This polygon shapefile depicts the distribution of extant vernal pool complexes in Placer Country for use by the United States Fish and Wildlife Service in recovery planning for listed and sensitive species. True color aerial slides from the Deptartment of Water Resources were interpreted, and vernal pool complexes were identified. Complexes more than 40 acres in size were then digitized as polygons and given a density rating (see Resource Fields for attribute definitions). This layer was created to help biologists and resource planners make informed decisions in their recovery and planning efforts. It depicts vernal pool complexes, not individual vernal pools. Since the minimum mapping unit of the coverage is 40 acres, it may not provide the level of detail required for larger scale (smaller area, more site-specific) conservation planning. This coverage was produced based on 1999 aerial photography, supplemented by experience with numerous delineation and inventory projects throughout the vernal pool areas of Placer County. Pre-existing vernal pool delineations served as an additional reference source. Additional documentation is provided with the data. This coverage is a polygon layer of vernal pool complexes in Placer County. In 1995, Dr. Robert F. Holland identified the complexes on aerial photos (the most recent available for each county) and traced the polygons onto USGS 7.5' quads from which they were digitized. Vernal pool complexes were then given a density rating. The coverage was refined in June of 1998, with SPOT Imagery and recent U2 (low-flying aircraft) photography. The layer does not contain delineations of individual vernal pools and was not intended for use in wetland delineations. This coverage allows for assessment of vernal pool areas for Placer County, California. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
