Cedar Grove Brook Stormwater Management Plan
The Cedar Grove Brook (also known as Al's Brook) watershed drains 1,788 acres in northeastern Franklin Township, Somerset County and discharges directly into the Delaware & Raritan Canal approximately three miles upstream of the Canal's terminal spillway located near Landing Lane in the City of New Brunswick. The Cedar Grove Brook watershed is the fourth largest direct drainage to the Canal, and the largest within the last eleven miles of the Canal.
The Cedar Grove Brook Watershed Restoration Plan focused on the identification of management measures to address impacts from existing nonpoint source pollution problems concentrating on stormwater issues. The work included inventorying stream conditions, evaluating existing management practices and determining retrofit opportunities and remedial actions for existing stormwater problems. In addition, a monitoring program was implemented to track down sources of turbidity and identify best management practices (BMPs) to address likely sources of sediment.
The recommended management measures focused on turbidity and total suspended sediment, as those two parameters were identified by the water purveyors as parameters of concern. The field observations, water quality monitoring and modeling indicated that storm events increase the turbidity peaks from Cedar Grove Brook and that the watershed is a source of sediment. The modeling that was conducted did not separate out land sources of sediment from in-stream sources (e.g. bank erosion). The recommendations contained in the restoration plan target land management, in order to reduce the amount of sediment washed from the land into streams, and also will reduce the volume of stormwater entering the streams, thereby reducing bank erosion.