San Marcos City Council
December 9, 2025

ATTACHMENT G
UDSP EIR 2025 ADDENDUM - APPENDIX G -
SWQMP

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025

TABLE OF CONTENTS

Acronym Sheet
PDP SWQMP Preparer's Certification Page
PDP SWQMP Project Owner's Certification Page
Submittal Record
Project Vicinity Map
FORM I-1 Applicability of Storm Water BMP Requirements
FORM I-2 Project Type Determination Checklist (Standard Project or PDP) FORM I-3B Site Information Checklist for PDPs
FORM I-4 Source Control BMP Checklist for All Development Projects FORM I-5 Site Design BMP Checklist for All Development Projects FORM I-6 Summary of PDP Structural BMPs
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1a: DMA Exhibit
Attachment 1b: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment 1c: Harvest and Use Feasibility Screening (when applicable) Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable) Attachment 1e: Pollutant Control BMP Design Worksheets / Calculations Attachment 2: Backup for PDP Hydromodification Control Measures Attachment 2a: Hydromodification Management Exhibit
Attachment 2b: Management of Critical Coarse Sediment Yield Areas Attachment 2c: Geomorphic Assessment of Receiving Channels Attachment 2d: Flow Control Facility Design
Attachment 3: Structural BMP Maintenance Plan
Attachment 3a: B Structural BMP Maintenance Thresholds and Actions Attachment 3b: Draft Maintenance Agreement (when applicable) Attachment 4: Copy of Plan Sheets Showing Permanent Storm Water BMPs

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025

ACRONYMS

APN Assessor's Parcel Number
BMP Best Management Practice
HMP Hydromodification Management Plan
HSG Hydrologic Soil Group
MS4 Municipal Separate Storm Sewer System
N/A Not Applicable
NRCS Natural Resources Conservation Service
PDP Priority Development Project
PE Professional Engineer
SC Source Control
SD Site Design
SDRWQCB San Diego Regional Water Quality Control Board
SIC Standard Industrial Classification
SWQMP Storm Water Quality Management Plan

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025

PDP SWQMP PROJECT OWNER'S CERTIFICATION PAGE

Project Name: CUBESMART SELF STORAGE
Permit Application Number: CUP24-0005

PROJECT OWNER'S CERTIFICATION

This PDP SWQMP has been prepared for CARMEL ENTERPRISE, LLC by STEVENS CRESTO ENGINEERS. The PDP SWQMP is intended to comply with the PDP requirements of the CITY OF SAN MARCOS BMP Design Manual, which is a design manual for compliance with local CITY OF SAN MARCOS and regional MS4 Permit (California Regional Water Quality Control Board San Diego Region Order No. R9-2015-0100) requirements for storm water management.

The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this plan. Once the undersigned transfers its interests in the property, its successor-in- interest shall bear the aforementioned responsibility to implement the best management practices (BMPs) described within this plan, including ensuring on-going operation and maintenance of structural BMPs. A signed copy of this document shall be available on the subject property into perpetuity.

_________________________________________________________ Project Owner's Signature

__Gary Levitt, Manager______________________________________ Print Name

__Urban Villages San Marcos, LLC by: Noble Canyon, LLC, its Manager_ Company

__3/14/2025________________
Date

_________________________________________________________ Project Owner's Signature

_________________________________________________________ Project Owner's Signature

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025

SUBMITTAL RECORD

Use this Table to keep a record of submittals of this PDP SWQMP. Each time the PDP SWQMP is re- submitted, provide the date and status of the project. In column 4 summarize the changes that have been made or indicate if response to plancheck comments is included. When applicable, insert response to plancheck comments behind this page.

Submittal
Number
Date Project Status Summary of Changes
1 09/30/2024  Preliminary Design /
Planning/ CEQA
 Final Design
Initial Submittal
2 01/21/2025  Preliminary Design /
Planning/ CEQA
 Final Design
Response to comments
3 03/14/2025  Preliminary Design /
Planning/ CEQA
 Final Design
Response to comments

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025

PROJECT VICINITY MAP

Project Name: CUBESMART SELF STORAGE
Permit Application Number: CUP24-0005

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Applicability of Storm Water Best Management Practices (BMP) Requirements (Storm Water Intake Form for all Development Permit Applications) For detailed information please visit:
http://www.san-marcos.net/departments/development-services/stormwater/development-planning Form I-1
[March 15, 2016]
Project Identification
Project Name: CUBESMART SELF STORAGE
Description: Project proposes the development of a commercial self-storage facility.

Permit Application Number (if applicable): CUP24-0005 Date: 03/14/2025 Project Address: 337 East Carmel Street, San Marcos, CA 92078 Determination of Requirements
This form is required as part of the City’s application process. The purpose of this form is to identify potential land development planning storm water requirements that apply to development projects.

Development projects are defined as construction, rehabilitation, redevelopment, or reconstruction of any public or private projects. In addition, the identification of a development project, as it relates to storm water regulations, would truly apply to development and redevelopment activities that have the potential to contact storm water and contribute a source of pollutants, or reduce the natural absorption and infiltration abilities of the land.

To access the BMP Design Manual, Storm Water Quality Management Plan (SWQMP) templates, and other pertinent information related to this program please refer to:
http://www.san-marcos.net/departments/development-services/stormwater/development-planning

Please answer each of the following steps below, starting with Step 1 and progressing through each step until reaching "Stop".

Step Answer Progression
Step 1: Based on the above, Is the project a
"development project" (See definition above)?
See Section 1.3 of the BMP Design Manual for
further guidance if necessary.
 Yes Go to Step 2.
 No Permanent BMP requirements do not apply. No
SWQMP will be required. Provide brief discussion
below. STOP.

Discussion / justification if the project is not a "development project" (e.g., the project includes only interior remodels within an existing building):

Step 2: Is the project a Standard Project, Priority
Development Project (PDP), or exception to PDP
definitions?

To answer this item, complete Form I-2, Project
Type Determination. See Section 1.4 of the BMP
Design Manual in its entirety for guidance.

In addition to Section 1.4, please refer to the
City’s SWQMP Submittal Requirements form.

 Standard Project Only Standard Project requirements apply, including Standard Project SWQMP. STOP.
 PDP Standard and PDP requirements apply, including
PDP SWQMP. Go to Step 3 on the following page.
 Exception to PDP
definitions
Standard Project requirements apply, and any
additional requirements specific to the type of
project. Provide discussion and list any additional
requirements below. Prepare Standard Project
SWQMP. STOP.

Discussion / justification, and additional requirements for exceptions to PDP definitions, if applicable:

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-1 Page 2, Form Date: March 15, 2016
Step 3 (PDPs only). Please answer the list of questions in this section to determine if hydromodification requirements reply to the proposed PDP. Does the project:

Step 3a. Discharge storm water
runoff directly to the Pacific Ocean?
 Yes STOP. Hydromodification requirements do not apply.  No Continue to Step 3b.

Step 3b. Discharge storm water
runoff directly to an enclosed
embayment, not within protected
areas?
 Yes STOP. Hydromodification requirements do not apply.  No Continue to Step 3c.

Step 3c. Discharge storm water
runoff directly to a water storage
reservoir or lake, below spillway or
normal operating level?
 Yes STOP. Hydromodification requirements do not apply.  No Continue to Step 3d.

Step 3d. Discharge storm water
runoff directly to an area identified in
WMAA?
 Yes STOP. Hydromodification requirements do not apply.  No Hydromodification requirements apply to the project. Go to Step

4. Discussion / justification if hydromodification control requirements do not apply:

Step 4 (PDPs subject to
hydromodification control
requirements only). Does protection
of critical coarse sediment yield areas
apply based on review of WMAA
Potential Critical Coarse Sediment
Yield Area Map?
See Section 6.2 of the BMP Design
Manual for guidance.

 Yes Management measures required for protection of critical coarse sediment yield areas (Chapter 6.2).

Stop.
 No Management measures not required for protection of critical coarse sediment yield areas.

Provide brief discussion below.

Stop.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Project Type Determination Checklist Form I-2
[March 15, 2016]
Project Information
Project Name/Description: CUBESMART SELF STORAGE
Permit Application Number (if applicable): CUP24-0005 Date: 03/14/2025 Project Address: 337 East Carmel Street, San Marcos, CA 92078 Project Type Determination: Standard Project or Priority Development Project (PDP) The project is (select one):  New Development  Redevelopment The total proposed newly created or replaced impervious area is: 90,430 ft2 (2.08) acres Is the project in any of the following categories, (a) through (f)? Yes

No

(a) New development projects that create 10,000 square feet or more of impervious surfaces (collectively over the entire project site). This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land.

Yes

No

(b) Redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface (collectively over the entire project site on an existing site of 10,000 square feet or more of impervious surfaces). This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land.

Yes

No

(c) New and redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface (collectively over the entire project site), and support one or more of the following uses:
(i) Restaurants. This category is defined as a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification (SIC) code 5812). (ii) Hillside development projects. This category includes development on any natural slope that is twenty-five percent or greater.
(iii) Parking lots. This category is defined as a land area or facility for the temporary parking or storage of motor vehicles used personally, for business, or for commerce.
(iv) Streets, roads, highways, freeways, and driveways. This category is defined as any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-2 Page 2, Form Date: March 15, 2016
Yes

No

(d) New or redevelopment projects that create and/or replace 2,500 square feet or more of impervious surface (collectively over the entire project site), and discharging directly to an Environmentally Sensitive Area (ESA). “Discharging directly to” includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not commingled with flows from adjacent lands).

Note: ESAs are areas that include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Board and San Diego Water Board; State Water Quality Protected Areas; water bodies designated with the RARE beneficial use by the State Water Board and San Diego Water Board; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. See BMP Design Manual Section 1.4.2 for additional guidance.

Yes

No

(e) New development projects, or redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface, that support one or more of the following uses:
(i) Automotive repair shops. This category is defined as a facility that is categorized in any one of the following SIC codes: 5013, 5014, 5541, 7532- 7534, or 7536-7539.
(ii) Retail gasoline outlets (RGOs). This category includes RGOs that meet the following criteria: (a) 5,000 square feet or more or (b) a projected Average Daily Traffic (ADT) of 100 or more vehicles per day.

Yes

No

(f) New or redevelopment projects that result in the disturbance of one or more acres of land and are expected to generate pollutants post construction.

Note: See BMP Design Manual Section 1.4.2 for additional guidance.

Does the project meet the definition of one or more of the Priority Development Project categories (a) through (f) listed above?
 No – the project is not a Priority Development Project (Standard Project).  Yes – the project is a Priority Development Project (PDP).

The following is for redevelopment PDPs only:

The area of existing (pre-project) impervious area at the project site is: ________ ft2 (A) The total proposed newly created or replaced impervious area is ________ ft2 (B) Percent impervious surface created or replaced (B/A)*100: _______% The percent impervious surface created or replaced is (select one based on the above calculation):
 less than or equal to fifty percent (50%) – only new impervious areas are considered PDP OR
 greater than fifty percent (50%) – the entire project site is a PDP

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Site Information Checklist
For PDPs
Form I-3B (PDPs)
[March 15, 2016]
Project Summary Information
Project Name CUBESMART SELF STORAGE
Project Address 337 EAST CARMEL STREET
SAN MARCOS, CA 92078

Assessor's Parcel Number(s) (APN(s)) 220-201-90
Permit Application Number CUP24-0005
Project Hydrologic Unit Select One:
 Santa Margarita 902
 San Luis Rey 903
 Carlsbad 904
 San Dieguito 905
 Penasquitos 906
 San Diego 907
 Pueblo San Diego 908
 Sweetwater 909
 Otay 910
 Tijuana 911
Project Watershed
(Complete Hydrologic Unit, Area, and Subarea
Name with Numeric Identifier)
Richland 904.52
Parcel Area
(total area of Assessor's Parcel(s) associated
with the project)

2.71 Acres (117,989 Square Feet)
Area to be Disturbed by the Project
(Project Area)

2.90 Acres (126,255 Square Feet)
Project Proposed Impervious Area
(subset of Project Area)

2.08 Acres (90,430 Square Feet)
Project Proposed Pervious Area
(subset of Project Area)

0.82 Acres (35,825 Square Feet)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project.

This may be less than the Parcel Area.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 2 of 10, Form Date: March 15, 2016
Description of Existing Site Condition
Current Status of the Site (select all that apply):
 Existing development
 Previously graded but not built out
 Demolition completed without new construction
 Agricultural or other non-impervious use
 Vacant, undeveloped/natural

Description / Additional Information:

The project area is located north of Enterprise Street, east of Industrial Street, and west of Venture Street, and adjacent to Carmel Street. In the existing condition, CubeSmart Self Storage has a rough graded pad per GP21-00004.

Existing Land Cover Includes (select all that apply):
 Vegetative Cover
 Non-Vegetated Pervious Areas
 Impervious Areas

Description / Additional Information:

The site is currently a rough graded pad per GP21-00004.

Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
 NRCS Type A
 NRCS Type B
 NRCS Type C
 NRCS Type D
Type C soil is dominant throughout the site per USDA Web Soil Survey.

Approximate Depth to Groundwater (GW):
 GW Depth < 5 feet
 5 feet < GW Depth < 10 feet
 10 feet < GW Depth < 20 feet
 GW Depth > 20 feet
See Geotechnical Exploration, Inc. “Report of Update Geotechnical Investigation,” for Campus Pointe Affordable Housing Project, San Marcos, CA, dated January 20, 2021 for additional information.

Existing Natural Hydrologic Features (select all that apply):
 Watercourses
 Seeps
 Springs
 Wetlands
 None

Description / Additional Information:

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 3 of 10, Form Date: March 15, 2016
Description of Existing Site Drainage Patterns
How is storm water runoff conveyed from the site? At a minimum, this description should answer:
(1) whether existing drainage conveyance is natural or urban; (2) Is runoff from offsite conveyed through the site? if yes, quantify all offsite drainage areas, design flows, and locations where offsite flows enter the project site, and summarize how such flows are conveyed through the site;
(3)Provide details regarding existing project site drainage conveyance network, including any existing storm drains, concrete channels, swales, detention facilities, storm water treatment facilities, natural or constructed channels; and
(4) Identify all discharge locations from the existing project site along with a summary of conveyance system size and capacity for each of the discharge locations. Provide summary of the pre-project drainage areas and design flows to each of the existing runoff discharge locations.

Describe existing site drainage patterns:

In the existing condition, the site is composed of rough graded pads which drain into sediment basins constructed per GP21-00004. The sediment basins drain into an existing double 6’x5’ box culvert constructed per IP21-00005. Flow continues flowing through existing culverts at Carmel Street and State Route 78.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 4 of 10, Form Date: March 15, 2016
Description of Proposed Site Development
Project Description / Proposed Land Use and/or Activities:

CubeSmart Self Storage proposes the development of two new commercial self-storage buildings and improvements associated with development. This development would accommodate the relocation of an existing self-storage facility at 235 E. Carmel Street to 337 E. Carmel Street.

List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features):

Storage unit buildings, walkways and sidewalks, street improvements and driveways.

List/describe proposed pervious features of the project (e.g., landscape areas):

Landscape and self-mitigating (hydroseed) areas.

Does the project include grading and changes to site topography?  Yes
 No

Description / Additional Information:

The project includes fine grading associated with development.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 5 of 10, Form Date: March 15, 2016
Description of Proposed Site Drainage Patterns
Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)?
 Yes
 No

If yes, provide details regarding the proposed project site drainage conveyance network, including storm drains, concrete channels, swales, detention facilities, storm water treatment facilities, natural or constructed channels, and the method for conveying offsite flows through or around the proposed project site. Identify all discharge locations from the proposed project site along with a summary of the conveyance system size and capacity for each of the discharge locations. Provide a summary of pre- and post-project drainage areas and design flows to each of the runoff discharge locations. Reference the drainage study for detailed calculations.

Describe proposed site drainage patterns:

Runoff generated by the proposed project will be conveyed via a proposed private storm drain system into two proposed private underground detention systems (UD-1 & UD-2). A flow control/bypass structure downstream of each underground detention system will route the required DCV into a corresponding proposed private proprietary biofiltration system (PBF-1 & PBF-2). Runoff will then continue downstream via a proposed private storm drain system into an existing box culvert which flows under East Carmel Street and State Route 78.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 6 of 10, Form Date: March 15, 2016
Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply):
 On-site storm drain inlets
 Interior floor drains and elevator shaft sump pumps
 Interior parking garages
 Need for future indoor & structural pest control
 Landscape/Outdoor Pesticide Use
 Pools, spas, ponds, decorative fountains, and other water features  Food service
 Refuse areas
 Industrial processes
 Outdoor storage of equipment or materials
 Vehicle and Equipment Cleaning
 Vehicle/Equipment Repair and Maintenance
 Fuel Dispensing Areas
 Loading Docks
 Fire Sprinkler Test Water
 Miscellaneous Drain or Wash Water
 Plazas, sidewalks, and parking lots

Description / Additional Information:

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 7 of 10, Form Date: March 15, 2016
Identification and Narrative of Receiving Water and Pollutants of Concern Describe flow path of storm water from the project site discharge location(s), through urban storm conveyance systems as applicable, to receiving creeks, rivers, and lagoons as applicable, and ultimate discharge to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable):

Storm water is collected within a private storm drain system, which conveys flows to an existing private storm drain system on the north side of the site. The existing private storm drain system conveys flows to existing box culvert. The box culvert flows under East Carmel Street and State Route 78 and continues through an existing reinforced concrete pipe which ultimately discharge to San Marcos Creek. San Marcos Creek flows southwest, to Lake San Marcos, and then continues to Batiquitos Lagoon, ultimately discharging to the Pacific Ocean.

List any 303(d) impaired water bodies within the path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing impairment, and identify any TMDLs and/or Highest Priority Pollutants from the WQIP for the impaired water bodies:
303(d) Impaired Water Body Pollutant(s)/Stressor(s)
TMDLs / WQIP Highest Priority
Pollutant
San Marcos Creek DDE, Phosphorous, Selenium,
Sediment Toxicity
Est. TMDL: 2019 and 2021
San Marcos Lake Ammonia as Nitrogen, Nutrients Est. TMDL: 2019 Identification of Project Site Pollutants*
*Identification of project site pollutants is only required if flow-thru treatment BMPs are implemented onsite in lieu of retention or biofiltration BMPs (note the project must also participate in an alternative compliance program unless prior lawful approval to meet earlier PDP requirements is demonstrated)
Identify pollutants expected from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6):

Pollutant
Not Applicable to the
Project Site
Expected from the
Project Site
Also a Receiving Water
Pollutant of Concern
Sediment X
Nutrients X X
Heavy Metals X X
Organic Compounds X
Trash & Debris X
Oxygen Demanding
Substances X
Oil & Grease X
Bacteria & Viruses X
Pesticides X X
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025

Form I-3B Page 8 of 10, Form Date: March 15, 2016
Hydromodification Management Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)?  Yes, hydromodification management flow control structural BMPs required.  No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean.  No, the project will discharge runoff directly to conveyance channels whose bed and bank are concrete-lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean.
 No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides.

Description / Additional Information (to be provided if a 'No' answer has been selected above):

Critical Coarse Sediment Yield Areas*
*This Section only required if hydromodification management requirements apply Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries?
 Yes
 No, No critical coarse sediment yield areas to be protected based on WMAA maps

If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed?
 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite  6.2.2 Downstream Systems Sensitivity to Coarse Sediment  6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite  No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps

If optional analyses were performed, what is the final result?  No critical coarse sediment yield areas to be protected based on verification of GLUs onsite  Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 2.b of the SWQMP.  Critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit.

Discussion / Additional Information:

See attachment 2b.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 9 of 10, Form Date: March 15, 2016
Flow Control for Post-Project Runoff*
*This Section only required if hydromodification management requirements apply List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see Section 6.3.1). For each POC, provide a POC identification name or number correlating to the project's HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP Exhibit.

The project is tributary to a single POC, an existing outlet at San Marcos Creek, north of Highway 78.

Has a geomorphic assessment been performed for the receiving channel(s)?  No, the low flow threshold is 0.1Q2 (default low flow threshold)  Yes, the result is the low flow threshold is 0.1Q2
 Yes, the result is the low flow threshold is 0.3Q2
 Yes, the result is the low flow threshold is 0.5Q2

If a geomorphic assessment has been performed, provide title, date, and preparer:

Hydromodification Screening for NC – Enterprise Affordable Housing dated September 14, 2024 prepared by Chang Consultants.

Discussion / Additional Information: (optional)

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-3B Page 10 of 10, Form Date: March 15, 2016
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water management design, such as zoning requirements including setbacks and open space, or local codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements.

The proposed project has existing high tail water condition at discharge points within existing storm drain systems. In final engineering, the use of backwater valves and other design methods will be implemented to prevent impacts in proposed systems.

Optional Additional Information or Continuation of Previous Sections As Needed This space provided for additional information or continuation of information from previous sections as needed.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Source Control BMP Checklist
for All Development Projects
(Standard Projects and Priority Development Projects)
Form I-4
[March 15, 2016]
Project Identification
Project Name: CUBESMART SELF STORAGE
Permit Application Number: CUP24-0005
Source Control BMPs
All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible. See Chapter 4 and Appendix E of the Model BMP Design Manual for information to implement source control BMPs shown in this checklist.

Answer each category below pursuant to the following.
 "Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E of the Model BMP Design Manual. Discussion / justification is not required.  "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion / justification must be provided.
 "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas).

Discussion / justification may be provided.

Source Control Requirement Applied?
SC-1 Prevention of Illicit Discharges into the MS4  Yes  No  N/A Discussion / justification if SC-1 not implemented:

SC-2 Storm Drain Stenciling or Signage  Yes  No  N/A Discussion / justification if SC-2 not implemented:

SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal
 Yes  No  N/A
Discussion / justification if SC-3 not implemented:

SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and Wind Dispersal
 Yes  No  N/A
Discussion / justification if SC-4 not implemented:

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-4 Page 2 of 2, Form Date: March 15, 2016
Source Control Requirement Applied?
SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal
 Yes  No  N/A
Discussion / justification if SC-5 not implemented:

SC-6 Additional BMPs Based on Potential Sources of Runoff Pollutants (must answer for each source listed below)
 On-site storm drain inlets
 Interior floor drains and elevator shaft sump pumps
 Interior parking garages
 Need for future indoor & structural pest control
 Landscape/Outdoor Pesticide Use
 Pools, spas, ponds, decorative fountains, and other water features  Food service
 Refuse areas
 Industrial processes
 Outdoor storage of equipment or materials
 Vehicle and Equipment Cleaning
 Vehicle/Equipment Repair and Maintenance
 Fuel Dispensing Areas
 Loading Docks
 Fire Sprinkler Test Water
 Miscellaneous Drain or Wash Water
 Plazas, sidewalks, and parking lots

 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes
 Yes

 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No
 No

 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
 N/A
Discussion / justification if SC-6 not implemented. Clearly identify which sources of runoff pollutants are discussed. Justification must be provided for all "No" answers shown above.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Site Design BMP Checklist
for All Development Projects
(Standard Projects and Priority Development Projects)
Form I-5
[March 15, 2016]
Project Identification
Project Name: CUBESMART SELF STORAGE
Permit Application Number: CUP24-0005
Site Design BMPs
All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See Chapter 4 and Appendix E of the Model BMP Design Manual for information to implement site design BMPs shown in this checklist.

Answer each category below pursuant to the following.
 "Yes" means the project will implement the site design BMP as described in Chapter 4 and/or Appendix E of the Model BMP Design Manual. Discussion / justification is not required.  "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion / justification must be provided.
 "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project site has no existing natural areas to conserve).

Discussion / justification may be provided.

Site Design Requirement Applied?
SD-1 Maintain Natural Drainage Pathways and Hydrologic Features  Yes  No  N/A Discussion / justification if SD-1 not implemented:

The project site has been previously rough graded per GP21-00004.

SD-2 Conserve Natural Areas, Soils, and Vegetation  Yes  No  N/A Discussion / justification if SD-2 not implemented:

The project site has been previously rough graded per GP21-00004.

SD-3 Minimize Impervious Area  Yes  No  N/A
Discussion / justification if SD-3 not implemented:

SD-4 Minimize Soil Compaction  Yes  No  N/A
Discussion / justification if SD-4 not implemented:

SD-5 Impervious Area Dispersion  Yes  No  N/A
Discussion / justification if SD-5 not implemented:

Although proposed impervious surfaces will drain to pervious areas, the flow length is not typically 10’ min. Biofiltration is the primary treatment method proposed.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-5 Page 2 of 2, Form Date: March 15, 2016
Site Design Requirement Applied?
SD-6 Runoff Collection  Yes  No  N/A
Discussion / justification if SD-6 not implemented:

SD-7 Landscaping with Native or Drought Tolerant Species  Yes  No  N/A Discussion / justification if SD-7 not implemented:

SD-8 Harvesting and Using Precipitation  Yes  No  N/A Discussion / justification if SD-8 not implemented:

Per the Harvest and Use Feasibility Screening Checklist (Attachment 1c), harvesting and use of precipitation is not feasible.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Summary of PDP Structural BMPs Form I-6 (PDPs)
[March 15, 2016]
Project Identification
Project Name: CUBESMART SELF STORAGE
Permit Application Number: CUP24-0005
PDP Structural BMPs
All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control must be based on the selection process described in Chapter 5. PDPs subject to hydromodification management requirements must also implement structural BMPs for flow control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both storm water pollutant control and flow control for hydromodification management can be achieved within the same structural BMP(s).

PDP structural BMPs must be verified by the local jurisdiction at the completion of construction. This may include requiring the project owner or project owner's representative and engineer of record to certify construction of the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must be maintained into perpetuity, and the local jurisdiction must confirm the maintenance (see Section 7 of the BMP Design Manual).

Use this form to provide narrative description of the general strategy for structural BMP implementation at the project site in the box below. Then complete the PDP structural BMP summary information sheet (page 3 of this form) for each structural BMP within the project (copy the BMP summary information page as many times as needed to provide summary information for each individual structural BMP).

Describe the general strategy for structural BMP implementation at the site. This information must describe how the steps for selecting and designing storm water pollutant control BMPs presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether pollutant control and flow control BMPs are integrated or separate.

After calculating the DCV for each DMA, a feasibility analysis was performed for infiltration potential and “No Infiltration Condition” was selected, which led to the selection of Biofiltration BMPs, per fact sheet B.1-1, for use at the site. The project proposes 2 proprietary biofiltration systems and 2 underground storage systems.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-6 Page 3 of X (Copy as many as needed) Form Date: March 15, 2016 Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural BMP) Structural BMP ID No. PBF-1
Construction Plan Sheet No. C4
Type of structural BMP:
 Retention by harvest and use (HU-1)
 Retention by infiltration basin (INF-1)
 Retention by bioretention (INF-2)
 Retention by permeable pavement (INF-3)
 Partial retention by biofiltration with partial retention (PR-1)  Biofiltration (BF-1)
 Biofiltration with Nutrient Sensitive Media Design (BF-2)  Proprietary Biofiltration (BF-3) meeting all requirements of Appendix F  Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below)
 Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below)
 Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below)
 Detention pond or vault for hydromodification management  Other (describe in discussion section below)

Purpose:
 Pollutant control only
 Hydromodification control only
 Combined pollutant control and hydromodification control  Pre-treatment/forebay for another structural BMP
 Other (describe in discussion section below)

Who will certify construction of this BMP?
Provide name and contact information for the
party responsible to sign BMP verification forms if
required by the [City Engineer] (See Section 1.12 of
the BMP Design Manual)
Joseph G. Cresto
Stevens Cresto Engineers
9665 Chesapeake Drive, Suite 200
San Diego, CA 92123
(858) 694-5660
Who will be the final owner of this BMP?

CubeSmart Self Storage
Who will maintain this BMP into perpetuity?

CubeSmart Self Storage
What is the funding mechanism for maintenance?

Private maintenance will be budgeted with other
site costs.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-6 Page 3 of X (Copy as many as needed) Form Date: March 15, 2016 Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural BMP) Structural BMP ID No. PBF-2
Construction Plan Sheet No. C4
Type of structural BMP:
 Retention by harvest and use (HU-1)
 Retention by infiltration basin (INF-1)
 Retention by bioretention (INF-2)
 Retention by permeable pavement (INF-3)
 Partial retention by biofiltration with partial retention (PR-1)  Biofiltration (BF-1)
 Biofiltration with Nutrient Sensitive Media Design (BF-2)  Proprietary Biofiltration (BF-3) meeting all requirements of Appendix F  Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below)
 Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below)
 Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below)
 Detention pond or vault for hydromodification management  Other (describe in discussion section below)

Purpose:
 Pollutant control only
 Hydromodification control only
 Combined pollutant control and hydromodification control  Pre-treatment/forebay for another structural BMP
 Other (describe in discussion section below)

Who will certify construction of this BMP?
Provide name and contact information for the
party responsible to sign BMP verification forms if
required by the [City Engineer] (See Section 1.12 of
the BMP Design Manual)
Joseph G. Cresto
Stevens Cresto Engineers
9665 Chesapeake Drive, Suite 200
San Diego, CA 92123
(858) 694-5660
Who will be the final owner of this BMP?

CubeSmart Self Storage
Who will maintain this BMP into perpetuity?

CubeSmart Self Storage
What is the funding mechanism for maintenance?

Private maintenance will be budgeted with other
site costs.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-6 Page 3 of X (Copy as many as needed) Form Date: March 15, 2016 Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural BMP) Structural BMP ID No. UD-1
Construction Plan Sheet No. C4
Type of structural BMP:
 Retention by harvest and use (HU-1)
 Retention by infiltration basin (INF-1)
 Retention by bioretention (INF-2)
 Retention by permeable pavement (INF-3)
 Partial retention by biofiltration with partial retention (PR-1)  Biofiltration (BF-1)
 Biofiltration with Nutrient Sensitive Media Design (BF-2)  Proprietary Biofiltration (BF-3) meeting all requirements of Appendix F  Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below)
 Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below)
 Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below)
 Detention pond or vault for hydromodification management  Other (describe in discussion section below)

Purpose:
 Pollutant control only
 Hydromodification control only
 Combined pollutant control and hydromodification control  Pre-treatment/forebay for another structural BMP
 Other (describe in discussion section below)
100-yr peak flow detention
Who will certify construction of this BMP?
Provide name and contact information for the
party responsible to sign BMP verification forms if
required by the [City Engineer] (See Section 1.12 of
the BMP Design Manual)
Joseph G. Cresto
Stevens Cresto Engineers
9665 Chesapeake Drive, Suite 200
San Diego, CA 92123
(858) 694-5660
Who will be the final owner of this BMP?

CubeSmart Self Storage
Who will maintain this BMP into perpetuity?

CubeSmart Self Storage
What is the funding mechanism for maintenance?

Private maintenance will be budgeted with other
site costs.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Form I-6 Page 3 of X (Copy as many as needed) Form Date: March 15, 2016 Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural BMP) Structural BMP ID No. UD-2
Construction Plan Sheet No. C4
Type of structural BMP:
 Retention by harvest and use (HU-1)
 Retention by infiltration basin (INF-1)
 Retention by bioretention (INF-2)
 Retention by permeable pavement (INF-3)
 Partial retention by biofiltration with partial retention (PR-1)  Biofiltration (BF-1)
 Biofiltration with Nutrient Sensitive Media Design (BF-2)  Proprietary Biofiltration (BF-3) meeting all requirements of Appendix F  Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below)
 Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below)
 Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below)
 Detention pond or vault for hydromodification management  Other (describe in discussion section below)

Purpose:
 Pollutant control only
 Hydromodification control only
 Combined pollutant control and hydromodification control  Pre-treatment/forebay for another structural BMP
 Other (describe in discussion section below)
100-yr peak flow detention
Who will certify construction of this BMP?
Provide name and contact information for the
party responsible to sign BMP verification forms if
required by the [City Engineer] (See Section 1.12 of
the BMP Design Manual)
Joseph G. Cresto
Stevens Cresto Engineers
9665 Chesapeake Drive, Suite 200
San Diego, CA 92123
(858) 694-5660
Who will be the final owner of this BMP?

CubeSmart Self Storage
Who will maintain this BMP into perpetuity?

CubeSmart Self Storage
What is the funding mechanism for maintenance?

Private maintenance will be budgeted with other
site costs.

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
ATTACHMENT 1

BACKUP FOR PDP POLLUTANT CONTROL BMPS

This is the cover sheet for Attachment 1.

Indicate which Items are Included behind this cover sheet:

Attachment
Sequence
Contents Checklist
Attachment 1a DMA Exhibit (Required)

See DMA Exhibit Checklist on the back of
this Attachment cover sheet.

 Included

Attachment 1b Tabular Summary of DMAs Showing DMA
ID matching DMA Exhibit, DMA Area, and
DMA Type (Required)*

*Provide table in this Attachment OR on
DMA Exhibit in Attachment 1a

 Included on DMA Exhibit in
Attachment 1a
 Included as Attachment 1b, separate
from DMA Exhibit

Attachment 1c Form I-7, Harvest and Use Feasibility
Screening Checklist (Required unless the
entire project will use infiltration BMPs)

Refer to Appendix B.3-1 of the BMP
Design Manual to complete Form I-7.

 Included
 Not included because the entire
project will use infiltration BMPs

Attachment 1d Form I-8, Categorization of Infiltration
Feasibility Condition (Required unless the
project will use harvest and use BMPs)

Refer to Appendices C and D of the BMP
Design Manual to complete Form I-8.

 Included
 Not included because the entire
project will use harvest and use BMPs

Attachment 1e Pollutant Control BMP Design
Worksheets / Calculations (Required)

Refer to Appendices B and E of the BMP
Design Manual for structural pollutant
control BMP design guidelines

 Included

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Use this checklist to ensure the required information has been included on the DMA Exhibit:

The DMA Exhibit must identify:

 Underlying hydrologic soil group
 Approximate depth to groundwater
 Existing natural hydrologic features (watercourses, seeps, springs, wetlands)  Critical coarse sediment yield areas to be protected
 Existing topography and impervious areas
 Existing and proposed site drainage network and connections to drainage offsite  Proposed demolition
 Proposed grading
 Proposed impervious features
 Proposed design features and surface treatments used to minimize imperviousness  Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square footage or acreage), and DMA type (i.e., drains to BMP, self-retaining, or self-mitigating)  Potential pollutant source areas and corresponding required source controls (see Chapter 4, Appendix E.1, and Form I-3B)
 Structural BMPs (identify location, type of BMP, and size/detail)

Attachment 1a

DMA Exhibit

Attachment 1c

Worksheet B.3-1 (Form I-7), Harvest and Use Feasibility Screening Checklist

/0 /1 /1 /2 /3 /4 /5 /6 □ /8 /9 □ /10 /11 /12 /13 /14 □ /15 /3 /4 □ /16 /17 /2 /18 /19 /20 /5 /14 /21 /14□ □
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/70 /51 /35 □ /36 /37 □ /38 /39 /40 □ /70 /71 □ /39 /47 /60 /41 □ /43 /40 /44 /42 /45 /43 □ /53 /40 /37 /37 □ /38 /39 /42 /45 □ /88 /35 /68 /89 /80 /79 /81 /62 □ □ □ □ □ □ □ /85 □ □ □ □ □ /86 /40 /37 □
/90 /42 /41 /48 /40 /37 /38 □ /42 /45 /43 □ /60 /37 /40 □ /42 /54 /54 /40 /42 /41 /37 □ /38 /47 □ /59 /40 □ /46 /40 /42 /37 /58 /59 /53 /40 /35 □ /79 /47 /45 /43 /60 /51 /38 □ /44 /47 /41 /40 □ /43 /40 /38 /42 /58 /53 /40 /43 □ /40 /48 /42 /53 /60 /42 /38 /58 /47 /45 □ /42 /45 /43 □ /37 /58 /91 /58 /45 /61 □ /51 /42 /53 /51 /60 /53 /42 /38 /58 /47 /45 /37 □ /38 /47 □ /51 /47 /45 /46 /58 /41 /44 □ /38 /39 /42 /38 □ /80 /79 /81 □ /51 /42 /45 □ /59 /40 □ /60 /37 /40 /43 □ /42 /38 □ /42 /45 □ /42 /43 /40 /84 /60 /42 /38 /40 □ /41 /42 /38 /40 □ /38 /47 □ /44 /40 /40 /38 □ /43 /41 /42 /49 /43 /47 /49 /45 □ /51 /41 /58 /38 /40 /41 /58 /42 /35 □ /90 /42 /41 /48 /40 /37 /38 □ /42 /45 /43 □ /60 /37 /40 □ /44 /42 /55 □ /59 /40 □ /46 /40 /42 /37 /58 /59 /53 /40 /35 □ /79 /47 /45 /43 /60 /51 /38 □ /44 /47 /41 /40 □ /43 /40 /38 /42 /58 /53 /40 /43 □ /40 /48 /42 /53 /60 /42 /38 /58 /47 /45 □ /42 /45 /43 □ /37 /58 /91 /58 /45 /61 □ /51 /42 /53 /51 /60 /53 /42 /38 /58 /47 /45 /37 □ /38 /47 □ /43 /40 /38 /40 /41 /44 /58 /45 /40 □ /46 /40 /42 /37 /58 /59 /58 /53 /58 /38 /55 /35 □ /90 /42 /41 /48 /40 /37 /38 □ /42 /45 /43 □ /60 /37 /40 □ /44 /42 /55 □ /47 /45 /53 /55 □ /59 /40 □ /42 /59 /53 /40 □ /38 /47 □ /59 /40 □ /60 /37 /40 /43 □ /46 /47 /41 □ /42 □ /54 /47 /41 /38 /58 /47 /45 □ /47 /46 □ /38 /39 /40 □ /37 /58 /38 /40 /92 □ /47 /41 □ /50 /47 /54 /38 /58 /47 /45 /42 /53 /53 /55 /56 □ /38 /39 /40 □ /37 /38 /47 /41 /42 /61 /40 □ /44 /42 /55 □ /45 /40 /40 /43 □ /38 /47 □ /59 /40 □ /60 /54 /37 /58 /91 /40 /43 □ /38 /47 □ /44 /40 /40 /38 □ /53 /47 /45 /61 □ /38 /40 /41 /44 □ /51 /42 /54 /38 /60 /41 /40 □ /38 /42 /41 /61 /40 /38 /37 □ /49 /39 /58 /53 /40 □ /43 /41 /42 /58 /45 /58 /45 /61 □ /58 /45 □ /53 /47 /45 /61 /40 /41 □ /38 /39 /42 /45 □ /70 /71 □ /39 /47 /60 /41 /37 /35 □ /90 /42 /41 /48 /40 /37 /38 □ /42 /45 /43 □ /60 /37 /40 □ /58 /37 □ /51 /47 /45 /37 /58 /43 /40 /41 /40 /43 □ /38 /47 □ /59 /40 □ /58 /45 /46 /40 /42 /37 /58 /59 /53 /40 /35 □
/36 /37 □ /39 /42 /41 /48 /40 /37 /38 □ /42 /45 /43 □ /60 /37 /40 □ /46 /40 /42 /37 /58 /59 /53 /40 □ /59 /42 /37 /40 /43 □ /47 /45 □ /46 /60 /41 /38 /39 /40 /41 □ /40 /48 /42 /53 /60 /42/38 /58 /47 /45 /62 □ □ /85 □ /86 /40 /37 /92 □ /41 /40 /46 /40 /41 □ /38 /47 □ /93 /54 /54 /40 /45 /43 /58 /94 □ /95 □ /38 /47 □ /37 /40 /53 /40 /51 /38 □ /42 /45 /43 □ /37 /58 /91 /40 □ /39 /42 /41 /48 /40/37 /38 □ /42 /45 /43 □ /60 /37 /40 □ /75 /96 /77 /37 /35 □ □ /85 □ /87 /47 /92 □ /37 /40 /53 /40 /51 /38 □ /42 /53 /38 /40 /41 /45 /42 /38 /40 □ /75 /96 /77 /37 /35□ □
36-Hour Irrigation demand: 390 gal/AC (Table B.3-3 For Low Water Use).

For total landscape area: 0.333 ac. Irrigation demand: 130 gal, or 17.4 CF. 4,679

Attachment 1d

Worksheet C.4-1 (Form I-8), Categorization of Infiltration Feasibility

(TO BE PROVIDED AT FINAL ENGINEERING)
Attachment 1e

Pollutant Control BMP Design Worksheets/Calculations

Category # Description i ii iii iv v vi vii viii ix x Units 1 Drainage Basin ID or Name PBF-1 PBF-2 unitless
2 85th Percentile 24-hr Storm Depth 0.68 0.68 inches
3 Impervious Surfaces Not Directed to Dispersion Area (C=0.90) 50,685 39,745 sq-ft 4 Semi-Pervious Surfaces Not Serving as Dispersion Area (C=0.30) sq-ft 5 Engineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10) 6,075 8,410 sq-ft 6 Natural Type A Soil Not Serving as Dispersion Area (C=0.10) sq-ft 7 Natural Type B Soil Not Serving as Dispersion Area (C=0.14) sq-ft 8 Natural Type C Soil Not Serving as Dispersion Area (C=0.23) sq-ft 9 Natural Type D Soil Not Serving as Dispersion Area (C=0.30) sq-ft 10 Does Tributary Incorporate Dispersion, Tree Wells, and/or Rain Barrels? No No yes/no 11 Impervious Surfaces Directed to Dispersion Area per SD-B (Ci=0.90) sq-ft 12 Semi-Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft 13 Engineered Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft 14 Natural Type A Soil Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft 15 Natural Type B Soil Serving as Dispersion Area per SD-B (Ci=0.14) sq-ft 16 Natural Type C Soil Serving as Dispersion Area per SD-B (Ci=0.23) sq-ft 17 Natural Type D Soil Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft 18 Number of Tree Wells Proposed per SD-A #
19 Average Mature Tree Canopy Diameter ft
20 Number of Rain Barrels Proposed per SD-E #
21 Average Rain Barrel Size gal
22 Total Tributary Area 56,760 48,155 0 0 0 0 0 0 0 0 sq-ft 23 Initial Runoff Factor for Standard Drainage Areas 0.81 0.76 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 24 Initial Runoff Factor for Dispersed & Dispersion Areas 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 25 Initial Weighted Runoff Factor 0.81 0.76 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 26 Initial Design Capture Volume 2,605 2,074 0 0 0 0 0 0 0 0 cubic-feet 27 Total Impervious Area Dispersed to Pervious Surface 0 0 0 0 0 0 0 0 0 0 sq-ft 28 Total Pervious Dispersion Area 0 0 0 0 0 0 0 0 0 0 sq-ft 29 Ratio of Dispersed Impervious Area to Pervious Dispersion Area n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a ratio 30 Adjustment Factor for Dispersed & Dispersion Areas 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 ratio 31 Runoff Factor After Dispersion Techniques 0.81 0.76 n/a n/a n/a n/a n/a n/a n/a n/a unitless 32 Design Capture Volume After Dispersion Techniques 2,605 2,074 0 0 0 0 0 0 0 0 cubic-feet 33 Total Tree Well Volume Reduction 0 0 0 0 0 0 0 0 0 0 cubic-feet 34 Total Rain Barrel Volume Reduction 0 0 0 0 0 0 0 0 0 0 cubic-feet 35 Final Adjusted Runoff Factor 0.81 0.76 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 36 Final Effective Tributary Area 45,976 36,598 0 0 0 0 0 0 0 0 sq-ft 37 Initial Design Capture Volume Retained by Site Design Elements 0 0 0 0 0 0 0 0 0 0 cubic-feet 38 Final Design Capture Volume Tributary to BMP 2,605 2,074 0 0 0 0 0 0 0 0 cubic-feet False
False
Automated Worksheet B.1: Calculation of Design Capture Volume (V2.0) Dispersion
Area, Tree Well
& Rain Barrel
Inputs
(Optional)
Standard
Drainage Basin
Inputs
Results
Tree & Barrel
Adjustments
Initial Runoff
Factor
Calculation
Dispersion
Area
Adjustments
No Warning Messages
2,605 CF X 1.5 = 3,907.5 CF
3,907.5 CF < 10,072 CF PER MANUFACTURER
MWS-L-8-8 PROVIDES ADEQUATE WATER
QUALITY TREATMENT.
2,074 CF X 1.5 = 3,111 CF
3,111 CF < 10,072 CF PER MANUFACTURER
MWS-L-8-8 PROVIDES ADEQUATE WATER
QUALITY TREATMENT.

Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods

B-8 February 26, 2016

Figure B.1-1: 85th Percentile 24-hour Isopluvial Map

PROJECT

LOCATION
~ 0.68 IN.

MWS Linear
Advanced Stormwater Biofiltration
Contents
1 Introduction
2 Applications
3 Configurations
4 Advantages
5 Operation
6 Orientations | Bypass
7 Performance | Approvals
8 Sizing
9 Installation | Maintenance | Plants
www.ModularWetlands.com
The Urban Impact
For hundreds of years natural wetlands surrounding our shores have played an integral role as nature’s stormwater treatment system. But as our cities grow and develop, these natural wetlands have perished under countless roads, rooftops, and
parking lots.

Plant A Wetland
Without natural wetlands our cities are deprived of water purification, flood control, and land stability. Modular Wetlands and the MWS Linear re-establish nature’s presence and rejuvenate water ways in urban areas.

MWS Linear
The Modular Wetland System Linear represents a pioneering breakthrough in stormwater technology as the only biofiltration system to utilize patented horizontal flow, allowing for a smaller footprint and higher treatment capacity. While most biofilters use little or no pre- treatment, the MWS Linear incorporates an advanced pre-treatment chamber that includes separation and pre-filter cartridges. In this chamber sediment and hydrocarbons are removed from runoff before it enters the biofiltration chamber, in turn reducing maintenance costs and improving performance.

Parking Lots
Parking lots are designed to maximize space and
the MWS Linear’s 4 ft. standard planter width
allows for easy integration into parking lot islands
and other landscape medians.

Mixed Use
The MWS Linear can be installed as a raised
planter to treat runoff from rooftops or patios,
making it perfect for sustainable “live-work”
spaces.

Industrial
Many states enforce strict regulations for
discharges from industrial sites. The MWS Linear
has helped various sites meet difficult EPA
mandated effluent limits for dissolved metals and
other pollutants.

Residential
Low to high density developments can benefit
from the versatile design of the MWS Linear.

The system can be used in both decentralized
LID design and cost-effective end-of-the-line
configurations.

Streets
Street applications can be challenging due to
limited space. The MWS Linear is very adaptable,
and offers the smallest footprint to work around
the constraints of existing utilities on retrofit
projects.

Commercial
Compared to bioretention systems, the MWS Linear
can treat far more area in less space - meeting
treatment and volume control requirements.

Applications
The MWS Linear has been successfully used on numerous new construction and retrofit projects. The system’s superior versatility makes it beneficial for a wide range of stormwater and waste water applications - treating rooftops, streetscapes, parking lots, and industrial sites.

More applications are available on our website: www.ModularWetlands.com/Applications • Agriculture
• Reuse
• Low Impact Development
• Waste Water
www.ModularWetlands.com | Page 3
Configurations
The MWS Linear is the preferred biofiltration system of Civil Engineers across the country due to its versatile design. This highly versatile system has available “pipe-in” options on most models, along with built-in curb or grated inlets for simple integration into your stormdrain design.

Curb T ype
The Curb Type configuration accepts sheet flow through a curb opening and is commonly used along road ways and parking lots. It can be used in sump or flow by conditions. Length of curb opening varies based on model and size.

Grate T ype
The Grate Type configuration offers the same features and benefits as the Curb Type but with a grated/drop inlet above the systems pre-treatment chamber.

It has the added benefit of allowing for pedestrian access over the inlet. ADA compliant grates are available to assure easy and safe access. The Grate Type can also be used in scenarios where runoff needs to be intercepted on both sides of landscape islands.

Downspout T ype
The Downspout Type is a variation of the Vault Type and is designed to accept a vertical downspout pipe from roof top and podium areas. Some models have the option of utilizing an internal bypass, simplifying the overall design. The system can be installed as a raised planter and the exterior can be stuccoed or covered with other finishes to match the look of adjacent buildings.

Vault T ype
The system’s patented horizontal flow biofilter is able to accept inflow pipes directly into the pre-treatment chamber, meaning the MWS Linear can be used in end-of-the-line installations. This greatly improves feasibility over typical decentralized designs that are required with other biofiltration/bioretention systems. Another benefit of the “pipe in” design is the ability to install the system downstream of underground detention systems to meet water quality volume requirements.

Cartridge Housing
Pre-filter Cartridge
Curb Inlet
Individual Media Filters
Advantages & Operation
The MWS Linear is the most efficient and versatile biofiltration system on the market, and the only system with horizontal flow which improves performance, reduces footprint, and minimizes maintenance. Figure-1 and Figure-2 illustrate the invaluable benefits of horizontal flow and the multiple treatment stages. • Horizontal Flow Biofiltration
• Greater Filter Surface Area
• Pre-Treatment Chamber
• Patented Perimeter Void Area
• Flow Control
• No Depressed Planter Area
Separation
• Trash, sediment, and debris are separated before
entering the pre-filter cartridges
• Designed for easy maintenance access
Pre-Filter Cartridges
• Over 25 ft2 of surface area per cartridge
• Utilizes BioMediaGREEN filter material
• Removes over 80% of TSS & 90% of hydrocarbons
• Prevents pollutants that cause clogging from
migrating to the biofiltration chamber
Pre-Treatment1
1 2
Drain-Down Line
1 2
Vertical Underdrain
Manifold
Featured Advantages
www.ModularWetlands.com | Page 5
Fig. 1
Horizontal Flow
• Less clogging than downward flow biofilters
• Water flow is subsurface
• Improves biological filtration
Patented Perimeter Void Area
• Vertically extends void area between the walls
and the WetlandMEDIA on all four sides.
• Maximizes surface area of the media for higher
treatment capacity
WetlandMEDIA
• Contains no organics and removes phosphorus
• Greater surface area and 48% void space
• Maximum evapotranspiration
• High ion exchange capacity and light weight
Flow Control
• Orifice plate controls flow of water through
WetlandMEDIA to a level lower than the
media’s capacity.
• Extends the life of the media and improves
performance
Drain-Down Filter
• The Drain-Down is an optional feature that
completely drains the pre-treatment
chamber
• Water that drains from the pre-treatment
chamber between storm events will be
treated
2x to 3x More Surface Area Than Traditional Downward Flow Bioretention Systems.Fig. 2 - T op View Biofiltration2
Discharge3
Perimeter Void Area
3 4
3 Flow Control Riser
Drain-Down Line
Outlet Pipe

Orientations
Bypass
Internal Bypass Weir (Side-by-Side Only)
The Side-By-Side orientation places the pre-
treatment and discharge chambers adjacent to
one another allowing for integration of internal
bypass. The wall between these chambers can act
as a bypass weir when flows exceed the system’s
treatment capacity, thus allowing bypass from the
pre-treatment chamber directly to the discharge
chamber.

External Diversion Weir Structure
This traditional offline diversion method can be
used with the MWS Linear in scenarios where runoff
is being piped to the system. These simple and
effective structures are generally configured with
two outflow pipes. The first is a smaller pipe on the
upstream side of the diversion weir - to divert low
flows over to the MWS Linear for treatment. The
second is the main pipe that receives water once the
system has exceeded treatment capacity and water
flows over the weir.

Flow By Design
This method is one in which the system is placed
just upstream of a standard curb or grate inlet to
intercept the first flush. Higher flows simply pass
by the MWS Linear and into the standard inlet
downstream.

End-T o-End
The End-To-End orientation places the pre-treatment
and discharge chambers on opposite ends of the
biofiltration chamber therefore minimizing the
width of the system to 5 ft (outside dimension). This
orientation is perfect for linear projects and street
retrofits where existing utilities and sidewalks limit
the amount of space available for installation. One
limitation of this orientation is bypass must be
external.

Side-By-Side
The Side-By-Side orientation places the pre-
treatment and discharge chamber adjacent to one
another with the biofiltration chamber running
parallel on either side. This minimizes the system
length, providing a highly compact footprint. It has
been proven useful in situations such as streets with
directly adjacent sidewalks, as half of the system can
be placed under that sidewalk. This orientation also
offers internal bypass options as discussed below.

This simple yet innovative diversion trough can be
installed in existing or new curb and grate inlets to
divert the first flush to the MWS Linear via pipe. It
works similar to a rain gutter and is installed just
below the opening into the inlet. It captures the
low flows and channels them over to a connecting
pipe exiting out the wall of the inlet and leading
to the MWS Linear. The DVERT is perfect for retrofit
and green street applications that allows the MWS
Linear to be installed anywhere space is available.

DVERT Low Flow Diversion
DVERT Trough
www.ModularWetlands.com | Page 7
Rhode Island DEM Approved
Approved as an authorized BMP and noted to achieve the following minimum removal efficiencies: 85% TSS, 60% Pathogens, 30% T otal Phosphorus, and 30% T otal Nitrogen.

MASTEP Evaluation
The University of Massachusetts at Amherst – Water Resources Research Center, issued a technical evaluation report noting removal rates up to 84% TSS, 70% T otal Phosphorus,

68.5% T otal Zinc, and more.

Maryland Department Of The Environment Approved
Granted ESD (Environmental Site Design) status for new construction, redevelopment and retrofitting when designed in accordance with the Design Manual.

Washington State TAPE Approved
The MWS Linear is approved for General Use Level Designation (GULD) for Basic, Enhanced, and Phosphorus treatment at 1 gpm/ft
2 loading rate. The highest performing
BMP on the market for all main pollutant categories.

Approvals
The MWS Linear has successfully met years of challenging technical reviews and testing from some of the most prestigious and demanding agencies in the nation, and perhaps the world.

DEQ Assignment
The Virginia Department of Environmental Quality assigned the MWS Linear, the highest phosphorus removal rating for manufactured treatment devices to meet the new Virginia Stormwater Management Program (VSMP) T echnical Criteria.

VA
TSS T otal
Phosphorus
Ortho
Phosphorus Nitrogen Dissolved Zinc Dissolved
Copper T otal Zinc T otal
Copper Motor Oil
85% 64% 67% 45% 66% 38% 69% 50% 95%
Performance
The MWS Linear continues to outperform other treatment methods with superior pollutant removal for TSS, heavy metals, nutrients, hydrocarbons and bacteria. Since 2007 the MWS Linear has been field tested on numerous sites across the country. With it’s advanced pre-treatment chamber and innovative horizontal flow biofilter, the system is able to effectively remove pollutants through a combination of physical, chemical, and biological filtration processes. With the same biological processes found in natural wetlands, the MWS Linear harnesses natures ability to process, transform, and remove even the most harmful pollutants.

Treatment Flow Sizing Table
Model # Dimensions WetlandMedia
Surface Area
Treatment Flow
Rate (cfs)
MWS-L-4-4 4’ x 4’ 23 ft2 0.052
MWS-L-4-6 4’ x 6’ 32 ft2 0.073
MWS-L-4-8 4’ x 8’ 50 ft2 0.115
MWS-L-4-13 4’ x 13’ 63 ft2 0.144
MWS-L-4-15 4’ x 15’ 76 ft2 0.175
MWS-L-4-17 4’ x 17’ 90 ft2 0.206
MWS-L-4-19 4’ x 19’ 103 ft2 0.237
MWS-L-4-21 4’ x 21’ 117 ft2 0.268
MWS-L-8-8 8’ x 8’ 100 ft2 0.230
MWS-L-8-12 8’ x 12’ 151 ft2 0.346
MWS-L-8-16 8’ x 16’ 201 ft2 0.462
Flow Based Sizing
The MWS Linear can be used in stand alone applications
to meet treatment flow requirements. Since the MWS
Linear is the only biofiltration system that can accept inflow pipes several feet below the surface it can be
used not only in decentralized design applications but
also as a large central end-of-the-line application for maximum feasibility.

Volume Based Sizing
Many states require treatment of a water quality volume and do not offer the option of flow based design. The MWS Linear and its unique horizontal flow makes it the only biofilter that can be used in volume based design installed downstream of ponds, detention basins, and underground storage systems.

Treatment Volume Sizing Table
Model # Treatment Capacity (cu. ft.)
@ 24-Hour Drain Down
Treatment Capacity (cu. ft.)
@ 48-Hour Drain Down
MWS-L-4-4 1140 2280
MWS-L-4-6 1600 3200
MWS-L-4-8 2518 5036
MWS-L-4-13 3131 6261
MWS-L-4-15 3811 7623
MWS-L-4-17 4492 8984
MWS-L-4-19 5172 10345
MWS-L-4-21 5853 11706
MWS-L-8-8 5036 10072
MWS-L-8-12 7554 15109
MWS-L-8-16 10073 20145
PBF-1 & PBF-2

www.ModularWetlands.com | Page 9
Installation
The MWS Linear is simple, easy to install, and has a space efficient design that offers lower excavation and installation costs compared to traditional tree-box type systems. The structure of the system resembles pre- cast catch basin or utility vaults and is installed in a similar fashion.

The system is delivered fully assembled for quick
installation. Generally, the structure can be unloaded and set in place in 15 minutes. Our experienced
team of field technicians are available to supervise
installations and provide technical support.

Plant Selection
Abundant plants, trees, and grasses bring value and an aesthetic benefit to any urban setting, but those in the MWS Linear do even more - they increase pollutant removal. What’s not seen, but very important, is that below grade the stormwater runoff/flow is being subjected to nature’s secret weapon: a dynamic physical, chemical, and biological process working to break down and remove non-point source pollutants. The flow rate is controlled in the MWS Linear, giving the plants more “contact time” so that pollutants are more successfully decomposed, volatilized and incorporated into the biomass of The MWS Linear’s micro/macro flora and fauna.

A wide range of plants are suitable for use in the MWS Linear, but selections vary by location and climate. View suitable plants by selecting the list relative to your project location’s hardy zone.

Please visit www.ModularWetlands.com/Plants for more information and various plant lists.

Maintenance
Reduce your maintenance costs, man hours, and materials with the MWS Linear. Unlike other biofiltration systems that provide no pre-treatment, the MWS Linear is a self-contained treatment train which incorporates simple and effective pre-treatment.

Maintenance requirements for the biofilter itself are almost completely eliminated, as the pre-treatment chamber removes and isolates trash, sediments, and hydrocarbons. What’s left is the simple maintenance of an easily accessible pre-treatment chamber that can be cleaned by hand or with a standard vac truck. Only periodic replacement of low-cost media in the pre-filter cartridges is required for long term operation and there is absolutely no need to replace expensive biofiltration media.

*PROVIDED AS REFERENCE FOR MWS INFILTRATION RATE
*PROVIDED AS REFERENCE FOR MWS INFILTRATION RATE
UD-1 VOLUME SIZING CALC
MODULE SIZE (INTERNAL DIM): 8 ' H X 7 ' W X 15 ' L
NUMBER OF MODULES: 10
HEIGHT = 8 '
H treat
= 3.73 '
V = 8,400 CF
VOLUME PER 1 FT:
8,400 CF = 8 FT
V1FT = 1 FT
V1FT = 1,050 CF
TREATMENT VOLUME: DCV * 1.5 = 2,605 CF * 1.5 = 3907.5 CF HEIGHT OF TREATMENT VOLUME:
1,050 CF = 1 FT
3,907.5 CF = H treat
H treat = 3.73'
1 1
13003.85
KGS
01/20/2025
TOTAL VOLUME (v) = 10 (8 ' x 7 ' x 15 ') = 8,400 CF

Cubesmart Self Storage
hrs
C: 0.6
Surface Depth (ft) Area (sq. ft) Volume (cf)
Qorifice=CoAo*[(2gHo)^0.5]
Vault Drawdown Calculation - UD1
Project Name
Project Number 13003.85 Total Vault Volume (cf)
Vault Drawdown 49.37 Total Chamber Height (ft)
Note: Drawdown time is calculated assuming initial water surface depth equal to the invert of the lowest surface discharge opening in the basin outlet structure. 8400
8 Orifice Diameter: 1.13

2.30 Qorifice (cfs)

3.5 3.73 1050
1050

0.00 1.08

0.00 1.08
3916.5
3675

0.06 0.06
T (hrs) Total Time (hrs)

3.25 1050 3413 0.06 1.22

17.411 1050 1050 0.03 4.39

0.02 3.10
1050 788 0.03 2.53
2100
1575

0.5 1050 525

6.34 9.44

13.02 49.370.0 1050 0 0.00 21.94

23.05 0.75
2 1050
1050
10501.5

0.25 1.27 3.563150 0.06

2.772625

19.94 3 1050

2.5 0.05

0.05 0.04

3.10 3.58

27.434.390.022631050
UD-2 VOLUME SIZING CALC
MODULE SIZE (INTERNAL DIM): 5.5 ' H X 13.67 ' W X 127.54 ' L TOTAL VOLUME: 9,591 CF
HEIGHT = 5.5 '
H treat
= 1.79 '
V = 9,591 CF
VOLUME PER 1 FT:
9,591 CF = 5.5 FT
V1FT = 1 FT
V1FT = 1,743.8 CF
TREATMENT VOLUME: DCV * 1.5 = 2,074 CF * 1.5 = 3,111 CF HEIGHT OF TREATMENT VOLUME:
1,743.8 CF = 1 FT
3,111 CF = H treat
H treat = 1.79'
1 1
13003.85
KGS
01/20/2025

Cubesmart Self Storage
hrs

2.41 2.78

20.58 22.99

25.78 0.75 1743.8

0.5 0.02

0.02697.50.4
1743.8
1743.8

4.40 15.191307.9 0.03

5.39871.9

49.250.0 1743.8 0.0 0.00 15.24

4.82 29.180.2 1743.8 348.8 0.01 3.41

34.000.1
523.1
1743.8 174.4 0.01

0.021743.80.3

10.79 Qorifice (cfs)

1.25 1.79

1.75 1.5
1743.8
1743.8
1743.8
1 1743.8 1743.8 0.03 3.81
Total Time (hrs)
Qorifice=CoAo*[(2gHo)^0.5]
Vault Drawdown Calculation - UD2
Project Name
Project Number 13003.85 Total Vault Volume (cf)
Vault Drawdown 49.25 Total Chamber Height (ft)
Note: Drawdown time is calculated assuming initial water surface depth equal to the invert of the lowest surface discharge opening in the basin outlet structure. 9591

5.5 Orifice Diameter: 1.10

0.04 0.04

0.04 0.04
T (hrs)
1743.8
3121.4
3051.7
2179.8
2615.7

0.00 0.46

3.57 6.98

0.00 0.46

3.11 3.41
C: 0.6
Surface Depth (ft) Area (sq. ft) Volume (cf)
Project:

Chamber Model - MC-3500
Units - Imperial
Number of Chambers - 51
Number of End Caps - 6
Voids in the stone (porosity) - 40 %
Base of Stone Elevation - 0.00 ft
Amount of Stone Above Chambers - 12 in
Amount of Stone Below Chambers - 9 in
Amount of Stone Between Chambers - 6 in
Area of system - 2806 sf Min. Area -
Height of
System
Incremental Single
Chamber
Incremental
Single End Cap
Incremental
Chambers
Incremental
End Cap
Incremental
Stone
Incremental Ch,
EC and Stone
Cumulative
System Elevation
(inches) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (cubic feet) (feet) 66 0.00 0.00 0.00 0.00 93.53 93.53 9590.96 5.50
65 0.00 0.00 0.00 0.00 93.53 93.53 9497.44 5.42
64 0.00 0.00 0.00 0.00 93.53 93.53 9403.91 5.33
63 0.00 0.00 0.00 0.00 93.53 93.53 9310.38 5.25
62 0.00 0.00 0.00 0.00 93.53 93.53 9216.86 5.17
61 0.00 0.00 0.00 0.00 93.53 93.53 9123.33 5.08
60 0.00 0.00 0.00 0.00 93.53 93.53 9029.81 5.00
59 0.00 0.00 0.00 0.00 93.53 93.53 8936.28 4.92
58 0.00 0.00 0.00 0.00 93.53 93.53 8842.75 4.83
57 0.00 0.00 0.00 0.00 93.53 93.53 8749.23 4.75
56 0.00 0.00 0.00 0.00 93.53 93.53 8655.70 4.67
55 0.00 0.00 0.00 0.00 93.53 93.53 8562.17 4.58
54 0.06 0.00 2.96 0.00 92.34 95.30 8468.65 4.50
53 0.19 0.02 9.90 0.14 89.51 99.55 8373.34 4.42
52 0.29 0.04 14.99 0.23 87.44 102.66 8273.79 4.33
51 0.40 0.05 20.59 0.31 85.17 106.06 8171.13 4.25
50 0.69 0.07 35.05 0.41 79.35 114.80 8065.07 4.17
49 1.03 0.09 52.44 0.53 72.34 125.31 7950.27 4.08
48 1.25 0.11 63.73 0.64 67.78 132.15 7824.96 4.00
47 1.42 0.13 72.53 0.76 64.21 137.50 7692.82 3.92
46 1.57 0.14 80.23 0.87 61.09 142.18 7555.32 3.83
45 1.71 0.16 87.06 0.98 58.31 146.35 7413.13 3.75
44 1.83 0.18 93.25 1.09 55.79 150.13 7266.78 3.67
43 1.94 0.20 98.83 1.20 53.51 153.54 7116.65 3.58
42 2.04 0.22 104.08 1.31 51.37 156.76 6963.10 3.50
41 2.13 0.23 108.87 1.41 49.41 159.69 6806.34 3.42
40 2.22 0.25 113.44 1.50 47.55 162.49 6646.65 3.33
39 2.31 0.27 117.65 1.59 45.83 165.07 6484.16 3.25
38 2.38 0.28 121.62 1.68 44.21 167.51 6319.09 3.17
37 2.46 0.29 125.41 1.76 42.66 169.83 6151.58 3.08
36 2.53 0.31 128.94 1.85 41.21 172.00 5981.75 3.00
35 2.59 0.32 132.28 1.93 39.84 174.05 5809.75 2.92
34 2.66 0.33 135.46 2.01 38.54 176.01 5635.70 2.83
33 2.72 0.35 138.47 2.08 37.31 177.86 5459.69 2.75
32 2.77 0.36 141.34 2.16 36.13 179.62 5281.84 2.67
31 2.82 0.37 144.06 2.23 35.01 181.30 5102.21 2.58
30 2.88 0.38 146.65 2.31 33.94 182.90 4920.91 2.50
29 2.92 0.40 149.13 2.38 32.92 184.43 4738.01 2.42
28 2.97 0.41 151.46 2.45 31.96 185.87 4553.58 2.33
27 3.01 0.42 153.63 2.51 31.07 187.21 4367.71 2.25
26 3.05 0.43 155.72 2.58 30.21 188.50 4180.50 2.17
25 3.09 0.44 157.81 2.64 29.35 189.80 3991.99 2.08
24 3.13 0.45 159.66 2.70 28.58 190.94 3802.20 2.00
23 3.17 0.46 161.45 2.77 27.84 192.05 3611.25 1.92
22 3.20 0.47 163.17 2.82 27.13 193.12 3419.20 1.83
21 3.23 0.48 164.79 2.88 26.46 194.13 3226.07 1.75
20 3.26 0.49 166.33 2.94 25.82 195.09 3031.95 1.67
19 3.29 0.50 167.80 2.99 25.21 196.00 2836.86 1.58
18 3.32 0.51 169.22 3.04 24.62 196.88 2640.86 1.50
17 3.34 0.51 170.55 3.09 24.07 197.71 2443.98 1.42
16 3.37 0.52 171.80 3.13 23.55 198.49 2246.27 1.33
15 3.39 0.53 173.02 3.18 23.05 199.24 2047.78 1.25
14 3.41 0.54 174.14 3.22 22.58 199.94 1848.54 1.17
13 3.44 0.54 175.29 3.26 22.11 200.65 1648.60 1.08
12 3.46 0.55 176.34 3.30 21.67 201.31 1447.94 1.00
11 3.48 0.56 177.41 3.33 21.23 201.97 1246.63 0.92
10 3.51 0.59 178.76 3.57 20.59 202.92 1044.66 0.83
9 0.00 0.00 0.00 0.00 93.53 93.53 841.74 0.75
8 0.00 0.00 0.00 0.00 93.53 93.53 748.21 0.67
7 0.00 0.00 0.00 0.00 93.53 93.53 654.68 0.58
6 0.00 0.00 0.00 0.00 93.53 93.53 561.16 0.50
5 0.00 0.00 0.00 0.00 93.53 93.53 467.63 0.42
4 0.00 0.00 0.00 0.00 93.53 93.53 374.11 0.33
3 0.00 0.00 0.00 0.00 93.53 93.53 280.58 0.25
2 0.00 0.00 0.00 0.00 93.53 93.53 187.05 0.17
1 0.00 0.00 0.00 0.00 93.53 93.53 93.53 0.08
StormTech MC-3500 Cumulative Storage Volumes
CUBESMART SELF STORAGE 13003.85 -
UD2
2626 sf min. area
Include Perimeter Stone in Calculations
Click Here for Metric

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
ATTACHMENT 2

BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES

This is the cover sheet for Attachment 2.

 Mark this box if this attachment is empty because the project is exempt from PDP hydromodification management requirements.

Indicate which Items are Included behind this cover sheet:

Attachment
Sequence
Contents Checklist
Attachment 2a Hydromodification Management Exhibit
(Required)

 Included
 N/A – WILL BE PROVIDED AT FINAL

ENGINEERING
See Hydromodification Management
Exhibit Checklist on the back of this
Attachment cover sheet.

Attachment 2b Management of Critical Coarse Sediment
Yield Areas (WMAA Exhibit is required,
additional analyses are optional)

See Section 6.2 of the BMP Design
Manual.
 Exhibit showing project drainage
boundaries marked on WMAA Critical
Coarse Sediment Yield Area Map
(Required)
Optional analyses for Critical Coarse
Sediment Yield Area Determination
 6.2.1 Verification of Geomorphic
Landscape Units Onsite
 6.2.2 Downstream Systems Sensitivity
to Coarse Sediment
 6.2.3 Optional Additional Analysis of
Potential Critical Coarse Sediment
Yield Areas Onsite

Attachment 2c Geomorphic Assessment of Receiving
Channels (Optional)
See Section 6.3.4 of the BMP Design
Manual.
 Not performed
 Included
 Submitted as separate stand-alone
document

Attachment 2d Flow Control Facility Design, including
Structural BMP Drawdown Calculations
and Overflow Design Summary
(Required)
See Chapter 6 and Appendix G of the
BMP Design Manual
 Included
 Submitted as separate stand-alone
document
 N/A – WILL BE PROVIDED AT FINAL

ENGINEERING
Attachment 2e Vector Control Plan (Required when
structural BMPs will not drain in 96
hours)
 Included
 Not required because BMPs will drain
in less than 96 hours

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Use this checklist to ensure the required information has been included on the Hydromodification Management Exhibit:

N/A – WILL BE PROVIDED AT FINAL ENGINEERING

The Hydromodification Management Exhibit must identify:

 Underlying hydrologic soil group
 Approximate depth to groundwater
 Existing natural hydrologic features (watercourses, seeps, springs, wetlands)  Critical coarse sediment yield areas to be protected
 Existing topography
 Existing and proposed site drainage network and connections to drainage offsite  Proposed grading
 Proposed impervious features
 Proposed design features and surface treatments used to minimize imperviousness  Point(s) of Compliance (POC) for Hydromodification Management  Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions)  Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail)

Attachment 2a

Hydromodification Management Exhibit

N/A WILL BE PROVIDED AT FINAL ENGINEERING
Attachment 2b

Management of Critical Coarse Sediment Yield Areas

Attachment 2c

Geomorphic Assessment of Receiving Channels

(TO BE PROVIDED AT FINAL ENGINEERING)

FOR REVIEW ONLY

HYDROMODIFICATION SCREENING

FOR

NC – ENTERPRISE AFFORDABLE HOUSING

September 14, 2024

Will sign and stamp upon approval

Wayne W. Chang, MS, PE 46548
Chang
Civil Engineering ◦ Hydrology ◦ Hydraulics ◦ Sedimentation

P.O. Box 9496
Rancho Santa Fe, CA 92067
(858) 692-0760

FOR REVIEW ONLY
-TABLE OF CONTENTS -

Introduction ...................................................................................................................................1 Domain of Analysis ......................................................................................................................2 Initial Desktop Analysis ................................................................................................................4 Field Screening .............................................................................................................................5 Conclusion ....................................................................................................................................9 Figures.........................................................................................................................................11

APPENDICES

A. SCCWRP Initial Desktop Analysis

B. SCCWRP Field Screening Data

1 INTRODUCTION

The County of San Diego’s March 2011, Final Hydromodification Management Plan; January 8, 2011, Standard Urban Stormwater Mitigation Plan (SUSMP); and City of San Marcos’ February 2016, BMP Design Manual, outline low flow thresholds for hydromodification analyses. The thresholds are based on a percentage of the pre-project 2-year flow (Q 2), i.e., 0.1Q 2 (low flow threshold and high susceptibility to erosion), 0.3Q 2 (medium flow threshold and medium susceptibility to erosion), or 0.5Q 2 (high flow threshold and low susceptibility to erosion). A flow threshold of 0.1Q 2 represents a natural downstream receiving conveyance system with a high susceptibility to bed and/ or bank erosion. This is the default value used for hydromodification analyses and will result in the most conservati ve (largest) on-site facility sizing. A flow threshold of 0.3Q 2 or 0.5Q2 represents downstream receiving conveyance systems with a medium or low susceptibility to erosion, respectively. In order to qualify for a medium or low erosion susceptibility rating, a project must perform a channel screening analysis based on the March 2010, Hydromodification Screening Tools: Field Manual for Assessing Channel Susceptibility, developed by the Southern Californi a Coastal Water Research Project (SCCWRP). The SCCWRP results are compared with the critical shear stress results from the County of San Diego’s Critical Flow Calculator spreadsheet to es tablish the appropriate erosion susceptibility threshold of low, medium, or high.

Vicinity Map

This report provides a hydromodifi cation screening analysis for the proposed NC - Enterprise Affordable Housing redevelopment project located along the north side of Enterprise Street east of the North County Transit District’s Sprinter li ght rail line in the city of San Marcos (see the Vicinity Map). The project is being designed by Stevens Cresto Engineers. Under existing conditions, the project area has been rough grad ed and contains sediment basins per GP21- 00004. Off-site runoff enters the southeasterly portion of the site from a 6-foot by 3.5-foot box culvert. Off-site runoff is also directed westerly towards the site from an earthen ditch along the

2 south side of East Carmel Street . The sediment basin flows and of f-site runoff enter a 6-foot by 5-foot reinforced concrete box culvert near the nor thwest corner of the site that continues north across State Route 78. The box culvert becomes an 84- inch reinforced concrete pipe (RCP) that outlets into San Marcos Creek along the Sprinter rail line (s ee the Study Area Exhibit in Appendix A). San Marcos Creek is a natural wate rcourse at the outlet. San Marcos Creek flows over 6 miles west to Batiquitos Lagoon.

The project proposes a multi-family afford able residential building and right-of-way improvements. The project runoff will be primarily collected and conveyed by a private drainage system. The project runoff will enter proposed biofiltration BMPs, underground detention, and tree wells. The off-site runoff will be conveyed through the site. The treated project runoff and bypassed off-site runoff will enter the 6-foot by 5-foot box culvert and then 84-inch RCP similar to existing conditions. The runoff will then continue to be directed to San Marcos Creek.

The SCCWRP screening tool requires both office and field work to establish the vertical and lateral susceptib ility of a downstream rece iving channel to erosion. The vertical and lateral assessments are performed independently of each other although the la teral results can be affected by the vertic al rating. A screening an alysis was performed to assess the low flow threshold for the project’s point of compliance, which is at the discharg e point from the 84-inch RCP into San Marcos Creek (see Figure 6 and the Study Area Exhibit).

The initial step in performing the SCCWRP scr eening analysis is to establish the domain of analysis and the study reaches within the domain. This is followed by office and field components of the screening tool along with the associ ated analyses and re sults. The following sections cover these procedures in sequence.

DOMAIN OF ANALYSIS

SCCWRP defines an upstream and downstream domain of analys is, which establish the study limits. The County of San Diego’s HMP specifies the downstream domain of analysis based on the SCCWRP criteria. The HMP indicates that the downstream domain is the first point where one of these is reached:

 at least one reach downstream of the first grade control point  tidal backwater/lentic waterbody
 equal order tributary
 accumulation of 50 percent drainage area for stream systems or 100 percent drainage area for urban conveyance systems (storm drains, hardened channels, etc.)

The upstream limit is defined as:

 proceed upstream for 20 channel top widths or to the first grade control point, whichever comes first. Identify hard points that can check headward migration and evidence of active headcutting.
3 SCCWRP defines the maximum spatia l unit, or reach (a reach is circa 20 channel widths), for assigning a susceptibility rating within the domain of analysis to be 200 meters (656 feet). If the domain of analysis is greater than 200 meters , the study area can be subdivided into smaller reaches of less than 200 meters for analysis. Mo st of the units in the HMP’s SCCWRP analysis are metric. Metric units are used in this repor t only where given so in the HMP. Otherwise, English units are used.

Downstream Domain of Analysis
The downstream domain of analysis for the st udy area has been determined by assessing and comparing the four bullet items above. As disc ussed above, the project ’s storm runoff be conveyed in hardened, non-erodible drainage facilities to San Marcos Creek near the Sprinter rail line. The discharge point into San Marcos Cr eek is the point of compliance (POC) for hydromodification purposes (see the Study Area Exhi bit included in Appendix A). The POC is the point below which a drainage course is natural and susceptib le to erosion. The downstream domain of analysis location is selected below this POC.

Per the first bullet item, the first permanent grad e control below the POC was identified during a site visit. The first grade control occurs wher e San Marcos Creek contains a large concrete transition structure approximate ly 1,200 feet downstream of the POC (see Figure 12 and the Study Area Exhibit). The concrete transition struct ure lines the creek bed and banks and directs the creek flow into quintuple box culverts that continue under North Twin Oaks Valley Road.

The concrete transition structure is a permanent facility that acts as a grade control for the upstream channel bed. i.e., it will prevent erosion of the upstream channel bed.

The second bullet item criteria is based on the lentic waterbody. Th e nearest lentic (standing or still water such as ponds, pools, marshes, lakes, etc. ) waterbody is Lake San Marcos. The Lake San Marcos lentic waterbody is further downstr eam from the POC than the permanent grade control, so the second bullet item will not govern over the first bullet item in establishing the downstream domain of analysis location.

The third bullet item is met when the natura l watercourse below a POC confluences with a stream with an equal order or larger tributary area. San Marcos Creek does not confluence with another stream before the grade control, so th e third bullet item will govern over the first in establishing the downstream domain of analysis location.

The fourth bullet item is met when the natu ral stream below a POC accumulates 50 or 100 percent drainage area for natura l or urban drainage systems, re spectively. San Marcos Creek at the POC is a natural dr ainage system, so 50 percent applie s. The San Marcos Creek watershed area at the POC covers approximately 7 square miles (see the Streamstats discussion in the Initial Desktop Analysis section below). Fifty per cent additional drainage area (approximately 3.5 square miles) will not be accumulated along San Marcos Creek between the POC and permanent grade control. Therefore, the fourth bullet item will not govern over the first bullet item.

4 Based on the above information, the downstream domain of analys is location is established by the permanent grade control criteria (bullet ite m 1) and occurs at th e upstream edge of the concrete transition structure in San Marcos Creek.

Upstream Domain of Analysis
San Marcos Creek extends upstream of the POC, so the upstream domain of analysis location must be determined. The upstream domain of analysis location is es tablished by the closer of 20 channel top widths or the firs t upstream grade control. The top of San Marcos Creek is approximately 250 feet wide at the POC, so 20 channel top wi dths is 5,000 feet . A site visit revealed riprap across the creek bed and banks under the Inland Rail Trai l bridge approximately 1,500 feet upstream of the POC (see Figure 1). This is the first upstream grade control point and establishes the upstream domain of analysis location for the POC.

Study Reaches within Domain of Analysis
From the above informa tion, the downstream doma in of analysis location for the POC is based on the grade control criteria. Of th e four bullet criteria, this is the first point reached below the POCs. The grade control criteria requires the do wnstream domain of analysis location to extend one reach (656 feet) below the first grade cont rol. One reach below the first grade control (located at the upstream edge of the concrete tran sition structure) will be within the Twin Oaks Valley Road box culverts. Since the reach belo w the grade control is non-erodible, the downstream domain of analysis location is set at the grade control.

After the upstream and downstream domain of analysis locations are established for the POC, the study reach is identified (see the Study Area Exhibit). The enti re domain of analysis extends along San Marcos Creek from the ups tream domain of analysis lo cation at the riprap under the Inland Rail Trail bridge to the downstream domain of analysis location at the upstream edge of the concrete transition structure. San Marcos Creek has two geometries along the entire domain of analysis. The upper portion is a relatively narrow trapezoidal channel, while the lower portion is a much wider trapezoidal channel. As a resu lt, the domain of analysis was divided into an upper reach, Reach 1, which is 1,103 feet long and a lower reach, Reach 2, which is 1,637 feet long.

Review of topographic mapping, aerial photographs , and field conditions reveals that the physical (channel geometry and slope), vegetati ve, hydraulic, and soil conditions within each reach are relatively uniform. Subdividing Reach 1 and 2 into subreaches of less than 656 feet will not yield varying conclusions. Although the sc reening tool was applied across the entire length of the domain of analysis, the results will be identical for shorter subreaches within Reach 1 and 2.

INITIAL DESKTOP ANALYSIS

After the domain of analysis is established, SCCWRP requires an “initial desktop analysis” that involves office work. The initial desktop analysis establishes the watershed area, mean annual precipitation, valley slope, and valley width. These terms are defined in Form 1, which is included in Appendix A. SCCWRP recommends th e use of National Elevation Data (NED) to 5 determine the watershed area, valley slope, and valley width. NED is similar to USGS quadrangle mapping. The USGS Streamstats program was used to determine the watershed areas tributary to Reach 1 and 2 (see Appendix A). Streamstats is based on the USGS’ Digital Elevation Model and a digital repr esentation of the stream networ k that is equivalent to NED data. The watershed areas are 6.7390 and 7.0066 square miles, respectively.

The mean annual precipitation was obtained from the rain gages closest to the site. These are the Western Regional Climate Center ’s Escondido and Escondido 2 ga ges (see Appendix A). The average annual rainfall measured at the Escondido gage for th e period of record from 1893 to 1979 is 16.22 inches. The average annual rainfall measured at the Escondido 2 gage for the period of record from 1979 to 2013 is 14.93 inches . The time-weighted av erage rainfall from these two gages is 15.85 inches.

Two-foot contour interval S ANGIS topographic mapping was used for the valley slope and valley width. The SANGIS mapping is more de tailed than NED mappi ng, so will yield more accurate results. The valley slop es of Reach 1 and 2 were determined from the SANGIS topographic mapping. The valley slope is the longitudinal slope of the channel bed along the flow line, so it is determined by dividing the el evation difference within Reach 1 and 2 by their lengths.

Reach Tributary Drainage
Area, sq. mi.

Valley Slope,
m/m
Valley Width,
m
1 6.7390 0.00453 4.6
2 7.0066 0.00611 53.3

Table 1. Summary of Drainage Area, Valley Slope, and Valley Width

The above described values were input to a spreadshee t to calculate the s imulated peak flow, screening index, and valley width index outlined in Form 1. The input data and results are tabulated in Appendix A. This completes the initial desktop analysis.

FIELD SCREENING

After the initial deskto p analysis is done, a field assessme nt must be performed. The field assessment is used to establish a natural channel’s vertical and lateral suscep tibility to erosion.

SCCWRP states that although they are admittedly linked, vertical and lateral susceptibility are assessed separately for several reasons. First, vertical and lateral re sponses are primarily controlled by different types of resistance, wh ich, when assessed separa tely, may improve ease of use and lead to increased repeatability compared to an integrated, cross-dimensional assessment. Second, the mechanisti c differences between vertical and lateral responses point to different modeling tools and potentially differe nt management strategies. Having separate screening ratings may better direct users and managers to the most appropriate tools for subsequent analyses.
6 The field screening tool uses combinations of decision trees and checklists. Decision trees are typically used when a question can be answered fairly definitively and/or quantitatively (e.g., d50 < 16 mm). Checklists are used where answers are relatively qualitative (e.g., the condition of a grade control). Low, medium, high, and very high ra tings are applied separately to the vertical and lateral analyses. When the vertical and late ral analyses return divergent values, the most conservative value shall be selected as the flow threshold for the hydromodification analyses.

Vertical Stability
The purpose of the vertical stability decision tree (Figure 6-4 in the County of San Diego HMP) is to assess the state of the cha nnel bed with a particular focus on the risk of incision (i.e., down cutting). The decision tree is incl uded in Figure 14. The first step is to assess the channel bed resistance. There are three categories defined as follows:

1. Labile Bed – sand-dominated bed, little resistant substrate.

2. Transitional/Intermediate Bed – bed typica lly characterized by gravel/small cobble, Intermediate level of resistance of the substrate and uncertain potential for armoring.

3. Threshold Bed (Coarse/Armored Bed) – armo red with large cobbles or larger bed material or highly-resistant bed substrate (i.e., bedrock).

Based on the channel photographs in the figures and site invest igation, the bed material and resistance (associated with moderate to dense vegetation) are generally within the transitional/intermediate bed ca tegory. Some bed areas containe d smaller grain sizes typically found in a labile bed. However, Reach 1 and 2 do not meet the criteria of containing loosely- packed material. The material is moderately-p acked with dense vegetation binding the soil, which is a characteristic of a transitional/intermediate bed.

In addition to the material si ze and compaction, there are severa l factors that establish the erodibility of a channel such as the flow rate (i.e., size of the tributary area), grade controls, channel slope, vegetative cover, channel pl anform, etc. The Introdu ction of the SCCWRP Hydromodification Screening Tools: Field Manual identifies several of these factors. When multiple factors influence erodibility, it is a ppropriate to perform the more detailed SCCWRP analysis, which is to analyze a channel according to SCCWRP’s transitional/intermediate bed procedure. This requires the most rigorous steps and will generate the appropriate results given the range of factors that define erodibility. The transitional/intermediate bed procedure takes into account that bed material may fall within the labile category (the bed material size is used in SCCWRP’s Form 3 Figure 4), but other factors may trend towa rds a less erodible condition. Dr.

Eric Stein from SCCWRP, who co-authored th e Hydromodification Screening Tools: Field Manual in the Final Hydromodifica tion Management Plan (HMP), indicated that it would be appropriate to analyze channels with multiple factors that impact erodibili ty using the transitional/intermediate bed procedure. Consequently, this procedure was used to produce more accurate results.

7 Transitional/intermediate beds c over a wide susceptibility/potential response range and need to be assessed in greater detail to develop a weight of evidence for the appropriate screening rating.

The three primary risk factors used to asse ss vertical susceptibility for channels with transitional/intermediate bed materials are:

1. Armoring potential – three states (Checklist 1)

2. Grade control – three states (Checklist 2)

3. Proximity to regionally-calibrated incision/braiding threshold (Screening Index Threshold – Probability Diagram)

These three risk factors are assessed using chec klists and a diagram (see Appendix B), and the results of each are combined to provide a fi nal vertical susceptibility rating for the intermediate/transitional bed-material group. Each checklist and diagram contains a Category A, B, or C rating. Category A is the most resistant to vertical changes while Category C is the most susceptible.

Checklist 1 determines armoring potential of th e channel bed. The natural channel bed along Reach 1 and 2 are assigned to Category B, whic h represents intermediate bed material of unknown resistance or unknown armoring potential due to a surface veneer such as vegetation.

The soil in both reaches was probed and pene tration was relatively difficult through the underlying layer.

Checklist 2 determines grade control characteristics of the channel bed. This is reliant on the spacing of the grade controls. The categories fo r Checklist 2 are related to a grade control spacing of 2/S
v and 4/Sv, where Sv is the valley slope from Appendix A. The 2/Sv and 4/Sv results are in meters, so a factor is applied to convert to feet. A reach is in Category A if it has a maximum grade control spacing of less than 2/S v. A reach is in Category B if it has a maximum spacing between 2/S v and 4/S v. Finally, a reach is in Category C if it has a maximum spacing greater than 4/Sv. Table 2 summarizes the S v, 2/Sv, and 4/Sv values for Reach 1 and 2 along with the maximum grade control spacing within each study reach. The Reach 1 maximum grade control spacing is equal to the length of Reach 1 (1,103 feet) plus Reach 2 (1,637 feet). The Reach 2 maximum grade control sp acing is the length of Reach 2 (1,637 feet). The associated category is also included in Table 2.

Reach S
v,
feet/feet
2/Sv,
feet
4/Sv,
feet
Max. Grade Control
Spacing, feet Category
1 0.00453 1,448 2,895 2,740 B
2 0.00611 1,074 2,148 1,637 B

Table 2. Checklist 2 Values based on Grade Control Spacing

The Screening Index Threshold is a probability di agram that depicts the risk of incising or braiding based on the potential st ream power of the valley rela tive to the median particle 8 diameter. The threshold is based on regional data from Dr. Howard Chang of Chang Consultants and others. The probability diagram is based on d50 as well as the screening index (INDEX) value determined in the initial desktop analysis (s ee Appendix A). The Form 1 results in Appendix A determined an INDEX of 0.0216 for Reach 1 an d 0.0296 for Reach 2. SCCWRP specifies use of a US SAH-97 half-phi template gravelometer to determine d 50 in a natural channel. This gravelometer allows a minimum d 50 measurement of 2 millimeters. The Screening Index Threshold diagram shows that the probability of incising or braiding is less than 50 percent for a d50 of 2 millimeters if the INDEX value is 0.0220 or less. Since the Reach 1 Screening Index values is less than the 50 percent value, Reach 1 is within Category A.

For Reach 2, d
50 had to be determined to assess the Screening Index Threshold since its INDEX value is greater than the smallest 50 percent risk value. d50 can be derived from a pebble count in which a minimum of 100 particles are obtained along transects at the site. SCCRWP states that if fines less than ½-inch thick are at a sample point, it is appropriate to sample the coarser buried substrate. A gravelometer along Reach 2 is included in Figure 13 for reference. The d 50 value is
the particle size in which 50 percent of the part icles are smaller and 50 percent are larger. The pebble count result for Reach 2 is included in Appendix B and show a d 50 of 11 millimeters. The screening index for Reach 2 from Appendix A is 0.0296. Plotting the d 50 and screening index values on the Mobility Index Threshold diagram shows that Reach 2 has a less than 50 percent probability of incising or braiding, so falls within Category A.

The overall vertical rating is determined from th e Checklist 1, Checklist 2, and Mobility Index Threshold results. The scoring is based on the following values:

Category A = 3, Category B = 6, Category C = 9

The vertical rating score is based on these values and the equation:

Vertical Rating = [(ar moring × grade control)
1/2 × screening index score]1/2
= [(6 × 6) 1/2 × 3]1/2
= 4.2 for Reach 1 and 2

Since the vertical rating is less than 4.5, Reach 1 and 2 have a low threshold for vertical susceptibility.

Lateral Stability
The purpose of the lateral decision tree (Figure 6-5 from County of San Diego HMP included in Figure 15) is to assess the state of the channe l banks with a focus on the risk of widening.

Channels can widen from either bank failure or through fluvial a vulsions such as chute cutoffs and braiding. Widening through fl uvial avulsions/active braiding is a relatively straightforward observation. If braiding is not already occurring, the next logical step is to assess the condition of the banks. Banks fail through a variety of mechan isms; however, one of the most important distinctions is whether they fail in mass (a s many particles) or by fluvial detachment of individual particles. Although much research is dedicated to the combined effects of weakening, fluvial erosion, and mass failure, SCCWRP found it valuable to segregat e bank types based on the inference of the dominant failure mechanism (as the management approach may vary based 9 on the dominant failure mechan ism). A decision tree (Form 4 in Appendix B) is used in conducting the lateral susceptibility assessment. Definitions are provided below for terms used in the lateral susceptibility assessment.

The first step in the decision tree is to dete rmine if lateral adjus tments are occurring. The adjustments can take the form of extensive mass wasting (greater than 50 percent of the banks are exhibiting planar, slab, or rotational failures a nd/or scalloping, undermin ing, and/or tension cracks). The adjustments can also involve extensive fluvial erosion (si gnificant and frequent bank cuts on over 50 percent of the banks). Neith er mass wasting nor exte nsive fluvial erosion was evident within Reach 1 or 2 during a field investigation as evidenced by the figures.

The next step in the Form 4 decision tree is to assess the consolidation of the bank material. The banks were moderate to well-consolidated in Reach 1 and 2. This determination was made because the ground surface was difficult to penetrate with a probe. In addition, the banks showed no evidence of crumbling and were composed of relatively well-packed particles.

Form 6 (see Appendix B) is used to assess the probability of mass was ting. Form 6 identifies a 10, 50, and 90 percent probability based on the ba nk angle and bank height. From the site investigation and SANGIS’ 2-foot contour interval topographic mapping, the bank angles in Reach 1 and 2 average 1.5:1 (33.7 degrees) or flatter – most banks are 2:1. Form 6 shows that the probably of mass wasting and bank failure has less than 10 percent risk for a 33.7 degree bank angle or less regardless of the bank height.

The final two steps in the Form 4 decision tree are based on the braiding risk determined from the vertical rating as well as the Valley Width Index (VWI) calculated in Appendix A. If the vertical rating is high, the braiding risk is consid ered to be greater than 50 percent. Excessive braiding can lead to lateral bank failure. For Re ach 1 and 2 the vertical rating is low, so the braiding risk is less than 50 pe rcent. Furthermore, a VWI greater than 2 represents channels unconfined by bedrock or hillslope and, hence, s ubject to lateral migration. The VWI calculation in the spreadsheet in Appendix A shows th at the VWI for Reach 1 (VWI=0.17) and 2 (VWI=1.91) are less than 2.

From the above steps, the latera l susceptibility rating is low fo r both reaches (red circles are included on the Form 4: Lateral Susceptibility Fi eld Sheet decision tree in Appendix B showing the decision path).

CONCLUSION

The SCCWRP channel screening tools were used to assess the downstream channel susceptibility for the NC - Ente rprise Affordable Housing redevelopment project being designed by Stevens Cresto Engineers. The project runoff will be treated and then collected and conveyed north in hardened, non-erodible drainage faciliti es (culvert and RCP) to San Marcos Creek. An assessment was performed for San Marcos Cree k based on office analyses and field work. The results indicate a low threshold for vertical and lateral susceptibilities for Reach 1 and 2

10 The HMP requires that these results be compared with the critical stress calculator results outlined in the County of San Diego HMP. The crit ical stress results are included in Appendix B for the Reach 1 and 2 using the spreadsheet provided by the County. The channel dimensions were estimated from topographic mapping and Google Earth. Based on these values, the critical stress results returned a low threshold for Reach 1 and 2 consistent with the SCCWRP channel screening results. Therefore, the SCCWRP analyses and critical stress calculat or demonstrate that a low overall threshold is applicable to the overall study reach (i.e., 0.5Q 2).

11 Figure 1. Riprap under Inland Rail Trail – Upstream End of Reach 1

Figure 2. Looking Downstream at Reach 1 from Upper End

12 Figure 3. Looking Upstream at Middle of Reach 1

Figure 4. Looking Downstream at Middle of Reach 1

13 Figure 5. Looking Upstream at Lower End of Reach 1 / Upper End of Reach 2 from Sprinter Rail

Figure 6. Reach 2 at Sprinter Rail Crossing - 84” RCP Outlet (POC) at Bottom of Figure

14 Figure 7. Looking Downstream at Reach 2 from Sprinter Rail Crossing

Figure 8. Middle of Reach 2

15 Figure 9. Looking Upstream at Reach 2 from Rancheros Drive

Figure 10. Looking Downstream at Reach 2 from Rancheros Drive

16 Figure 11. Looking Upstream at Reach 2 from Lower End at Concrete Transition Structure

Figure 12. Concrete Transition Structure and Box Culverts below Reach 2

17 Figure 13. Gravelometer in Reach 2

18 Figure 14. SCCWRP Vertical Channel Susceptibility Matrix

19 Figure 15. SCCWRP Lateral Channel Susceptibility Matrix

APPENDIX A

SCCWRP INITIAL DESKTOP ANALYSIS

FORM 1: INITIAL DESKTOP ANALYSIS
Complete all shaded sections.

IF required at multiple locations, circle one of the following site types:

Applicant Site / Upstream Extent / Downstream Extent
Location: Latitude: Longitud e:

De
scription (river name, crossing streets, etc.):

GIS Parameters: The International System of Units (SI) is used throughout the assessment as the field standard and for consistency with the broader scientific community. However, as the singular exception, US Customary units are used for contributing drainage area (A) and mean annual precipitation (P) to apply regional flow equations after the USGS. See SCCWRP Technical Report 607 for example measurements and “Screening Tool Data Entry.xls” for automated calculations.

Form 1 Table 1. Initial d
esktop analysis in GIS.

Symbol Variable Description and Source Value
A Area
(mi2)
Contributing drainage area to screening location via published Hydrologic Unit Codes (HUCs) and/or ≤ 30 m National Elevation Data (NED), USGS seamless server
Watershed
properties
(English units)
P Mean annual
precipitation
(in)
Area-weighted annual precipitation via USGS delineated polygons using records from 1900 to 1960 (which was more significant in hydrologic models than polygons delineated from shorter record lengths) Sv Valley slope
(m/m)
Valley slope at site via NED, measured over a relatively homogenous valley segment as dictated by hillslope configuration, tributary confluences, etc., over a distance of up to ~500 m or 10% of the main- channel length from site to drainage divide
Site properties
(SI units)
Wv Valley width
(m)
Valley bottom width at site between natural valley walls as dictated by clear breaks in hillslope on NED raster, irrespective of potential armoring from floodplain encroachment, levees, etc. (imprecise measurements have negligible effect on rating in wide valleys where VWI is >> 2, as defined in lateral decision tree)
Form 1 Tabl
e 2. Simplif ied peak flo w, screening index, and valley width index. Values for this table should be calculated in the sequence shown in this table, using values from Form 1 Table 1.

Symbol Dependent Variable Equation Required Units Value Q10cfs 10-yr peak flow (ft3/s) Q10cfs = 18.2 * A 0.87 * P 0.77 A (mi2) P (in)
Q10 10-yr peak flow (m3/s) Q10 = 0.0283 * Q10cfs Q10cfs (ft3/s) INDEX 10-
yr screening index (m1.5/s0.5) INDEX = Sv*Q10 0.5 Sv (m/m) Q10 (m3/s)
Wref Reference width (m) W ref = 6.99 * Q10 0.438 Q10 (m3/s) VWI Vall
ey width index (m/m) VWI = Wv/Wref Wv (m)
Wref (m)
(Sheet 1 of 1)
B - 3

33.140727° -117.158380° San Marcos Creek from Inland Rail
Trail to upstream of North Twin Oaks Valley Road.

See attached
Form 1 table
on next page
for calculated
values for each
reach.

See attached
Form 1 table
on next page
for calculated
values for each
reach.

Note: Lat/Long obtained from Google Earth near middle
of study reach.

SCCWRP FORM 1 ANALYSES
Reach
Area
A, sq. mi.

Mean Annual Precip.

P, inches
Valley Slope
Sv, m/m
Valley Width
Wv, m
10-Year Flow
Q10cfs, cfs
10-Year Flow
Q10, cms
1 6.7390 15.85 0.00453 4.6 804 22.7
2 7.0066 15.85 0.00611 53.3 831 23.5
Reach
10-Year Screening Index
INDEX
Reference Width
Wref, m
Valley Width Index
VWI, m/m
1 0.0216 27.5 0.17
2 0.0296 27.9 1.91
StreamStats Report
Collapse All
Basin Characteristics
Parameter Code Parameter Description Value Unit
DRNAREA Area that drains to a point on a stream 6.7390 square miles General Disclaimers
USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.

USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.

USGS Product Names Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Application Version: 4.24.0
StreamStats Services Version: 1.2.22
NSS Services Version: 2.2.1
Region ID: CA
Workspace ID: CA20240915023902654000
Clicked Point (Latitude, Longitude): 33.14147, -117.15679 Time: 2024-09-14 19:39:24 -0700


9/14/24, 7:49 PM StreamStats
https://streamstats.usgs.gov/ss/ 1/1
Reach 1

StreamStats Report
Collapse All
Basin Characteristics
Parameter Code Parameter Description Value Unit
DRNAREA Area that drains to a point on a stream 7.0066 square miles General Disclaimers
USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.

USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.

USGS Product Names Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Application Version: 4.24.0
StreamStats Services Version: 1.2.22
NSS Services Version: 2.2.1
Region ID: CA
Workspace ID: CA20240915020704703000
Clicked Point (Latitude, Longitude): 33.13864, -117.16169 Time: 2024-09-14 19:07:27 -0700


9/14/24, 7:37 PM StreamStats
https://streamstats.usgs.gov/ss/ 1/1
Reach 2

Study Reaches
Rain Gages
Rain Gages

/0/1/2/3/1/2/4/2/5 /6/7/8/9/10/11/12/11/9/13/i255/8/15/16/12/17/9/18/10/12/15/i255/19/i255/8/20/21/22/23/24/25/i255/7/26/22/22/23/27/28 /29/24/24/30/31/32/1/1/33/27/34/34/35/36/27/21/35/25/36/26/1/34/37/21/19/38/21/39/1/34/20/21/40/15/12/10/35/30/20/41/34/23/2/42/43/2 /5/1/5 /44/45/46/47/48/49/50/49/47/51/i255/46/53/54/50/55/47/56/48/50/53/i255/57/58/59/60/61/62/60/63 /64/65/66/67/68/69/i255/68/70/i255/56/65/71/68/66/69/i255/72/68/73/74/75/76/77/i255/46/76/67/78/79/74/65/i255/45/80/78/78/79/66/77 /64/65/66/67/68/69/i255/68/70/i255/56/65/71/68/66/69/i255/81/i255/82/60/83/58/82/83/82/61/84/85/i255/74/68/i255/58/85/83/85/82/83/82/84/86/84 /87/88/89/90 /91/92/93 /88/94/95/96/94/93 /88/97/87/98/89/87 /98/99/95 /98/100/101/91/96/102/103/104/105/106/107/108/91/103/95/89/89/98/88/99 /95/107/91/94/88/100/91/i255/93/88/110/111/i255/112/91/113/96/91/94/88/104/98/94/91/i255/114/90/115/116/117/111/118/116/116/111/119/116/120/111/120/121/122/111/122/121/116/111/123/120/122/111/124/120/120/111/122/120/120/111/122/120/125/111/121/121/118/111/124/121/122/111/118/116/116/111/125/121/125/111/118 /95/107/91/94/88/100/91/i255/93/126/89/111/i255/112/91/113/96/91/94/88/104/98/94/91/i255/114/90/115/119/121/111/123/119/118/111/121/117/122/111/117/117/116/111/124/125/124/111/125/125/117/111/124/125/120/111/124/125/120/111/116/125/125/111/123/117/120/111/121/117/123/111/122/119/121/111/117/117/121/111/117 /95/107/91/94/88/100/91/i255/112/106/104/88/99/i255/127/94/91/103/126/96/126/104/88/104/126/106/89 /114/126/89/111/115 /119/111/122/117/119/111/123/123/122/111/116/120/123/111/119/122/124/111/117/121/124/111/124/118/124/111/124/119/124/111/123/119/124/111/122/119/124/111/121/124/123/111/125/117/122/111/116/121/123/116/111/122/122 /95/107/91/94/88/100/91/i255/112/106/104/88/99/i255/101/89/106/128/90/88/99/99/i255/114/126/89/111/115/124 /111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124/124/111/124 /95/107/91/94/88/100/91/i255/101/89/106/128/i255/108/91/96/104/129/i255/114/126/89/111/115/105 /106/108/88/104/88 /127/91/94/103/91/89/104/i255/106/130/i255/96/106/131/131/126/92/99/91/i255/106/92/131/91/94/107/88/104/126/106/89/131/i255/130/106/94/i255/96/91/94/126/106/132/i255/106/130/i255/94/91/103/106/94/132/111 /i255/93/88/110/111/i255/112/91/113/96/111/133/i255/118/118/111/121/134/i255/93/126/89/111/i255/112/91/113/96/111/133/i255/118/118/111/121/134/i255/127/94/91/103/126/96/126/104/88/104/126/106/89/133/i255/118/118/111/121/134/i255/101/89/106/128/130/88/99/99/133/i255/116/119/111/116/134/i255/101/89/106/128/i255/108/91/96/104/129/133/i255/116/119/111/125/134/i255 /i255/135/129/91/103/136/i255/101/104/88/104/126/106/89/i255/93/91/104/88/132/88/104/88/i255/106/94/i255/93/91/104/88/132/88/104/88/i255/100/94/88/96/129/126/103/131/i255/130/106/94/i255/113/106/94/91/i255/132/91/104/88/126/99/i255/88/92/106/98/104/i255/132/88/104/88/i255/103/106/113/96/99/91/104/91/89/91/131/131/111 /137/138/139/140/138/141/142/i255/144/138/145/146/147/142/148/149/i255/150/149/146/151/148/140/138/i255/150/138/142/140/138/141/152/i255/153/141/154/154/155/156/141/146/157/138/156/158

/0/1/2/3/1/2/4/2/5 /6/7/8/9/10/11/12/11/9/i255/2/14/i255/8/15/16/12/17/9/18/10/12/15/i255/19/i255/8/20/21/22/23/24/25/i255/7/26/22/22/23/27/28 /29/24/24/30/31/32/1/1/33/27/34/34/35/36/27/21/35/25/36/26/1/34/37/21/19/38/21/39/1/34/20/21/40/15/12/10/35/30/20/41/34/23/2/42/43/44 /5/1/5 /45/46/47/48/49/50/51/50/48/i255/53/54/i255/47/55/56/51/57/48/58/49/51/55/i255/59/60/61/53/62/63/64/65 /66/67/68/69/70/71/i255/70/72/i255/58/67/73/70/68/71/i255/74/70/75/76/77/78/79/i255/47/78/69/80/81/76/67/i255/46/82/80/80/81/68/79 /66/67/68/69/70/71/i255/70/72/i255/58/67/73/70/68/71/i255/83/i255/84/85/i255/86/85/86/87/88/87/i255/76/70/i255/64/85/53/88/85/53/60/86/64 /89/90/91/92 /93/94/95 /90/96/97/98/96/95 /90/99/89/100/91/89 /100/101/97/100/102/103/93/98/104/105/106/107/108/109/110/93/105/97/91/91/100/90/101 /97/109/93/96/90/102/93/i255/95/90/112/113/i255/114/93/115/98/93/96/90/106/100/96/93/i255/116/92/117/118/119/113/120/118/119/113/120/121/120/113/122/121/123/113/124/121/118/113/118/125/126/113/120/125/121/113/126/125/125/113/118/125/118/113/118/121/119/113/119/121/122/113/122/118/125/113/119/121/121/113/126 /97/109/93/96/90/102/93/i255/95/127/91/113/i255/114/93/115/98/93/96/90/106/100/96/93/i255/116/92/117/123/122/113/128/123/123/113/123/123/121/113/128/124/120/113/123/124/123/113/118/124/125/113/128/118/126/113/128/118/122/113/122/118/128/113/123/124/124/113/126/123/118/113/118/123/128/113/125/124/126/113/122 /97/109/93/96/90/102/93/i255/114/108/106/90/101/i255/129/96/93/105/127/98/127/106/90/106/127/108/91 /116/127/91/113/117 /122/113/120/120/122/113/123/118/126/113/121/128/128/113/128/123/120/113/126/118/120/113/128/126/120/113/120/125/120/113/120/125/120/113/126/120/120/113/121/123/128/113/122/122/128/113/125/126/128/123/113/119/122 /97/109/93/96/90/102/93/i255/114/108/106/90/101/i255/103/91/108/130/92/90/101/101/i255/116/127/91/113/117/120 /113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120/120/113/120 /97/109/93/96/90/102/93/i255/103/91/108/130/i255/110/93/98/106/131/i255/116/127/91/113/117 /120/120/120/120/120/120/120/120/120/120/120/120/120 /129/93/96/105/93/91/106/i255/108/132/i255/98/108/133/133/127/94/101/93/i255/108/94/133/93/96/109/90/106/127/108/91/133/i255/132/108/96/i255/98/93/96/127/108/134/i255/108/132/i255/96/93/105/108/96/134/113 /i255/95/90/112/113/i255/114/93/115/98/113/135/i255/119/121/113/118/136/i255/95/127/91/113/i255/114/93/115/98/113/135/i255/119/121/113/128/136/i255/129/96/93/105/127/98/127/106/90/106/127/108/91/135/i255/119/121/113/121/136/i255/103/91/108/130/132/90/101/101/135/i255/119/125/113/128/136/i255/103/91/108/130/i255/110/93/98/106/131/135/i255/119/125/113/128/136/i255 /i255/137/131/93/105/138/i255/103/106/90/106/127/108/91/i255/95/93/106/90/134/90/106/90/i255/108/96/i255/95/93/106/90/134/90/106/90/i255/102/96/90/98/131/127/105/133/i255/132/108/96/i255/115/108/96/93/i255/134/93/106/90/127/101/i255/90/94/108/100/106/i255/134/90/106/90/i255/105/108/115/98/101/93/106/93/91/93/133/133/113 /139/140/141/142/140/143/144/i255/146/140/147/148/149/144/150/151/i255/152/151/148/153/150/142/140/i255/152/140/144/142/140/143/154/i255/155/143/156/156/157/158/143/148/159/140/158/160

APPENDIX B

SCCWRP FIELD SCREENING DATA
Form 3 Support Materials
Form 3 Checklists 1 and 2, along with information recording in Form 3 Table 1, are intended to support the decisions pathways illustrated in Form 3 Overall Vertical Rating for Intermediate/Transitional Bed.

Form 3 Checklist 1: Armoring Potential
□ A A mix of coarse gravels and cobbles that are tightly packed with <5% surface material of diameter <2 mm
□ B
Intermediate to A and C or hardpan of unknown resistance, spatial extent (longitudinal and depth), or unknown armoring potential due to surface veneer covering gravel or coarser layer encountered with probe □ C
Gravels/cobbles that are loosely pa cked or >25% surface material of diameter <2 mm
Form 3 Figure 2. Armoring potential photographic supplement for ass essing intermediate beds
(16 < d50 < 128 mm) to be used in conjunction with Form 3 Checklist 1. (Sheet 2 of 4)
B - 7
REACH 1 AND 2 RESULTS
x

Form 3 Checklist 2: Grade Control
□ A Grade control is present with spacing <50 m or 2/Sv m  No evidence of failure/ineffectiveness, e.g., no headcutting (>30 cm), no active mass wasting (analyst cannot say grade control sufficient if mass- wasting checklist indicates presence of bank failure), no exposed bridge pilings, no culverts/structures undermined
 Hard points in serviceable condition at decadal time scale, e.g., no apparent undermining, flanking, failing grout
 If geologic grade control, rock should be resistant igneous and/or metamorphic; For sedimentary/hardpan to be classified as ‘grade control’, it should be of demonstrable strength as indicated by field testing such as hammer test/borings and/or inspected by appropriate stakeholder □ B Intermediate
to A and C – artificial or geologic grade control present but spaced 2/Sv m to 4/Sv m or potential evidence of failure or hardpan of uncertain resistance
□ C Grad
e control absent, spaced >100 m or >4/S v m, or clear evidence of ineffectiveness
B - 8
Form 3 Figure 3. Grade-control (condition) photographic supplement for assessing intermediate beds (16 < d50 < 128 mm) to be used in conjunction with Form 3 Checklist 2. (Sheet 3 of 4)
REACH 1 AND 2 RESULTS
x

Regionally-Calibrated Screening Index Threshold for Incising/Braiding For transitional bed channels (d50 between 16 and 128 mm) or labile beds (channel not incised past critical bank height), use Form 3 Figure 3 to determine Screening Index Score and complete Form 3 Table 1.

Form 3 Figure 4. Probability of incising/braiding based on logistic regression of Screening Index and d50 to be used in conjunction with Form 3 Table 1.

Form 3 Table 1. Values for Screening Index Threshold (probability of incising/braiding) to be used in conjunction w
ith Form 3 Figure 4 (above) to complete Form 3 Overall Vertical Rating for Intermediate/Transitional Bed (below).. Screening Index Score: A = <50% probability of incision for current Q10, valley slope, and d50; B = Hardpan/d50 indeterminate; and C = >50% probability of incising/braiding for current Q10, valley slope, and d50. d50 (mm)
From Form 2
Sv*Q10

0.5 (m1.5/s0.5)
From Form 1
Sv*Q10

0.5 (m1.5/s0.5)
50% risk of incising/braiding
from table in Form 3 Figure 3 above
Screening Index Score
(A, B, C)
Overall Vertical Rating for Intermediate/Transitional Bed Calculate the overall Vertical Rating for Transitional Bed channels using the formula below.

Numeric values for responses to Form 3 Checklists and Table 1 as follows: A = 3, B = 6, C = 9.

Vertical Susceptibility based on Vertical Rating: <4.5 = LOW;

4.5 to 7 = MEDIUM; and >7 = HIGH.

B - 9
(Sheet 4 of 4)
REACH 1 AND 2 RESULTS
6 x 6 x 3 = 4.2
Reach 1 = 0.216
Reach 2
PEBBLE COUNT REACH 2
# Reach 2 Diameter, mm
12 22
32 42
52 62
72 82
92 10 2.8
11 2.8
12 2.8
13 2.8
14 2.8
15 2.8
16 2.8
17 2.8
18 2.8
19 4
20 4
21 4
22 4
23 4
24 4
25 4
26 4
27 4
28 4
29 4
30 4
31 4
32 4
33 5.6
34 5.6
35 5.6
36 5.6
37 5.6
38 5.6
39 5.6
40 5.6
41 5.6
42 5.6
43 8
44 8
# Reach 2 Diameter, mm
45 8
46 8
47 8
48 8
49 11
50 11 D50
51 11
52 11
53 11
54 11
55 11
56 11
57 11
58 11
59 11
60 11
61 11
62 11
63 16
64 16
65 16
66 16
67 16
68 16
69 16
70 16
71 16
72 16
73 16
74 16
75 16
76 16
77 16
78 16
79 16
80 16
81 16
82 16
83 16
84 16
85 22.6
86 22.6
87 22.6
88 22.6
89 22.6
90 22.6
# Reach 2 Diameter, mm
91 22.6
92 22.6
93 22.6
94 22.6
95 32
96 32
97 32
98 32
99 32
100 32
FORM 4: LATERAL SUSCEPTIBILTY FIELD SHEET
Lateral Screening Forms
Circle appropriate nodes/pathway for proposed site
OR use sequence of questions provided in Form 5.
(Sheet 1 of 1)
B - 10
REACH 1 AND 2 RESULTS

FORM 6: PROBABILITY OF MASS WASTING BANK FAILURE
If mass wasting is not currently extensive and the banks are moderately- to well-consolidated, measure bank height and angle at several locations (i.e., at least three locations that capture the range of conditions present in the study reach) to estimate representative values for the reach. Use Form 6 Figure 1 below to determine if risk of bank failure is >10% and complete Form 6 Table 1. Support your results with photographs that include a protractor/rod/tape/person for scale.

Bank Angle
(degrees)
(from Field)
Bank Height

(m)
(from Field)
Corresponding Bank Height for
10% Risk of Mass Wasting (m)
(from Form 6 Figure 1 below)
Bank Failure Risk
(<10% Risk)
(>10% Risk)
Left Bank
Right Bank
Form 6 Figure 1. Probability Mass Wasting diagram, Bank Angle:Height/% Risk table, and
Band Height:Angle schematic.

B - 12
(Sheet 1 of 1)
REACH 1 AND 2 RESULTS

33.7 degrees (1.5:1) --- --- <10%

33.7 degrees (1.5:1) --- --- <10%

Critical Flow Calculator Reach 1
enter all values in green cells
and drop down boxes
Inputs
a) Receiving channel width at top of
bank (ft) - see figure on right

50.0 b) Channel width at bed (ft) 15.0
c) Bank height at top of bank (ft) 10.0
Channel gradient (ft/ft) 0.00453
Receiving channel roughness
Channel materials (use weakest of
bed or banks). If materials are varied
use weakest material covering more
than 20% of channel.

Mean bed particle size (mm) 38.5 Critical shear stress for d50 lb/sq ft 0.6 Select method of calculating Q2
Q2 for receiving water (cfs) 10.0
Pre-development Q2 for project site 6.8
Receiving water watershed annual
precip (inches)

15.85 Receiving water watershed
area at PoC (sq mi)

6.7390
Project watershed annual
precipitation (inches)

15.85 Project watershed area
draining to PoC (sq mi)

6.7390
Outputs - Flow control range
Receiving water Q2 48.6
Point of Compliance low
flow rate (cfs) 24.3
Project site Q2 48.6 Low flow class 0.5Q2
Channel vulnerability Low
a
b
c

Critical Flow Calculator Reach 2
enter all values in green cells
and drop down boxes
Inputs
a) Receiving channel width at top of
bank (ft) - see figure on right
250.0
b) Channel width at bed (ft) 175.0
c) Bank height at top of bank (ft) 10.0
Channel gradient (ft/ft) 0.00611
Receiving channel roughness
Channel materials (use weakest of
bed or banks). If materials are varied
use weakest material covering more
than 20% of channel.

Mean bed particle size (mm) 38.5 Critical shear stress for d50 lb/sq ft 0.6 Select method of calculating Q2
Q2 for receiving water (cfs) 10.0
Pre-development Q2 for project site 6.8
Receiving water watershed annual
precip (inches)

15.85 Receiving water watershed
area at PoC (sq mi)

7.0066
Project watershed annual
precipitation (inches)

15.85 Project watershed area
draining to PoC (sq mi)

7.0066
Outputs - Flow control range
Receiving water Q2 50.0
Point of Compliance low
flow rate (cfs) 25.0
Project site Q2 50.0 Low flow class 0.5Q2
Channel vulnerability Low
a
b
c

Attachment 2d

Flow Control Facility Design and Structural BMP Drawdown Calculations

N/A WILL BE PROVIDED AT FINAL ENGINEERING
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
ATTACHMENT 3
Structural BMP Maintenance Information

This is the cover sheet for Attachment 3.

Indicate which Items are Included behind this cover sheet:

Attachment
Sequence
Contents Checklist
Attachment 3a Structural BMP Maintenance Thresholds
and Actions (Required)

 Included

Attachment 3b Draft Maintenance Agreement (when
applicable)
 Included
 N/A – WILL BE PROVIDED AT FINAL

ENGINEERING

City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
Use this checklist to ensure the required information has been included in the Structural BMP Maintenance Information Attachment:

 Preliminary Design / Planning / CEQA level submittal:

Attachment 3a must identify:

 Typical maintenance indicators and actions for proposed structural BMP(s) based on Section 7.7 of the BMP Design Manual

Attachment 3b is not required for preliminary design / planning / CEQA level submittal.

 Final Design level submittal:

Attachment 3a must identify:

 Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect actual proposed components of the structural BMP(s)
 How to access the structural BMP(s) to inspect and perform maintenance  Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds)
 Manufacturer and part number for proprietary parts of structural BMP(s) when applicable  Maintenance thresholds specific to the structural BMP(s), with a location-specific frame of reference (e.g., level of accumulated materials that triggers removal of the materials, to be identified based on viewing marks on silt posts or measured with a survey rod with respect to a fixed benchmark within the BMP)
 Recommended equipment to perform maintenance
 When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management

Attachment 3b: For private entity operation and maintenance, Attachment 3b shall include a draft maintenance agreement in the local jurisdiction's standard format (PDP applicant to contact the [City Engineer] to obtain the current maintenance agreement forms).

*NOTE: EXHIBITS ARE PRELIMINARY. FINAL EXHIBITS WILL BE PROVIDED AT FINAL ENGINEERING *NOTE: EXHIBITS ARE PRELIMINARY. FINAL EXHIBITS WILL BE PROVIDED AT FINAL ENGINEERING STORMCAPTURE®
Inspection and Maintenance Guide

Description
The StormCapture® system is an underground, modular, structural precast concrete storage system for stormwater detention, retention, infiltration, harvesting and reuse, and water quality volume storage. The system’s modular design utilizes multiple standard precast concrete units with inside dimensions of 7 feet by 15 feet (outside dimensions of 8 feet by 16 feet) to form an underground storage system. The inside height of the StormCapture system can range from 2 feet to 14 feet. This modular design provides limitless configuration options for site- specific layouts.

StormCapture components can be provided as either open-bottom modules to promote infiltration or closed- bottom modules for detention. In some cases, StormCapture modules can be placed in a checkerboard configuration for an even more efficient design. A Link Slab, with a footprint of 9 feet by 17 feet, is then used to bridge each space without a module.

The standard StormCapture design incorporates lateral and longitudinal passageways between modules to accommodate internal stormwater conveyance throughout the system. These passageways may be classified as either a “window configuration” with standard 12-inch tall sediment baffles extending up from the floor of the module to the bottom of the window, or a “doorway configuration” without the sediment baffles. The function and drainage rate of a StormCapture system depends on site-specific conditions and requirements.

Stormwater typically enters the StormCapture system through an inlet pipe. Grated inlets can also be used for direct discharge into the system. The StormCapture system is rated for H-20 traffic loading with limited cover.

Higher load requirements can also be accommodated. In addition, StormCapture systems are typically equipped with a limited number of maintenance modules that provide access to the system for ongoing inspection and maintenance.

Function
The StormCapture system is primarily used to manage water quantity by temporarily storing stormwater runoff from impervious surfaces to prevent flooding, slow down the rate at which stormwater leaves the site, and reduce receiving stream erosion. In addition, the StormCapture system can be used to capture stormwater runoff for water quality treatment. Regardless of how the StormCapture system is used, some sedimentation may occur in the modules during the time water is stored.

Configurations
The configuration of the StormCapture systems may vary, depending on the water quality and/or quantity requirements of the site. StormCapture configurations for detention, retention/infiltration, and retention/ harvesting are described below.

Detention
StormCapture Detention systems are designed with a closed bottom to detain stormwater runoff for controlled discharge from the site. This design may incorporate a dead storage sump and a permanent pool of water if the outlet pipe is higher than the floor elevation. Discharge from the system is typically controlled by an outlet orifice and/or outlet weir to regulate the rate of stormwater leaving the system. StormCapture Detention systems are typically designed with silt-tight joints, however when conditions exist that require a StormCapture system to be watertight, the system may be wrapped in a continuous, impermeable geomembrane liner. If the StormCapture Detention system includes Link Slabs, a liner must be used to detain water since the chambers under each Link Slab have no floor slab. In this case, care must be taken by maintenance personnel not to damage the exposed liner beneath each Link Slab.
2 3
Retention/Infiltration
StormCapture Retention/Infiltration systems are designed with an open bottom to allow for the retention of stormwater onsite through infiltration into the base rock and surrounding soils. For infiltration systems, the configuration of the base of the StormCapture system may vary, depending on the needs of the site and the height of the system. Some systems may use modules that have fully open bottoms with no concrete floor, while other systems may use modules that incorporate floor openings in the base of each module. These are typically 24-inch by 24-inch openings. For open-bottom systems, concrete splash pads may be installed below inlet grate openings and pipe inlets to prevent erosion of base rock. A StormCapture Infiltration system may have an elevated discharge pipe for peak overflow.

Retention/Harvesting
StormCapture Retention/Harvesting systems are similar to detention systems using closed-bottom modules, but stormwater is typically retained onsite for an extended period of time and later reused for non-potable applications or irrigation. For rainwater harvesting systems, an impermeable geomembrane liner is typically installed around the modules to provide a water-tight system.

Inspection and Maintenance Overview
State and local regulations typically require all stormwater management systems to be inspected on a regular basis and maintained as necessary to ensure performance and protect downstream receiving waters. Inspections should be used to evaluate the conditions of the system. Based on these inspections, maintenance needs can be determined. Maintenance needs vary by site and system. Using this Inspection & Maintenance Guide, qualified maintenance personnel should be able to provide a recommendation for maintenance needs. Requirements may range from minor activities such as removing trash, debris or pipe blockages to more substantial activities such as vacuuming and removal of sediment and/or non-draining water. Long-term maintenance is important to the operation of the system since it prevents excessive pollutant buildup that may limit system performance by reducing the operating capacity and increasing the potential for scouring of pollutants during periods of high flow.

Only authorized personnel shall inspect and/or enter a StormCapture system. Personnel must be properly trained and equipped before entering any underground or confined space structure. Training includes familiarity with and adherence to any and all local, state and federal regulations governing confined space access and the operation, inspection, and maintenance of underground structures.

Inspection and Maintenance Frequency
The StormCapture system should be inspected on a regular basis, typically twice per year, and maintained as required. The maintenance frequency will be driven by the amount of runoff and pollutant loading encountered by a given system. Local jurisdictions may also dictate inspection and maintenance frequencies. 4 Inspection Equipment
The following equipment is helpful when conducting StormCapture inspections:
• Recording device (pen and paper form, voice recorder, iPad, etc.) • Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) • Traffic control equipment (cones, barricades, signage, flagging, etc.) • Manhole hook or pry bar
• Confined space entry equipment, if needed
• Flashlight
• Tape measure
• Measuring stick or sludge sampler
• Long-handled net (optional)
Inspection Procedures
A typical StormCapture system provides strategically placed access points that may be used for inspection.

StormCapture inspections are usually conducted visually from the ground surface, without entering the unit. This typically limits inspection to the assessment of sediment depth, water drain down, and general condition of the modules and components, but a more detailed assessment of structural condition may be conducted during a maintenance event.

To complete an inspection, safety measures including traffic control should be deployed before the access covers are removed. Once the covers have been removed, the following items should be inspected and recorded (see form provided at the end of this document) to determine whether maintenance is required:
• Observe inlet and outlet pipe penetrations for blockage or obstruction. • If possible, observe internal components like baffles, flow control weirs or orifices, and steps or ladders to determine whether they are broken, missing, or possibly obstructed. • Observe, quantify, and record the sediment depths within the modules. • Retrieve as much floating trash as possible with a long-handled net. If a significant amount of trash remains, make a note in the Inspection & Maintenance Log.
• For infiltration systems, local regulations may require monitoring of the system to ensure drain down is occurring within the required permit time period (typically 24 to 72 hours). If this is the case, refer to local regulations for proper inspection procedure.

Maintenance Indicators
Maintenance should be scheduled if any of the following conditions are identified during the inspection:
• Inlet or outlet piping is blocked or obstructed.
• Internal components are broken, missing, or obstructed. • Accumulation of more than six inches of sediment on the system floor or in the sump, if applicable. • Significant accumulation of floating trash and debris that cannot be retrieved with a net. • The system has not drained completely after it hasn’t rained for one to three days, or the drain down does not meet permit requirements.
• Any hazardous material is observed or reported.
5 Maintenance Equipment
The following equipment is helpful when conducting StormCapture maintenance:
• Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) • Traffic control equipment (cones, barricades, signage, flagging, etc.) • Manhole hook or pry bar
• Confined space entry equipment, if needed
• Flashlight
• Tape measure
• Vacuum truck
Maintenance Procedures
Maintenance should be conducted during dry weather when no flow is entering the system. Confined space entry is usually required to maintain the StormCapture. Only personnel that are OSHA Confined Space Entry trained and certified may enter underground structures. Once safety measures such as traffic control have been deployed, the access covers may be removed and the following activities may be conducted to complete maintenance:
• Remove trash and debris using an extension on the end of the boom hose of the vacuum truck. Continue using the vacuum truck to completely remove accumulated sediment. Some jetting may be necessary to fully evacuate sediment from the system floor or sump. Jetting is acceptable in systems with solid concrete floors or base slabs (referred to as closed-bottom systems). However, jetting is not recommended for open-bottom systems with a gravel foundation since it may cause bedding displacement, undermining of the foundation, or internal disturbance.
• All material removed from the system during maintenance must be disposed of in accordance with local regulations. In most cases, the material may be handled in the same manner as disposal of material removed from sumped catch basins or manholes.
• Inspect inlet and outlet pipe penetrations for cracking and other signs of movement that may cause leakage. • Inspect the concrete splash pads (applicable for open-bottom systems only) for proper function and placement.
• Inspect the system for movement of modules. There should be less than 3/4-inch spacing between modules.
• Inspect the general interior condition of modules for concrete cracking or deterioration. If the system consists of horizontal joints as part of the modules, inspect those joints for leakage, displacement or deterioration.

Be sure to securely replace all access covers, as appropriate, following inspection and/or maintenance. If the StormCapture modules or any of the system components show significant signs of cracking, spalling, or deterioration or if there is evidence of excessive differential settlement between modules, contact Oldcastle Infrastructure at 800-579-8819.

StormCapture
Inspection & Maintenance Log
Refer to as-built records for details about system size and location onsite Location
Inspection Date
Condition of Internal Components Notes:

Good Damaged Missing
Detention Infiltration Retention/Harvesting
Inlet or Outlet Blockage or Obstruction
System Configuration:

Notes:

Yes No
Trash and Debris Accumulation
Sediment Depth Observed
Notes:

Significant Not Significant
Drain Down Observations Notes:

Appropriate Time Frame Inappropriate Time Frame
Maintenance Requirements
Yes - Schedule Maintenance No - Inspect Again in _______ Months Notes:

Inches of Sediment: ___________

45.0"
(1143 mm)
Storm Tech M C -3500 C ham ber (not to scale)
N om inal C ham ber Specifications
Size (L x W x H) 90 " (2 2 86 m m ) x 77” (1956 m m ) x 45" (1143 m m ) Cham ber Storage 10 9.9 ft 3 (3.11 m 3)
M in. Installed Storage* 178.9 ft 3 (5.0 6 m 3)
W eight 134 lbs (60 .8 kg)
Shipping
15 cham bers/pallet
7 end caps/pallet
7 pallets/truck
Storm Tech M C -3500 End C ap (not to scale)
N om inal End C ap Specifications
Size (L x W x H) 2 5.7" (653 m m ) x 75" (190 5 m m ) x 45" (1143 m m ) End Cap Storage 14.9 ft 3 (0 .42 m 3)
M in. Installed Storage* 46.0 ft 3 (1.30 m 3)
W eight 49 lbs (2 2 .2 kg)
* This assum es a m inim um of 1 2 " (3 05 m m ) of stone above, 9" (2 2 9 m m ) of stone below cham bers, 9" (2 2 9 m m ) of row spacing, and 40% stone porosity. * This assum es a m inim um of 1 2 ” (3 05m m ) of stone above, 9” (2 2 9 m m ) of stone below, 9” (2 2 9 m m ) row spacing, 6” (1 52 m m ) of stone perim eter, and 40% stone porosity.

Storm Tech
M C-3500 Cham ber
Designed to m eet the m ost stringent industry
perform ance standards for superior struc -
tural integrity w hile providing designers
w ith a cost-effective m ethod to save
valuable land and protect w ater
resources. The Storm Tech system
is designed prim arily to be used
under parking lots thus m axim iz -
ing land usage for com m ercial
and m unicipal applications.

MC-3500 Chamber

General Cross Section
NOTE : Assum es 40% porosity for the stone plus the cham ber/end cap volum e. End Cap volum e assum es 6” (152m m ) stone perim eter.

Storage Volum e Per Cham ber/End Cap ft 3 (m 3)
Bare Cham ber/End Cap and Stone
Unit Volum e — Stone Foundation
Storage Depth in. (m m )
ft 3 (m 3) 9 (229) 12 (305) 15 (381) 18 (457)
M C-3500 Cham ber 1 09.9 (3 .1 1 ) 1 78.9 (5.06) 1 84.0 (5.2 1 ) 1 89.2 (5.3 6) 1 94.3 (5.5) M C-3500 End Cap 1 4.9 (0.42 ) 46.0 (1 .3 3 ) 47.7 (1 .3 5) 49.4 (1 .40) 51 .1 (1 .45 ) Am ount of Stone Per Cham ber
NOTE : Assum es 12" (305 m m ) of stone above, and 9" (229 m m ) row spacing, and 6” (152m m ) of perim eter stone in front of end caps.

ENGLISH
Stone Foundation Depth
tons (yd 3) 9 in. 12 in. 15 in. 18 in.

M C-3500 9.1 (6.4) 9.7 (6.9) 1 0.4 (7.3 ) 1 1 .1 (7.8) End Cap 4.1 (2 .9) 4.3 (3 .0) 4.5 (3 .2 ) 4.7 (3 .3 ) M ETRIC kg (m 3) 229 m m 305 m m 381 m m 457 m m
M C-3500 82 2 0 (4.9) 883 1 (5.3 ) 9443 (5.6) 1 0054 (6.0) End Cap 3 699 (2 .2 ) 3 900 (2 .3 ) 41 00 (2 .4) 43 01 (2 .6) Volum e of Excavation Per Cham ber/End Cap in yd 3 (m 3) NOTE: Assum es 9" (229 m m ) of separation betw een cham ber row s, 6" (152 m m ) of perim eter in front of end caps, and 24” (610 m m ) of cover. The volum e of excavation w ill vary as depth of cover increases.

Stone Foundation Depth in. (m m )
9 (229) 12 (305) 15 (381) 18 (457)
M C-3500 1 2 .4 (9.5) 1 2 .8 (9.8) 1 3 .3 (1 0.2 ) 1 3 .8 (1 0.5) End Cap 4.1 (3 .1 ) 4.2 (3 .2 ) 4.4 (3 .3 ) 4.5 (3 .5) AD S “Term s and C onditions of Sale” are available on the AD S w ebsite, w ww.ads-pipe.com .

Advanced D rainage System s, the AD S logo, and the green stripe are registered tradem arks of Advanced Drainage System s.

Storm Tech ® is a registered tradem ark of Storm Tech, Inc The G reen Building C ouncil M em ber logo is a registered tradem ark of the U .S. Green Building Council.

S1 50909 03 /2 01 4
© 2 01 4 Advanced D rainage System s, Inc.

Printed on recycled paper
70 Inwood Road, Suite 3 Rocky Hill Connecticut 06067 860.52 9.81 88 888.892 .2 694 fax 866.3 2 8.8401 fax 860-52 9-8040 www.storm tech.com Detention • Retention • Water Quality
A division of
25 9.0 Inspection and Maintenance
Flamp (Flared End Ramp)
A typical JetVac truck (This is not a StormTech
product.)
Examples of culvert cleaning nozzles appropriate
for Isolator Row Plus maintenance. (These are not
StormTech products).

9.1 Isolator Row Plus Inspection
Regular inspection and maintenance are essential to
assure a properly functioning stormwater system.

Inspection is easily accomplished through the
manhole or optional inspection ports of an Isolator
Row Plus. Please follow local and OSHA rules for a
confined space entry.

Inspection ports can allow inspection to be
accomplished completely from the surface without
the need for a con- fined space entry. Inspection
ports provide visual access to the system with the
use of a flashlight. A stadia rod may be inserted to
determine the depth of sediment. If upon visual
inspection it is found that sediment has accumulated
to an average depth exceeding 3” (76 mm), cleanout
is required.

A StormTech Isolator Row Plus should initially be
inspected immediately after completion of the
site’s construction. While every effort should
be made to prevent sediment from entering the
system during construction, it is during this time
that excess amounts of sediments are most likely
to enter any stormwater system. Inspection and
maintenance, if necessary, should be performed
prior to passing responsibility over to the site’s
owner. Once in normal service, a StormTech Isolator
Row Plus should be inspected bi-annually until
an understanding of the sites characteristics is
developed. The site’s maintenance manager can
then revise the inspection schedule based on
experience or local requirements.

9.2 Isolator Row Plus Maintenance
JetVac maintenance is recommended if sediment
has been collected to an average depth of 3” (76
mm) inside the Isolator Row Plus. More frequent
maintenance may be required to maintain minimum
flow rates through the Isolator Row Plus. The
JetVac process utilizes a high pressure water nozzle
to propel itself down the Isolator Row Plus while
scouring and suspending sediments. As the nozzle is
retrieved, a wave of suspended sediments is flushed
back into the manhole for vacuuming. Most sewer
and pipe maintenance companies have vacuum/
JetVac combi- nation vehicles. Fixed nozzles designed
for culverts or large diameter pipe cleaning are
preferable. Rear facing jets with an effective spread
of at least 45” (1143 mm) are best. StormTech
recommends a maximum nozzle pressure of 2000
psi be utilized during cleaning. The JetVac process
shall only be performed on StormTech Rows that
have ADS Plus fabric over the foundation stone.

A Flamp (flared end ramp) is attached to the inlet
pipe on the inside of the chamber end cap to
provide a smooth transition from pipe invert to
fabric bottom. It is configured to improve chamber
function performance over time by distributing
sediment and debris that would otherwise collect at
the inlet. It also serves to improve the fluid and solid flow back into the inlet pipe during maintenance
and cleaning, and to guide cleaning and inspection
equipment back into the inlet pipe when complete.

ADS “Terms and Conditions of Sale” are available on the ADS website, www.adspipe.com Advanced Drainage Systems, the ADS logo and the Green Stripe are registered trademarks of Advanced Drainage Systems, Inc.

StormTech® and the Isolator® Row Plus are registered trademarks of StormTech, Inc. © 2024 Advanced Drainage Systems, Inc. #11116 5/24 CS StormTech provides state-of-the-art products and services that meet or exceed industry performance standards and expectations. We offer designers, regulators, owners and contractors the highest quality products and services for stormwater management that Saves Valuable Land and Protects Water Resources.

A Family of Products and Services for the Stormwater Industry:
adspipe.com
800-821-6710
MC-3500, MC-4500 and MC-7200 Chambers and End Caps
SC-160LP, SC-310, SC-740 & SC-800 Chambers & End Caps
DC-780 Chambers and End Caps
Fabricated End Caps
Fabricated Manifold Fittings
Patented Isolator Row PLUS for Maintenance and Water Quality Chamber Separation Spacers
In-House System Layout Assistance
On-Site Educational Seminars
Worldwide Technical Sales Group
Centralized Product Applications Department
Research and Development Team
Technical Literature, O&M Manuals and Detailed CAD drawings all downloadable via our Website
MC-7200 MC-4500 MC-3500 SC-800 DC-780 SC-740 SC-310 SC-160LP

ENGINEERED SOLUTIONS
Modular Wetlands® Linear Operatons &
Maintenance Manual
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OOPPEERRAATTIIOONN && MMAAIINNTTEENNAANNCCEE MMAANNUUAALL

TTAABBLLEE OOFF CCOONNTTEENNTTSS
OOvveerrvviieeww ........................................................................................................................................................................ 3 SSaaffeettyy NNoottiiccee && PPeerrssoonnaall SSaaffeettyy EEqquuiippmmeenntt ................................................................................................................. 4 MMoodduullaarr WWeettllaannddss LLiinneeaarr CCoommppoonneennttss LLiisstt ................................................................................................................. 5 IInnssppeeccttiioonn SSuummmmaarryy && EEqquuiippmmeenntt LLiisstt ......................................................................................................................... 6 IInnssppeeccttiioonn && MMaaiinntteennaannccee NNootteess .................................................................................................................................. 7 IInnssppeeccttiioonn PPrroocceessss ......................................................................................................................................................... 7 MMaaiinntteennaannccee IInnddiiccaattoorrss ................................................................................................................................................. 9 MMaaiinntteennaannccee SSuummmmaarryy && EEqquuiippmmeenntt LLiisstt..................................................................................................................... 9 MMaaiinntteennaannccee IInnssttrruuccttiioonnss .............................................................................................................................................11 RReeppllaacciinngg BBiiooffiillttrraattiioonn MMeeddiiaa iiff RReeqquuiirreedd ....................................................................................................................14 RReeppllaacciinngg DDrraaiinn DDoowwnn FFiilltteerr MMeeddiiaa ((OOnnllyy oonn OOllddeerr CCaalliiffoorrnniiaa MMooddeellss)) .....................................................................16 NNootteess .............................................................................................................................................................................17 IInnssppeeccttiioonn RReeppoorrtt .........................................................................................................................................................18 CClleeaanniinngg && MMaaiinntteennaannccee RReeppoorrtt ..................................................................................................................................19 3 OOVVEERRVVIIEEWW
This operation and maintenance (O&M) manual is for the Modular Wetlands Linear Biofilter (MWL). Please read the instructions and equipment lists closely prior to starting. It is important to follow all necessary safety procedures associated with state and local regulations. Please contact Contech for more information on pre-authorized third-party service providers who can provide inspection and maintenance services in your area. For a list of service providers in your area, please visit www.conteches.com/maintenance.

PPLLAACCEEHHOOLLDDEERR FFOORR MMAARRKKEETTIINNGG PPHHOOTTOO

WWAARRNNIINNGG
Confined space entry may be required. Contractor to obtain all equipment and training to meet applicable local and OSHA regulations regarding confined space entry. It is the Contractor’s or entry personnel’s responsibility to always proceed safely.

4 SSAAFFEETTYY NNOOTTIICCEE && PPEERRSSOONNAALL SSAAFFEETTYY EEQQUUIIPPMMEENNTT Job site safety is a topic and a practice addressed comprehensively by others. The inclusions here are merely reminders to whole areas of Safety Practice that are the responsibility of the Owner(s), Manager(s), and Service Provider(s). OSHA and Canadian OSH, Federal, State/Provincial, and Local Jurisdiction Safety Standards apply on any given site or project.

The knowledge and applicability of those responsibilities is the Service Provider’s responsibility and outside the scope of Contech Engineered Solutions.

Safety Boots Gloves Hard Hat Eye Protection
Maintenance and Protection
of Traffic Plan

5 MMOODDUULLAARR WWEETTLLAANNDDSS LLIINNEEAARR CCOOMMPPOONNEENNTTSS LLIISSTT The MWL system comes in multiple sizes and configurations, including side by side or end to end layouts, both as open planters or underground systems. See shop drawings (plans) for project specific details.

The standard MWL system is comprised of the following components:

6 IINNSSPPEECCTTIIOONN SSUUMMMMAARRYY && EEQQUUIIPPMMEENNTT LLIISSTT Stormwater regulations require BMPs be inspected and maintained to ensure they are operating as designed to allow for effective pollutant removal and provide protection to receiving water bodies. It is recommended that inspections be performed multiple times during the first year to assess the site-specific loading conditions. The first year of inspections can be used to set inspection and maintenance intervals for subsequent years to ensure appropriate maintenance is provided.
 Inspect pre-treatment, biofiltration, and discharge chambers an average of once every six to twelve months. Varies based on site specific and local conditions.  Average inspection time is approximately 15 minutes. Always ensure appropriate safety protocol and procedures are followed.

The following is a list of equipment required to allow for simple and effective inspection of the MWL:

Modular Wetlands Linear
Inspection Form
Flashlight Tape Measure Access Cover Hook
Ratchet
& 7/16” Socket
(if required for older pre-filter
cartridges that have two
bolts holding the lids on)

7 IINNSSPPEECCTTIIOONN && MMAAIINNTTEENNAANNCCEE NNOOTTEESS

1. Following maintenance and/or inspection, it is recommended that the maintenance operator prepare a maintenance/inspection record. The record should include any maintenance activities performed, amount and description of debris collected, and condition of the system and its various filter mechanisms.

2. The owner should keep maintenance/inspection record(s) for a minimum of five years from the date of maintenance. These records should be made available to the governing municipality for inspection upon request at any time.

3. Transport all debris, trash, organics, and sediments to approved facility for disposal in accordance with local and state requirements.

4. Entry into chambers may require confined space training based on state and local regulations.

5. No fertilizer shall be used in the biofiltration chamber.

6. Irrigation should be provided as recommended by manufacturer and/or landscape architect. Amount of irrigation required is dependent on plant species. Some plants may not require irrigation after initial establishment.

IINNSSPPEECCTTIIOONN PPRROOCCEESSSS

1. Prepare the inspection form by writing in the necessary information including project name, location, date & time, unit number and other information (see inspection form).

2. Observe the inside of the system through the access covers. If minimal light is available and vision into the unit is impaired, utilize a flashlight to see inside the system and all chambers.

3. Look for any out of the ordinary obstructions in the inflow pipe, pre-treatment chamber, biofiltration chamber, discharge chamber or outflow pipe. Write down any observations on the inspection form.

4. Through observation and/or digital photographs, estimate the amount of trash, debris accumulated in the pre- treatment chamber. Utilizing a tape measure or measuring stick, estimate the amount of sediment in this chamber. Record this depth on the inspection form.

5. Through visual observation, inspect the condition of the pre-filter cartridges. Look for excessive build-up of sediment on the cartridges, any build-up on the tops of the cartridges, or clogging of the holes. Record this information on the inspection form. The pre-filter cartridges can be further inspected by removing the cartridge tops and assessing the color of the BioMediaGREEN filter cubes (requires entry into pre-treatment chamber - see notes previous notes regarding confined space entry). Record the color of the material. New material is a light green color. As the media becomes clogged, it will turn darker in color, eventually becoming dark brown or black. The closer to black the media is the higher percentage that the media is exhausted and in need of replacement.
8 6. The biofiltration chamber is generally maintenance-free due to the system’s advanced pre-treatment chamber.

For units which have open planters with vegetation, it is recommended that the vegetation be inspected. Look for any plants that are dead or showing signs of disease or other negative stressors. Record the general health of the plants on the inspection form and indicate through visual observation or digital photographs if trimming of the vegetation is required.

7. The discharge chamber houses the control riser (if applicable), drain down filter (only in California - older models), and is connected to the outflow pipe. It is important to check to ensure the orifice is in proper operating condition and free of any obstructions. It is also important to assess the condition of the drain down filter media which utilizes a block form of the BioMediaGREEN. Assess in the same manner as the cubes in the pre-filter cartridge as mentioned above.

8. Finalize the inspection report for analysis by the maintenance manager to determine if maintenance is required.

9 MMAAIINNTTEENNAANNCCEE IINNDDIICCAATTOORRSS
Based upon the observations made during inspection, maintenance of the system may be required based on the following indicators:
 Missing or damaged internal components or cartridges.  Obstructions in the system or its inlet and/or outlet pipes.  Excessive accumulation of floatables in the pre-treatment chamber in which the length and width of the chamber is fully impacted more than 18”.
 Excessive accumulation of sediment in the pre-treatment chamber of more than 6” in depth.  Excessive accumulation of sediment on the BioMediaGREEN media housed within the pretreatment cartridges.

When media is more than 85% clogged, replacement is required. The darker the BioMediaGREEN, the more clogged it is and in need of replacement.
 Excessive accumulation of sediment on the BioMediaGREEN media housed within the drain down filter (California only - older models).
 Overgrown vegetation.

MMAAIINNTTEENNAANNCCEE SSUUMMMMAARRYY && EEQQUUIIPPMMEENNTT LLIISSTT The time has come to maintain your MWL. All necessary pre-maintenance steps must be carried out before maintenance occurs. Once traffic control has been set up per local and state regulations and access covers have been safely opened, the maintenance process can begin. It should be noted that some maintenance activities require confined space entry.

All confined space requirements must be strictly followed before entry into the system. In addition, the following is recommended:
 Prepare the maintenance form by writing in the necessary information including project name, location, date & time, unit number and other info (see maintenance form).  Set up all appropriate safety and maintenance equipment.  Ensure traffic control is set up and properly positioned.  Prepared pre-checks (OSHA, safety, confined space entry) are performed. o A gas meter should be used to detect the presence of any hazardous gases prior to entering the system.

If hazardous gases are present, do not enter the vault. Following appropriate confined space procedures, take steps such as utilizing a venting system to address the hazard. Once it is determined to be safe, enter the system utilizing appropriate entry equipment such as a ladder and tripod with harness.
10 The following is a list of equipment required for maintenance of the MWL:

Modular Wetlands Linear
Maintenance Form
Flashlight Access Cover Hook Ratchet
& 7/16” Socket
(if required for older pre-filter
cartridges that have two
bolts holding the lids on)
Vacuum Assisted Truck with
Pressure Washer
Replacement
BioMediaGREEN
(If Required)
(order BioMediaGREEN from Contech’s Maintenance Team members at https://www.conteches.com/maintenance)

11 MMAAIINNTTEENNAANNCCEE IINNSSTTRRUUCCTTIIOONNSS

11.. AACCCCEESSSS CCOOVVEERR RREEMMOOVVAALL
Upon determining that the vault is safe for entry, remove all access cover(s) and position the vacuum truck
accordingly.

22.. PPRREESSSSUURREE WWAASSHH SSYYSSTTEEMM CCHHAAMMBBEERRSS With the pressure washer, spray down pollutants
accumulated on the walls and floors of the pre-
treatment and discharge chambers. Then wash any
accumulated sediment from the pre-filter cartridge(s).

33.. VVAACCUUUUMM SSYYSSTTEEMM CCHHAAMMBBEERRSS
Vacuum out pre-treatment and discharge chambers and
remove all accumulated pollutants including trash,
debris, and sediments. Be sure to vacuum the pre-
treatment floor until the pervious pavers are visible and clean. ((MMWWLL ssyysstteemmss oouuttssiiddee ooff CCaalliiffoorrnniiaa mmaayy oorr mmaayy nnoott hhaavvee ppeerrvviioouuss ppaavveerrss oonn tthhee fflloooorr iinn tthhee pprree-- ttrreeaattmmeenntt cchhaammbbeerr)) If pre-filter cartridges require media replacement, proceed toSStteepp 44. If not, replace the access cover(s) and proceed to SStteepp 77.

12 44.. PPRREE--FFIILLTTEERR CCAARRTTRRIIDDGGEE LLIIDD RREEMMOOVVAALL After successfully cleaning out the pre-treatment
chamber, enter the chamber and remove the lid(s) from
the pre-filter cartridge(s) by removing the two thumb
screws. (Older pre-filter cartridges have two bolts
holding the lids on that require a 7/16” socket to remove)

55.. VVAACCUUUUMM EEXXIISSTTIINNGG PPRREE--FFIILLTTEERR MMEEDDIIAA Utilize the vacuum truck hose or hose extension to
remove the filter media from each of the individual
media cages. Once filter media has been sucked out, use a pressure washer to spray down the inside of the
cartridge and its media cages. Remove cleaned media
cages and place to the side. Once removed, the vacuum
hose can be inserted into the cartridge to vacuum out
any remaining material near the bottom of the cartridge.

66.. PPRREE--FFIILLTTEERR MMEEDDIIAA RREEPPLLAACCEEMMEENNTT Reinstall media cages and fill with new media from the
manufacturer or outside supplier. Manufacturer will
provide specification of media and sources to purchase.

The easiest way to fill the media cages is to utilize a refilling tray that can also be sourced from the
manufacturer. Place the refilling tray on top of the
cartridge and fill with new bulk media shaking it down
into the cages. Using your hands, lightly compact the
media into each filter cage. Once the cages are full(each cartridge will hold five heaping 5gal buckets of bulk
media), remove the refilling tray and replace the
cartridge top, ensuring fasteners are properly tightened.

13 77.. MMAAIINNTTAAIINNIINNGG VVEEGGEETTAATTIIOONN
In general, the biofiltration chamber is maintenance-free with the exception of maintaining the vegetation. The
MWL utilizes vegetation similar to surrounding
landscape areas, therefore, trim vegetation to match
surrounding vegetation. If any plants have died, replace them with new ones.

88.. IINNSSPPEECCTT UUNNDDEERRDDRRAAIINN SSYYSSTTEEMM Each vertical under drain on the biofiltration chamber
has a removable threaded cap that can be taken off to
check for any blockages or root growth. Once removed,
a jetting attachment to the pressure washer can be used to clean out the under drain and orifice riser if needed.

99.. RREEPPLLAACCEE AACCCCEESSSS CCOOVVEERRSS
Once maintenance is complete, replace all access
cover(s)

14 RREEPPLLAACCIINNGG BBIIOOFFIILLTTRRAATTIIOONN MMEEDDIIAA IIFF RREEQQUUIIRREEDD As with all biofilter systems, at some point the biofiltration media will need to be replaced, either due to physical clogging or sorptive exhaustion (for dissolved pollutants) of the media ion exchange capacity (to remove dissolved metals and phosphorous). The general life of this media is 10 to 20 years based on site specific conditions and pollutant loading, so replacing the biofiltration media should not be a common occurrence. In the event that the biofiltration media requires replacement, contact one of Contech’s Maintenance Team members at https://www.conteches.com/maintenance to order new biofiltration media. The quantity of media needed can be determined by providing the model number and unit depth. Media will be provided in super sacks for easy installation.

Each sack will weigh between 1,000 and 2,000 lbs. Biofiltration media replacement can be done following the steps below:

11.. VVAACCUUUUMM EEXXIISSTTIINNGG BBIIOOFFIILLTTRRAATTIIOONN MMEEDDIIAA Remove the mulch and vegetation to access the
biofiltration media, and then position the vacuum truck accordingly. Utilize the vacuum truck to vacuum out all the media. Once all media is removed, use the pressure
washer to spray down all the netting and underdrain
systems on the inside of the media containment cage.

Vacuum out any remaining debris after spraying down
netting. Inspect the netting for any damage or holes. If the netting is damaged, it can be repaired or replaced
with guidance by the manufacturer.

22.. IINNSSTTAALLLLIINNGG NNEEWW BBIIOOFFIILLTTRRAATTIIOONN MMEEDDIIAA Ensure that the chamber is fully cleaned prior to
installation of new media into the media containment
cage(s). Media will be provided in super sacks for easy installation. A lifting apparatus (forklift, backhoe, boom truck, or other) is recommended to position the super
sack over the biofiltration chamber. Add media in lifts to ensure that the riser pipes remain vertical. Be sure to only fill the media cage(s) up to the same level as the old media.

15 33.. RREEPPLLAANNTT VVEEGGEETTAATTIIOONN
Once the media has been replaced, replant the
vegetation and cover biofiltration chamber with
approved mulch (if applicable). If the existing vegetation is not being reused, and new vegetation is being
planted, you will need to acquire new plant
establishment media that will be installed just below the mulch layer at each plant location. (see plan drawings for details). Contact one of Contech’s Maintenance Team
members at https://www.conteches.com/maintenance
to order new plant establishment media.

16 RREEPPLLAACCIINNGG DDRRAAIINN DDOOWWNN FFIILLTTEERR MMEEDDIIAA ((OONNLLYY OONN OOLLDDEERR CCAALLIIFFOORRNNIIAA MMOODDEELLSS)) NOTE: The drain down filter is only found on units installed in California prior to 2023 If during inspection it was determined that the drain down filter media requires replacement, contact one of Contech’s Maintenance Team members at https://www.conteches.com/maintenance to order new media.

11.. RREEMMOOVVEE EEXXIISSTTIINNGG DDRRAAIINN DDOOWWNN MMEEDDIIAA Pull knob back to unlock the locking mechanism and lift the drain down filter housing to remove the used
BioMediaGREEN filter block.

22.. IINNSSTTAALLLL NNEEWW DDRRAAIINN DDOOWWNN MMEEDDIIAA Ensure that the chamber and housing are fully cleaned
prior to installation of new media, and then insert the new BioMediaGREEN filter block. The media filter block
should fit snugly between the chamber walls and be
centered under the filter housing. Lower the housing
over the filter block and secure the locking mechanism.

17 NOTES
_______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ _______________________________________________________________________________________________________ 18 For Office Use Only
(city) (Zip Code) (Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( ) _
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Yes
Depth:

Yes No
Modular Wetland System Type (Curb, Grate or UG Vault): Size (22', 14' or etc.):

Other Inspection Items:

Storm Event in Last 72-hours? No YesType of Inspection Routine Follow Up Complaint Storm Office personnel to complete section to
the left.

Inspection Report
Modular Wetlands Linear
Is the filter insert (if applicable) at capacity and/or is there an accumulation of debris/trash on the shelf system? Does the cartridge filter media need replacement in pre-treatment chamber and/or discharge chamber? Any signs of improper functioning in the discharge chamber? Note issues in comments section.

Chamber:

Is the inlet/outlet pipe or drain down pipe damaged or otherwise not functioning properly? Structural Integrity:

Working Condition:

Is there evidence of illicit discharge or excessive oil, grease, or other automobile fluids entering and clogging the unit?
Is there standing water in inappropriate areas after a dry period? Damage to pre-treatment access cover (manhole cover/grate) or cannot be opened using normal lifting pressure?
Damage to discharge chamber access cover (manhole cover/grate) or cannot be opened using normal lifting pressure?
Does the MWS unit show signs of structural deterioration (cracks in the wall, damage to frame)? Project Name
Project Address
Inspection Checklist
CommentsNo
Does the depth of sediment/trash/debris suggest a blockage of the inflow pipe, bypass or cartridge filter? If yes, specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber.

Is there a septic or foul odor coming from inside the system? Is there an accumulation of sediment/trash/debris in the wetland media (if applicable)? Is it evident that the plants are alive and healthy (if applicable)? Please note Plant Information below.

Sediment / Silt / Clay
Trash / Bags / Bottles
Green Waste / Leaves / Foliage
Waste: Plant Information
No Cleaning Needed
Recommended Maintenance
Additional Notes:

Damage to Plants
Plant Replacement
Plant Trimming
Schedule Maintenance as Planned
Needs Immediate Maintenance

ENGINEERED SOLUTIONS
19 For Office Use Only
(city) (Zip Code) (Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( ) _
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Site
Map #
Comments:

Inlet and Outlet
Pipe Condition
Drain Down Pipe
Condition
Discharge Chamber
Condition
Drain Down Media
Condition
Plant Condition
Media Filter
Condition
Long:

MWS
Sedimentation
Basin
Total Debris
Accumulation
Condition of Media
25/50/75/100
(will be changed
@ 75%)
Operational Per
Manufactures'
Specifications
(If not, why?)
Lat: MWS
Catch Basins
GPS Coordinates
of Insert
Manufacturer /
Description / Sizing
Trash
Accumulation
Foliage
Accumulation
Sediment
Accumulation
Type of Inspection Routine Follow Up Complaint Storm Storm Event in Last 72-hours? No Yes Office personnel to complete section to
the left.

Project Address
Project Name
Cleaning and Maintenance Report
Modular Wetlands LinearENGINEERED SOLUTIONS

SUPPORT
DRAWINGS AND SPECIFICATIONS ARE AVAILABLE AT WWW.CONTECHES.COM © 2024 CONTECH ENGINEERED SOLUTIONS LLC, A QUIKRETE COMPANY 800-338-1122
WWW.CONTECHES.COM
ALL RIGHTS RESERVED. PRINTED IN THE USA.

CONTECH ENGINEERED SOLUTIONS LLC PROVIDES SITE SOLUTIONS FOR THE CIVIL ENGINEERING INDUSTRY. CONTECH’S PORTFOLIO INCLUDES BRIDGES, DRAINAGE, SANITARY SEWER, STORMWATER AND EARTH STABILIZATION PRODUCTS. FOR INFORMATION ON OTHER CONTECH DIVISION OFFERINGS, VISIT CONTECHES.COM OR CALL 800-338-1122.

ModWetLinear OM Manual 03/24
NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS

SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS

AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED

WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION.

ENGINEERED SOLUTIONS
City of San Marcos PDP SWQMP Template Date: March 15, 2016 PDP SWQMP Preparation Date: March 14, 2025
ATTACHMENT 4
Copy of Plan Sheets Showing Permanent Storm Water BMPs

This is the cover sheet for Attachment 4.

Use this checklist to ensure the required information has been included on the plans:

The plans must identify:

 Structural BMP(s) with ID numbers matching Form I-6 Summary of PDP Structural BMPs  The grading and drainage design shown on the plans must be consistent with the delineation of DMAs shown on the DMA exhibit
 Details and specifications for construction of structural BMP(s)  Signage indicating the location and boundary of structural BMP(s) as required by the [City Engineer]  How to access the structural BMP(s) to inspect and perform maintenance  Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds)
 Manufacturer and part number for proprietary parts of structural BMP(s) when applicable  Maintenance thresholds specific to the structural BMP(s), with a location-specific frame of reference (e.g., level of accumulated materials that triggers removal of the materials, to be identified based on viewing marks on silt posts or measured with a survey rod with respect to a fixed benchmark within the BMP)
 Recommended equipment to perform maintenance
 When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management  Include landscaping plan sheets showing vegetation requirements for vegetated structural BMP(s)  All BMPs must be fully dimensioned on the plans
 When proprietary BMPs are used, site-specific cross section with outflow, inflow, and model number shall be provided. Photocopies of general brochures are not acceptable.

STEVENS9665 Chesapeake Dr, Ste 200San Diego, CA 92123858.694.5660stevenscresto.comENGINEERSCRESTO

05.28.2025 CUBESMART SELF STORAGESAN MARCOS, CA
SHEET:CONDITIONAL USE PERMIT #:OWNER:ADDRESS:ARCHITECT, ENGINEERDESIGNER:CUP 24-0005CARMEL ENTERPRISE, LLCPHONE:(858) 342-24415550 CARMEL MOUNTAIN RD. SUITE 204 SAN DIEGO, CA 92130ARIEL VALLI - VALLI ARCHITECTURAL GROUPPHONE:(949) 813-4191ADDRESS:924-D N. ART VILLAGE WAY, IVINS UT 84738TYPE OF DEVELOPMENT: SELF STORAGELOCATION:337 E. CARMEL ST.SAN MARCOS CA 92069ZONE:OFFICE/COMMERCIAL (UNIVERSITY DISTRICT SPECIFIC PLAN)ASSESSOR'S PARCEL NUMBER(S):220-201-92SITE DATAAREA (sq.ft)COVERAGE %LOT:BUILDING:PARKING:LOADING/DRIVEWAYS:117,98941,0002,08847,143100%34.75%1.77%39.95%LANDSCAPING:27,75823.53%PARKINGGARAGE:COVERED:OPEN:007LOADINGHANDICAPTOTAL4112

DRIVEWAY (SIZEAND SLOPE)ONE WAYTWO WAYSLOPE
SETBACKSFRONT:LEFT SIDE:RIGHT SIDE:REAR:89'-2"49'-0" BLDG. A / 6'-4" BLDG. B69'-1" BLDG. A / 58'-9" BLDG. B0 TITLE SHEETC1

STEVENS9665 Chesapeake Dr, Ste 200San Diego, CA 92123858.694.5660stevenscresto.comENGINEERSCRESTO

05.28.2025 CUBESMART SELF STORAGESAN MARCOS, CA
SHEET:CONDITIONAL USE PERMIT #:OWNER:ADDRESS:ARCHITECT, ENGINEERDESIGNER:CUP 24-0005CARMEL ENTERPRISE, LLCPHONE:(858) 342-24415550 CARMEL MOUNTAIN RD. SUITE 204 SAN DIEGO, CA 92130ARIEL VALLI - VALLI ARCHITECTURAL GROUPPHONE:(949) 813-4191ADDRESS:924-D N. ART VILLAGE WAY, IVINS UT 84738TYPE OF DEVELOPMENT: SELF STORAGELOCATION:337 E. CARMEL ST.SAN MARCOS CA 92069ZONE:OFFICE/COMMERCIAL (UNIVERSITY DISTRICT SPECIFIC PLAN)ASSESSOR'S PARCEL NUMBER(S):220-201-92SITE DATAAREA (sq.ft)COVERAGE %LOT:BUILDING:PARKING:LOADING/DRIVEWAYS:117,98941,0002,08847,143100%34.75%1.77%39.95%LANDSCAPING:27,75823.53%PARKINGGARAGE:COVERED:OPEN:007LOADINGHANDICAPTOTAL4112

DRIVEWAY (SIZEAND SLOPE)ONE WAYTWO WAYSLOPE
SETBACKSFRONT:LEFT SIDE:RIGHT SIDE:REAR:89'-2"49'-0" BLDG. A / 6'-4" BLDG. B69'-1" BLDG. A / 58'-9" BLDG. B0 EXISTING CONDITIONSC2

STEVENS9665 Chesapeake Dr, Ste 200San Diego, CA 92123858.694.5660stevenscresto.comENGINEERSCRESTO

05.28.2025 CUBESMART SELF STORAGESAN MARCOS, CA
SHEET:CONDITIONAL USE PERMIT #:OWNER:ADDRESS:ARCHITECT, ENGINEERDESIGNER:CUP 24-0005CARMEL ENTERPRISE, LLCPHONE:(858) 342-24415550 CARMEL MOUNTAIN RD. SUITE 204 SAN DIEGO, CA 92130ARIEL VALLI - VALLI ARCHITECTURAL GROUPPHONE:(949) 813-4191ADDRESS:924-D N. ART VILLAGE WAY, IVINS UT 84738TYPE OF DEVELOPMENT: SELF STORAGELOCATION:337 E. CARMEL ST.SAN MARCOS CA 92069ZONE:OFFICE/COMMERCIAL (UNIVERSITY DISTRICT SPECIFIC PLAN)ASSESSOR'S PARCEL NUMBER(S):220-201-92SITE DATAAREA (sq.ft)COVERAGE %LOT:BUILDING:PARKING:LOADING/DRIVEWAYS:117,98941,0002,08847,143100%34.75%1.77%39.95%LANDSCAPING:27,75823.53%PARKINGGARAGE:COVERED:OPEN:007LOADINGHANDICAPTOTAL4112

DRIVEWAY (SIZEAND SLOPE)ONE WAYTWO WAYSLOPE
SETBACKSFRONT:LEFT SIDE:RIGHT SIDE:REAR:89'-2"49'-0" BLDG. A / 6'-4" BLDG. B69'-1" BLDG. A / 58'-9" BLDG. B0 CONCEPT GRADING & UTILITY PLANC3

STEVENS9665 Chesapeake Dr, Ste 200San Diego, CA 92123858.694.5660stevenscresto.comENGINEERSCRESTO

05.28.2025 CUBESMART SELF STORAGESAN MARCOS, CA
SHEET:CONDITIONAL USE PERMIT #:OWNER:ADDRESS:ARCHITECT, ENGINEERDESIGNER:CUP 24-0005CARMEL ENTERPRISE, LLCPHONE:(858) 342-24415550 CARMEL MOUNTAIN RD. SUITE 204 SAN DIEGO, CA 92130ARIEL VALLI - VALLI ARCHITECTURAL GROUPPHONE:(949) 813-4191ADDRESS:924-D N. ART VILLAGE WAY, IVINS UT 84738TYPE OF DEVELOPMENT: SELF STORAGELOCATION:337 E. CARMEL ST.SAN MARCOS CA 92069ZONE:OFFICE/COMMERCIAL (UNIVERSITY DISTRICT SPECIFIC PLAN)ASSESSOR'S PARCEL NUMBER(S):220-201-92SITE DATAAREA (sq.ft)COVERAGE %LOT:BUILDING:PARKING:LOADING/DRIVEWAYS:117,98941,0002,08847,143100%34.75%1.77%39.95%LANDSCAPING:27,75823.53%PARKINGGARAGE:COVERED:OPEN:007LOADINGHANDICAPTOTAL4112

DRIVEWAY (SIZEAND SLOPE)ONE WAYTWO WAYSLOPE
SETBACKSFRONT:LEFT SIDE:RIGHT SIDE:REAR:89'-2"49'-0" BLDG. A / 6'-4" BLDG. B69'-1" BLDG. A / 58'-9" BLDG. B0 CONCEPT STORM WATER BMP PLANC4

STEVENS9665 Chesapeake Dr, Ste 200San Diego, CA 92123858.694.5660stevenscresto.comENGINEERSCRESTO

05.28.2025 CUBESMART SELF STORAGESAN MARCOS, CA
SHEET:CONDITIONAL USE PERMIT #:OWNER:ADDRESS:ARCHITECT, ENGINEERDESIGNER:CUP 24-0005CARMEL ENTERPRISE, LLCPHONE:(858) 342-24415550 CARMEL MOUNTAIN RD. SUITE 204 SAN DIEGO, CA 92130ARIEL VALLI - VALLI ARCHITECTURAL GROUPPHONE:(949) 813-4191ADDRESS:924-D N. ART VILLAGE WAY, IVINS UT 84738TYPE OF DEVELOPMENT: SELF STORAGELOCATION:337 E. CARMEL ST.SAN MARCOS CA 92069ZONE:OFFICE/COMMERCIAL (UNIVERSITY DISTRICT SPECIFIC PLAN)ASSESSOR'S PARCEL NUMBER(S):220-201-92SITE DATAAREA (sq.ft)COVERAGE %LOT:BUILDING:PARKING:LOADING/DRIVEWAYS:117,98941,0002,08847,143100%34.75%1.77%39.95%LANDSCAPING:27,75823.53%PARKINGGARAGE:COVERED:OPEN:007LOADINGHANDICAPTOTAL4112

DRIVEWAY (SIZEAND SLOPE)ONE WAYTWO WAYSLOPE
SETBACKSFRONT:LEFT SIDE:RIGHT SIDE:REAR:89'-2"49'-0" BLDG. A / 6'-4" BLDG. B69'-1" BLDG. A / 58'-9" BLDG. B0 CONCEPT FIRE TRUCK ACCESS PLANC5