Estuarine Drainage Area. "An Estuarine Drainage Area is that component of an estuary's entire watershed that empties directly into the estuary and is affected by tides. EDAs may be composed of a portion of a single hydrologic unit, an entire hydrologic unit, more than one hydrologic unit, or several complete hydrologic units and portions or several adjacent hydrologic units."Every EDA has both a land and water component, with the land component comprised of a mainland component and, for certain EDAs, an island component. Overall size and characteristics of these EDAs varies greatly. For example the Chesapeake Bay EDA including its subEDAs along the Mid-Atlantic coast covers 38,200 square miles while several EDAs or subEDAs along the Pacific coast cover 100 square miles or less." This information was taken from the NOAA ORCA CAF Web page.