Ground-Water Hydrology of the Upper Klamath Basin, Oregon and California

Abstract

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 groundwater 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 groundwater movement in some areas. The regional groundwater 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.

Past and future water conflicts in the Upper Klamath Basin: An economic appraisal

“…Typically, groundwater levels have fallen during multiyear dry periods but have recovered completely during subsequent wet periods. Groundwater pumping in the basin outside the project area in the 2000 water year was approximately 150,000 ac ft [Gannett et al, 2007]. Reclamation water payments have provided further incentives for pumping, resulting in roughly 56,000 and 76,000 ac ft of additional pumping in 2003 and 2004, which is a 37% and 51% increase, respectively, in groundwater pumping over 2000 levels [McFarland et al, 2005].…”

“…Although the magnitude of subsurface inflow is unknown, it is likely very small [Gannett et al, 2007]. Precipitation varies widely across the basin, from a long-term average of 12-14 in.…”

“…[84] Between 2002 and 2006, the groundwater system in the basin has shown promising resilience in response to substantial water bank pumping, and the USGS has indicated that if these higher pumping levels are maintained, the groundwater system will eventually reach a new state of dynamic equilibrium (although the resulting effects to streams are unknown) [Gannett et al, 2007]. Absent the water bank requirements, our model suggests that the farm economy may only occasionally demand large volumes of groundwater, resulting in aggregate long-term demands that may be sustainable without substantially affecting regional groundwater levels.…”

“…[69] Although groundwater pumping may exceed sustainable levels in dry years [Gannett et al, 2007], natural recharge in wet years may be sufficient to sustain aquifer levels. If not, groundwater systems could be recharged more rapidly through effective conjunctive use following dry years where aquifers were heavily taxed.…”

The upside-down river: Reservoirs, algal blooms, and tributaries affect temporal and spatial patterns in nitrogen and phosphorus in the Klamath River, USA

“…1) having distinct geology, hydrology, and geomorphology. The upper basin (''upper river'' $94 km) is predominantly low relief (Appendix B) and is semiarid; average annual precipitation ranges from 330 to 1650 mm yr À1 (Western Regional Climate Center (WRCC), available at http://www.wrcc.dri.edu/summary/Climsmor.html) and the majority of hydrologic inputs are derived from groundwater and snowmelt runoff (Gannett et al, 2007). Klamath Falls, located in the upper basin, is the largest urban area in the watershed (2011 population: 66,300) but overall population in the region is rural, and the majority of land use (>50%) is agriculture and rangeland (NRC, 2008).…”