Oregon Water Resources Department
Browse All Documents
1–3 of 3
Geohydrology and Numerical Model Analysis of Ground-Water Flow in the Goose Lake Basin, Oregon and California$0.00
Geohydrology and Numerical Model Analysis of Ground-Water Flow in the Goose Lake Basin, Oregon and CaliforniaU.S. Geological Survey, Oregon Water Resources Department | December 15, 1988...Summary
From the early 1970s until 1981, ground-water development in the Goose Lake basin underwent rapid growth. The number of new wells constructed and...
From the early 1970s until 1981, ground-water development in the Goose Lake basin underwent rapid growth. The number of new wells constructed and total State-permitted ground-water withdrawals for irrigation reflect the increase in ground-water development that occurred during this period.
A strong agricultural economy spurred much of the development by providing incentives to expand irrigated acreage and modernize irrigation methods (from gravity to sprinkler systems). The drought of 1976-77 also encouraged farmers to develop ground water as a supplemental source to less reliable surface-water supplies used in the past.
A preliminary assessment of the basin by OWRD staff (R. B. Almy, Oregon Department of Water Resources, written commun., 1981) concluded that, based on rates of water-level decline and increases in withdrawals, further and more detailed study of the basin was warranted. Between 1975 and 1982, water-level declines in some OWRD observation wells ranged from 0.5 to 3 feet per year, while permitted ground- water withdrawals increased at an average rate of 4,000acre-feetperyear(acre-ft/yr). Similarwater-level declines and increases in withdrawals occurred near Davis Creek on the California side of the basin during this period. This prompted a 1982 assessment of ground-water conditions by the California Department of Water Resources (California Department of Water Resources, 1982).
At the time of OWRD's assessment it was felt that too little information on the actual rates of ground-water use, recharge, and the geohydrology of the aquifer system was available to allow proper managementoftheresource. If the rates of water-level decline and ground-water withdrawal that existed prior to 1981 had continued, issuance of new permits for ground-water use potentially could have been halted in order to determine if the Goose Lake basin should be designated as a "criticalground-water area." Sucha designation would allow the State of Oregon to limit the use of ground-water resources in the area.
However, overdraft of the ground-water resource became a less urgent issue after 1982, when a downturn in the agricultural economy, combined with rising costs of electrical power (and thus pumping), resulted in a widespread reversion to dryland farming and low-water-use crops.
Adverse agricultural market conditions halted the growth of ground-water development in the basin; these trends could conceivably reverse in the future to spur growth again. In recognition of this potential and the need to build an understanding of the basin in order to properly manage future ground-water development, OWRD entered into a joint program of study with the U.S.GeologicalSurvey. The first of a proposed series of ground-water basin assessments, this 1-year study was started in 1986 with the goals of characterizing the nature, extent, and properties of water-bearing rocks within the basin and describing and quantifying the components of recharge to, and discharge from, the basin.
Additionally, this study was designed toe valuate the adequacy of available and readily collectable information to quantitatively describe the geohydrology of the basin. If this information was found to be inadequate, the study would also identify the data needed to better describe, understand, and manage the ground-water resource.
Ground-Water Hydrology of the Upper Klamath Basin, Oregon and California$0.00
Ground-Water Hydrology of the Upper Klamath Basin, Oregon and CaliforniaU.S. Geological Survey, Oregon Water Resources Department | April 15, 2010...Summary
The upper Klamath Basin spans the California-Oregon border from the flank of the Cascade Range eastward to the Basin and Range Province, and...
The upper Klamath Basin spans the California-Oregon border from the flank of the Cascade Range eastward to the Basin and Range Province, and encompasses the Klamath River drainage basin above Iron Gate Dam. Most of the basin is semiarid, but the Cascade Range and uplands in the interior and eastern parts of the basin receive on average more than 30 inches of precipitation per year. The basin has several perennial streams with mean annual discharges of hundreds of cubic feet per second, and the Klamath River at Iron Gate Dam, which represents drainage from the entire upper basin, has a mean annual discharge of about 2,100 cubic feet per second. The basin once contained three large lakes: Upper and Lower Klamath Lakes and Tule Lake, each of which covered areas of 100 to 150 square miles, including extensive marginal wetlands. Lower Klamath Lake and Tule Lake have been mostly drained, and the former lake beds are now cultivated. Upper Klamath Lake remains, and is an important source of irrigation water. Much of the wetland surrounding Upper Klamath Lake has been diked and drained, although efforts are underway to restore large areas. Upper Klamath Lake and the remaining parts of Lower Klamath and Tule Lakes provide important wildlife habitat, and parts of each are included in the Klamath Basin National Wildlife Refuges Complex.
The upper Klamath Basin has a substantial regional ground-water flow system. The late Tertiary to Quaternary volcanic rocks that underlie the region are generally permeable, with transmissivity estimates ranging from 1,000 to 100,000 feet squared per day, and compose a system of variously interconnected aquifers. Interbedded with the volcanic rocks are late Tertiary sedimentary rocks composed primarily of fine-grained lake sediments and basin-filling deposits. These sedimentary deposits have generally low permeability, are not good aquifers, and probably restrict ground-water movement in some areas. The regional ground-water system is underlain and bounded on the east and west by older Tertiary volcanic and sedimentary rocks that have generally low permeability. Eight regional-scale hydrogeologic units are defined in the upper Klamath Basin on the basis of surficial geology and subsurface data.
Ground water flows from recharge areas in the Cascade Range and upland areas in the basin interior and eastern margins toward stream valleys and interior subbasins. Ground water discharges to streams throughout the basin, and most streams have some component of ground water (baseflow). Some streams, however, are predominantly ground-water fed and have relatively constant flows throughout the year. Large amounts of ground water discharge in the Wood River subbasin, the lower Williamson River area, and along the margin of the Cascade Range. Much of the inflow to Upper Klamath Lake can be attributed to ground-water discharge to streams and major spring complexes within a dozen or so miles from the lake. This large component of ground water buffers the lake somewhat from climate cycles.
There are also ground-water discharge areas in the eastern parts of the basin, for example in the upper Williamson and Sprague River subbasins and in the Lost River subbasin at Bonanza Springs.
Irrigated agriculture is an integral part of the economy of the upper Klamath Basin. Although estimates vary somewhat, roughly 500,000 acres are irrigated in the upper Klamath Basin, about 190,000 acres of which are part of the Bureau of Reclamation Klamath Project. Most of this land is irrigated with surface water. Ground water has been used for many decades to irrigate areas where surface water is not available, for example outside of irrigation districts and stream valleys. Ground water has also been used as a supplemental source of water in areas where surface water supplies are limited and during droughts. Ground water use for irrigation has increased in recent years due to drought and shifts in surface-water allocation from irrigation to instream uses. The shifts in surface-water allocation have resulted from efforts to improve habitat for fish listed under the Federal Endangered Species Act.
The ground-water system in the upper Klamath Basin responds to external stresses such as climate cycles, pumping, lake stage variations, and canal operation. This response is manifest as fluctuations in hydraulic head (as represented by fluctuations in the water-table surface) and variations in ground-water discharge to springs. Basinwide, decadal-scale climate cycles are the largest factor controlling head and discharge fluctuations. Climate-driven water-table fluctuations of more than 12 feet have been observed near the Range, and decadal-scale fluctuations of 5 feet are common throughout the basin. Ground-water discharge to springs and streams varies basinwide in response to decadal-scale climate cycles. The response of the ground-water system to pumping is generally largest in areas where pumping occurs. Annual drawdown and recovery cycles of 1 to 10 feet are common in pumping areas. Long-term drawdown effects, where the water table has reached or is attempting to reach a new level in equilibrium with the pumping, are apparent in parts of the basin.
Since 2001, ground-water use in the upper Klamath Basin has increased by about 50 percent. Much of this increase has occurred in the area in and around the Bureau of Reclamation Klamath Project, roughly tripling ground-water pumping in that area. This focused increase in pumping has resulted in ground-water level declines in the pumped aquifer in excess of 10 to 15 feet over a large part of the Project between 2001 and 2004. If pumping rates of recent years are continued, the aquifer could achieve a new equilibrium; however, the final configuration of the water table (depth to water) and the spatial and temporal distribution of the resulting effects to streams are unknown. Historical water-level data suggest that the water table should recover from recent declines if pumping is reduced to pre-2001 rates.
Groundwater Simulation and Management Models for the Upper Klamath Basin, Oregon and California$0.00
Groundwater Simulation and Management Models for the Upper Klamath Basin, Oregon and CaliforniaU.S. Geological Survey, U.S. Bureau of Reclamation, Oregon Water Resources Department | May 5, 2012...Summary
The upper Klamath Basin encompasses about 8,000 square miles, extending from the Cascade Range east to the Basin and Range geologic province in...
The upper Klamath Basin encompasses about 8,000 square miles, extending from the Cascade Range east to the Basin and Range geologic province in south-central Oregon and northern California. The geography of the basin is dominated by forested volcanic uplands separated by broad interior basins. Most of the interior basins once held broad shallow lakes and extensive wetlands, but most of these areas have been drained or otherwise modified and are now cultivated. Major parts of the interior basins are managed as wildlife refuges, primarily for migratory waterfowl. The permeable volcanic bedrock of the upper Klamath Basin hosts a substantial regional groundwater system that provides much of the flow to major streams and lakes that, in turn, provide water for wildlife habitat and are the principal source of irrigation water for the basin’s agricultural economy.
Increased allocation of surface water for endangered species in the past decade has resulted in increased groundwater pumping and growing interest in the use of groundwater for irrigation. The potential effects of increased groundwater pumping on groundwater levels and discharge to springs and streams has caused concern among groundwater users, wildlife and Tribal interests, and State and Federal resource managers.
To provide information on the potential impacts of increased groundwater development, and to aid in the development of a groundwater management strategy, the U.S. Geological Survey, in collaboration with the Oregon Water Resources Department and the Bureau of Reclamation, has developed a groundwater model that can simulate the response of the hydrologic system to these new stresses.
The groundwater model was developed using the U.S. Geological Survey MODFLOW finite-difference modeling code and calibrated using inverse methods to transient conditions from 1989 through 2004 with quarterly stress periods. Groundwater recharge and agricultural and municipal pumping are specified for each stress period. All major streams and most major tributaries for which a substantial part of the flow comes from groundwater discharge are included in the model. Groundwater discharge to agricultural drains, evapotranspiration from aquifers in areas of shallow groundwater, and groundwater flow to and from adjacent basins also are simulated in key areas. The model has the capability to calculate the effects of pumping and other external stresses on groundwater levels, discharge to streams, and other boundary fluxes, such as discharge to drains.
Historical data indicate that the groundwater system in the upper Klamath Basin fluctuates in response to decadal climate cycles, with groundwater levels and spring flows rising and declining in response to wet and dry periods. Data also show that groundwater levels fluctuate seasonally and interannually in response to groundwater pumping. The most prominent response is to the marked increase in groundwater pumping starting in 2001. The calibrated model is able to simulate observed decadal-scale climate-driven fluctuations in the groundwater system as well as observed shorter-term pumping-related fluctuations.
Example model simulations show that the timing and location of the effects of groundwater pumping vary markedly depending on the pumping location. Pumping from wells close (within a few miles) to groundwater discharge features, such as springs, drains, and certain streams, can affect those features within weeks or months of the onset of pumping, and the impacts can be essentially fully manifested in several years. Simulations indicate that seasonal variations in pumping rates are buffered by the groundwater system, and peak impacts are closer to mean annual pumping rates than to instantaneous rates. Thus, pumping effects are, to a large degree, spread out over the entire year. When pumping locations are distant (more than several miles) from discharge features, the effects take many years or decades to fully impact those features, and much of the pumped water comes from groundwater storage over a broad geographic area even after two decades. Moreover, because the effects are spread out over a broad area, the impacts to individual features are much smaller than in the case of nearby pumping.
Simulations show that the discharge features most affected by pumping in the area of the Bureau of Reclamation’s Klamath Irrigation Project are agricultural drains, and impacts to other surface-water features are small in comparison.
A groundwater management model was developed that uses techniques of constrained optimization along with the groundwater flow model to identify the optimal strategy to meet water user needs while not violating defined constraints on impacts to groundwater levels and streamflows. The coupled groundwater simulation-optimization models were formulated to help identify strategies to meet water demand in the upper Klamath Basin. The models maximize groundwater pumping while simultaneously keeping the detrimental impacts of pumping on groundwater levels and groundwater discharge within prescribed limits. Total groundwater withdrawals were calculated under alternative constraints for 2 Groundwater Simulation and Management Models for the Upper Klamath Basin, Oregon and California drawdown, reductions in groundwater discharge to surface water, and water demand to understand the potential benefits and limitations for groundwater development in the upper Klamath Basin.
The simulation-optimization model for the upper Klamath Basin provides an improved understanding of how the groundwater and surface-water system responds to sustained groundwater pumping within the Bureau of Reclamation’s Klamath Project. Optimization model results demonstrate that a certain amount of supplemental groundwater pumping can occur without exceeding defined limits on drawdown and stream capture. The results of the different applications of the model demonstrate the importance of identifying constraint limits in order to better define the amount and distribution of groundwater withdrawal that is sustainable.