Jonathan Casey Root Jane F. Denny William W. Danforth Steve M. Colman 20260331 raster digital data Reston, VA U.S. Geological Survey https://doi.org/10.5066/P14KZS2D Bear Lake is a large freshwater lake that formed through tectonism in a half-graben valley across the Utah and Idaho border. It serves as a critical water resource by storing water and regulating Bear River flows that support downstream ecosystems and agriculture in the Great Salt Lake basin. This data release includes an assimilated topobathymetric raster of Bear Lake comprising interpolated bathymetry from 2002 (Denny and Colman, 2003) and Quality Level 1 lidar from 2016 (Utah Geospatial Resource Center, 2016) and 2018 (Utah Geospatial Resource Center, 2018), and the results of an elevation-area-volume assessment. Denny and Colman (2003) compiled a detailed bathymetric map and provided contour data for use in geospatial information systems; the raw point data from this survey were used for this data release to interpolate the bathymetry of Bear Lake. The topobathymetric dataset was generated with a horizontal projection of UTM Zone 12N, North American Datum of 1983, Geoid 12b at a 0.5-meter horizontal resolution, and referenced to the North American Vertical Datum of 1988 (NAVD88) in meters. Relationships between elevation with area and volume were calculated on the U.S. Geological Survey's Hovenweep high performance computer (Falgout and others, 2023) at 0.01-meter intervals from the bottom of Bear Lake (1747.39 meters above NAVD88) to 1808.00 meters above NAVD88 which is approximately the elevation of the highways and roads that surround Bear Lake. The purpose of this dataset is to provide updated topobathymetry of Bear Lake for use in geographic information systems. Area and volume calculations were done in support of studies on water quality and evaporation models for Bear Lake. 20020904 20180701 ground condition Complete None planned Bear Lake in Utah and Idaho -111.4335 -111.2464 42.1278 41.8211 ISO 19115 Topic Category elevation geoscientificInformation inlandWaters society USGS Thesaurus topography digital elevation models bathymetry geospatial analysis None topobathymetric digital elevation model TBDEM DEM elevation USGS U.S. Geological Survey 3D Elevation Program 3DEP topobathymetry Light Detection and Ranging lidar Utah Water Science Center Acoustic Sonar Inland Bathymetry Reservoir Storage Capacity Flood Inundation Modeling USGS Metadata Identifier USGS:698226f4b66b018d00102e42 Geographic Names Information System (GNIS) Bear Lake Utah Idaho Wasatch Range Bear River Range Bear River Bear River Canal Big Creek Little Creek Spring Creek Indian Creek Cheney Creek Fish Haven Creek Swan Creek Mud Lake Rich County Bear Lake County Garden City Town of Garden City Pickelville Fish Haven Lifton Rendezvous Beach Ideal Beach Bear Lake Hot Springs None. Please see 'Distribution Info' for details. These data are marked with a Creative Common CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov Jane F. Denny Steve M. Colman 2003 publication Reston, VA U.S. Geological Survey https://doi.org/10.3133/ofr03150 Utah Geospatial Resource Center 2018 raster digital data https://gis.utah.gov/products/sgid/elevation/lidar/#2018-northern-utah Utah Geospatial Resource Center 2017 raster digital data https://gis.utah.gov/products/sgid/elevation/lidar/#2016-bear-lake-bear-river-cache-valley--upper-weber-valley Jeff T. Falgout Janice Gordon R. Lopaka Lee 2023 dataset https://www.sciencebase.gov U.S. Geological Survey https://doi.org/10.5066/p927bi7r No formal attribute accuracy tests were conducted. No formal logical accuracy tests were conducted. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. DEVELOP DIGITAL ELEVATION MODEL OF BATHYMETRY FROM BATHYMETRIC POINT DATA: Bathymetry of Bear Lake was surveyed September 4–16, 2002, using an SEA Submetrix Series 2000 swath bathymetry sonar (234 kHz) system and real-time differential global positioning system (Denny and Colman, 2003). The raw point data were provided by Denny and Colman (2003) as depths in meters in xyz text file and represent 10-meter spaced grid nodes exported from a grid created using data collected by a phase discriminating bathymetric system. The xyz depth data were imported to ArcGIS Pro (v. 3) as a point shapefile and converted to elevations above the North American Vertical Datum of 1988 (NAVD88) using the median lake level (1802.917908 meters above NAVD88) from USGS lake elevation station 10055000, Bear Lake at State Park Marina NR Garden City, UT. The point data required filtering for errors which were typically along the edges of the survey swaths. Filtering was done by visual inspection and then with the Optimized Outlier Analsys tool in ArcGis Pro (v. 3) for deletion (Performance Adjustment: Robust, 999 permutations). This tool creates a map of statistically significant hot spots, cold spots, and spatial outliers using the Anselin Local Moran's I statistic. It evaluates the characteristics of the input feature class to produce optimal results. The point bathymetry data were then interpolated into a 10-meter digital elevation model (DEM) using the Topo to Raster tool in ArcGIS Pro (v. 3). The following inputs were used in Topo to Raster: INPUT FEATURE DATA: ADCP point data (feature class – point elevation); OUTPUT CELL SIZE: 10 m; MARGIN IN CELLS: 100; DRAINAGE ENFORCEMENT: Do not enforce; PRIMARY TYPE OF INPUT DATA: Spot; MAXIMUM NUMBER OF ITERATIONS: 20 (default); ROUGHNESS PENALTY: 0.7; PROFILE CURVATURE ROUGHNESS PENALTY: 0.9; DISCRETISATION ERROR FACTOR: 4; VERTICAL STANDARD ERROR: 3; TOLERANCE 1: 0 (default); TOLERANCE 2: 200 (default). Minimum and maximum elevations reflect the range from the original datasets (1740.06005859–1863.18994141 meters). These parameters were used after testing different interpolations and assessing whether the resultant raster reflected the bathymetric data. 20251101 Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov ASSIMILATE LIDAR WITH INTERPOLATED BATHYMETRY: Topographic Quality Level 1 lidar elevation data were acquired at eight points per meters between October 22–November 19, 2016, by the Utah Geospatial Resource Center (UGRC), Cache and Weber County, and the Utah Department of Emergency Management for the Bear Lake shoreline. The dataset includes a 0.5-meter digital elevation model (DEM) of complete coverage around Bear Lake, with a 10.0 cm root mean square error (RMSE). Small regions on the south and east shores of Bear Lake were not covered by the 2016 lidar and were filled using Quality Level 1 lidar acquired at eight points per meter between June 13–July 1, 2018, by the UGRC, Natural Resource Conservation Service, and the Utah Geological Survey. These two datasets were mosaiced together and clipped to the major roads, including United States Highway 89 and State Route 30 on the west shore, Main Street on the south shore, Cisco Road and East Shore Road on the east shore, and North Beach Road on the north shore nearest to the Bear Lake shoreline; this lowest elevation along this route that encloses Bear Lake equates to approximately 1808.00 meters above the North American Vertical Datum of 1988 (NAVD88). The 2016 lidar data represent an area of 37.57 square kilometers; the 2018 lidar data represent an area of 1.37 square kilometers. The water surface was recorded as 1803.50 meters above NAVD88; the data at this elevation were removed before assimilating the lidar with the bathymetry. A significant gap between the two datasets was present between the lidar, which stopped at the Bear Lake shoreline, and the bathymetry, which was not available in the shallow regions near the shoreline. 20251201 Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov GAP FILLING BETWEEN LIDAR AND BATHYMETRY AND ASSIMILATING SEAMLESS TOPOBATHYMETRY: A gap without overlap existed between the lidar and bathymetry. To fill this gap, the lidar and bathymetry data were interpolated to generate a best-estimate surface in the gap. The lidar and bathymetry raster were converted to point data using the Create Spatial Sampling Locations tool in ArcGIS Pro (v. 3.5.5) with a “Simple random” sampling method to generate five million points with a minimum distance between sample points of 5 meters. The resultant point data was then interpolated using the Topo to Raster tool: INPUT FEATURE DATA: lidar and bathymetry point data (feature class – point elevation); OUTPUT CELL SIZE: 1 meter; MARGIN IN CELLS: 20; DRAINAGE ENFORCEMENT: Do not enforce; PRIMARY TYPE OF INPUT DATA: Spot; MAXIMUM NUMBER OF ITERATIONS: 20 (default); ROUGHNESS PENALTY: 1.0; PROFILE CURVATURE ROUGHNESS PENALTY: 0.5; DISCRETISATION ERROR FACTOR: 2; VERTICAL STANDARD ERROR: 1; TOLERANCE 1: 0 (default); TOLERANCE 2: 200 (default). These parameters were used after testing different interpolations and assessing whether the interpolated raster was similar to the lidar or interpolated bathymetry where there was overlap and whether there were observable aberrations to the topography in the gap. Minimum and maximum elevations reflect the range from the original datasets (1747.40002441–2257.15991211 meters). This interpolated gap-fill raster, which extended to the outer extent of the lidar data, was mosaiced as the bottom layer with the overlapping 0.5-meter lidar and 10-meter bathymetry using the Mosaic to New Raster tool in ArcGIS Pro (v. 3.5.5) and resampled to 0.5 meters. 20260101 Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov ERROR ANALYSIS: The gap-fill interpolation was validated against the lidar and bathymetry where it overlapped. To assess the performance of the gap interpolation, it was tested against the lidar and bathymetry by generating 30,000 random points, with a minimum distance between each point set to 5 meters, by comparing the values of the gap-fill interpolation. The average difference between gap-fill and lidar or bathymetry was 0.038 meters with a 0.411-meter standard deviation, a minimum of -6.440 meters, and a maximum of 9.280 meters. The interpolation performed better against just the bathymetry, with an average difference of 0.001 meters with a 0.045-meter standard deviation, a minimum of -0.380 meters, and a maximum of 0.860 meters. These results may reflect the difference in precision between Quality Level 1 lidar and an interpolated surface which cannot capture real-world irregularities in topography at the sub-meter scale. 20260101 Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov CALCULATE ELEVATION-AREA-VOLUME RELATIONSHIPS: The ESRI Storage Capacity tool, included in the ArcPy Python package, was used to calculate the area and volume of the 0.5-meter Bear Lake topobathymetry at 0.01-meter intervals from 1747.39–1808.00 meters above NAVD88. The Storage Capacity Python script was modified for use on the USGS Hovenweep high performance computer (Falgout and others, 2023) to reduce computational time and minimize the need for interpolating between intervals or resampling to a coarser horizontal resolution. 20260101 Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov Raster Pixel 67999 31269 1 Universal Transverse Mercator 12 0.9996 -111.0 0.0 500000.0 0.0 row and column 0.5 0.5 meters NAD83 (National Spatial Reference System 2011) (EPSG:1116), epoch 2010.00 GRS 1980 (EPSG:7019) 6378137.0 298.257222101004 North American Vertical Datum of 1988 (EPSG:5703), GEOID12B 0.01 meters Explicit elevation coordinate included with horizontal coordinates Bear_Lake_TBDEM_2026_50cm.zip Zipped raster file containing georeferenced tag image file format, or GeoTIFF, of Bear Lake. Producer Defined Value Unique numeric values contained in each raster cell. Producer Defined 1747.3975830078 1863.4399414062 meters above the North American Vertical Datum of 1988 0.01 Bear_Lake_TBDEM_2026_Spatial_Metadata.zip Zipped shapefile containing spatial metadata information detailing source datasets used to create the Bear Lake topobathymetry (TBDEM). Producer Defined FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Shape type. Name Shorthand dataset name Producer Defined bathy Interpolated bathymetry of Bear Lake Producer defined lidar_2018 2018 QL1 lidar around Bear Lake Producer defined lidar_2016 2016 QL1 lidar around Bear Lake Producer defined gap_interp Interpolated gap fill between lidar and bathymetry Producer defined Title Source dataset name Producer Defined 2002 10-meter interpolated bathymetry Interpolated bathymetry of Bear Lake Producer defined 2018 0.5-meter QL1 lidar 2018 QL1 lidar around Bear Lake Producer defined 2016 0.5-meter QL1 lidar 2016 QL1 lidar around Bear Lake Producer defined 2026 0.5-meter shoreline gap interpolation Interpolated gap fill between lidar and bathymetry Producer defined Source Source dataset report name Producer Defined Geophysical Surveys of Bear Lake, Utah-Idaho, September, 2002, OFR 03-150 Geophysical Surveys of Bear Lake, Utah-Idaho, September, 2002, OFR 03-150 Producer defined 2018 Northern Utah 2018 Northern Utah Producer defined 2016 Bear Lake, Bear River, Cache Valley & Upper Weber Valley 2016 Bear Lake, Bear River, Cache Valley & Upper Weber Valley Producer defined Half-meter topobathymetric elevation model and elevation-area-volume tables for Bear Lake, Utah and Idaho, 2002-2018 Half-meter topobathymetric elevation model and elevation-area-volume tables for Bear Lake, Utah and Idaho, 2002-2018 Producer defined Source_Org Organization responsible for collection of data Producer Defined USGS USGS Producer defined Utah Geospatial Resource Center Utah Geospatial Resource Center Producer defined Date_Acq Date data were acquired Producer Defined 2002 Survey year Producer defined 2018 Survey year Producer defined 2016 Survey year Producer defined 2026 Production year Producer defined Date_Pub Year of publication Producer Defined 2003 Year of publication Producer defined 2019 Year of publication Producer defined 2017 Year of publication Producer defined 2026 Year of publication Producer defined Data_Type Input elevation type Producer Defined Interpolated bathymetry from single-beam point bathymetry Interpolated bathymetry from single-beam point bathymetry Producer defined Topographic lidar Topographic lidar Producer defined Interpolated gap between topographic lidar and interpolated bathymetry Interpolated gap between topographic lidar and interpolated bathymetry Producer defined Source_VD Input source vertical datum Producer Defined NAVD88 North American Vertical Datum of 1988 Producer defined Source_Res Input source horizontal resolution Producer Defined 10-meter gridded points; 10-m interpolated raster Source and interpolated resolution Producer defined 0.5 m Source resolution Producer defined Source_HD Input source horizontal datum Producer Defined NAD83 / UTM zone 12N The North American Datum of 1983 (NAD 83); Universal Transverse Mercator, Zone 12 North Producer defined NAD83(2011) / UTM zone 12N The North American Datum of 1983 (NAD 83) with 2011 adjustments; Universal Transverse Mercator, Zone 12 North Producer defined Source_Unt Input source units Producer Defined meters International System of Units Producer defined Source_Geo Input source geoid Producer Defined NA, raw data are depth only Not applicable Producer defined GEOID12B Used to convert the ellipsoidal height obtained by the Global Navigation Satellite System to the orthometric height of a specific vertical datum. The Geoid 12B model transforms between NAD 83 (2011/PA11/MA11) and the respective vertical datums. Producer defined Source_Web Input source web address Producer Defined NA No Data Producer defined https://pubs.usgs.gov/of/2003/of03-150/index.htm Publication web page for the 2002 Bear Lake bathymetry Producer defined https://gis.utah.gov/products/sgid/elevation/lidar/#2018-northern-utah Publication web page for 2018 Northern Utah lidar elevation data Producer defined https://gis.utah.gov/products/sgid/elevation/lidar/#2016-bear-lake-bear-river-cache-valley--upper-weber-valley Publication web page for 2016 Bear Lake lidar elevation data Producer defined Area_acres Area of spatial polygon feature, in acres Producer Defined 339.162 55213.3 acres Area_km2 Area of spatial polygon feature, in square kilometers Producer Defined 1.37255 223.441 square kilometers Bear_Lake_2026_ElevAreaVolume.csv Comma Separated Value (CSV) file containing the elevation-area-volume relationships for the north arm of Bear Lake at 0.01-meter intervals. Producer Defined elev_m_NAVD88 Elevation in meters, referenced to the North American Vertical Datum 1988 (NAVD88). Producer Defined 1747.39 1808.00 meters 0.01 elev_ft_NAVD88 Elevation in feet, referenced to the North American Vertical Datum 1988 (NAVD88). Producer Defined 5732.91 5931.76 feet 0.01 area_ft2 Area in square feet. Producer Defined 0.00 3090129878.96 square feet 0.01 area_m2 Area in square meters. Producer Defined 0.00 287082459.75 square meters 0.01 area_km2 Area in square kilometers. Producer Defined 0.00 287.08 square kilometers 0.01 area_mi2 Area in square miles. Producer Defined 0.00 110.84 square miles 0.01 area_acre Area in acres. Producer Defined 0.00 70939.34 acres 0.01 volume_ft3 Volume in cubic feet. Producer Defined 0.00 287189599828.24 cubic feet 0.01 volume_m3 Volume in cubic meters. Producer Defined 0.00 8132303841.15 cubic meters 0.01 volume_km3 Volume in cubic kilometers. Producer Defined 0.00 8.13 cubic kilometers 0.01 volume_mi3 Volume in cubic miles. Producer Defined 0.00 1.95 cubic miles 0.01 volume_acreft Volume in acre-feet. Producer Defined 0.00 6592972.58 acre-feet 0.01 U.S. Geological Survey - ScienceBase U.S. Geological Survey mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P14KZS2D None 20260331 Jonathan Casey Root USGS Utah Water Science Center Hydrologist mailing and physical

2329 West Orton Circle

West Valley City UT 84119 US 801-908-5043 jroot@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999