buildings related to agriculture that are considered industrial pursuant to U.S. EPA regulations, such as dairy barns or food processing facilities.
• Construction activity associated with linear underground/overhead project (LUPs) including, but not limited to, those activities necessary for the installation of underground and overhead linear facilities (e.g., conduits, substructures, pipelines, towers, poles, cables, wires, connectors, switching, regulating and transforming equipment and associated ancillary facilities) and include, but are not limited to, underground utility mark-out, potholing, concrete and asphalt cutting and removal, trenching, excavation, boring and drilling, access road and pole/tower pad and cable/wire pull station, substation construction, substructure installation, construction of tower footings and/or foundations, pole and tower installations, pipeline installations, welding, concrete and/or pavement repair or replacement, and stockpile/borrow locations.
• Construction activities associated with oil and gas exploration, production, processing, or treatment operations or transmission facilities.

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• Activities resulting in storm water discharges from dredge spoil placement that occur outside of U.S. Army Corps of Engineers jurisdiction274 (upland sites) and that disturb one or more acres of land surface from construction activity.

Construction projects that intend to disturb one or more acres of land within the jurisdictional boundaries of a CWA section 404 permit should contact the appropriate Regional Water Board to determine whether this permit applies to the project.

2. Legal Authority
With respect to construction site stormwater runoff control, federal regulations set forth requirements that include implementation of BMPs, site inspection, enforcement, and educational and training measures for construction site operators.
40 CFR section 126.26(d)(2)(iv)(D) requires “A description of a program to implement and maintain structural and non-structural best management practices to reduce pollutants in storm water runoff from construction sites to the municipal storm sewer system…”
Per 40 CFR section 126.26(d)(2)(iv)(D)(2), the program must include “A description of requirements for nonstructural and structural best management practices.” Per 40 CFR section 126.26(d)(2)(iv)(D)(3), the program must include “A description of procedures for identifying priorities for inspecting sites and enforcing control measures…”
Per 40 CFR section 126.26(d)(2)(iv)(D)(4), the program must include “A description of appropriate educational and training measures for construction site operators.” 40 CFR section 122.34(b)(4) states that with respect to construction site stormwater runoff control for small MS4s, which is analogous to that for large MS4s:
“(i) [the permittee] must develop, implement, and enforce a program to reduce pollutants in any storm water runoff to your small MS4 from construction activities that result in a land disturbance of greater than or equal to one acre.

Reduction of storm water discharges from construction activity disturbing less than one acre must be included in your program if that construction activity is part of a larger common plan of development or sale that would disturb one acre or more. If the NPDES permitting authority waives requirements for storm water discharges associated with small construction activity in accordance with § 122.26(b)(15)(i), you are not required to develop, implement, and/or enforce a program to reduce pollutant discharges from such sites. (ii) Your program must include the development and implementation of, at a minimum:
(A) An ordinance or other regulatory mechanism to require erosion and sediment controls, as well as sanctions to ensure compliance, to the extent allowable under State, Tribal, or local law; (B) Requirements for construction site operators to implement appropriate erosion and sediment control best management practices; (C) Requirements for construction site operators to 274 A construction site that includes a dredge and/or fill discharge to any water of the United States (e.g., wetland, channel, pond, or marine water) requires a permit from the U.S. Army Corps of Engineers pursuant to CWA section 404 and a Water Quality Certification from the Regional Water Board or State Water Board pursuant to CWA section 401.

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control waste such as discarded building materials, concrete truck washout, chemicals, litter, and sanitary waste at the construction site that may cause adverse impacts to water quality; (D) Procedures for site plan review which incorporate consideration of potential water quality impacts; (E) Procedures for receipt and consideration of information submitted by the public, and (F) Procedures for site inspection and enforcement of control measures.” The inspection requirements for construction sites contained in the Order are also based on the requirements found in the previous permits. As previously noted, the inspection requirements contained in the 2001 Los Angeles County MS4 permit (Order No. 01-182) for construction sites were the subject of litigation between several permittees and the Los Angeles Water Board. As provided in more detail above, the Los Angeles County Superior Court upheld the inspection requirements for industrial/commercial facilities and construction sites in Order No. 01-182, finding that the “[t]he Permit contains reasonable inspection requirements for these types of facilities” and also that permittees have the authority to impose a fee on the facility operator or owner to recover the cost of these inspections. (In re L.A.

Cnty. Mun. Storm Water Permit Litig. (L.A. Super. Ct., No. BS 080548, Mar. 24, 2005), Statement of Decision from Phase II Trial on Petitions for Writ of Mandate, p. 17.) As previously noted above, there remains pending litigation on test claims filed by several Los Angeles County MS4 permittees concerning the permittees’ fee authority to pay for inspections of industrial, commercial, and construction sites.

The matter is currently at the Court of Appeal. To date, however, no court has ruled specifically on the fee authority issue. (State of California Department of Finance, State Water Resources Control Board, and California Regional Water Quality Control Board, Los Angeles Region v. Commission on State Mandates; County of Los Angeles, et al., Real Parties in Interest (Super. Ct. Los Angeles County, Case No. BS130730, B292446, app. pending).

3. Construction Program Implementation
The purpose of the Construction Program is to ensure the implementation of adequate controls at all construction sites in order to assist Permittees in achieving compliance with the receiving water limitation provisions and WQBELs applicable to discharges from their MS4s. The applicable provisions in the Order are carried over from existing MS4 Permits. However, they have been slightly modified to better define the requirements.

For ease of compliance and more clear guidelines, the requirements for construction sites that disturb one acre or greater of land (or construction sites less than one acre that are part of a common plan of development totaling one acre or greater) have been separated from construction sites that disturb less than one acre and are not part of a common plan of development. Part VIII.G.4 of the Order sets provisions specific to sites that disturb less than one acre of land while Part VIII.G.5 of the Order sets provisions specific to sites that disturb one acre or greater of land or sites less than one acre that are part of a common plan of development totaling one acre or greater.

Part VIII.G.4.a of the Order states that Permittees shall require the implementation of effective BMPs at construction sites disturbing less than one acre. To better assist Permittees, this part includes a list of applicable BMPs. To ensure effective implementation of these BMPs, Part VIII.G.4.b of the Order requires Permittees to inspect these sites.

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Part VIII.G.5.a.i of the Order states that Permittees shall verify enrollment in the Construction General Permit prior to issuing a grading or building permit. Also, Permittees shall require operators of these sites to prepare and submit a postconstruction plan for the Permittee’s review and approval. These post-construction requirements are based on some of the provisions listed in Part VIII.F of the Order.

These provisions are not listed in the Construction General Permit.

Part VIII.G.5.b of the Order lists the minimum necessary information required to develop and maintain an effective list of all construction sites one acre or greater.

Part VIII.G.5.c of the Order requires inspection of these sites to verify enrollment in the Construction General Permit, implementation of appropriate BMPs, or implementation of proper post-construction BMPs. The requirement for Permittees to develop standard operation procedures for their inspection procedures has been removed since inspection requirements are streamlined as part of the inspection requirements of the Order. Similarly, the requirement for Permittees to require an Erosion and Sediment Control Plan (ESCP) has been removed since an ESCP include the elements of a Storm Water Pollution Prevention Plan (SWPPP).

Therefore, these requirements shall be satisfied via SWPPPs.

Part VIII.G.6 of the Order requires that Permittees implement their Progressive Enforcement Policy set forth in Part VIII.B as it pertains to ensuring that construction site operators come into compliance with all stormwater requirements.

Due to the technical nature of construction activities and BMP implementation, Part VIII.A.3 of the Order sets requirements for staff training. These requirements are set to ensure pertinent staff possess the appropriate knowledge of the program.

H. Public Agency Activities Program

1. Federal Requirements
The Los Angeles Water Board has incorporated the Public Agency Activities Program into the Order per the following federal requirements:

Clean Water Act section 402(p)(3)(B)(ii) and (iii) require that “[p]ermits for discharges from municipal storm sewers … shall include a requirement to effectively prohibit non-stormwater discharges into the storm sewers; and shall require controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants.” 40 CFR section 122.26(d)(2)(iv)(A) requires that the stormwater management program is based on, among other items, “[a] description of structural and source control measures to reduce pollutants from runoff from commercial and residential areas that are discharged from the municipal storm sewer system that are to be implemented during the life of the permit, accompanied with an estimate of the expected reduction of pollutant loads and a proposed schedule for implementing such controls.” This section goes on to identify component areas to address structural and source control measures. The components related to the Public Agency Activities Program include 40 CFR sections 122.26(d)(2)(iv)(A)(1), (3), (4), and (6), and are described below.
40 CFR section 122.26(d)(2)(iv)(A)(1) states that the stormwater management program must include “[a] description of maintenance activities and a

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maintenance schedule for structural controls to reduce pollutants (including floatables) in discharges from municipal separate storm sewers;” 40 CFR section 122.26(d)(2)(iv)(A)(3) states that the stormwater management program must include “[a] description of practices for operating and maintaining public streets, roads and highways and procedures for reducing the impact on receiving waters of discharges from municipal storm sewer systems, including pollutants discharged as a result of deicing activities;” 40 CFR section 122.26(d)(2)(iv)(A)(4) states that the stormwater management program must include “[a] description of procedures to assure that flood management projects assess the impacts on the water quality of receiving water bodies and that existing structural flood control devices have been evaluated to determine if retrofitting the device to provide additional pollutant removal from storm water is feasible;” and
40 CFR section 122.26(d)(2)(iv)(A)(6) states that the stormwater management program must include “[a] description of a program to reduce to the maximum extent practicable, pollutants in discharges from municipal separate storm sewers associated with the application of pesticides, herbicides and fertilizer which will include, as appropriate, controls such as educational activities, permits, certifications and other measures for commercial applicators and distributors, and controls for application in public right-of-ways and at municipal facilities.”
40 CFR section 122.41(n) describes conditions under which an upset of treatment may constitute an affirmative defense to an action brought for noncompliance. At 40 CFR section 122.41(n)(1) “[u]pset means an exceptional incident in which there is unintentional and temporary noncompliance with technology-based permit effluent limitations because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.” The regulation further provides for conditions of affirmative defense and requirements to demonstrate an upset at 40 CFR sections 122.41(n)(2) and (3): Within the Regional MS4 Permit, the provisions for Emergency Procedures in Part VIII.H.10. of the Order allow for an affirmative defense subject to the conditions of 40 CFR 122.41(n)(1), (2), and (3).
40 CFR section 122.42(c) requires the owner or operator of an MS4 to submit an annual report that includes in part “(1) The status of implementing the components of the storm water management program that are established as permit conditions; (2) Proposed changes to the storm water management programs that are established as permit condition. Such proposed changes shall be consistent with §122.26(d)(2)(iii) of this part; (3) Revisions, if necessary, to the assessment of controls and the fiscal analysis reported in the permit application under §122.26(d)(2)(iv) and (d)(2)(v) of this part; (4) A summary of data, including monitoring data, that is accumulated throughout the reporting year…” and “(6) A summary describing the number and nature of enforcement actions, inspections, and public education programs…”

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2. General Provisions
Permittees previously covered under the 2012 Los Angeles County MS4 Permit, the 2014 City of Long Beach MS4 Permit, and the 2010 Ventura County MS4 Permit must continue existing programs while updating those programs, as necessary, to comply with the requirements of the Order. The Order consolidates requirements among the three previous permits, updates requirements to reflect completed program elements, and provides additional flexibility for BMP implementation. The most notable changes from previous permits are discussed below.

3. Public Agency Facility and Activity Management
The requirements for BMP implementation address federal requirements in 40 CFR sections 122.26(d)(2)(iv)(A)(1), (3), and (6). In addition, 40 CFR section 122.44(k) authorizes BMP requirements in permits for stormwater subject to Clean Water Act section 402(p). The BMP requirements in this section are similar to those in other permits, including the U.S. EPA-issued permit for Washington, D.C., which requires proper operation and maintenance, inspections, and proper disposal of residual water from treatment control BMPs.
275 Several examples in U.S. EPA’s
Compendium of MS4 Permitting Approaches require BMP implementation for municipal activities, often through development of a SWPPP. 276
Part VIII.H.3 of the Order requires each Permittee implement BMPs (identified in the inventory in Part VIII.H.2 of the Order), which may be structural and/or nonstructural. For implemented BMPs, the Permittee must inspect, maintain, properly operate, and properly dispose of any residual water produced by a treatment control BMP.
277 Municipal operations are often performed by contractors; therefore, the Order requires contractual requirements to ensure BMPs are properly implemented.

The previous 2010 Ventura County MS4 Permit prescribed specific BMPs, referenced to the Caltrans Storm Water Quality Handbook Maintenance Staff Guide or as approved by the Executive Officer.278 The Order allows the Permittee to determine appropriate BMPs corresponding to activities. In doing so, Permittees have flexibility to incorporate advanced techniques beyond those in the references.

Nonetheless, the Los Angeles Water Board encourages Permittees to consult Caltrans Storm Water Quality Handbook Maintenance Staff Guide as guidance for selecting BMPs.

The Order removes requirements specific to flood management projects in the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 permits because MCMs related to flood management projects and flood control procedures 275 NPDES Permit No. DC0000221 issued to the Government of the District of Columbia, as modified November 9, 2012, pp. 16-17).
276 Compendium of MS4 Permitting Examples, Part 1: Six Minimum Control Measures. Office of Wastewater Management, Water Permits Division. November 2016. 810-U-16-001. pp. 38-45. 277 See Attachment A (Definitions). Residual Water means “In the context of the Order, water remaining in a structural BMP subsequent to the drawdown or drainage period. The residual water typically contains high concentration(s) of pollutants.” Treatment Control BMP means “Any engineered system designed to remove pollutants by simple gravity settling of particulate pollutants, filtration, biological uptake, media absorption or any other physical, biological, or chemical process.” 278 Appendix B of the Caltrans Storm Water Quality Handbook Maintenance Staff Guide, May 2003, and its addenda.

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are now included in the inventory required by revised Part VIII.H.2 of the Order and, as such, the Permittee is required to assign appropriate BMPs, considering impacts of flood management projects on the water quality of the receiving water bodies. Flood control management is largely outside the scope of the MS4 permit; therefore, additional BMP requirements are not retained from previous Orders.

The Order removes numeric limitations for residual water produced by treatment control BMPs that were included in previous permits for Los Angeles County, City of Long Beach, and Ventura County. The Order includes treatment control BMPs in the requirements for Public Agency Facility and Activity Management. The numeric limitations are unnecessary as there is no longer an option in the Order to discharge residual water from treatment BMPs to the MS4. Their removal streamlines the permit requirements and improves clarity.

4. Vehicle and Equipment Washing; Landscape, Park, and Recreational Facilities Management; Storm Drain Operation and Maintenance; Road Reconstruction, Streets and Road Pollutant Management, and Parking Facilities.

The specific BMPs in Parts VIII.H.4 through 9 of the Order are based on section 402(p)(3)(B) of the CWA, which mandates that a permit for discharges from MS4s must effectively prohibit the discharge of non-stormwater to the MS4; require controls to reduce pollutants in discharges from the MS4 to the maximum extent practicable (MEP) including BMPs control techniques, and system, design and engineering methods; and such other provisions as the State deems appropriate for the control of pollutants. The specific BMPs for Parts VIII.H.4 through 9 of the Order are commonly accepted practices that the Los Angeles Water Board considers necessary to control pollutants discharged to the MS4 to the maximum extent practicable. Vehicle wash water is a prohibited non-stormwater discharge; thus, requirements in Part VIII.H.4 of the Order are also necessary to comply with the prohibition. U.S. EPA included BMP requirements similar to those in Part VIII.H.5 of the Order (Landscape, Park, and Recreational Facilities Management) in MS4 permits for Washington, D.C.,
279 and Boise Area,280 and Middle Rio Grande
Watershed.
281 Similarly, U.S. EPA provides example requirements to label catch basins in the MS4 Improvement Guide. Street sweeping reduces debris and pollutants that may become entrained in stormwater and urban runoff. Additionally, street sweeping may reduce clogging of catch basins and extend the life of infiltration BMPs.
282
The Permittee must implement specific BMPs for vehicle and equipment washing; landscape, park, and recreational facilities management; storm drain operation and maintenance; catch basin cleaning; road reconstruction; streets and road pollutant 279 NPDES permit (DC0000221) issued to Government of the District of Columbia, with final signed Modification #1, effective November 9, 2012. pp. 16-17. 280 NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. p. 25.
281 NPDES Permit No. NMR04A000 issued to Middle Rio Grande Watershed, effective December 22, 2014. p. 29.
282 Urban Drainage and Flood Control District, 2010. Urban Storm Drainage Criteria Manual, Volume 3.

Chapter 5, Fact Sheet S-11, available at https://udfcd.org/wpcontent/uploads/uploads/vol3%20criteria%20manual/01_USDCM%20Volume%203.pdf. Last accessed June 20, 2018.

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management; and parking facilities maintenance. The Order’s requirements in these areas have been updated from the previous permits to be consistent with the Trash Amendments283 and to remove catch basin prioritization requirements already completed by the Permittees.

This Part of the Order does not require Permittees to quantify trash removed from catch basins, as was required in the 2010 Ventura County MS4 Permit, rather, the Order aligns trash requirements with the Statewide Trash Amendments. Trash requirements are included in Part III.B of the Order.

Previous permits for Los Angeles County, City of Long Beach, and Ventura County permits required that the public agency program address infiltration to sanitary sewers and related preventative maintenance. For the Order, these requirements are addressed as illicit connections and discharges in Part VIII.I of the Order to more closely align with federal requirements. Provisions for controls on infiltration to sanitary sewers and related preventative maintenance address federal requirements in 40 CFR section 122.26(d)(2)(iv)(B)(7) as a component of the IDDE program.

Parking areas were not specifically identified for additional BMPs in the previous Ventura County permit. The remaining BMP requirements under these Parts are retained from previous permits for Los Angeles County, City of Long Beach, and Ventura County, with a specification for parking areas with a sediment/gravel base.

To provide a phased approach for parking area requirements to Ventura County Permittees, an applicability threshold for parking areas greater than 1 acre or any parking lot used for heavy vehicle storage was added.

5. Emergency Procedures
The provisions in Part VIII.H.10 of the Order are consistent with federal regulations in 40 CFR section 122.41(n) as described earlier in this Fact Sheet. Permittees are required to conduct repairs of essential public service systems and infrastructure in emergency situations. In these situations, a Permittee is allowed a self-waiver from implementing facility and activity specific BMPs identified in Part VIII.H.3 of the Order, as well as BMPs described in Part VIII.H.4 through 9 of the Order. An emergency includes only those situations included as conditions necessary for demonstration of an upset at 40 CFR section 122.41(n). For each claimed emergency, the Permittee shall submit to the Los Angeles Water Board a statement of the occurrence of the emergency, an explanation of the circumstances, and the measures that were implemented to reduce the threat to water quality, no later than required by applicable federal NPDES regulations.

6. Other Changes to Program Requirements
The Order discontinues cross references to other regulatory requirements that were provided in previous permits for Los Angeles County and the City of Long Beach. This change reduces unnecessary language, as it is naturally implied that Permittees are not exempt from other regulatory requirements within the Order (e.g., Development Construction, Planning and Land Development requirements) 283 Amendment to the Water Quality Control Plan for Ocean Waters of California (Ocean Plan) to Control Trash and Part 1 Trash Provisions of the Water Quality Control Plan for Inland Surface Waters, Enclosed Bays, and Estuaries of California (ISWEBE Plan). Final Resolution No. 2015-0019. The OAL approved the Trash Amendments on December 2, 2015. The U.S. EPA approved the Trash Amendments on January 12, 2016.

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or general permit requirements (e.g., General Permit for Storm Water Discharges Associated with Construction and Land Disturbance Activities [NPDES No.

CAS000002] and/or the General Permit for Storm Water Discharges Associated with Industrial Activities [NPDES No. CAS000001]), if applicable).

The Order does not require the Public Agency Program to include an Inventory of Existing Development for Retrofitting Opportunities, as was required in the 2012 Los Angeles County and the 2014 City of Long Beach MS4 permits. The previous permit provisions addressed federal requirements in 40 CFR section 122.26(d)(2)(iv)(A)(4). This requirement has been completed by Los Angeles County and City of Long Beach Permittees and a similar requirement is included under the Planning and Land Development Program in the Order. The previous 2010 Ventura County MS4 Permit also contained a similar requirement related to identifying eligible public and private off-site mitigation project sites in the Planning and Land Development program.
284

7. Documentation and Tracking
Federal regulations in 40 CFR section 122.44(k)(4) require the Permitting Authority to establish requirements for BMPs where “The practices are reasonably necessary to achieve effluent limitations and standards or to carry out the purpose and intent of the CWA.” The regulation contains a footnoted reference to the Guidance Manual for Developing Best Management Practices (BMPs), 285 for
additional technical information on BMPs and the elements of BMPs. As described in the Manual, recordkeeping involves collecting background information that is pertinent to the BMP plan or the BMP itself. California Water Code section 13383 authorizes the Los Angeles Water Board to establish monitoring, inspection, entry, reporting, and recordkeeping requirements. The Order requires documentation and tracking as a form of recordkeeping that is integral to BMP implementation. Without documentation and tracking, the Permittee cannot effectively ensure proper BMP implementation that is protective of water quality. U.S. EPA-issued MS4 permits such as the one issued to the District of Colombia,
286 routinely require
documentation and tracking interconnected with clear, specific, measurable requirements.

The Permittee must document and track the Public Agency Activities Program through the inventory developed in Part VIII.H.2 of the Order. This inventory is a framework for setting up periodic facility assessments and for developing, where necessary, facility stormwater pollution prevention plans. Documenting and tracking of BMPs through the inventory help to ensure that public agency facilities are monitored and receiving water quality is protected.

Part VIII.H.2 of the Order addresses, in part, federal requirements in 40 CFR section 122.26(d)(2)(iv)(A)(1), (3), and (6). A public agency oversees numerous facilities and performs many activities and must therefore identify activities that may 284 Waste Discharge Requirements for Storm Water (Wet Weather) and Non-storm Water (Dry Weather) Discharges from the Municipal Separate Storm Sewer Systems Within the Ventura County Watershed Protection District, County of Ventura and the Incorporated Cities Therein. Order 09-0057, NPDES No.

CAS004002. Issued May 7, 2009, Corrected January 13, 2010. 285 U.S. EPA, 1993. Guidance Manual for Developing Best Management Practices (BMPs). Office of Water.

EPA No. 833/B-93-004. October 1993.
286 NPDES permit (DC0000221) issued to Government of the District of Columbia, effective June 22, 2018. pp. 19-22.

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result in discharges of pollutants to the MS4. As follows, the requirements in 40 CFR sections 122.26(d)(2)(iv)(A)(1), (3), and (6) effectively require such an inventory. The MS4 Permit Improvement Guide recommends an inventory that is similar to the requirements in the Order.287
Permittees must develop and maintain an inventory of public facilities that are potential sources of pollutants to the MS4. Permittees formerly covered under the 2012 Los Angeles County and 2014 City of Long Beach MS4 permits may use information from the Public Facilities Inventory developed under the previous permit to comply with this provision, provided that all requirements in Part VIII.H.2 of the Order are met. The previous 2010 Ventura County MS4 Permit did not require an inventory but required BMP implementation for specific activities and specific types of facilities as well as BMP documentation. Thus, the previous 2010 Ventura County MS4 Permit requirements are effectively similar to the Order’s inventory requirement. Under the Order, activities with potential to discharge pollutants to the MS4 must be included in the inventory and must be associated with facilities where the activity occurs. The list of facility types to include in the inventory is retained from previous permits for Los Angeles County and the City of Long Beach and correspond to similar requirements in the 2010 Ventura County MS4 Permit; however, streets and roads; catch basins; and stormwater capture, control, and treatment devices are added to the inventory list. The Order consolidates information requirements from the three previous permits. The framework of this requirement is slightly different than the three previous permits, but results in equivalent requirements to implement BMPs.

The previous permit for the City of Long Beach required the Permittee to update the inventory twice during the permit term; whereas, the Regional MS4 Permit requires the inventory to be updated once per permit term. The Los Angeles Water Board believes that this change will allow for reduced burden, without diminishing the overall integrity of the inventory.

8. Annual Report Requirements
The reporting requirements for the Public Agency Activities Program in Attachment H (Annual Report Form) of the Order are based on federal requirements in 40 CFR 122.42(c) (1), (2), (3), (4) and (6) among others as identified in the Monitoring and Reporting Program (Attachment E) and are necessary to ensure program requirements are implemented.

I. Illicit Discharge Detection and Elimination Program
The title of this section has changed from Illicit Connections and Illicit Discharges Elimination Program in previous permits to Illicit Discharge Detection and Elimination (IDDE) Program. The change has been made to match federal regulation language.

1. Federal Requirements
The Los Angeles Water Board has incorporated the Illicit Discharge Detection and Elimination Program into the Regional MS4 Permit per the following federal requirements:
287 U.S. EPA. 2010. MS4 Permit Improvement Guide. April 2010. pp. 67-69.

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Clean Water Act section 402(p)(3)(B)(ii) requires that “[p]ermits for discharges from municipal storm sewers shall include a requirement to effectively prohibit nonstormwater discharges into the storm sewers;…” Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B) require that the stormwater management program shall be based on “a description of a program, including a schedule, to detect and remove (or require the discharger to the municipal storm sewer to obtain a separate NPDES permit for) illicit discharges and improper disposal into the storm sewer.” The proposed management program shall include “[a] description of a program, including inspections, to implement and enforce an ordinance, orders or similar means to prevent illicit discharges to the municipal storm sewer system,” per subsection (1) of the above federal regulation.

Federal regulations at 40 CFR section 122.26(b)(2) define “illicit discharge” as “any discharge to a municipal separate storm sewer that is not composed entirely of storm water except discharges pursuant to a NPDES permit (other than the NPDES permit for discharges from the municipal separate storm sewer) and discharges resulting from firefighting activities.” Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(1) state that the following non-stormwater discharges may be allowed if they are not determined to be a significant source of pollutants to the MS4: water line flushing, landscape irrigation, diverted stream flows, rising ground waters, uncontaminated ground water infiltration, uncontaminated pumped ground water, discharges from drinking water supplier distribution systems, foundation drains, air conditioning condensation, irrigation water, springs, water from crawl space pumps, footing drains, lawn watering, individual residential car washing, flows from riparian habitats and wetlands, dechlorinated swimming pool discharges, and street wash water. If, however, these discharges are determined to be a significant source of pollution then they must be prohibited.

Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(1) through (7) provide the IDDE program requirements including a “description of a program, including inspections, to implement and enforce an ordinance, orders or similar means to prevent illicit discharges to the municipal separate storm sewer system,” field screening, investigation procedures, spill prevention, public reporting, educational activities, and a description of controls to limit infiltration of seepage from municipal sanitary sewers.

2. General Provisions
Part VIII.I.1 of the Order implements federal requirements in Clean Water Act section 402(p)(3)(B)(ii) and 40 CFR section 122.26(d)(2)(iv)(B)(3). The Permittee must continue to implement their IDDE program, maintain it in written form, and update it, as necessary. The requirements in the IDDE program are retained from previous permits for Los Angeles County, City of Long Beach, and Ventura County and have been reworded for improved clarity. Many of the program components are monitoring and reporting efforts. As such, some requirements are included in the MRP for non-stormwater outfall-based screening and monitoring.

The Regional MS4 Permit considers the procedures in the MRP for the nonstormwater outfall-based screening and monitoring program as part of the IDDE program. These Regional MS4 Permit requirements address federal regulations at 40 CFR 122.26(d)(2)(iv)(B)(2), (5), and (6), which are program requirements for the IDDE that state the permittee must include in the IDDE program: “(2) [a] description of procedures to conduct on-going field screening activities during the life of the

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permit, including areas or locations that will be evaluated by such field screens;” “(5) [a] description of a program to promote, publicize, and facilitate public reporting of the presence of illicit discharges or water quality impacts associated with discharges from municipal separate storm sewers” and “(6) [a] description of educational activities, public information activities, and other appropriate activities to facilitate the proper management and disposal of used oil and toxic materials.”

3. Illicit Discharge Detection and Elimination
Clean Water Act section 402(p)(3)(B)(ii) requires MS4 permits to “effectively prohibit non-stormwater discharges into the storm sewers.” Parts VIII.I.2 and 3 of the Order implement the federal requirement, in part, by requiring the development of procedures to investigate and eliminate illicit discharges. In addition to the broad federal requirement, the Regional MS4 Permit requires a timeline of 72 hours to initiate the investigation. This timeline is retained from previous permits for Los Angeles County and the City of Long Beach but is slightly different from the previous 2010 Ventura County MS4 Permit requirement of “one business day.” Nonetheless, the Los Angeles Water Board believes “72 hours” is a clearer requirement. U.S. EPA encourages permit writers to include clear, specific, measurable requirements in permits as is evident through the Phase II remand rule288 and guidance documents.289
The previous Los Angeles and City of Long Beach permits include a requirement to notify upstream jurisdictions when an illicit discharge has been determined to have originated upstream of their jurisdictional boundary. Communication with upstream jurisdictions is essential to eliminating illicit discharges as the upstream entity might not be aware of the discharge leaving their MS4.

The Regional MS4 Permit retains the requirement that if a Permittee is unable to eliminate an ongoing illicit discharge, or other circumstances prevent the full elimination of an ongoing illicit discharge, the Permittee shall require diversion of the entire flow to the sanitary sewer or treatment. In the event of either above circumstance, the Permittee shall notify the Los Angeles Water Board in writing within 30 days, providing a written plan for review and comment. The goal of this requirement is to provide a permanent solution for ongoing illicit discharges. This requirement was not included in the previous 2010 Ventura County MS4 Permit but it is necessary as it supports the federal requirement to effectively prohibit nonstormwater discharges through the MS4.

The illicit connection requirements as stated in the previous 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 permits, have been combined with illicit discharge requirements in Part VIII.I of the Order.

Combining illicit discharges and illicit connections into one section streamlines the Regional MS4 Permit while still meeting the NPDES requirements stated in 40 CFR section 122.26 (d)(1)(v)(B). Illicit connections are often treated as illicit discharges, 288 U.S. EPA. 2016. National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System General Permit Remand Rule, 81 Federal Register, p 89326. 289 U.S. EPA. 2010. MS4 Permit Improvement Guide. April 2010. p.5.

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as is evident in U.S. EPA-issued permits for Boise Area290 and District of Columbia.
291
The illicit connection screening requirements included in the three previous permits are discontinued in the Regional MS4 Permit. They have been removed to eliminate redundancy and streamline the permit. As illicit connections are a source of illicit discharges by performing illicit discharge screening and investigations the Permittee is fulfilling that requirement. If the Permittee eliminates the sources of illicit discharges, then they will eliminate illicit connections.

4. Infiltration from Sanitary Sewer to MS4 – Preventative Maintenance The NPDES requirements of 40 CFR section 122.26(d)(2)(vi)(B)(7) require that the IDDE program include “A description of controls to limit infiltration of seepage from municipal sanitary sewers to municipal separate storm sewer systems where necessary.” The Sanitary Sewer Preventative Maintenance requirements were in the Public Agency Activity Program in the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 permits but were not any section of the previous 2010 Ventura County MS4 Permit. Proper sanitary sewer preventative maintenance decreases the probability that a sanitary sewer line will back up, overflow, or leak, causing potential contact with the MS4 or directly to the receiving water. By moving these requirements into the IDDE section, the Regional Permit implements the above-mentioned requirements of 40 CFR 122.26(d)(2)(iv)(B)(7).

5. Spill Response
Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(4) require a “description of procedures to prevent, contain, and respond to spills that may discharge into the municipal separate storm sewer.” Spills, leaks, sanitary sewer overflows, and illicit dumping or discharges can introduce a range of pollutants into the storm system.

A quick response to a spill can prevent the pollutant from reaching the MS4 or the receiving water. Often, a different entity might be responsible for spill response in a community (e.g., fire department); therefore, it is imperative that adequate communication exists between stormwater and spill response staff to ensure that spills are documented and investigated in a timely manner.

The language in the Regional MS4 Permit has been streamlined to maintain the federal requirements but allow for flexibility for each Permittee to design their program to best fit the needs of their community. Other U.S. EPA-issued permits, such as the one issued to the District of Columbia,
292 include a similar streamlined
approach to spill response that states “the permittee shall continue to implement procedures to prevent, contain, and respond to spills that may discharge into the MS4. The permittee shall provide for the training of appropriate personnel in spill 290 NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. p. 27 and 32.
291 NPDES permit (DC0000221) issued to Government of the District of Columbia, with final signed Modification #1, effective November 9, 2012. pp. 35-36. 292 NPDES permit (DC0000221) issued to Government of the District of Columbia, with final signed Modification #1, effective November 9, 2012. p. 25

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prevention and response procedures.” Additionally, the U.S. EPA-issued permit for Boise Area293 also includes similar spill response requirements.294

6. Public Reporting of Non-Stormwater Discharges and Spills Federal regulations at 40 CFR section 122.26(d)(2)(iv)(B)(5) require the permittee to develop a description of a program “to promote, publicize, and facilitate public reporting of the presence of illicit discharges or water quality impacts associated with discharges from municipal separate storm sewer.” The Permittee(s) needs to promote the program to help in the identification and termination of illicit discharges. The Regional MS4 Permit establishes requirements for the Permittees, individually or as a group, to develop public education campaigns and public reporting of illicit discharges.

The language used in this Regional MS4 Permit has been streamlined to allow for adaptation of new technology other than telephone hotlines, such as websites, cellular telephone applications, and social media. Permittees must provide the public with at least one way of reporting illicit discharges, spills, and observed water quality impacts associated with the MS4.

7. Documentation and Tracking
The Regional MS4 Permit retains the overall documentation and tracking requirements in Part VIII.I.8 of the Order from the 2012 Los Angeles County and 2014 City of Long Beach MS4 permits. These requirements are more specific than in the previous 2010 Ventura County MS4 Permit but are necessary to ensure that Permittees are effectively prohibiting non-stormwater discharges, as required by Clean Water Act section 402(p)(3)(B)(ii). Additionally, the EPA MS4 Permit Improvement Guide295 provides an example requirement to “track all investigations to document at a minimum the date(s) the illicit discharge was observed; the results of the investigation; any follow-up of the investigation; and the date the investigation was closed.” Other U.S. EPA issued permits, such as for the Boise Area,
296 include similar approaches to IDDE, which require the Permittee to maintain a record documenting all complaints or reports of illicit discharges and responses take by the Permittee.

While the documentation requirements are less specific in some ways than those in the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 permits, the requirements in the Regional MS4 Permit still meet the requirements of federal regulations. Specific documentation requirements are covered by Annual Reporting Requirements in the Regional MS4 Permit. The removal of specific requirements allows for flexibility, removes redundancy, and improves alignment 293 NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. p. 29.
294 For example, a Permittee could follow the Cal OES: California Hazardous Materials Spill/Release Notification Guidance when reporting and addressing spills. The Booklet is a guidance document that summarizes emergency notification requirements including when to notify, who to notify, how to notify and what to include in the notification. (Anderson, Trevor et al. Cal OES Governor’s Office of Emergency Services. California Hazardous Materials Spill/Release Notification Guidance. February 2014.) 295 U.S. EPA. 2010. MS4 Permit Improvement Guide. April 2010. p. 33. 296 NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. p. 24 - 25.

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among the three permits by allowing the Permittees to adjust their program to be the most effective within their community while still meeting the federal requirement.

The Permittee must track all suspected sources of non-stormwater discharges, starting with sources suspected of being sanitary sewage. To streamline tracking requirements within the Regional MS4 Permit, tracking requirements have been added to Part VIII.I.8 of the Order. To meet the documentation and tracking requirements, the Permittees may use the outfall database inventory developed per the MRP, which contains information on non-stormwater discharge characterization at outfalls. Documenting and tracking of illicit discharges through the inventory help to ensure that all illicit discharges are investigated and addressed, and water quality is protected.

8. Annual Report Requirements
The reporting requirements in Attachment H (Annual Report Form) are based on federal requirements in 40 CFR section 122.42(c)(1), (4) and (6) and others as identified in the Monitoring and Reporting Program (Attachment E) and are necessary to ensure program requirements are implemented.

X. RATIONALE FOR WATERSHED MANAGEMENT PROGRAMS
The Watershed Management Program is a voluntary alternative compliance pathway that allows Permittees to implement permit requirements in an integrated manner on a watershed basis, including demonstrating compliance with numeric WQBELs by implementing BMPs.

A. Previous Permit Requirements
Watershed Management Program provisions were carried over from the 2012 Los Angeles County and the 2014 City of Long Beach MS4 permits to the Regional MS4 Permit. Furthermore, the Regional MS4 Permit incorporates requirements and recommendations in the State Board Order WQ 2020-0038. However, one notable change from these two permits is the elimination of the option to develop either a Watershed Management Program (WMP) or an Enhanced Watershed Management Program (EWMP). In the previous permits, Permittees developing WMPs and EWMPs were largely subject to the same requirements except in two respects: 1) Permittees developing a WMP were not required to maximize opportunities to capture the 85th percentile, 24-hour storm event but were required to conduct a Reasonable Assurance Analysis (RAA) for every waterbody-pollutant combination in the WMP, and 2) Permittees developing an EWMP were required to maximize opportunities to capture the 85th percentile, 24-hour storm event by implementing regional multi-benefit stormwater projects but were not required to conduct a RAA except in drainage areas where retention to the 85th percentile, 24-hour storm event was not feasible. The previous permits allowed Permittees to either develop a WMP or EWMP with the expectation that only Permittees that had geotechnical issues with capturing the runoff from the 85th percentile, 24-hour storm event would opt for a WMP. However, Permittees implementing both WMPs and EWMPs sought opportunities to capture the runoff from the 85th percentile, 24-hour storm events and Permittees implementing both WMPs and EWMPs faced geotechnical issues related to capturing the runoff from the 85th percentile, 24-hour storm event throughout the area covered by the WMP or EWMP.

Therefore, in practice, there was little distinction between the WMPs and EWMPs. For this reason, the Regional MS4 Permit eliminates the distinction made between a WMP

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and EWMP so that these programs are now all termed Watershed Management Programs.

The 2010 Ventura County MS4 Permit did not include WMPs as an alternative compliance pathway. Rather, the prior permit only included the separate compliance pathways for receiving water limitations in the receiving water limitation provisions and water quality based effluent limitations based on TMDL WLAs in the TMDL provisions.

It did not provide the opportunity to comply with permit provisions in a watershed-based integrated manner through WMPs. Ventura County Permittees proposed inclusion of the Watershed Management Program for their next permit in their ROWD, stating that “[t]he Program supports the inclusion of a watershed management approach within the next Ventura County MS4 Permit, similar to the Watershed Management Programs (WMP) outlined in Part VI.C of the 2012 Los Angeles County NPDES Permit (LA Permit).”
297 Therefore, this proposed approach was included for Ventura County Permittees in the Regional MS4 Permit.

B. General Rationale for All Watershed Management Programs The WMPs are a voluntary alternative compliance pathway by which Permittees can meet the requirements in the Order, and are developed on a watershed or subwatershed basis. The purpose of the WMPs is to provide a framework for Permittees to implement the requirements of the Order in an integrated and collaborative fashion to address water quality priorities on a watershed scale, including complying with the requirements of Part V (Receiving Water Limitations), Part IV.B (Total Maximum Daily Load Provisions) and Attachments K through S, by customizing the control measures in Parts III.B (Prohibitions – Non-Stormwater Discharges) and Part VIII (Minimum Control Measures) of the Order. This watershed management paradigm is consistent with federal regulations that support the development of permit conditions, as well as the implementation of stormwater management programs, at a watershed scale (40 CFR §§ 122.26(a)(3)(ii), 122.26(a)(3)(v), and 122.26(d)(2)(iv)). U.S. EPA has issued a Watershed-Based NPDES Permitting Policy Statement (U.S. EPA, 2003) that defines watershed-based permitting as an approach that produces NPDES permits that are issued to point sources on a geographic or watershed basis. In this policy statement, U.S. EPA explains that, “[t]he utility of this tool relies heavily on a detailed, integrated, and inclusive watershed planning process.” U.S. EPA identifies a number of important benefits of watershed permitting, including more environmentally effective results; the ability to emphasize measuring the effectiveness of targeted actions on improvements in water quality; reduced cost of improving the quality of the nation’s waters; and more effective implementation of watershed plans, including TMDLs, among others.

Furthermore, the California Watershed Improvement Act of 2009 authorizes MS4 permittees statewide to develop and implement voluntary watershed improvement plans.298 State Water Board Order WQ 2015-0075, which upheld the 2012 Los Angeles County MS4 Permit with some modifications, clarifies that “[t]he California Watershed Improvement Act of 2009 grants authority to local government permittees regulated by an MS4 permit to develop and implement watershed improvement plans, but does not limit the authority of a regional water board to impose terms related to watershed management in an MS4 permit. Further, the terms of the Watershed Management Programs are largely consistent with the watershed improvement plans authorized by 297 Ventura Countywide Stormwater Quality Management Program. Report of Waste Discharge. January 2015.
298 Wat. Code, §§ 16100 to 16104.

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the Act, so a permittee can comply with the Regional Permit while also using the authority provided by the California Watershed Improvement Act of 2009 if it so chooses.”299
Additionally, Public Law 115-436 Water Infrastructure Improvement Act approved on January 14, 2019 established section 402(s) of the Clean Water Act authorizing integrated plans that address both municipal wastewater and stormwater management as a potential compliance path that may be incorporated into an NPDES permit.

Integrated planning is designed to help municipalities identify efficiencies in implementing requirements that arise from distinct permitting programs, particularly how best to make capital investments (Integrated Municipal Stormwater and Wastewater Planning Approach Framework, EPA, June 5, 2012). Under this law, an integrated plan can be used to implement any requirements relating to “a combined sewer overflow,” “a capacity, management, operation, and maintenance program for sanitary sewer collection systems,” “a municipal stormwater discharge,” “a municipal wastewater discharge,” and a “water quality-based effluent limitation to implement an applicable wasteload allocation in a total maximum daily load.” The integrated plan can include “a schedule of compliance, under which actions taken to meet any applicable water qualitybased effluent limitation may be implemented” and “the implementation of projects, including innovative projects, to reclaim, recycle, or reuse water; and green infrastructure.” (33 USCA § 1342(s).) The integrated planning approach does not relax or change regulatory permitting standards, but rather recognizes existing flexibilities in the Clean Water Act to sequence and schedule compliance projects that may be relevant to multiple permitting programs. (Id. at subd. (s)(5).) While the watershed management programs authorized in the Order are not “integrated plans” as defined in section 402(s) of the Clean Water Act, these watershed level plans share many of the same underlying principles and advance the same goals that prompted the Los Angeles Water Board to adopt a watershed-based permitting approach for the Order. While all municipalities are encouraged to consider integrated planning approaches for their stormwater and wastewater management, municipalities participating in watershed management programs are particularly encouraged to use their watershed management programs as part of a larger integrated planning process where appropriate and useful.

Furthermore, SB 485 updated state law to expressly authorize the Sanitation Districts of Los Angeles County (LACSD) to use their facilities and expertise to help member agencies to meet MS4 permit requirements to specifically “divert, manage, treat, and discharge stormwater and dry weather runoff, as well as make beneficial use of the water.” (Health & Safety Code § 4730.68) Passage of this law with further facilitate innovative, watershed level approaches to stormwater management that are consistent with the watershed-based permitting approach in the Order.

The watershed-based permitting approach is supported by a number of state and nationwide studies regarding MS4 pollution (Little Hoover Commission, Clearer Structure, Cleaner Water: Improving Performance and Outcomes at the State Water Boards (January 22, 2009). In 2008, the National Research Council published a report stating: “The course of action most likely to check and reverse degradation of the nation’s aquatic resources would be to base all storm water and other wastewater discharge permits on watershed boundaries instead of political boundaries.” (National Research Council, Urban Stormwater Management in the U.S. (October 15, 2008) 299 State Water Board Order WQ 2015-0075, p. 8, footnote 30 (2015 AR, p. SB-AR-013203).

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(emphasis in original).) The report acknowledged the challenges of such an approach would include “the inevitable limits of an urban municipality’s authority within a larger watershed”, but said the approach would be “essential” even though it would likely take years to implement.

As noted in subpart A above, the prior permits for Los Angeles County and the City of Long Beach included provisions related to the development and implementation of Watershed Management Programs as an alternative compliance pathway. However, the prior Ventura County Permit did not. The Order allows all Permittees, including those in Ventura County, to participate in WMPs as an alternative compliance pathway. There are many reasons supporting this approach, as set forth below.

First, a watershed-based structure for permit implementation is consistent with TMDLs for waterbodies in both Los Angeles and Ventura counties developed by the Los Angeles Water Board and U.S. EPA, which are established at a watershed or subwatershed scale. The majority of Los Angeles County Permittees have already been implementing approved Watershed Management Programs. Furthermore, Ventura County Permittees have already been collaborating on a watershed scale to develop and implement monitoring and implementation plans required by TMDLs.

Second, an emphasis on a watershed-based approach is appropriate and necessary at this stage in the region’s MS4 program to shift the focus of the Permittees from rote program development and implementation to more targeted, water quality driven planning and implementation. Addressing MS4 discharges on a watershed scale focuses on water quality results by emphasizing the receiving waters within the watershed. The conditions of the receiving waters drive management actions, which in turn focus on the measures to address pollutant contributions from MS4 discharges.

The ultimate goal of the Watershed Management Programs is to ensure that MS4 discharges: (i) achieve applicable WQBELs that implement TMDLs, (ii) do not cause or contribute to exceedances of receiving water limitations, and (iii) for non-stormwater discharges from the MS4, are not a source of pollutants to receiving waters.

Third, after 30 years of program implementation, it is critical that the Permittees design and implement their permit requirements based on their improved knowledge of stormwater and urban runoff and its impacts on local receiving waters and by employing BMPs and other control measures that have been developed and refined over the past three decades. The Watershed Management Programs are driven by strategic planning and implementation, which will ultimately result in more cost-effective implementation.

The Watershed Management Programs will provide permittees with the flexibility to prioritize and customize control measures to address the water quality issues specific to the watershed or subwatershed, consistent with federal regulations (40 CFR § 122.26(d)(2)(iv)).

Importantly, a focus on watershed implementation does not mean that the Permittees must expend funds unrelated to their MS4 discharges. Rather, the Permittees within each watershed are expected to collaborate to develop a watershed strategy to address the high priority water quality problems within each watershed. They have the option of implementing the strategy in the manner they find to be most effective at achieving the necessary water quality outcomes. Each Permittee can implement the strategy individually within its jurisdiction, or the Permittees can group together to implement the strategy throughout the watershed.

While the Order includes a new compliance pathway for addressing MS4 discharges on a watershed basis for Ventura County Permittees, the Order includes recognition of the

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importance of continued program implementation on jurisdictional levels. The Order also acknowledges that jurisdictional and watershed efforts may be integrated to achieve water quality outcomes.

In the Order, the watershed management program provisions serve as the mechanism for this program integration. Since jurisdictional activities also serve watershed purposes, such activities can be integrated into the Permittees’ Watershed Management Programs. Such opportunities for program integration inherently provide flexibility to the Permittees in implementing their programs. Program integration can be expanded or minimized as the Permittees see fit. Some Permittees may opt to continue jurisdictionspecific implementation for certain programs, while for other program areas more collaborative watershed scale implementation may be more effective. Permittees identify individual roles and responsibilities as part of the Watershed Management Program.

Permittees can customize the BMPs to be implemented, or required to be implemented, for new and re-development, construction, and existing development areas. Flexibility to determine which industrial or commercial sites are to be inspected is also provided to the Permittees. Educational approaches are also to be determined by the Permittees under the Order. Significant leeway is also provided to the Permittees in using methods to assess the effectiveness of their various runoff management programs. This flexibility is further extended to the monitoring program requirements, which allow the Permittees to develop monitoring approaches to several aspects of the monitoring program.

The challenge in drafting the Order was to provide the flexibility described above, while ensuring that the Order provides baseline requirements and is still enforceable. To achieve this, the Order prescribes baseline or default requirements, such as receiving water limitations, discharge prohibitions, TMDL provisions, and minimum control measures, while providing the Permittees with flexibility to propose customized actions as part of their watershed management program.

C. Schedule for Development or Revision of the Watershed Management Program Timelines to submit a Watershed Management Program to the Los Angeles Water Board for approval are indicated in Part IX of the Order. To encourage community and stakeholder involvement in the development of the Watershed Management Programs, the Order requires that the draft Watershed Management Programs are made available for public review prior to approval by the Los Angeles Water Board or Executive Officer on behalf of the Los Angeles Water Board.

The deadlines for Ventura County Permittees to develop the WMP(s) considered various factors such as: the small number of Ventura County Permittees compared to Los Angeles County Permittees (12 compared to 87); the well-established collaboration among Ventura County Permittees through their Ventura Countywide Stormwater Quality Management Program; the significantly fewer applicable TMDLs (16 compared to 35); and their decade long experience implementing watershed based TMDL implementation plans to achieve the 2010 Ventura County MS4 Permit TMDL provisions including WQBELs. Therefore, the timeframe to submit the draft plan(s) is adequate and consistent with the WMP timeframe provided in the previous 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit.

The deadlines for Los Angeles County Permittees to submit a revised RAA and revised WMP were included in the Los Angeles 2012 MS4 Permit. These deadlines were established in State Water Board Order WQ 2015-0075. The State Board Order also

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specified a date of June 30, 2021 for Los Angeles County Permittees under the 2012 Los Angeles County MS4 Permit to submit a revised RAA and revised WMP to the Los Angeles Water Board. Although the State Water Board Order did not amend the 2014 City of Long Beach MS4 Permit, the City of Long Beach was also subject to this deadline due to its participation in three WMPs under the 2012 Los Angeles County MS4 Permit (Lower Los Angeles River WMP, Lower San Gabriel River WMP, Los Cerritos Channel WMP). However, the Nearshore Watersheds WMP, which was developed pursuant to the 2014 City of Long Beach MS4 Permit, was not subject to the deadline in the State Water Board Order WQ 2015-0075. Nevertheless, the Order requires all Los Angeles County MS4 Permittees to update their WMPs to conform to the requirements of the Regional MS4 Permit Order (e.g. address new or revised TMDL deadlines) within 3 months of receipt of comments from the Los Angeles Water Board that revisions are necessary, or as otherwise directed by the Executive Officer.

D. Participation in Watershed Management Programs

1. Ventura County Permittees
Ventura County Permittees that elect to develop a Watershed Management Program or join and existing Watershed Management Program must submit a Notice of Intent (NOI) to the Los Angeles Water Board. During the development of the WMP, Ventura County Permittees are deemed in compliance with the receiving water limitations pursuant to Part V of the Order for the waterbody pollutant combinations that are identified in the NOI provided they continue to implement their existing stormwater management programs and comply with all other parts of the Order (e.g. discharge prohibitions, standard provisions, minimum control measures) as discussed in Part IX.F.4 of the Order.

Ventura County Permittees may request an extension of the deadlines for submission of the NOI, submission of a draft plan, and submission of a final plan.

The extension is subject to approval by the Los Angeles Water Board or the Executive Officer. Ventura County Permittees that are granted an extension for any deadlines for development of the Watershed Management Program shall be subject to the baseline requirements in Part VIII of the Order and shall demonstrate compliance with all receiving water limitations pursuant to Part V of the Order until Ventura County Permittees have an approved Watershed Management Program in place. Likewise, Ventura County Permittees that do not opt to develop a Watershed Management Program are subject to the baseline stormwater management program requirements in the Order and must demonstrate compliance with applicable WQBELs and receiving water limitations through monitoring data collected from the Permittee’s outfall(s) and/or receiving waters as described in Part VII of the Order.

2. Los Angeles County Permittees
Los Angeles County Permittees that were on baseline requirements of the 2012 Los Angeles County MS4 Permit may choose to join an existing Watershed Management Program but may not develop a new individual Watershed Management Program. The City of Long Beach under the 2014 City of Long Beach MS4 Permit can choose to join another existing Watershed Management Program.

Los Angeles County Permittees that participated in a Watershed Management Program approved under the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit are presumed to be participating in the Watershed Management Program in this Order unless the Permittee notifies the Los Angeles

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Water Board of its intent to discontinue its participation. Los Angeles County Permittees that do not elect to continue participation in a Watershed Management Program are subject to the baseline stormwater management program requirements in the Order and must demonstrate compliance with applicable WQBELs and receiving water limitations through monitoring data collected from the Permittee’s outfall(s) and/or receiving waters as described in Part VII of the Order.

Los Angeles County Permittees that opt to continue implementing an approved Watershed Management Program were required to revise their RAA and submit a revised Watershed Management Program per the timelines indicated in the 2012 Los Angeles County MS4 Permit. No changes to this requirement have been proposed consistent with deadlines established pursuant to State Water Board Order WQ 2015-0075 and WQ 2020-0038. Until a revised Watershed Management Program is approved by the Los Angeles Water Board, Los Angeles County Permittees are required to continue implementing their existing Watershed Management Program. Also note that any WMP development related provisions added by the aforementioned State Water Board 2015 WQ Order to the 2012 Los Angeles County MS4 Permit, including a section in the Watershed Management Program provisions titled “Watershed Management Program Resubmittal Process” is now integrated in Part IX of the Regional MS4 Permit Order as applicable and appropriate in context of the Regional MS4 Permit.

E. Program Development
The goal of a Watershed Management Program is to facilitate cooperative implementation of strategies, control measures, and BMPs among Permittees and, potentially, other partners within a watershed or subwatershed to control discharges of pollutants from the MS4 to levels that achieve WQBELs and do not cause or contribute to exceedances of receiving water limitations, and which are also implement the MEP standard for stormwater discharges and the requirement to effectively prohibit nonstorm discharges through the MS4 to receiving waters. Each Watershed Management Program must:
• Prioritize water quality issues resulting from stormwater and non-stormwater discharges through the MS4 to receiving waters within each Watershed Management Area,
• Identify and implement strategies, control measures, and BMPs to achieve applicable water quality-based effluent limitations and/or receiving water limitations, consistent with applicable compliance schedules in the Order, • Execute an integrated monitoring and assessment program to determine progress towards achieving applicable limitations, and
• Modify strategies, control measures, and BMPs as necessary based on analysis of monitoring data collected pursuant to the MRP to ensure that applicable water quality-based effluent limitations and receiving water limitations and other milestones set forth in the Watershed Management Program will be achieved.

Watershed Management Programs must be developed using the Los Angeles Water Board’s Watershed Management Areas (see Attachments B and C of the Order). Where appropriate, Watershed Management Areas may be separated into subwatersheds to focus water quality prioritization and implementation efforts by receiving water.

Furthermore, Permittees have the flexibility to format their WMP as appropriate (e.g.,

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Ventura County Permittees can submit one WMP with subchapters for each watershed; a group of Los Angeles County Permittees can submit one WMP that includes portions of two adjacent watersheds; Ventura and Los Angeles County Permittees can submit one WMP for a watershed that straddles the two counties).

Permittees must identify the water quality priorities within each Watershed Management Area that will be addressed by the Watershed Management Program consistent with 40 CFR section 122.26(d)(2)(iv) and Part IX of the Order. At a minimum, these priorities must include achieving some or all applicable water quality-based effluent limitations and/or receiving water limitations established pursuant to TMDLs and included in the Order.

The Watershed Management Program must include an evaluation of existing water quality conditions, including characterization of stormwater and non-stormwater discharges from the MS4 and receiving water quality, consistent with 40 CFR §§ 122.26(d)(1)(iv) and 122.26(d)(2)(iii), to support identification and prioritization/ sequencing of management actions.

On the basis of the evaluation of existing water quality conditions, water body-pollutant combinations must be classified into one of the three categories listed in in Part IX.B.3 of the Order. If a Watershed Management Program does not identify a particular water body-pollutant combination, compliance with that water body-pollutant combination will not be covered under the Watershed Management Program and the Permittees have to demonstrate compliance with the baseline requirements (i.e., applicable receiving water limitations pursuant to Part V of the Order and with applicable interim and final water quality-based effluent limitations in Part IV and Attachments K-S of the Order for that water body-pollutant combination through monitoring collected from the Permittee’s outfall(s) and/or receiving waters as described in Part VII of the Order).

Consistent with 40 CFR sections 122.26(d)(1)(iii) and 122.26(d)(2)(ii), Permittees must utilize existing information to identify known and suspected stormwater and nonstormwater pollutant sources in discharges to the MS4 and from the MS4 to receiving waters and any other stressors related to the highest water quality priorities (Categories 1 and 2). Based on the findings of the source assessment, the issues within each watershed must be prioritized and sequenced per the provisions in the Order.

Permittees must identify strategies, control measures, and BMPs to implement through their jurisdictional stormwater management programs, or collectively on a watershed scale, with the goal of creating an efficient program to focus individual and collective resources on watershed priorities, particularly achieving WQBELs and receiving water limitations addressed by the Watershed Management Program. The following provisions of the Order may be part of the watershed control measures within a Watershed Management Program:
• Minimum Control Measures. Permittees may assess the minimum control measures (MCMs) as defined in the Order to identify opportunities for focusing resources on the high priority issues in each watershed. For each of the 6 minimum control measures identified in the Order, Permittees may propose modifications that will achieve equivalent pollutant control given watershed priorities. • Non-Stormwater Discharge Measures. Where Permittees identify non-stormwater discharges from the MS4 as a source of pollutants in the source assessment, the Watershed Control Measures must include strategies, control measures, and/or BMPs that will be implemented to effectively eliminate the source of pollutants.

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These may include measures to prohibit the non-stormwater discharge to the MS4, additional BMPs to reduce pollutants in the non-stormwater discharge or conveyed by the non-stormwater discharge, or strategies to require the non-stormwater discharge to be separately regulated under a general NPDES permit. Note that the BMPs to comply with Part III.A (Prohibitions – Non-Stormwater Discharges) of the Order are customizable but the requirement to prohibit non-stormwater from being a source of pollutants is not customizable.
• TMDL Control Measures. Permittees must compile control measures that have been identified in TMDLs and corresponding implementation plans. If not sufficiently identified in previous documents, or if implementation plans have not yet been developed (e.g., EPA established TMDLs), the Permittees must evaluate and identify control measures to achieve water quality based effluent limitations and/or receiving water limitations established in the Order pursuant to these TMDLs.

As part of the Watershed Management Program, Permittees must conduct a Reasonable Assurance Analysis (RAA) that consists of an assessment (through quantitative analysis or modeling) to demonstrate that the activities and control measures (i.e., BMPs) identified in the Watershed Control Measures will achieve applicable water quality based effluent limitations and/or receiving water limitations with compliance deadlines during the permit term. The objective of the RAA shall be to demonstrate the ability of Watershed Management Programs to ensure that Permittees’ MS4 discharges achieve applicable water quality-based effluent limitations and do not cause or contribute to exceedances of receiving water limitations.

Permittees must incorporate and, where necessary develop, interim requirements and compliance schedules into the plan consistent with 40 CFR section 122.47(a). Interim requirements and schedules shall be used to measure progress towards addressing the highest water quality priorities and achieving applicable water quality-based effluent limitations and/or receiving water limitations. Where the TMDL provisions do not include interim or final water quality based effluent limitations and/or receiving water limitations with compliance deadlines during the permit term, Permittees must identify interim requirements and compliance schedules to ensure significant progress toward achieving interim and final water quality based effluent limitations and/or receiving water limitations with deadlines beyond the permit term (40 CFR § 122.47(a)(3)).

Schedules must be developed for both the strategies, control measures and BMPs to be implemented by each individual Permittee within its jurisdiction and for those that will be implemented by multiple Permittees on a watershed scale. Schedules must be adequate for measuring progress throughout the permit term and incorporate deadlines as specified in Part IX.B.9 of the Order.

Where compliance schedules are not available (e.g., final TMDL deadlines), Permittees may request a Time Schedule Order as discussed in Part XI.E of this Fact Sheet.

Permittees may propose a schedule in the Watershed Management Program that is longer than the compliance schedule set forth by the TMDL if a TSO has been approved by the Los Angeles Water Board for a waterbody pollutant combination in that TMDL.

F. Watershed Management Program Implementation
Each Permittee must implement the Watershed Management Program immediately after determination by the Los Angeles Water Board that the Watershed Management Program meets the requirements of the Order and is approved.

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Permittees may request an extension of deadlines for achievement of interim milestones and final compliance deadlines established pursuant to Part IX.C.3 of the Order, only with the exception of those final compliance deadlines established in a TMDL program of implementation adopted through the state’s basin plan amendment process.

Permittees shall provide requests in writing sufficiently in advance of the deadline to allow the Los Angeles Water Board to evaluate the request and shall include in the request the justification for the extension. Extensions must be affirmatively approved by the Los Angeles Water Board.

G. Integrated Watershed Monitoring and Assessment
Clean Water Act section 402(a)(2) among other statutory and regulatory provisions as identified in the MRP (Attachment E) requires the permitting authority to prescribe conditions for MS4 permits to ensure compliance, including conditions on data and information collection, reporting, and such other requirements as appropriate.

Consistent with this requirement, Permittees in each Watershed Management Area must develop an integrated monitoring program to assess the progress toward achieving the water quality based effluent limitations and/or receiving water limitations per the compliance schedules, and the progress toward addressing the highest water quality priorities for each Watershed Management Area. The integrated watershed monitoring and assessment program shall contain the basic elements (receiving water monitoring, stormwater outfall monitoring, non-stormwater outfall monitoring), and achieve the objectives of, the Monitoring and Reporting Program (MRP) (Attachment E of the Order).

Note that unlike the WMP which is voluntary, the development of an integrated monitoring program pursuant to the MRP is a requirement for all Permittees regardless of participation in a WMP. Therefore, participants in an integrated monitoring program do not have to match the participants in a Watershed Management Program. For example, if a Permittee indicates in their WMP NOI that they are leaving a Watershed Management Program, this does not automatically apply to the corresponding integrated monitoring program. The Permittee shall continue to be part of the existing integrated monitoring program unless the Permittee specifically provides the Los Angeles Water Board written notification. In such a case, Part III.D.1.d of the MRP applies.

H. Adaptive Management Process
Permittees in each Watershed Management Program must implement an adaptive management process, which is a periodic, comprehensive program evaluation, including re-analysis of data and/or modeling, and modification process to determine progress toward achieving WQBELs and receiving water limitations and to adapt the Watershed Management Program to become more effective at achieving WQBELs and receiving water limitations. Permittees shall submit the results in conjunction with their ROWD. In implementing the adaptive management process, Permittees shall consider the elements specified in Part IX.E of the Order. Note that in the 2012 Los Angeles County Permit and the 2014 City of Long Beach MS4 Permit, the adaptive management process was required to be implemented every 2 years and the results were submitted in conjunction with the Annual Report and the ROWD. Many Permittees in their ROWDs requested to decrease the adaptive management results submittal frequency. This is a reasonable request because requiring Permittees to implement the adaptive management process every 2 years is unnecessary given the multi-year nature of many projects and programs where the design, construction, and implementation often span

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more than 2 years. Furthermore, Permittees are already reporting their progress on an annual basis through their Annual Reports and may propose modifications to their Watershed Management Programs at any point in response to this annual evaluation.

Therefore, the Order requires Permittees to submit adaptive management results in conjunction with the ROWD (180 days prior to the Order expiration date) with the expectation that Permittees are implementing their adaptive management process throughout the implementation of their Watershed Management Program when necessary.

Permittees are required to report on the adaptive management process results per Part IX.E.4 of the Order. Based on the results of the adaptive management process, Permittees may propose any modifications necessary to improve the effectiveness of the Watershed Management Program as a separate submittal to the Los Angeles Water Board as necessary. Permittees must implement any modifications to the Watershed Management Program upon approval by the Los Angeles Water Board.

XI. RATIONALE FOR COMPLIANCE DETERMINATION PROVISIONS
The Order adds Part X, Compliance Determination for WQBELs and receiving water limitations. In the previous permits, there was no single compliance determination section.

Rather, the previous permits included individual compliance determination provisions within many different sections and Permittees were required to read them all together to determine how their compliance would be determined.
300 For better organization and for ease of
determining compliance, the Order consolidates many of these provisions where appropriate, particularly those related to WQBELs and receiving water limitations, into one section to reduce redundancies and improve clarity.

Provisions specifying that compliance with the Watershed Management Program provisions in Part IX of the Order may constitute compliance with the receiving water limitation provisions in Part V of the Order were previously included in the 2012 Los Angeles County Permit and the 2014 Long Beach Permit. They were not previously included in the 2010 Ventura County Permit. In the Order, the Los Angeles Water Board continues to offer multiple paths to compliance with receiving water limitations. The number of TMDLs, and myriad water quality issues that the TMDLs address, is unprecedented anywhere else in California.

The Los Angeles Water Board worked closely with U.S. EPA in implementing the requirements of the 1999 consent decree between U.S. EPA and several environmental groups when developing these TMDLs. As shown in Table F-24, the TMDLs implemented in the Order cover every coastal watershed in the Los Angeles Region. Most of these TMDLs were initially incorporated in the prior MS4 permits (Order No. R4-2010-0108, Order No. R4- 2012-0175, and Order No. R4-2014-0024). The extensive and enforceable TMDL implementation programs, coupled with Permittee commitments to implement watershed solutions to address all impairments in regional waters, allowed this Board to incorporate alternative compliance mechanisms contingent upon implementation of approved Watershed Management Programs. This unique compliance mechanism provided an incentive and robust framework for Permittees in the 2012 Los Angeles County MS4 Permit and the 2014 Long Beach MS4 Permit to craft comprehensive pathways to achieve compliance with receiving water limitations – both those addressed by TMDLs and those not addressed by TMDLs. In the Order, the Los Angeles Water Board extends this approach to Ventura County Permittees that choose to take advantage of this compliance alternative. 300 For example, the 2012 Los Angeles County Permit included compliance related provisions in the following sections among others: interim and final WQBELs, Watershed Management Programs, Time Schedule Orders, and Monitoring and Reporting Program Requirements.

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The Compliance Determination provisions in Part X of the Order are organized as follows.

The first section addresses some general provisions related to compliance determination.

The second section addresses WQBELs and receiving water limitations for pollutants other than trash. The third section addresses a WQBELs and receiving water limitations for trash.

The fourth section addresses commingled discharges. The last section addresses Time Schedule Orders. Each of these sections are discussed in turn below.

A. General Compliance Provisions
Consistent with State precedent, compliance with water quality standards is and remains the ultimate goal of the Order.301 To that end, the Order requires compliance with WQBELs and receiving water limitations. Pursuant to section 13360 of the Water Code, the Water Board may not dictate the manner of compliance. Permittees may comply with the WQBELs and receiving water limitations in the Order in any lawful manner. Part X.A.1 of the Order describes where compliance will be determined for these limitations. Part X.A.2 of the Order restates longstanding precedent that the socalled “iterative process” (as Part V.C of the Order is often referred to as) does not constitute compliance with receiving water limitations in Part V.A and V.B of the Order.

This issue is discussed in greater detail in Part VII of this Fact Sheet.

B. WQBELs and Receiving Water Limitations for Pollutants Other Than Trash As described in Parts V.B (WQBELs), VI (Rationale for TMDL Provisions), and VII (Rationale for Receiving Water Limitations) of this Fact Sheet, the Order incorporates WQBELs and receiving water limitations to ensure MS4 discharges do not cause or contribute to exceedances of water quality standards.

1. Compliance Paths
The Los Angeles Water Board is in a unique position to be able to offer multiple paths to compliance with WQBELs and receiving water limitations in the Order. Alternative compliance options, however, differ depending on whether the limitation is considered an “interim limitation” or “final limitation”.

For waterbody pollutant combinations addressed by TMDL, the compliance path is as follows. The Order includes requirements in Part IV to implement WLAs assigned to MS4 discharges from 45 TMDLs. The TMDL provisions in Part IV.B and Attachments K-S of the Order include WQBELs and/or receiving water limitations based on the applicable WLAs. TMDLs adopted through the State’s basin planning process are required to include programs of implementation pursuant to California Water Code section 13242, including implementation schedules, for attaining water quality standards. TMDLs adopted by U.S. EPA do not include implementation schedules; however, in some instances the Los Angeles Water Board has adopted an implementation schedule through the State’s basin planning process (see Part VI.F of this Fact Sheet).

The TMDL provisions in Part IV and Attachments K-S of the Order incorporate compliance schedules consistent with the associated TMDL implementation schedule to achieve the final WQBELs and/or receiving water limitations for the pollutants addressed by the TMDL. For EPA established TMDLs where there is no state program of implementation, Permittees must comply with the WQBELs as of the effective date of the Order in the following circumstances: 1) if the WLAs assigned to MS4 discharges was based on existing pollutant loads at the time the 301 Order WQ 2015-0075, p. 14.

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TMDL was established, meaning that no reduction in pollutant load was required or 2) Permittees are already in compliance with the WQBEL. (For additional information on the implementation of EPA established TMDLs in the Order see the discussion in Part VI.F of this Fact Sheet.) For all TMDLs with implementation schedules established in a state program of implementation, Permittees may comply with these provisions directly or through a Watershed Management Program as described in subparts 2 and 3 below. Compliance with TMDL implementation schedules may also be used as an alternative means to demonstrate compliance with the receiving water limitations in Part V of the Order for the waterbody-pollutant combination addressed by the TMDL as described in subpart 2 below.

For waterbody pollutant combinations not addressed by TMDL, Permittees are subject to the receiving water limitations in Part V of the Order. Permittees may comply with these provisions directly or through a Watershed Management Program as described below.

2. Alternative Demonstrations of Compliance with Certain Receiving Water Limitations Using a TMDL Implementation Schedule
The Los Angeles Water Board recognizes that, in the case of impaired waters subject to a TMDL, the permit’s receiving water limitations for the pollutants addressed by the TMDL may be exceeded during the period of TMDL implementation. Therefore, the Order provides, in Part X.B.1.a, that a Permittee in full compliance with the applicable TMDL requirements in the Order, including the compliance schedules, shall be deemed in compliance with the receiving water limitations provisions in Part V of the Order for the particular pollutant-waterbody combination addressed by the TMDL. Permittees may take advantage of this compliance path without implementing a Watershed Management Program.

3. Alternative Demonstrations of Compliance Using A Watershed Management Program
The provisions in Part IX of the Order to allow Permittees to develop a Watershed Management Program to address certain TMDL provisions in Part IV.B and Attachments K-S of the Order as well as the receiving water limitations in Part V of the Order using watershed, regional, and jurisdictional strategies. Watershed Management Programs are discussed in greater detail in Part X of this Fact Sheet.

As discussed in Part VI.F of this Fact Sheet, Watershed Management Programs may not be used to address Trash or pollutants addressed by a U.S. EPA TMDL that does not require a load reduction. For each of the drainage areas covered by a Watershed Management Program, the Watershed Management Program must either demonstrate that strategies, control measures, and BMPs cumulatively retain the runoff volume of the 85th percentile, 24-hour storm event for the drainage area tributary to the applicable receiving water, or for areas not addressed as aforementioned, shall include a Reasonable Assurance Analysis (RAA) to demonstrate that applicable WQBELs and receiving water limitations shall be achieved through implementation of other watershed control measures. The RAA must be quantitative and performed using a peer-reviewed model in the public domain. For WQBELs and receiving water limitations associated with a TMDL, the objective of the RAA is to demonstrate that the selected water quality control measures will achieve the applicable TMDL provisions. In the case of WQBELs and receiving water limitations not addressed by a TMDL implementation plan

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(either because there is no TMDL or because its U.S. EPA TMDL without a state adopted program of implementation), the objective of the RAA is to demonstrate the ability of the selected water quality control measures in the Watershed Management Program to ensure that Permittees’ MS4 discharges do not cause or contribute to exceedances of applicable WQBELs and receiving water limitations.

A Permittee opting to use a Watershed Management Program to comply with WQBELs and receiving water limitations in Part IV.B and Attachments K-S of the Order and/or the receiving water limitations Part V of the Order demonstrates compliance by implementing the applicable actions and schedules in its approved Watershed Management Program for a waterbody-pollutant combination. For waterbody-pollutant combinations addressed by a TMDL, any schedule in the Watershed Management Program must be consistent with any applicable compliance schedule in the permit, which is based on the TMDL implementation schedule, unless a TSO has been approved by the Los Angeles Water Board for a waterbody-pollutant combination in that TMDL. For pollutants not addressed by a TMDL, or where there is no TMDL implementation schedule, Permittees may incorporate control measures to address the exceedance provided that the Watershed Management Program incorporates a final date for achieving the applicable WQBEL and/or receiving water limitation.

Given the significant time and effort required to develop and implement a Watershed Management Program, the Order allows Permittees to be deemed in compliance with WQBEL(s) and/or receiving water limitation(s), irrespective of actual attainment of the applicable limitation. Permittees are only deemed in compliance with these limitations up until the final deadline for the achievement of the relevant WQBEL(s) and/or receiving water limitation(s) in the Watershed Management Program. Permittees may not be deemed in compliance with TMDL deadlines that have passed, unless a TSO has been approved by the Los Angeles Water Board for a waterbody-pollutant combination in that TMDL, or unless they have chosen to comply with TMDL-based requirements by retaining all nonstormwater runoff and the volume of stormwater runoff from the 85th percentile 24- hour storm and the Permittee is continuing to engage in monitoring and adaptive management through an approved Watershed Management Program.

A Permittee that fails to meet any requirement or date for its achievement related to implementation of an approved Watershed Management must directly comply with the provisions of Part IV.B, Part V, and Attachments K-S of the Order for the waterbody-pollutant combination(s) that should have been addressed by that requirement unless the Permittee requests and receives an extension through a modification of its Watershed Management Program or a Time Schedule Order as discussed below in Part XI.E. The Los Angeles Water Board understands that the implementation of the actions, milestones, and schedules in a Watershed Management Program may depend on a host of factors (e.g. funding, staff resources, etc.). As such, the Order adds provisions authorizing minor deviations from the actions, milestones, and schedules in an approved WMP provided certain conditions are met.

4. Direct Demonstrations of Compliance
Direct compliance with WQBELs and/or receiving water limitations is determined by verification through monitoring that the TMDL provisions in Part IV.B and Attachments K-S of the Order and/or the receiving water limitation provisions in

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Parts V.A and B have been achieved. The Order provides Permittees with several means of demonstrating direct compliance with applicable WQBELs and receiving water limitations. In general, compliance is established by either showing that the discharge or the receiving water is in compliance with the applicable limit for a specific waterbody-pollutant combination or that there was no discharge from a Permittee’s MS4 outfall(s) during the relevant time period. Additionally, in some instances compliance with receiving water limitations and/or WQBELs may be excused when the exceedance is the result of an authorized non-stormwater discharge identified in Part III.A.2 of the Order.

C. WQBELs and Receiving Water Limitations for Trash
For trash, a Permittee may demonstrate compliance with an applicable TMDL through one of any lawful means. Compliance options typically fall into one of four compliance options: Full Capture (Part IV.B.3.b.i of the Order), Mass Balance (Part IV.B.3.b.ii of the Order), Scientifically Based Alternative (Part IV.B.3.b.iii of the Order), or Minimum Frequency of Assessment and Collection (Part IV.B.3.b.iv of the Order). These provisions are discussed in further detail in Part VI.E of this Fact Sheet. For areas not subject to a TMDL and that are not addressed through a WMP, a Permittee may use compliance with the discharge prohibition as evidence of compliance with the receiving water limitations in Part V of the Order in priority land use areas, equivalent alternate land uses and designated land uses only.

D. Commingled Discharges
Due to the inherently complex and interconnected nature of MS4s, this permit assigns joint responsibility to Permittees to meet the requirements of the Order. “Joint responsibility” means that the Permittees that have commingled MS4 discharges are responsible for implementing programs in their respective jurisdictions, or within the MS4 for which they are an owner or operator, to meet the WQBELs and/or receiving water limitations assigned to such commingled MS4 discharges.

In these cases, federal regulations state that co-permittees need only comply with permit conditions relating to discharges from the MS4 for which they are owners or operators. (40 CFR § 122.26(a)(3)(vi).) Individual Permittees are only responsible for their contributions to the commingled discharge. The Order does not require a Permittee to individually ensure that a commingled MS4 discharge meets the applicable WQBELs included in the Order unless such Permittee is shown to be solely responsible for the exceedances.

Part X.D of the Order includes provisions identifying how Permittees with commingled discharges may clarify and distinguish their individual contributions and demonstrate that its MS4 discharge did not cause or contribute to an exceedance of an applicable WQBEL and/or receiving water limitation. If such a demonstration is made, though the Permittee’s discharge may commingle with that of other Permittees, the Permittee would not be held jointly responsible for the exceedance of the applicable limitation. Individual Permittees who demonstrate compliance with the applicable at the limitations will not be held responsible for violations by non-compliant Permittees.

Given the interconnected nature of most Permittees’ MS4s, Permittees are required to work cooperatively to control the contribution of pollutants from one portion of the MS4 to another portion of the system through inter-agency agreements or other formal arrangements as set forth in 40 CFR section 122.26(d)(2)(i)(D).

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E. Time Schedule Orders
This section generally discusses under what circumstances a Time Schedule Order (TSO) may be requested. Under Water Code 13300, a Permittee may submit for the Los Angeles Water Board’s consideration a time schedule setting forth the actions it will take to address an actual or threatened discharge of waste in violation of permit requirements. If the discharge of waste implicates a violation subject to the mandatory minimum penalty provisions in Water Code section 13385(h) or (i), a TSO issued pursuant to 13385(j)(3) may be considered. TSOs issued pursuant to Water Code sections 13300 and/or 13385(j)(3) do not provide protection from potential citizen suits.

In the Order, TSOs will typically be considered where a Permittee determines that its MS4 discharge may not meet WQBELs and/or receiving water limitations in Part IV.B and Attachments K through S and Part V of the Order for which (1) final TMDL compliance deadlines have passed as listed in Table F-26, or (2) no compliance schedule has been provided in the Order. Nothing in this section prevents the Los Angeles Water Board from issuing a TSO pursuant to Water Code section 13300, when appropriate. During the term of the 2012 Los Angeles County MS4 Permit, the Los Angeles Water Board issued three TSOs for various Permittees to comply with bacteria requirements.302
Permittees may individually request a TSO or may jointly request a TSO with all Permittees subject to the WQBELs and/or receiving water limitations. Requests must be made far enough in advance to allow for evaluation of the request, submittal of additional information if necessary, drafting, public comment, and issuance by the Los Angeles Water Board, which may require a publicly noticed meeting. To ensure that enough information is provided to the Los Angeles Water Board to evaluate the request and, if appropriate, draft a TSO, Part X.E.5 of the Order specifies the information that must be included in the request.

Permittees are not guaranteed to receive a TSO or a WMP modification and Permittees should not rely on the certainty of a deadline extension. Permittees are strongly encouraged to implement control measures that will in fact get them into compliance with applicable deadlines.

The Los Angeles Water Board does not intend to take enforcement action against a Permittee for violations of specific WQBELs and/or receiving water limitations if a Permittee is fully complying with the requirements of a TSO to resolve exceedances of the WQBELs and/or receiving water limitations for the specific pollutant(s) in the MS4 discharge.

XII. RATIONALE FOR MONITORING AND REPORTING REQUIREMENTS The Monitoring and Reporting Program (MRP) (Attachment E of the Order) establishes monitoring, reporting, and recordkeeping requirements that implement the federal and state laws and/or regulations. Monitoring, and reporting of the monitoring results as well as other information on implementation of permit requirements are critical components of the Order.

Monitoring is performed to determine compliance with the Order, identify sources of pollutants in MS4 discharges, assess and improve the effectiveness of BMPs and other pollutant control measures, and characterize pollutant loading in MS4 discharges and receiving water. “Without clear monitoring objectives and a detailed monitoring plan, it will 302 TSO No. R4-2014-023 (later amended in TSO No. R4-2014-023-A01), TSO No. R4-2014-0142, and TSO No. R4-2015-0108.

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be difficult for permittees and permitting authorities to evaluate the effectiveness of the municipal stormwater program.”303
The following provides the legal, factual, technical, and policy rationales for the monitoring and reporting requirements contained in the Order and MRP.

The structure of the MRP follows the 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits. For the most part, the substantive requirements from all three previous permits have been carried over to the MRP, and any significant changes are discussed below. Requirements in the MRP apply to all Permittees unless otherwise specified.

A. Legal Authorities Supporting Monitoring and Reporting

1. Authorities Supporting Monitoring and Reporting Generally Sections 308(a) and 402(a)(2) of the federal Clean Water Act304, and 40 CFR sections 122.41(h), (j)-(l), 122.44(i), and 122.48 require that all NPDES permits specify monitoring and reporting requirements and establish substantive monitoring and reporting requirements for NPDES permits. Federal regulations applicable to large and medium MS4s also specify additional monitoring and reporting requirements. (40 CFR §§ 122.26(d)(2)(i)(F) & (d)(2)(iii)(D), 122.42(c).) California Water Code section 13383 further authorizes the Los Angeles Water Board to establish monitoring, inspection, entry, reporting, and recordkeeping requirements.305
The regulations specific to monitoring and reporting requirements for MS4 discharges are prescriptive and require the permitting agency to include requirements for both stormwater and non-stormwater effluent sampling at representative outfalls, representative receiving water monitoring, sampling of specific pollutants, monitoring at specified intervals (e.g., at least three storm events per year), use of analytical methods specified in 40 CFR Part 136, use of field collection methods (e.g., grab vs. composite samples), among other requirements.306
As the Ninth Circuit Court of Appeal stated in a case concerning the 2001 Los Angeles County MS4 Permit (Order No. 01-182): “First and foremost, the Clean Water Act requires every NPDES permittee to monitor its discharges into the navigable waters of the United States in a manner sufficient to determine whether 303 U.S. EPA, MS4 Permit Improvement Guide, p. 97 (April 2010, EPA 833-R-10-001); NPDES Permit Writers’ Manual (2010) at p. 8-2, section 8.1.1.
304 CWA § 308(a) mandates, in part, that “the Administrator shall require the owner or operator of any point source to (i) establish and maintain such records, (ii) make such reports, (iii) install, use, and maintain such monitoring equipment or methods (including where appropriate, biological monitoring methods), (iv) sample such effluents (in accordance with such methods, at such locations, at such intervals, and in such manner as the Administrator shall prescribe), and (v) provide such other information as he may reasonably require…” CWA § 402(a)(2) mandates that “[t]he Administrator shall prescribe conditions for such permits to assure compliance with the requirements of paragraph (1) of this subsection, including conditions on data and information collection, reporting, and such other requirements as he deems appropriate.”
305 See, In the Matter of the Petitions of The City of Oceanside, Fallbrook Public Utilities District, and the Southern California Alliance of Publicly Owned Treatment Works, For Review of WDR Order Nos. R9- 2019-0166 [NPDES No. CA0107433] and R9-2019-0169 [NPDES No. CA0108031] (“Fallbrook”), State Water Board Order WQ 2021-0005, at p. 12-13, n. 31 (the plain language of section 13383 provides the Water Boards with authority to establish monitoring and reporting requirements for MS4 discharges). 306 40 CFR § 122.26(d)(2).

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it is in compliance with the relevant NPDES permit….That is, an NPDES permit is unlawful if a permittee is not required to effectively monitor its permit compliance.”307 The Court also stated:

But while otherwise more flexible than the traditional NPDES permitting system, nothing in the MS4 permitting scheme relieves permittees of the obligation to monitor their compliance with their NPDES permit in some fashion…Rather, EPA regulations make clear that while ms4 NPDES permits need not require monitoring of each stormwater source at the precise point of discharge, they may instead establish a monitoring scheme “sufficient to yield data which are representative of the monitored activity...”308 The federal authority described herein mandates that the Los Angeles Water Board impose a monitoring and reporting program on MS4 permittees that is sufficient to determine compliance with permit terms, as with all NPDES permittees.

In part, federal regulation requires MS4 Permittees, specifically, to “[c]arry out all inspection, surveillance and monitoring procedures necessary to determine compliance and noncompliance with permit conditions including the prohibition on illicit discharges to the municipal separate storm sewer,” including a “monitoring program for representative data collection for the term of the permit that describes the location of outfalls or field screening points to be sampled (or the location of instream stations) …”309 The Regional MS4 Permit MRP requirements, including the receiving water monitoring during wet and dry weather and stormwater and non-stormwater outfall-based monitoring, are necessary to meet these federal requirements. Further, because the Los Angeles Region is characterized by two distinct periods, wet weather and dry weather, the frequency of monitoring required by the MRP, generally three wet weather events and two dry weather events per year, is necessary to meet federal requirements for representative data collection.

The MRP provides definitions to guide data collection during wet weather conditions to ensure it is representative.

Additionally, federal regulations require that a program to detect and remove illicit discharges includes “on-going field screening activities during the life of the permit” and “procedures to be followed to investigate portions of the separate storm sewer system that … based on the results of the field screen, or other appropriate information, indicate a reasonable potential of containing illicit discharges … (such procedures may include: sampling procedures …)…”310 Therefore, the MRP provisions that pertain to non-stormwater screening and outfall monitoring requirements, are necessary to meet this federal requirement.

2. Monitoring Is Necessary to Assess BMP Effectiveness
Assessment of BMP implementation and effectiveness is specifically required by federal regulations at 40 CFR sections 122.26(d)(2)(v) and 122.42(c)(3).311 Specifically, section 122.26(d)(2)(v) requires an assessment of controls [BMPs] 307 Natural Resources Defense Council v. County of Los Angeles (9th Cir. 2013) 725 F.3d 1194, 1207, cert. den. (citing CWA § 402(a)(2) and 40 CFR §§ 122.44(i)(1) and 122.26(d)(2)(i)(F) (emphasis in original).) 308 Id., at p. 1209 (citations omitted; emphasis in original) (citing CWA § 402(a)(2) and 40 CFR §§ 122.41(i)(1) and 122.48(b).)
309 40 CFR § 122.26, subds. (d)(2)(i)(F) and (d)(2)(iii)(D). 310 Id., subd. (d)(2)(iv)(B)(2)-(3).
311 40 CFR § 122.42(c) are the additional reporting requirements for MS4 permittees. MS4 permittees are also subject to all reporting requirements that apply to NPDES permittees generally.

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proposed to be implemented as a result of the Permittees’ stormwater quality management programs, while section 122.42(c)(3) requires that Permittees revise the assessment of their stormwater quality management program as necessary in each annual report based on actual program implementation outcomes (e.g., water quality monitoring data, reduction in non-stormwater discharges, changes in public behavior, BMP effectiveness data).312 Furthermore, 40 CFR section 122.41(h), which applies to all NPDES permits, including MS4 permits, requires that the permittee furnish to the permitting agency any information that it requests to determine compliance with the permit.

Additionally, a 2008 U.S. EPA publication, “Evaluating the Effectiveness of Municipal Stormwater Programs,” states that “EPA stormwater regulations require that the effectiveness of the SWMP [Storm Water Management Program] be evaluated, including assessment of SWMP implementation, evaluation of BMP effectiveness, and the extent to which improvements in storm water outfall discharge quality have occurred.”313
Monitoring and reporting requirements to evaluate BMP effectiveness are included in U.S. EPA issued MS4 Permits issued to the District of Columbia314, Middle Rio Grande,315 and Boise/Garden City.316 Inclusion of similar provisions in U.S. EPAissued permits further supports the Los Angeles Water Board’s determination that federal law requires the inclusion of monitoring and reporting requirements in the permit to evaluate BMP effectiveness.

Federal regulations direct tracking and reporting of “[t]he status of implementing the components of the storm water management program that are established as permit conditions;” “[a] summary of data, including monitoring data, that is accumulated throughout the reporting year;” and “[a] summary describing the number and nature of enforcement actions, inspections, and public education programs,” among others.317
Further, U.S. EPA’s MS4 Permit Improvement Guide states:

An important part of any municipal storm water program is to document and track information on activities the permittee undertakes to comply with the Permit Requirements … In addition, adequate tracking is necessary to generate and provide reports of program progress not only to the permitting authority, but to a permittee’s internal management for planning and funding 312 Note also that 40 CFR § 122.34(d)(1) dictates that permits “must require the permittee to evaluate compliance with the terms and conditions of the permit, including the effectiveness of the components of its storm water management program, and the status of achieving the measurable requirements in the permit.”
313 U.S. EPA, Evaluating the Effectiveness of Municipal Stormwater Programs. 314 See U.S. EPA, NPDES Permit No. DC0000221, Authorization to Discharge Under the National Pollutant Discharge Elimination System, Municipal Separate Storm Sewer System Permit, issued to the District of Columbia (Oct. 7, 2011), Part 6.2.1, pp. 39-40.
315 See U.S. EPA, NPDES Permit No. NMR04AOOO, Authorization to Discharge Under the National Pollutant Discharge Elimination System, Municipal Separate Storm Sewer System Permit, issued to the Middle Rio Grande Watershed (Dec. 22, 2014), Parts III.A and III.B.3, pp. 1, 7 of Part III. 316 See U.S. EPA, NPDES Permit No. IDS-027561, Authorization to Discharge Under the National Pollutant Discharge Elimination System, Municipal Separate Storm Sewer System Permit, issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3 (Dec. 12, 2012), Part IV.C.3.c(ii)-(iii), p. 47. 317 40 CFR § 122.42(c)(1), (c)(4), and (c)(6).

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purposes … To assist the permittee in ensuring appropriate data is gathered and analyzed, the permitting authority should be very clear regarding annual reporting requirements.318
U.S. EPA’s guide also suggests the following model MS4 permit provision, “Within the first [insert time frame which corresponds to the development of the monitoring program e.g. first two years of permit], the permittee must develop a tracking system to track the information required in the permit as well as the information required to be reported in the annual report.”319

3. Federal Requirements for Non-Stormwater Outfall-Based Screening and Monitoring
Phase I (see 40 CFR 122.26 (d)(1)(v)(B) and (d)(1)(iv)(B)) and Phase II stormwater management programs (see 40 CFR 122.26(d)(2)(iv)(B)) are required to address illicit discharges into the MS4. An illicit discharge is defined as any discharge to a municipal separate storm sewer system that is not composed entirely of storm water, except allowable discharges pursuant to an NPDES permit (40 CFR 122.26(b)(2)). In addition to requiring permittee to have the legal authority to prohibit non-stormwater discharges from entering storm sewers (CWA Section 402(p)(3)(B)(ii)), MS4 permits must also require the development of a comprehensive, proactive Illicit Discharge Detection Elimination (IDDE) program.”320
The Los Angeles Water Board has incorporated the Non-Stormwater Outfall-Based Screening and Monitoring Program and crossover requirements of the Illicit Discharge Detection and Elimination Program into the Regional MS4 Permit per the following federal requirements:

Clean Water Act section 402(p)(3)(B)(ii) states that permits “shall include a requirement to effectively prohibit non-stormwater discharges into the storm sewers;…”
40 CFR section 122.26(d)(2)(i)(F) requires the applicant for a Phase I MS4 permit demonstrate they have legal authority to “carry out all inspection, surveillance and monitoring procedures necessary to determine compliance and noncompliance with permit conditions including the prohibition on illicit discharges to the municipal separate storm sewer.”
40 CFR section 122.26(d)(2)(iv)(B)(2) requires a program to detect and remove illicit discharges and improper disposal that includes “(2) A description of procedures to conduct on-going field screening activities during the life of the permit, including areas or locations that will be evaluated by such field screens;…”
40 CFR section 122.41(j)(1) states “samples and measurements taken for the purpose of monitoring shall be representative of the monitored activity.” 40 CFR section 122.42(c) requires the owner or operator of an MS4 to submit an annual report that includes in part “(1) The status of implementing the components of the storm water management program that are established as 318 U.S. EPA, MS4 Permit Improvement Guide, Chapter 8, p. 96. 319 Id., at p. 95.
320 U.S. EPA. 2010. MS4 Permit Improvement Guide. Office of Water, Office of Wastewater Management, Water Permits Division. April. 2010. P. 24, Ch. 3.

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permit conditions; (2) Proposed changes to the storm water management programs that are established as permit condition. Such proposed changes shall be consistent with §122.26(d)(2)(iii) of this part…”, “(4) A summary of data, including monitoring data, that is accumulated throughout the reporting year…”, and “(6) A summary describing the number and nature of enforcement actions, inspections, and public education programs…” 40 CFR section 122.48(b), requires that all permits shall specify “[r]equired monitoring including type, intervals, and frequency sufficient to yield data which are representative of the monitored activity including, when appropriate, continuous monitoring;...”
B. General Monitoring Provisions
As explained in Attachment D at Part III, all monitoring, sampling, sample preservation, and analyses must be conducted according to sufficiently sensitive test procedures approved under 40 CFR Part 136 for the analysis of pollutants, unless another test procedure is required under 40 CFR subchapter N or is otherwise specified in the Order for such pollutants. (40 CFR § 122.41(j)(4); 40 CFR § 122.21(e)(3); 79 Fed. Reg. 49001 (Aug. 19, 2014).) If a Permittee fails to use a lab that can conduct the most sensitive test method set forth in 40 CFR Part 136 for a particular pollutant, then the Permittee will be in violation of the monitoring and reporting requirements.

The General Monitoring Provisions section of the MRP carries over standard monitoring requirements from the previous permits with updates where necessary. The MRP requires Permittees to submit a written request for any modifications to monitoring and reporting requirements in the MRP including an approved Monitoring Program to the Executive Officer of the Los Angeles Water Board for approval. The previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits had similar requirements in Part IX.G.5 of Attachment E for non-stormwater discharges. This is also consistent with the standard practice in these two previous permits where Permittees would submit monitoring and reporting program modification requests to the Los Angeles Water Board for Executive Officer approval. The previous 2010 Ventura County MS4 Permit included prescribed monitoring requirements that were not customizable and, therefore, Permittees could not request substantive modifications. Rather, the EO on behalf of the Los Angeles Water Board could modify the MRP as necessary.

Analytical procedure requirements in the previous permits were updated in the MRP of the Order. The most important changes, which are reflected in Attachment E, include the following:

First, the MRP no longer requires Permittees to test for Aroclors. Instead, at a minimum, it requires analyzing all 55 PCBs congeners listed in Table A-7 of the Water Quality Control Plan for Enclosed Bays and Estuaries – Part 1, Sediment Quality Provisions, using a high-resolution EPA method.

The MRP also requires the laboratories analyzing monitoring samples to be certified by the State Water Board Environmental Laboratory Accreditation Program (ELAP), and requires that Permittees include quality assurance/quality control data with their reports.

This provision is a standard requirement in NPDES permits. ELAP certified labs must

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be compliant with lab methods in 40 CFR Part 136 therefore assuring the Los Angeles Water Board that data collected meets federal standards. 321
Part XIV.J of the MRP of the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit included a requirement for Permittees to provide to the Los Angeles Water Board upon request, standard operating procedures (SOP). For clarity, a requirement in the MRP of the Regional MS4 Permit was added requiring Permittees to continue to develop and maintain a SOP.

C. Monitoring Programs
The MRP requires the Los Angeles County Permittees to continue implementing their most recent Monitoring Program listed in Table E-1 of the MRP, and the Ventura County Permittees to amend their existing monitoring program to include additional TMDL and monitoring station requirements in a Monitoring Program consistent with the provisions of the MRP.

The MRP also allows Permittees to implement a customized monitoring program with the primary objective of allowing for the customization of the outfall monitoring programs and that achieves the five Primary Objectives set forth in Part I.A of the MRP and includes the elements set forth in Part I.C of the MRP. When proposing a customized monitoring program, the Permittees must provide sufficient justification for each element of the program that differs from the monitoring program as set forth in the MRP. The MRP provides options for each Permittee to individually develop and implement an Integrated Monitoring Program (IMP), or alternatively, Permittees may cooperate with other Permittees to develop a Coordinated Integrated Monitoring Program (CIMP). Both the IMP and CIMP are intended to facilitate the effective and collaborative monitoring of receiving waters, stormwater, and non-stormwater discharges and to report the results of monitoring to the Los Angeles Water Board.

The IMP and CIMP requirements within the MRP largely summarize the requirements and reinforce that, at a minimum, the IMP or CIMP must address all TMDL and nonTMDL monitoring requirements of the Order, including receiving water monitoring, stormwater outfall based monitoring, and non-stormwater outfall-based monitoring.

Both the IMP and CIMP approach provide opportunities to increase the cost efficiency and effectiveness of the Permittees monitoring program as monitoring can be designed, prioritized and implemented on a watershed basis. The IMP/CIMP approach allows the Permittees to prioritize monitoring resources between watersheds based on TMDL compliance schedules, and coordinate outfall-based monitoring programs and implement regional studies (if participating). Cost savings can also occur when Permittees coordinate their monitoring programs with other Permittees.

The previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits’ IMPs and CIMPs, the City of Rolling Hills’ non-stormwater Monitoring Program, and the two Board directed individual monitoring programs (for Compton and Gardena) are incorporated in Table E-1 of the MRP by reference. In the MRP, the cities of Compton and Gardena are required to develop an IMP or join a CIMP. The Los Angeles Water Board does not intend to issue a Board directive to these two Permittees unless their IMP is not approved. Los Angeles County Permittees including the City of Long Beach with an existing Monitoring Program(s) shall submit an updated Monitoring Program(s) to the Los Angeles Water Board for approval to incorporate the modifications in 321 Sotelo, Christine. State Water Board California Environmental Laboratory Accreditation Program.

Updates to California ELAP Field of Testing Forms. May 31, 2019.

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requirements of the MRP, and specifically, to be consistent with the requirements in Attachments K through S of the Order. The most recent approved Monitoring Programs shall remain in effect until the Executive Officer of the Los Angeles Water Board approves the updated ones. If the updated and/or the new Monitoring Program(s) are disapproved, the Executive Officer of the Los Angeles Water Board will issue a monitoring directive for the Permittee(s).

Ventura County Permittees are required to submit a new IMP or CIMP or join an existing CIMP for Los Angeles Water Board approval. The TMDL Monitoring Plans listed in Table E-2 of the MRP, which are applicable to Ventura County Permittees, shall remain in effect until the Executive Officer of the Los Angeles Water Board approves the IMP(s) or CIMP(s). Approved TMDL Monitoring Plans by Watershed Management Area that were approved by the Executive Officer of the Los Angeles Water Board prior to the effective date of the Order are incorporated into the Order by reference. If the updated and/or the new Monitoring Program(s) are disapproved, the Executive Officer of the Los Angeles Water Board will issue a monitoring directive for the Permittee(s).

D. Monitoring Locations for Ventura County MS4 Permittees

1. Receiving Water Monitoring Location
The receiving water monitoring locations listed in Table E-3 of the MRP were in the previous 2010 Ventura County Permit. Ventura County Permittees shall include these locations in their IMP or CIMP and shall continue to monitor at these locations. Ventura County Permittees may propose additional and/or alternative receiving water monitoring locations in their IMP or CIMP. In addition, Ventura County Permittees shall propose a receiving water monitoring location in Malibu Creek subwatershed within Ventura County in their IMP or CIMP. The proposed location must be representative of the impacts from MS4 discharges. The 2010 Ventura County MS4 Permit did not have a receiving water station within Malibu Creek subwatershed. Therefore, to assess MS4 impacts on receiving water within the Malibu Creek subwatershed, the Los Angeles Water Board is adding a requirement to add a receiving water monitoring location for that subwatershed.

Mass Emission stations were designed to identify pollutant loads to the ocean, and long-term trends in pollutant concentrations, and characterize surface water quality in major receiving waters. The three Mass Emission stations are located in the major Ventura County watersheds: Calleguas Creek (ME-CC), Ventura River (MEVR), and Santa Clara River (ME-SCR). Stations ME-CC and ME-VR were installed and monitored for the first time during the 2000/01 monitoring season, while MESCR was first installed and monitored during the 2001/02 monitoring season. High flows during January and February of 2005 resulted in the relocation of the ME-VR due to landslide activity and associated safety concerns to approximately one mile downstream from the historical ME-VR site to the Ojai Valley Sanitation District's Treatment Plant above the POTW outfall. The relocated station on the Ventura River (ME-VR2) was first monitored using portable sampling equipment in May 2005; and by September 2005 a permanent station was established. Stations MECC, ME-SCR, and ME-VR/ ME-VR2 were required to sample for 6 monitoring events per year, including a minimum of 2 dry weather samples during the permit term. The samples from stations ME-CC and ME-VR/ ME-VR2 are composed of flow-based composite and toxicity grab samples, and samples from station MESCR are composed of time-based composite samples and toxicity grab samples.

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All three Mass Emission stations collected wet and dry weather water quality samples and analyzed for chronic toxicity.

2. Shoreline Monitoring Locations
The 2010 Ventura County MS4 Permit included various shoreline monitoring locations. The MRP of the Regional MS4 Permit also includes shoreline monitoring locations, which are listed in Table E-4 of the MRP. Note that some locations in the MRP are different from the previous Permit. These new monitoring sites were initially proposed by Ventura County MS4 Permittees in an email dated September 1, 2016 because they are considered “MS4 impacted sites.” MS4 impacted sites are defined as beaches that are within 400 yards322 of municipal storm drain outfalls (not including discharges from creeks, rivers, or estuaries). In a meeting with Ventura County on July 15, 2016 Los Angeles Water Board staff concurred with Ventura County that the proposed monitoring stations were appropriate except shoreline monitoring location 42000 (Ormond Beach at J Street Drain, now Tsumas Creek). This location is not included in the MRP because MS4 discharges do not reach the ocean most of the year but are captured by the Ormond Beach lagoon.

The Ormond Beach lagoon only breaches to the ocean in large storm events, and when it does, the outlet can move hundreds of yards up and down the beach. Also note that Ventura County Permittees are now required to monitor only for fecal coliform (or E. coli)323 and enterococcus consistent with the Ocean Plan Amendment for inclusion of Bacteria Provisions.

3. Stormwater Outfall-Based Monitoring Locations
The stormwater outfall monitoring locations listed in Table E-5 of the MRP were in the previous 2010 Ventura County Permit. Ventura County Permittees shall include these locations in their IMP or CIMP and continue to monitor at these locations.

Ventura County Permittees may propose additional and/or alternative stormwater outfall monitoring locations in their IMP or CIMP. In addition, the Permittee(s) are required to propose an outfall monitoring location in Malibu Creek subwatershed within Ventura County in their IMP or CIMP. Monitoring at this proposed location is important to demonstrate compliance at the proposed receiving water location in Malibu Creek subwatershed within Ventura County.

E. Receiving Water Monitoring Requirements
General requirements are listed for all Permittees in this section. The requirements are similar to the previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits. Table E-6 of the MRP includes a suite of constituents that all Permittees are required to monitor. Ventura County Permittees were required to monitor for similar suite of constituents in their previous Attachment G of the 2010 Ventura County MS4 Permit.

The purpose of receiving water monitoring is to measure the effects of stormwater and non-stormwater discharges from the MS4 to the receiving water, to identify water quality exceedances, to evaluate compliance with TMDL WLAs and receiving water limitations, and to evaluate whether water quality is improving, staying the same or declining. 322 The 400-yard criterion is used by the Ventura County Environmental Health Department. 323 Appendix III of the Ocean Plan authorizes regional water boards to substitute testing for fecal coliform with E. coli when there is sufficient information “to support comparability with approved methods.” (Appendix III, Standard Operating Procedures, § 11, p. 92.)

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1. Receiving Water Monitoring Stations
Receiving water monitoring is linked to outfall-based monitoring to gauge the effects of MS4 discharges on receiving water. Receiving water monitoring stations must be downstream of outfall monitoring stations.

The IMP, CIMP, or stand-alone receiving water monitoring program (in the case of a Board directed jurisdictional monitoring program) must include a map identifying proposed wet weather and dry weather monitoring stations. Receiving water monitoring stations may include historical mass emission stations, TMDL compliance monitoring stations, and other selected stations. The Permittee must describe how monitoring at the proposed locations will accurately characterize the effects of the discharges from the MS4 on the receiving water during both wet weather and dry weather, and meet other stated objectives. The proposed program must also state whether historical mass emission stations will continue to be monitored, and if not, provide sufficient justification for discontinuation of monitoring at the historical mass emissions stations, and describe the value of past receiving water monitoring data in performing trends analysis to assess whether water quality is improving, staying the same or declining.

2. Minimum Wet and Dry Receiving Water Monitoring Requirements Receiving waters are to be monitored during both dry and wet weather conditions to assess the impact of non-stormwater and stormwater MS4 discharges on receiving waters. Wet weather and dry weather are defined in each watershed, consistent with the definitions in TMDLs approved within the watershed. In the previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 permits, Permittees were required to conduct monitoring during three wet and two dry weather events. Ventura County Permittees were required to conduct monitoring during three wet and one dry weather events in their 2010 Permit. This Regional MS4 Permit retained the wet and dry weather definitions from the previous Los Angeles County and the City of Long Beach Permits. Wet weather receiving water monitoring is to commence as soon as possible (within 6 hours) of linked outfall monitoring to be reflective of potential impacts from MS4 discharges. At a minimum, the parameters to be monitored and the monitoring frequency are the same as those required for the linked outfalls.

3. Reporting Levels
The previous permits specified Minimum Levels (MLs) for monitoring stormwater constituents. MLs correspond to the approved analytical methods for reporting a sample result either from Appendix 4 of the SIP in accordance with section 2.4.2 of the SIP or established in accordance with section 2.4.3 of the SIP. The ML represents the lowest quantifiable concentration in a sample based on the proper application of method-based analytical procedures and the absence of any matrix interferences. Other factors may be applied to the ML depending on the specific sample preparation steps employed. For example, the treatment typically applied in cases where there are matrix-effects is to dilute the sample or sample aliquot by a factor of ten. In such cases, this additional factor must be applied in the computation of the Reporting Level (RL). The Method Detection Limit (MDL) is the minimum concentration of a substance that can be measured and reported with 99 percent confidence that the analyte concentration is distinguishable from method blank results, as defined in 40 C.F.R. part 136, Appendix B.

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In general, the MDL is lower than the RL (typically half the RL). In contrast to the previous permits where required MLs were specified, the Regional MS4 Permit no longer specifies required Reporting Levels (RLs) in the MRP. Rather, the Regional MS4 Permit specifies recommended Reporting Levels (RLs) in the MRP for monitoring stormwater constituents. This change from MLs to RLs allows the provision to be more user-friendly therefore streamlining Board staff data analysis efforts and related enforcement. Additionally, per Part II.H.1 of the MRP, Permittees are required to use the most sufficiently sensitive EPA-approved lab analytical methods available consistent with requirements in Attachment D of the Order (see, 40 CFR § 122.21(e)(3); 79 Fed. Reg. 49001 (Aug. 19, 2014).). Per Part II.H.7 of the MRP, recommended RLs are intended to serve as guidance for Permittees to choose the most sufficiently sensitive test method to attain RLs that are less than or equal to the lowest applicable water quality standard.

Information considered to incorporate recommended RLs in the MRP include previous permits’ MLs, water quality goals324, and other information provided by labs. In determining what is the lowest water quality goal, standards that apply to drinking water and water for agricultural use were not considered because they do not apply to stormwater. On August 5, 2016, Ventura County Permittees as a follow-up item to the July 15, 2016 meeting with Board staff, provided information on the lowest MDLs and RLs that their labs can achieve. However, this information was not considered because Ventura County Permittees stated in a follow-up email on June 9, 2020 that they included drinking water and non-40 CFR methods to try to get RLs low enough to meet the Permit MLs. They further stated that some of the stormwater methods (e.g. EPA 625) frequently require dilutions due to the turbid nature of stormwater, so they often end up with RLs higher than quoted due to matrix issues.

To solicit more information about lab methods for stormwater samples, Board staff also looked at information from ELAP certified labs in Los Angeles County. Using information from the State Board’s Drinking Water Program325, Board staff compiled a list of 14 ELAP certified labs within Los Angeles County. Board staff contacted each lab with a list of constituents in Table F-27 below and requested the labs to report their lowest MDL and RL values for stormwater samples along with the pertinent analytical method. Two of the 14 labs reported that they do not perform stormwater analysis. Of the twelve remaining labs, six labs did not respond. The other six labs326 responded by submitting the requested information.

However, while six labs responded with the requested information, not all of them analyze all the constituents listed in Table F-27 below.

Board staff used the lowest MDL and RL values received from these labs to populate Table F-27 below. When water quality goal or lab information was 324 In this context, water quality goals include any objectives, criteria, targets, or limits within TMDLs, California Toxics Rule (CTR), Basin Plan, Ocean Plan, ISWEBE, and other water quality values found on the State Water Board Water Quality Goals searchable database at http://www.waterboards.ca.gov/water_issues/programs/water_quality_goals/search.shtml. 325 The State Board provides this information using an interactive GIS map at:
https://waterboards.maps.arcgis.com/apps/webappviewer/index.html?id=bd0bd8b42b1944058244337b d2a4ebfa
326 Between April 2020 and June 2020, the six labs that submitted the requested information were Advanced Technology Laboratories, Alpha Scientific Corporation, American Scientific Laboratories, Enviro-Chem, Inc., Positive Lab Service, and Weck Laboratories, Inc.

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unavailable, Board staff looked at RLs and MDLs in CEDEN data for the Surface Water Ambient Monitoring Program (SWAMP). For many constituents, the recommended RLs in the Regional MS4 Permit were set equal to the previous permit MLs. Where the water quality goal was lower than the previous permit ML, and a lab could achieve a lower RL using a more sensitive analytical method, the recommended RL was set equal to the lowest lab RL. However, for PCBs, the recommended RLs were set equal to the lowest water quality goals. The table below indicates the MLs in the previous permits, the recommended RLs included in the Regional MS4 Permit, and the basis for the recommended RL. Under “Basis for Recommended RL”, “no change” indicates that the recommended RL was set equal to the ML from the previous permits. The term “Lowest WQ Goal” indicates that the recommended RL was set equal to the lowest water quality goal. The term “Lowest Lab RL” was set equal to the lowest recommended RL considering the lowest MDL a lab could achieve.

The previous MS4 Permits required Total Suspended Solids (TSS) monitoring but did not require Suspended Sediment Concentration (SSC) to be monitored as part of the table of constituents below. However, studies conducted by the United States Geological Survey (USGS) have found that the TSS procedure may not capture the full range of sediment particle sizes contributing to sediment impairments. 327 Therefore, both TSS and SSC are required to be monitored for in the MRP.

Also, note that dissolved phosphorus was replaced with orthophosphate as P (dissolved) in the MRP. In general, phosphorus exists in two main forms in water; dissolved (soluble) and particulate. Orthophosphate is the primary dissolved form of phosphorus that is more bioavailable to algae and aquatic plants.

With regards to PCBs, previous MS4 Permits required monitoring for Aroclors.

Permittees in practice inconsistently monitored for Aroclors and/or congeners.

Therefore, the Regional MS4 Permit MRP does not require Permittees to test for Aroclors (with subsequent reporting of total PCBs concentrations based on the sum of the Aroclor concentrations). Moreover, RLs for Aroclors are very high and detections are extremely rare. Additionally, the relevant total PCBs concentrations of concern for protection of human health and aquatic life are extremely low and detection of these low concentrations can only be achieved through using methods which analyze for individual PCB congeners (the various Aroclors were composed of mixes of multiple congeners in addition to other constituents at times). Thus, the MRP requires at a minimum analyzing all 55 PCBs congeners listed in Table A-7 of the Water Quality Control Plan for Enclosed Bays and Estuaries – Part 1, Sediment Quality Provisions. Furthermore, Permittees are encouraged to use a high resolution EPA-approved method which attains a reporting level of at least

0.00002 µg/L (20 pg/L) for ocean waters per congener, and 170 pg/L for non-ocean marine waters and freshwater per congener. Using a high-resolution EPA method along with analyzing for a minimum of 55 congeners will result in fewer non-detects, which will allow for the ability to conduct trend analyses of PCBs in the Region. In addition, higher resolution PCB monitoring using congeners will aid in “fingerprinting” potential sources through providing information on PCB homologs (those congeners with the same number of chlorines). The goal is to identify 327 Gray, John et, al. US Geological Survey. Comparability of Suspended-Sediment and Total Suspended Sediment Data. August 2000.

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sources and eventually eliminate this highly persistent legacy pollutant from the watersheds.

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Table F-27. Rationale for Recommended Reporting Levels (RLs) in the Regional MS4 Permit328

CONSTITUENTS
Lowest Lab MDL in ELAP
Certified Los Angeles
County Labs
Lowest Lab RL in ELAP
Certified Los Angeles
County Labs
Lab Method for ELAP
Certified Los Angeles
County Labs
Lowest Water Quality
Goal329
Previous Permits MLs
Regional MS4 Permit
Recommended RLs
Basis for Recommended RL

CONVENTIONAL
POLLUTANTS mg/L mg/L - mg/L mg/L mg/L -
Oil and Grease

0.28 Enviro
Chem
1 EnviroChem
EPA
1664A - 5 5 No change
Total Phenols 0.00016
Weck

0.001
Weck
EPA
624.1 - 0.1 0.1 No change
Cyanide 0.0038
Weck

0.005
Weck
EPA
335.4

0.0052 /

0.001 (CTR -
freshwater /
saltwater)

0.005 0.005 No change
pH 0.1
Weck

0.1 Weck
SM
4500H+
B
- 0-14 0-14 units No change
Temperature - - - - N/A N/A No change
Dissolved Oxygen 0.1 0.5 SM
2580B
5 (Basin
Plan)
Sensitivity to
5 mg/L N/A Field measurement
328 Table Abbreviations: CTR = California Toxics Rule; EPA Rec. = National Recommended Water Quality Criteria; ISWEBE = Inland Surface Waters, Enclosed Bays, and Estuaries (ISWEBE) Plan; TMDL = Total Maximum Daily Load; HH = Human Health; WQ = Water Quality. 329 Water quality goals include any objectives, criteria, targets, or limits within TMDLs, California Toxics Rule (CTR), Basin Plan, Ocean Plan, ISWEBE, and other water quality values found on the State Water Board Water Quality Goals searchable database at http://www.waterboards.ca.gov/water_issues/programs/water_quality_goals/search.shtml.

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ATTACHMENT F – FACT SHEET F-267 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
American
Scientific
Lab
American
Scientific
Lab
BACTERIA MPN/100
ml MPN/100 ml - MPN/100 ml MPN/100 ml MPN/100 ml -
Total coliform 1.8
Weck

1.8 Weck SM 991B 1,000 (TMDL) 10,000 Not required
Removed
requirement
for
consistency
with ISWEBE
& Ocean Plan
Enterococcus 1
Weck

1.8 Weck
SM
9230B
30 (ISWEBE
& Ocean
Plan)
104 30 Lowest WQ
Goal
Fecal coliform 1.8
Weck

1.8 Weck
SM
9221E
200
(Bacteria
Provisions–
Ocean Plan)
400 200 Lowest WQ
Goal
E. coli 1.8
Weck

1.8 Weck
SM
9221F
100
(Bacteria
Provisions–

ISWEBE)
235 100 Lowest WQ
Goal
GENERAL mg/L mg/L - mg/L mg/L mg/L -

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ATTACHMENT F – FACT SHEET F-268 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Orthophosphate as P
(Dissolved) 0.003 Weck 0.01 Weck EPA 365.3 -

0.05 (formerly
Dissolved
Phosphorus)

0.05 No change
Total Phosphorus

0.0063
Advanced
Tech Lab

0.02 Advanced
Tech Lab
EPA
365.3 0.1 (TMDL) 0.05 0.05 No change
Turbidity

0.5 Positive
Lab

0.5 Positive Lab
EPA
180.1 - 0.1 NTU 0.1 NTU No change
Total Suspended Solids
(TSS)
2 Alpha
Scientific
4 Alpha
Scientific
SM
2540D - 2 2 No change
Total Dissolved Solids
(TDS)
1 Positive
Lab
5 Positive Lab
SM
2540E
250 (Basin
Plan) 2 2 No change
Suspended Sediment
Concentration (SSC)
1 Positive
Lab
5 Positive Lab
ASTM
D3977-
97 - Not required 5 Lowest lab RL
Volatile Suspended
Solids
1 Positive
Lab
5 Positive Lab
SM
2540E - 2 Not required Removed Requirement

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ATTACHMENT F – FACT SHEET F-269 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Total Organic Carbon
(TOC) 0.073 Weck 0.1 Weck SM 5310B - 1 1 No change
Dissolved Organic
Carbon (DOC) 0.016 Weck 0.1 Weck SM 5310B - Not required 0.2

SWAMP RL
(MDL is 0.1
using EPA
415.1M)
Total Petroleum
Hydrocarbon

1.53 Advanced
Tech Lab
2 Advanced
Tech Lab
EPA
1664A - 5 5 No change
Biochemical Oxygen
Demand (BOD) 2 Weck 2 Weck EPA 5210B - 2 2 No change
Chemical Oxygen
Demand (COD)

2.43 Enviro
Chem
5 EnviroChem
SM
5220D - 20-900 20
Low end of
previous
permit ML
range
Total Ammonia-Nitrogen

0.016
Advanced
Tech Lab

0.03 Advanced
Tech Lab
ASTM
D1426-
08A

0.1 (Basin
Plan) 0.1 0.1 No change
Total Kjeldahl Nitrogen 0.018
Weck

0.1 Weck
EPA
351.2 - 0.1 0.1 No change
Nitrate+Nitrite

0.01 Enviro
Chem

0.05 EnviroChem
SM
4500-
NO3-E
5 (TMDL) 0.1 0.1 No change

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ATTACHMENT F – FACT SHEET F-270 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Alkalinity

0.031
Enviro
Chem
1 EnviroChem
SM
2320B - 2 2 No change
Specific Conductance

0.005
Positive
Lab

0.005
Positive Lab
EPA
120.1 - 1 umho/cm 1 umho/cm No change
Total Hardness 0.016
Weck

0.1 Weck
EPA
200.7 - 2 2 No change
MBAS

0.01 Positive
Lab

0.02 Positive Lab
SM
5540C

0.5 (Basin
Plan) 0.5 0.5 No change
Chloride

0.2 Positive
Lab

0.4 Positive Lab
EPA
300.0
10 (Basin
Plan) 2 2 No change
Fluoride 0.009
Weck

0.1 Weck
EPA
300.0
2 (Basin
Plan-MCL) 0.1 0.1 No change
Methyl tertiary butyl
ether (MTBE)

0.00026
Advanced
Tech Lab

0.0005
Advanced
Tech Lab
EPA
624.1

0.013 (Basin
Plan-MCL) 1 0.013 Lowest WQ Goal
Perchlorate

0.00109
Advanced
Tech Lab

0.002
Advanced
Tech Lab
EPA
314.0

0.006 (Basin
Plan-MCL) 0.004 0.006 Lowest WQ Goal
METALS (Dissolved &
Total) µg/L µg/L - µg/L µg/L µg/L -

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ATTACHMENT F – FACT SHEET F-271 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Aluminum 1.3
Weck
5 Weck
EPA
200.8
1000 (Basin
Plan-MCL) /
87 (EPA rec.
–
freshwater)
100 87 Lowest WQ
Goal
Antimony 0.045
Weck

0.5 Weck
EPA
200.8
6 (Basin
Plan-MCL) /

5.6 (EPA
Rec. – HH)

0.5 0.5 No change
Arsenic 0.074
Weck

0.4 Weck
EPA
200.8
8 (Ocean
Plan) / 0.018
(EPA Rec. –
HH)
1 1 No change
Beryllium 0.033
Weck

0.1 Weck
EPA
200.8

0.033
(Ocean
Plan)

0.5 0.5 No change
Cadmium 0.041
Weck

0.1 Weck
EPA
200.8
1 (Ocean
Plan) 0.25 0.25 No change
Chromium (total) 0.035
Weck

0.2 Weck
EPA
200.8
2 (Ocean
Plan) 0.5 0.5 No change
Chromium (Hexavalent) 0.0079
Weck

0.02 Weck
EPA
218.6
2 (Ocean
Plan) 5 2
Lowest WQ
Goal
Copper 0.13
Weck

0.5 Weck
EPA
200.8
>9 (CTRfreshwater 0.5 0.5 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *637
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-272 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
hardnessbased)
Iron 1.1
Weck
10 Weck
EPA
200.7
300 (EPA
Rec.- HH) 100 100 No change
Lead 0.031
Weck

0.2 Weck
EPA
200.8
>2.5 (CTRfreshwater
hardnessbased)

0.5 0.5 No change
Mercury 0.017
Weck

0.05 Weck
EPA
245.1

0.04 (Ocean
Plan) 0.5 0.04 Lowest WQ Goal
Nickel 0.045
Weck

0.8 Weck
EPA
200.8
>52 (CTRfreshwater
hardnessbased)
1 11.88 No change
Selenium 0.14
Weck

0.4 Weck
EPA
200.8

5.0 (TMDL &
CTRfreshwater) /

1.5 (EPA
Rec. –
freshwater)
1 1 No change
Silver 0.062
Weck

0.2 Weck
EPA
200.8
>3.4 (CTRfreshwater
hardnessbased)

0.25 0.25 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *638
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-273 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Thallium 0.014
Weck

0.2 Weck
EPA
200.8

1.7 (CTR –
HH) / 0.24
(EPA Rec. –
HH)
1 0.24 Lowest WQ
Goal
Zinc 0.94
Weck
5 Weck
EPA
200.8
20 (Ocean
Plan) 1 1 No change

SEMIVOLATILE

ORGANIC

COMPOUNDS - ACIDS
µg/L µg/L - µg/L µg/L µg/L -
2-Chlorophenol 0.28
Weck
1 Weck
EPA
625.1
1 (Ocean
Plan) / 0.1
(EPA Rec. –
HH)
2 1 WQ Goal
4-Chloro-3-methylphenol
(3-Methyl-4-
Chlorophenol)

0.23 Weck
1 Weck
EPA
625.1
1 (Ocean
Plan) 1 1 No change
2,4-Dichlorophenol 0.26
Weck
1 Weck
EPA
625.1
1 (Ocean
Plan) / 0.3
(EPA Rec. –
HH)
1 1 WQ Goal
2,4-Dimethylphenol 0.3
Weck
1 Weck
EPA
625.1
30 (Ocean
Plan) 2 2 No change
2,4-Dinitrophenol 0.4 1 8270C 4 (Ocean
Plan) 5 4
Lowest WQ
Goal

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *639
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-274 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
American
Scientific
American
Scientific
2-Nitrophenol 0.26
Weck
1 Weck
EPA
625.1
30 (Ocean
Plan) 10 10 No change
4-Nitrophenol

0.5 American
Scientific
1 American
Scientific
8270C 30 (Ocean
Plan) 5 5 No change
Pentachlorophenol

0.2 American
Scientific
1 American
Scientific
8270C

0.28 (CTR –
HH) / 0.03
(EPA Rec. –
HH)
2 1 Lowest lab RL
Phenol 0.16
Weck
1 Weck
EPA
625.1
30 (Ocean
Plan) 1 1 No change
2,4,6-Trichlorophenol 0.22
Weck
1 Weck
EPA
625.1

0.29 (Ocean
Plan) 10 1 Lowest lab RL

SEMIVOLATILE

ORGANIC
COMPOUNDS –BASE /

NEUTRAL
µg/L µg/L - µg/L µg/L µg/L -
Acenaphthene 0.38
Weck
1 Weck
EPA
625.1
1,200 (CTRHH) / 20
(EPA Rec. –
HH)
1 1 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *640
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-275 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Acenaphthylene 0.17
Weck
1 Weck
EPA
625.1

0.0088
(Ocean
Plan)
2 1 Lowest lab RL
Anthracene 0.12
Weck
1 Weck
EPA
625.1

0.0088
(Ocean
Plan)
2 1 Lowest lab RL
Benzidine 1.4
Weck
10 Weck
EPA
625.1

0.000069
(Ocean
Plan)
5 5 No Change
1,2 Benzanthracene
(Benzo(a)anthracene)

0.19 Weck
1 Weck
EPA
625.1

0.0044
(CTR-HH) /

0.0012 (EPA
Rec. – HH)
5 1 Lowest lab RL
Benzo(a)pyrene 0.39
Weck
1 Weck
EPA
625.1

0.0044
(CTR-HH) /

0.00012
(EPA Rec. –
HH)
2 1 Lowest lab RL
Benzo(g,h,i)perylene
(1,12-benzoperylene)

0.42 Weck
2 Weck
EPA
625.1

0.0088
(Ocean
Plan)
5 2 Lowest lab RL
3,4 Benzofluoranthene
(benzo[b]fluoranthene)

0.46 Weck
1 Weck
EPA
625.1

0.0044
(CTR-HH) / 10 1 Lowest lab RL

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *641
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-276 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL

0.0012 (EPA
Rec. – HH)
Benzo(k)fluoranthene 0.22
Weck
1 Weck
EPA
625.1

0.0044
(CTR-HH) 2 1 Lowest lab RL
Bis(2-chloroethoxy)
methane

0.25 Weck 1 Weck EPA 625.1

4.4 (Ocean
Plan) 5 4.4 Lowest WQ Goal
Bis(2-chloroisopropyl)
ether

0.38 Weck
1 Weck
EPA
625.1
122 (EPA
Rec. –
freshwater)
2 2 No change
Bis(2-chloroethyl) ether 0.27
Weck
1 Weck
EPA
625.1

0.031 (CTR
– HH) / 0.03
(EPA Rec.

HH)
1 1 No change
Bis(2-ethylhexyl)
phthalate

1.69 Advanced
Tech Lab
5 Advanced
Tech Lab
EPA
625.1

1.8 (CTR –
HH) / 0.32
(EPA Rec. –
HH)
5 5 No change
4-Bromophenyl phenyl
ether

0.36 Weck
1 Weck
EPA
625.1
122 (EPA
Rec. -
freshwater
toxicity
chronic)
5 5 No change
Butyl benzyl phthalate
(Benzyl butyl phthalate)

0.18 Weck
1 Weck
EPA
625.1
3,000 (CTR
– HH) / 0.1 10 1 Lowest lab RL

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *642
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-277 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
(EPA Rec. –
HH)
2-Chloroethyl vinyl ether
1 Positive
Lab
1 Positive Lab
EPA
625.1 - 1 1 No change
2-Chloronaphthalene 0.45
Weck
1 Weck
EPA
625.1
1,700 (CTR -
HH) / 7.5
(EPA Rec. –
saltwater
toxicity
acute)
10 7.5 Lowest WQ
Goal
4-Chlorophenyl phenyl
ether

0.41 Weck
1 Weck
EPA
625.1 - 5 5 No change
Chrysene 0.19
Weck
1 Weck
EPA
625.1

0.0044 (CTR
-HH) 5 1 Lowest lab RL
Dibenzo(a,h)anthracene

0.5 Positive
Lab
1 Positive Lab
EPA
625.1

0.0044 (CTR
-HH) /

0.00012
(EPA Rec. –
HH)

0.1 0.1 No change
1,3-Dichlorobenzene 0.42
Weck
1 Weck
EPA
625.1
400 (CTR –
HH) / 7 (EPA
Rec. – HH)
1 1 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *643
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-278 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
1,4-Dichlorobenzene 0.48
Weck
1 Weck
EPA
625.1
5 (Basin
Plan-MCL) 1 1 No change
1,2-Dichlorobenzene 0.46
Weck
1 Weck
EPA
625.1
600 (Basin
Plan-MCL) /
50 (EPA
Rec. –
freshwater
toxicity
other)
1 1 No change
3,3’-Dichlorobenzidine 0.99
Weck
5 Weck
EPA
625.1

0.0081
(Ocean
Plan)
5 5 No change
Diethyl phthalate 0.15
Weck
1 Weck
EPA
625.1
23,000 (CTR
-HH) / 3
(EPA Rec. –
freshwater
toxicity
chronic)
2 2 No change
Dimethyl phthalate 0.18
Weck
1 Weck
EPA
625.1
313,000
(CTR – HH)
/ 3 (EPA
Rec. –
freshwater
2 2 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *644
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-279 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
toxicity
chronic)
di-n-Butyl phthalate 0.1
Weck
1 Weck
EPA
625.1
2,700 (CTR
– HH) 3
(EPA Rec. –
freshwater
toxicity
chronic)
10 3
Lowest WQ
Goal
2,4-Dinitrotoluene 0.18
Weck
1 Weck
EPA
625.1

0.11 (CTR –
HH) / 0.049
(EPA Rec. –
HH)
5 1 Lowest lab RL
2,6-Dinitrotoluene 0.27
Weck
1 Weck
EPA
625.1
230 (EPA
Rec. –
freshwater
toxicity
chronic)
5 5 No change
4,6 Dinitro-2-
methylphenol (2-Methyl4,6-dinitrophenol)

1.4 Weck
5 Weck
EPA
625.1

13.4 (CTR –
HH) / 2 (EPA
Rec. – HH)
5 5 No change
1,2-Diphenylhydrazine 0.3
Weck
1 Weck
EPA
625.1

0.04 (CTR –
HH) / 0.03
(EPA Rec. –
HH)
1 1 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *645
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-280 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
di-n-Octyl phthalate 0.46
Weck
1 Weck
EPA
625.1
3 (EPA Rec.
– freshwater
toxicity
chronic)
10 3
Lowest WQ
Goal
Fluoranthene 0.08
Weck
1 Weck
EPA
625.1
15 (Ocean
Plan) 0.05 0.05 No change
Fluorene 0.35
Weck
1 Weck
EPA
625.1

0.0088
(Ocean
Plan)

0.1 0.1 No change
Hexachlorobenzene 0.49
Weck
1 Weck
EPA
625.1

0.00021
(Ocean
Plan) /

0.000079
(EPA Rec. –
HH)
1 1 No change
Hexachlorobutadiene 0.47
Weck
1 Weck
EPA
625.1

0.44 (CTR -
HH) / 0.01
(EPA Rec. –
HH)
1 1 No change
Hexachlorocyclopentadiene0.98
Weck
1 Weck
EPA
625.1
50 (Basin
Plan-MCL) /
1 (EPA Rec.
– HH)
5 1
Lowest WQ
Goal

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *646
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-281 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Hexachloroethane 0.5
Weck
1 Weck
EPA
625.1

1.9 (CTR –
HH) / 0.1
EPA Rec. –
HH)
1 1 No change
Indeno(1,2,3-c,d)pyrene

0.5 Positive
Lab
1 Positive Lab
EPA
625.1

0.0044
(CTR-HH) /

0.0012 (EPA
Rec. - HH)

0.05 0.05 No change
Isophorone 0.21
Weck
1 Weck
EPA
625.1

8.4 (CTR –
HH) 1 1 No change
Naphthalene 0.49
Weck
1 Weck
EPA
625.1
620 (EPA
Rec. –
freshwater
toxicity
chronic)

0.2 0.2 No change
Nitrobenzene 0.36
Weck
1 Weck
EPA
625.1

4.9 (Ocean
Plan) 1 1 No change
N-Nitrosodimethyl amine 0.5
Weck
1 Weck
EPA
625.1

0.00069
(CTR – HH) 5 1 Lowest lab RL
N-Nitrosodiphenyl amine 0.19
Weck
1 Weck
EPA
625.1

2.5 (Ocean
Plan) 1 1 No change
N-Nitrosodi-n-propyl
amine

0.26 Weck
1 Weck
EPA
625.1

0.005 (CTR -
HH) 5 1 Lowest lab RL

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *647
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-282 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Phenanthrene 0.32
Weck
1 Weck
EPA
625.1

0.0088
(Ocean
Plan)

0.05 0.05 No change
Pyrene 0.25
Weck
1 Weck
EPA
625.1

0.0088
(Ocean
Plan)

0.05 0.05 No change
1,2,4-Trichlorobenzene 0.49
Weck
1 Weck
EPA
625.1

0.071 (EPA
Rec.- HH) 1 1 No change

CHLORINATED
PESTICIDES µg/L µg/L - µg/L µg/L µg/L -
Aldrin

0.004
Positive
Lab

0.005
Positive Lab
EPA
608.3

0.000022
(Ocean
Plan) /

0.00000077
(EPA Rec. –
HH)

0.005 0.005 No change
alpha-BHC

0.002
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.0039 (CTR
-HH) 0.01 0.01 No change
beta-BHC

0.004
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.004
(Ocean Plan
for HCH)

0.005 0.005 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *648
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-283 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
delta-BHC

0.004
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.004
(Ocean Plan
for HCH)

0.005 0.005 No change
gamma-BHC (lindane)

0.003
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.004
(Ocean Plan
for HCH)

0.02 0.01 Lowest lab RL
alpha-chlordane

0.0029
Advanced
Tech Lab

0.025
Advanced
Tech Lab
EPA
608.3

0.000023
(Ocean Plan
for total
chlordane) /

0.00059
(TMDL)

0.1 0.025 Lowest lab RL
gamma-chlordane

0.0014
Advanced
Tech Lab

0.025
Advanced
Tech Lab
EPA
608.3

0.000023
(Ocean Plan
for total
chlordane) /

0.00059
(TMDL)

0.1 0.025 Lowest lab RL
4,4'-DDD

0.007
Positive
Lab

0.025
Positive Lab
EPA
608.3

0.00017
(Ocean Plan
for DDTs) /

0.00012
(EPA Rec. –
HH) /

0.05 0.025 Lowest lab RL

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *649
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-284 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL

0.00059
(TMDL)
4,4'-DDE

0.007
Positive
Lab

0.025
Positive Lab
EPA
608.3

0.00017
(Ocean Plan
for DDTs) /

0.00059
(TMDL) /

0.000018
(EPA Rec. –
HH)

0.05 0.025 Lowest lab RL
4,4'-DDT

0.0025
Positive
Lab

0.005
Positive Lab
EPA
608.3

0.00017
(Ocean Plan
for DDTs) /

0.00003
(EPA Rec. –
HH)

0.01 0.005 Lowest lab RL
Dieldrin

0.0025
Positive
Lab

0.005
Positive Lab
EPA
608.3

0.00004
(Ocean
Plan) /

0.0000012
(EPA Rec. –
HH)

0.01 0.005 Lowest lab RL
alpha-Endosulfan 0.0032 0.025
Positive Lab
EPA
608.3

0.0087 (CTR
– saltwater) 0.02 0.02 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *650
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-285 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Advanced
Tech Lab
beta-Endosulfan

0.0025
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.0087 (CTR
– saltwater) 0.01 0.01 No change
Endosulfan sulfate

0.002
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.009
(Ocean Plan
for
endosulfan) /

0.0087 (EPA
Rec. –
saltwater)

0.05 0.01 Lowest lab RL
Endrin

0.0025
Positive
Lab

0.005
Positive Lab
EPA
608.3

0.002
(Ocean
Plan)

0.01 0.005 Lowest lab RL
Endrin aldehyde

0.003
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.76 (CTR -
HH) 0.01 0.01 No change
Heptachlor

0.001
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.00005
(Ocean
Plan) /

0.0000059
(EPA Rec. –
HH)

0.01 0.01 No change

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *651
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-286 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Heptachlor Epoxide

0.002
Positive
Lab

0.01 Positive Lab
EPA
608.3

0.00002
(Ocean
Plan) /

0.000032
(EPA Rec. –
HH)

0.01 0.01 No change
Toxaphene

0.2 Positive
Lab

0.5 Positive Lab
EPA
608.3

0.0002 (CTR
–
freshwater)

0.5 0.5 No change

POLYCHLORINATED
BIPHENYLS µg/L µg/L - µg/L µg/L pg/L -
Congeners - - -

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)
/ 0.000064
(EPA Rec. –
HH)
Not required
20 (ocean
waters) / 170
(non-ocean
marine
waters &
freshwater)
Lowest WQ
Goals
Aroclor-1016

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)

0.5 Not required Removed
requirement

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ATTACHMENT F – FACT SHEET F-287 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
/ 0.000064
(EPA Rec. –
HH)
Aroclor-1221

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)
/ 0.000064
(EPA Rec. –
HH)

0.5 Not required Removed
requirement
Aroclor-1232

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)
/ 0.000064
(EPA Rec. –
HH)

0.5 Not required Removed
requirement
Aroclor-1242

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)

0.5 Not required Removed
requirement

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ATTACHMENT F – FACT SHEET F-288 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
/ 0.000064
(EPA Rec. –
HH)
Aroclor-1248

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)
/ 0.000064
(EPA Rec. –
HH)

0.5 Not required Removed
requirement
Aroclor-1254

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)
/ 0.000064
(EPA Rec. –
HH)

0.5 Not required Removed
requirement
Aroclor-1260

0.15 Positive
Lab

0.25 Positive Lab
EPA
608.3

0.000019
(Ocean
Plan) /

0.00017
(CTR – HH)

0.5 Not required Removed
requirement

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ATTACHMENT F – FACT SHEET F-289 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
/ 0.000064
(EPA Rec. –
HH)

ORGANOPHOSPHATE
PESTICIDES µg/L µg/L - µg/L µg/L µg/L -
Atrazine 0.034
Weck

0.1 Weck
EPA
525.2
1 (Basin
Plan-MCL) 2 1
Lowest WQ
Goal
Chlorpyrifos 0.0069
Weck

0.01 Weck
EPA
625.1M

0.014
(TMDL) /

0.009 (EPA
Rec. –
saltwater)

0.05 0.01 Lowest lab RL
Cyanazine 0.024
Weck

0.1 Weck
EPA
525.2 - 2 2 No change
Diazinon 0.0052
Weck

0.01 Weck
EPA
625.1M

0.1 (TMDL) /

0.05 (EPA
Rec. -
freshwater)

0.01 0.01 No change
Malathion 0.0076
Weck

0.01 Weck
EPA
625.1M

0.1 (EPA
Rec. -
freshwater)
1 0.1 Lowest WQ
Goal
Prometryn 0.036
Weck

0.1 Weck
EPA
525.2 - 2 2 No change

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ATTACHMENT F – FACT SHEET F-290 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Simazine 0.015
Weck

0.1 Weck
EPA
525.2
4 (Basin
Plan-MCL) 2 2 No change
HERBICIDES µg/L µg/L - µg/L µg/L µg/L -
2,4-D

0.14 Weck

0.4 Weck
EPA
515.4
70 (Basin
Plan-MCL) 10 10 No change
Glyphosate 1.8
Weck
5 Weck EPA 547 700 (Basin Plan-MCL) 5 5 No change
Dacthal (DCPA) 0.053
Weck

0.1 Weck
EPA
515.4

0.008 (EPA
Rec. – HH) Not required 0.1 Lowest lab RL
2,4,5-TP (SILVEX) 0.046
Weck

0.2 Weck
EPA
515.4
50 (Basin
Plan-MCL) 0.5 0.5 No change
PYRETHROIDS µg/L µg/L - µg/L µg/L µg/L
Bifenthrin 0.00079
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
Cyfluthrin 0.00083
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
Cypermethrin 0.00066
Weck

0.002
Weck
EPA
8270M

0.002 (EPA
Rec. -
freshwater)
Not required 0.002 Lowest WQ
Goal
Esfenvalerate 0.00098
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
Lambda-cyhalothrin 0.0012
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL

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ATTACHMENT F – FACT SHEET F-291 CONSTITUENTS Lowest Lab MDL in ELAP Certified Los Angeles County Labs Lowest Lab RL in ELAP Certified Los Angeles County Labs Lab Method for ELAP Certified Los Angeles County Labs Lowest Water Quality Goal329 Previous Permits MLs Regional MS4 Permit
Recommended RLs
Basis for Recommended RL
Permethrin 0.005
Weck

0.005
Weck
EPA
8270M

0.001 (EPA
Rec.-
saltwater)
Not required 0.005 Lowest lab RL

FIPRINOL AND ITS
DEGRADATES µg/L µg/L - µg/L µg/L µg/L -
Fipronil 0.002
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
Fiprinol Sulfide 0.002
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
Fiprinol Sulfone 0.002
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
Fiprinol Desulfinyl 0.002
Weck

0.002
Weck
EPA
8270M - Not required 0.002 Lowest lab RL
NEONICOTINOIDS µg/L µg/L - µg/L µg/L µg/L -
Imidacloprid 0.092
Weck

0.5 Weck EPA 538 - Not required 0.5 Lowest lab RL

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F. Stormwater Outfall-Based Monitoring Requirements
The primary purpose of outfall monitoring is to characterize the stormwater MS4 discharges from each Permittee’s drainages within each subwatershed. Outfall-based monitoring is also conducted to assess compliance with WQBELs and receiving water limitations. Factors that may impact stormwater runoff volume include percent effective impervious cover (connected to the storm drain system), vegetation type, soil compaction and soil permeability.

Stormwater outfall monitoring is linked to receiving water monitoring (see Part XII.E of this Fact Sheet). Monitoring must be conducted at least three times per year during qualifying rain events, including the first rain event of the year and conducted concurrently (within 6 hours) before the commencement of the downstream receiving water monitoring. The MRP retained similar wet and dry weather definitions from the previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits. Note that the previous Ventura County Permit had a different wet and dry weather definition in comparison to the 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits. However, to accommodate the differences between the previous permits, the Regional MS4 Permit MRP includes a provision allowing Permittees, if they choose, to propose their own weather condition definition for Executive Officer approval. This flexibility is necessary to accommodate the geographic and climate differences between Los Angeles County and Ventura County.

Monitoring is conducted for pollutants of concern including all pollutants with assigned WQBELs. Parameters to be monitored during wet weather include: flow, pollutants subject to a TMDL applicable to the receiving water, and pollutants listed on the Clean Water Act Section 303(d) list for the receiving water or a downstream receiving water.

Flow is necessary to calculate pollutant loading.

For water bodies listed on the Clean Water Act section 303(d) list as being impaired due to sedimentation, siltation or turbidity, suspended sediment concentration (SSC) must be analyzed. Total suspended solids (TSS) and hardness must be analyzed when metals are monitored. TSS is the parameter most often required in NPDES permits to measure suspended solids.

For freshwater, the following field measurements are also required: pH, dissolved oxygen, temperature, and specific conductivity. Temperature and pH are parameters impacting the effect of pollutants in freshwater (i.e., ammonia toxicity is dependent on pH and temperature). Temperature and dissolved oxygen are interdependent and fundamental to supporting aquatic life beneficial uses. Specific conductivity is a parameter important to assessing potential threats to MUN and freshwater aquatic life beneficial uses.

Note that the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permits included requirements to monitor stormwater discharges for exceedances of municipal action levels (MALs). These requirements are discontinued in the Regional MS4 Permit. At this time, the Los Angeles Water Board has concluded that TMDL requirements and a robust monitoring program provide sufficient criteria to assess the impact of stormwater discharges and therefore, MALs are unnecessary.

Aquatic toxicity monitoring is required in the receiving water once per year during wet weather conditions. Aquatic toxicity is a direct measure of toxicity and integrates the effects of multiple synergistic effects of known and unidentified pollutants. When

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samples are found to be toxic, a Toxicity Identification Evaluation (TIE) must be performed to identify the pollutants causing toxicity. If a toxicant or class of toxicants that is identified through a TIE conducted during wet weather at a receiving water monitoring location, then, Permittees must analyze for the toxicant(s) during the next scheduled sampling event in the discharge from the outfall(s) upstream of the receiving water location.

For many analytical procedures, 40 CFR Part 136 specifies that grab samples must be collected for pH, temperature, dissolved oxygen, and coliform bacteria. The MRP also allows the Permittees to collect specific conductivity and turbidity samples using grab sampling. Federal regulations specify that grab samples must be taken for the abovementioned parameters because they evaluate characteristics that may change during the time necessary for compositing. A grab sample is a single sample collected at a particular time and place that represents the composition of the stormwater only at that time and place. When the quality and flow of the stormwater being sampled is not likely to change over time, a grab sample is appropriate. A composite sample is a collection of individual samples obtained at regular intervals, usually based upon time or flow volume. A composite sample is desirable when the material being sampled varies significantly over time either as a result of flow or quality changes. Flowproportional compositing is usually preferred when effluent flow volume varies appreciably over time.

Sampling requirements, including methods for collecting flow-weighted composite samples, are consistent with provisions set forth in 40 CFR section 122.21(g)(7), which establish specific requirements for collecting flow-weighted composite samples. Per these provisions, the aliquots for flow-weighted composite samples must be collected during a representative storm for the first 3 hours, or for the duration of the storm event if it is less than 3 hours long.

G. Non-Stormwater Outfall-Based Screening and Monitoring Requirements The Non-Stormwater Outfall-Based Monitoring Program is a step-wise framework for identifying illicit discharges and connections and assessing whether Permittees are effectively prohibiting non-stormwater discharges to the MS4. Under previous MS4 Permits for the 2012 Los Angeles County and the 2014 City of Long Beach, Permittees developed a Non-Stormwater Outfall-Based Screening and Monitoring Program. The requirements in the Regional MS4 Permit allow Permittees to build upon past efforts to advance the program and focus monitoring on the most significant areas of nonstormwater quality concerns. Los Angeles County Permittees will continue to implement the existing program, making modifications to address new permit requirements.

Ventura County Permittees are required to submit an IMP/CIMP and explain how the non-stormwater outfall-based screening and monitoring requirements in the MRP will be implemented. Figure F-1 below illustrates the general process for the NonStormwater Outfall-Based Screening and Monitoring Program. The previous permit for Ventura County addressed the need to eliminate illicit discharges through the Illicit Connection and Illicit Discharges program and the Dry Weather Monitoring Program.

Several elements of these programs are similar to the Regional MS4 Permit requirements and in many cases Ventura County Permittees can integrate the new requirements into their existing efforts. The Regional MS4 Permit Non-Stormwater Screening and Monitoring Program requirements establish consistency among all Permittees.

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Figure F-1. Non-Stormwater Outfall-Based Screening and Monitoring Program General Process

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1. Objectives
The objectives listed in Part VII.A of the MRP are based on the federal requirements listed above, including but not limited to Clean Water Act section 402(p)(3)(B)(ii) and 40 CFR section 122.26(d)(2)(i)(F). The purpose of the NonStormwater Outfall-Based Screening and Monitoring Program is to identify and investigate where necessary non-stormwater discharges including illicit discharges, non-stormwater discharges conditionally exempt from the prohibition, and discharges that are issued a separate discharge permit. Program objectives are listed to provide Permittees with guide points as they design and implement their program. Many of the objectives from the previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits are retained but have been updated to build upon past efforts of Permittees. Although the previous permit for Ventura County did not list objectives for analogous programs (Dry-weather Monitoring Program and Illicit Discharge and Detection Program), objectives in Part VII.A of the MRP reflect elements of Ventura County Permittees’ existing programs.

2. Screening and Monitoring Program Procedures and Requirements Parts VII.B through E of the MRP implement federal requirements, including those in 40 CFR section 122.26(d)(2)(i)(F), which require inspection, surveillance, and monitoring to demonstrate compliance with permit conditions. The Non-Stormwater Outfall-Based Screening and Monitoring Program addresses the permit condition prohibiting the discharge of non-stormwater discharges through the MS4 to receiving waters based on Clean Water Act section 402(p)(3)(B)(ii). Requirements in Parts VII.B through E of the MRP are a series of systematic procedures for characterizing non-stormwater discharges and eliminating illicit discharges to ensure compliance with the effective prohibition. The Non-Stormwater OutfallBased Screening and Monitoring Program is intended to maximize the use of the Permittee’s resources by integrating the screening and monitoring process into existing or planned IMP/CIMP efforts of Los Angeles County Permittees including the City of Long Beach. It is also intended to rely on the illicit discharge source investigation and elimination requirements and MS4 mapping requirements for Los Angeles County Permittees including the City of Long Beach, and Ventura County Permittees. Finally, the Regional MS4 Permit builds upon dry-weather monitoring requirements in the previous Ventura County permit. Figure F-1 depicts the process of implementing Non-Stormwater Outfall-Based Screening and Monitoring Program elements.

To implement broader federal requirements for non-stormwater outfall-based screening and monitoring, the Regional MS4 Permit includes clear, specific, measurable requirements to achieve the objectives in Part VII.A of the MRP. U.S.

EPA demonstrates examples of clear, specific, measurable requirements to control non-stormwater discharges in the MS4 Permit Improvement Guide. 330 This
guidance document contains examples of field screening, prioritizing source investigations, mapping (similar to inventory requirements in the Regional MS4 Permit), and monitoring. In addition, the MS4 Program Evaluation Guidance Document, describes important dry weather monitoring program components such as a database for tracking dry-weather outfall inspections and prioritized source 330 U.S. EPA. 2010. MS4 Permit Improvement Guide. Office of Water, Office of Wastewater Management, Water Permits Division. April. 2010. p. 24-34.

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identification of dry-weather discharges.
331 The Compendium of MS4 Permitting
Approaches332 cites permit examples for inventory, prioritization for screening, and monitoring of non-stormwater discharges. Moreover, U.S. EPA issued MS4 permits to the Middle Rio Grande Area and Washington D.C. that require field screening for prioritized areas, comparable to the Regional Permit.333 As the monitored activity is dry weather MS4 discharges, the Regional MS4 Permit defines conditions of dry weather. The 0.1-inch requirement is consistent with U.S.

EPA’s determination of a “measurable” storm event, as indicated in 40 CFR section 122.26(d)(2)(iii)(2) and the NPDES Storm Water Sampling Guidance Document. 334
MS4 permits commonly delineate wet and dry weather at 0.1 inch with 72 hours as a precedent dry period.
335

3. Changes from the Previous Permits
Most of the requirements in Parts VII.B through E of the MRP are continued from previous 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 permits. As described above in this Fact Sheet, the Los Angeles Water Board has determined that these requirements are necessary to comply with federal requirements. The previous 2010 Ventura County permit had a different framework than the Regional MS4 Permit requirements; therefore, some of the specific requirements in Parts VII.B through E of the MRP will require the Ventura County Permittees to perform new or different tasks. However, Ventura County Permittees as explained in subpart a below, have already performed activities under their previous permit requirements that will allow them to tailor their existing efforts to satisfy Regional MS4 Permit requirements. To synchronize programs among the three groups of Permittees, Parts VII.B through E of the MRP include separate schedules for Los Angeles County (including City of Long Beach) Permittees versus Ventura County Permittees, but the requirements are the same.

Other changes from the three previous permits are intended to allow the program to progress beyond earlier screening efforts. The most notable differences are highlighted below.
a. Non-Stormwater Outfall-Based Screening and Monitoring Program The previous 2010 Ventura County Permit addressed non-stormwater discharges through the IDDE program and through the dry-weather monitoring program. The IDDE program requirements required mapping and inventorying of outfalls and field screening for illicit connections to the storm drain system.

Additionally, the previous 2010 Ventura County Permit’s dry weather monitoring program required Permittees to select outfall sites for dry weather 331 U.S. EPA. 2007. MS4 Program Evaluation Guidance. Office of Water, Office of Wastewater Management, Water Permits Division. January 2007. pp.34, 89. 332 Compendium of MS4 Permitting Examples, Part 1: Six Minimum Control Measures. Office of Wastewater Management, Water Permits Division. November 2016. 810-U-16-001. Pp. 12-14. 333 NPDES Permit No. NMR04A000 issued to Middle Rio Grande Watershed, effective December 22, 2014. p. 40; NPDES permit (IDS-027561) issued to Ada County Highway District, Boise State University, City of Boise, City of Garden City. Drainage District #3, and the Idaho Transportation Department District #3.

Effective February 1, 2013. pp. 27-29.
334 U.S. EPA. 1992. NPDES Storm Water Sampling Guidance Document. EPA-833-B-92-001. Office of Water. July 1992. P. 15.
335 For example, NPDES Permit No. CAS612008, issued to San Francisco Bay Region (Order No. R2- 2015-0049, issued November 19, 2015, p. 125) and NPDES Permit No. DC0000221 issued to the Government of the District of Columbia, as modified November 9, 2012, p. 35).

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monitoring based on certain criteria. Monitoring consisted of analytical testing, field measurements and observations at the selected outfall stations. The main difference between the Regional MS4 Permit and the previous Ventura County permit is that the Ventura County Permit focused on screening for illicit connections under the IDDE program, whereas the Regional MS4 Permit MRP, Part VII provides a system of requirements for all non-stormwater discharges. Depending on the nature of the illicit discharge information collected, Ventura County Permittees may have addressed the plan requirements in Part VII of the MRP. Therefore, the Regional MS4 Permit requires Ventura County Permittees to develop a Non-Stormwater OutfallBased Screening and Monitoring Program in their IMP or CIMP that complies with requirements in Parts VII.B through E of the MRP. In this manner, Ventura County Permittees can build upon and advance their existing non-stormwater screening efforts to better control discharges of pollutants to the MS4.

For Los Angeles County Permittees, the non-stormwater program remains largely the same except that this Permit allows to further streamline the requirements.
b. Screening of Outfalls with Significant Non-Stormwater Discharge Part VII.B of the MRP requires identification of significant non-stormwater MS4 discharges. Ventura County Permittees have already collected information under the IDDE program, which will enable them to distinguish significant nonstormwater discharges. This is a necessary step in prioritizing non-stormwater discharges for source identification.

The requirements in Part VII.B of the MRP are retained from the previous permits for Los Angeles County and the City of Long Beach. Part VII.B of the MRP establishes criteria for the Permittees to consider when delineating “significant” non-stormwater discharges and provides flexibility for other factors to be considered. Evidence of ongoing potential illegal dumping or illicit connections must be used along with other criteria based on field and/or laboratory measurements for defining a significant non-stormwater discharge.

Where the Permittee uses other factors, they must provide a definition or a criterion for how a significant non-stormwater discharge will be determined. In particular, the thresholds for field measurements must be specified, (e.g., flow greater than 10 gallons per minute) and/or water quality data (e.g., bacteria counts exceeding a certain level) that will be used to determine whether the non-stormwater discharge is significant.
c. Source Investigation for Outfalls with Significant Non-Stormwater Discharge
Source investigation is ongoing among the Los Angeles County and City of Long Beach Permittees. This is an enhancement for Ventura County Permittees that is a necessary step in eliminating non-stormwater discharges and/or preventing the discharge of pollutants to the MS4. The step is necessary to focus efforts on non-stormwater dischargers with the greatest potential to affect water quality. Once prioritized, Permittees initiate source investigation efforts required under Part VII.C of the MRP.

The requirements in Part VII.C of the MRP are retained from the previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits. The

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previous 2010 Permit for Ventura County included similar requirements in the IDDE program, with some differences in wording. Source investigation from Non-Stormwater Outfall-Based Monitoring Program is conducted simultaneously with IDDE procedures in Part VIII.I of the Order so that sources may be tracked from both an upstream and downstream direction.

Per Part VII.D.2 of the MRP, Permittees within Los Angeles County shall determine if re-screening is necessary for any of the previously screened outfalls with no significant non-stormwater discharge. Rather than requiring re-screening of all outfalls, the Regional MS4 Permit requires a review of dry weather receiving water monitoring data downstream of the outfalls and other relevant information to determine if re-screening is necessary for any of the previously screened outfalls that did not have significant non-stormwater discharge.

Part VII.D.1 of the MRP provides the schedule for Ventura County Permittees to screen their outfalls for significant non-stormwater discharges. This is shorter than what was provided in the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits where they had 3 years from the effective dates of the Orders respectively, to conduct source investigations for no less than 25% of the outfalls in the inventory and 5 years from the effective date of the aforementioned Orders to conduct source investigations for 100% of the outfalls in the inventory. However, the shorter interim schedule (i.e., 3 years for 50% of the outfalls) for Ventura County Permittees in comparison to Los Angeles County Permittees in the previous permits (i.e., 3 years for 25% of the outfalls) is reasonable considering the often isolated MS4 networks for each city in Ventura County and the significantly less number of outfalls in comparison to LA County Permittees.
d. Non-Stormwater Outfall-Based Monitoring
Part VII.E.2 of the MRP allows Los Angeles County Permittees 90 days after completing non-stormwater source investigation to begin monitoring the nonstormwater discharge. These 90 days is the same as previously allowed in the 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits.

Non-stormwater monitoring for Los Angeles County and City of Long Beach Permittees is decreased from previous permits to allow the Permittees flexibility in directing program resources to where they are most effective.

Previous requirements in the 2012 Los Angeles County and 2014 City of Long Beach MS4 permits required sampling at established frequencies unless granted alternative frequencies by the Executive Officer of the Los Angeles Water Board. The Regional MS4 Permit recognizes that in some instances, non-stormwater that has been fully characterized and investigated for illicit discharges remains static in quantity and quality, such that repeated sampling and analyses does not produce useful information. Nevertheless, illicit discharges may recur at any time. To provide monitoring relief while still being proactive in protecting water quality, the Regional MS4 Permit allows the Permittee to record field observations (e.g., visual, presence of odor, etc.), in lieu of analytical testing, for non-stormwater discharges that are: 1) to waters not subject to a TMDL, 2) have been fully characterized and investigated for illicit discharges, and 3) do not cause or contribute to exceedances of water quality standards. This approach is consistent with recommendations in the

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EPA MS4 improvement Guide,
336 which states that for dry weather flows,
permit writers “may consider allowing permittees the flexibility to look for indicators of an illicit discharge before conducting water quality tests due to baseline flow (baseflow, groundwater flow, irrigation return flows) in certain areas. In these cases, permit writers could require that sensory indicators (i.e., odor, color, turbidity, and floatables) be evaluated.”
The previous 2010 permit for Ventura County required the Principal Permittee to select (based on certain criteria) and monitor five outfalls during dry weather at a frequency of once per year. The Regional MS4 Permit allows the Ventura County Permittees to assess their significant non-stormwater discharges and create a prioritization for conducting source identification.

Non-stormwater outfall-based monitoring requirements are also consistent with 40 CFR section 122.41(j)(1), which requires “samples and measurements taken for the purpose of monitoring shall be representative of the monitored activity”. The Regional MS4 Permit requires grab samples be collected for non-stormwater outfall discharges. This is a change from the 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits which required composite samples. Dry weather outfall flows are likely to be consistent in quality such that a grab sample would be representative of the discharge and would require less effort and/or equipment. The EPA Permit Writer’s Manual discusses the appropriateness of grab versus composite samples, stating “Grab samples are appropriate when the flow and characteristics of the wastestream being sampled are relatively constant.”337 In addition, the 2015 EPA Multi-sector General Permit for Industrial Storm water Discharges Associated with Industrial Activity requires grab samples for compliance monitoring, with the exception of some specific receiving waters. 338
Previous permits for Los Angeles County and the City of Long Beach established Non-stormwater Action Levels (NALs) for non-stormwater to gauge potential impact to water quality and to identify the potential need for additional controls for non-stormwater discharges. The Regional MS4 Permit discontinues the use of action levels. During the previous permit term, the majority of Los Angeles County Permittees addressed non-stormwater outfallbased screening and monitoring through WMPs and EWMPs using means other than action levels. Based on practical knowledge gained through implementing the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 permits, the Los Angeles Water Board believes that at this time, TMDL requirements and WQBELs provide sufficient criteria to assess the impact of non-stormwater discharges. This is also consistent with the Ventura Countywide Stormwater Quality Management Program’s339 reapplication 336 U.S. EPA. 2010. MS4 Permit Improvement Guide. Office of Water, Office of Wastewater Management, Water Permits Division. April. 2010. p. 32.
337 U.S. EPA. 2010. NPDES Permit Writer’s Manual. EPA-833-K-10-001. Office of Wastewater Management, Water Permits Division. September 2010. P. 8-7. 338 U.S. EPA. Multi-Sector General Permit for Industrial Storm water Discharges Associated with Industrial Activity. June 4, 2015.
339 The Ventura Countywide Stormwater Quality Management Program is collective term for Ventura County Permittees which include the Ventura County Watershed Protection District, the County of Ventura, and the cities of Camarillo, Fillmore, Moorpark, Ojai, Oxnard, Port Hueneme, Santa Paula, Simi Valley, Thousand Oaks, and Ventura.

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package which states that it “does not support the inclusion of NALs within the next Ventura County MS4 Permit.”340
H. TMDL Monitoring
Like other monitoring and reporting requirements, TMDL-related monitoring is also necessary to implement federal law. The Clean Water Act and its implementing regulations require monitoring and reporting as a major component of all NPDES permits, not just MS4 permits. As a condition of receiving a NPDES permit, a permittee agrees to monitor its discharges to ensure compliance with the permit’s terms.341 Here, this would include any WQBELs or receiving water limitations based on TMDLs.

Further, MS4 permits issued by U.S. EPA support the conclusion that TMDL-related monitoring is a federal requirement for MS4 permits. For example, the District of Columbia MS4 Permit states under Section 5, Monitoring and Assessment of Controls, that the monitoring must meet several objectives, including “any additional necessary monitoring for purposes of source identification and wasteload allocation tracking. This strategy must align with the Consolidated TMDL Implementation Plan….monitoring must be adequate to determine if relevant WLAs are being attained within specified timeframes in order to make modifications to relevant management programs, as necessary.”342
Also note that other local agencies also have TMDL monitoring requirements. The MS4 permit issued to Caltrans requires that Caltrans conduct effluent and receiving water monitoring and implement a “Comprehensive TMDL Monitoring Plan.”343 The Industrial General Storm Water Permit requires industrial facilities to collect samples of their discharge and analyze them for various parameters, including “[a]dditional applicable industrial parameters related to receiving waters with 303(d) listed impairments or approved TMDLs…”344 The NPDES permit for stormwater discharges from Sentinel Peak Resources (Inglewood Oil Field) includes effluent limitations based on TMDLs and corresponding effluent and receiving water monitoring requirements.345 340 Ventura Countywide Stormwater Quality Management Program. Report of Waste Discharge. January 2015.
341 CWA § 402(a)(1) (“the Administrator may, after opportunity for public hearing, issue a permit for the discharge of any pollutant, or combination of pollutants, notwithstanding section 1311(a) of this title, upon condition that such discharge will meet either (A) all applicable requirements under sections 1311, 1312, 1316, 1317, 1318, and 1343 of this title, or (B) prior to the taking of necessary implementing actions relating to all such requirements, such conditions as the Administrator determines are necessary to carry out the provisions of this chapter.”)
342 U.S. EPA, Permit for District of Columbia Municipal Separate Storm Sewer System, Modified Permit No.

DC0000221 (Oct. 7, 2011, mod. Nov. 9, 2012), Part 5, pp. 32-38. 343 State Water Board, Order 2012-0011-DWQ (as amended by Orders WQ 2014-0006-EXEC, WQ 2014- 0077-DWQ, and WQ 2015-0036-EXEC), NPDES Statewide Storm Water Permit, Waste Discharge Requirements for State of California, Department of Transportation, Finding 40, Part E.2.c, and Attachment IV, Section III.A.1.
344 State Water Board, Order No. 2014-0057-DWQ, NPDES General Permit for Storm Water Discharges Associated with Industrial Activities, Part XI.B.6.e, pp. 39-40. 345 Los Angeles Water Board, Order No. R4-2018-0020, NPDES Permit for Sentinel Peak Resources California, LLC Inglewood Oil Field, pp. E-6 to E-9, E-13 to E-15.

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I. Outfall-Based Database
The requirements in the MRP with regards to maintaining an outfall-based database are similar to the previous 2012 Los Angeles County, the 2014 City of Long Beach and 2010 Ventura County Permits.

Per Part VIII.A of the MRP, the Permittee must continue to maintain a map or geographic database of storm drains, channels and outfalls to aid in the development of the outfall monitoring plan and to assist the Los Angeles Water Board in reviewing the logic and adequacy of the number and location of outfalls selected for monitoring. The map/database must include the storm drain network, receiving waters, other surface waters that may impact hydrology, including dams and dry weather diversions. In addition, the map must identify the location and identifying code for each major outfall within the Permittee’s jurisdiction. The map must include overlays including jurisdictional boundaries, subwatershed boundaries and storm drain outfall catchment boundaries.

The map must distinguish between storm drain catchment drainage areas and subwatershed drainage areas, as these may differ. In addition, the map must include overlays displaying land use, impervious area and effective impervious area (if available). To the extent known, outfalls that convey significant non-stormwater discharges per Part VII.B of the MRP, must also be identified on the map, and the map must be updated annually to include the total list of known outfalls conveying significant flow of non-stormwater discharge.

J. Aquatic Toxicity Monitoring Methods
Aquatic toxicity monitoring is required in receiving waters during both wet and dry weather conditions to determine whether designated beneficial uses are fully supported.

Further, Attachment E requires additional monitoring at MS4 outfalls where aquatic toxicity is present above a certain effect level in downstream receiving waters to determine whether MS4 discharges are causing or contributing to the aquatic toxicity.

In this situation, outfall monitoring must either entail monitoring for specific pollutants identified in a TIE in the downstream receiving water, or for aquatic toxicity itself, where the specific pollutants could not be identified through the TIE conducted on the downstream receiving water.

Based on the stated goals of the Clean Water Act, the U.S. EPA and individual states implement three approaches to monitoring water quality. These approaches include chemical-specific monitoring, toxicity testing, and bioassessments (USEPA 1991a). 346

Each of the three approaches has distinct advantages and all three work together to ensure that the physical, chemical, and biological integrity of our waters are protected.

Water quality objectives have been developed for only a limited universe of chemicals.

For mixtures of chemicals with unknown interactions or for chemicals having no chemical-specific objectives, the sole use of chemical-specific objectives to safeguard aquatic resources would not ensure adequate protection. Aquatic life in southern California coastal watersheds are often exposed to nearly 100% effluent from wastewater treatment plants, urban runoff, or stormwater; therefore, toxicity testing and bioassessments are also critical components for monitoring programs as they offer a more direct and thorough confirmation of biological impacts. The primary advantage of using the toxicity testing approach is that this tool can be used to assess toxic effects (acute and chronic) of all the chemicals in aqueous samples of effluent, receiving water, 346 U.S. EPA. 1991a. Technical support document for water quality-based toxics control. Office of Water.

Washington, DC. EPA/505/2-90-001.

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or stormwater. This allows the cumulative effect of the aqueous mixture to be evaluated, rather than the toxic responses to individual chemicals. 347
For freshwater, the MRP requires Permittee(s) to conduct chronic and acute toxicity tests on water samples, by methods specified in Short-term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms (EPA/821/R-02/013, 2002; Table IA, 40 CFR Part 136) and Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms (EPA/821/R-02/012, 2002; Table IA, 40 CFR Part 136), or a more recent edition.

The Los Angeles Water Board has traditionally requested stormwater dischargers to use a list of three organisms – algae, crustacean, and fish - (specifically, Selananstrum capricomutum, Ceriodaphnia dubia, and Pimephales promelas) to screen for the most sensitive species to be used during toxicity testing. This list has been in use for many decades; however, Selanastrum was removed from the screening list due to its almost complete lack of sensitivity and two additional species were added to the MRP: the freshwater amphipod Hyalella azteca and the midge Chironomus dilutes. This is consistent with the approach being used at the San Francisco Regional Water Board where they have also noted that several emerging groups of pesticides, including fipronil, neonicotinoids, and pyrethroids, are increasingly dominating pesticide applications in urban and agricultural environments and the older list of test organisms do not respond to most of these pesticides. Now that urban uses of diazinon have been banned for a decade, highly toxic pyrethroids are more commonly found, and Hyalella azteca is the most sensitive species to that class of chemicals, while Chironomus dilutus is most sensitive to fipronil, which is being observed in urban waters in the State.

Pimephales tended to be most sensitive to ammonia in the past and while ammonia may still at times occur for various reasons, detections at toxic concentrations of the chemical are reduced. Ceriodaphnia is most sensitive to organophosphate pesticides, such as diazinon, which is also less frequently detected at toxic concentrations due to its ban and subsequent reduced use.

During the first year of the permit term, to determine the most sensitive test species, the Permittee(s) shall conduct two wet weather and two dry weather toxicity tests with the species listed in the MRP for freshwater and non-ocean marine waters, as appropriate348. After this screening period, the results of the test species sensitivity screening shall be included in the IMP or CIMP and subsequent monitoring shall be conducted using the most sensitive test species. Sensitive test species determinations shall also consider the most sensitive test species used for proximal receiving water monitoring. The MRP requirements for the most sensitive test species screening are consistent with the previous 2010 Ventura County Permit’s aquatic toxicity requirements. The previous 2012 Los Angeles County and the 2014 City of Long Beach MS4 Permits allowed the Permittees to use a sensitive test species that had already been determined, or if there was prior knowledge of potential toxicant(s), and a test species was sensitive to such toxicant(s). However, due to inconclusive results for toxicity testing, the MRP requires screening for the most sensitive species instead of allowing Permittees to choose species from existing studies.

For non-ocean marine waters, the MRP requires the Permittee(s) to conduct the chronic toxicity test in accordance with U.S. EPA’s Short-Term Methods for Estimating the 347 U.S. EPA, EPA Regions 8, 9, and 10 Toxicity Training Tool, January 2010. 348 Southern California Coastal Water Research Project, Stormwater Monitoring Coalition: Toxicity Testing Laboratory Guidance Document- SCCWRP Technical Report 956, December 2016.

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Chronic Toxicity of Effluent and Receiving Waters to West Coast Marine and Estuarine Organisms, First Edition, August 1995, (EPA/600/R-95/136), or Short Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Third Edition, October 2002, (EPA/821-R-02-014), or a more recent edition. In contrast to the previous MS4 permits, the Regional MS4 Permit no longer requires ocean water aquatic toxicity monitoring because, in light of the other ocean monitoring requirements, and evaluation of data collected under prior permits, aquatic toxicity monitoring was not providing significant added value and the Board understands that aquatic toxicity monitoring is costly. All monitoring included in the Regional MS4 Permit, however, will result in appropriate data needed to evaluate water quality impacts of the discharges and ensure that beneficial uses are protected. Aquatic toxicity monitoring remains in non-marine ocean waters and inland estuarine and surface waters, which gives the Board the information it needs to evaluate toxicity. (See In the Matter of the Petitions of the City of Oceanside, Fallbrook Public Utilities Dist. and the Southern California Alliance of Publicly Owned Treatment Works, State Water Board Order WQ 2021-0005 at pp. 12, 13.)
Furthermore, the toxicity component of the MRP includes toxicity identification procedures so that pollutants that are causing or contributing to acute or chronic effects in aquatic life exposed to these waters can be identified and others can be discounted.

TIEs are needed to identify the culprit constituents to be used to prioritize management actions. Where toxicants are identified in a MS4 discharge, the MRP requires a Toxicity Reduction Plan (TRE).

TRE development and implementation is directly tied to the integrated monitoring programs and watershed management program, to ensure that management actions and follow-up monitoring are implemented when problems are identified. Permittees are encouraged to coordinate TREs with concurrent TMDLs where overlap exists. If a TMDL is being developed or implemented for an identified toxic pollutant, much of the work necessary to meet the objectives of a TRE may already be underway, and information and implementation measures should be shared.

Overall, the toxicity monitoring program will assess the impact of stormwater and nonstormwater discharges on the overall quality of aquatic fauna and flora and implement measures to ensure that those impacts are eliminated or reduced. As stated previously, chemical monitoring does not necessarily reveal the totality of impacts of stormwater on aquatic life and habitat-related beneficial uses of water bodies. Therefore, toxicity requirements are a necessary component of the MS4 monitoring program.

The Los Angeles Water Board provided clarification and recommendations to Permittees for the monitoring programs under the 2012 Los Angeles County MS4 Permit and the 2014 City of Long Beach MS4 Permit regarding aquatic toxicity monitoring, particularly pertaining to the requirement to conduct chronic and acute toxicity tests in dry and wet weather conditions and requirements for conducting a TIE and outfall monitoring. Further clarification was necessary regarding requirements for follow-up monitoring when aquatic toxicity is present in downstream receiving waters. A memo dated August 7, 2015 was sent to all Los Angeles County MS4 Permittees including the City of Long Beach to provide additional clarification and applies to all monitoring directives and IMPs and CIMPs (in Los Angeles County) developed pursuant to Part VI.B of the previous 2012 Los Angeles County MS4 Permit and Part VII.B of the previous 2014 City of Long Beach MS4 Permit. This guidance is provided in Attachment G of the Order and thus now applies to all Permittees including Ventura County.

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K. Regional Studies
The regional studies are optional in this Permit, and are similar to the previous Los Angeles County, the City of Long Beach and Ventura County Permits. Permittees are encouraged to continue to participate in the two regional studies listed below.

1. Southern California Storm Water Monitoring Coalition Watershed Monitoring Program
a. The Southern California Storm Water Monitoring Coalition (SMC) Regional Watershed Monitoring Program was initiated in 2008. This program is conducted in collaboration with the Southern California Coastal Water Research Project (SCCWRP), State Water Board’s Surface Water Ambient Monitoring Program (SWAMP), three Southern California Regional Water Quality Control Boards (Los Angeles, Santa Ana, and San Diego) and several county stormwater agencies (Los Angeles, Ventura, Orange, Riverside, San Bernardino and San Diego). SCCWRP acts as the facilitator to organize the program and completes data analysis and report preparation. b. The SMC monitoring program seeks to coordinate and leverage existing monitoring efforts to produce regional estimates of the condition of streams and rivers, improve data comparability and quality assurance, and maximize data availability, while conserving monitoring expenditures. The primary goal of this program is to implement an ongoing, large-scale regional monitoring program for southern California’s coastal streams and rivers. c. A comprehensive program was designed by the SMC, in which each participating group assesses its local watersheds and then contributes their portion to the overall regional assessment. Types of data being collected include water quality, physical habitat and riparian condition, and biological communities, including benthic invertebrates and algae. Sampling occurs in 17 coastal southern California watersheds between Ventura to the Tijuana Rivers. Sites are allocated each year based on current study design.

2. Southern California Bight Project
The Southern California Bight Project (SCBP) is an ongoing marine monitoring collaboration that was started in 2008 between the Southern California Coastal Water Research Project (SCCWRP) and nearly 100 participating organizations that examines how human activities have affected the health of 1,539 square miles of Southern California’s coastal waters. The objective is to investigate the condition of marine ecosystems across both time and space.

L. Special Studies
The special studies included in Part XI of the MRP are optional for all Permittees in Los Angeles and Ventura counties. It is encouraged that Permittees consider conducting these special studies. The results of these studies may support future Basin Plan amendments to revise TMDLs and/or water quality standards.

M. Reporting Requirement Objectives
Part XII of the MRP outlines objectives for the Order’s reporting requirements. These objectives are consistent with the previous MS4 permits.

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N. Standard Monitoring and Reporting Provisions
Part XIII of the MRP and Attachment D of the Order includes standard monitoring and reporting provisions. These provisions are consistent with the previous MS4 permits.

O. Reporting Requirements
All reporting requirements in Attachments D, E, H, and I, were carried over from the previous MS4 permits.

1. Program Reports
The Annual Report requirement was required in the previous 2012 Los Angeles County, 2014 City of Long Beach and 2010 Ventura County MS4 Permits, per federal regulations. The Reporting Forms provide summary information to the Los Angeles Water Board on each Permittee’s implementation of the minimum control measures (MCMs); participation in one or more Watershed Management Programs; the impact of each Permittee’s stormwater and non-stormwater discharges on the receiving water; each Permittee’s compliance with receiving water limitations and water quality based effluent limitations; and the effectiveness of each Permittee(s) control measures in reducing discharges of pollutants from the MS4 to receiving waters.

In addition, the Reporting Forms allow the Los Angeles Water Board to assess whether the quality of MS4 discharges and the health of receiving waters is improving, staying the same, or declining as a result of watershed management program efforts, and/or TMDL implementation measures, or other control measures and whether changes in water quality can be attributed to pollutant controls imposed on new development, re-development, or retrofit projects. The Reporting Forms provide Permittees a forum to discuss the effectiveness of its past and ongoing control measure efforts and to convey its plans for future control measures as well as a way to present data and conclusions in a transparent manner so as to allow review and understanding by the general public. Overall, the Reporting Forms allow Permittees to focus reporting efforts on watershed condition, water quality assessment, and an evaluation of the effectiveness of control measures.

Permittees must use the Reporting Forms contained in Attachment H of the Order (i.e., Annual Report Form and Watershed Management Program Progress Report Form). As attachments to the Annual Report Form, Permittees are also required to report on compliance with Trash TMDLs and Trash Discharge Prohibitions using the Trash TMDL Reporting Form and/or Trash Discharge Prohibition Reporting Form contained in Attachment I of the Order or a revised form approved by the Los Angeles Water Board. This option is included so that Permittees are not constrained to the reporting structure of the forms in Attachment I of the Order.

Regardless of the reporting format, Permittees are required to report on all the elements within Attachment H and I of the Order.

In the previous permits, Ventura County Permittees developed their own Annual Report form while Los Angeles County Permittees including the City of Long Beach initially used Attachment U-4 (Individual Annual Report Form) from the 2001 Los Angeles County MS4 Permit for reporting on permit implementation. For the 2015/2016 reporting year and onwards, the Los Angeles Water Board provided Los Angeles County Permittees including the City of Long Beach an Individual Form and a Watershed Form for annual reporting. Although the Watershed Form was to

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be filled out for Permittees participating in a Watershed Management Program, the Individual Form also contained overlapping questions that pertained to Permittees participating in a Watershed Management Program. To eliminate overlaps and simplify reporting, the Annual Report Forms provided by the Los Angeles Water Board have been revised for the Regional MS4 Permit. These forms still contain all of the elements in the previous forms, but questions have been refined to match the requirements of the Order. Additionally, Permittees participating in a Watershed Management Program will now report on the majority of their Watershed Management Program activities in a separate Watershed Management Program Progress Report form (see below).

The Program Reports shall be submitted electronically by the deadlines specified in Part XIV of the MRP. This is per 40 CFR Part 127 that requires Permittees to electronically report information. According to this requirement, Permittees are required to submit their reports through the Storm Water Multiple Application and Report Tracking System (SMARTS), which is compliant with U.S. EPA’s CrossMedia Electronic Reporting Rule (40 CFR Part 3). However, until SMARTS is able to accommodate and accept all Permittee submittals, Permittees are required to submit their Program Reports and semi-annual monitoring data to the Los Angeles Water Board electronically via CDs, DVDs, flash drives, email, etc.

2. Watershed Management Program Progress Report
The Watershed Management Program Progress Report Form, contained in Attachment H, serves as reporting requirements for Watershed Management Program implementation and shall be completed by each Watershed Management Program. The items in this report are directly based on Annual Report requirements included in the previous 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits and are refinements of reporting items contained in the previous Watershed Form used by Los Angeles County Permittees including the City of Long Beach.

Additionally, Part XIV.A.2 of Attachment E has been modified to include a requirement that each Permittee participating in a Watershed Management Program provide the Watershed Management Program Progress Report to the public, including through direct outreach and on its website or a website specifically dedicated for the Watershed Management Program group. This change was made to ensure greater accountability and transparency. The U.S. EPA similarly requires Permittees to post their progress reports on their websites (e.g., Washington, D.C.

MS4 NPDES Permit, NPDES Permit No. DC0000221).

3. Monitoring Report
Part XIV.B of the MRP requires Permittees to submit a Monitoring Report twice a year that includes monitoring results and certification. Moreover, Permittees are required to annually submit summary of sampling events, a summary of exceedances of receiving water limitations and WQBELs, QA/QC, and a summary of aquatic toxicity monitoring. The Monitoring Report includes monitoring-related reporting requirements contained in the previous 2012 Los Angeles County, 2014 City of Long Beach, and 2010 Ventura County MS4 Permits.

Permittees must submit monitoring results for sampling events per the schedule indicated in the MRP. This schedule is the same as the 2012 Los Angeles County

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and 2014 City of Long Beach MS4 Permits. The Order’s reporting schedules are a refinement of the due dates in these previous permits.

In the 2012 Los Angeles County and 2014 City of Long Beach MS4 Permits, receiving water and outfall monitoring results were required to be submitted to the Los Angeles Water Board semi-annually. However, these permits did not identify an actual date for submittal. During permit implementation, Los Angeles County Permittees were directed by the Los Angeles Water Board to submit monitoring results for sampling events for the period, January 1 to June 30, one hundred and sixty-eight (168) days later on December 15; and monitoring results for sampling events for the period, July 1 to December 31, one hundred and sixty-six (166) days later on June 15.

In the 2010 Ventura County MS4 Permit, Permittees were required to submit monitoring data electronically to the Los Angeles Water Board: (1) 90 days from the sample collection date for mass emissions, major outfalls, aquatic toxicity, and TMDL compliance monitoring; and (2) 30 days from the sample collection date for beach water quality monitoring.

The Monitoring Report in the MRP includes a summary of the sampling events that is consistent with the requirements in the previous 2012 Los Angeles County, 2014 City of Long Beach and 2010 Ventura County MS4 Permits. This information will allow the Permittees and the Los Angeles Water Board to evaluate the effects of differing storm events in terms of stormwater runoff volume and duration and instream effects.

4. Receiving Water Limitations Compliance Report
The Receiving Water Limitations Compliance Report was required in the previous Los Angeles County, City of Long Beach and Ventura County MS4 Permits within the Receiving Water Limitations Provisions and is being carried over to the Regional MS4 Permit. Permittees participating in a Watershed Management Program are exempt from the requirement to submit this report under the conditions specified in Part XIV.C.4 of the MRP.

P. TMDL Reporting
Part XV of the MRP includes TMDL reporting requirements in the Basin Plan similar to Part XIX in the MRP of the 2012 Los Angeles County and 2014 City of Long Beach Permits. Additionally, it includes clarifying provisions to address unique situations where a Permittee has no MS4 infrastructure or MS4 discharge to waterbodies addressed in a TMDL.

XIII. CALIFORNIA WATER CODE SECTION 13241
California Water Code section 13241 requires the Los Angeles Water Board to consider certain factors when establishing water quality objectives, including:
(a) Past, present, and probable future beneficial uses of water. (b) Environmental characteristics of the hydrographic unit under consideration, including the quality of water available thereto.
(c) Water quality conditions that could reasonably be achieved through the coordinated control of all factors which affect water quality in the area. (d) Economic considerations.

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(e) The need for developing housing within the region.
(f) The need to develop and use recycled water.

The Los Angeles Water Board is not establishing any water quality objectives in the Order.

However, California Water Code section 13263 requires the Board to take into consideration the provisions of section 13241 in prescribing waste discharge requirements, when such requirements are more stringent than what federal law requires.

In City of Burbank v. State Water Resources Control Board (2005) 35 Cal.4th 613, the California Supreme Court considered whether a regional water board must consider the provisions of section 13241 when issuing waste discharge requirements that serve as a NPDES permit by taking into account the costs a permittee will incur in complying with the permit requirements. The Court concluded that whether it is necessary to consider such cost information “depends on whether those restrictions meet or exceed the requirements of the federal Clean Water Act.” (Id. at p. 627.) The Court ruled that regional water boards may not consider the factors in section 13241, including economics, to justify imposing pollutant restriction that are less stringent than the applicable federal law requires. (Id. at pp. 618, 626- 627 [“[Water Code s]ection 13377 specifies that [] discharge permits issued by California’s regional boards must meet the federal standards set by federal law. In effect, section 13377 forbids a regional board's consideration of any economic hardship on the part of the permit holder if doing so would result in the dilution of the requirements set by Congress in the Clean Water Act…Because section 13263 cannot authorize what federal law forbids, it cannot authorize a regional board, when issuing a [] discharge permit, to use compliance costs to justify pollutant restrictions that do not comply with federal clean water standards”].) However, when the pollutant restrictions in an NPDES permit are more stringent than federal law requires, California Water Code section 13263 requires that the Water Boards consider the factors described in section 13241 as they apply to those specific restrictions.

The Los Angeles Water Board finds that each of the requirements in the Order are not more stringent than what federal law requires for the control of MS4 discharges of pollutants in the Los Angeles Region. The Board makes additional findings with respect to specific program areas throughout the Fact Sheet. Clean Water Act section 402(p)(3)(B) requires MS4 permits to include requirements to effectively prohibit non-stormwater discharges through the MS4 to receiving waters, as well as “controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants.” The permitting agency, be it the Los Angeles Water Board or U.S. EPA, must therefore include provisions when it finds it is appropriate to do so and to exercise its discretion to determine what permit conditions are necessary to control pollutants in a specific geographic area.

MS4 discharges in the Los Angeles Region are a continuing and significant source of pollutants to receiving waters, many of them impaired. As such, the Board finds that inclusion of all of the requirements in the Order are necessary and appropriate to control MS4 discharges in the Los Angeles Region including, but not limited to, requirements for nonstormwater discharges, technology and water quality-based effluent limitations, TMDLs, receiving water limitations, stormwater management program minimum control measures, and monitoring and reporting to ensure that the requirements of the Order are being met.

See Parts IV, V, VI, VII, IX, and XII, in particular. To the extent the requirements in the Order may be more specific or detailed than those enumerated in federal regulations under 40 CFR § 122.26 or in U.S. EPA guidance, the requirements have been designed to be consistent with and within the federal statutory mandates described in Clean Water Act section

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402(p)(3)(B) and the related federal regulations and guidance. Consistent with federal law, all the requirements in the Order could have been included in a permit adopted by U.S. EPA in the absence of California’s delegated authority to issue NPDES permits. (See Defs. of Wildlife v. Browner (9th Cir. 1999) 191 F.3d 1159, 1166.) Each of the requirements in the Order, especially when implemented together, constitute the critical means towards achieving the requirements and goals of the Clean Water Act. Therefore, since the Board determines that each of the requirements in the Order are not more stringent than what federal law requires, there is no legal requirement for the Board to consider the factors of California Water Code section 13241. The State Water Board recently confirmed this conclusion with respect to the 2012 Los Angeles County MS4 Order. (In the Matter of Review of Approval of Watershed Management Programs and an Enhanced Watershed Management Program Submitted Pursuant to Los Angeles Regional Water Quality Control Board Order R4-2012-0175, Order WQ 2020-0038, at p. 30, stating “[t]his requirement [to conduct a 13241 analysis], however, does not apply when the waste discharge requirements imposed by the regional board are not more stringent that required by federal law, as is the case here. (emphasis added) (footnotes omitted).)
349 The Regional MS4 Permit does not
contain any requirements that would result in a different conclusion here.

Further, the issue of whether numeric WQBELs are considered more stringent than what federal law requires, prompting a required consideration of the section 13241 factors, was the subject of recent litigation between the Board and some permittees, which was previously discussed in Part II.F. The Los Angeles Water Board disagrees that the inclusion of numeric WQBELs in the Order is more stringent than what federal law requires, as explained in Part V.B. This is supported by U.S. EPA in its guidance on incorporating TMDL WLAs for stormwater in NPDES permits, which explains that the permit’s administrative record needs to demonstrate that WQBELs will achieve the WLAs, whether the WQBEL is expressed numerically or as a BMP.350
Notwithstanding the above, the Los Angeles Water Board has nevertheless considered the factors set forth in California Water Code section 13241 in issuing the Order. The Board’s consideration of each of the factors is provided below. The Board has also considered all the evidence that has been presented to the Board regarding the section 13241 factors in issuing the Order. This includes specific costs of compliance information presented to the Board by Permittees and stakeholders, as well as specific cost information developed by the Board itself and that evidence is contained in the Administrative Record.

It is important to note that neither California Water Code section 13241 or section 13263 specifies the type or level of consideration required. Neither do these sections dictate what, if anything, a regional water board must do upon consideration of the factors. Several courts have interpreted the type of consideration required by California Water Code section 13241, primarily in the context of disputes over the “economic considerations” factor. In City of Arcadia et al. v. State Water Resources Control Board and Los Angeles Regional Water 349 In Order WQ 2020-0038, the State Water Board also found that the Los Angeles Water Board’s consideration of costs of compliance for the 2012 Los Angeles MS4 Permit went “well beyond what is required of them by law to assess the costs associated with their permits and assist municipalities in creating a manageable pathway to address water quality concerns.” (Order WQ 2020-0038 at p. 30.) 350 U.S. EPA, Memorandum, “Revisions to the November 22, 2002 Memorandum ‘Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for Storm Water Sources and NPDES Permit Requirements Based on Those WLAs,’” (Nov. 26, 2014), p. 6. See also, comment letter from U.S.

EPA Region IX on the draft Regional MS4 Permit, dated April 28, 2021, in which U.S. EPA states, “[n]either the Clean Water Act nor the 2014 TMDL Memorandum suggest that expressing WLAs as NELs is any more or less stringent than BMPs.”

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Quality Control Board (2006) 135 Cal.App.4th 1392 (“City of Arcadia I”), which involves a challenge to a trash TMDL, the Court of Appeal held that section 13241 does not specify a particular manner of compliance and thus the matter is within a regional water board’s discretion. (Id. at p. 1415.) Further, the court found that section 13241 does not define “economic considerations” and there is “no authority for the proposition that a consideration of economic factors under Water Code section 13241 must include an analysis of every conceivable compliance method or combinations thereof or the fiscal impacts on permittees.” (Id. at pp. 1415, 1417; State Water Board Order WQ 2020-0038 at p. 31.) In City of Arcadia et al v. State Water Resources Control Board and Los Angeles Regional Water Quality Control Board (2011) 191 Cal.App.4th 156 (“City of Arcadia II”), which involved a challenge to a triennial review of water quality standards,351 the Court of Appeal held that section 13241 “does not specify how a water board must go about considering the specified factors. Nor does it require the board to make specific findings on the factors.” (Id. at p. 177; see also California Association of Sanitation Agencies and City of Vacaville v. State Water Resources Control Board and Central Valley Regional Water Quality Control Board (2008) 208 Cal.App.4th 1438, 1464-1465 [in a challenge to certain water quality objectives, the Court of Appeal found that there was no support for the municipalities’ contention that each and every component part of the Water Quality Objectives must be tied to an economic analysis].) In City of Duarte v. State Water Resources Control Board (2021) 60 Cal.App.5th 258, 272 (“City of Duarte”), relying on prior case law, the Court of Appeal again affirmed that the “manner in which the Water Control Boards consider and comply with Water Code section 13241 is within their discretion.” It also held that “…the Water Control Boards are charged with taking into account economic considerations, not merely costs of compliance with a permit … economic considerations also include, among other things, the costs of not addressing the problems of contaminated water.” (Id. at p. 276.) Lastly, consideration of section 13241 does not require a “cost-benefit analysis.” (See State Water Board Order WQ 2020-0038 at p. 31.) In the 2001 Los Angeles County MS4 Permit litigation, the trial court held: “[w]here these statutes required ‘consideration’ of economics, the requirement is just that: a consideration.

Water Code section 13241 does not require a ‘cost-benefit analysis,’ as Petitioners suggest.

Economics is merely a factor to be considered.” (In re Los Angeles County Municipal Storm Water Permit Litigation (Super. Ct. Los Angeles County, 2005, No. BS 080548, Statement of Decision from Phase II Trial).) Further, in City of Duarte, the Court of Appeal held that the Los Angeles Water Board complied with Water Code section 13241 “as a matter of law” when adopting the 2012 Los Angeles County MS4 permit notwithstanding the absence of a cost-benefit analysis. (City of Duarte, supra, 60 Cal.App.5th at pp. 274-275.) The above case law demonstrates that the Los Angeles Water Board has broad discretion in how it considers the section 13241 factors.

Having considered the factors in California Water Code section 13241, the Los Angeles Water Board finds that the requirements in the Order are necessary to ensure the reasonable protection of beneficial uses of waterbodies in the Los Angeles Region and the prevention of nuisance. None of the factors of section 13241, including costs of compliance, is sufficient to justify failing to protect those beneficial uses. Nor is it sufficient to justify omitting any requirement in the Order, as the Board finds that doing so would unreasonably affect the designated beneficial uses of the region’s waters. Additionally, it would be wholly inconsistent with federal requirements to not include the requirements in the Order as the Board has deemed them necessary for the control of MS4 discharges in the Los Angeles Region. Where appropriate, the Board has provided Permittees with additional time to implement control measures to achieve final WQBELs and/or receiving water limitations. In addition, the Board 351 33 U.S.C. §1313(c)(1).

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has provided significant flexibility for Permittees to choose how to implement the requirements of the Order, including by working with other Permittees to implement costeffective control measures. The Order allows Permittees the flexibility to address critical water quality priorities, namely discharges to waters subject to TMDLs, but aims to do so in a focused and cost-effective manner while maintaining the level of water quality protection mandated by the Clean Water Act.

A. Past, Present, and Probable Future Beneficial Uses of Water Chapter 2 of the Basin Plan identifies designated beneficial uses for surface water bodies in the Los Angeles Region, which are the receiving waters for MS4 discharges.

The Basin Plan identifies whether the beneficial use is existing (i.e., attained on or after November 28, 1975 per 40 CFR section 131.3(e) or a potential beneficial use. Beneficial uses are designated as a potential beneficial use for several reasons, including implementation of the State Water Board’s policy entitled “Sources of Drinking Water Policy” (State Water Board Resolution No. 88-63); plans to put the water to such future use; potential to put the water to such future use; designation of a use by the Los Angeles Water Board as a regional water quality goal; or public desire to put the water to such future use.

The beneficial uses identified in the Basin Plan for the Los Angeles Region include water contact and non-contact recreation (REC-1 and REC-2), commercial and sport fishing (e.g., COMM), various types of aquatic life and wildlife habitats (e.g., WARM, COLD, WILD), groundwater recharge (GWR), drinking water supply (MUN), agricultural water supply (AGR), various types of industrial water supply (IND, PROC, POW), and navigation (NAV).352 The Ocean Plan also identifies designated beneficial uses for ocean waters of the State that must be protected, including industrial water supply, water contact and non-contact recreation, including aesthetic enjoyment, navigation, commercial and sport fishing, mariculture, preservation and enhancement of designated Areas of Special Biological Significance (ASBS), rare and endangered species, marine habitat, fish migration, fish spawning and shellfish harvesting. The Los Angeles Region has several ASBS, one of which is within the area covered by the Regional MS4 Permit.

This ASBS extends from Latigo Point in Los Angeles County to Mugu Lagoon in Ventura County.353
Beneficial uses of inland surface waters in the region generally include water contact recreation (REC-1) and WARM, COLD and/or COMM, reflecting the “swimmable/fishable” goal of section 101(a)(2) of the federal Clean Water Act. In addition, inland waters are usually designated as IND, PROC, REC-2, and WILD, and are sometimes designated as waters “that support habitats necessary, at least in part for the survival and successful maintenance of plant or animal species established under state or federal law as rare, threatened, or endangered” (RARE).354 Furthermore, many regional streams are primary sources of replenishment for major groundwater basins that supply water for drinking and other uses, and as such must be protected as waters used for recharge of groundwater (GWR). Beneficial uses of coastal waters in the Los Angeles Region, including bays, estuaries, lagoons, harbors, beaches, and the Pacific Ocean, include habitat for marine life and recreation, boating, shipping, and commercial and sport fishing. Beneficial uses of wetlands include many of the same uses designated for the rivers, lakes, and coastal water to which they are connected. 352 Definitions of beneficial uses are contained in Chapter 2 of the Basin Plan. 353 Basin Plan, pp. 5-4 to 5-7.
354 Ibid.

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In the 1990s, the Los Angeles Water Board contracted with California State University to survey and research beneficial uses of all waterbodies throughout the region and relied on these studies in the 1994 update to the Basin Plan. In 2014, the Los Angeles Water Board re-evaluated the current recreational beneficial use designations of the engineered channels in the Los Angeles River Watershed and resolved to retain the current recreational beneficial use designations (Resolution No. R14-011). Beneficial uses of the region’s waterbodies are also described by others in documents including, but not limited to, the Los Angeles River Revitalization Master Plan, Lower LA River Revitalization Plan, Los Angeles River Master Plan, the Ballona Creek Trail and Bikeway Environmental and Recreational Enhancement Study, and the Matilija Dam Ecosystem Feasibility Study Final Report.

Beneficial uses of waters impacted by MS4 discharges covered by the Order are also discussed in Part II.A “Description of Receiving Waters and Watershed Management Areas” and Part II.B “Geographic Coverage and Watershed Management Areas” of this Fact Sheet.

As discussed in Part II.C and Part II.D, MS4 discharges of stormwater and nonstormwater convey myriad pollutants to surface waters in every watershed of the region, including bacteria, trash, metals, organic compounds (including various pesticides), and nutrients, among others. These pollutants have damaging effects on both human health and aquatic and riparian ecosystems. Water quality assessments conducted by the Los Angeles Water Board have identified impairment of beneficial uses of water bodies in the Los Angeles Region caused or contributed by these pollutants in MS4 discharges.

As a result of these impairments, there are beach postings, fish consumption advisories, ecosystem and recreational impacts from trash and debris, and toxic conditions for aquatic life, among others. Forty-five TMDLs established by the Los Angeles Water Board and U.S. EPA identify MS4 discharges as one of the pollutant sources causing or contributing to impairments of beneficial uses. The requirements of the Order are necessary to protect and restore the past, present, and probable future beneficial uses of surface waters in the region.

B. Environmental Characteristics of the Hydrographic Unit Under Consideration, Including the Quality of Water Available Thereto
Environmental characteristics of each of the Watershed Management Areas (WMAs) covered by the Order, including the quality of water, is discussed in Part II.A and Part II.B of this Fact Sheet. Additional information can be found in the Los Angeles Region’s Watershed Management Initiative Chapter and the State’s Clean Water Act Section 303(d) List of impaired waters.

Watershed Management Initiative Chapter:
http://www.waterboards.ca.gov/losangeles/water_issues/programs/regional_program/ watershed/index.shtml
Clean Water Act Section 303(d) List of impaired waters:
https://www.waterboards.ca.gov/water_issues/programs/tmdl/integrated2014_2016.sh tml
The quality of water in receiving waters as impacted by MS4 discharges has been routinely monitored by Permittees through the Monitoring and Reporting Programs under all three previous permits (Order No. R4-2010-0108, Order No. R4-2012-0175, and Order No. R4-2014-0024). An analysis of the monitoring data collected under the

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three previous permits is provided in Part II.E of this Fact Sheet and in the MS4 Monitoring Data Review Report (July 2020 [Section 3]; November 2020 [Sections 8-11]) as well as in a series of three presentations to the Board at regularly scheduled Board meetings on May 18, 2018, July 12, 2018, and September 13, 2018.

C. Water Quality Conditions that Could Reasonably be Achieved Through the Coordinated Control of All Factors Which Affect Water Quality in the Area Subsection (c) of section 13241 provides for the consideration of “[w]ater quality conditions that could reasonably be achieved through the coordinated control of all factors which affect water quality in the area.” As with the other factors in 13241, there is no formal guidance or interpretation on how this factor is to be specifically considered, especially in the context of issuing a permit for a particular type of discharge under Water Code section 13263. In the context of establishing water quality objectives, it is necessary to consider all factors that affect water quality, including an analysis of all sources of the applicable pollutant. However, this factor does not lend itself to being reconsidered later when issuing waste discharge requirements as water quality objectives have already been established and the focus during the permitting stage is regulating a particular type of discharge or a discharge from a specific source, and not all possible sources of pollutants to a receiving water. The water quality objectives implemented by the Order have already been established in the Basin Plan and other water quality control plans through a separate regulatory process, and those water quality objectives were deemed reasonable and achievable when they were promulgated in order to protect beneficial uses.

Some permittees have previously interpreted this factor as requiring the Los Angeles Water Board to determine that water quality conditions or specific permit requirements are “reasonably achievable” and that such a determination includes a consideration of economics or costs of compliance as part of the “reasonably be achieved” language in section 13241(c). No support has been provided to the Board for this interpretation. It is important to note for this analysis that this factor in section 13241(c) does not include a consideration of economics or costs of compliance. The Board interprets this factor as requiring a consideration of the water quality conditions that could reasonably be achieved by the Order from a technical or scientific standpoint only. A consideration of economics, including the costs of compliance, in this factor would be completely superfluous to the wholly separate consideration in section 13241(d) – “economic considerations” – which is discussed in Part XIII.D, below.

When it comes to the permitting stage, the Los Angeles Water Board is required to implement any relevant water quality control plans, including water quality objectives, in its permits. (Water Code § 13263(a).) In so doing, the Board “shall” (among other things) “take into consideration the beneficial uses to be protected, the water quality objectives reasonably required for that purpose,” “other waste discharges,” (id.), “together with any more stringent effluent standards or limitations necessary to implement water quality control plans, or for the protection of beneficial uses.” (Water Code § 13377.) The Board has previously established numerous TMDLs as part of its Basin Plan, including state programs of implementation and schedules for achievement of water quality objectives.

In addition, USEPA has established several TMDLs for waters in the Los Angeles Region. USEPA established these TMDLs for the protection of beneficial uses. In addition, for several USEPA-established TMDLs, the Los Angeles Water Board has established state programs of implementation and schedules as part of its Basin Plan.

The Los Angeles Water Board must therefore also include WQBELs in the permit to

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implement the TMDLs and the WLAs established therein to achieve water quality objectives.

Through the prior establishment of the water quality objectives and TMDLs, the Board has found that such water quality conditions can reasonably be achieved, in many cases over time in accordance with implementation schedules, through the coordinated control of all factors which affect water quality in the area. To be sure, implementation of the TMDLs and associated WLAs are expected to reasonably achieve the water quality objectives in the Basin Plan and other water quality control plans if they are applied not only to MS4 discharges, but also to other discharges contributing to water quality impairment, such as industrial discharges and discharges from POTWs (see for example, the Los Angeles River Metals TMDL, which assigns a large portion of the responsibility for pollutant reductions to POTWs, and the Calleguas Creek Organochlorine Pesticides and PCBs TMDL, which assigns a large portion to agricultural dischargers). That said, permitting and regulation of MS4 discharges are a key component of achieving the water quality objectives in the Basin Plan and other water quality control plans. As noted in various places throughout this Fact Sheet, one of the key factors necessary to achieve the water quality objectives in the Los Angeles Region is proper control of MS4 discharges. Indeed, “urban runoff is causing and contributing to impacts on receiving waters throughout the state and impairing their beneficial uses.” (State Water Board Order WQ 2001-15, p. 7; State Water Board Order WQ 2015-0175, p. 15.) Accordingly, and as explained in further detail below, the Los Angeles Water Board finds that the conditions contained in this permit, including numeric WQBELs, are key to ensuring reasonable achievement of water quality objectives in the Los Angeles Region.

Coordinated Control of all Factors Affecting Water Quality The Los Angeles Water Board and State Water Board regulate water quality in the Los Angeles Region through various permitting actions. The different types of surface water discharges that the Water Boards regulate include point sources such as POTWs, industrial facilities, dewatering activities, groundwater cleanup activities, and MS4 discharges of stormwater and non-stormwater; and nonpoint sources such as agricultural discharges and littering. These discharges are regulated through NPDES permits, waste discharge requirements, waivers of waste discharge requirements, and memorandums of understanding in accordance with State and federal law, regulation, and policy. These various permits and other regulatory mechanisms contain provisions and requirements to achieve water quality objectives and TMDLs, ranging from compliance with pollution prevention plans to compliance with effluent limitations. The regulatory mechanisms are issued as part of a watershed management approach, often according to a TMDL program of implementation, to ensure coordinated implementation by all sources at the watershed scale to attain water quality objectives. TMDLs in particular consider all the likely means of compliance, including a mix of treatment strategies and control measures to be implemented by all sources, which are reflected in the monitoring requirements, implementation schedules, and direction for incorporation of pollutant wasteload and load allocations into permits.

With respect to stormwater specifically, the Los Angeles Water Board and State Water Board regulate many types of stormwater discharges, including those of municipalities,

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universities and other non-traditional Phase II discharges355, industrial sites356, construction sites357, and state agencies like Caltrans.358 The Phase II MS4 Permit effectively prohibits non-stormwater discharges and contains effluent and receiving water limitations. The Phase II MS4 Permit specifies the actions necessary to reduce the discharge of pollutants in stormwater to the MEP and comply with TMDLs, including participation in the watershed management programs of Phase I MS4 permittees359 or alternative plan to demonstrate reasonable assurance of compliance with WLAs. The Industrial General Permit contains non-stormwater prohibitions, effluent limitations expressed as numeric action levels and, TMDL requirements, including numeric effluent limitations, and receiving water limitations.360 The Construction General Permit contains non-stormwater prohibitions, effluent limitations expressed as numeric action levels, TMDL requirements, and receiving water limitations.361 The Caltrans MS4 Permit effectively prohibits non-stormwater discharges and contains effluent and receiving water limitations, and categorical pollutant requirements to attain TMDLs within 20 years.362
The Permittees subject to the Order are not solely responsible for ensuring that water quality objectives in the receiving waters are met; rather, achieving and maintaining water quality objectives is a coordinated effort and all regulated dischargers must contribute. That said, as previously noted in Part II.E of this Fact Sheet, MS4 discharges are a significant source of pollutants to receiving waters and their regulation plays an important role in the achievement of water quality objectives. To not regulate discharges from MS4s -- from the Permittees subject to the Order in particular -- would place an undue burden on other types of discharges, especially since, as discussed in Part II.E of this Fact Sheet, MS4 discharges constitute a leading cause of water quality impairment in the Los Angeles Region.

Water Quality Objectives as Incorporated into the Order are Reasonably Achievable
When considering the achievability of water quality objectives from the singular perspective of the Order requirements, the application of the established water quality objectives to the Permittees’ MS4 discharges is reasonably achievable.

Permittees can and do coordinate several factors that affect water quality under their jurisdiction. Generally, improvements in the quality of receiving waters impacted by MS4 discharges can be achieved by reducing the volume of stormwater or non-stormwater discharged into the MS4 to receiving waters; reducing pollutant loads to stormwater and 355 State Water Board, Order No. 2013-0001-DWQ (as amended by Orders WQ 2015-0133-EXEC, ORDER WQ 2016-0069-EXEC, WQ ORDER 2017-XXXX-DWQ, ORDER WQ 2018-0001-EXEC, AND ORDER WQ 2018-0007-EXEC), NPDES Permit for Stormwater Discharges from Small MS4s. 356 State Water Board, Order No. 2014-0057-DWQ, NPDES General Permit for Stormwater Discharges Associated with Industrial Activities (as amended by Order No. 2015-0122-DWQ). 357 State Water Board, Order 2009-0009-DWQ (as amended by 2010-0014-DWQ and 2012-0006-DWQ), NPDES General Permit for Stormwater Discharges Associated with Construction and Land Disturbance Activities.
358 State Water Board, Order 2012-0011-DWQ (as amended by Orders WQ 2014-0006-EXEC, WQ 2014- 0077-DWQ, and WQ 2015-0036-EXEC), NPDES Statewide Storm Water Permit for State of California Department of Transportation.
359 Ibid. Attachment G, pages 37-55.
360 Ibid. Page 21 and Attachment E.
361 Ibid. Page 28-31.
362 Ibid. Page 31.

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non-stormwater through source control/pollution prevention, including operational source control such as street sweeping and public education, controlling illicit connections and illicit discharges, and conducting inspections of industrial and commercial facilities; and removing pollutants that have been loaded into stormwater or non-stormwater before they enter receiving waters, through infiltration, treatment, or diversion to a sanitary sewer.

The Order is designed to reduce pollutants to waterbodies from MS4 discharges through the implementation of multi-faceted stormwater management programs at the municipal and watershed levels. Overall improvements in MS4 discharge quality are expected to occur over time with ongoing implementation of the requirements in the Order.

Information obtained through the robust monitoring programs implemented through the previous permits; implementation of stormwater management measures by individual municipalities within a watershed since the issuance of the first MS4 permits in the Los Angeles Region; analysis during TMDL establishment, including source analysis, loading capacity analysis and linkage analysis; and available predictions from the RAAs of many Watershed Management Programs clearly demonstrate that water quality objectives can be reasonably achieved over time through the coordinated control of all factors that affect MS4 discharge impacts on receiving waters.

Since the issuance of the previous MS4 permits, municipalities both locally and nationally have gained considerable experience in the management of municipal stormwater and non-stormwater discharges. The technical capacity to monitor stormwater and its impacts on water quality has also increased. In many areas, monitoring of the impacts of stormwater on water quality has become more sophisticated and widespread. Better information on the effectiveness of stormwater controls to reduce pollutant loadings and address water quality impairments is now available. The International Stormwater BMP Database (http://www.bmpdatabase.org/) provides extensive information of the performance capabilities of stormwater controls and continues to be updated with new studies. Locally, the Southern California Stormwater Monitoring Coalition’s California LID Evaluation and Analysis Network (SMC CLEAN) has developed a standard protocol for monitoring of BMPs363 and a guidance document for constructing, maintaining, and monitoring BMPs.364 The Southern California Coastal Water Research Project (SCCWRP) has analyzed BMP treatment effectiveness using monitoring data specifically from BMPs implemented in California365 and has made their findings readily available to Permittees and regulatory agencies through a web application.366
In fact, some of the many advances in how to effectively control stormwater and pollutants in stormwater have occurred locally within the Los Angeles Region and include the development of cost effective trash full capture devices; stormwater diversion, treatment and beneficial use facilities such as the Santa Monica Urban Runoff Recycling Facility (SMURRF) and Carriage Crest Park; stormwater capture, storage, and reuse facilities such as in Sun Valley; low impact development/site design practices; 363 SMC CLEAN. LID/GI Monitoring Protocol (August 1, 2017) 364 SMC CLEAN. Low Impact Development & Green Stormwater Infrastructure Construction, Inspection, Maintenance, and Monitoring Guidance Manual (May 2019)
365 Afrooz, N., M. Beck, T. Hale, L. McKee, K.C. Schiff. 2019. BMP Performance Monitoring Data Compilation to Support Reasonable Assurance Analysis. Technical Report 1081. Southern California Coastal Water Research Project. Costa Mesa, CA.
366 SCCWRP. California BMP effective calculator (v1.2.0). https://sccwrp.shinyapps.io/bmp_eval/ (accessed September 3, 2019)

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and innovative/opportunistic culvert inlet multi-media filters. There are many other case studies of municipalities that have implemented innovative and effective stormwater management measures, many of which have been demonstrated through the implementation of Watershed Management Programs by Permittees in Los Angeles County.

In addition to the advances in monitoring and individual stormwater treatment technologies, there have been advances in watershed-wide planning and implementation of stormwater treatment technologies through state-of-the-art computer modeling. Historically, some have argued that while BMPs may be effective at treating stormwater on a small scale, their effectiveness at treating stormwater on a watershed scale is less certain. However, in recent years, there have been significant advances in the planning and design of watershed wide BMPs to achieve WQBELs and receiving water limitations. These advances are demonstrated by the 11 WMPs and 12 EWMPs submitted by groups of Permittees in compliance with the 2012 Los Angeles County and 2014 Long Beach MS4 Permits. Many of the WMPs and EWMPs were based on the Watershed Management Modeling System (WMMS) developed by Los Angeles County367 in 2010. WMMS is a comprehensive planning tool based on computer models that can simulate hydrologic and pollutant transport processes for all the major watersheds within Los Angeles County. WMMS further predicts the pollutant load reductions that can be achieved by the implementation of various stormwater treatment control technologies throughout the watersheds. This modeling system combines a watershed runoff and receiving water quality model (Loading Simulation Program in C++ (LSPC)) with a BMP performance model (System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN)) to determine the most cost-effective combination of stormwater management measures to achieve desired water quality outcomes. Los Angeles County updated WMMS in 2020 (WMMS 2.0) based on more recent input and water quality calibration data to further refine and improve its predictive capabilities.368 Eight of the WMPs and 12 EWMPs all used WMMS or similar cutting edge modeling systems as part of their RAAs to characterize their current pollutant loading, determine the required reductions to meet WQBELs and receiving water limitations, and prescribe the number, location, and design specifications for BMPs that could meet their required load reductions to achieve water quality objectives within prescribed timeframes. These RAAs prove that the Permittees’ MS4 discharges can reasonably achieve the required water quality conditions, either immediately or over time.

The Water Quality Objectives Incorporated in the Order Consider Local Conditions and Provide Flexibility in Implementation
The Order contains requirements based on water quality objectives and TMDLs, which, where appropriate, incorporate information regarding local conditions and flexibility such that they can reasonably be achieved by Permittees. The following paragraphs give examples of how local conditions are already incorporated into receiving water limitations and water quality-based effluent limitations for bacteria and metals, two of the most pervasive categories of pollutants found in MS4 discharges. 367 Los Angeles County Flood Control District and Los Angeles County Department of Public Works. 2020b. Watershed Management Modeling System Version 2.0 Phase II Report: BMP Model and Optimization Framework. Los Angeles County Department of Public Works, Stormwater Quality Division. 368 Ibid.

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Bacteria
Bacteria TMDLs in the Los Angeles Region implement single sample water contact recreation bacteria water quality objectives by using a reference system/antidegradation approach. This approach ensures that “bacteriological water quality is at least as good as that of a [local] reference system and that no degradation of existing bacteriological water quality is permitted where existing bacteriological water quality is better than that of the selected reference system.”369 As a result of this approach, the Order’s bacteria receiving water limitations are expressed in the form of annual allowable exceedance days, which allow Permittees to exceed bacterial water quality objectives in receiving waters at the same frequency as a local reference water body. This approach takes into consideration natural sources of bacteria, which may cause or contribute to exceedance of the single sample water quality objectives.370 Additionally, engineered channels are subject to an exception called the high flow suspension, which suspends bacterial water quality objectives associated with REC-1 (water contact recreation) and REC-2 (non-contact water recreation) beneficial uses during days with rainfall greater than or equal to 0.5 inch and the 24 hours following the rain event. Receiving waters that are engineered channels in which this suspension applies include portions of Ballona Creek, Dominguez Channel, Los Angeles River, and San Gabriel River.371 This exception, which is implicitly incorporated into the Order’s receiving water limitations, is also included in the Order’s compliance determination provisions (Part X.A.3) for clarity.

Furthermore, in the Ballona Creek watershed specifically, the Los Angeles Water Board removed the REC-1 use in Ballona Creek Reach 1 and revised the REC-1 use in Ballona Creek Reach 2 to Limited REC-1 based on the results of a Use Attainability Analysis. The analysis was conducted between March and August of 2002 to determine actual and potential recreational uses of the creek in conformance with 40 CFR § 131.10(g). The result of the remaining REC-2 use designation in Reach 1 and the new Limited REC-1 use designation in Reach 2 are higher single sample geometric mean limits for the bacteria water quality objectives to protect those uses.

Metals
Metals receiving water limitations and WQBELs are derived from 40 CFR section 131.38 (also known as the California Toxics Rule or CTR). The CTR specifies water quality objectives for metals as a function of water-effect ratios (WERs) which, by default, have a value of 1.0. The Los Angeles Water Board has approved several site-specific WERs in the Los Angeles River and Calleguas Creek watersheds, ranging in values from 1.32 to 9.69, that account for local water quality conditions that may influence the bioavailability and/or toxicity of metals. These site-specific WERs, all being greater than 1.0, have adjusted receiving water limitations and WQBELs, including those for MS4 discharges, to more accurately reflect the toxicity of metals to aquatic life in these receiving waters. 369 Basin Plan Chapter 3
370 Tiefenthaler, L.L., E.D. Stein, G.S. Lyon. 2008. Fecal Indicator Bacteria (FIB) levels during dry weather from southern California reference streams. Technical Report 542. Southern California Coastal Water Research Project. Costa Mesa, CA.
371 Basin Plan Table 2-1a

EXHIBIT A
Tuesday, October 07, 2025 Reg CC MTG, Page *684
MS4 DISCHARGES WITHIN THE ORDER NO. R4-2021-0105
LOS ANGELES REGION NPDES NO. CAS004004
ATTACHMENT F – FACT SHEET F-319
Similarly, the Los Angeles Water Board adopted site specific water quality objectives for lead based on the results of a Permittee-led special study. The study recalculated the acute and chronic lead objectives for portions of the Los Angeles River using an expanded nation-wide dataset provided by USEPA following USEPA procedures. The Los Angeles Water Board revised the existing Los Angeles River Metals TMDL to update the numeric targets and WLAs, including those for MS4 discharges, based on the recalculated lead objectives. The resulting numeric targets and WLAs for lead were greater than those in the original TMDL.

Additionally, several metals TMDLs considered and, where appropriate, used sitespecific metals translators. These translators represent the fraction of total recoverable metals in a receiving water that is in the dissolved form. Site-specific metals translators were used to calculate the metals waste load allocations in the metals TMDLs for Ballona Creek, Los Angeles River, Los Cerritos Channel, and San Gabriel River. These waste load allocations are incorporated into the Order as water quality-based effluent limitations.

Conclusion
Based on a consideration of all factors controlling water quality in the region, including the multiple types of discharges regulated by the Los Angeles Water Board and State Water Board, the multiple types of stormwater-specific discharges regulated by the Los Angeles Water Board and the State Water Board, the multiple actions that Permittees can take to reduce pollutants in their discharges, and the effectiveness of these actions as demonstrated by monitoring and the RAAs in existing watershed management programs, the Los Angeles Water Board finds that water quality conditions based on the requirements of this Order to implement water quality objectives can reasonably be achieved, even if such conditions are achieved over time (see Table F-26). The water quality objectives themselves have already been established and found to be reasonably achievable. In many cases, the Los Angeles Water Board has considered special studies and site-specific information to ensure that the water quality objectives are no more stringent than necessary to protect beneficial uses without degradation of water quality. The requirements of the Order based on these water quality objectives, including numeric WQBELs to implement TMDL WLAs, are reasonably achievable.