Digital Layers

ESU boundaries were compiled by the GIS group at the Bonneville Power Administration from various sources based on written descriptions in NOAA Fisheries Service status reviews (available upon request) and mapping provided by the Fisheries Service. Initial boundaries were derived from USGS 1:250,000 scale hydrological unit boundaries. Boundaries were modified based on migration blockages and known fish distribution. Drainage basin delineation from blockages was based on 1:100,000 stream hydrography and/or available digital topography (1:250,000).

ESU polygons depict major basins within the current known range of each ESU. Species do not necessarily inhabit all drainages or river reaches depicted. More detailed information on species distribution within each ESU is available from NOAA and other federal, state and tribal resources.

Note that the Chinook and steelhead export files were updated on June 16, 2003, to reflect changes in the listing status/attributes of several ESUs. Please refer to the ESU Listing Status Snapshot (PDF 32KB) to confirm the ESA listing status of each species/ESU. Note also that some of the Chinook ESUs overlap with each other and require careful attention to the following overlap-related attribute fields: "esustatus2" "Name2" "esustatus3" and "Name3".

No liability is assumed for the accuracy or completeness of the ESU information.

Projection Information: 

*For those using ArcView:  If the layers fail to align properly, the false easting should be translated from meters into feet, making the false easting 2999901.82880.

For questions about the maps and geospatial files, contact Steve Stone, Northwest Region Portland Office; phone 503-231-2317.