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Federal
U.S. Level III and IV Ecoregions (U.S. EPA)
U.S. Environmental Protection Agency —
This map service displays Level III and Level IV Ecoregions of the United States and was created from ecoregion data obtained from the U.S. Environmental Protection... -
Federal
Changes in Stream Water Temperatures in the Chesapeake Bay Region, 1960-2014
U.S. Environmental Protection Agency —
This map shows the changes in stream water temperatures in the Chesapeake Bay region from 1960 to 2014. Blue circles represent cooling trends in stream water...