Woolpert Inc 20170331 Vector data Product: Breakline data is used to hydroflatten the DEMs created for the Mississippi NRCS FY16 Lidar project. Breaklines are reviewed against lidar intensity imagery to verify completeness of capture. The compilation procedure included use of lidar intensity, bare earth surface model, point cloud data, and open source imagery in an effort to manually compile hydrologic features in a 2-d environment. Following the compilation phase, a separate process was used to adjust the breakline data to best match the water level at the time of the lidar collection. Any ponds and/or lakes were adjusted to be at or just below the bank and to be at a constant elevation. Any streams were adjusted to be at or just below the bank and to be monotonic. Manual QAQC and peer-based QC review was performed on all delineated data to ensure horizontal placement quality and on all adjusted data to ensure vertical placement quality. Bridge breaklines were also compiled in efforts to generate an accurate DEM product. The final hydrologic and bridge breakline product was delivered in ESRI shapefile format and was also used in the processing of the DEM deliverable. Geographic Extent: AOI is located in Mississippi over Warren, Hinds, Claiborne, Jefferson, Adams, Franklin, Wilkinson, and Amite Counties. The area of interest covers approximately 4,780 square miles. Dataset Description: Mississippi NRCS FY16 Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.70 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83, Universal Transverse Mercator, meters and vertical datum of NAVD88 (GEOID12B), meters. Lidar data was delivered as flightline-extent unclassified LAS swaths, as processed Classified LAS 1.4 files, formatted to 5303 individual 1,500m x 1,500m tiles in NAD83(2011) UTM Zone 15N, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1,500m x 1,500m schema. Please note that tiles 15RXQ330320 and 15RXQ405950 do not contain lidar points. The data boundary intersects these tiles and a hydro breakline was digitized based on this boundary. For this reason a hydro-flattened DEM IMG and Intensity Image was generated. There will be no LAS 1.4 for tiles 15RXQ330320 and 15RXQ405950. The DEM IMG/Intensity tiff file count is 5903. The LAS 1.4 count is 5901. Ground Conditions: Initial collection of lidar data took place January and February of 2016. During this time some significant precipitation events occurred in the region and led to increased water levels in the Mississippi River and surrounding low-lying areas. Due to these high water levels it was determined that data acquisition be postponed until water levels lowered. Approximately 80% of the AOI had been acquired at this point. The remaining 20% was collected in January of 2017. Some water level differences will be observed in the point cloud and DEM data due to the differing collection dates, specifically in the low-lying areas near the Mississippi River. Woolpert has taken great care to limit the amount of temporal differences between the two collection dates. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Woolpert established a total of 103 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. Additional independent accuracy checkpoints were collected (120 NVA points and 90 VVA points) and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. Due to temporal variability, visible artifacts in the project DEM are evident within a historical floodplain along a portion of the Mississippi River. Lidar acquisition occurred when river levels were below action stage per NOAA flood gauge readings, however, some areas within the floodplain exhibited higher water levels during the January 2016 flights than what is observed in the January 2017 flights. This is specifically evident within oxbow streams and lakes found within the floodplain. Visible elevation variability in the DEM is located approximately within a bounding box of -91.36° East Longitude, 31.85° North Latitude; -91.24 West Longitude; 31.74 South Latitude. Data is used for: Soils Mapping, Wetlands delineation & management, Conservation Programs, 3-D Modeling Analysis, Engineering Design, Easements Planning, Dams, Hydrology & Hydraulics, Floodplain Analysis, Irrigation Systems, Precision Agriculture, Watershed Management, Erosion Control, Ponds, Cultural Resources, Water Resources, Ecology Determinations, and etc. USGS Contract No. G16PCO022, Task Order No. G16PD00331 CONTRACTOR: Woolpert Inc. 20160116 20170120 ground condition Complete As needed -91.654205 -90.049536 32.597549 30.962011 None Breaklines Model Lidar Elevation Data None United States Mississippi 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. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data. Data covers the entire area specified for this project. Breaklines were collected in all inland ponds and lakes ~2 acres or greater. These features were flat and level water bodies at a single elevation for each vertex along the bank. The entire water surface edge is at or below the immediate surrounding terrain. Breaklines were collected for all streams and rivers ~100' nominal width or wider. These features are flat and level bank to bank, gradient will follow the surrounding terrain and the water surface will be at or below the surrounding terrain. Streams/river channels will break at culvert locations however not at elevated bridge locations. All files are inspected to ensure that they conform to the specified file naming conventions, all files load in their correct geographic position, all files conform to the project specifications for file standard and content. Hydro Flattening Breakline Processing: Class 2 (ground) lidar points was used to create a bare earth surface model. The compilation procedure included use of lidar intensity, bare earth surface model, point cloud data, and open source imagery in an effort to compile hydrologic features in a 2-d environment. Elevation values were assigned to all inland Ponds and Lakes, Inland Pond and Lake Islands, Inland Stream and River Islands, using TerraModeler/LP360 functionality. All ground (Class 2) lidar data inside of the collected inland breaklines were then classified to water (Class 9) using TerraScan macro functionality. A buffer of 1.14 feet was also used around each hydro-flattened feature. These points were moved from ground (Class 2) to Ignored Ground (Class 10). Breaklines are reviewed against lidar intensity imagery and surface models to verify completeness of capture. The horizontal placement of breaklines is compared to terrain features and the breakline elevations are compared to lidar elevations to ensure all breaklines match the lidar within acceptable tolerances. Some deviation is expected between breakline and lidar elevations due to monotonicity, connectivity, and flattening rules that are enforced on the breaklines. Once completeness, horizontal placement, and vertical variance is reviewed, all breaklines are reviewed for topological consistency and data integrity using a combination of ESRI Data Reviewer tools. 20160116 Vector NAD 1983 2011 UTM Zone 15N 0.9996 -93.0 0.0 500000.0 0.0 coordinate pair 0.01 0.01 meters D NAD 1983 2011 GRS 1980 6378137.0 298.257222101 North American Vertical Datum of 1988 0.01 meters Explicit elevation coordinate included with horizontal coordinates 20170331 Woolpert Inc. mailing and physical

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