132 



MUNICIPAL AND INDUSTRIAL WATER SUPPLY 



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

 industrial water supply, but its utilization for domestic supply is very 

 limited at the present time. Normally the brackish water is unpotable 

 and treatment costs to render it potable are extremely high ; however, 

 where the upstream freshwater inflow is sufficient to repel salinity 

 intrusion from portions of the tidal area, the water is used for a domes- 

 tic and agricultural water supply source. The San Francisco Bay 

 Delta area is an excellent example of this, although there are a few 

 others. 



The brackish estuarine water is also a poor source for industrial 

 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 indus- 

 trial cooling water. For this use the most important considerations are 

 ambient temperature and quantity. Water temperatures are generally 

 well 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 industry and elec- 

 tric power generation plants ; the greatest use is in the thermal electric 

 plants. Table IV.2.7 shows cooling water withdrawals in the coastal 

 counties. Not all of the amounts shown are taken from estuarine waters, 

 but almost all of these quantities find their way back into estuarine 

 waters. 



The distribution of cooling water uses 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 Pa- 

 cific Southwest regions; these regions both have moderate water 

 temperatures which make possible efficient use of the available cooling 

 water. 



Table IV.2.7 also shows, however, that there are 47 nuclear power- 

 plants built or scheduled for completion by 1976. All of these are in the 



TABLE IV.2.7.— ESTIMATED COOLING WATER USE IN THE COASTAL COUNTIES. 1963 

 [Water use in million gallons per day] 



Existing or 



planned 



Power Manufactur- nuclear 



Total cooling generating ing industrial powerplants 



Biophysical region water use plant use use (number) 



North Atlantic 1,480 1,200 280 3 



Middle Atlantic .-. 11,030 9,000 2,030 20 



Chesapeake Bay 1,040 850 190 5 



South Atlantic 350 290 60 8 



Caribbean 330 270 60 3 



Gulf ot Mexico 1,020 830 190 1 



Pacific Southwest 3,850 3,150 700 5 



Pacific Northwest 900 730 170 2 



Alaska.. _ (0 (0 (') 0) 



Pacific Islands 100 80 20 (') 



Total, estuarine zone 20,100 16,400 3,700 



1 No data. 



Reference: National Estuarine Inventory. 



Data source: U.S. Department of Commerce, Bureau of the Census, Census of Manufactures 1963. 



