The Environmental Sensitivity Index (ESI) maps and data are a compilation of shoreline, biological, and human use resources. The shoreline is classified by physical and biological characteristics and then ranked by its sensitivity to oiling. Biological resources are mapped hierarchically by element (such as bird, fish, invertebrate, and habitat), subelement (such as raptor, diadromous, bivalve, and coral) and species, and include attributes such as seasonality, threatened and endangered status, and concentration. Mapped human use resources include managed areas (such as state parks and preserves), historical sites, marinas, and beaches, among others.
- Area of Coverage: U.S. coastline, including Alaska, Hawaii, and American territories
- Dates Available: Varies by location
- Format: Varies based on location and age of the data. PDF available for all areas. GIS data available for most areas in a variety of formats, including Geodatabase, Shapefile, and ArcExport. GIS data also viewable in a free viewer.
- Resolution/Scale: 1:24,000, except in Alaska, where the scale is 1:63,000
- Minimal Mapping Unit: 50 meters
- Accuracy: Varies based on original source of shoreline
- Environmental Sensitivity Index (ESI) maps and data are updated as long as funding is available
- Recently updated areas:
- Florida – panhandle (November 2012)
- Florida – south (September 2013)
- Upper coast of Texas (September 2013)
- Updates in progress:
- Louisiana (expected completion March 2014)
- Delaware Bay (expected completion June 2014)
- Washington and Oregon outer coast (expected completion December 2014)
- Updates are also planned for the east coast from Maine to Georgia. All updates for that area should be completed by 2018.
Notes and Limitations: ESIs are developed in the context of oil spill planning and response. They are useful for many other applications, but users should recognize the limitations this context imposes. In particular, ESIs are not intended to be an inventory of biological resources, but they instead focus on species more susceptible or sensitive to oiling, areas of high concentrations, threatened and endangered species, and areas where sensitive life stages are found.