325 



were 1,626 marine terminal facilities providing deep water berths in 

 132 poits on the Atlantic, Gulf, and Pacific coasts. The significance of 

 these ports and terminal facilities is indicated by the 1965 statistics 

 which show that these ports handled 346,315,000 tons of foreign-trade 

 cargo which was 78 percent of the U.S. foreign trade total. In addi- 

 tion, the port facilities handled 332.1 million tons in coastal cargo and 

 288.2 million tons in local shipping. 



The estuarine ports also serve as essential elements of the national 

 defense system. The deep-water terminals exert a significant influence 

 on the location of defense installations as well as of the industrial com- 

 plexes necessary for logistical support of the defense effort. A direct 

 indication of the use of estuaries by naval vessels is the total number 

 of ships in commission. During the fiscal year 1967 this number was 

 931 with a planned increase to 960 in the fiscal year 1969. 



The use of the harbors for waterborne transportation is competitive 

 in that it may cause other uses to be forgone. Heavy ship traffic inter- 

 feres with pleasure boating and related activities (fig. IV.55). Mainte- 

 nance of the ship channels may alter the ecology and the surface area 

 occupied by the large vessels may well interfere with safe pleasure 

 boating. 



Water transportation is not the only type of transportation consid- 

 eration for estuaries. Since a major percentage of large cities are 

 located on estuarine systems, there is considerable pressure to develop 

 fill areas for airports which then utilize the long overwater approaches 

 to keep the jet noise away from developed areas. The water areas offer 

 a barrier to land travel that must be overcome with causeways or 

 bridge-type structures which can interfere with navigation or cause 

 habitat damage. On the other hand, peripheral roads offer some of the 

 more scenic routes available and are frequently the only undeveloped 

 area on which roads can be built. 



MUNICIPAL AND INDUSTRIAL WATER SUPPLY 



The water in the estuary can serve as a source of both domestic and 

 industrial water supply ; but utilization of estuarine water for domestic 

 supply is very limited at the present time. JSTormally the brackish water 

 is unpotable and treatment costs to render it potable lare extremely 

 high. The brackish estuarine water is also a poor source for mdustrial 

 process water. Here again a high degree of purity is normally required 

 in the process water and the cost of removing the dissolved salts is 

 prohibitive. 



Estuarine waters are used extensively, however, as a source of in- 

 dustrial cooling water. For this use the most important considerations 

 are the quantity and the ambient temperature. Water temperatures are 

 generally w^ell below the maximum for economical cooling, and since 

 the ocean is connected to one side of the estuary, the quantity is no 

 problem. Cooling water is required by both the manufacturing indus- 

 try and electric power generation plants; the greatest use is in the 

 thermal electric plants. 



The distribution of cooling water use parallels population and in- 

 dustrial development in the coastal counties, even though electrical 

 power can be transported economically over many miles. The greatest 

 concentrations of cooling water use are in the Middle Atlantic and 



