In a cooperative venture with Maryland Coastal Bays Program and Maryland Department of Natural Resources, Underwood & Associates designed and constructed a project that removed a sheet pile dam in Bishopville, MD and replaced it with a system of weirs. The dam has existed in various configurations since the 1870s along the Bunting Branch of the St. Martin River. It served as a barricade to natural stream flow in this 13.5 square mile drainage area, creating stagnant waters in the five-acre pond, impounding high volumes of sediment and pollutants, and creating an obstacle for migratory species.
The purpose of this project was to restore fish passage to the St. Martin River by establishing an offline pond and 600 linear feet of stream restoration. The stream restoration design increased water storage and treatment through a series of in-stream riffles and pools sized to maintain live flow at a depth appropriate for fish movement. Construction of this project required use of sand bags and pumps to dewater the pond. This project also required work in both the wet and the dry in order to construct riffles above and below the dam.
Removing the dam barrier and installation of the riffles created nearly seven miles of accessible stream for catadromous eels, alewife, and the blueback herring, which have been named three species of concern by National Marines Fishery Service. The project was constructed over a four-month period in late 2014. Within a month of project completion, alewife were seen upstream of the dam.