Topobathymetric Lidar - Clear Lake Tributaries - 2024

The California Department of Fish and Wildlife contracted NV5 Geospatial, Inc. (NV5) to conduct airborne lidar surveys to map the topographic and bathymetric (underwater) terrain in sections of six tributaries to Clear Lake that are known or expected to contain Clear Lake Hitch (Lavinia exilicauda chi) spawning habitat, referred to as the area of interest (AOI). The lidar AOI covers approximately 5,942 acres across roughly 54 stream miles. NV5 acquired the lidar data from April 6th–April 8th 2024, when weather and water conditions were most favorable. Lidar data were acquired using near-infrared wavelength (ʎ=1064 nm) and bathymetric green wavelength (ʎ=532 nm) sensors mounted on a Riegl VQ-880-GII laser platform in a Cessna Grand Caravan aircraft. A PhaseOne iXM-RS150F medium-format digital camera was used to acquire 3-band (red, green, blue) orthoimagery simultaneously with the lidar data. From these data, NV5 produced a classified lidar point cloud and a lidar-derived digital elevation model (DEM). NV5 evaluated the classified, average lidar point densities in the successfully mapped portions of the AOI and found density values of 3.06 points/ft^2 (32.97 points/m^2) for first returns, 1.14 points/ft^2 (12.27 points/m^2) for ground and bathymetric bottom returns, and 1.03 points/ft^2 (11.09 points/m^2) for only bathymetric bottom returns. Where environmental factors (e.g., water turbidity, depth) or physical obstructions (e.g., bridges, vegetation) limited the lidar’s penetration to the ground surface, referred to as void areas, NV5 interpolated the terrain by using the nearest available lidar point data from the area surrounding each void. In some cases, the resulting interpolated surfaces may contain artifacts that misrepresent the elevation of the underlaying topography or bathymetry within the void extent. Any use of elevation data within void-interpolated areas should be treated with caution. The lidar elevation data are in U.S. survey feet. The spatial resolution (cell size) of the lidar-derived DEM is 1.5 ft. The spatial resolution of the orthoimagery is 0.5 ft. This data and metadata were submitted by California Department of Fish and Wildlife (CDFW) Staff though the Data Management Plan (DMP) framework with the id: DMP000723. For more information, please visit https://wildlife.ca.gov/Data/Sci-Data.