Bathymetric data were collected using a boat-mounted Wide Area Augmentation System (WAAS), a type of differential global positioning system, echo depth-sounding equipment, and computer software. Data were exported into a geographic information system and converted into a point layer. These data points were used to create a triangulated irregular network (TIN) from which 2-foot contours were created. The contours were then clipped with a manually digitized outline of the reservoir shoreline and edited for errors. The resulting data was used for mapping purposes and for calculating area and volume statistics.

Water-penetrating LiDAR technology was used to remotely sense bathymetric elevation data as part of a spatial data acquisition on the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area on October 21-24, 2019. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and ArcMap. The GNSS equipment was programmed to continuously collect an observation every second and the ADCP was programmed to continuously collect an observation ranging from every 1 second to 6 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute an elevation of the riverbed.

Water-penetrating LiDAR technology was used to remotely sense bathymetric elevation data as part of a spatial data acquisition on the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area on October 21-24, 2019. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and ArcMap. The GNSS equipment was programmed to continuously collect an observation every second and the ADCP was programmed to continuously collect an observation ranging from every 1 second to 6 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute an elevation of the riverbed.

Bathymetric LiDAR technology was used to collect riverbed elevation data along the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area during October 4-7, 2021. The study area consisted of four verification reaches on the Potomac River including: 1) Williamsport accessed through the Williamsport Park boat ramp below Conococheague Creek and RTE 11 (Williamsport), 2) Big Slackwater above C&O Canal Dam #4 accessed through the Big Slackwater Boat Ramp (Dam4), 3) Four Locks above C&O Canal Dam #5 accessed through the Four Locks Boat Ramp (Dam5), and 4) Little Tonoloway Recreation Area accessed through the Hancock Boat Ramp below RTE 522. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and RStudio. The GNSS equipment was programmed to continuously collect an observation every 1 to 2 seconds and the ADCP was programmed to continuously collect an observation every 1 second to 2 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute the elevation of the riverbed. All spatial data is referenced horizontally to the North American Datum of 1983 (2011) and vertically to the North American Vertical Datum of 1988 (NAVD88). Grid coordinates are projected in Universal Transverse Mercator Zone 18 North and are represented in meter units. This data release consists of four (4) comma-delimited (*.csv) files with fifteen columns each: GNSS_ID, Time_hh_mm_ss, GNSS_Northing_M, GNSS_Easting_M, Computed_Elevation_M, GNSS_Transducer_Elevation_M, Computed_Mean_Depth_M, GNSS_PDOP, GNSS_Vertical Precision_M, GNSS_Satellites, ADCP_Ensemble_ID, ADCP_Temp_C, ADCP_Pitch_Degrees, ADCP_Roll_Degrees, and Type. This data release supersedes a previous version (https://doi.org/10.5066/P9EA0IKM) which contained a constant error of +0.344 meters in the GNSS antenna height reference elevations.

Bathymetric LiDAR technology was used to collect riverbed elevation data along the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area during October 4-7, 2021. The study area consisted of four verification reaches on the Potomac River including: 1) Williamsport accessed through the Williamsport Park boat ramp below Conococheague Creek and RTE 11 (Williamsport), 2) Big Slackwater above C&O Canal Dam #4 accessed through the Big Slackwater Boat Ramp (Dam4), 3) Four Locks above C&O Canal Dam #5 accessed through the Four Locks Boat Ramp (Dam5), and 4) Little Tonoloway Recreation Area accessed through the Hancock Boat Ramp below RTE 522. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and RStudio. The GNSS equipment was programmed to continuously collect an observation every 1 to 2 seconds and the ADCP was programmed to continuously collect an observation every 1 second to 2 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute the elevation of the riverbed. All spatial data is referenced horizontally to the North American Datum of 1983 (2011) and vertically to the North American Vertical Datum of 1988 (NAVD88). Grid coordinates are projected in Universal Transverse Mercator Zone 18 North and are represented in meter units. This data release consists of four (4) comma-delimited (*.csv) files with fifteen columns each: GNSS_ID, Time_hh_mm_ss, GNSS_Northing_M, GNSS_Easting_M, Computed_Elevation_M, GNSS_Transducer_Elevation_M, Computed_Mean_Depth_M, GNSS_PDOP, GNSS_Vertical Precision_M, GNSS_Satellites, ADCP_Ensemble_ID, ADCP_Temp_C, ADCP_Pitch_Degrees, ADCP_Roll_Degrees, and Type. This data release supersedes a previous version (https://doi.org/10.5066/P9EA0IKM) which contained a constant error of +0.344 meters in the GNSS antenna height reference elevations.

Bathymetric LiDAR technology was used to collect riverbed elevation data along the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area during October 4-7, 2021. The study area consisted of four verification reaches on the Potomac River including: 1) Williamsport accessed through the Williamsport Park boat ramp below Conococheague Creek and RTE 11 (Williamsport), 2) Big Slackwater above C&O Canal Dam #4 accessed through the Big Slackwater Boat Ramp (Dam4), 3) Four Locks above C&O Canal Dam #5 accessed through the Four Locks Boat Ramp (Dam5), and 4) Little Tonoloway Recreation Area accessed through the Hancock Boat Ramp below RTE 522. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and RStudio. The GNSS equipment was programmed to continuously collect an observation every 1 to 2 seconds and the ADCP was programmed to continuously collect an observation every 1 second to 2 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute the elevation of the riverbed. All spatial data is referenced horizontally to the North American Datum of 1983 (2011) and vertically to the North American Vertical Datum of 1988 (NAVD88). Grid coordinates are projected in Universal Transverse Mercator Zone 18 North and are represented in meter units. This data release consists of four (4) comma-delimited (*.csv) files with fifteen columns each: GNSS_ID, Time_hh_mm_ss, GNSS_Northing_M, GNSS_Easting_M, Computed_Elevation_M, GNSS_Transducer_Elevation_M, Computed_Mean_Depth_M, GNSS_PDOP, GNSS_Vertical Precision_M, GNSS_Satellites, ADCP_Ensemble_ID, ADCP_Temp_C, ADCP_Pitch_Degrees, ADCP_Roll_Degrees, and Type. This data release supersedes a previous version (https://doi.org/10.5066/P9EA0IKM) which contained a constant error of +0.344 meters in the GNSS antenna height reference elevations.

Bathymetric LiDAR technology was used to collect riverbed elevation data along the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area during October 4-7, 2021. The study area consisted of four verification reaches on the Potomac River including: 1) Williamsport accessed through the Williamsport Park boat ramp below Conococheague Creek and RTE 11 (Williamsport), 2) Big Slackwater above C&O Canal Dam #4 accessed through the Big Slackwater Boat Ramp (Dam4), 3) Four Locks above C&O Canal Dam #5 accessed through the Four Locks Boat Ramp (Dam5), and 4) Little Tonoloway Recreation Area accessed through the Hancock Boat Ramp below RTE 522. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and RStudio. The GNSS equipment was programmed to continuously collect an observation every 1 to 2 seconds and the ADCP was programmed to continuously collect an observation every 1 second to 2 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute the elevation of the riverbed. All spatial data is referenced horizontally to the North American Datum of 1983 (2011) and vertically to the North American Vertical Datum of 1988 (NAVD88). Grid coordinates are projected in Universal Transverse Mercator Zone 18 North and are represented in meter units. This data release consists of four (4) comma-delimited (*.csv) files with fifteen columns each: GNSS_ID, Time_hh_mm_ss, GNSS_Northing_M, GNSS_Easting_M, Computed_Elevation_M, GNSS_Transducer_Elevation_M, Computed_Mean_Depth_M, GNSS_PDOP, GNSS_Vertical Precision_M, GNSS_Satellites, ADCP_Ensemble_ID, ADCP_Temp_C, ADCP_Pitch_Degrees, ADCP_Roll_Degrees, and Type.

Bathymetric LiDAR technology was used to collect riverbed elevation data along the Potomac River. In support of this effort, a bathymetric survey with a boat-mounted acoustic Doppler current profiler (ADCP) was conducted in the study area during October 4-7, 2021. The study area consisted of four verification reaches on the Potomac River including: 1) Williamsport accessed through the Williamsport Park boat ramp below Conococheague Creek and RTE 11 (Williamsport), 2) Big Slackwater above C&O Canal Dam #4 accessed through the Big Slackwater Boat Ramp (Dam4), 3) Four Locks above C&O Canal Dam #5 accessed through the Four Locks Boat Ramp (Dam5), and 4) Little Tonoloway Recreation Area accessed through the Hancock Boat Ramp below RTE 522. Global Navigational Satellite Systems (GNSS) were used to concurrently collect survey grade real-time kinematic (RTK) horizontal and vertical coordinates of the ADCP transducer face. The riverbed elevations were collected using the ADCP with WinRiverII to export for post-processing in Microsoft Excel and RStudio. The GNSS equipment was programmed to continuously collect an observation every 1 to 2 seconds and the ADCP was programmed to continuously collect an observation every 1 second to 2 seconds. The corrected depths from the 4 ADCP beams were averaged and then subtracted from the GNSS derived elevation of the ADCP transducer face to compute the elevation of the riverbed. All spatial data is referenced horizontally to the North American Datum of 1983 (2011) and vertically to the North American Vertical Datum of 1988 (NAVD88). Grid coordinates are projected in Universal Transverse Mercator Zone 18 North and are represented in meter units. This data release consists of four (4) comma-delimited (*.csv) files with fifteen columns each: GNSS_ID, Time_hh_mm_ss, GNSS_Northing_M, GNSS_Easting_M, Computed_Elevation_M, GNSS_Transducer_Elevation_M, Computed_Mean_Depth_M, GNSS_PDOP, GNSS_Vertical Precision_M, GNSS_Satellites, ADCP_Ensemble_ID, ADCP_Temp_C, ADCP_Pitch_Degrees, ADCP_Roll_Degrees, and Type.

These data are high-resolution bathymetry (lake bottom elevation) in a gridded XYZ format, generated from hydrographic surveys of Morse and Geist Reservoirs in April and May of 2016. Hydrographic data were collected using a multibeam echo-sounder (MBES) with integrated inertial navigation solution (INS) mounted on a marine survey vessel. Data were collected as the vessel traversed the lake along survey lines distributed throughout the area. Data collection software integrated and stored the depth data from the multibeam sonar and the horizontal and vertical position and attitude data of the vessel from the INS in real time. In the shallow areas, additional data were collected with an acoustic Doppler current profiler (ADCP) and a real-time kinematic global positioning system (GPS). Data processing required computer software to extract bathymetry data from the raw data files and to summarize and map the information.

These data are high-resolution bathymetry (lake bottom elevation) in a gridded XYZ format, generated from hydrographic surveys of Morse and Geist Reservoirs in April and May of 2016. Hydrographic data were collected using a multibeam echo-sounder (MBES) with integrated inertial navigation solution (INS) mounted on a marine survey vessel. Data were collected as the vessel traversed the lake along survey lines distributed throughout the area. Data collection software integrated and stored the depth data from the multibeam sonar and the horizontal and vertical position and attitude data of the vessel from the INS in real time. In the shallow areas, additional data were collected with an acoustic Doppler current profiler (ADCP) and a real-time kinematic global positioning system (GPS). Data processing required computer software to extract bathymetry data from the raw data files and to summarize and map the information.