ABSTRACT Groundwater in the Upper Klamath Basin has always been an issue. The groundwater can be found in four different aquifers scattered throughout the basin. These include the sedimentary aquifer unit, the volcanic centers aquifer, the lower basalt aquifer (composed of basalt and volcanic ejecta), and the volcanic ash aquifer. The aquifers range from unconfined to confined, based on their composition and geologic locations (Gates). Water table levels tend to fluctuate seasonally with an average around 4026 feet above sea level. In terms of groundwater usage, Mgal/day of groundwater was pumped for irrigation in the year Even during drought cycles over half the Klamath basin (200,000 acres) is irrigated (ONRC). AQUIFERS Aquifers are lithologic layers of rock that hold water in their pore spaces and fractures. Without aquifers most people in arid regions, such as the Klamath Basin, would be water starved most of the year (Figure 2). The sedimentary aquifer unit, with its thickest deposits in the major valleys, is composed of alluvium, alluvial terrace, and shallow lake deposits with some interbedded basalt, rhyolite tuff deposits, and pumice. Wells completed in this aquifer unit have specific capacities of less then 5 gallons per minute per foot of drawdown (gpm/ft) and average 0.45 gpm/ft. These wells are generally yield sufficient amounts of water for domestic purposes (Gates). The volcanic centers aquifer is composed of basalt and volcanic ejecta (ash, cinders, and agglomerate). These deposits represent eruptive centers of old volcanoes. These deposits are most commonly found in mountainous areas but some local exposures are found on the valley floors. Their water bearing characteristics are excellent due to well-sorted coarse cinders, highly fractured lava rock, and scoriaceous interbeds. Wells constructed in this aquifer can yield the “big water” that every one in the Klamath Basin is looking for. Specific capacities range from 1 to 100 gpm/ft (Gates). AQUIFERS (CONT.) The lower basalt aquifer is comprised of basalt lava flows that occur beneath the sedimentary deposits of the Yonna Formation. The aquifer is highly permeable due to weathered surfaces, scoriaceous interbeds, and fractures in the basalt. Specific capacities commonly range from 33 to 500 gpm/ft and averages 145 gpm/ft. This aquifer, occurring most commonly below 1000 feet, is most commonly tapped for irrigation wells (Gates). The fourth aquifer unit is the volcanic ash aquifer. This unit is composed of volcanic ash, tuff, breccia, volcanic sediments, and occasional basalt flows. It underlies the lower basalt aquifer. The depth of this well exceeds 1000 feet and few wells in the area tap that deep so that the hydraulic characteristics of this aquifer are poorly defined. Generally, production rates are moderate to low and comparable to the sedimentary aquifer described above (Gates). INTRODUCTION There is a crisis in the Klamath Basin and it all revolves around water. Half the year the residents are trying to get rid of their excess water, in the form of snow, and the other half they need the water for personal and business uses. The four main aquifers in the area provide groundwater to the public but are experiencing depletion at a far greater rate than recharge. The main cause of the major aquifer draw down is irrigation. There will be a fight in the Klamath Basin as long as there are farmers and there is not enough water to go around during the summer months. WATER USE The majority of water use in the Klamath Basin is related to farmland. The Klamath Basin occupies approximately 474,000 acres of Southern Oregon and Northern California (Figure 1). Out of that total acreage over 200,000 acres were being irrigated inside the Klamath Basin in 2001, the year the water was shut off. Irrigators in the lower basin who receive water from the U.S. Bureau of Reclamation's Klamath Project are subject to oversight by federal agencies. However, irrigators in the upper basin above Upper Klamath Lake are virtually unregulated. Although the state is charged with managing water in the upper basin, the Water Resources Department fails to require most of these users to even measure how much they take from a river or stream (ONRC). As seen in Figure 4, irrigating land requires vast amounts of water. The Klamath Basin with its water problems, seems to have trouble coming up with enough to satiate the public. If there is a shortage of water and the government has not been able to effectively regulate what people take, what will happen to water resources in the future? REFERENCES CITED Gates, E., 2000, Ground Water Hydrology Of Four Proposed Project Areas In The Klamath Basin, Oregon. Fisher, B., Oregon Water Science Center Water-Use Program, U. S. Geological Survey, ONRC Press Release, 2001, Water Use in Klamath Basin Comes Under State Scrutiny, “Our Klamath Basin Water Crisis” Figures Figure Figure 2 – Figure 3 – Figure Groundwater In The Klamath Basin: An Upredictable Resource Prepared by: Caleb A. Downing Earth Science Dept., Western Oregon University GROUNDWATER USE The main aquifer that supplies the majority of the farmland in the Klamath Basin is being depleted by over 5 feet per year, and according to the Oregon Water Resources Department, it is not recovering (1). The year before the water crisis in the Klamath Basin, 2000, there was over 106 Mgal of groundwater being used for irrigation each day, nearly 44 Mgal of groundwater used for public supply per day and 0.91 Mgal/day for industrial use (Fisher). FIGURE 2: HOW AN AQUIFER WORKS FIGURE 1: UPPER KLAMATH BASIN FIGURE 3: WELL DATA SHOWING GROUNDWATER LEVELS FIGURE 4: IRRIGATION IN ACTION! CONCLUSSIONS The Klamath Basin is a hotbed of National debate. There is controversy surrounding how to manage water resources in the Klamath Basin. Many people believe that if there were better water storage solutions in place that there would not be any water useage problems. Extra stored water means that there would be less draw down on the aquifers and less use of surface water for public and agricultural practices. The aquifers are being depleted and unless current practices are drastically changed soon, we may never see them, in our life times, recharged to the levels they were at less than 100 years ago. WATER LEVELS Before the water was shut off in 2001 the average water level was around 4026 feet above sea level (ASL). After the water was shut off the average level of the water table dropped below 4005 feet ASL. Figure 3 shows the water levels in a well approximately five miles north of the California border over a 12 year span, it approximates the average water levels for the Klamath Basin. Water levels fluctuate quite a bit due to increased precipitation during the winter months when the basin is covered with snow. Conversely, the summer months see near drought conditions.