323 



Nation's populaJtion, with a/bout four-fifths of it living in primarily- 

 urban areas which form about 10 percent of the total estuarinc zone 

 area. Another 13 percent of the estuarine land area is farmland, but 

 this accounts for only 4 percent of the total agricultural land of 

 the Nation. The estuarine zone, then, is nearly twice as densely popu- 

 lated as the rest of the country, and supports only one- fourth as much 

 agriculture per unit area. 



In those regions lying between Cape Hatteras, N.C., and Canada as 

 well as in the Pacific Southwest, over 90 percent of the population 

 lives in urban areas ; over much of the Atlantic estuarine zone stretches 

 the great northeastern megalopolis with population densities averag- 

 ing over 1,000 persons per square mile. The remainder of the estuarine 

 zone of the United States exhibits a pattern of major centers of popu- 

 lation clustered around natural har^bors and separated by stretches of 

 coastline which are either empty and inaccessible or beginning to be 

 sprinkled with private residences and resort communities in the vicini- 

 ties of population centers. 



The coastal counties have within their borders 40 percent of all man- 

 ufacturing plants in the United States. The mixture of manufacturing 

 types in the estuarine zone is the same as the national composition with 

 only minor execptions, such as the concentration of the apparel manu- 

 facturing industry in the Middle Atlantic region, particularly in the 

 New York area. Distribution of manufacturing types among the bio- 

 physical regions shows regional differences related to historical devd- 

 opment as well as raw material and market availability. 



Over half of all plants in the coastal counties and one-fifth of all 

 manufacturing plants in the United States are located in the Middle 

 Atlantic biophysical region, which was the historical center of the 

 Nation's industrial growth and is still one of the major market areas. 

 The Pacific Southwest is the major industrial center of the Pacific 

 coast and is developed as intensively as the Middle Atlantic region. 

 Some industrial development in other regions tends to follow histori- 

 cal or present raw material availability. Leather product plants are 

 clustered in the North Atlantic region, and lumber manufacturing 

 plants are most plentiful in the Pacific Northwest. Food processing 

 plants, however, follow closely the distribution of population. 



While much of the industrial development located in coastal coun- 

 ties affects the estuarine zone indirectly through use of adjacent land, 

 some of the water-using industries have an impact on the estuarine 

 zone far beyond their numbers. The paper, chemical, petroleum, and 

 primary metals industries are the major water users among manu- 

 facturing establishments and are distributed universally throughout 

 the estuarine zone. 



USE or THE ESTUARINE ZONE 



Many of the uses cataloged in this report occur only because the 

 historical growth of the country makes the estuarine zone the place 

 where the people and the industry are. Only commercial navigation 

 and commercial fishing are uses which are primarily associated with 

 the estuarine zone rather than other parts of man's environment. Uses 

 such as water supply, waste disposal, and recreation are associated 

 with civilization wherever it exists ; in the estuarine zone they may have 

 different values, different emphasis, or different impact on the bio- 

 physical environment. 



