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Ground Water Atlas of the United States - Segment 1 California Nevada


Fresh Ground-Water Withdrawals

Significant ground-water use in the Santa Clara Valley began about 1900 with the development of irrigated agriculture. Average annual agricultural withdrawals increased from about 40,000 acre-feet per year from 1915 to 1920 to a maximum 5-year average of about 103,000 acre-feet per year from 1945 to 1950. After 1945, urban and industrial development increased rapidly, and irrigated acreage began to decline; agricultural withdrawals decreased to an average 20,000 acre-feet per year from 1970 to 1975. Meanwhile, municipal and industrial withdrawals increased from about an average of 22,000 acre-feet per year from 1940 to 1945 to an average of 131,000 acre-feet per year from 1970 to 1975. Total withdrawals in the valley increased from 50,000 acre-feet per year from 1915 to 1920 to 185,000 acre-feet per year from 1960 to 1965, and then declined to about 150,000 acre-feet per year from 1970 to 1975 when surface-water imports increased sufficiently to offset the excessive ground-water withdrawals.

Municipal and industrial ground-water use began to exceed agricultural use early in the 1960's. Currently (1995), municipalities and industries account for about 90 percent of the water used in the valley. Ground water used for irrigated agriculture averaged about 14,000 acre-feet per year from 1975 to 1980, while the amount withdrawn for municipal and industrial use was about 150,000 acre feet per year. The combined annual agricultural, municipal, and industrial ground-water withdrawals of about 164,000 acre-feet were about one-half of the total water used in the valley.


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