EMAP's Estuaries Group assessed the status and trends in the condition of the nation's estuaries extending inland to the head of tide. In addition to coastal embayments, bays, inland water ways, and tidal rivers, the Estuaries Group also monitored coastal wetland areas and salt-water marshes. Monitoring and assessment activities were conducted jointly by the USEPA and the National Oceanic and Atmospheric Administration (NOAA).
The target populations for these resources were all of the Nation's estuarine waters (Figure Above). EMAP had adopted the same seven coastal regions, or biogeographical provinces used by the National Oceanic and Atmospheric Administration and the U.S. Fish and Wildlife Service.
EMAP's Estuaries Group developed the estuarine monitoring strategy cooperatively with the National Oceanic and Atmospheric Administration. EMAP had divided estuaries into the following classes: large estuaries, large tidal rivers, and small estuarine systems (including bays, inlets, and tidal creeks and rivers). Large estuaries, such as Chesapeake Bay, were sampled from an augmented EMAP grid, large tidal rivers, such as the Mississippi River, from systematic grids, and small estuarine systems from a list of all possible small estuarine systems.