InterCounty Connector RC131, RC2, NB1 & NB3 Stream Restoration
Biohabitats helped the Maryland State Highway Administration restore four degraded streams in Montgomery County as part of a Compensatory Mitigation/Environmental Stewardship program related to the construction of the state’s Intercounty Connector, an 18-mile highway linking central and eastern Montgomery County with northwestern Prince George’s County.
Over the past several decades, Manor Run, Cherrywood Manor, Mill Creek and Rock Creek had suffered severe bed degradation, bank erosion, straightening, encroachment and habitat loss as a cumulative impact of development in the watershed. Biohabitats’ restoration design needed to reduce sediment input into Manor Run, Cherrywood Manor, Mill Creek, and several tributaries to Mill Creek, as well as into their watershed. It also had to raise the elevation of Rock Creek to facilitate anadramous fish passage. In total, the project would restore more than 25,000 linear feet of stream.
Having studied the streams for several years, Biohabitats developed restoration plans that reconnected the four streams to their historic floodplains and created a series of weirs to provide resting areas and a more gradual transition for fish passing to the upper reaches of the Rock Creek Watershed. The design greatly reduces sediment loss and vastly improves the overall condition and habitat value of the adjacent floodplain.
Biohabitats performed stream assessment, hydrologic and hydraulic modeling, permitting, and design services. The projects involved close coordination with SHA, the Maryland National Capital Park and Planning Commission, the Montgomery County Department of Environmental Protection, the United States Environmental Protection Agency, the U.S. Fish and Wildlife Service, the Washington Suburban Sanitary Commission, the Maryland Department of Natural Resources and the Maryland Department of the Environment.
As part of the review team for SHA, McCormick Taylor provided constructability, erosion and sediment control, and hydraulic modeling review for both projects. The project involved full assessment and design of the entire project length all the while taking into consideration private property, water quality, infrastructure, habitat, and public interests.