Artesian-water levels and interference between artesian wells in the vicinity of Lehi, Utah

Abstract

In the vicinity of Lehi, Utah, about 25 miles south of Salt Lake City, supplies of artesian water are obtained at depths of 75 to 750 feet from beds of sand and gravel of Pleistocene age. Individual beds are probably lenticular and irregular in shape, as is characteristic of the stream and lake deposits in many parts of the Lake Bonneville Basin. The artesian supplies are obtained from aquifers or groups of aquifers that are more thoroughly separated by impermeable materials than the artesian aquifers of some other ground-water areas in Utah. Most of the wells are between 130 and 200 feet deep. The artesian area in the vicinity of Lehi is only a small part of a ground-water unit that probably includes most of Utah Lake Valley. The ground-water reservoir in Utah Lake Valley was seriously depleted after the years of subnormal precipitation that culminated in the drought of 1934. However, in the vicinity of Lehi the static levels in 1934 were about the same as during 1904, a year which marked the culmination of a previous drought period. The water levels in the summer of 1935 were about the same as in 1934, indicating that the recharge to the ground-water reservoir was again sufficient to balance the discharge; and during the following year there was a marked rise of the water level in all wells, commonly 5 to 10 feet in amount. The static levels in the vicinity of Lehi fluctuate each year through a range of as much as 15 feet and are ordinarily highest during March or April and lowest during August or September. This fluctuation is due in part to the closing of flowing irrigation wells during the winter. A series of tests was made to determine the extent of interference between artesian wells. Among the wells that are between 130 and 200 feet deep, the operation of certain wells was found to cause a change in the static level in wells as much as 1 1/5 miles distant. The operation of these shallower wells, however, had no apparent effect upon the static level in the wells more than about 200 feet deep nor did the operation of these deeper wells appear to affect the static level in the shallow wells. The deep and shallow aquifers thus appear to be separated by fairly continuous beds of impermeable material.