New Development and Redevelopment

Natural landscapes filter & recycle stormwater. Impervious development causes high volumes of stormwater to “run off” into urban storm drains & creeks (Adapted from US EPA)

Urban development traditionally involves replacing natural landscapes with impervious areas, such as roofs, pavements, streets, and storm drain systems, causing greater amounts of polluted stormwater runoff to flow directly into creeks.

The impact of urban development on waterways can be reduced by using Low Impact Development (LID) techniques. LID techniques reduce runoff and mimic a site’s natural (predevelopment) hydrology by minimizing disturbed areas and impervious surfaces, and retaining and treating stormwater runoff using infiltration, evapotranspiration, rainwater harvesting and use, or biotreatment.

Private and public new and redevelopment projects that create or replace amounts of impervious surface that exceed certain thresholds are required to include appropriate site design, pollutant source control, treatment measures, and where appropriate, hydromodification management measures that improve, protect and treat urban runoff.  Local municipalities have developed Green Stormwater Infrastructure (GSI) Plans for incorporating LID features into public lands, such as streets, buildings, parking lots, and parks.

Key Guidance Documents

Site Design Measures

Disconnected downspouts allow roof runoff to flow into landscaping (Photo by Program staff) Site design measures are site planning techniques that can help reduce the impacts of increased runoff and pollution from land development on water quality.  Examples include preserving existing vegetation, reducing impervious surfaces, directing runoff to vegetated areas, using pervious pavement, and directing...

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Pollutant Source Control Measures

Covered dumpster area (Photo by Program staff) Vehicle wash area with drain connected to sanitary sewer (Photo by Program staff) Source controls prevent potential pollutant sources from coming in contact with rainfall and runoff. Examples include: roofed trash enclosures, covered outdoor materials handling and storage areas, storm drain labeling, and sanitary sewer drains for vehicle...

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Treatment Control Measures

Stormwater treatment measures are systems designed to remove pollutants from stormwater before it reaches the storm drain system.  Examples of allowable treatment measures for most projects include: bioretention areas, flow-through planters, infiltration facilities (e.g., trenches, pervious pavements, or subsurface systems), and rainwater harvesting systems.  Vault-based treatment systems are only allowed at certain high-density projects that...

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Hydromodification Controls

Eroded creek filled with sediment (Photo by Program staff) When land is covered with buildings and pavement, runoff enters creeks at higher rates and volumes, resulting in channel erosion, flooding and habitat loss.  These changes in runoff characteristics are known as hydromodification.  Hydromodification management measures are detention and/or infiltration facilities that are constructed with special...

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New Development and Redevelopment Resources and Fact Sheets

SCVURPPP Qualified Consultant List SCVURPPP C.3. Stormwater Handbook DateTitleCategoriesTags1/24/2024Sizing for Flow-Based Treatment MeasuresOther DocumentsNew Development (C.3.)1/24/2024Sizing for Flow and Volume-Based Treatment Measures (Combination Flow and Volume Approach)Other DocumentsNew Development (C.3.)1/24/2024Sizing for Volume-Based Treatment Measures Based on the Adapted CASQA Stormwater BMP Handbook ApproachOther DocumentsNew Development (C.3.)12/21/2023Special Projects WorksheetOther DocumentsNew Development (C.3.)6/30/2023Green Stormwater Infrastructure Vegetation GuideOther...

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Operation & Maintenance

Maintenance is essential for assuring that stormwater treatment and hydromodification management measures continue to function effectively and do not cause flooding, provide habitat for mosquitoes, or otherwise become a nuisance.  To ensure that property owners are maintaining treatment measures, Santa Clara Valley municipal agencies have inspection and reporting programs in-place. Property owners are required to...

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New Development & Redevelopment Documents

1/24/2024Sizing for Flow-Based Treatment MeasuresOther Documents
1/24/2024Sizing for Flow and Volume-Based Treatment Measures (Combination Flow and Volume Approach)Other Documents
1/24/2024Sizing for Volume-Based Treatment Measures Based on the Adapted CASQA Stormwater BMP Handbook ApproachOther Documents
12/21/2023Special Projects WorksheetOther Documents
6/30/2023Green Stormwater Infrastructure Vegetation GuideOther Documents, Uncategorized, ,
4/25/2023Annual C.3 Workshop – Addressing Stormwater Requirements in Development Project Plan Review – April 25, 2023Workshops
4/19/2023Provision C.3 Data FormForms
4/19/2023New Stormwater Control Requirements for Large Single-Family Home Development Fact SheetFact Sheets
2/28/2023Annual C.3 Workshop – Part 1: Green Stormwater Infrastructure in the Public Right-of-Way – Implementing New Requirements – February 28, 2023Workshops
1/12/2023Stormwater Quality Control Requirements – Information for Developers, Builders and Project Applicants, Effective July 1, 2023Fact Sheets
1/12/2023Update on Stormwater Treatment Requirements for New Development and Redevelopment Projects, Effective July 1, 2023Fact Sheets
12/20/2022SCVURPPP List of Qualified ConsultantsOther Documents
6/9/2022Annual C3 Workshop – June 9, 2022Workshops
7/16/2021New and Redevelopment Projects Litter Reduction Fact SheetFact Sheets, ,
7/1/2021Biotreatment Soil Mix Verification Checklist (PDF Form)Checklists
7/1/2021Biotreatment Soil Media and Mulch GuidanceGuidance Documents
6/10/2021Annual C.3 Workshop – Moving Forward with Green Stormwater Infrastructure ImplementationWorkshops
10/29/2019Annual C.3 Workshop – Installation and O&M Inspections of Stormwater Treatment MeasuresWorkshops
9/24/2019Drainage Management Area Summary TableForms
9/1/2019SCVURPPP Green Stormwater Infrastructure HandbookGuidance Documents,
12/4/2018SWRP Public Meetings August 28 & September 6, 2018Meeting Agendas, Presentations
11/29/2018Workshop Materials – Stormwater Resource and Green Stormwater Infrastructure Planning: Opportunities for Multi-Benefit Projects in Santa Clara Valley – 11/29/18Workshops,
11/29/2018Stormwater Resource and Green Stormwater Infrastructure Planning: Opportunities for Multi-Benefit ProjectsWorkshops
8/29/2018GSI Handbook Workshop #2 – April 24, 2018Workshops,
8/29/2018GSI Handbook Workshop #1 – April 10, 2018Workshops,
6/7/2017Stormwater Control Measure Requirements for Development Projects – June 7 and 13, 2017Workshops
4/19/2017Green Infrastructure Design and Implementation Workshop – April 19, 2017Workshops,
1/23/2017Stormwater Controls (C.3.h) Inspection Workshop – January 23 and 27, 2017Workshops
9/1/2016Integrating Green Infrastructure into Public Streets, Roads, Buildings, and Parking Lots (for elected officials)Fact Sheets
9/1/2016Greening Our Streets, Buildings, and Parking Lots (for general public)Fact Sheets
6/20/2016C.3 Stormwater Handbook (June 2016)Reports
6/9/2016Annual C.3 Workshop June 9, 2016Workshops
6/1/2016Biotreatment Soil Mix Supplier Certification StatementCertification Statements
4/25/2016Green Infrastructure Workshop – Series 1 – April 25, 2016Workshops
4/18/2016BASMAA Regional Biotreatment Soil Specification (2016)Guidance Documents
6/16/2015Annual C.3. Stormwater Workshop: “Low Impact Development and Green Infrastructure – What Will the Future Bring?” – June 16, 2015Workshops
5/6/2015C.3.h O&M Stormwater Inspection Compliance Workshop: Implementing the requirements in MRP Provision C.3.h – May 6, 2015Workshops
6/4/2014Annual C.3. Stormwater Workshop: Current Trends in Low Impact Development and Green Street Implementation – June 4, 2014Workshops
4/8/2014Biotreatment Soil Mix Research and Verification Guidance DevelopmentGuidance Documents
4/8/2014Guidance on Biotreatment Soil Mix Review and Approval OptionsGuidance Documents
12/16/2013Stormwater Treatment Facility Inspection Workshop – December 16, 2013Workshops
11/1/2012Rain Garden Fact SheetFact Sheets
8/1/2012Landscape Dispersion Fact SheetFact Sheets
8/1/2012Rain Barrel Fact SheetFact Sheets
8/1/2012Pervious Paving Fact SheetFact Sheets
12/18/2010Biotreatment Soil Mix Research and Verification Guidance DevelopmentGuidance Documents
4/9/2009HMP Cost Estimating GuidanceGuidance Documents
10/12/2006Impervious Surface Area Thresholds for Control of Hyrdomodification: an Evaluation Using Data from The Santa Clara BasinReports
6/6/2006Restricted contentFact Sheets,
4/21/2005Hydromodification Management Plan Final ReportReports
4/21/2005Hydromodification Management PlanGuidance Documents