Quality of Waters From Playas on the Southern High Plains

Abstract

An estimated 2.5 to 3.0 million acre-feet of runoff water accumulate annually in playas on the Southern High Plains. This large water resource should be developed for more intensive use; however, past lack of knowledge about its quality has impeded progress. Thirteen playas were sampled over an area extending about 100 miles from northeast to southwest and covering two major soil types. The water from playas contained less salts than ground water and was of excellent quality for irrigation. Nitrate contents were less than 1.0 mg/1 in nearly all playas. Nitrogen fertilizer applied to farmland added little, if any, nitrate to the surface runoff water. Suspended solids contained in playa waters were high and variable but were substantially reduced by settling in deep reservoirs protected from wind and wave action.Water is the most limiting factor to crop production in the Southern High Plains. Irrigation from ground water has successfully removed the water limitation on several million acres of the area; however, the ground water is being mined, and there is little natural or artificial recharge occurring to replenish the supply. It is estimated that 2.5 to 3.0 million acrefeet of surface runoff water accumulate annually in the thousands of playas that dot the Southern High Plains. Most of this water is wasted by evaporation, but much of it could be conserved by storage in the aquifer. The region and its hydrology, plant water use, water conservation, geology, and related subjects have been discussed by Hauser [1966], Hauser and Signor [1967], Clyma [1964], Clyma and Lotspeich [1966], Cronin [1964], and Alexander [1961]. The quality of the runoff waters in playas must be known before substantial progress toward conserving these waters can be made. Suspended solids directly affect the feasibility of recharge by well injection. Dissolved salts determine the value of the water for irrigation and the possibility of unfavorable chemical reactions with the aquifer. Nitrates and other dissolved chemicals are potential health hazards if introx Now with Federal Water Pollution Control Administration, U.S.

Runoff and Reservoir Quality for Livestock Use in Southeastern Montana

“…Montana. However, long term gauging records and estimations Lotspeich et al (1969) found that runoff water in playas in from short term records indicate an average runoff of only 2.5 the Southern High Plains was less saline than ground water and cm per year in the area (Earl L. Neff, personal communication).…”