Summary appraisals of the nation's ground-water resources – Pacific Northwest region

Abstract

The Pacific Northwest Region's groundwater reservoirs are capable of providing large additional freshwater supplies; these reservoirs become more important as undeveloped surface-storage sites and unapportioned surface-water supplies dwindle. Withdrawals of fresh water from all surface and underground sources are increasing; they may rise from the rate of 30 billion gallons per day in 1970 to about 60 billion gallons per day in 2020. By 1975 the withdrawal of ground water had increased 70 percent over the 1970 rate and accounted for 22 percent of total freshwater withdrawal. Substantial increases in groundwater withdrawal must continue if projected water demands are to be met in the future. Large variations exist in the availability of and needs for ground water in the region, largely because of the great variety oflandforms, climate, and earth materials. More than one-half the region is underlain by rock materials capable of yielding ground water to wells at moderate to large rates; six extensive areas are identified as major groundwater reservoirs. The most significant current problems pertaining to one or more ofthese groundwater reservoirs are: (1) Progressively declining water levels; (2) water-quality problems; (3 l waterlogging; (4) inadequate information; and (5) competition for available supplies. In the future these same problems are expected to persist and generally worsen (especially water-quality deterioration) in most of the major reservoir areas. Management opportunities in the region include: (1) Development of new supplies and additional uses of ground water; (2) protection and enhancement of water quality; (3) reduction of waterlogging; (4) energy development from some groundwater reservoirs; (5) improving access to the ground water; (6) increased use of underground space for storage and disposal; and (7) greater use of advanced management and conservation techniques. Conjunctive use of surface and ground water to provide greater available supplies probably is the most promising water-management opportunity. However, if the full potential of the groundwater resources is to be realized, important constraints, including present water-right structures and serious deficiencies in information, must be overcome.

Water-quality assessment of the Puget Sound basin, Washington: Environmental setting and its implications for water quality and aquatic biota

“…Dissolved iron and manganese are two natural constituents of concern in the ground water of the Puget Sound Basin (Foxworthy, 1979;Turney, 1986;and Embrey, 1988). Water from 186 of 1,376 wells (14 percent) in the study unit exceeded the dissolved iron secondary MCL for drinking water of 500 |LLg/L (micrograms per liter) (U.S. Environmental Protection Agency, 1992b).…”

“…Water from 186 of 1,376 wells (14 percent) in the study unit exceeded the dissolved iron secondary MCL for drinking water of 500 |LLg/L (micrograms per liter) (U.S. Environmental Protection Agency, 1992b). Some type of treatment to remove or reduce the effects of dissolved iron is a common practice when ground-water supplies are developed in the region (Foxworthy, 1979). Although dissolved iron and manganese concentrations commonly exceed standards, other minor and trace elements rarely do, according to Turney (1986), who sampled more than 100 wells and springs in the Puget Sound region.…”

“…Known and suspected occurrences of ground-water contamination from sources at the land surface are numerous. The sources of ground-water contamination differ widely and include solid-waste landfills, spilled chemicals and petroleum fuels, wastes from mining and milling operations, waste-treatment lagoons, feedlots, large wood-waste disposal sites, and fertilizer and pesticide applications (Foxworthy, 1979;and U.S. Environmental Protection Agency, 1987). To mitigate sources of contamination of ground waters, Washington State agencies have worked since 1987 to develop ground-water-quality standards, regulate underground storage tanks, revise well construction standards, and develop solid and hazardous waste-management programs (Stratton, 1992).…”

Relationship of regional water quality to aquifer thermal energy storage

“…High concentrations of sodium chloride in deep ground water are often traceable to solution of halite earlier precipitated within marine sediments (Foxworthy 1979). This effect is common in the lower Mississippi region .…”

Plan of study for the regional aquifer-system analysis of the Snake River plain, Idaho and eastern Oregon

“…The study area is included in a summary appraisal-of groundwater resources in the Pacific Northwest region by Foxworthy (1979) The eastern part, which comprises two-thirds of the plain, is underlain by the Snake Plain aquifer (Mundorff and others, 1964, p. 142), a thick (several thousand feet) sequence of basalts of Quaternary age that constitutes a major source of water in Idaho. Discharge of the Snake Plain aquifer is largely from a unique set of springs concentrated along a 50-mi reach of the Snake River between Twin Falls and Bliss.…”