11-10 



Characteristics of the Biophysical Regions 



North Atlantic Estuarine Region : Canadian border to Cape Cod. 



Cool, fertile waters with a large tidal range strike a steep, 

 indented coast with deep water close inshore, but protected 

 from the full force of the ocean waves by a wide continental 

 shelf. Moderate precipitation with heavy snowfall leads to 

 heavy spring river runoff which dominates local circulation. 

 Natural erosion and sedimentation are not severe problems, and 

 the evolution of drowned river valley estuaries is in an early 

 stage in this region. 



Middle Atlantic Estuarine Region : Cape Cod to Cape Hatteras, 

 exclusive of Chesapeake Bay. 



A wide, gently sloping continental shelf with a smooth shoreline 

 is cut by the entrances of several major river systems carrying 

 moderate amounts of sediments. The same cool, fertile waters 

 as in the North Atlantic estuarine region wash this coastline 

 but with a smaller tidal range. The evolution of drowned river 

 valleys into coastal marshes is in a secondary stage in the 

 larger estuarine systems, with sand spits and barrier islands 

 forming. 



