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.
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 hydromodification management measures
Key Guidance Documents
New Development & Redevelopment Documents
Date Title Categories Tags 4/7/2026 SCVURPPP Annual C.3 Workshop – Implementing Provision C.3 Requirements, April 8, 2026 Workshops New Development (C.3.) 4/1/2026 MRP Provision C.3 Compliance Webinar – April 1, 2026 Workshops New Development (C.3.) 8/1/2025 SCVURPPP Green Stormwater Infrastructure Handbook Guidance Documents GSI , New Development (C.3.) 5/1/2025 Biotreatment Soil Media and Mulch Guidance Guidance Documents New Development (C.3.) 4/28/2025 Annual C3 Workshop Low Impact Development and Green Stormwater Infrastructure: Design and Maintenance Tuesday – April 29, 2025 Workshops New Development (C.3.) 4/17/2025 SCVURPPP Site Design Manual – Revised February 2007 Guidance Documents New Development (C.3.) 11/12/2024 SCVURPPP List of Qualified Consultants – November 12, 2024 Other Documents New Development (C.3.) 10/28/2024 C.3 Stormwater Handbook (October 2024) Guidance Documents New Development (C.3.) 9/19/2024 Provision C.3 Data Form 2024 Forms New Development (C.3.) 1/24/2024 Sizing for Flow-Based Treatment Measures Other Documents New Development (C.3.) 1/24/2024 Sizing for Flow and Volume-Based Treatment Measures (Combination Flow and Volume Approach) Other Documents New Development (C.3.) 1/24/2024 Sizing for Volume-Based Treatment Measures Based on the Adapted CASQA Stormwater BMP Handbook Approach Other Documents New Development (C.3.) 12/21/2023 Special Projects Worksheet Other Documents New Development (C.3.) 6/30/2023 Green Stormwater Infrastructure Vegetation Guide Other Documents , Uncategorized Bioretention , GSI , New Development (C.3.) 4/25/2023 Annual C.3 Workshop – Addressing Stormwater Requirements in Development Project Plan Review – April 25, 2023 Workshops New Development (C.3.) 4/19/2023 New Stormwater Control Requirements for Large Single-Family Home Development Fact Sheet Fact Sheets New Development (C.3.) 2/28/2023 Annual C.3 Workshop – Part 1: Green Stormwater Infrastructure in the Public Right-of-Way – Implementing New Requirements – February 28, 2023 Workshops New Development (C.3.) 1/12/2023 Stormwater Quality Control Requirements – Information for Developers, Builders and Project Applicants, Effective July 1, 2023 Fact Sheets New Development (C.3.) 1/12/2023 Update on Stormwater Treatment Requirements for New Development and Redevelopment Projects, Effective July 1, 2023 Fact Sheets New Development (C.3.) 6/9/2022 Annual C3 Workshop – June 9, 2022 Workshops New Development (C.3.) 7/1/2021 Biotreatment Soil Mix Verification Checklist (PDF Form) Checklists New Development (C.3.) 6/10/2021 Annual C.3 Workshop – Moving Forward with Green Stormwater Infrastructure Implementation, June 10, 2021 Workshops New Development (C.3.) 10/29/2019 Annual C.3 Workshop – Installation and O&M Inspections of Stormwater Treatment Measures, October 29, 2019 Workshops New Development (C.3.) 9/24/2019 Drainage Management Area Summary Table Forms New Development (C.3.) 12/4/2018 SWRP Public Meetings August 28 & September 6, 2018 Meeting Agendas , Presentations New Development (C.3.) 11/29/2018 Workshop Materials – Stormwater Resource and Green Stormwater Infrastructure Planning: Opportunities for Multi-Benefit Projects in Santa Clara Valley – 11/29/18 Workshops GSI , New Development (C.3.) 11/29/2018 Stormwater Resource and Green Stormwater Infrastructure Planning: Opportunities for Multi-Benefit Projects, November 29, 2018 Workshops New Development (C.3.) 8/29/2018 GSI Handbook Workshop #2 – April 24, 2018 Workshops GSI , New Development (C.3.) 8/29/2018 GSI Handbook Workshop #1 – April 10, 2018 Workshops GSI , New Development (C.3.) 6/7/2017 Stormwater Control Measure Requirements for Development Projects – June 7 and 13, 2017 Workshops New Development (C.3.) 4/19/2017 Green Infrastructure Design and Implementation Workshop – April 19, 2017 Workshops GSI , New Development (C.3.) 1/23/2017 Stormwater Controls (C.3.h) Inspection Workshop – January 23 and 27, 2017 Workshops New Development (C.3.) 9/1/2016 Integrating Green Infrastructure into Public Streets, Roads, Buildings, and Parking Lots (for elected officials) Fact Sheets New Development (C.3.) 9/1/2016 Greening Our Streets, Buildings, and Parking Lots (for general public) Fact Sheets New Development (C.3.) 6/9/2016 Annual C.3 Workshop June 9, 2016 Workshops New Development (C.3.) 6/1/2016 Biotreatment Soil Mix Supplier Certification Statement Certification Statements New Development (C.3.) 4/25/2016 Green Infrastructure Workshop – Series 1 – April 25, 2016 Workshops New Development (C.3.) 4/18/2016 BASMAA Regional Biotreatment Soil Specification (2016) Guidance Documents New Development (C.3.) 6/16/2015 Annual C.3. Stormwater Workshop: “Low Impact Development and Green Infrastructure – What Will the Future Bring?” – June 16, 2015 Workshops New Development (C.3.) 5/6/2015 C.3.h O&M Stormwater Inspection Compliance Workshop: Implementing the requirements in MRP Provision C.3.h – May 6, 2015 Workshops New Development (C.3.) 6/4/2014 Annual C.3. Stormwater Workshop: Current Trends in Low Impact Development and Green Street Implementation – June 4, 2014 Workshops New Development (C.3.) 4/8/2014 Biotreatment Soil Mix Research and Verification Guidance Development Guidance Documents New Development (C.3.) 10/12/2006 Impervious Surface Area Thresholds for Control of Hyrdomodification: an Evaluation Using Data from The Santa Clara Basin Reports New Development (C.3.) 6/6/2006 Restricted content Fact Sheets Archive , New Development (C.3.) 4/21/2005 Hydromodification Management Plan Final Report Reports New Development (C.3.) 4/21/2005 Hydromodification Management Plan Guidance Documents New Development (C.3.)
