Agricultural losses involving the quality of ground water arise 
principally in areas where overpumping has depressed the water 
table to the point where the supply has become contaminated by 
saline ground water, particularly sea water. In limited areas 
agricultural water supplies have become contaminated by brine 
from oil wells and by other industrial wastes. Where saline 
water has reached canals or pipes that supply irrigation or 
stock water wells, the operators must either reduce or cease 
pumping or install expensive recharge systems. 
Whereas losses of irrigation water are limited largely to the 
irrigated arsas of the arid West, losses from overdraft of 
ground water and encroachment of sea water also reach local in-~ 
portance in many humid areas. The comparatively humid State of 
Louisiana, for example, with heavy pumping for rice irrigation, 
has had more cases of failing ground-water supplies than has 
Nevada with the lowest precipitation and runoff of any State. 
Similarly, Florida, with 60 inches of annual rainfall, has had 
seriously depleted ground-water reserves, with the result that 
sea water has reached wells as far as 8 miles inland. In Florida, 
as in Louisiana, these losses are only partly agricultural. 
Other areas where ground-water depletion and saline encroachment 
are particular problems for both urban and agricultural use ine 
clude Santa Ana, California, southern Arizona, southern Alabama, 
the southern high plains of Texas, and irrigated valleys such 
as the Rio Grande of Texas and New Mexico and the Central Valley 
of California. 
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