Reservoir Turbidity Control/Catskill Treatment EIS
HDR, in conjunction with Hazen & Sawyer, is preparing an Environmental Impact Statement (EIS) under the State Environmental Quality Review Act (SEQRA) to evaluate the potential for environmental impacts of the NYCDEP's proposed program for controlling episodic turbidity events in New York City's (city) upstate reservoirs. This EIS is being done so that NYCDEP can continue to maintain high quality drinking water in its water supply system.
The EIS will evaluate existing and planned elements of the city's water supply system that are involved in controlling turbidity including:
Operational and engineering controls at different locations of the water supply system (Catskill and Delaware aqueducts and watersheds and the Kensico Reservoir)
Operation of the new Croton Water Treatment Plant, implementation of an Operations Support Tool that integrates water quality data with modeling tools to provide near real-time guidance to operations staff, and the City's watershed protection program
The combination of these elements is predicted to result in minimizing the frequency, duration, and quantity of aluminum sulfate (alum) that is added at the inlet to Kenscio Reservoir. The alum is added to settle out high levels of solids that result periodically when extreme rainfall and flooding events cause these solids to become suspended in the watershed runoff and ultimately enter the reservoir.
HDR will evaluate a full range of potential environmental impacts that include: land use, zoning and public policy, socioeconomic conditions, open space, cultural resources, visual resources, aquatic resources, other natural resources, water resources, water quality, infrastructure, energy, solid waste, traffic and safety, air quality, greenhouse gas emissions, noise, hazardous materials, construction impacts, cumulative impacts, environmental justice and public health.
As part of the EIS analysis, HDR conducted aquatic sampling in the Kensico Reservoir. HDR will be conducting water quality modeling of the reservoir, providing support for aquatic sampling and analysis in Lower Esopus Creek near Ashokan Reservoir, and evaluating changes to the NYCDEP's standard operating procedures required to avoid or minimize the need for alum addition.
HDR recently prepared a draft scope of work for the EIS. HDR's scope of work includes public scoping at several locations in the watershed, followed by issuance of a draft and final EIS, and preparation of a Source Pollution Discharge Elimination System (SPDES) permit renewal application for the Kensico Reservoir.