Assessing the Effectiveness of New York City's Watershed Protection Program

To ensure the continued high quality of New York City's (the City) drinking water supply, the Department of Environmental Protection (DEP) developed a comprehensive long-term watershed protection program. Initiated in 1989, this program has provided the basis for a series of waivers from the filtration requirements of the Surface Water Treatment Rule (SWTR) for the Catskill/Delaware supply. The current Filtration Avoidance Determination (FAD), granted in 1997 by the United States Environmental Protection Agency (EPA), will remain in effect until April 2002 when the City will seek renewal of the waiver. As outlined in the SWTR (and Interim Enhanced SWTR), contaminants of concern fall into several categories: coliform bacteria, enteric viruses, Giardia sp., Cryptosporidium sp., turbidity, disinfection by-products, and watershed control. DEP has developed programs to address each of these. With the signing of the Watershed Memorandum of Agreement (MOA) on January 21, 1997, New York City has entered into a new era of watershed protection and partnership with numerous watershed stakeholders. Along with this enhanced watershed protection effort comes a need for the City to ensure that an adequate water quality monitoring and research program is in place to continually evaluate the effectiveness and improve upon the various initiatives contained within the MOA. As such, the MOA specifically requires that the City and New York State (Departments of Health and Environmental Conservation) assess the overall effectiveness of the watershed program in five (5) years time, or by the year 2002. A monitoring strategy and research initiative emphasizing the "Watershed Approach" to water quality management, has been implemented by the City. One of the primary objectives of the monitoring plan will be to allow for a technically sound assessment of the MOA to be accomplished within the required five year period. This paper presents an overview of how information obtained through DEP's extensive array of monitoring and modeling programs may be used to evaluate the effectiveness of water supply protection measures undertaken for the Catskill and Delaware Systems. The sequence of monitoring, watershed program structure development, and evaluation is described. A more detailed description of this program is presented in DEP's 1998 Filtration Avoidance Supplemental Report.