Water resources of the Satus Creek Basin, Yakima Indian Reservation, Washington

Abstract

The Satus Creek basin lies on the east flank of the Cascade Range in south-central Washington. The basin is entirely within the Yakima Indian Reservation and is bordered and drained on the east by the Yakima River. Average annual precipitation ranges from about 35 inches in the western upland to less than 10 inches in the eastern lowland. This amounts to a yearly total of about 562,000 acre-feet, most of which falls in the upland. Much of the precipitation falls as snow, and the streamflow from the upland reflects this fact, having a high sustained runoff during the snowmelt months of April, May, and June. In 1973 about 176,000 acre-feet of water was carried by canals for irrigation of about 19,000 acres in the lowland; of this quantity, about 173,000 acre-feet was imported from the adjoining Toppenish Creek basin. This high application rate of about 9.25 acre-feet of water per acre is largely responsible for severe waterlogging problems in many parts of the lowland. Also contributing to the problem are the fine-grained sedimentary deposits that generally overlie the alluvial sand and gravel aquifers in the lowland and retard downward percolation of applied water into those units. In other areas the upward discharge from aquifers in the underlying Yakima Basalt of the Columbia River Basalt Group contributes to waterlogging. Relieving artesiar heads by pumping, combined with reduced application and improved drainage, could alleviate the waterlogging, and free water for use in the irrigation of presently nonirrigated parts of the basin. Young volcanic rocks (basalt) in the southwestern, upland part of the basin appear to contain significant ground-water reservoirs. These rocks receive nearly 70,000 acre-feet a year in recharge from precipitation and, although much of this water is what sustains the high base flows of the streams draining the rocks, the remaining water offers potential for development as a high-altitude source for irrigation water.