Digital elevation model of the Nehalem Bay near Wheeler, Oregon 2019

Bathymetric data were collected by the U.S. Geological Survey (USGS) in 2019 for approximately 2.2 square kilometers of the Nehalem Bay between the Highway 101 bridge and Nehalem Bay State Park (about 6.5 kilometers) near Wheeler, Oregon. The data were collected using a Trimble R8 Global Navigation Satellite System (GNSS) receiver combined with a Seafloor Systems Hydrolite TM single-beam 200 kilohertz echosounder mounted to a motorized boat. GPS positions received corrections in real time from the Oregon Real-Time GNSS Network. Sound velocity profiles were recorded at 19 different locations evenly spaced throughout the survey area using an AML Oceanographic Base X2 100 meter sound velocity profiler in order to quantify the spatial and temporal variation in sound velocity. Data was collected using the UTM Zone 10 North (meters) (NAD83[2011]) coordinate system, with elevations relative to NAVD88 using Geoid 12B. Data was post-processed to remove spurious data points. Raw depths were corrected using the mean value of the recorded sound velocity profiles, then converted to bed elevations. The mean vertical and horizontal uncertainties are 0.04145 and 0.00945 meters, respectively. This product is a GeoTiff raster digital elevation model (DEM) based on the bed elevation data. Bed elevations were used to create a triangulated irregular network (TIN) surface which was edited by adding lines delineating breaks in slope, then converted into a raster with a 20-meter cell size.