The NJDEP engaged Kleinfelder to help the agency understand and establish baseline water quality conditions within various watersheds, and to provide a basis for establishing total maximum daily loads (TMDLs) throughout three separate watersheds. The three watersheds studied were those associated with the Rancocas Creek, the Passaic River, and the Raritan River. These three watersheds comprise 25% of the area of the State of New Jersey.
The watersheds included a large variety of both hydrologic and pollutant loading conditions, ranging from point source dominated areas with large population centers to areas impacted mostly by agricultural nonpoint sources. While triggered by exceedances of numerical phosphorus criteria, each of these studies included extensive monitoring and assessment in order to evaluate whether phosphorus is causing, or has the potential to cause, instream use impairment. Nutrient chemistry, dissolved oxygen, pH, and algal measurements were used to assess nutrient impacts, identify critical locations, and select suitable TMDL end points.
The TMDL studies provide interesting lessons, including: 1) importance of thorough assessment in identification of impairments and selection of critical locations and end points; 2) nature of impacts of phosphorus reductions from point sources and non-point sources (including stormwater); and 3) ranges of reductions required to satisfy various end points. These studies were the result of an effective partnership among National Pollutant Discharge Elimination System permittees within the various basins and the state. The engineering work was performed on behalf of NJDEP, illustrating the unique capabilities of Kleinfelder to work constructively with regulators toward effective environmental solutions.
The studies produced several outcomes. In the Rancocas Watershed, our conclusions led the NJDEP to choose not to proceed with a full TMDL study. For the Passaic River Basin, our efforts resulted in watershed-specific criteria for discrete locations, rather than broadly applied criteria throughout the basin. The Raritan River Basin TMDL study included several technical innovations, including a novel pollutant loading model.