ESTIMATING NONPOINT SOURCE POLLUTANT LOADING FOR WATER QUALITY MANAGEMENT PLANNING

Executive Order 109, signed on January 11, 2000, reinforced the New Jersey Department of Environmental Protection's (NJDEP) role in determining what, if any, alternatives analyses must be conducted as part of an application for approval of a wastewater management plan or plan amendment. As a result, the NJDEP, Division of Watershed Management was charged with identifying appropriate measures by which analyses for EO-109 would be conducted for approval. Analyses in this context have included: a nonpoint source pollutant (NPS) loading analysis, hydromodification analysis, riparian buffer analysis, depletive and consumptive water use analysis, and a groundwater quality analysis. The focus of this paper is to discuss the approach taken by the NJDEP to address the NPS analysis. A method commonly used to estimate nonpoint source loads incorporate the use of annual loading or export coefficients (LCs). This method was chosen to estimate pollutant loading from project areas subject to EO-109 to address pre to post-pollutant loading that result from changes in landuse. Given the variability associated with literature LCs for any given pollutant and land use type, the NJDEP entered into a contract with the USEPA, Region 2, for the purpose of developing a tool to identify appropriate LCs for use in New Jersey. The resulting Loading Coefficient Analysis and Selection Tool (LCAST) is a database querying routine that assists in the LC selection process and provides an output matrix of loading coefficients for a specified pollutant and land use. The pollutant loading values generated by LCAST can then be exported and applied using BASINS 3.0 PLOAD for modeling of annual NPS pollutant loading.