by 1975, such developments will be the chief 

 cause. 



—Increased volumes of pollutants such as pesti- 

 cides, lead oxide from automobile exhausts, and 

 other industrial and agricultural wastes, most of 

 which eventually end up in the Nation's coastal 

 zones. 



—Increased recreational demands, resulting in 

 more channel dredging for marinas, and small-boat 

 harbors, shoreline modification for beach stabiliza- 

 tion, and pollutants from recreational vessels. The 

 recreation industry is one of the fastest growing in 

 the Nation and the recreation needs are growing 

 much more rapidly than the population. 



—Increased dredging for larger and deeper ports 

 and harbors, with accompanying loads of spoil. 

 Dredging activities do not necessarily pose major 

 pollution problems, although all dredging increases 

 water turbidity and hence has some ecological 

 effects. However, the major pollution problem 

 with dredging is when the spoil itself is polluted. 

 Once it is stirred up or deposited in other water 

 areas, its effects are obviously spread. 



Lake Michigan currently is having problems 

 stenmiing from the deposit of polluted dredged 

 material. This was brought out during a conference 

 held in Chicago early in 1968 composed of 

 officials of the Federal Government and the four 

 States bordering on Lake Michigan. The officials 

 recognized that "the maintenance of waterways 

 for commercial and navigational use is a constantly 

 necessary activity." They concluded, however, 

 that "the continued deposition of dredged mate- 

 rial containing nutrients, oil, and soUds of sewage 

 and industrial wastes in Lake Michigan poses a 

 distinct threat to the quality of the lake." 



The Corps of Engineers agrees that wherever 

 practicable and as soon as practical dredge disposal 

 methods should be modified so that they will not 

 unreasonably accentuate the water pollution prob- 

 lem. 



—More and bigger nuclear-fired electric power 

 plants located on the shorelines in order to obtain 

 large quantities of cooling water. Electric power 

 production in this Nation has doubled during 

 every decade since World War II. Nuclear-fired 

 power plants, with their lower Rankine efficiency 

 and therefore higher unit heat loss than fossU- 



fueled power plants, are expected to supply 

 about half of the new generating capacity be- 

 tween now and 1975. It is estimated that, by 

 1980, the power industry will use one-fifth of 

 the total fresh water runoff of the United States 

 for cooling. 



The thermal effects of placing power plants 

 along an estuary or a coastline have yet to be fuUy 

 investigated. The temperature of the cooling water 

 leaving a power plant is about 1 5-25° higher than 

 when it enters. This thermal shock is lethal to a 

 variety of marine animals, particularly in their 

 larval stages. In addition, higher water tempera- 

 tures produce heavier growths of aquatic algae and 

 vegetation that are often undesirable. Such ecolog- 

 ical changes can prevent the production of game 

 fish and other species, resulting in their eventual 

 elimination. High temperatures may not only be 

 lethal but also may be a barrier to necessary 

 movement of migrant species offish. 



Figure 4. Although massive oil spills are dis- 

 astrous and must be controlled, a greater 

 problem exists in smaller chronic spills from 

 passing ships and loading piers, rendering 

 many beaches continually unfit for use. 

 (photo by Kirk Reid) 



—OH pollution and pollution from other hazardous 

 materials. Pollution of the marine environment 

 through massive oil spills has received increasing 

 public notice because of several recent dramatic 

 situations involving damaged tankers. These occur- 

 rences highhghted the ease with which natural 

 resources and the economic life dependent upon 

 them could be wiped out by one unfortunate 

 incident, and focused attention on the possibility 

 of other such incidences. Yet the most pervasive 

 pollution comes not from headlined oil spOls but 

 from the many activities that take place every day 

 underwater. There are about 16,000 oil wells off 



III-52 



