Waterbody/Watershed Planning For New York City's Urban Watershed

William E. McMillin, Jr., P.E., John P. St. John, P.E., W. Kurtz, and J. Mueller

New York Harbor and its tributaries form a complex hydrologic network of open waters, embayments, rivers, estuaries, wetlands and riparian areas. The New York State classifications of many of these waterbodies may not be considered to meet the "fishable/swimmable" criteria of the Clean Water Act. Even so, current water quality standards, although lower than fishable/swimmable, are still not attained in many locations throughout the Harbor and its tributaries. The New York City Department of Environmental Protection (DEP) is conducting a multi-phase program to address the impacts of combined sewer overflows (CSOs), wastewater treatment plants (WWTPs), and other pollutant sources on these waterbodies. The Use and Standards Attainment (USA) Project was launched by the DEP in August 1999 as part of its continuing efforts to maintain and improve water quality in New York Harbor and its environs. A watershed-based approach is being utilized to conduct an integrated evaluation of the interdependent factors affecting receiving water uses, including storm water, CSOs, wastewater treatment, upland uses, shoreline uses, habitats, sediment and water quality with the active participation of major stakeholders from the start of the process. Over 25 waterbodies throughout the harbor are being assessed by the USA Project.

A presentation on the USA Project was given at the Water Environment Federation's Watershed 2000 speciality conference. That presentation described New York City's overall urban watershed approach to address waterbody issues. A case study was reviewed of an impacted urban tributary, Paerdegat Basin, that is one of two waterbodies first being assessed by the USA Project. Much has happened during the assessment of Paerdegat Basin and a plan is now being developed. The assessment, the tools utilized, the lessons learned, and a waterbody/watershed plan for Paerdegat Basin will be the subject of the Watershed 2002 presentation.

A major goal of the USA Project is to develop plans to restore, enhance, and protect riparian and waterbody uses as they are affected by water quality. These uses include fish and aquatic life protection, fish and shellfish consumption, wildlife protection, shellfishing, bathing/recreation, aesthetics, and public access - all of which are protected by water quality standards. A variety of resources were used to develop a plan for Paerdegat Basin addressing each of these uses. This included a compilation of existing data, and that collected by other ongoing programs, additional data collection efforts, a scientific review of physical, chemical, and biological data, mathematical modeling, and engineering analyses were all conducted to develop the plan. The plan also addressed evolving regulatory processes such as the U.S. Environmental Protection Agency's dissolved oxygen and nutrient criteria development, long-term CSO planning, and total maximum daily load (TMDL) development.

A state-of-the-science approach has been utilized to address fish and aquatic life protection uses for Paerdegat Basin. This has included a review and application of EPA's Ambient Aquatic Life Water Quality Criteria for Dissolved Oxygen (Saltwater): Cape Cod to Cape Hatteras. A site-specific analysis of water quality conditions was conducted using the model developed by EPA and applying it to aquatic life most appropriate for Paerdegat Basin. Larval growth, larval survival, and juvenile survival were each assessed using data and mathematical modeling to determine how best to restore and protect these uses in the basin given that the DEP is constructing a CSO abatement facility that will store over 50 million gallons and treat overflows. Scientific analyses of ichthyoplankton, epibenthic, sediment grain size, benthic habitat, fish abundance and diversity, water quality, and other data collected during the project contributed to the analysis. Regulatory opportunities were identified such that a recommendation can be made within existing frameworks to best protect identified uses while considering the basin's significance to the greater ecosystem of Jamaica Bay, to which Paerdegat Basin is a tributary.

The assessment also included analyses using Geographic Information Systems (GIS) and other tools that have focused not only on water quality in Paerdegat Basin but also on land characteristics and uses both in the basin's watershed and in its riparian zones. For instance land use characterizations for the entire watershed, within a quarter mile radius, and along riparian zones were identified, characterized, and mapped to build a better understanding of uses around the basin for which waterbody use classifications would be best suited. This included identifying existing and potential levels of recreation for which water quality criteria would be most appropriate of protecting. This information was then shared, reviewed, enhanced, and prioritized with input from a Waterbody Stakeholder Team convened for Paerdegat Basin with members who are local residents and waterbody/riparian users. Existing and potential upgrades of recreational use standards were reviewed and recommendations were developed for the waterbody/watershed plan most consistent with riparian and waterbody uses.

Presented at:

Watershed 2002
Sponsored by the Water Environment Federation
Ft. Lauderdale, Florida

February 26, 2002