PART VII — WATER RESOURCES, FORESTRY, AND AGRICULTURE 



cause a definite reference surface is 

 not obvious. Nevertheless, the failure 

 of the Baldwin Hills Dam in western 

 Los Angeles, with the loss of many 

 lives and millions in property damage, 

 was probably due to withdrawal of 

 fluids from the underlying oil field. 

 The subsidence of many feet beneath 

 the city of Mexico was caused by 

 withdrawal of water from the lake 

 sediments on which the city was 

 built; considerable expenditures have 

 been needed to take care of drainage 

 disposal. 



Two other areas in California have 

 suffered large losses through with- 

 drawal of water from beneath. In the 

 Santa Clara Valley, pumping of water 

 from a confined aquifer at depth has 

 led to subsidence as great as 9 feet 

 between 1934 and 1959 in the city 

 of San Jose; subsidence has also 

 been considerable farther north in 

 the valley, including such important 

 industrial areas as Sunnyvale. 



On the west side of the San Joa- 

 quin Valley, dewatering of surficial 

 sediments had caused the surface 

 to subside as much as 23 feet by 

 1963 and forced alterations in the 

 plans for the new irrigation system 

 now under construction. 



Exhaustion of Groundwater 



Most of the agricultural produc- 

 tion of the High Plains of Texas and 

 eastern New Mexico tributary to the 

 cities of Lubbock, Amarillo, and Por- 

 tales depends on water pumped from 

 the Ogallala Formation, of Pliocene 

 age. The Ogallala is composed of 

 gravel and sand that was deposited 

 as a piedmont fan from the Rocky 

 Mountains to the northwest. Erosion 

 since its deposition has cut deeply 

 enough to sever the connection with 

 the mountain streams whose sedi- 

 ments led to the formation. The result 

 is that water pumped from the forma- 

 tion is not being recharged from 

 the mountains; the small amount of 

 recharge that feeds into the under- 

 ground reservoir is simply seepage 

 from the overlying arid surface. Es- 

 timates by the Texas Agricultural 

 Experiment Station were that re- 

 charge amounts to only about 104,000 

 to 346,000 acre feet of water for 

 the Texas portion of the High Plains, 

 whereas pumpage averaged 5 million 

 acre feet during the period from 

 1954 to 1961. Obviously, the water 

 table is sinking at a tremendous 

 rate, ranging from 1.34 to as much 

 as 3.72 feet per year, and the cost 

 of pumping is rising accordingly. 

 The water is being mined, just as 



literally as is coal from a coal seam, 

 and a drastic change in the economics 

 of the region is unavoidable. 



The Texas study projects the de- 

 cline in irrigated acreage from 3.5 

 million acres in 1966 to 125,000 acres 

 in 2015. Cotton production is ex- 

 pected to decline from about a million 

 bales in 1966 to 355,000 bales in 

 2015, of which 70 percent will be 

 grown on dry land. At 1966 prices, 

 the aggregate annual value of agricul- 

 tural production is projected to de- 

 cline 70 percent in fifty years. Drastic 

 economic change is clearly in sight, 

 not only for the farm operators but 

 for suppliers of farm machinery, auto- 

 mobiles, and other inputs into agri- 

 culture. Urban decline is also in- 

 evitable. 



Water is being mined at many 

 other places west of the 100th merid- 

 ian — notably in the Mojave Desert 

 of California and many of the inter- 

 montane valleys of the Basin and 

 Range Province in Arizona, Cali- 

 fornia, Nevada, Utah, and Oregon. 

 In each of these, results comparable 

 to the inevitable decline of the High 

 Plains are foreseeable, though the 

 rate of decline will vary from area 

 to area. 



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