Stormwater Retrofits

Stormwater retrofitting is providing stormwater treatment on existing development that is currently untreated by any BMP or is inadequately treated by an existing BMP. Here you will find multiple resources that define stormwater retrofits, explain the process behind finding potential retrofit opportunities as well as the challenges that stormwater retrofitting may pose.

U-1 Urban Stormwater Retrofits Fact Sheet

A 'fact sheet' on using Urban Stormwater Retrofits as a BMP in the Chesapeake Bay Watershed.

Version june 2015 | Size (681 KB) | File type (.pdf) | Download

Urban Subwatershed Restoration Manual 3: Urban Stormwater Retrofit Practices

From the Urban Subwatershed Restoration Manual (USRM) Series, Manual 3

Version 1.0 | Size (12 MB) | File type (.pdf) | Download

Urban Subwatershed Restoration Manual 3: Urban Stormwater Retrofit Practices Appendices

From the Urban Subwatershed Restoration Manual (USRM) Series, Manual 3

Size (7 MB) | File type (.pdf) | Download

Retrofitting Tools and Resources

Retrofit Reconnaissance Investigation (RRI) Form, Modified

A modified version of the Retrofit Reconnaissance Investigation (RRI) Form.

Size (80 KB) | File type (.doc) | Download

Retrofit Method Spreadsheet

Stormwater retrofit methods calculations. Enter retrofit area, runoff coefficient, impervious area, etc to determine runoff reduction and cost for various stormwater retrofit installations.

Version 2.0 | Size (166 KB) | File type (.xlsx) | Download

Retrofit Sizing Worksheet

Worksheet to aid in appropriate sizing for retrofits.

Size (192 KB) | File type (.xlsx) | Download

Completed Example of a Retrofit Reconnaissance Investigation (RRI) Form

A completed Retrofit Reconnaissance Investigation (RRI) Form for Arlington County to be used as an example.

Size (667 KB) | File type (.pdf) | Download

Retrofit Reconnaissance Investigation (RRI) Form, Modified for Volunteers

The Retrofit Reconnaissance Investigation (RRI) Form, modified for use by volunteers.

Size (66 KB) | File type (.doc) | Download

Accounting Guidance for Meeting the Bay TMDL

Final CBP Approved Expert Panel Report on Stormwater Retrofits (Short Version)

Final CBP Approved Expert Panel Report on Stormwater Retrofits Short Version. To see the long version go here.

Version short, january 20, 2015 | Size (1 MB) | File type (.pdf) | Download

Frequently Asked Questions for Stormwater Performance Standards and Retrofit Expert Panel Reports

This is a companion document to the expert panel reports on on the retrofit and performance standards expert panel reports that clarifies how the practices will be credited, identifies who the state stormwater contacts are, outlines the reporting and tracking requirements for NEIN and Scenario Builder, corrects errata, and provides any state-specific decisions/interpretations on how the reports are to be properly used.

Version may 25, 2015 | Size (521 KB) | File type (.pdf) | Download

[Webcast] Accounting for Urban Stormwater Retrofits and Urban Filter Strips

Residential Retrofit Resources

[Webcast] MS4 Implementers and the Bay TMDL: Homeowner Stormwater Controls

[Webcast] Creating or Enhancing Your Local Residential BMP Program

RainScapes Program Overview

January 2011 Overview of The Montgomery County RainScapes Program

Size (578 KB) | File type (.pdf) | Download

Training Resources

Fairfax Retrofit Workshop Powerpoints

Presentations from our 2-day workshop on Stormwater Retrofitting held on April 29-30, 2013 in Fairfax, VA. This free workshop was aimed at practitioners with at least a basic understanding of stormwater management design and with an interest in learning more about the nuts and bolts of stormwater retrofitting. The focus of the training was on how to locate and prioritize retrofit opportunities in developed areas, through field investigations and concept drawings and covered retrofitting streets, existing stormwater basins, public lands, and other topics.

Size (18 MB) | File type (.pdf) | Download

Retrofit This: A Guide to Retrofitting the World?

A combined effort between CSN and the Center for Watershed Protection with special guests from Montgomery County, MD, Arlington County, VA, and Seattle Public Utilities. This webcast introduces a retrofitting practice hierarchy and describes how to find, prioritize, and build the most effective retrofits. The webcast also discusses how much land area in a watershed can feasibly be retrofitted and at what cost based on dozens of retrofit studies conducted in urban, suburban, and rural watersheds.

Size (84 MB) | File type (.ppsx) | Download

Stormwater Retrofits to Maximize Nutrient Reduction

Stormwater Retrofitting Demystified

Compiled presentations from the June 13, 2012 workshop on Stormwater Retrofits. This workshop was hosted by MD DNR.  

Version june 2012 | Size (18 MB) | File type (.pdf) | Download

Other Resources

Technical Bulletin No 7: Stormwater Pollution Benchmarking Tool

Stormwater Pollution Benchmarking Tool for Existing Industrial, Federal and Municipal Facilities in the Chesapeake Bay Watershed

Version 1.0 | Size (3 MB) | File type (.pdf) | Download

Understanding Watershed Behavior

Article 126 from Watershed Protection Techniques. 3(3): 671 - 679

Size (47 KB) | File type (.pdf) | Download

On Watershed Education

Article 127 from Watershed Protection Techniques. 3(3): 680 - 686

Size (476 KB) | File type (.pdf) | Download

Download All Files Above

Download all the files in Stormwater Retrofits section as a compressed .zip file.

Size (13.12 MB) | File type (.zip) | Download