NJDEP retained Najarian Associates to conduct a detailed water quality modeling study of New Jersey’s largest water supply system – the Wanaque Reservoir.  The goal of this study was to support NJDEP’s efforts to develop Total Maximum Daily Loads (TMDLs) for the Reservoir.  TMDLs – measures of the capacity of a waterbody to assimilate specific pollutant loadings — provide a mechanism for identifying all contributors to water quality impacts, and for setting load-reduction goals to meet either existing surface water quality standards or an alternate endpoint criterion.  In this case, NJDEP determined that TMDLs were needed to limit Reservoir impacts due to phosphorus-rich diversion inflows from the Passaic, Pompton and Ramapo Rivers.

Having developed a new hydrothermal model for the Reservoir (ASCE Journal of Hydraulic Engineering, Vol. 120, No. 7), and having applied a companion water quality model to the Reservoir, Najarian Associates was in a unique position to expedite the required TMDL analyses.  Working with NJDEP staff, Najarian Associates assessed several candidate TMDL endpoints criteria, and simulated various load-reduction scenarios targeting the selected endpoint criterion.  Results of these analyses provided a matrix of possible “tradeoffs” in load reductions among river-diversion sources and tributary inflows.  NJDEP incorporated these results into a proposed TMDL published in the July 5, 2005 New Jersey Register.