Connecticut Stormwater Quality Manual

--Updated Guidance Now Published--

The Department of Energy and Environmental Protection and the Connecticut Council on Soil and Water Conservation have collaborated to prepare the revised for the Connecticut Guidelines for Soil Erosion and Sediment Control and the Connecticut Stormwater Quality Manual (below). The effective date for these guidance documents is March 30, 2024. The full adoption of these documents will be phased, please see the details provided in Chapter 1. During the phased in adoption of the revised manual the 2004 version will also remain available below. As of September 30, 2024 the 2004 version will no longer be hosted online.

The revisions to these documents include:

 

• Reformatting the Stormwater Quality Manual to focus on function
• Updating the 90th percentile water quality storm and design storms with more recent data.
• Including the Environmental Protection Agency’s performance curves to aide in evaluating the appropriate selection and sizing of best management practices for site-specific conditions.
• Incorporating updated Low Impact Development guidance into the body of the document to be consistent with permit requirements
• Adding workflow processes and checklists to streamline site design to meet a variety of stormwater quality programs and promote site design to preserve on site assets.
• Updating technical design details.
• Updates to provide better consistency between the two guidance documents.

Updated Stormwater Quality Manual

The Connecticut Stormwater Quality Manual provides guidance on the measures necessary to protect the waters of the State of Connecticut from the adverse impacts of post-construction stormwater runoff. This manual focuses on site planning, source control, and stormwater treatment practices and is intended for use as a planning tool and design guidance document by the regulated and regulatory communities involved in stormwater quality management.

View the Full Connecticut Stormwater Quality Manual

Or choose one or more of the specific sections to download separately:

• Title Page, Acknowledgements and Table of Contents
• Background Chapters 1-3 (Introduction, Stormwater Impacts, and Preventing and Mitigating Stormwater Impacts)
• Design Chapters (Set 1) 4-7 (Stormwater Management Standards and Criteria, Low Impact Development Site Planning and Design Strategies, Source Control Practices and Pollution Prevention, and Overview of Structural Stormwater Best Management Practices)
• Design Chapters (Set 2) 8-11 (Selection Considerations for Stormwater BMPS, Stormwater Retrofits, General Guidance for Stormwater Infiltration Systems and Proprietary Stormwater BMPs)
• Design Chapters (Set 3) 12 (Stormwater Management Plan) and 13 (Structural Stormwater BMP Guidance)
• Appendices

 

 2004 Connecticut Stormwater Quality Manual

Errata Sheet for the Connecticut Stormwater Quality Manual The manual can be viewed in two ways: The complete manual or individual chapters.

Stormwater Quality Worksheet (Word) (PDF) This worksheet is to be used in conjunction with the Connecticut Stormwater Quality Manual for any new land development. It is designed to help the regulated community and regulatory agencies work through the recommendations provided in the 2004 Connecticut Stormwater Quality Manual. It is not currently required to be submitted with any permit applications submitted to the Connecticut Department of Energy and Environmental Protection (DEEP).

Stormwater Quality Manual - View Complete Stormwater Manual 

Stormwater Quality Manual - View By Chapter

Table of Contents (PDF)

• Chapter 1 - Introduction (PDF)

• Chapter 2 - Why Stormwater Matters:  The Impacts of Urbanization (PDF)

• Chapter 3 - Preventing and Mitigating Stormwater Impacts (PDF)

• Chapter 4 - Site Planning and Design (PDF)

• Chapter 5 - Source Control Practices and Pollution Prevention (PDF)

• Chapter 6 - Introduction to Stormwater Treatment Practices (PDF)

• Chapter 7 - Hydrologic Sizing Criteria for Stormwater Treatment Practices (PDF)

• Chapter 8 - Selection Criteria for Stormwater Treatment Practices (PDF)

• Chapter 9 - Developing a Site Stormwater Management Plan (PDF)

• Chapter 10 - Stormwater Retrofits (PDF)

• Chapter 11 - Stormwater Treatment Practice Design Guidance Introduction (PDF)

  • Primary (P) Treatment Practices

    • Stormwater Ponds (PDF)

    • Stormwater Wetlands (PDF)

    • Infiltration Practices (PDF)

    • Filtering Practices (PDF)

    • Water Quality Swales (PDF)

  • Secondary (S) Treatment Practices - Conventional Practices

    • Dry Detention Ponds (PDF)

    • Underground Detention Facilities (PDF)

    • Deep Sump Catch Basins (PDF)

    • Oil/Particle Separators (PD)

    • Dry Wells (PDF)

    • Permeable Pavement (PDF)

    • Vegetated Filter Strips/Level Spreaders (PDF)

    • Grass Drainage Channels (PDF)

  • Secondary (S) Treatment Practices - Innovative/Emerging Technologies

    • Catch Basin Inserts (PDF)

    • Hydrodynamic Separators (PDF)

    • Media Filters (PDF)

    • Underground Infiltration Systems (PDF)

    • Alum Injection (PDF)

• Appendix A - Plant List (PDF)

• Appendix B - Water Quality Flow and Flow Diversion Guidance (PDF)

• Appendix C - Model Ordinances (PDF)

• Appendix D - Site Stormwater Management Plan Checklist (PDF)

• Appendix E - Maintenance Inspection Checklist (PDF)

• Appendix F - Glossary (PDF)

• Low Impact Development (LID) Appendices and Incorporation of LID Principles

Stormwater Index

Content Last Updated July 3, 2024