PUBLIC STORM DRAIN STANDARDS
Adopted by the Santa Rosa City Council
Resolution No. XXXXX
Date: XXXXX
Attachment 1
SD STANDARDS CHANGE TYPE COLOR KEY
GOVERNMENT REGULATIONS #3B9B4B
OPERATIONS AND MAINTENANCE #A50026
CLARITY #FD8366
INDUSTRY #364B9A
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TABLE OF CONTENTS
I. PUBLIC STORM DRAIN DESIGN STANDARDS .......................................................... 1
1. CONNECTION TO THE EXISTING STORM DRAIN SYSTEM .................................... 8
2. MATERIALS ....................................................................................................................... 9
3. SIZE ................................................................................................................................... 11
4. ALIGNMENT .................................................................................................................... 11
5. SLOPE ............................................................................................................................... 12
6. COVER .............................................................................................................................. 14
7. MANHOLES AND OTHER STRUCTURES ................................................................... 14
8. STORM DRAIN INLETS ................................................................................................. 15
9. STUB CAPS ...................................................................................................................... 17
10. VIDEO INSPECTION ....................................................................................................... 17
11. ABANDONMENT OF STORM DRAIN PIPES .............................................................. 17
12. EASEMENTS .................................................................................................................... 17
13. ACCESS ROADS .............................................................................................................. 18
14. .MAINTENANCE ............................................................................................................. 19
15. WATER QUALITY........................................................................................................... 19
16. OTHER REQUIREMENTS .............................................................................................. 20 II. PUBLIC STORM DRAIN STANDARD DETAILS ........................................................ 22 III. PUBLIC STORM DRAIN CONSTRUCTION STANDARD SPECIFICATIONS ......... 48 IV. LIST OF APPROVED ITEMS FOR CONSTRUCTION ................................................. 59
APPENDIX A: FLOOD AND DRAINAGE REVIEW PLAN SUBMITTAL CHECKLIST
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I. PUBLIC STORM DRAIN DESIGN STANDARDS
QUICK REFERENCE SHEETS
DESIGN REQUIREMENTS
Minimum pipe
diameter: 15 inches
Pipe materials:
Reinforced concrete pipe (RCP), high-density polyethylene (HDPE) pipe, and high-performance polypropylene (HPPP) pipe that conforms to these specifications. HDPE and HPPP shall not be accepted for publicly owned utilities in Wildland-Urban Interface (WUI) Fire Areas as defined by the current City of Santa Rosa (City) WUI map and other restricted use defined herein.
Horizontal
separation from
sewer lines:
Five (5) feet clear (outer walls) except at crossings or as required by the current City of Santa Rosa’s Sanitary Sewer System Design and Construction Standards
Horizontal
separation from
water lines and
other utilities:
Four (4) feet clear (outer walls) minimum except at crossings or as required by the current City of Santa Rosa’s Water Distribution Design and Construction Standards
Vertical curves: Not allowed
Horizontal Curves:
RCP: 300 feet minimum radius (allowed at catch basins and when pipeline is installed under the pavement parallel to the concrete gutter).
See detailed design standards.
HDPE, HPPP: 3° mitered couplings with no joint or pipe deflection, or as specified in the manufacturer’s specifications, and a maximum of one mitered coupling per 10-foot length of pipe. Radius shall not be less than 300 feet. See Design Requirements.
Pipe slope: ≤15%
Minimum cover: 12 inches for class III RCP and HDPE (outside of pipe to road subgrade) and as outlined in Table I-1 and Section 6 herein.
Maximum distance
between structures: 300 feet
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Minimum pipe
velocity and slope:
Minimum three (3.0) feet per second at half-full flow for closed conduit systems as detailed in these standards
Minimum two and a half (2.5) feet per second at the design flow for earth channels, ditches, and hardened or concrete-lined channels for City-owned and operated channels
For Sonoma Water-owned and operated channels, refer to the current Sonoma Water’s Flood Management Design Manual.
Time of
Concentration
Minimums
5 minutes – Urban, commercial, industrial, and residential with more than eight (8) units per acre
10 minutes – Residential 2-8 units per acre
15 minutes – Residential less than two (2) units per acre, undeveloped open space
Rainfall intensities
National Oceanic and Atmospheric Administration’s (NOAA) Atlas 14 and NOAA’s National Weather Service's Atlas 14 Precipitation Frequency Data Server, or current versions
Note: New development, redevelopment, and capital improvement projects may be required to implement stormwater quality source and treatment controls commonly referred to as either post construction Best Management Practices (BMPs) or Low Impact Development (LID) features.
Refer to the current regional Storm Water Low Impact Development Technical Design Manual to determine if the project requires permanent stormwater BMPs and for design criteria.
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ACRONYMS AND ABBREVIATIONS
AASHTO American Association of State Highway and Transportation Officials ASTM American Society of Testing and Materials
BMPs Best Management Practices
City City of Santa Rosa
FHWA U.S Department of Transportation Federal Highway Administration FMDM Sonoma Water’s Flood Management Design Manual dated March 2020, or current version
HDPE Annular high-density polyethylene
HEC Hydraulic Engineering Circular
HPPP high-performance polypropylene
LID Stormwater Low Impact Development
LID Manual City of Santa Rosa, et. al. Regional Storm Water Low Impact Development Technical Design Manual dated May 2017 (Revised December 2020), or current version
MS4 Permit Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer Systems, current version or as grandfathered in under previous versions of the MS4 permit as allowed by current MS4 permit conditions
MSMVCD Marin/Sonoma Mosquito and Vector Control District NOAA National Oceanic and Atmospheric Administration
NPDES National Pollutant Discharge Elimination System
O&M Plan Operation and maintenance plan
RCP Reinforced concrete pipe
SD Standards City of Santa Rosa’s Public Storm Drain Standards SWLIDS Storm Water Low Impact Development Submittal Report TPW Transportation and Public Works Department
WUI Wildland-Urban Interface
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PUBLIC STORM DRAIN DESIGN STANDARDS
PURPOSE:
The purpose of this document is to provide standards for the design of public storm drain system improvements in the City of Santa Rosa (City). All storm drainage systems must be designed per the standards herein and the most current version of Sonoma Water’s Flood Management Design Manual (FMDM). These City Public Storm Drain Standards (SD Standards) precede the FDMD for City-owned and maintained storm drain infrastructure.
Developers and design engineers should be aware that stormwater treatment, volume capture, and hydromodification requirements, as specified in the City’s current National Pollutant Discharge Elimination System (NPDES) Permit and Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer Systems permit (MS4 Permit), may apply.
Applicability, requirements, and design criteria are governed by the current version of the regional Storm Water Low Impact Development (LID) Technical Design Manual (LID Manual) and other applicable guidance documents.
These standards do not include, but may reference, additional requirements established by other departments of the City and other government agencies. These standards are intended to impose minimum acceptable design criteria. The City Engineer may impose more or less stringent requirements based on specific project conditions. Developers and their design engineers are responsible for complying with these standards and all other requirements for the design of storm drain facilities within the City. Design engineers are responsible for initiating written requests for approval (variance request) of any design concept that differs from these standards, verifying additional requirements set forth by other departments of the City or other government agencies, performing any necessary calculations or studies, and resolving any problems with the appropriate department or agency. Developers and design engineers should be aware that Section 402(p) of the federal Clean Water Act establishes requirements for National Pollutant Discharge Elimination System permits for industrial and construction-related stormwater discharges.
POLICY:
The City’s policy is to safely collect and convey stormwater to the nearest public flood control facility in a storm drain system approved by the City of Santa Rosa’s Transportation and Public Works Department (TPW) and Water Department while conforming to water quality and volume capture (hydromodification) objectives and requirements.
DETENTION BASINS:
The following section on detention basins is not included in the FMDM. The FMDM outlines two risk-related design criteria for general detention facilities, including emergency outflow structures and high-flow conveyance routes, which shall be adhered to. These provisions shall be superseded if, at any point, additional and detailed detention design criteria are added to the FMDM. Design of detention facilities must also meet applicable criteria set forth by Marin/Sonoma Mosquito and Vector Control District requirements (MSMVCD). MSMVCD
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requirements are based on California State Health and Safety Code Division 3, Chapter 1, Article 5, Section 2060 et al. (State Health and Safety Code). Therefore, it is not within the City’s or City Engineer’s purview to grant variances from the MSMVCD requirements.
Detention basins are natural or constructed basins, oversized pipes, or underground vaults that attenuate stormwater runoff to reduce downstream peak flows for flood control purposes, to enhance water quality, or to alleviate hydromodification impacts. Detention basins to be owned and maintained by the City as public infrastructure due to existing storm drain infrastructure capacity issues are allowed as an alternative to requiring upsizing of the existing storm drain infrastructure, beginning at the downstream outfall and progressing upstream until current capacity requirements are met, are only allowed with a variance approval from the City Engineer. Without a variance approval, projects connecting to City storm drain infrastructure that do not meet current City design criteria shall be required to upsize the existing storm drain system originating at the outfall progressing upstream as required until the system meets current City standards. Providing a detention basin due to insufficient existing storm drain infrastructure capacities in lieu of requirements to upsize the existing storm drain system is subject to acceptance and approval of the City Engineer, with agreement from the impacted City department director(s), and shall not be assumed to be an approved path forward.
Publicly maintained stormwater ponds with permanent pools of water are prohibited except where they provide multiple benefits, including groundwater recharge, flood mitigation, and recreational opportunities consistent with various City Master Plans, including, but not limited to, the Citywide Creek Master Plan, Storm Drain Master Plan (in development as of 7/28/2023), and General Plan. Projects proposing these facilities shall prepare an operation and maintenance plan (O&M Plan), including all annual and recurring costs and how vector concerns will be mitigated. The O&M Plan also needs to include the funding source for the operation and maintenance of the facility. If the funding source is to be the responsibility of the City, the City fund to be used to implement the O&M Plan (e.g., General funds, specific enterprise funds, etc.) needs to be expressly stated and agreed to by the impacted department director(s) and the City Engineer. The O&M Plan must receive approval from all departments with operation and maintenance responsibilities to the feature, which may include Recreation and Parks, TPW, and Water. Grounds for rejection can consist of insufficient funds in the funding source or staff to operate and maintain the asset as outlined in the O&M Plan. Approval may be granted provided the applicant/developer executes a binding agreement to provide funding, in perpetuity, for the operation and maintenance costs associated with these facilities, including City staff time.
Detention basins should be designed to be multipurpose wherever possible and designed to enhance stormwater quality. Detention basins whose primary purpose is water quality enhancement will be considered during planning for storm drain system improvements and in accordance with the current approved regional LID Manual. Detention basins solely for the purpose of LID shall be privately owned, operated, and maintained, unless triggered by a capital improvement project, and do not require a variance for approval. Flows exceeding the detention basin design flows shall be diverted around the detention basin. Overflow routing and design criteria for bypass flows shall be shown on improvement plans including design storm, flow rate, and high-water level.
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Publicly maintained detention facilities for flood control purposes may be permitted, with the approval of the City Engineer, when it is more cost-effective than providing storm drain improvements when there are flow capacity issues in the existing storm drain system. An analysis that justifies the financial need for the detention basin by presenting both the estimated capital cost and the estimated annual operation and maintenance costs of the basin, as well as comparable costs for an underground closed conduit storm drain system, shall be prepared under the direction of a licensed civil engineer and submitted for approval by the City Engineer prior to approval of a tentative map by the City Planning and Economic Development Department.
Approvals of designs shall include approvals from the department director(s) whose departments will be impacted by acceptance of the feature. The City Engineer may prohibit or restrict the use of detention basins based on specific site conditions such as insufficient depth to bedrock; extreme community disruption; insufficient mitigation of vector concerns; need for extensive relocation of existing improvements and utilities; soils with increased risk of instabilities including the Goulding cobbly loam formations; potential for infiltration to negatively impact structures’ soil bearing capacity, design earth pressures, support block envelope, or sphere of influence; existing site or groundwater contamination concerns; or lack of sufficient, available, suitable land. When a project proposes infiltration in Types C and/or D soils and perforated pipe underdrains are not proposed, information must be supplied in the Drainage Reports proving that the design storm will be able to infiltrate into the soils and not create nuisance stagnant water beyond 72 hours after precipitation has ended. When infiltration tests are required, the following American Society for Testing and Materials (ASTM) standards shall be used: D5093 Standard Test Method for Field Measurement of Infiltration Rate Using a Double-Ring Infiltrometer with a Sealed-Inner Ring, D3385 Standard Test Method for Infiltration Rate of Soils in Field Using Double-Ring Infiltrometer, or D8152 Standard Practice for Measuring Field Infiltration Rate and Calculating Field Hydraulic Conductivity Using the Modified Philip Dunne Infiltrometer Test.
The design of detention basins for flood control purposes shall be based on the size of the basin; the maximum allowable depth of temporary ponding; the recurrence interval of the storm being considered; the peak rate, total volume, and timing of the inflow; the maximum allowable outflow rate; and the length of time water is allowed to remain in the basin. The design shall be accomplished through the development of three items: an inflow hydrograph, a depth-storage relationship, and a depth-outflow relationship. These three items shall be combined in a routing routine to obtain the outflow rate, depth of stored water, and storage volume at any specific time as the design storm flow passes through the detention basin. The design considerations and procedures are discussed in Design and Construction of Urban Stormwater Management Systems, Chapter 6, WEF Manual of Practice FD-20, 1992. Publicly maintained detention facilities that require pumping are prohibited unless designed to meet multi-benefit objectives outlined in available City Master Planning level documents, be in accordance with City-wide flood mitigation goals, and be approved by the City Engineer. Provisions for draining private underground vaults shall be included on the improvement plans.
The design considerations cited above determine the detention basin volume required for flood control purposes only. The design of detention basins should also consider other benefits that can be achieved, such as water quality enhancement, groundwater recharge, recreational opportunities, and open space aesthetic enjoyment. Public health and safety needs should be
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considered, such as the need for vector control and fencing in particular applications. Detention basin designs shall promote personal safety by locating the basin along public streets, parking areas, or paved access roads/trails to ensure visual access to the basin area. Site, street, and basin design shall be coordinated to orient buildings and streets for good surveillance of the basin area.
The basin’s geometry should be designed to reduce underutilized zones and increase detention times. Inlet and outlet structures must be carefully designed to reduce turbulence that could resuspend settled solids. Consideration should be given to installing energy dissipators, stilling basins, berms, and separation walls.
To prevent erosion during large storm flows, unprotected side slopes should be no steeper than 3 horizontal: 1 vertical. Steeper banks will only be allowed with the approval of the City Engineer and shall be protected by vegetation and/or planted rock slope protection.
Detention basins shall be designed and constructed to allow for all-weather (paved) driven access into the basin itself and to all inlet and outlet structures. Access to the bottom of the basin is necessary. Basins to be maintained by City staff must meet City accessibility criteria discussed below under "Design Requirements."
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DESIGN REQUIREMENTS
1. CONNECTION TO THE EXISTING STORM DRAIN SYSTEM
1.1. New storm drain systems must connect to existing City, County of Sonoma, or Sonoma Water storm drain infrastructure, ditch, channel, or creek or an approved natural waterway. Storm drain designs shall incorporate the design of any off-site storm drain improvements required to accommodate flow from the storm drain system for the proposed development. A structure must be installed at each connection (i.e., no "blind" connections) except as otherwise approved by variance by the City Engineer.
1.2. Where public storm drains must traverse private property, inlets necessary to drain the private property are permitted to connect to the public storm drain. These inlets and connecting pipes shall be delineated as private on the improvement plans.
1.3. Sump pumps to remove rainwater or groundwater from foundations, basements, or crawl spaces shall not discharge to gutters, sidewalk drains, or storm drain structures unless all feasible alternatives to discharge non-stormwater have been considered and deemed infeasible, which City staff must concur with. If an alternative is not possible:
1.3.1. Sediment and solids shall be removed from the discharge through settling or filtration designs.
1.3.2. To the maximum extent possible, segregate flow to prevent introduction of pollutants. Flows shall be discharged to landscaped areas avoiding directing flows across paved surfaces or gutters where pollutants may be present.
1.3.3. Best Management Practices (such as those outlined in California Stormwater Quality Association manuals), the LID Manual, and vegetation shall be utilized and maintained to prevent erosion and sediment transport.
1.3.4. All sediment removed from non-stormwater discharges shall be collected and disposed of in a timely, legal, and appropriate manner.
1.3.5. When a proposed sump pump site for groundwater, such as from foundations, basements, or crawl spaces, is located within one-half mile of a source of contaminated groundwater as identified on the State Water Resources Control Board’s GeoTracker website (https://geotracker.waterboards.ca.gov/) and/or identified during the project’s Environmental Site Assessments, the sump pumps shall not be permitted to discharge to storm drain infrastructure, ditches, gutters, sidewalk drains, or natural drainage courses without providing treatment prior to discharge and/or the recommended mitigation measures as determined during the Environmental Site Assessments and as approved by the City Engineer. Sump pumps may then discharge by pumping to a jurisdiction structure allowing the water to gravity flow through pipes into a closed conduit system or open channel, if permitted by the North Coast Regional Water Quality Control Board.
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1.3.6. Sump pumps that have potential to discharge liquids other than uncontaminated water (e.g., oil, grease, solvents, etc.) shall discharge to a sanitary sewer, if approved by the City’s Water Department. Industrial pretreatment of these discharges may be required.
1.3.7. Sump pumps installed solely for the purpose of transporting water to a LID feature for water quality shall not be permitted as part of a public facility or public storm drain system without an approved variance from the City Engineer. Sump pumps shall only be used to transport water from privately owned and operated storm drain infrastructure to a private LID feature. Pump stations (not sump pumps) might be permitted when serving multi-benefit needs as outlined in the Detention Basin section of these standards and shall adhere to the requirements in that section including obtaining approval from impacted City department director(s).
1.4. Concentrated drainage flows in pipe systems from private property shall not flow over public sidewalks. Sidewalk drains, sidewalk trench drains, or other means of collection and conveyance to a proper discharge location shall be provided. Sidewalk drains shall be privately owned and maintained including the curb face.
1.5. Lots shall be drained in a manner so as not to adversely affect adjoining properties. No developed lot to developed lot (cross-lot) concentrated overland drainage is permitted (the exception is for lots draining to a common driveway). When cross-lot drainage, such as ditches or environmentally protected features, is allowed, drainage easements and declarations shall be required. Concentrated overland flows, even if a dissipator design is included, must be directed away from buildings and adjacent properties pursuant to 2022 California Building Code (or most current version), Part 5 California Plumbing Code, Chapter 11 Storm Drainage.
2. MATERIALS
2.1. Storm drain pipes 15 inches in diameter or larger shall be reinforced concrete pipe (RCP), annular high density polyethylene (HDPE) pipe, or high-performance polypropylene (HPPP) pipe. Cast-in-place pipe is not permitted. Use of HDPE and HPPP for storm drain, including pipes, flared end sections, and pipe inlets, will not be accepted for publicly owned and maintained storm drain systems in Wildland-Urban Interface (WUI) Fire Areas as defined by the current City WUI map. For Public storm drain systems outside of WUI Fire Areas, HDPE and HPPP, including pipes, flared end sections, and pipe inlets, shall not be permitted as inlet/outfall structures or between an inlet/outfall that daylights, such as a flared end section or headwall, at a vegetated area, ditch, or creek and the next downstream/upstream storm drain structure in the storm drain system. HDPE and HPPP shall not be accepted where they connect to a structure that is located in an unpaved area, such as field inlets in ditches or LID features.
Changes in pipe material shall only occur at structures. Plastic perforated pipes located in LID features as part of the LID design are exempt from this rule and will continue to be allowed to connect to structures located in unpaved locations.
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2.2. RCP shall be Class III, IV, or V as specified in Part III, Public Storm Drain Construction Standard Specifications, of these standards.
Typical total effective loads on buried pipe, expressed in pounds per linear foot of pipe, are shown in Table I-1. The design engineer shall determine the D-load for the depth and diameter of pipe from the table and select the class of RCP with a D-load rating equal to or greater than the value in Table I-1. The design engineer shall interpolate between the values in Table I-1 for conditions not presented in the table.
2.3.HDPE and HPPP pipe for publicly owned and maintained infrastructure shall only be used in sizes of 48 inches or smaller diameter pipes with cover of less than 30 feet. The design engineer shall determine flotation restraint per manufacturer’s recommendations.
Loading on buried pipes shall be able to meet loads as outlined in Table I-1, American Association of State Highway and Transportation Officials (AASHTO) H-25, H-20, and HL-93 loads, and shall have a minimum depth of cover per City Standard details and as determined per the manufacturer’s recommended specifications. HDPE and HPPP pipe shall have a 36-inch minimum cover in unimproved areas. The HDPE and HPPP pipe walls must be free of cracks, holes, voids, blisters, foreign inclusions, scratches deeper than 10% of the wall thickness, or other defects visible to the naked eye or affecting the pipe wall integrity. The residue from the ignition of HDPE or HPPP compounds must not exceed 30 percent as determined under ASTM D2584 except the muffle furnace temperature must be 840 ± 45 degrees Fahrenheit.
2.4. HDPE pipe shall be smooth interior, corrugated exterior (Type S) pipe with bell-and- spigot joints per AASHTO Designation M294.
2.5. HPPP pipe shall be smooth interior, corrugated exterior (Type S) pipe meeting or exceeding ASTM F2881 or AASHTO M330 with bell-and-spigot joints meeting ASTM D3212.
2.6. Sidewalk drains shall be per SD Standard 406.
2.7. Sidewalk trench drains shall be per SD Standard 406C.
2.8. Wood storm drain structures, covers, or lids shall not be permitted within City jurisdiction under any circumstance. Any existing wooden storm drain component in need of repair or replacement shall be replaced with a concrete City standard structure, metal cover/lid, and/or metal grate. Projects connecting to or fronting wooden storm drain structures shall be required to replace the wooden structure(s) or components with a concrete structure and metal components as part of their required frontage improvements.
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3. SIZE
3.1. Storm drain pipe diameters within the public right-of-way, including driveway culverts, shall be 15 inches or larger when self-cleaning velocities can be met, except perforated subdrains, sidewalk drains or sidewalk trench drains, which shall be per SD Standard 406 and 406C, respectively.
3.2. In new portions of the storm drain system, pipe sizes shall not decrease in the downstream direction. This design requirement doesn’t apply to hydromodification facilities.
4. ALIGNMENT
4.1. Storm drain pipes shall be located within public streets unless a variance is approved by the City Engineer.
4.1.1. Storm drain mains shall be aligned so that the outside of the pipes are a minimum of one (1) foot from the lip of gutter. An exception shall be allowed where the existing storm drain main does not meet this requirement and is not proposed, or required to, realign the existing main (e.g. a new junction structure is proposed to supply a lateral connection to avoid a blind connection, required current City standard roadway section aligns new gutter over the existing storm drain main, etc.).
4.1.2. 48-inch manholes shall be centered a minimum of three (3) feet from the lip of gutter. 60-inch manholes shall be centered a minimum of four (4) feet from the lip of gutter.
4.2. Storm drains traversing private property shall be straight between manholes (i.e., no horizontal curves) unless otherwise approved by a variance, in which case the pipe shall be centered within the easement dedication, or when installed in a private street parallel to the centerline of the private street.
4.3. In general, storm drains shall be installed parallel to the centerline of the street or right- of-way.
4.4. Horizontal separation of storm drain line from sanitary sewer shall be a minimum of five (5) feet clear (i.e., outside of pipe to outside of pipe), except at pipe crossings, or as required by the City’s Sanitary Sewer Design Standards.
4.5. Horizontal separation from water mains and other utilities, gas, underground electric, underground television cable, etc., shall be a minimum of four (4) feet clear (outer walls), except at pipe crossings, or as required by the City’s Water Distribution Design and Construction Standards.
4.6. Vertical curves are not allowed unless a variance is approved by the City Engineer.
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4.7. Horizontal curves with a minimum radius of 300 feet for RCP shall be provided at catch basins installed at curbs and gutters to locate as much of storm drain as possible under asphaltic concrete paving rather than concrete curbs and gutters.
4.8. Horizontal curves concentric with public or private street centerlines may be permitted with RCP provided the radius is 300 feet or greater. Horizontal curves in HDPE and HPPP pipe may be achieved using 3° mitered couplings with no joint or pipe deflection unless otherwise specified in the manufacturer’s specifications. A minimum of 10 feet of pipe shall separate mitered couplings.
4.9. Horizontal curves can be installed in RCP by pulling pipe joints if the resulting deflections are not greater than the pipe manufacturer's recommendations. The design engineer shall use the following equation in designing horizontal curves for RCP with a diameter over 48 inches:
𝑅= 𝐿
2(𝑇𝑎𝑛1
2 ∆
𝑁)
where:
R = radius of curvature of the centerline of the pipeline in feet L = laying length of pipe section in feet, measured along centerline ∆ = total deflection angle of curve in degrees
N = number of pipe sections with pulled joints
∆/N = deflection angle of each pipe in degrees
4.10. An access structure shall be installed when total horizontal deflection exceeds 45 degrees.
5. SLOPE
5.1. Minimum slopes shall achieve a half-full flow velocity of three (3.0) feet per second or greater for the required design storm (excluding 100-year storm) for closed conduit systems. Pump stations may be required where there are no other practical solutions and self-cleaning velocities cannot be met. Except where located to serve public storm drain main outfalls to open channels, or where public storm drain mains cannot maintain positive drainage, new pump stations serving private developments shall be privately owned and maintained. A variance approved by the City Engineer shall be required for proposed systems not achieving a minimum half-full flow velocity of three (3.0) feet per second. It should not be assumed a variance will be granted. These calculations are required in all drainage reports. Where proposed pipes are connecting between existing storm drain main inverts controlled by the previously allowed two and a half (2.5) feet
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per second velocities, an exception can be granted without requiring the need for a variance.
5.2. Minimum slopes for earth channels, ditches, and hardened or concrete-lined channels for City owned and maintained channels shall achieve a velocity of two and a half (2.5) feet per second based on the design flow calculations.
5.3. Minimum slopes for Sonoma Water owned and maintained channels shall meet the current Sonoma Water FMDM design requirements.
5.4. Maximum slope for storm drains shall be 15 percent or 15 feet per 100 feet.
5.5. All City maintained storm drain systems shall drain by gravity achieving the minimum velocities to the receiving waters or existing storm drain systems. Systems where the inverts out are at a higher elevation than inverts in (i.e., “bubble-up”) designs on public or private storm drain mains and laterals are prohibited and are not subject to variance approval by the City Engineer as they are a violation of California State Health and Safety Code Division 3, Chapter 1, Article 5, Section 2060 et. al. Therefore, it is not within the City’s or City Engineer’s purview to grant variances from the MSMVCD or State Health and Safety Code requirements. Private storm drain systems are allowed to install private pump stations that shall have both low-flow and high-flow needs designed appropriately and pump station design and cycling calculations are required in the project’s drainage report. Publicly owned and maintained pump stations shall only be allowed where the existing system does not meet current design standards, the minimum slopes cannot be maintained to the outfall location due to existing grade of channels, or as approved by variance by the City Engineer. All public and private pump stations shall have a trash capture component incorporated into the design and be oriented prior to the pump intake(s). The trash capture component shall comply with current MS4 and California statewide trash capture requirements. Neglecting to perform industry standard due diligence in design, including neglecting to obtain pothole information in design prior to final approved improvement plans, shall not warrant grounds for a variance approval to this clause.
5.5.1. Bubble-ups are still permitted for individual lot back of lot drains and some applications for LID designs including pipes less than six-inch diameter. These systems by design shall have no ponded water remaining beyond 72 hours due to vector breeding concerns. This can be achieved through infiltration (e.g., one or more sticks of plastic perforated pipe with gravel trench similar to French drain designs) or by other design features including mesh covers at inlet with debris control and pop-up emitters. Neither public nor private site storm drain lines greater than six inches that cannot eliminate ponded water within 72 hours shall be allowed and variances will not be granted as it is not within the purview of City authority.
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6. COVER
6.1. Minimum cover over storm drains shall be 12 inches (Class III RCP, HDPE and HPPP) below bottom of a roadway structural section and three (3) feet below finish grade, whichever is greater. Refer to Table I-1 for RCP. Loading on HDPE and HPPP buried pipes shall be able to meet loads as outlined in Table I-1, American Association of State Highway and Transportation Officials (AASHTO) H-25, H-20, and HL-93 loads, and shall have a minimum depth of cover per City Standard details and as determined per the manufacturer’s recommended specifications. HDPE and HPPP pipes shall have a 36- inch minimum cover in unimproved areas. When cover does not meet these standards, a concrete backfill with steel reinforcement shall be required per SD Standard 412.
7. MANHOLES AND OTHER STRUCTURES
7.1. A manhole or accessible structure shall be installed at every change in pipe size.
7.2. The maximum distance between manholes and/or accessible structures shall be 300 feet.
7.3. Manholes shall be placed on horizontal curves once the curve has reached 45 degree of total deflection and for each segment of the curb that reach a 45 degree of total deflection.
7.4. A manhole or accessible structure shall be installed at every horizontal angle point or vertical change in alignment.
7.5. Standard drop between inverts in and inverts out shall be 0.10 feet whenever possible and when not limited by existing storm drain infrastructure elevations.
7.6. Manholes shall be 48 inches in diameter with storm drain pipes of 36 inches diameter or less, and shall be 60 inches in diameter with storm drain pipes larger than 36 inches in diameter. Manholes shall be designed to be large enough to accommodate all pipes connected to manhole with a minimum of 3 inches of manhole wall on both sides of all pipes. Reducer slabs may be provided as shown on SD Standard 401 in Section A-A.
7.7. Manholes shall be provided at both ends of storm drain infrastructure needing to be maintained or serviced, especially underground detention systems, including public and privately owned and maintained systems.
7.8. An accessible structure shall be provided to connect private storm drains to the public storm drains (i.e., no blind connections) except as otherwise approved by the City Engineer. Structures shall be installed on the private side of the property line to distinguish the public system from the private system. Public and private storm drain facilities shall be clearly identified on the improvement plans. For residential land uses only, no structure is necessary for sump pump connections to public storm drain systems. Accessible structures are required for sump pump connections from non- residential land uses.
City of Santa Rosa | Public Storm Drain Standards | [Date] 15
7.9. Headwalls, wing walls, flared end sections, or structures shall be provided where open ditches, channels, and creeks discharge into closed conduits or where closed conduits discharge to ditches, channels, and creeks. Refer to Caltrans’ Highway Design Manual and Standard Plans.
7.10. Flared end sections shall be metal. Plastic flared end sections are not permitted as part of publicly owned and maintained infrastructure as they interface with vegetated areas.
7.11. Rock slope protection is required where open ditches, channels, or creeks enter a closed conduit or where a closed conduit discharges to an open ditch, channel, or creek.
Rock slope protection shall be sized to the controlling flow velocity. Where a closed conduit discharges to a hardened channel, such as a concrete lined channel, or a hardened channel transitions to a closed conduit, rock slope protection shall not be required. For example, where a relatively small, closed conduit (e.g., 15-inch culvert) discharges to an established creek, the creek velocities must be calculated, and the creek velocities would be the controlling factor in sizing the rock slope protection for the closed conduit outfall. Rock slope protection shall be sized following SD Standard 407.
8. STORM DRAIN INLETS
8.1. Catch basins shall be Type II (SD Standard 402) except as listed below or as otherwise approved by the City Engineer. Galleries per SD Standard 404 may be used on the upstream side of a Type II catch basin to increase inlet interception capacity or if their use reduces the number of catch basins requiring maintenance.
8.2. Flow in gutters must be accounted for in the determination of the design and layout of storm drain inlets. Design depth of flow in gutters should not exceed 0.4 feet for the 10- year flow and calculations to be consistent with Sonoma Water’s FMDM guidelines.
Storm drain inlets must be sized and located to limit the flooded width from entering the traveled lanes for the design storm (refer to U.S Department of Transportation Federal Highway Administration’s (FHWA) Hydraulic Engineering Circular (HEC) No. 22, 3rd Edition dated September 2009 revised August 2013, or most current version, for further technical guidance). Gutter flooded width calculations must be supplied with the supporting drainage calculations for Projects. When storm drain inlets are to be replaced, flooded width must be calculated and improved to meet this requirement with larger grates, combination inlets, and/or use of a SD Standard 404 storm drain gallery.
8.3. Standard drop between inverts in and inverts out shall be 0.10 feet whenever possible and when not limited by existing storm drain infrastructure elevations.
8.4. Catch basins shall be installed at the following locations:
8.4.1. Such that gutter flows do not cross intersections except where valley gutters are allowed.
City of Santa Rosa | Public Storm Drain Standards | [Date] 16
8.4.2. Immediately upstream of bridge abutments.
8.4.3. The beginning of every roadway superelevation that reverses the cross-slope of the pavement.
8.4.4. The sags (i.e., bottoms) of vertical curves. Catch basins on sags shall have either a curb opening component, gallery per SD Standards 404, or two flanking inlets at all sags.
8.4.5. For projects subject to the City’s Hillside Development Ordinances, when the longitudinal roadway slope is 10% or greater and the roadway makes a perpendicular direction change or a knuckle is proposed, a catch basin shall be located at the upstream beginning of the outer radius alignment.
8.4.6. The low points of downhill cul-de-sacs
8.4.6.1. For projects subject to the City’s Hillside Development Ordinances and requirements, roadways shall be crowned to the center point of the bulb radius at a minimum slope of 2%. Due to hydraulics of roadways, variances from this are strongly discouraged. Should a variance be approved by the City Engineer, calculations and potentially modeling will be required to be submitted with the Drainage Report. The calculations must show there are sufficient catch basins upstream of the low point to contain the design flows in the gutter pan. Ponded width shall not be permitted to extend into the pavement section from the gutter pan. Calculations and modeling will need to show that given the velocities and flows, the design flows will not encroach over any downstream driveway approaches at the back of sidewalk catch point.
8.4.7. As required so that water depth in gutter does not exceed 0.4 feet during the design storm event.
8.4.8. As required to maintain the following number of 8-foot-wide traffic lanes unimpeded by flowing or standing water during a design storm:
8.4.8.1. Two lanes for all regional streets.
8.4.8.2. One lane for transitional and industrial streets. This lane may be in the middle of the road, spanning the crown. This requirement does not apply to local streets.
8.4.8.3. One lane in each direction for transitional streets that are divided roads or roads with a median strip.
8.4.9. As required so that carry-over flows (bypassing catch basins) for a 10 year shall not exceed 2 cubic feet per second.
City of Santa Rosa | Public Storm Drain Standards | [Date] 17
8.4.10. At a maximum spacing of 300 feet from another catch basin or manhole (i.e., maximum length of storm drain pipe without a structure is 300 feet).
8.5. Catch basin size and spacing shall be computed by the methods in FHWA HEC-22.
9. STUB CAPS
9.1. Upstream terminations of new storm drain systems where a single stub pipe segment has been provided for future expansion, a minimum of six (6) feet of pipe from a structure shall be provided. Cap or seal the last section of pipe by one of the following methods:
9.1.1. For HDPE or HPPP pipe, use a manufacturer-approved cap.
9.1.2. For RCP, install an additional section of pipe and fill with concrete or install a plywood seal to the end of pipe not to exceed the outer diameter of the pipe. Install concrete stub cap per SD Standard 411.
10. VIDEO INSPECTION
10.1. All new and modified storm drain pipes shall be inspected per Section 79 of the City of Santa Rosa Storm Drain Standard Specifications.
11. ABANDONMENT OF STORM DRAIN PIPES
11.1. Any existing storm drain pipe that will not be used and is to be abandoned, the following shall be noted on the Improvement Plans:
11.1.1. All storm drain pipes to be abandoned shall be done per City Standard 507.
12. EASEMENTS
12.1. An easement shall be provided over any public storm drain when it is installed outside a public right-of-way.
12.2. The easement shall be a minimum of 15 feet wide if it only contains a publicly maintained storm drain or 20 feet wide (or wider) if it contains another facility, such as water, sewer, or other utility. The easement will be dedicated as a "public drainage easement" if it contains storm drain only. It will be dedicated as a "public utilities easement" if it contains other facilities as well. If an existing easement is less than the specified widths above, the existing easement will be required to be expanded to the current 15-foot minimum width. A variance will be considered if expanding the easement to 15 feet wide will impact existing buildings.
12.3. Easements shall be configured to encompass all publicly maintained appurtenances and will be generally centered over the facility. Separate access easements may be required depending on site conditions. When storm drains are to be installed along a property line the easement will be wholly contained on one parcel.
City of Santa Rosa | Public Storm Drain Standards | [Date] 18
12.4. Clear access shall be provided and maintained to all public infrastructure of the public storm drain system. Where fences are proposed that span a public drainage or utility easement on any development, including subdivisions, the improvement plans shall show that movable gates spanning the width of the entire easement must be provided.
12.5. All property restrictions placed as a result of dedication of easements will be so noted on the supplemental sheet of the Subdivision Map, or on the Easement Deed if the easement is not dedicated as part of a subdivision. Typical required notes as applicable are:
12.5.1. No structures shall encroach on, above, or below the surface of the ground in any public easement. This includes footings of foundations, eaves from the roof of any adjacent structure, pools, ponds, MS4 permit required LID features, fences without a movable gate across the entire width of the public easement, or outbuildings on slabs or foundations. Any structure on, above, or below the ground surface in a public easement damaged as part of maintenance activities for the storm drain will be the responsibility of the property owner at no fault to the City.
12.5.2. Fences shall not be installed along the longitudinal alignment over the storm drain pipes and structures. Any fences installed crossing a storm drain easement must provide vehicle access through the fence within the storm drain easement.
12.5.3. Trees shall not be planted in easements with public storm drain including “public drainage easements” and “public utility easements”.
12.5.4. The City will take due caution when performing maintenance or repair of drainage systems in easements, but will not be responsible for repairs or replacement of trees, landscaping, fences where gates spanning the width of the easement haven’t been provided, or structures not specifically approved in recorded writing by the Director of Transportation and Public Works or by approved variance from the City Engineer. Variances approved to legalize existing structures may be granted, but shall include clauses noting that it is a one-time variance and that the City retains the right to fully use the entire width of the easement without being liable for impacts to the encroaching structure or feature should it be needed to operate or maintain the public infrastructure.
13. ACCESS ROADS
13.1. Access shall be provided and kept clear to accommodate maintenance of all public storm drain system facilities within public drainage easements and public utility easements.
13.2. All-weather vehicle access roads are required to access every structure on the storm drain system within the public drainage or utility easement. Access roads must be
City of Santa Rosa | Public Storm Drain Standards | [Date] 19
a minimum width of 12 feet and must be provided with turnarounds per City Standard 206 when the back-up distance for any maintenance vehicle exceeds 100 feet.
13.3. The design of access roads must be included with the drainage system design plans. At a minimum, the design will conform to the requirements of City Standard 216.
Include adequate drainage measures in the design to prevent damage to the access roads from stormwater.
13.4. Gates must be provided for access through any fence crossing a public drainage or utility easement the width of the easement to a maximum required gate width of 12 feet.
Gates installed across public easements are the responsibility of the property.
13.5. The maximum grade allowed at any point on an access road is 15%. The maximum cross-slope for any access is 5%.
14. .MAINTENANCE
14.1. Storm drains that convey public water, designed and constructed to City standards and in a dedicated public easement or right-of-way accepted by the City shall be maintained for hydraulic capacity by the City. All other storm drains, including driveway culverts, shall be privately maintained.
14.2. Sidewalk drains shall be privately maintained by the owners of the fronting property.
15. WATER QUALITY
15.1. Source controls designed or constructed to reduce the discharge of pollutants from the stormwater conveyance system, otherwise known as LID, shall be designed and maintained per the current version of the Regional LID Manual.
15.2. Tire-derived aggregate and reclaimed processed asphalt concrete grindings shall be prohibited for use within the City’s jurisdiction. The allowable exception to this clause is when reclaimed processed asphalt concrete grindings are used and bonded as part of full-depth reclamation construction practices where the grindings are thereby encapsulated as the new, sealed pavement section.
15.3. The City Engineer may prohibit or restrict design of infiltration features, including LID features, based on specific site conditions such as insufficient mitigation of vector concerns; need for extensive relocation of existing improvements and utilities and/or justified rejection of relocation by the utility owner; soils with increased risk of instabilities including the Goulding cobbly loam formations; potential for infiltration to negatively impact structures’ soil bearing capacity, design earth pressures, support block envelope, or sphere of influence; or existing site or groundwater contamination concerns.
15.4. When infiltration tests are required, the following ASTM standards shall be used:
D5093 Standard Test Method for Field Measurement of Infiltration Rate Using a
City of Santa Rosa | Public Storm Drain Standards | [Date] 20
Double-Ring Infiltrometer with a Sealed-Inner Ring, D3385 Standard Test Method for Infiltration Rate of Soils in Field Using Double-Ring Infiltrometer, or D8152 Standard Practice for Measuring Field Infiltration Rate and Calculating Field Hydraulic Conductivity Using the Modified Philip Dunne Infiltrometer Test.
16. OTHER REQUIREMENTS
16.1. The National Oceanic and Atmospheric Administration’s (NOAA) Atlas 14 and NOAA’s National Weather Service the Atlas 14 Precipitation Frequency Data Server, or current versions, online tool shall be used to determine design storm intensities and intensity-duration-frequency curves.
16.2. For any hydrology or hydraulics design criteria not expressly stated in these SD Standards, including the quick reference sheet, the following references, listed in order of hierarchy, shall be complied to for design and calculation criteria:
16.2.1. Current version of Sonoma Water’s Flood Management Design Manual
16.2.2. Current versions of Caltrans Highway Design Manual, Standard Plans, and Standard Specifications
16.2.3. Current versions of FHWA’s HECs including, but not limited to, HEC-14 and HEC-22.
16.3. Sanitary sewer laterals and industrial process or waste pipelines shall not be connected to storm drains or allowed to discharge to waterways. Sanitary sewer laterals and industrial waste pipelines shall be connected to sanitary sewers in conformance with the latest edition of the City's Sewer Standards; pretreatment of industrial wastes may be required.
16.4. Driveway culverts shall be designed under the direction of a licensed civil engineer to convey anticipated flow from future development and ensure hydraulic adequacy. Corrugated metal pipe compliant with Sonoma County Standards STD-820 Driveway Drainage Culverts, or the current version, can be used for driveway culverts.
16.5. Field verification of utility locations during design (including potholing where necessary) is the full responsibility of the design engineer. Utility conflicts discovered during construction due to inadequate field verification of utility locations during design does not constitute grounds for a variance approval. Design engineers shall not assume public or private utility owners will allow partial or full relocation of existing utilities that conflict with the design.
TABLE I-1 LOADS ON BURIED PIPES
POUNDS PER LINEAR FOOT
City of Santa Rosa | Public Storm Drain Standards | [Date] 21
in feet 15 18 21 24 27 30 36 42 48 54 60 66 72 78 84 90 96 102 1081 * * * * * * * * * 2919 2310 2475 2310 2169 2048 1944 1852 1778 17052 1632 1592 1549 1516 1491 1471 1474 1289 1148 1039 952 881 822 772 729 692 659 633 6073 931 893 859 834 814 798 827 814 797 784 731 688 652 622 596 573 553 540 5244 857 816 780 753 733 716 760 742 723 709 699 691 685 658 636 616 599 589 5765 878 832 794 766 744 726 784 763 742 726 715 706 699 693 687 683 667 660 6476 921 874 833 803 780 762 835 812 789 771 759 749 741 735 729 724 719 727 7207 974 924 883 852 828 809 897 872 848 829 816 806 798 790 784 779 775 782 7788 1029 978 935 904 880 861 964 939 913 893 880 869 861 853 847 842 837 846 8429 1087 1036 993 961 937 918 1037 1011 985 964 951 940 932 924 918 913 908 918 91410 1141 1090 1047 1015 992 973 1108 1082 1055 1034 1021 1011 1002 995 989 984 979 991 98711 1191 1141 1098 1067 1043 1026 1177 1151 1123 1103 1090 1080 1072 1065 1059 1054 1050 1063 105912 1236 1187 1145 1115 1092 1075 1242 1217 1190 1170 1157 1148 1140 1134 1128 1124 1120 1135 113114 1315 1269 1229 1201 1181 1166 1365 1343 1317 1297 1287 1279 1272 1267 1263 1260 1257 1275 127216 1380 1338 1301 1276 1259 1247 1477 1458 1434 1417 1409 1403 1398 1395 1393 1391 1389 1411 140918 1433 1396 1363 1341 1327 1318 1578 1564 1543 1528 1523 1519 1517 1516 1516 1516 1516 1542 154220 1477 1445 1415 1397 1386 1380 1670 1661 1643 1631 1629 1629 1630 1631 1633 1635 1637 1668 166924 1542 1519 1496 1485 1482 1483 1828 1830 1820 1816 1821 1828 1835 1842 1850 1857 1863 1903 190828 1585 1570 1554 1550 1553 1560 1955 1969 1969 1973 1987 2002 2016 2030 2043 2056 2068 2118 212632 1613 1605 1595 1597 1606 1619 2058 2085 2094 2107 2130 2153 2175 2196 2216 2235 2253 2313 232636 1632 1629 1624 1631 1646 1664 2141 2180 2198 2220 2253 2285 2315 2343 2371 2396 2420 2490 250940 1644 1645 1644 1656 1675 1698 2208 2258 2286 2317 2359 2399 2437 2474 2508 2540 2571 2651 2675Pipe Diameter In Inches Allowable Loads:Class III 1,350 pounds/linear footClass IV 2,000 pounds/linear footClass V 3,000 pounds/linear footThe area within the heavy black line indicates situation where Class III RCP is acceptable. * Exceeds the capacity of Class V RCP. Special design required to be submitted to City Engineer.Reference: Ameron Reinforced Concrete Pressure Pipe, 1971, for covers of 2 feet or greater. Loads are interpolated for cover of 1 foot.
Cover to SubgradeTHIS CHART IS TO BE USED IF EQUIPMENT OR VEHICLES WILL BE DRIVEN ON SUBGRADE. IF PIPES ARE TO BE INSTALLED IN EXISTING ROADWAY OR PAVED AREAS, MINIMUM COVER SHALL BE CALCULATED USING THE EXISTING STRUCTURAL SECTION.
City of Santa Rosa | Public Storm Drain Standards | August 2023 22
II. PUBLIC STORM DRAIN STANDARD DETAILS
Std. Title Approved
400 Standard Precast Concrete Storm Drain Manhole [Date] 401 Precast Concrete Storm Drain Manhole Reducer Slabs [Date] 402 Type II Catch Basin [Date]
403 Type I Catch Basin [Date]
404 Storm Drain Gallery [Date]
405 Precast Catch Basin Cover [Date]
406A 3" Sidewalk Drain [Date]
406B 3" x 12-1/2" Cast Iron Sidewalk Drain [Date]
406C Trench Drain and Grate [Date]
407 Rock Slope Protection Storm Drain Outlet/Inlet [Date] 408 Precast Side Opening Field Drain [Date]
409 Storm Drain Labels [Date]
410 Reinforced Concrete Pipe Collar [Date]
411 Reinforced Concrete Stub Cap [Date]
412 Concrete Bedding Cap [Date]
413 Street Bioretention Bulb-Out, Mid-Block, Corner Crossing [Date] 414 Curb Cut Inlet/Outlet For Planters [Date]
415 Storm Drain Under Curb or Planter [Date]
STANDARD CONCRETE
STORM DRAIN MANHOLE
FILE NO:
STD - 400
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DRAFT MARCH 2025
DWN: EDS
CHK:
APPROVED:
1. 2.
3. 4.
5. 6.
When manholes are installed in unimproved areas,
the top of the cover shall be a min. of 1 foot above
adjacent finished grade.
Min. of one 3" grade adjustment ring. Max. height of
grade adjustment ring=20". Alternatively, contractor
may cast grade adjustment rings in place.
Set all sections in 1:3 mortar bed. Wet both tongue
and groove before applying mortar. Wipe inside of
joint smooth and plaster outside of joint with 1/2"
layer of mortar. Ram-nek gaskets or approved equal
may be used instead of mortar.
Cone section (taper) may be concentric or eccentric
unless otherwise specified by the Engineer.
All precast manhole sections per ASTM C478.
Class "A" conc. collar shall be 2" below top of
manhole cover in improved surface areas.
Poured-in-place base shall be poured full
thickness to undisturbed sides of
excavation, sloped at 1:1 or shall be formed.
Precast base shall be from City Engineer's
approved list and be placed on 6" thick 3/4"
drain rock sub-base installed against
undisturbed earth.
7. APPROVED 48" & 60" PRECAST
STORM DRAIN MANHOLE
COMPONENTS
See Engineer's approved list
Grout all voids between
manhole and pipes and seal
joints with 1:3 mortar.
See note 3
For manhole cover and frame
see STD. 512. Cover to be
Labeled "STORM DRAIN".
Pick holes may be open or closed
UNIMPROVED SURFACE
IMPROVED SURFACE
Asphalt
concrete
Finished grade
Level with 1:3
mortar. 1" min.
Concrete collar.
See note 6.
24" min.
8"
min.
8"
min.
12"
min.
48" OR 60" I.D.
PRECAST BASE
POURED IN PLACE
(Both acceptable for unimproved and improved areas.)
Form smooth flow
channel in base.
Use impression ring to
form keyway for cone or
additional barrel section.
6" minimum if
poured in place.
Class 'A" concrete
base (See note 7).
See note 7
Concrete collar required
per STD-410.
PRECAST CONCRETE STORM
DRAIN MANHOLE REDUCER
SLABS
FILE NO:
STD - 401
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
1. 2.
3. 4.
Reducer slab shall be designed to withstand H20
loading and conform to ASTM C478.
All inside joints to be grouted smooth.
Class A concrete collar shall be poured to 2" below
finished grade.
Reducers shall be concentric. Eccentric reducers can
be used if it would place the opening in a more
desirable location or improve access.
For detail and specifications of
barrel section and base see
City of Santa Rosa STD. 400
APPROVED 48" & 60" MANHOLE REDUCER SLAB
See Engineer's approved list
48" OR 60" I.D.
Finish grade
SECTION A-A
24"
Concrete collar. See
STD. 400
Minimum (1) 3" grade
adjustment ring.
See note 1
See STD. 400
Level with 1:3
mortar, 1" min.
Asphalt Concrete
Standard manhole frame and cover,
see STD. 512. Cover to be labeled
"STORM DRAIN". as noted on this
sheet. Pick holes may be open or
closed. to be open.
8"
8"
#5 lifting eye (TOTAL 2). Lifting eye to
be located at balance point
A
A
Grid pattern
STORM DRAIN
"CITY OF SANTA ROSA"
Standard 24" heavy duty, non
rocking manhole frame and
cover.
DRAFT MARCH 2025
TYPE II CATCH BASIN
FILE NO:
STD - 402A
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
1. 2.
3. 4.
5. Catch basin box, and lid if not a
monolithic pour, shall be constructed
to withstand H20 loading. Cover is
not traffic rated.
Concrete shall have a compressive
strength of 4000 psi in 28 days.
Wall thickness shall be 6" unless
depth is greater than 8', then wall
thickness shall be 8".
Install label per City STD. 409 if cover
is not a cast iron cover with the decal
incorporated into the cast iron.
A concrete collar per STD-410 is
required when a pre-cast lid is placed
on a pre-cast box.
APPROVED TYPE II CATCH BASINS
See Engineer's approved list
SECTION B-B
B
SECTION A-A
48"
48"
48"
6"
LIP OF GUTTER
BACK OF CURB
24"
FACE OF CURB
B
A
A
PLAN
TOP OF CURB
GUTTER FLOW LINE
6"
8"
32"
8"
24"
MIN.
6" MIN.
6" MIN.
SEE NOTE
3 GUTTER FLOW LINE
FACE OF CURB
PRECAST CATCH BASIN
COVER. SEE STD-405
BACKFILL
SEAL JOINT
WITH GROUT
6" MIN. 3/4" DRAIN ROCK
INSTALLED AGAINST
UNDISTURBED EARTH.
CONCRETE
COLLAR
REQUIRED PER
STD-410
INSTALL WEEP
HOLE
SEE STD-402D
SEE
NOTE 5
DRAFT MARCH 2025
SEE
NOTE 5
TYPE II CATCH BASIN
FILE NO:
STD - 402B
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
1. Include total of two open #5
lifting eyes to be located at
balance point. Lifting eyes shall
not be blocked by the rim and
shall pass through width of lid.
When "DRAINS TO CREEK"
modification is not available,
affix label per STD-409.
CATCH BASIN COVER
48"
48"
6"
LIP OF GUTTER
BACK OF CURB
24"
FACE OF CURB
PLAN VIEW
LIFTING EYE,
SEE NOTE 1.
24"
28"
25-1/4"
25-1/2"
26-1/2"
2"
1/2"
1/2"
SECTION B-B
B
B
NON TRAFFIC
CAST IRON
LIFTING EYE,
SEE NOTE 1.
2-#4 REBARS (TYP)
T
T
T=6" OR 8", SEE
NOTE 3 ON
STD-402A
CORNER
DOWEL
4"
4"
4"
2"
2"
#4 DEF BARS
(SPACED AS
SHOWN)
48"
4"X4" - 6 AWG MESH MAY
BE USED IN LIEU OF
REBARS. (SEE NOTES ON
SD-1-4)
CORNER DOWEL (SEE
DETAIL ON STD-402C)
CORNER
DOWEL
2"
ANCHOR
ANCHOR
DRAFT MARCH 2025
A
A
SEE NOTE 2
2. TYPE II CATCH BASIN
FILE NO:
STD - 402C
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
CORNER DOWEL DETAIL
SECTION A-A
(FROM STD-402B)
#4 BAR
8"
90 90
2"
ROADWAY OR CONC. GUTTER
SUBGRADE OR BASE
INSTALL WEEP HOLE
3" DIA.
INSTALL GUARD ROD
T=R
REINFORCE SIDE WALLS WITH
#4 BARS AT 12" EACH
DIRECTION
PIPE DIA + 12"
(3'-0" MIN)
DOWEL PLACED AT EACH CORNER
(SEE DETAIL BELOW)
SEE STD-402D
1/4" R
CAST IRON FRAME AND
COVER (SEE STD-402B)
3"
1-3/4"
1-1/2"
10 GA. X 2-3/4" GALV. RING
T
T
DRAFT MARCH 2025
NOTES:
1. 2.
Floor shall be poured and approved
prior to pouring of the top.
See STD-402E for additional notes.
TYPE II CATCH BASIN
FILE NO:
STD - 402D
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
THROAT OPENING DETAIL
NOTES:
1. 2.
All metal parts shall be hot dipped
galvanized after fabrication.
All galvanized damaged by welding shall
receive two coats of aluminum paint.
R=6" or 8"
Gutter flow
line
Batter to conform to adjoining curb
3-1/2" X 2" X 1/4"
galvanized steel nosing
angle
1/2" dia. anchor at
each end
Guard
rod
ALL AROUND
Sidewalk slope
1/4" R
Curb line
1-1/2"
#4
6 1
Curb face
5"
DRAFT MARCH 2025
TYPE II CATCH BASIN
FILE NO:
STD - 402E
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
NOTES:
1. 2.
3. 4.
5. 6.
7. 8.
9. 10.
11. 12.
Connection pipes may be placed in any position around the walls provided the point in the proper direction and the position is otherwise consistent with the improvement plan.
Curvature of the lip and sidewalls at gutter opening shall be formed by curved forms and shall not be made by plastering.
Wall thickness (T)
Depth (H) shall be a maximum of 6 feet. For depths between 6 feet to 12 feet, catch basin shall be on a manhole base, see STD-400C. For depths greater than 12 feet deep require a special design by a registered civil engineer.
Floor of basin shall be troweled and re-troweled to produce a hard, polished surface of maximum density and smoothness. Slope of floor parallel with curb shall be 1 to 12 unless otherwise specified.
Manhole shall be placed as shown on improvement plans.
Outlet pipe shall be trimmed to the final shape and length before concrete is poured.
Reinforcing steel shall be #4 round deformed bars, or wire mesh as indicated. If wire mesh is used, additional 4"X4" 6 AWG mesh shall be placed around the inlet opening @45 degrees to main mesh reinforcing.
Concrete shall meet the requirements of section 90-2 "Minor Concrete" of State Standard Specification.
Steps: Steps are required as follows:
Surface of all exposed concrete in basin shall conform in slope, grade, color, finish, and scoring to existing or proposed curb and walk adjacent to the basin.
General Notes:
T = 6 inches if H is 8 feet or less
T = 8 inches if H exceeds 8 feet
If H is 3.5 feet or less, no steps are required.
If H is more than 3.5 feet, but no more than 4 feet, install 1 step 12 inches above floor of basin If H is more than 4 feet, isntall steps 12 inches apart, with the top step 6 inches below the suface of the basin and 12 inches above the floor.
All steps shall be 6 to 7 inches from the wall.
3/4 inch galvanized steel or polypropylene plastic (Caltrans D72). -
-
-
-
-
-
-
Catch basin details shown are for cast-in-place and/or when not included on the Engineer's List of approved items.
-
DRAFT MARCH 2025
TYPE I CATCH BASIN
FILE NO:
STD - 403
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
SECTION A-A
APPROVED TYPE I CATCH BASINS
See Engineer's approved list
NOTES:
1. 2.
3. 4.
5. Concrete shall have a compressive
strength of 4000 psi in 28 days.
Grate and nosing angle shall be hot
dipped galvanized after fabrication
per ASTM A-123
Grate frames shall be installed tight
against gutter flowline
Catch basin box and grate shall be
constructed to withstand H20
loading.
Install label per City STD-409.
ONLY TO BE USED WHERE SPECIFICALLY APPROVED BY VARIANCE 6" MIN. 3/4" DRAIN ROCK
INSTALLED AGAINST
UNDISTURBED EARTH
6" MIN.
5" MIN.
30"
SEAL JOINT
WITH GROUT
SECTION B-B
TOP OF CURB
GUTTER FLOW LINE
6"
8"
48"
PLAN
A
A
LIP OF GUTTER
BACK OF CURB
BICYCLE PROOF GRATE
FACE OF CURB
B
6"
24"
B
48"
48"
24"
TOP TO BE PRECAST OR POURED
IN PLACE USING FIBERGLASS
INLET LINER.
CONCRETE COLLAR
REQUIRED PER STD-410
DRAFT MARCH 2025
STORM DRAIN GALLERY
FILE NO:
STD - 404
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
TYPICAL SECTION INSTALLED
APPROVED STORMD RAIN GALLERY FORM
See Engineer's approved list
NOTES:
1. 2.
3. Nosing assembly shall be hot dipped
galvanized after fabrication per ASTM A-123.
Concrete shall be class A.
Install label per City STD-409
ISOMETRIC VIEW
4'
4'
6' OR 12'
GALLERY
DEPRESS GUTTER
FLOWLINE (BOTH
SIDES)
BLOCKOUT OPENING IN
CATCH BASIN TO DRAIN
GALLERY
PRECAST CATCH BASIN WITH GALLERY
(RIGHT OR LEFT). SEE STDS-402, 405 & 409
GUTTER
TOP OF CURB
8" MIN.
GUTTER
TOP OF CURB
ANCHORS
FIBERGLASS LINER
WOVEN WIRE REINFORCING
1-1/2" NOTCH
3-1/2"x3-1/2"x1/4"
ANGLE NOSING
8"
6"
5" MIN.
DRAFT MARCH 2025
PRECAST CATCH BASIN COVER
FILE NO:
STD - 405
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
APPROVED PRECAST CATCH BASIN COVERS
See Engineer's approved list
NOTES:
1. 2.
3. 4.
5. 6.
Concrete shall have a compressive strength
of 4000 PSI at 28 days
Nosing angle shall be galvanized in
accordance with ASTM specification A-123.
Exposed concrete surface shall have broom
finish.
Cast iron shall conform to ASTM 48-30.
Apply label per City STD-409.
Frame ring inside diameter to be 5/16" to
3/8" greater than lid ring outside diameter.
ISOMETRIC
Precast lid 26-3/4" X 2"
with cast iron lid ring.
SECTION A-A
ELEVATION
Cast iron
frame ring
3-1/2" X 2-1/2" X
1/4" Galv. steel
nose angle.
5" radius fillet
Gutter flow
line
Cast iron
frame ring
See note 6.
Cast iron lid
ring
2-5/8"
32"
24"
5"
16-1/2"
See
STD-402B
5"
48"
A
A
Non traffic-cast iron lid
25-1/2". See STD-402B
See STD-402B
DRAFT MARCH 2025
3" SIDEWALK DRAIN
FILE NO:
STD - 406A
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
1. 2.
3. 4.
5. 6.
Wire mesh shall be full width of sidewalk minus 2".
Length of wire mesh shall, at a minimum, equal the
width and be centered over the pipe.
On-site drainage and location of curb outlets shall be
by owner to the satisfaction of the City Engineer.
Drain pipe shall be installed so that the top of pipe is 2-1/2" (min.) below finished grade at back of sidewalk.
Sidewalk shall be removed to the nearest scoremark.
If sidewalk and gutter are not contiguous, curb may be
cored or curb and gutter removed and replaced a
minimum of one foot on each side of the drain pipe.
Dowel new gutter to existing curb and gutter with (2)
12" #4 rebars, place one dowel in curb and one in
gutter pan using epoxy.
If sidewalk and gutter are contiguous, pour monolithic
with wire fabric extending into curb.
Score mark
SECTION B-B
(for one 3" pipe)
2-1/2"
min.
SECTION A-A
Gutter flow line
4" x 4" 10/10
woven wire mesh.
See note 6.
PLAN
4" x 4" 10/10
woven wire mesh.
See note 1.
3" SCH. 40 PVC
A
A
B
B
GUTTER
CURB
SIDEWALK (VARIES)
PER STD-230
SIDEWALK DRAIN PRIVATELY OWNED
AND MAINTAINED
DRAFT MARCH 2025
3" X 12-1/2" CAST IRON
SIDEWALK DRAIN
FILE NO:
STD - 406B
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
1. 2.
3. 4.
5. 6.
Wire mesh shall be full width of sidewalk minus 2".
Length of wire mesh shall, at a minimum, equal the
width and be centered over the pipe.
On-site drainage and location of curb outlets shall be
by owner to the satisfaction of the City Engineer.
Drain pipe shall be installed so that the top of pipe is 2-1/2" (min.) below finished grade at back of sidewalk.
Sidewalk shall be removed to the nearest scoremark.
If sidewalk and gutter are not contiguous, curb may be
cored or curb and gutter removed and replaced a
minimum of one foot on each side of the drain pipe.
Dowel new gutter to existing curb and gutter with (2)
12" #4 rebars, place one dowel in curb and one in
gutter pan using epoxy.
If sidewalk and gutter are contiguous, pour monolithic
with wire fabric extending into curb.
3" x 12-1/2" cast
iron drain
SECTION B-B
2-1/2"
min.
SECTION A-A
Flow line of pipe set
at gutter flow line
4" x 4" 10/10
woven wire mesh.
See note 6.
PLAN
4" x 4" 10/10
woven wire mesh.
See note 1.
3" x 12-1/2"
cast iron drain
A
A
B
B
GUTTER
CURB
SIDEWALK (VARIES)
PER STD-230
SIDEWALK DRAIN PRIVATELY OWNED
AND MAINTAINED
24"
3"
CAST IRON SIDEWALK DRAIN
See Engineer's Approved List
DRAFT MARCH 2025
TRENCH DRAIN
AND GRATE
FILE NO:
STD - 406C
CITY OF SANTA ROSA
Scale: NONE
DRAFT MARCH 2025
DWN: EDS
CHK:
APPROVED:
SECTION A-A
ISOMETRIC VIEW
3"
12" MIN.
6"
1"
14" x 6"
trench pan
lock bar
penta-head
security bolt
new concrete
slab
steel
anchor
LIP OF
GUTTER
GUTTER
FLOW LINE
BACK OF
CURB
CURB FACE
DECORATIVE
TRENCH GRATE
A
A
SIDEWALK
LOOSE ROCK RIP-RAP
STORM DRAIN OUTLET
FILE NO:
STD - 407A
NOTES:
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
1. 2.
CMP shall conform with Section 66-3
of the Standard Specifications.
HDPE pipe shall conform with Section
64 of the Standard Specification for
type S pipe.
SECTION A-A
LOOSE ROCK
RIP-RAP COLLAR
WITH 4" EARTH
COVERING TO
FILL VOIDS
STORM DRAIN OUTLET
ELEVATION
SLOPE PROTECTION
SLOPE
PROTECTION
TOP OF BANK
2' EACH SIDE OF
PIPE MINIMUM
DITCH FLOWLINE
Y
PIPE DIAMETER + 4 FT
MINIMUM WIDTH
18" MINIMUM
A
A
18" THICK LOOSE ROCK
COLLAR W/ 4" EARTH
COVER
CUT PIPE SLOPE TO
CONFORM WITH
DITCH SLIDE SLOPE
DITCH FLOW LINE
18"
MIN.
WHEN D < 24", Y=2'
WHEN D > 24", Y=1'
D + Y +2'
RCP
2'
Y
D
(2) #4 BARS
CONCRETE COLLAR
FOR DISSIMILAR
MATERIALS
12" MIN.
HDPE, RCP
OR CIPP
6" MIN.
/INLET
DRAFT MARCH 2025
LOOSE ROCK RIP-RAP
STORM DRAIN OUTLET
FILE NO:
STD - 407B
ROCK SLOPE PROTECTION
MATERIALS
Rocks shall be angular and well graded from an average diameter of four(4) inches to an average diameter of fifteen (15) inches with approximately fifty (50) percent by weight smaller than nine (9) inches in average diameter. Not more than ten (10) percent of the rock rip rap by weight shall be less than four (4) inches average diameter. Not more than ten (10) percent of the rock riprap by weight shall be greater than fifteen (15) inches in average diameter and none shall exceed an average diameter of twenty 20" inches.
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
SLOPE PROTECTION
STORM DRAIN INLET
SECTION A-A
STORM DRAIN INLET
PLAN VIEW
/INLET
EDGE OF ASPHALT
EXISTING DRAINAGE
CULVERT PER
COUNTY STD-820
DRIVEWAY FOR
UNIMPROVED STREET
PER STD-252
18" THICK LOOSE ROCK
COLLAR W/ 4" EARTH
COVER
2'
DRIVEWAY
DRAINAGE CULVERT
A
A
DRAFT MARCH 2025
PRECAST SIDE OPENING
FIELD DRAIN
FILE NO:
STD - 408
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
ISOMETRIC VIEW
PRECAST SIDE OPENING FIELD DRAIN
See Engineer's approved list
NOTES:
1. 2.
Field drain box shall be constructed
to withstand H20 loading.
Concrete shall have a compressive
strength of 4000 psi in 28 days
SECTION A-A
GROUT ALL VOIDS
BETWEEN PIPE AND
BOX
24"
SQUARE
(MINIMUM)
5" MIN.
1/4" GALVANIZED
CHECKER PLATE
COVER
SECURE WITH ANCHOR BOLTS
IN EACH CORNER
CONCRETE
COLLAR PER
STD-410
SIDE OPENINGS AS
NEEDED
SET TO FLOWLINE OF DIT
9"
MIN.
20"
MIN.
A
A
DRAFT MARCH 2025
STORM DRAIN LABELS
FILE NO:
STD - 409
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
APPROVED STORM DRAIN LABELS
See Engineer's approved list
NOTES:
1. 2.
3. Affix decal to center of catch basin lid
cover ONLY if catch basin is not part of the
sidewalk and cover is not cast iron.
If the catch basin lid cover is cast iron AND
the catch basin is not part of the sidewalk,
affix label in this location, oriented to be
read from the street aligned with the top
of curb.
Affix label on the curb face right of the
catch basin if catch basin is part of the
sidewalk. The left side may be used if the
right side curb is damaged or painted.
SEE NOTE 1
2" - 3"
SEE NOTE 2
SEE NOTE 3
2" - 3"
1" - 2"
5"
DRAFT MARCH 2025
REINFORCED CONCRETE
PIPE COLLAR
FILE NO:
STD - 410
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
SECTION A-A
PLAN
A
A
#4 REBARS AT 12"
CENTERS
#4 REBARS EQUALLY
SPACED
I.D.
2" (TYP)
I.D./4 (6" MIN)
PIPE O.D.
6"
6"
6"
6"
O.D. + 12"
O.D. + 12"
MIN 3000 PSI
@ 28 DAYS
CONCRETE
2" MIN CLEARANCE BETWEEN
OUTSIDE OF PIPE AND STEEL
DRAFT MARCH 2025
REINFORCED CONCRETE
STUB CAP
FILE NO:
STD - 411
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
SECTION A-A
PLAN
A
A
#4 REBARS AT 12"
CENTERS
#4 REBARS
EQUALLY SPACED
2" (TYP)
I.D./4 (6" MIN)
PIPE O.D.
6"
6"
6"
6"
O.D. + 12"
O.D. + 12"
MIN 3000 PSI
@ 28 DAYS
CONCRETE
2" MIN CLEARANCE BETWEEN
OUTSIDE OF PIPE AND STEEL
NOTES:
1. All reinforced concrete stub caps to be
inspected by City during construction
and before being covered.
PLYWOOD TO BE CUT TO INSIDE
DIAMETER TO SUPPORT CONCRETE
WORK AND TO BE REMOVED BEFORE
CCTV AND CITY ACCEPTANCE
#4 REBAR ONLY LOCATED AS
OUTER SET OF REBAR FROM
END OF PIPE
#4 REBAR ONLY LOCATED AS
OUTER SET OF REBAR FROM
END OF PIPE
DRAFT MARCH 2025
CONCRETE BEDDING CAP
FILE NO:
STD - 412
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
B
#4 REBARS @ 12"
TRANVERSE STEEL
NOTES:
1. 2.
3. 4.
All concrete for concrete bedding cap shall be Claass V concrete.
Concrete bedding cap required when a storm drain pipe encroaches in a roadway structural section or is less than three (3) feet below finish grade.
Use reinforcing steel when designated on the plans.
Unless otherwise specified, concrete bedding cap shall be paid for as part of the construction of pipe sewer or conduits.
6"
MIN.
6"
MIN.
CONCRETE
BEDDING MATERIAL
PER CITY STD-215
B/4 OR 4" MIN.
B/4 OR 4" MIN.
B/2
DRAFT MARCH 2025
STREET BIORETENTION
BULB-OUT, MID-BLOCK,
CORNER CROSSING
FILE NO:
STD - 413
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
NOTES:
1. This standard detail assumes gradual longitudinal and cross slopes of the roadway. Steeper slopes in either direction will impact conveyance and elevation differences between the facility and adjacent roadway , curb, and sidewalk surfaces.
Retrofit projects will face greater constraints than new construction. Site specific design is critical to avoid grade conflicts and maximizing ponding area. Grading plans that provide spot elevations across the entire facility and along adjacent surfaces are necessary.
REMOVE AND REPLACE EXISTING CURB
& GUTTER WITH RAISED DEEP CURB
LENGTH OF FACILITY
SIDEWALK
2" DROP TO
COBBLE
SEE NOTE 1
CURB CUT
INLET, SEE
STD-414
BIORETENTION
AREA
CURB CUT
OUTLET, SEE
STD-414
CURB CUT OUTLET,
SEE STD-414
CURB AND GUTTER
TO PUBLIC STORM
DRAIN SYSTEM
page 1 of 2
PLAN VIEW
BIORETENTION
AREA
HIGH-FLOW
BYPASS INLET
A
A
SECTION A-A
EDGE OF GUTTER
GUTTER PAN
2" DROP TO
COBBLE
BIORETENTION
AREA
BIORETENTION
AREA
HIGH-FLOW
BYPASS INLET
GUTTER PAN
DRAFT MARCH 2025
STREET BIORETENTION
BULB-OUT, MID-BLOCK,
CORNER CROSSING
FILE NO:
STD - 413
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
NOTES CONTINUED:
2. 3.
4. For the treatment of sidewalk runoff, a trench grate may be installed at the edge of the sidewalk transition to the curb ramp, as needed. The trench grate shall be Americans with Disabilities Act (ADA) compliant and heel proof.
Curb cut inlets to be located as governed by the grading design so as to prevent flows being concentrated toward the ramp to gutter transition location.
The number of curb cut inlets needed shall be governed by the inlet capacity and flooded width calculations presented in the Drainage Report.
page 2 of 2
PLAN VIEW
BIORETENTION
AREA
CURB CUT INLET,
SEE STD-414
TO PUBLIC STORM
DRAIN SYSTEM
HIGH-FLOW
BYPASS INLET
EDGE OF GUTTER
BIORETENTION
AREA
CURB AND GUTTER
CURB CUT INLET,
TYPICAL SEE
STD-414
CURB RAMP PER
CALTRANS
STANDARD A88A
SIDEWALK
SIDEWALK
PROPERTY
LINE
CROSSWALK
CROSSWALK
PARKING
PARKING
0" CURB
HEIGHT
FULL HEIGHT
CURB
SEE NOTE 2
DRAFT MARCH 2025
CURB CUT INLET/OUTLET
FOR PLANTERS
FILE NO:
STD - 414
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
NOTES:
1. 2.
3. 4.
5. For use with stormwater facilities with flat bottoms.
Provide spot elevations on plans for finished grade, gutter inlet, top of curb, lip of gutter, etc.
Curb and wall details may be modified by Civil and
Geotechnical Engineer subject to approval by the City
Engineer.
Curb height may be reduced to 4" where adjacent to a
sidewalk.
If rock slope protection is used, calculations for the sizing based on flow velocities is required in the drainage report and Stormwater Low-impact Development Report, as
applicable.
DEPRESS GUTTER
2" AT OPENING,
GUTTER INLET
ELEVATION
DEPRESS GUTTER
2" AT OPENING,
GUTTER INLET
ELEVATION
4" THICK CONCRETE
SPLASH PAD
R=6"
CURB AND
GUTTER
PERSPECTIVE VIEW
PLAN VIEW
6"
8"
6"
CURB
12"-18"
1'-6"
4'-6"
12"
CURB
A
A
SECTION A-A
STREET
6"
6"
6"
1'-6"
4"-6" MIN.
1'-6"
R=3/4" TYP.
DEPRESS GUTTER
2" AT OPENING
R=3/4" TYP.
4" THICK CONCRETE
SPLASH PAD AT FACILITY
FINISHED ELEVATION, OR
ROCK SLOPE PROTECTION,
SEE NOTE 5.
FINISHED
ELEVATION
DRAFT MARCH 2025
STORM DRAIN UNDER
CURB OR PLANTER
FILE NO:
STD - 415
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
PLAN VIEW
PARKING/BIKE
LANE
SECTION B-B
TRAVEL LANE
CURB AND GUTTER
PLANTER STRIP
SIDEWALK
PUBILIC UTILITY
EASEMENT
CORRIDOR
13'
LID BMP
REVERSE CURB DRAIN OR
TRENCH DRAIN W/ HEEL
PROOF GRATE. SEE NOTE 2.
DRAINAGE INLET.
SEE NOTE 3.
REVERSE SIDEWALK
SLOPE. SEE NOTE 1.
2%
MAX
PUBLIC STORM
DRAIN MAIN
ROADWAY
PLANTER
STRIP
SDWLK
PUE
CORRIDOR
LID BMP
2% MAX
PUBLIC STORM DRAIN
SEE NOTE 2
SEE NOTE 3
ROADWAY
PLANTER
STRIP
SDWLK
PUE
CORRIDOR
LID BMP
2% MAX
PUBLIC STORM DRAIN
SEE NOTE 1
DRAINAGE INLET
page 1 of 2
JOINT TRENCH
JOINT TRENCH
A
A
B
B
SECTION A-A
DRAFT MARCH 2025
STORM DRAIN UNDER
CURB OR PLANTER
FILE NO:
STD - 415
CITY OF SANTA ROSA
Scale: NONE
DWN: EDS
CHK:
APPROVED:
NOTES:
1. 2.
3. 4.
5. 6.
7. 8.
9. 10.
For the treatment of replaced or proposed sidewalk behind the planter strip or contiguous sidewalk, the sidewalk may be reversed and runoff graded to or conveyed to a LID BMP. This option does not treat the roadway.
Reverse curb drain per STD-406A/B or trench drain with a heel proof grate.
Sidewalk runoff captured within the planter strip then conveyed to the LID BMP via SCH. 40 PVC.
Only sidewalk treatment is provided
No rebar or reinforcement shall be placed over public storm drain facilities.
No improvements within the sidewalk, planter strip, or right-of-way shall intrude within the pipe or pipe bedding.
No portion of any structure or LID BMP shall extend within, over, under, or upon any public utility easement unless otherwise approved by the City Engineer.
Utility services and laterals may run through a public utility easement perpendicularly, but private utilities may not run longitudinally within the PUE.
A curb cut may be added to treat the roadway.
Prior to utility crossings and connections over or under the existing public storm drain, the contractor shall pothole and ensure no conflicts occur with the existing storm drain facilities.
The contractor shall be responsible for repairing, damage, or deterioration occurring to the existing public storm drain as a direct result of construction activity related to the installation of the improvements.
page 2 of 2
DRAFT MARCH 2025
City of Santa Rosa | Public Storm Drain Standards | [Date] 48
III. PUBLIC STORM DRAIN CONSTRUCTION STANDARD SPECIFICATIONS
CONTENTS
Section 64 Plastic Pipe
Section 65 Reinforced Concrete Pipe
Section 70 Miscellaneous Drainage Structures
Section 79 Closed Circuit Television (CCTV) Inspection of Storm Drains
City of Santa Rosa | Public Storm Drain Standards | [Date] 49
SECTION 64. PLASTIC PIPE
64-1.01 Description
Plastic pipe for use in public storm drain systems shall be 15” through 48” diameter Type S, smooth interior wall, corrugated exterior wall, high density polyethylene pipe (HDPE) as specified in AASHTO designation M294 or high-performance polypropylene (HPPP) as specified in ASTM F2881 or AASHTO M330. HDPE and HPPP compounds used in the manufacture of plastic pipe shall be per the Standard Specifications. The HDPE and HPPP pipe walls must be free of cracks, holes, voids, blisters, foreign inclusions, scratches deeper than 10% of the wall thickness, or other defects visible to the naked eye or affecting the pipe wall integrity. The residue from the ignition of HDPE or HPPP compounds must not exceed 30 percent as determined under ASTM D2584 except the muffle furnace temperature must be 840 ± 45 degrees Fahrenheit.
64-1.02 General
See Section 64-1.02A of the Standard Specifications
4 64-1.02E Couplings and Fittings
Pipe and fittings shall be joined with a bell-and-spigot joint meeting AASHTO M252, AASHTO M294, or MP7. The joint shall be soil tight elastomeric o-ring gaskets meeting the requirements of ASTM F477. HPPP shall have bell-and spigot joints per ASTM D3212. Gaskets shall be supplied by the pipe manufacturer and covered with a removable wrap to ensure the gasket is free from debris. A joint lubricant supplied by the manufacturer shall be used on gasket and bell during assembly. The spigot shall be pushed into the bell to the “home line” on the pipe. The method of joining pipes and fittings shall be as recommended by the pipe manufacturer.
64-1.03B Excavation and Backfill
Excavation and backfill shall be as shown on City Standard 215 and the following provisions.
The space between the pipe and trench wall shall be wider than the compaction equipment used in the pipe zone, regardless of the dimensions shown on the City Standard 215 unless self- compacting backfill material is used.
Pipe bedding will be placed in 6" (maximum) lifts to 6" above the top of pipe with each lift hand or mechanically tamped. The final lift may be compacted with a plate-type vibrating compactor.
During construction, heavy equipment vehicle loads over the pipe shall be avoided or additional cover shall be placed at vehicle crossings.
City of Santa Rosa | Public Storm Drain Standards | [Date] 50
64-1.07 Laying Pipe
Plastic storm drain pipe shall be installed in accordance with the Standard Specifications, generally accepted practice and on the alignment and grade as shown on the plans. When long radius curves are permitted, adjustments in horizontal alignment will be achieved by using 3° mitered couplings with a minimum of 10 feet between each mitered coupling and not by bending of the pipe or deflecting joints.
Pipe shall be centered in the trench.
Unless otherwise specifically permitted by the Engineer, all pipe shall be laid upgrade.
Where ground water or surface drainage occurs, pumping shall continue until backfilling has progressed to a sufficient height to prevent flotation of the pipe.
64-1.08 Video Inspection of Plastic Storm Drain Pipe
Video inspection of plastic storm drain pipe shall be in accordance with City Standard 79.
64-1.10 Mandrel Testing
If the video inspection of the pipe indicates the probability of deflection or obstruction in the pipe, mandrel testing shall be required by the engineer. The mandrel shall be able to detect a deflection of 7.6% or greater of the inside diameter of the pipe. All defects indicated in the video shall be corrected; the pipe shall pass a mandrel test and an additional video inspection before acceptance.
City of Santa Rosa | Public Storm Drain Standards | [Date] 51
SECTION 65. REINFORCED CONCRETE PIPE
65-1.01 Description
Reinforced concrete pipe shall be installed on the alignment and grade as shown on the plans and in accordance with Section 65 of the City of Santa Rosa Construction Specifications and as directed by the Engineer. Reinforced concrete pipe to be installed shall be the size and class as shown on the plans, and shall conform to the provisions of ASTM C76.
65-1.02 Materials
All concrete pipe shall conform to the provisions of Section 65-21.02 of the Standard Specifications prior to shipment from the manufacturer.
65-1.03 Earthwork
Excavation and backfill shall conform to the City of Santa Rosa Construction Specifications. Backfill shall be in accordance with City Std. 215 and as shown on the plans.
If, during excavation for any culvert or structure, material is encountered which is unsuitable as a foundation for such culvert or structure, such unsuitable material shall be removed to a depth as required by the Engineer and the resulting space shall be refilled with approved material.
Trenching operations shall be conducted in such a manner as not to disturb the existing curb and gutter and existing utilities.
Trenching operations for pipelines and structures shall be conducted in such a manner to minimize damage to existing tree roots. Hand digging shall be used where necessary to protect tree roots. Where tree roots are encountered, root pruning shall be accomplished by use of sharp tools appropriate for the size of root to be cut. Each cut shall be clean with no torn bark or splintered wood remaining on the tree. All tree work shall be performed by a certified arborist from the list approved by the City.
All raised pavement markers, street striping, chatter bars or any other traffic markings disturbed during work shall be replaced in kind by the Contractor to the satisfaction of the Engineer.
65 -1.07 Laying Culvert Pipe
Unless otherwise specifically permitted by the Engineer, all pipe shall be laid upgrade. No pipe shall be laid which is cracked, checked, spalled, or damaged and which, in the opinion of the Engineer, is unsuitable for use.
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Pipe joints shall be sealed with grout or by use of a rubber gasket. A joint lubricant recommended by the pipe manufacturer shall be used on gasket sealed pipe. All excess grout shall be removed from inside of grout sealed pipes.
Proper implements, tools, and facilities satisfactory to the Engineer shall be provided and used by the contractor for the safe and efficient execution of the work. All pipe, fittings, and accessories shall be carefully lowered into the trench by means of derrick, ropes, or other suitable equipment in such a manner as to prevent damage to pipe and fittings. Under no circumstances shall pipe or accessories be dropped or dumped into the trench. The pipes and accessories shall be inspected for visible defects prior to lowering into the trench. Any visibly-defective or unsound pipe shall be replaced.
The line and grade of existing utilities designated to remain shall not be altered. Any leakage caused in existing utilities by reason of the Contractor’s operations shall be immediately repaired at the Contractor’s expense.
Existing water lines shall be supported in place maintaining service during construction.
The Contractor shall be responsible for any damage to the water lines during construction and any damage resulting from improper backfilling techniques. Water services shall be relocated where encountered during construction and as shown on the plans.
Existing sewer lines shall be supported in place maintaining service during construction.
The Contractor shall be responsible for any damage to the sewer lines during construction and any damage resulting from improper backfilling techniques.
65-1.08 Television Inspection of Reinforced Concrete Storm Drain Pipe
Television inspection of reinforced concrete pipe shall be in accordance with City Standard 79.
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SECTION 70. MISCELLANEOUS DRAINAGE STRUCTURES
70-1.02 Structures
Storm drain manholes shall be standard 48" diameter precast concrete manholes or 60" diameter precast concrete manhole at the locations shown on the plans and in accordance with City Standard Details.
Concrete for manhole bases shall be portland cement concrete conforming to the requirements of Section 90 of the City Design and Construction Standards and shall be poured full thickness against the sides of the manhole excavation or shall be formed.
Manhole barrels and taper sections shall be precast concrete sections using Type II portland cement complying with ASTM Designation: C150. The barrel and taper sections shall be constructed in accordance with the applicable provisions of ASTM Designation: C478.
Top of manhole frames and covers shall be set accurately to the final finished grade in paved streets and to the elevation shown in unimproved areas.
Concrete for catch basins shall be portland cement concrete conforming to the requirements of City Design and Construction Standards.
Catch basin covers shall be concrete with cast iron frame and lid rings per City Standard. 405.
“No dumping” decals shall be applied to catch basins per City Standard. 409.
In lieu of the inspection of reinforcing steel and upon request, the Contractor shall furnish the Engineer with a certificate from the supplier of the reinforcing steel stating that the steel delivered complies with the requirements of Section 52-1.02 of the Standard Specifications.
Bar reinforcing shall conform to and be placed in accordance with Section 52 of the Standard Specifications.
Connections to existing storm drain structures shall be made with care to avoid unnecessary damage to any existing curb and gutter or sidewalk. Any damaged section shall be removed and replaced in accordance with City Standards and as approved by the Engineer. Pipe connections to the existing structures shall be sealed with cement mortar.
Drop inlets and grates shall be bicycle-safe and designed for H20 loading. Frame and grate shall be hot-dipped galvanized after fabrication.
70-1.135 Mortar
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70-1.135A Description
Mortar shall consist of a mixture of Type II portland cement complying with ASTM C150, sand, and water. Sand for mortar shall be clean, dry, well-graded sand, free of organic or other deleterious matter, silt or other objectionable material.
Mortar shall conform to the requirements of Section 65-2.02E of the Standard Specifications.
70-1.135B Admixtures
No admixtures will be permitted unless authorized by the Engineer.
70-1.135C Curing
After placing, all surface of mortar shall be cured by the water method in accordance with Section 90-1.03B, "Curing Concrete" of the Standard Specifications, for a period of not less than 3 days.
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SECTION 79. CLOSED CIRCUIT TELEVISION (CCTV) INSPECTION OF STORM DRAINS
79-1.01 Description
Television inspection of all new and modified storm drain pipes and structures is required.
The contractor shall hire an independent pipe video inspection service to perform the inspection. The camera used shall be self-propelled or pulled, be able to pan and tilt and shall be equipped with high-intensity lights. A digital video compatible with and uploaded to ITpipes shall be produced along with a printed log of the inspection and delivered to the Engineer. The pipe inspection service shall be pre-approved by the City. All Closed Circuit Television (CCTV) inspections shall conform to current National Association of Sewer Service Companies (NASSCO) Pipeline Assessment Certification Program (PACP) standards. Additionally, the digital CCTV data shall meet the following requirements in order to be compatible with ITpipes:
1. NASSCO v7 PACP data exchange export file for CCTV and containing the complete project.
2. Each observation is required to have at minimum one snapshot associated showing the defect and each snapshot shall be referenced inside the PACP file.
3. Video shall be inside an h.264 video format and referenced inside the PACP file.
4. The video titler/overlay display shall have an initial start screen, inspection
Camera movement means, rotational and panning abilities, and pace shall meet NASSCO PACP standards.
Video and picture quality shall be a minimum of HD-1080p.
All cleaning water and debris shall be captured, removed and properly disposed. Cleaning water will not be allowed to discharge to the storm drain system.
The contractor is responsible for all stuck, broken or lost equipment and shall bear all necessary cost to retrieve said equipment including dig ups.
All work performed must meet quality and clarity standards set by the City of Santa Rosa and are subject to Public Works review. A pan and tilt color camera will be used for all video inspections of storm drains within the jurisdiction of the City of Santa Rosa.
The following conditions shall exist prior to the television inspection:
1. All storm drain pipes shall be installed, grouted, backfilled to 5 feet over the top of the pipe or to subgrade, and compacted;
2. Conduits or pipelines for all underground utilities (sewer, water, cable television,
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telephone, electrical, gas, street light) that cross storm drain trench shall be installed;
3. The bases of all structures shall be in place and grouted;
4. The system shall be cleaned and all debris removed;
5. Street shall be unpaved;
When the above work has been completed, the contractor shall notify the Engineer 48 hours in advance of the date for television inspection. Immediately before inspection the system shall be flushed with clean water. During this inspection, the contractor or authorized representative shall be present to observe the video as provided by the television camera.
The results of all observations will be logged and whatever data may be required for record purposes shall be prepared. Measurement for location of features along the pipe alignment shall be at ground level by means of a counting. The counting meter shall be mounted on the CCTV reel power winding assembly. The meter shall be equipped with a local mechanical readout for use at the rear of the television vehicle and an electronic counter which is connected to the data view system for display on the video tape. Marking on cable, or the like, which would require interpolation for depth of manhole will not be allowed. The counting meter shall accurately record the distance in feet, which the video cable has traveled. The measurement will be accurate to three-tenths (0.3) of a foot per ten (10) feet of inspected storm drain reach length.
At the beginning of each run of storm drain pipe the video shall display:
1. The project name;
2. Date;
3. Company performing the inspection;
4. Run number (unique designation for each section of pipe);
5. Street name (if applicable);
6. Pipe size;
7. Pipe material;
8. Structure numbers (as labeled on the plans) at each end of the pipe;
9. Direction of the camera;
10. Type of structure.
The video shall display the following information continuously during the run:
1. The camera’s location via a continuously updated footage counter measuring the distance from point of entry;
2. Project name;
3. Structure numbers (as shown on the plans) at each end of the run;
4. Run number.
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The camera shall stop at all structures, connections or defects (sags, bad joints, etc.) for a period of at least 10 seconds and be noted on the log sheet. The camera will be panned or tilted toward the connection or defect so that any portion of the connection or defect that is visible from within the pipe or structure can be completely inspected.
A printed record shall be made for each pipe run and shall clearly show the:
1. Run number;
2. Structure number at each end of the run;
3. Direction of camera travel;
4. Location and description of each defect discovered by the camera;
5. Line size;
6. Length of run;
7. Structure depths;
8. Location of blind connections.
The video inspection data shall be uploaded to ITpipes and report shall be delivered to the Engineer and become the property of the City of Santa Rosa. The inspection report shall meet NASSCO PACP standards.
The following video observations shall be considered defects in the construction of the storm drain system and will require corrections prior to acceptance:
A.Off grade - 0.08' or more deviation from grade;
B.Joint separations;
C.Offset joints;
D.Cracked or damaged pipe or evidence of the presence of an external object bearing upon the pipe (rock, root, etc.);
E.Debris or other foreign objects;
F.Pipe deflections greater than 7.5% of base diameter, measured inside the pipe;
G.Other obvious deficiencies when compared to approved Plans and Specifications, these Standards and City Design and Construction Standards.
The contractor will be notified in writing of any deficiencies revealed by the television inspection that will require repair, following which the contractor shall excavate and make the necessary repairs and request a television re-inspection. Television re-inspection shall be at the contractor’s expense.
Any subsequent televising of the lines, if deemed necessary by the City, shall be
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completed at the City’s expense. Any defects found prior to or during the warranty period shall be corrected by the contractor.
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IV. ENGINEER’S LIST OF APPROVED ITEMS FOR CONSTRUCTION
Engineer’s list of approved Items can be found at:
www.srcity.org/2321/Design-Construction-Standards