At a Glance

A comprehensive strategy crafted around a new Municipal Separate Storm Sewer System Permit helps one of the most populous counties of the National Capital Region become a water quality leader.

Project Description

Located just north of Washington, DC, Montgomery County, Maryland is home to more than one million people. In 2010, the County, which drains to the Chesapeake Bay, was issued one of the most stringent Municipal Separate Storm Sewer System (MS4) permits in the nation. The five-year permit, which was negotiated with the U.S. Environmental Protection Agency (EPA) and the Maryland Department of the Environmental (MDE) complies with the EPA’s National Pollutant Discharge Elimination System (NPDES) regulations requiring large, urban jurisdictions to control pollution from stormwater runoff to the maximum extent practicable.

In a joint partnership with Brown and Caldwell, Biohabitats has been leading a team of stormwater and marketing consultants to assist the Montgomery County Department of Environmental Protection (DEP) to refine an implementation framework for the MS4 Permit.

The Permit requires development of a Countywide Coordinated Implementation Strategy (CCIS) to meet watershed restoration goals and water quality standards. It also requires the County to evaluate its codes, regulations, standards, policies, and planning process, and develop recommendations to implement Environmental Site Design (ESD) to the maximum extent practicable. Biohabitats was lead consultant and co-author with DEP staff of the County’s CCIS. 

This strategy emphasizes fixing damaged streams, improving water quality, and addressing historical damage caused by urban stormwater pollution.  DEP’s existing watershed restoration efforts are a regulatory requirement of the County’s NPDES MS4 Permit.

Having provided the County with more than a decade of related services, such as stream restoration assessment, design, and construction oversight; development of interagency codes for stormwater management; development of guidelines for stormwater pilots such as raingardens, rain barrels and cisterns, and permeable paving; and capital improvement project identification and prioritization throughout seven watersheds, Biohabitats brought a deep understanding to the MS4 Management contract.

To date, Biohabitats’ work for this two-year base contract (with three possible one-year extensions) has included refining the design process and oversight of eight water resources engineering firms, separately contracted with the County; implementing assessments of five watersheds to identify and prioritize MS4 project opportunities; developing a business management dashboard to track progress of key program performance indicators;  supporting Illicit Discharge Detection and Elimination (IDDE) efforts; and developing a framework for refining GIS-based stormdrain delineations throughout the County.



Chesapeake/Delaware Bays

Physiographic Province



Anacostia River and Potomac River

Expertise Areas

Community, Ecological Restoration, Infrastructure, Urban Ecology, Water


Montgomery County Department of Environmental Protection


Montgomery County, Maryland, United States

Project Team
  • Brown and Caldwell