Use of water by bottom-land vegetation in lower Safford Valley, Arizona

Lower Safford Valley, Graham County, Ariz., is an alluvial lowland plain 1 to 3 measurements, and the rate of ground-water inflow to the bottom-land area was
determined on the basis of the hydraulic gradient, of the water table at. the time of each
set of seepage measurements, the transmissibility of the aquifer, and the length of the
reach. Although the methods differed greatly, the figure for use of ground water computed by each method was within 20 percent of the mean determined by averaging
the results of all six methods.
As a part of the investigation, the quality of the waters of lower Safford Valley was
studied in detail. The quality-of-water studies included more than 5,000 analyses of
surface and ground waters. These analyses showed that surface waters of the area
contain 250 to about 6,000 parts per million of dissolved solids and that ground waters
contain 200 to more than 10,000 parts per million. The waters of low dissolved-solids
concentration contain mostly sodium or calcium and bicarbonate. Highly mineralized
waters contain mostly sodium and chloride.
Based on the results obtained by the six methods, the total use of water by vegetation during the 12-month period ending September 30, 1944, was 28,000 acre-feet in a
total of 9,303 acres in the 46-mile reach of Gila River from Thatcher to Calva. As
precipitation and runoff were subnormal in most of the period of the investigation, it
is possible that the total use of water in other years may exceed 28,000 acre-feet. Of
the total water used, 23,000 acre-feet was derived frown the ground-water reservoir,
and the remainder was derived from precipitation on the area. Of the 23,000 acre-feet,
more than 75 percent was used by saltcedar.