This polyline shapefile depicts ESI map data for the northern California shoreline. ESI data characterizes coastal environments and wildlife by their sensitivity to spilled oil. The ESI data includes information for three main components: shoreline habitats, sensitive biological resources and human-use resources.The Environmental Sensitivity Index (ESI) data were collected, mapped and digitized to provide environmental data for oil spill planning and response. The Clean Water Act with amendments by the Oil Pollution Act of 1990 requires response plans for immediate and effective protection of sensitive resources.