Description: This layer is a polygon file containing CMECS Aquatic Setting classes for the Columbia River estuary. The CMECS Aquatic Setting classification distinguishes oceans, estuaries and lakes, deep and shallow waters and submerged and intertidal environments within which more refined classification of geological, physicochemical, and biological information can be organized. It is comprised of three hierarchical levels (System, Subsystem and Tidal Zone) and provides the context for all CMECS components. We used methods developed in Oregon to classify estuaries using CMECS. Detailed information on the Oregon methods can be found here: http://www.coastalatlas.net/documents/cmecs/EPSM_CoreGISMethods.pdf