NV5 Geospatial 20230413 Vector Digital Data Product: Hydroflattened breaklines covering the CA North Sierra 2 2022 project area. Geographic Extent: This dataset and derived products encompass an area covering approximately 1,079,690 acres of Sierra Nevada Northern region. Dataset Description: Dataset Description: Lidar flight line swaths were processed to create 4,425 classified LAS 1.4 files delineated in 1,000m x 1,000m tiles. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Water's Edge breaklines were developed using an algorithm which weights lidar-derived slopes, intensities, and return densities to detect the water's edge. The water's edge was then manually reviewed and edited as necessary. Lakes were assigned a consistent elevation for an entire polygon while rivers were assigned consistent elevations on opposing banks and smoothed to ensure downstream flow through the entire river channel. Flattened water features include all rivers exceeding 30 meters in nominal width and lake features exceeding 2 acres in total area as well as smaller features as feasible. Bridge breaklines were additionally developed and used to enforce elevations beneath bridges in the absence of ground and to prevent saddling in the hydroflattened bare earth digital elevation models. Additional products include classified LAS files, intensity images, Hydroflattened DEMs, and highest hit surface models. Ground Conditions: Acquisition occurred free of smoke, fog and cloud cover. The purpose of the lidar data was to produce a high accuracy 3D dataset that meets all necessary standards laid out by the 3D Elevation Program and the CA North Sierra 2 2022 contract. The lidar point cloud data were used to create classified lidar LAS files, intensity images, hydro-flattened DEMs, highest hit surface models, and 3D breaklines of rivers and lakes within the study area. USGS Contract No. 140G0221D0012 CONTRACTOR:NV5 Geospatial. Ground Control Points were acquired and calibrated by NV5 Geospatial. Data acquisition was coordinated by NV5 Geospatial and all lidar data calibration, and follow-on processing were completed by NV5 Geospatial. Breakline File Type = Shapefile Breakline Elevation Units = Meters Downhill Treatment Applied = Monotonic Type of Hydro Treatment Required = Hydro-flattened 20211116 20211201 ground condition In work As needed -121.437338 -120.380923 39.270645 38.486708 636255.333800 726000.000000 4263000.000000 4348000.000000 none breakline remote sensing Elevation data Lidar Hydrology none California No restrictions apply to these data. None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgment of the U.S. Geological Survey would be appreciated for products derived from these data. Breaklines were manually reviewed to ensure the capture of all lakes > 2 acres and rivers with a nominal width > 30m. Breaklines are complete for the entire project area. Lidar Pre-Processing: 1. Review flight lines and data to ensure complete coverage of the study area and positional accuracy of the laser points. 2. Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. 3. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey. 4. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las format. Convert data to orthometric elevations by applying a Geoid 18 correction. 5. Apply refraction correct to bathymetric returns by flightline. 6. Import raw laser points into manageable blocks to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines. 7. Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration. 8. Adjust the point cloud by comparing ground classified points to supplemental ground control points. CA North Sierra 2 2022 Ground Control 20230413 Lidar Post-Processing: 1. Classify data to ground and other client designated classifications using proprietary classification algorithms. 2. Manually QC data classification 3. After completion of classification and final QC approval, calculate final NVA and VVA values for the project using ground control quality check points. Final density information will also be calculated. 20230413 Hydro-flattening Breaklines and Hydro-flattened DEM creation: Water boundary polygons were developed using an algorithm which weights lidar-derived slopes, intensities, and return densities to detect the water's edge. The water's edge was then manually reviewed and edited as necessary. Elevations were assigned to the water’s edge through neighborhood statistics identifying the lowest lidar return from the water surface. Lakes were assigned a consistent elevation for an entire polygon while rivers were assigned consistent elevations on opposing banks and smoothed to ensure downstream flow through the entire river channel. These breaklines were incorporated into the hydro-flattened DEM by enforcing triangle edges (adjacent to the breakline) to the elevation values derived from the breakline. This implementation corrected interpolation along the hard edge. Breaklines were also used to classify all ground points within the identified water bodies to class 9 (water). 20230413 Vector Universal Transverse Mercator 10 0.9996 -123.0 0.0 500000.0 0.0 coordinate pair 0.001 0.001 Meters North American Datum of 1983 2011 GRS_1980 6378137.0 298.257222101 North American Vertical Datum of 1988 Geoid 18 0.01 Meters Explicit elevation coordinate included with horizontal coordinates 20230413 20230413 NV5 Geospatial mailing and physical

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Corvallis OR 97330 USA 541-752-1204 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 None None None Unclassified None None None