description: Topographic contours at intervals of 2 feet, covering the Town of Ulysses in Tompkins County, New York. These elevation contours were derived from LiDAR data collected in May 2008.; abstract: Topographic contours at intervals of 2 feet, covering the Town of Ulysses in Tompkins County, New York. These elevation contours were derived from LiDAR data collected in May 2008.

description: Topographic contours at intervals of 2 feet, covering the Town of Dryden in Tompkins County, New York. These elevation contours were derived from LiDAR data collected in May 2008.; abstract: Topographic contours at intervals of 2 feet, covering the Town of Dryden in Tompkins County, New York. These elevation contours were derived from LiDAR data collected in May 2008.

2-ft contour lines for the city, based on 2006 imagery.

Topographic contours at intervals of 2 feet, covering the Town and City of Ithaca in Tompkins County, New York. These elevation contours were derived from LiDAR data collected in May 2008.

Note: The files can be downloaded from the Attachments section below. Please note that the total size is 180GB, so the download may take some time depending on your system’s capabilities and configuration.

Topographic and bathymetric LiDAR data was collected for New York City in 2017. Topographic data was collected for the entire city, plus an additional 100 meter buffer, using a Leica ALS80 sensor equipped to capture at least 8 pulse/m². Dates of capture for topographic data were between 05/03/2017 and 05/17/2017 during 50% leaf-off conditions. Bathymetric data was collected in select areas of the city (where bathymetric data capture was expected) using a Riegl VQ-880-G sensor equipped to capture approximately 15 pulses/m² (1.5 Secchi depths). Dates of capture for bathymetric were between 07/04/2017 - 07/26/2017. LiDAR data was tidally-coordinated and captured between mean lower low water (+30% of mean tide) ranges.

The horizontal datum for all datasets is NAD83, the vertical datum is NAVD88, Geoid 12B, and the data is projected in New York State Plane - Long Island. Units are in US Survey Feet. To learn more about these datasets, visit the interactive “Understanding the 2017 New York City LiDAR Capture” Story Map -- https://maps.nyc.gov/lidar/2017/ Please see the following link for additional documentation on this dataset -- https://github.com/CityOfNewYork/nyc-geo-metadata/blob/master/Metadata/Metadata_LiDAR_Summary.md

This layer is a component of CADWMS.

Detailed 2-foot contour lines and planimetric features such as buildings, paved surfaces (including sidewalks, parking lots, driveways and the edge of pavement) and street centerlines are included in this map service. Environmental features such as wetlands and soil type delineation can also be viewed using this map service.

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals. This dataset contains the raster surface.

This layer is a component of CADWMS.

Detailed 2-foot contour lines and planimetric features such as buildings, paved surfaces (including sidewalks, parking lots, driveways and the edge of pavement) and street centerlines are included in this map service.

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals.

The U.S. Geological Survey (USGS) is providing online maps of water-table and potentiometric-surface altitude in the upper glacial, Magothy, Jameco, Lloyd, and North Shore aquifers on Long Island, New York, April May 2016. Also provided is a depth-to-water map for Long Island, New York, April May 2016. The USGS makes these maps and geospatial data available as REST Open Map Services (as well as HTTP, JSON, KML, and shapefile), so end-users can consume them on mobile and web clients. A companion report, U.S. Geological Survey Scientific Investigations Map 3398 (Como and others, 2018; https://doi.org/10.3133/sim3398) further describes data collection and map preparation and presents 68x22 in. Portable Document Form (PDF) versions, 4 sheets, scale 1:125,000.

The USGS, in cooperation with State and local agencies, systematically collects groundwater data at varying measurement frequencies to monitor the hydrologic conditions on Long Island, New York. Each year during April and May, the USGS completes a synoptic survey of water levels to define the spatial distribution of the water table and potentiometric surfaces within the three main water-bearing units underlying Long Islandthe upper glacial, Magothy, and Lloyd aquifers (Smolensky and others, 1989)and the hydraulically connected Jameco (Soren, 1971) and North Shore aquifers (Stumm, 2001). These data and the maps constructed from them are commonly used in studies of the hydrology of Long Island and are used by water managers and suppliers for aquifer management and planning purposes. Sheets 1 4 in U.S. Geological Survey Scientific Investigations Map 3398 (Como and others, 2018; https://doi.org/10.3133/sim3398) were prepared using water-level data measured at 424 groundwater monitoring wells (observation and supply) and 15 streamgages across Long Island during April and May of 2016. Additionally, digital datasets were derived from the water-level observations that include (1) contour lines and a continuous raster of the depth to water table in the upper glacial and Magothy aquifers, (2) contour lines of the potentiometric surface in the middle to deep Magothy aquifer and the hydraulically connected Jameco aquifer, (3) contour lines of the potentiometric surface in the Lloyd aquifer and hydraulically connected North Shore aquifer, and (4) point feature classes for the 424 groundwater-monitoring wells and 15 streamgages where water levels were collected.

Data Sources

Water-level measurements made in 424 monitoring wells (observation and supply wells), 13 streamgages, and 2 lake gages across Long Island during April May 2016 were used to prepare the maps in this report. Groundwater measurements were made by the wetted-tape or electric-tape method to the nearest hundredth of a foot. Many of the supply wells are in continuous operation and, therefore, were turned off for a minimum of 24 hours before measurements were made to allow the water levels in the wells to recover to ambient (nonpumping) conditions. Full recovery time at some of these supply wells can exceed 24 hours; therefore, water levels measured at these wells are assumed to be less accurate than those measured at observation wells, which are not pumped (Busciolano, 2002). In addition to pumping stresses, density differences (saline water) also lower the water levels measured in certain wells (Lusczynski, 1961). In this report, all water-level altitudes are referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29).

Analysis

Contours of water-table and potentiometric-surface altitudes were created using the groundwater measurements. The water-table contours were interpreted using water-level data collected from 13 streamgages, 2 lake gages, 275 observation wells, and 1 supply well screened in the upper glacial aquifer or the shallow Magothy aquifer. The potentiometric-surface contours of the Magothy aquifer were interpreted from measurements at 88 wells (61 observation wells and 27 supply wells) screened in the middle to deep Magothy aquifer and the contiguous and hydraulically connected Jameco aquifer. The potentiometric-surface contours of the Lloyd aquifer were interpreted from measurements at 60 wells (55 observation wells and 5 supply wells) screened in the Lloyd aquifer and the contiguous and hydraulically connected North Shore aquifer. Editing of the geospatial data was done in ArcGIS Desktop (Esri, 2015a) using geographic information system (GIS) tools.

Depth to water map

A GIS was used to create a continuous surface of the water table using an iterative finite-difference interpolation technique (Esri, 2015b) with measurements from 13 streamgages, 2 lake gages, 275 observation wells, 1 supply well, interpreted 10-foot (ft) contour intervals, and the coastline.

The land surface altitude, or topography, was obtained from National Oceanic and Atmospheric Administration (2016). The data were collected using light detection and ranging (lidar) and were used to produce a three-dimensional digital elevation model (DEM). The lidar data have a horizontal accuracy of 1.38 ft and a vertical accuracy of 0.40 ft at a 95-percent confidence level for the open terrain land-cover category. The DEM was developed jointly by the National Oceanic and Atmospheric Administration and the U.S. Geological Survey as part of the Disaster Relief Appropriations Act of 2013 (Pub.L. 113 2, H.R. 152, 127 Stat. 4). Land surface altitude is referenced to the North American Vertical Datum of 1988 (NAVD 88). On Long Island, NAVD 88 is approximately 1 foot higher than NGVD 29.

The continuous surface of the water table was adjusted for the vertical datum differences across Long Island. This surface was then subtracted from the land surface elevation (from the DEM) at the same location. The results are shown as a continuous depth to water-table map.

References Cited

Busciolano, Ronald, 2002, Water-table and potentiometric-surface altitudes of the upper glacial, Magothy, and Lloyd aquifers on Long Island, New York, in March April 2000, with a summary of hydrogeologic conditions: U.S. Geological Survey Water-Resources Investigations Report 01 4165, 17 p., 6 pl.

Como, M.D., Finkelstein, J.S., Simonette L. Rivera, Monti, Jack, Jr., and Busciolano, Ronald, 2017, Water-table and potentiometric-surface altitudes in the upper glacial, Magothy, and Lloyd aquifers of Long Island, New York, April May 2016: U.S. Geological Survey Scientific Investigations Map 3398, 4 sheets, scale 1:125,000, 6-p. pamphlet, https://doi.org/10.3133/sim3398.

Esri, 2015a, ArcMap 10.3.1: Redlands, Calif., Esri, software.

Esri, 2015b, Topo to Raster Tool: Redlands, Calif., Esri, software.

Lusczynski, N.J., 1961, Head and flow of ground water of variable density: Journal of Geophysical Research, v. 66, no. 12, p. 4247 4256.

National Oceanic and Atmospheric Administration, 2016, NCEI Hurricane Sandy digital elevation models: National Centers for Environmental Information, digital data, accessed January 8, 2016, at https://www.ngdc.noaa.gov/mgg/inundation/sandy/sandy_geoc.html

Smolensky, D.A., Buxton, H.T., and Shernoff, P.K., 1989, Hydrologic framework of Long Island, New York: U.S. Geological Survey Hydrologic Investigations Atlas HA 709, 3 sheets, scale 1:250,000.

Soren, Julian, 1971, Results of subsurface exploration in the mid-island area of western Suffolk County, Long Island, New York: Oakdale, N.Y., Suffolk County Water Authority, Long Island Resources Bulletin 1, 60 p.

Stumm, Frederick, 2001, Hydrogeology and extent of saltwater intrusion of the Great Neck peninsula, Great Neck, Long Island, New York: U.S. Geological Survey Water-Resources Investigations Report 99 4280, 41 p.

This layer is a component of CADWMS.

Detailed 2-foot contour lines and planimetric features such as buildings, paved surfaces (including sidewalks, parking lots, driveways and the edge of pavement) and street centerlines are included in this map service. Environmental features such as wetlands and soil type delineation can also be viewed using this map service.

This layer is a component of CADWMS.

Detailed 2-foot contour lines and planimetric features such as buildings, paved surfaces (including sidewalks, parking lots, driveways and the edge of pavement) and street centerlines are included in this map service. Environmental features such as wetlands and soil type delineation can also be viewed using this map service.

These data were collected in April of 2000 for the Cayuga County New York Department of Planning and Economic Development. Elevation points were sampled at densities necessary to support the generation of contours that meet or exceed United States National Map Accuracy Standards applicable to the map scales that County tax maps are published and for the following intervals of contour lines to be depicted: four feet for the entire county, two feet for the City of Auburn and adjacent area and two feet for six floodplain areas. This is a bare earth data set. There are points returned from water surfaces. Point spacing is approximately 5 m. Also, there are areas in the county where the data have been regularized, i.e. gridded points.

description: Light Detection and Ranging (LiDAR) data is remotely sensed high-resolution elevation data collected by an airborne collection platform. This LiDAR dataset is a survey of areas of coastal New York, including Long Island, eastern Westchester, and the tidal extents of the Hudson River. The project area consists of approximately 950 square miles. The project design of the LiDAR data acquisition was developed to support a nominal post spacing of 1.0 meter or better (1.0 meter GSD). The LiDAR data vertical accuracy is in compliance with the National Standard for Spatial Data Accuracy (NSSDA) RMSE estimation of elevation data in support of 1 ft. contour mapping products. GMR Aerial Surveys Inc. d/b/a Photo Science, Inc. acquired 740 flight lines in 63 lifts between November 2011 and April 2012, while no snow was on the ground, rivers were at or below normal levels, no strong onshore winds, high waves, floods, or other anomalous weather conditions. Specified areas of the project were collected at a tide stage where water levels are at least 1-foot below mean sea level (MSL). This collection was a joint effort by the NOAA Office for Coastal Management (OCM) and the New York State Department of Environmental Conservation. The data collection was performed with three Cessna 206 single engine aircrafts, utilizing Optech Gemini sensors; collecting multiple return x, y, and z as well as intensity data. The data were classified as Unclassified (1), Ground (2), Low Point (Noise) (7), Water (9), Breakline Edge (10), Withheld (11), Tidal Water (14), Overlap Default (17), and Overlap Ground (18), Overlap Water (25), and Overlap Tidal Water (30). Upon receipt, the NOAA Office for Coastal Management (OCM), for data storage and Digital Coast provisioning purposes, converted these classifications to the following: 1 - Unclassified 2 - Ground 7 - Low Point (Noise) 9 - Water NOAA tide gauges were used as the basis for flight planning the tidally coordinated areas. The Stevens Institute NY Harbor Observation and Prediction System (NYHOPS) data were used to confirm accuracy of NOAA predicted tides in Hudson. Some areas were collected using tidal restraints as listed below: Tidal Wetlands and tributary mouths selected for tidal coordination at Mean Sea Level (MSL) minus 1 foot were: Rondout Creek Outlet; Vanderburg Cove, Moodna Creek, Constitution Marsh, Iona Marsh, Annsville Creek, Croton River Outlet, Marlboro Marsh, Manitou Marsh, Fishkill Creek Outlet, and Wappingers Creek Outlet. The Upper Hudson area from North of Goose Island was also collected to the same specification. Tidal Wetlands and tributary mouths selected for tidal coordination at Mean Sea Level (MSL) were Haverstraw at Minisceongo Creek and Piermont Marsh. On Long Island the following areas were collected at MSL: 1) the northern shore of Nassau and Suffolk counties from approximately Glen Cove on the western boundary to Nissequogue on the eastern boundary 2) the Peconic Bay from Riverhead on the western boundary to the east end of Shelter Island and Accabonac Harbor on the eastern boundary 3) western Great South Bay. The remainder of the project area had no tidal restrictions for collection. LAS tiles indicate if they are tidally coordinated or not. If tidal coordination only covers part of the tile the tile will be labeled tidally coordinated (i.e.MSL-1). In order to post process the LiDAR data to meet task order specifications, Photo Science, Inc. established a total of 81 control points that were used to calibrate the LiDAR to known ground locations established throughout the New York project area. Trimble R8-3 GNSS receivers were used to complete the collection. Real Time Kinematic (RTK) survey methodology was typically performed using the New York State Spatial Reference Network (NYSNet), a CORS/Real Time GPS Network. Additionally, control values from various other projects completed by Photo Science in and around the project area, were used as supplemental control points to assist in the calibration of the LiDAR dataset. The dataset was developed based on a horizontal projection/datum of UTM NAD83 (NSRS2007), UTM Zone 18, meters and vertical datum of NAVD1988 (GEOID09), meters. Upon receipt, for data storage and Digital Coast provisioning purposes, the NOAA Office for Coastal Management converted the data to GRS80 Ellipsoid (GEOID09) heights, to geographic (NAD83, NSRS2007) coordinates, and from las format to laz format. LiDAR data were collected in RAW flightline swath format, processed to create Classified LAS 1.2 files formatted to 2093 individual 750m x 750m tiles, Hydro Flattening Breaklines in ESRI shapefile format, 1.0 meter gridded Tidal Water ERDAS IMAGINE (.img) files formatted to 670 individual 3000m x 3000m tiles, and 1.0 meter gridded V-Datum ERDAS IMAGINE (.img) files formatted to the same 3000m x3000m tile schema. LiDAR data were originally delivered to NOAA/Dewberry for quality control validation under Delivery Lots 1 and 2. The lineage (data quality), positional, content (completeness), attribution, logical consistency, and accuracies of all digital elevation data produced conform to the specifications stipulated in NOAA Task Order EA133C11CQ0009 - T011.; abstract: Light Detection and Ranging (LiDAR) data is remotely sensed high-resolution elevation data collected by an airborne collection platform. This LiDAR dataset is a survey of areas of coastal New York, including Long Island, eastern Westchester, and the tidal extents of the Hudson River. The project area consists of approximately 950 square miles. The project design of the LiDAR data acquisition was developed to support a nominal post spacing of 1.0 meter or better (1.0 meter GSD). The LiDAR data vertical accuracy is in compliance with the National Standard for Spatial Data Accuracy (NSSDA) RMSE estimation of elevation data in support of 1 ft. contour mapping products. GMR Aerial Surveys Inc. d/b/a Photo Science, Inc. acquired 740 flight lines in 63 lifts between November 2011 and April 2012, while no snow was on the ground, rivers were at or below normal levels, no strong onshore winds, high waves, floods, or other anomalous weather conditions. Specified areas of the project were collected at a tide stage where water levels are at least 1-foot below mean sea level (MSL). This collection was a joint effort by the NOAA Office for Coastal Management (OCM) and the New York State Department of Environmental Conservation. The data collection was performed with three Cessna 206 single engine aircrafts, utilizing Optech Gemini sensors; collecting multiple return x, y, and z as well as intensity data. The data were classified as Unclassified (1), Ground (2), Low Point (Noise) (7), Water (9), Breakline Edge (10), Withheld (11), Tidal Water (14), Overlap Default (17), and Overlap Ground (18), Overlap Water (25), and Overlap Tidal Water (30). Upon receipt, the NOAA Office for Coastal Management (OCM), for data storage and Digital Coast provisioning purposes, converted these classifications to the following: 1 - Unclassified 2 - Ground 7 - Low Point (Noise) 9 - Water NOAA tide gauges were used as the basis for flight planning the tidally coordinated areas. The Stevens Institute NY Harbor Observation and Prediction System (NYHOPS) data were used to confirm accuracy of NOAA predicted tides in Hudson. Some areas were collected using tidal restraints as listed below: Tidal Wetlands and tributary mouths selected for tidal coordination at Mean Sea Level (MSL) minus 1 foot were: Rondout Creek Outlet; Vanderburg Cove, Moodna Creek, Constitution Marsh, Iona Marsh, Annsville Creek, Croton River Outlet, Marlboro Marsh, Manitou Marsh, Fishkill Creek Outlet, and Wappingers Creek Outlet. The Upper Hudson area from North of Goose Island was also collected to the same specification. Tidal Wetlands and tributary mouths selected for tidal coordination at Mean Sea Level (MSL) were Haverstraw at Minisceongo Creek and Piermont Marsh. On Long Island the following areas were collected at MSL: 1) the northern shore of Nassau and Suffolk counties from approximately Glen Cove on the western boundary to Nissequogue on the eastern boundary 2) the Peconic Bay from Riverhead on the western boundary to the east end of Shelter Island and Accabonac Harbor on the eastern boundary 3) western Great South Bay. The remainder of the project area had no tidal restrictions for collection. LAS tiles indicate if they are tidally coordinated or not. If tidal coordination only covers part of the tile the tile will be labeled tidally coordinated (i.e.MSL-1). In order to post process the LiDAR data to meet task order specifications, Photo Science, Inc. established a total of 81 control points that were used to calibrate the LiDAR to known ground locations established throughout the New York project area. Trimble R8-3 GNSS receivers were used to complete the collection. Real Time Kinematic (RTK) survey methodology was typically performed using the New York State Spatial Reference Network (NYSNet), a CORS/Real Time GPS Network. Additionally, control values from various other projects completed by Photo Science in and around the project area, were used as supplemental control points to assist in the calibration of the LiDAR dataset. The dataset was developed based on a horizontal projection/datum of UTM NAD83 (NSRS2007), UTM Zone 18, meters and vertical datum of NAVD1988 (GEOID09), meters. Upon receipt, for data storage and Digital Coast provisioning purposes, the NOAA Office for Coastal Management converted the data to GRS80 Ellipsoid (GEOID09) heights, to geographic (NAD83, NSRS2007) coordinates, and from las format to laz format. LiDAR data were collected in RAW flightline swath format, processed to create Classified LAS 1.2 files formatted to 2093 individual 750m x 750m tiles, Hydro Flattening Breaklines in ESRI shapefile format, 1.0 meter gridded Tidal Water ERDAS IMAGINE (.img) files formatted to 670 individual 3000m x 3000m

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals. This dataset contains the raster surface.

Static flood inundation boundary extents were created along the entire shoreline of Lake Ontario in Cayuga, Jefferson, Monroe, Niagara, Orleans, Oswego, and Wayne Counties in New York by using recently acquired (2007, 2010, 2014, and 2017) light detection and ranging (lidar) data. The flood inundation maps, accessible through the USGS Flood Inundation Mapping Program website at https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-mapping-fim-program, depict estimates of the areal extent and water depth of shoreline flooding in 8 segments corresponding to adjacent water-surface elevations (stages) at 8 USGS lake gages on Lake Ontario. This item includes data sets for segment B - Lake Ontario at Hamlin Beach State Park near North Hamlin, NY (station number 04220209). These datasets demonstrate the estimated extent and depth of lake flooding at specific water levels of 1-foot increments from 247.0 ft to 251.0 ft (International Great Lakes Datum of 1985). In this study, wind and seiche effects were not represented; therefore, the flood inundation maps reflect five stages for Lake Ontario that are static for the entire shoreline area of the lake. This item is a package of flood inundation data for segment B - Lake Ontario at Hamlin Beach State Park near North Hamlin, NY (station number 04220209) including: 1) 1 shapefile showing 5 estimated flood extents as polygons, 2) 5 raster datasets showing the depth of the water at 5 flood stages, 3) 1 shapefile showing the study limit extent of segment B, and 4) a metadata file. The polygon flood extent shapefiles were developed from digital elevation models (DEMs) derived from the lidar to represent the estimated areal extent for five flood stages for segment B. The raster files depict the depth, in feet, of the water in the inundated areas along the shoreline of Lake Ontario during the five theoretical flood stages. The depth grids were created by subtracting the digital elevation model (DEM) values (in feet) from each of five raster files representing the flood extent at each constant water level (in feet). An approximately 100-meter buffer was used as the extent into the lake. First posted June 21, 2021, ver 1.0 Revised November 2021, ver 2.0 Version 2.0: This version of the dataset has the same data as version 1.0, but some shapefile attributes were renamed to be more accurate and clearer, and the depth-grid rasters were renamed to include the associated water surface elevation within the raster file name. Detailed version history is included in Version_History_LakeOntarioFIMDataRelease.txt. Version 1.0: This version is a package of flood inundation data for Lake Ontario including: 1) 8 shapefiles showing 40 estimated flood extents as polygons, 2) 40 raster datasets showing the depth of the water at 5 flood stages, divided into 8 shoreline segments, 3) 8 shapefiles showing the study limit extent of each segment, and 4) a metadata file.

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals.

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals.

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals.

From 2013 to 2015, bathymetric surveys of New York City’s six West of Hudson reservoirs (Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie) were performed to provide updated capacity tables and bathymetric maps. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system (RTK-GPS) along planned transects at predetermined intervals for each reservoir. A separate set of echo sounder data was collected along transects at oblique angles to the main transects for accuracy assessment. Field survey data was combined with water-surface elevations in a geographic information system to create three-dimensional surfaces representing reservoir-bed elevations in the form of triangulated irregular networks (TINs); the TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were used to create bathymetric maps of the reservoirs; contours were mapped at 2-foot intervals and capacity was calculated at 0.01-foot intervals. This dataset contains the mapped contours at 2-ft depth intervals.