i17 Delta Levees Centerlines 2007

Detailed center lines of the Sacramento-San Joaquin levee systems, and broken into singular segments of consistent-attribute sets. This version created from mapping from the 2007 Delta LIDAR. The use of high-resolution LiDAR, and the products derived from it, allow for levee anatomy to be captured for the surveyed area. The resulting data allows for the levee crown sections to be isolated and collapsed to a centerline, detailing the route of the levee system. This data can further be used for levee maintenance and management, flood modeling and prediction, as well as levee inventories. The data are therefore mostly the structural center lines of the levees, with some minor modifications as warranted. In the Delta Anatomy Mapping Project, all levee anatomies were delineated using slope grids built from available 2007 Delta LIDAR data points. LIDAR data points were converted to digital elevation models and subsequently into slope grids. Thresholds were identified that capture the levee crown, levee landside, levee waterside, ramps and toe ditches. Visual interpretations of slope thresholds were used in conjunction with heads-up digitizing to maintain smooth boundaries at a scale of 1:550. The delineation thresholds were derived from a combination of mapping scale, slope grid resolution and slope thresholds used for each anatomy classification. All anatomy has gone through internal quality control processes to ensure a minimum accuracy of +/- 3 feet. Anatomy data was further reviewed and tested by DWR for compliance with an interpretive mapping standard of 80% accuracy.Once the levee anatomy was created and accepted, isolation and export of the levee crown was used in conjucture with ET Geowizards to collapse the crown to a singular centerline which details the levee route. This data depicts the levee anatomy at the time of the LiDAR survey (2007) and are only accurate for that time. Users should be aware that temporal changes may have occurred since this data set was created and some parts of this data may no longer represent actual surface conditions. Changes in some linework and attribution were performed by CA DWR Division of Engineering in September, 2018, and current version was posted to DWR GIS Atlas at that time. This data set was produced by joint effort of DWR and Chico State University. Data were originally developed and supplied by the Geographic Information Center at California State University at Chico, under contract to California Department of Water Resources. DWR subsequently modified the linework in a few places along with the attribution for various levee characteristics of interest. The associated data are considered DWR enterprise GIS data, which meet all appropriate requirements of the DWR Spatial Data Standards, specifically the DWR Spatial Data Standard version 3.1, dated September 11, 2019. DWR makes no warranties or guarantees — either expressed or implied — as to the completeness, accuracy, or correctness of the data. DWR neither accepts nor assumes liability arising from or for any incorrect, incomplete, or misleading subject data. Comments, problems, improvements, updates, or suggestions should be sent to GIS@water.ca.gov