Lower Delaware River Special Protection Waters Assessment of Measurable Changes to Existing Water Quality, Round 1: Baseline Ewq (2000-2004) vs. Post-Ewq (2009-2011)

Elaine Langone Center, Terrace Room

The Delaware River Basin Commission (DRBC) adopted the Special Protection Waters (SPW) program in 1992 to prevent degradation in the 197-mile non-tidal reach of the Delaware River and its tributaries where existing water quality is better than water quality standards. Under SPW, DRBC defines Existing Water Quality (EWQ) and monitors sites to ensure that established EWQ is being preserved. Data collected by DRBC, and other monitoring agencies, were used to define site-specific EWQ for locations within the non-tidal Delaware River and tributaries. DRBC recently performed an assessment to determine whether changes to EWQ have occurred between the definition period (2000-2004) and the assessment period (2009-2011) at 24 EWQ sites. For most water quality parameters at most locations, there was no degradation to EWQ and evidence of improved nutrient concentrations, demonstrating the importance and effectiveness of DRBC’s Special Protection Waters program. This presentation will describe the SPW program, an overview of the monitoring efforts and methods, and the overall results of this assessment in addition to some examples.