Cedar Grove Brook Watershed-Based 

Stormwater Management Plan

This project includes the development of a stormwater model and management plan for use in regulating new development and identifying potential remedial projects to control pollutant movement to the Canal.  Funding from NJDEP and NJWSA.  Project Partner:  Franklin Township.

Cedar Grove Brook is located in Franklin Township, Somerset County and discharges into the Delaware and Raritan Canal, which provides source water to drinking water purveyors, Middlesex Water, East Brunswick and New Brunswick. These purveyors report increased turbidy and total suspended solids (TSS) in the source water during and following rain events, which requires increased chemical dosing for solids removal, generates greater amounts of sludge, and may create color, taste and odor problems. 

The watershed is more than 80 percent developed with land uses of 40 percent urban, 5 percent agriculture, 21 percent forest, 9 percent barren and 25 percent water and wetlands. Of the entire 18800 arce watershed, 23 percent is classified as preserved. To identify sources of the turbidity and total suspended solids, the Brook was sampled during one low flow and two storm events at six locations and during an additional stormwater event at eight locations. The results indicated that surface water quality standards were generally met for both TSS and turbidity and that concentrations tend to decrease in the downstream portion of the Brook below the in-line Pond at Ukranian Village, near the bottom of the watershed.

 During higher flows and storm events, the sampling results indicate that the Brook is a source of suspended solids (TSS), from stream bank erosion and construction sites, and that these solids settle in the pond. During low flow events, the pond acts as a source of TSS and turbidy, most likely due to algae. The next step in the project is to further examine the watershed for opportunities to remediate existing stormwater problems..

This project focuses on a number of priority issues:

• Protection of the Delaware and Raritan Canal for drinking water supply
• Reduction of total suspended solids, turbidity and associated pollutant loadings to the Delaware and Raritan Canal, and protection/restoration of the stream system
• Management of both existing and future stormwater flows from land uses through a watershed-based stormwater management model and plan
• Use of the results from this project by NJWSA and Franklin Township to ensure a long-term commitment to implementation of this project
• Linkage of project results with NJWSA’s Watershed Protection Program and local efforts in Cedar Grove Brook watershed, to ensure a long-term commitment to project implementation and other steps necessary to protect the Canal

August 2006 Update:

The sampling activities have been completed and the sampling report summary has been submitted for review.  Work has begun on the build-out analyses. GIS coverages of the 2003 landuse/landcover data were obtained from Franklin Township, which contains the entire watershed. The WINSLAMM NPS model is now under development. 

For more information contact Amy L. Shallcross at ashallcross@raritanbasin.org 

NJDEP 319 Grant Project Page