Oregon Water Science Center
UPPER KLAMATH BASIN GROUND-WATER STUDYProblem Statement and Need for StudyThe demand for water in the upper Klamath Basin has increased in recent years. This increase is due, in part, to the growing demand for water for aquatic wildlife and other in-stream uses. These demands are in addition to the traditional uses of water for irrigation. Managing existing water supplies to fully satisfy all uses has proven difficult, particularly in dry years. Part of the solution may be to develop new sources of water. Ground water is likely be one such source. There is broad interest in exploring the use of ground water to alleviate water-supply problems in the basin. Ground water has historically been used to supplement surface-water for irrigation in dry years; this use is likely to increase. In addition to this traditional use, a number of other ground-water uses are being proposed. These include using ground water to augment or replace surface water for some uses, to augment stream flow, and to artificially recharge aquifers. Any large increases in ground-water pumping, however, are likely to be scrutinized for their potential to affect existing ground-water users and to affect streams. Assessing the effects of increased ground-water use requires a thorough understanding of the ground-water hydrology of the basin. The ground-water hydrology of the upper Klamath Basin, however, is understood in only a very general sense. No regional-scale quantitative studies have ever been undertaken. There is only limited information with which to evaluate the potential for new ground-water uses to affect existing ground-water users. In addition, there is only limited information with which to identify areas where ground-water development is unlikely to affect streams and areas where the potential for interference with streams might exist. The effects of climate on the ground-water system are also poorly understood. This lack of understanding could hinder efficient and prudent ground-water development, and potentially lead to additional problems. A thorough study to characterize and quantify the ground-water flow system in the basin is needed to address gaps in our present understanding. Such a study should include determination of the rates and distribution of ground-water recharge and discharge throughout the region, characterization of the geologic controls on ground-water flow, and identification of major hydrogeologic units. A study of this type should include development of a numerical flow model (computer model) to assess the conceptual understanding of the flow system and to provide a tool for estimating effects of developing new sources of water. Water-Resources Issues
Water Supply
There is an increasing demand for a limited supply of water in the Klamath Basin. The increasing demand is due not only to the economic growth of the region, but to the growing demands for water for aquatic wildlife and other in-stream uses.
In 1988 two species endemic to Upper Klamath Lake, the Lost River Sucker (Deltistes luxatus) and the shortnose sucker (Chasmistes brevirostris), were listed as endangered by the U.S. Fish and Wildlife Service. Changes in surface-water management necessary to protect these species have reduced the amount of surface-water available for diversion. Water supplies may be effected in the future by actions to mitigate the decline in populations of steelhead, coho, and Chinook salmon in the lower Klamath River. The coho has been listed as threatened by the National Marine Fisheries Service.
There are other instream water uses in addition to the needs of aquatic wildlife. Certain streams in both Oregon and California are designated as Wild and Scenic. In Oregon, scenic waterway flow rates have been adopted, and instream water rights have been issued to protect flow in some streams.
In addition to issues involving the absolute amount of water available, there are issues involving the conjunctive use of ground water and surface water. The nature and degree of the connection between ground water and surface water is an issue in certain areas of the Klamath Basin in Oregon. Concerns center around the potential for depletion of flow in streams and tributary springs by ground-water pumping. This issue will become more prominent as large-scale ground-water development is proposed to supplement or replace surface-water supplies.
Water Quality
Surface-water quality problems within the basin include elevated metals and nutrients concentrations, low dissolved oxygen, excessive turbidity, bacteria, and high stream temperatures. Identified nutrient sources include geologic materials and agriculture (Bortleson and Fretwell, 1993). High temperatures are often caused in part or made worse by low flows.
Klamath Lake has elevated nutrient concentrations and the historic record indicates that the lake has been eutrophic since the 1800's. The sources of nutrients to the lake have been a topic of study for several years. Wood and others (1996) studied the relation between selected water-quality constituents and lake stage, and Snyder and Morace (1997) studied nitrogen and phosphorous loading from drained wetlands adjacent to the lake. In the later study, it was shown that drained wetland (reclaimed) areas may contribute significant amounts of nitrogen and phosphorus to Upper Klamath Lake. In addition, flowing wells adjacent to the lake have high nitrogen (up to 8.7 mg/L) and phosphorus (up to 7.3 mg/L) concentrations suggesting that "total nutrient loading to Upper Klamath Lake from the discharge of ground water could be significant" (Snyder and Morace, 1997).
Ground-water quality problems exist also. Elevated fluoride and boron concentrations occur in ground water at some geothermal wells in the basin (Oregon State Water Resources Board, 1971).
Back to the Upper Klamath Basin Ground-Water Study page Contact: Marshall Gannett < mgannett@usgs.gov >
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