Stormwater Management

Our stormwater services are based on scientific research, practical field experience, publications that define and illustrate our approach, and partnerships with communities around the country to provide sound protection strategies and improve the effectiveness of their watershed and stormwater programs.

Arguably the nation's leading stormwater clearinghouse, the Center is known for distilling stormwater research, developing state and regional stormwater design manuals, and helping communities build post-construction stormwater programs. The Center has worked directly with numerous local and state agencies to provide effective stormwater solutions in geographically diverse settings around the country.  Stormwater services we provide commonly include:

• Developing stormwater design manuals—you can see our work in the MN, NY, VT, MD, Washington DC, and GA design manuals.
• Designing individual stormwater practices—innovative on-site and off-site designs incorporating landscape, maintenance, and sizing criteria adapted to your watershed
• Evaluating local stormwater ordinances—we have been developing a new model ordinance
• Building local stormwater programs—we have been working hard to help communities, particularly NPDES Phase II communities, build their local programs
• Stormwater retrofitting—usually as part of a more comprehensive watershed assessment and planning project
• Outfall mapping and IDDE—usually as part of a more comprehensive watershed assessment and planning project
• Estimating pollutant load reductions—simple modeling of watershed treatment scenarios
• Installation and Construction Referrals—we often partner with engineering firms that design and  install Center identified BMPs in its stormwater management projects

We are always looking for opportunities to apply our extensive stormwater knowledge.  Please contact David Hirschman - djh @ cwp.org - for more information on our stormwater services.  Also, check out our extensive resources on www.stormwatercenter.net.

Representative projects include:

Post Construction Program Guidance Document (2008) Through EPA Office of Wastewater Management support, the Center is working with Tetra Tech, Inc to produce post-construction stormwater guidance, targeted to communities across the country that must comply with NPDES requirements. The project involved a survey of over 90 Phase I and II programs in 30 states, and will result in a new guidance document for building and improving programs and local ordinances. 

Coastal Stormwater Supplement (2008) A project with the Georgia Department of Natural Resources and the Chatham County-Savannah Metropolitan Planning Commission, the Center is developing a Coastal Stormwater Supplement (CSS) to the Georgia Stormwater Management Manual. The initial phase of the project was a technical memorandum that summarizes the Center’s most recent research on the impacts of urbanization on coastal aquatic resources and the factors that influence stormwater BMP design and performance in the coastal plain. The technical memorandum provides recommendations and technical background for the CSS, which will be developed during the second phase of the project.

Stormwater Guidelines for Maui County, Hawaii (2006)  The Center developed unique design guidelines to effectively treat stormwater runoff in a challenging island environment. Design guidelines were prepared for ponds, wetlands, bioretention, infiltration and swales that can work in regions with thin soils, high ET and annual rainfall that can span from 10 to 200 inches in the same island. The project focused on design techniques that use native island materials, prevent spread of invasive plants, and remove sediments and pollutants entering sensitive coral reefs.

Minnesota Stormwater Design Manual (2005)  The Center worked with Minnesota-based Emmons & Olivier Resources, a large committee of state regulators, and other stakeholders to craft the Minnesota Stormwater Manual, the most comprehensive one in the Upper Midwest to date.  This manual provides an updated discussion of cold climate issues as they influence design of stormwater practices, like the challenge of high snowfall, springtime snowmelt, and Minnesota’s thousands of sensitive lakes, trout streams, and wetlands that merit special protection. The Center took part in more than a dozen stakeholder meetings, helped respond to more than 1,300 comments, and helped prepare ten issue papers on key technical topics to guide the stakeholders toward consensus and acceptance of the manual. These issue papers introduced new stormwater concepts to the state, such as unified sizing criteria, special receiving water performance standards, and stormwater credits. Training materials that the Center also helped develop will be used throughout the state to educate its diverse population.

District of Columbia Stormwater Guidebook  (2001 & 2008)  The Center reviewed and updated the District of Columbia’s 1994 Draft Storm Water Guidebook. The new guidebook contains sizing criteria for water quality, overbank flood control, and extreme flood control for new development. The DC manual emphasized the range of structural BMPs most appropriate for implementation in the highly-urbanized District, including filtering systems, infiltration practices, and underground storage practices. For each practice, the Center developed feasibility, conveyance, pretreatment, treatment, landscaping, and maintenance criteria.  The Center is currently working with the District to update this manual.

Horry County, SC Stormwater Management and Sediment Control Ordinance Review (2004) The Center conducted an in-depth review of Horry County’s stormwater and sediment control ordinances, focused on the structure and content of the ordinance to ensure that key elements were addressed, including applicability and waivers, reference to a technical manual, application requirements, plan elements, inspection and maintenance requirements, and enforcement procedures. The review assessed the ability of county ordinance to comply with the NPDES Phase II requirements for construction site runoff control, post-construction runoff control, and illicit discharge detection and elimination. A comparison of other state ordinances was also provided. 

Critical Area 10% Rule Guidance Manual (2003) This is the third update Center staff have prepared on the nation’s first guidance requiring specific stormwater phosphorus reductions for new development sites in the Maryland Critical Area, which extends 1000 feet landward of mean high tide in the Chesapeake Bay and Coastal Bays. This guidance manual provides a step-by-step method to account for phosphorus loadings from new development, and reductions by various kinds and sizes of urban stormwater treatment practices. The manual also provides methods to achieve compliance through offsets and fees-in-lieu. 

Center for Watershed Protection © 2008
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