[The following information has been adapted from resources developed by the NJ Dept. of Environmental Protection Division of Watershed Management.]
Watershed Management Area (WMA) 9 includes the mainstem of the Raritan River, the South River, and the Lawrence Brook. The area’s political geography is primarily comprised of Middlesex, Somerset, and Monmouth Counties.
The Raritan River Basin is the largest river basin located entirely in the state of New Jersey. Land use within this basin is mainly urban and suburban with commercial and industrial centers throughout. Despite those impairments, the region is still home to high quality natural areas, like the Watchung Mountains and Pigeon Swamp.
The main stem of the Raritan River spans from the confluence of the North and South Branches to the Raritan Bay. Much of this area is densely populated. There are two low dams on this river: the Fieldsville Dam and the Calco Dam. Among the many small recreational lakes in this region are Watchung Lake, Surprise Lake, Spring Lake, and Green Brook Pond (all man-made lakes).
The South River begins at Duhernal Lake in Spotswood and flows to the Raritan River at Sayreville. It is formed by the confluence of the Manalapan and Matchaponix Brooks. Land use in the subwatersheds associated with those two streams is largely agricultural and wooded. New industrial and commercial development is emerging in this area. Other tributaries include Deep River and Tennants Brook.
In addition to discharges from industrial facilities, construction activities and severe stream bank modification have contributed to sedimentation and localized flooding. Urban runoff from roads, parking lots, and industrial sites has also compromised water quality in some areas.
Watershed Groups and Allies in the Region: