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Hydrology and quality of ground water in northern Thurston County, Washington

January 10, 1994

Northern Thurston County is underlain by as much as 1,000 feet of unconsolidated deposits of Pleistocene Age, that are of both glacial and nonglacial origin. Interpretation of 17 geologic sections led to the delineation of 7 major geohydrologic units, 3 of which constitute aquifers in the area. Precipitation ranges from about 35 to 65 inches per year across the study area. Estimates of gross recharge from precipitation indicate that the ground-water system of the area receives about 25 inches per year. The net recharge to the system (recharge from precipitation minus withdrawals from wells) is the equivalent of about 23 inches per year. Ground water generally moves toward marine bodies and to major surface drainage channels. Leakage from Lake St. Clair, which lies in a compound kettle within permeable glacial outwash, is almost 24 feet per year per unit area. Leakage from the lake may make up part of the water that discharges at McAllister Springs, north of the lake. Of the few water-quality problems encountered, the most widespread is seawater intrusion, which is caused by the activities of man. Most water-quality problems in the study area, however, are due to natural causes. Iron concentrations are as large as 21,000 micrograms per liter, manganese concentrations are as large as 3,400 micrograms per liter, and connate seawater is present in ground water in the southern pan of the study area.

Publication Year 1994
Title Hydrology and quality of ground water in northern Thurston County, Washington
DOI 10.3133/wri924109_1994
Authors N. P. Dion, G. L. Turney, M. A. Jones
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Water-Resources Investigations Report
Series Number 92-4109
Index ID wri924109_1994
Record Source USGS Publications Warehouse