THE USE OF A EUTROPHICATION MODEL IN SUPPORT OF A CSO FACILITY PLAN IN JAMAICA BAY, NY

New York City (NYC) develops facility plans for the drainage basins of each of its 14 Water Pollution Control Plants (WPCPs) in order to improve water quality and comply with New York State (NYS) water quality standards. One of the plants, the 26th Ward WPCP, is located in Queens, NY and discharges into Hendrix Creek, a tributary on the northern end of Jamaica Bay. The 26th Ward WPCP drainage basin includes a total of three dead-end creeks that are tributary to Jamaica Bay and receive CSO discharges during rain events. These three tributaries, Fresh, Hendrix and Spring Creeks, have water quality that is not in compliance with the NYS standard for dissolved oxygen (DO) and Fresh Creek does not meet the standard for total coliform (TC) bacteria. In order to aid in the development of a CSO facility plan for these tributaries, a three-dimensional coupled hydrodynamic/water quality model was developed. This model, the North Channel Model (NCM), encompasses the North Channel of Jamaica Bay as well as Paerdegat Basin, Hendrix Creek, Fresh Creek, and Spring Creek. The model framework includes 26 state-variables in order to simulate two phytoplankton groups, nutrient cycling, dissolved oxygen (DO) and pathogens. The model also includes a sediment nutrient flux submodel to directly model sediment oxygen demand (SOD) and nutrient cycling that occurs in the sediment. In addition, the EXTRAN module of the Storm Water Management Model (SWMM) was used to develop the WPCP and CSO discharge volumes under varying WPCP and sewershed conditions. NCM was used to evaluate various CSO abatement alternatives in order to develop a cost-effective alternative that, ideally, would result in compliance with the New York State standards. This paper will present the results of some of the modeling scenarios completed during this project and examine the factors contributing to the DO standard violations.