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Geospatial bathymetry datasets for New York City's East of Hudson Reservoirs and Controlled Lakes

June 22, 2021

From May 2017 to November 2019, the U.S. Geological Survey conducted bathymetry surveys of New York City's East of Hudson Reservoirs. The East of Hudson Reservoirs consist of 16 reservoirs and controlled lakes in Putnam and Westchester County, New York, including Amawalk Reservoir, Bog Brook Reservoir, Boyd Corners Reservoir, Cross River Reservoir, Croton Falls Reservoir, Diverting Reservoir, East Branch Reservoir, Kensico Reservoir, Kirk Lake, Lake Gilead, Lake Gleneida, Middle Branch Reservoir, Muscoot Reservoir, New Croton Reservoir, Titicus Reservoir, and West Branch Reservoir. The East of Hudson Reservoirs form New York City's Croton Water Supply System, and also include parts of the Catskill/Delaware Water Supply System.

Depth data were collected primarily with a multibeam echosounder; additional bathymetry points were measured using an acoustic Doppler current profiler (ADCP). Quality assurance points were measured with a single-beam echosounder. Water surface elevations were established using real-time kinematic (RTK) and static global navigation satellite system (GNSS) surveys and submersible pressure transducers. Measured sound velocity profiles were used to correct echosounder depth measurements for thermal stratification. Digital elevation models were created by combining the measured bathymetry data with lidar elevation data surrounding the reservoirs; gaps in the combined data were estimated (for example the tops of submerged islands) or interpolated.

Files included in this Data Release include: grids (tiff format) of reservoir bed elevation, data source, and cell data standard deviation; shapefiles of elevation contours at a 2-foot interval and of single-beam echosounder quality assurance points; and text files (comma-separated value format) of elevation-area-capacity tables for each reservoir, measured GNSS points, water surface elevation time series (tides) used to process echosounder data, measured sound velocity profiles, and average sound velocity profiles used to process echosounder data.

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