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of the shoreline and water in the period of maximum vegetal growth, 

 and often the time when supplies of fresh water for all purposes such 

 as drinking, carrying municipal wastes, et cetera, are least available. 

 Instructive in this regard is the growth of resort communities, such 

 as Ocean City, Md., from sleepy towns of 25,000 persons in April, to 

 "cities" of 350,000 on weekends in the summer months. 



Perhaps the greatest recent change in user group pressure results 

 from the tremendous growth of permanent residences constructed in 

 coastal and estuarine locations. Recreation amenities provided by these 

 areas is a prime factor in this trend. Although growth figures are not 

 uniformly available, the growth of permanent and "second" homes 

 appears to be general throughout the Nation, particularly in out- 

 lying "suburbs" tied to metropolitan job centers by expanding trans- 

 portation networks. This growth of permanent users of the estuarine 

 zone is further increased by the phenomenal expansion of retire- 

 ment communities in such areas as Florida, Texas, and California. 



Figure IV.4.17 summarizes the projections of leisure time which 

 contribute heavily to the pressures discussed above. 



Section 4. Future Waste Discharge Impacts 



The amounts and impact of wastes generated by man's activities 

 are a function of population growth, urbanization, industrial and 

 commercial development, changing technologies, and consumption of 

 goods and services — even those associated with leisure-time activities. 

 The following discussion defines trends and the probable future course 

 of events related to waste discharge affecting the estuarine zone. How- 

 ever, in most cases, only an indication of the magnitude of the prob- 

 lem can be set out here due to the lack of comparable long-term data, 

 the complexity of the waste discharge assimilation process, and the 

 unknown quantity and composition of future waste discharges. 



The emphasis in the following discussion is on those trends in 

 waste discharge that most directly affect water quality, although it 

 must be recognized that the problems associated with wastes affect the 

 total environment, and extend well beyond the defined area of the 

 estuarine zone, both landward and seaward. 



LIQUID wastes 



Fresh loater inflows 



Many of the sources that determine estuarine water quality are and 

 will be external to the estuarine zone. The quantity, as well as quality, 

 of fresh water inflows to the estuaries is largely determined by up- 

 stream water use. Water diversion for irrigation, impoundment for 

 flood control, and a host of other uses tend to cut the natural stream- 

 flow necessary to the successful assimilation and diffusion of both natu- 

 ral and manmade wastes. An example of upstream diversion of water is 

 provided by the Texas Water Plan, which is projected to alter stream- 

 flows radically into such productive estuaries as Galveston Bay and 

 those situated in the southern Texas coast. Even if a tremendous 

 planned diversion from the Mississippi River for fresh water inflows 

 to the estuaries is completed on a timely basis, these estuarine systems 

 are projected to face overall reduction of fresh water supply and the 



