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Research about Stevens County, Washington

Source-linked reports with geographic coverage including Stevens County, Washington.

10 recordsLinked to original sources
USGS2012

Simulation of groundwater and surface-water resources and evaluation of water-management alternatives for the Chamokane Creek basin, Stevens County, Washington

A three-dimensional, transient numerical model of groundwater and surface-water flow was constructed for Chamokane Creek basin to better understand the groundwater-flow system and its relation to surface-water resources. The model described in this report can be used as a tool by water-management agencies and other stakeholders to quantitatively evaluate the effects of potential increases in groundwater pumping on groundwater and surface-water resources in the basin. The Chamokane Creek model was constructed using the U.S. Geological Survey (USGS) integrated model, GSFLOW. GSFLOW was developed to simulate coupled groundwater and surface-water resources. The model uses 1,000-foot grid cells that subdivide the model domain by 102 rows and 106 columns. Six hydrogeologic units in the model are represented using eight model layers. Daily precipitation and temperature were spatially distributed and subsequent groundwater recharge was computed within GSFLOW. Streamflows in Chamokane Creek and its major tributaries are simulated in the model by routing streamflow within a stream network that is coupled to the groundwater-flow system. Groundwater pumpage and surface-water diversions and returns specified in the model were derived from monthly and annual pumpage values previously estimated from another component of this study and new data reported by study partners. The model simulation period is water years 1980-2010 (October 1, 1979, to September 30, 2010), but the model was calibrated to the transient conditions for water years 1999-2010 (October 1, 1998, to September 30, 2010). Calibration was completed by using traditional trial-and-error methods and automated parameter-estimation techniques. The model adequately reproduces the measured time-series groundwater levels and daily streamflows. At well observation points, the mean difference between simulated and measured hydraulic heads is 7 feet with a root-mean-square error divided by the total difference in water levels of 4.7 percent. Simulated streamflow was compared to measured streamflow at the USGS streamflow-gaging station-Chamokane Creek below Falls, near Long Lake (12433200). Annual differences between measured and simulated streamflow for the site ranged from -63 to 22 percent. Calibrated model output includes a 31-year estimate of monthly water budget components for the hydrologic system. Five model applications (scenarios) were completed to obtain a better understanding of the relation between groundwater pumping and surface-water resources. The calibrated transient model was used to evaluate: (1) the connection between the upper- and middle-basin groundwater systems, (2) the effect of surface-water and groundwater uses in the middle basin, (3) the cumulative impacts of claims registry use and permit-exempt wells on Chamokane Creek streamflow, (4) the frequency of regulation due to impacted streamflow, and (5) the levels of domestic and stockwater use that can be regulated. The simulation results indicated that streamflow is affected by existing groundwater pumping in the upper and middle basins. Simulated water-management scenarios show streamflow increased relative to historical conditions as groundwater and surface-water withdrawals decreased.

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USGS2010

Hydrogeologic framework, groundwater and surface-water systems, land use, pumpage, and water budget of the Chamokane Creek basin, Stevens County, Washington

A study of the water resources of the unconsolidated groundwater system of the Chamokane Creek basin was conducted to determine the hydrogeologic framework, interactions of shallow and deep parts of the groundwater system with each other and the surface-water system, changes in land use and land cover, and water-use estimates. Chamokane Creek basin is a 179 mi2 area that borders and partially overlaps the Spokane Indian Reservation in southern Stevens County in northeastern Washington State. Aquifers within the Chamokane Creek basin are part of a sequence of glaciofluvial and glaciolacustrine sediment that may reach total thicknesses of about 600 ft. In 1979, most of the water rights in the Chamokane Creek basin were adjudicated by the United States District Court requiring regulation in favor of the Spokane Tribe of Indians' senior water right. The Spokane Tribe, the State of Washington, and the United States are concerned about the effects of additional groundwater development within the basin on Chamokane Creek. Information provided by this study will be used to evaluate the effects of potential increases in groundwater withdrawals on groundwater and surface-water resources within the basin. The hydrogeologic framework consists of six hydrogeologic units: The Upper outwash aquifer, the Landslide Unit, the Valley Confining Unit, the Lower Aquifer, the Basalt Unit, and the Bedrock Unit. The Upper outwash aquifer occurs along the valley floors of the study area and consists of sand, gravel, cobbles, boulders, with minor silt and (or) clay interbeds in places. The Lower aquifer is a confined aquifer consisting of sand and gravel that occurs at depth below the Valley confining unit. Median horizontal hydraulic conductivity values for the Upper outwash aquifer, Valley confining unit, Lower aquifer, and Basalt unit were estimated to be 540, 10, 19, and 3.7 ft/d, respectively. Many low-flow stream discharge measurements at sites on Chamokane Creek and its tributaries were at or near zero flow. The most notable exception is where Chamokane Creek is supported by discharge of large springs from the Upper outwash aquifer in the southern part of the basin. Most high-flow measurements indicated gains in streamflow (groundwater discharging to the stream). Large streamflow losses, however, were recorded near the north end of Walkers Prairie where streamflow directly recharges the Upper outwash aquifer. The similarity in seasonal water-level fluctuations in the Upper outwash aquifer and the Lower aquifer indicate that these systems may be fairly well connected. Land use and land cover change analysis indicates that Chamokane Creek basin has been dominated by forests with some pasture and agricultural lands with sparse residential development from the 1980s to present. Loss in forest cover represents the largest change in land cover in the basin between 1987 and 2009. This appears to be mostly due to forestry activities, especially in the northern part of the basin. Since 1987, more than 18,000 acres of evergreen forest have been logged and are at various stages of regrowth. Estimated average annual total groundwater pumpage in the basin increased from 224 million gallons per year (Mgal/yr) in 1980 to 1,330 Mgal/yr in 2007. The largest withdrawals during 2007 were to supply two fish hatcheries, with a combined total annual pumpage of about 1,150 Mgal. Annual groundwater pumpage values from 1980 through 2007 for the study area ranged from 21.1 to 28.9 Mgal/yr for domestic wells and 0.38 to 23.7 Mgal/yr for public supply. An approximate water budget for a typical year in the Chamokane Creek basin indicates that 19.6 in. of precipitation are balanced by 4.7 in. of streamflow discharge from the basin, and 14.9 in. of evapotranspiration.

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USGS2008

Determination of premining geochemical background and delineation of extent of sediment contamination in Blue Creek downstream from Midnite Mine, Stevens County, Washington

Geochemical and radionuclide studies of sediment recovered from eight core sites in the Blue Creek flood plain and Blue Creek delta downstream in Lake Roosevelt provided a stratigraphic geochemical record of the contamination from uranium mining at the Midnite Mine. Sediment recovered from cores in a wetland immediately downstream from the mine site as well as from sediment catchments in Blue Creek and from cores in the delta in Blue Creek cove provided sufficient data to determine the premining geochemical background for the Midnite Mine tributary drainage. These data provide a geochemical background that includes material eroded from the Midnite Mine site prior to mine development. Premining geochemical background for the Blue Creek basin has also been determined using stream-sediment samples from parts of the Blue Creek, Oyachen Creek, and Sand Creek drainage basins not immediately impacted by mining. Sediment geochemistry showed that premining uranium concentrations in the Midnite Mine tributary immediately downstream of the mine site were strongly elevated relative to the crustal abundance of uranium (2.3 ppm). Cesium-137 (137Cs) data and public records of production at the Midnite Mine site provided age control to document timelines in the sediment from the core immediately downstream from the mine site. Mining at the Midnite Mine site on the Spokane Indian Reservation between 1956 and 1981 resulted in production of more than 10 million pounds of U3O8. Contamination of the sediment by uranium during the mining period is documented from the Midnite Mine along a small tributary to the confluence of Blue Creek, in Blue Creek, and into the Blue Creek delta. During the period of active mining (1956?1981), enrichment of base metals in the sediment of Blue Creek delta was elevated by as much as 4 times the concentration of those same metals prior to mining. Cadmium concentrations were elevated by a factor of 10 and uranium by factors of 16 to 55 times premining geochemical background determined upstream of the mine site. Postmining metal concentrations in sediment are lower than during the mining period, but remain elevated relative to premining geochemical background. Furthermore, the sediment composition of surface sediment in the Blue Creek delta is contaminated. Base-metal contamination by arsenic, cadmium, lead, and zinc in sediment in the delta in Blue Creek cove is dominated by suspended sediment from the Coeur d?Alene mining district. Uranium contamination in surface sediment in the delta of Blue Creek cove extends at least 500 meters downstream from the mouth of Blue Creek as defined by the 1,290-ft elevation boundary between lands administered by the National Park Service and the Spokane Indian Tribe. Comparisons of the premining geochemical background to sediment sampled during the period the mine was in operation, and to the sediment data from the postmining period, are used to delineate the extent of contaminated sediment in Blue Creek cove along the thalweg of Blue Creek into Lake Roosevelt. The extent of contamination out into Lake Roosevelt by mining remains open.

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USGS1976

Ground magnetic and VLF studies at Midnite uranium mine, Stevens County, Washington

Ground magnetic and E-mode VLF measurements were made at more than 200 stations at the Midnite uranium Mine, Stevens County, Washington. The equipment was found to be light and foolproof, and each set of data was collected in one day, exclusive of surveying and marking the station points. The maps of contoured magnetic and VLF data resembled geologic maps of the area, showing many common features, as well as a few unique features on each map. Each showed some evidence of a small normal fault cutting the region; taken together, the evidence for this fault was judged to be much stronger, so that further structural details were inferred. Because of soil cover and inadequate outcrops, the presence of this fault had hitherto been unsuspected. A target area for further uranium mineralization north of the fault was indicated by this quick, inexpensive geophysical survey. The drilling program which Midnite Mine management had underway at that time had already outlined a mineralized zone in the indicated area.

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USGS1976

Uranium and trace element data on stream sediments in the Midnite Mine area, Stevens County, eastern Washington

Seventy-two stream sediment samples were collected near the Midnite mine in southern Stevens County, eastern Washington. The -82 mesh fraction of these samples was analyzed for acid extractable U, Fe, Mn, Cu, Pb, Zn, Ni, Co, Mo, Cd, Cr, Ag, V, and Se and total Fe, Mn, Hg, As, and organic C. Sample site locations and descriptions, the methods of sample collection, preparation and analysis, and the analytic data are presented.

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USGS1950

Western Molybdenum Company mine, Chewelah district, Stevens County, Washington

The Western Molybdenum Company mine was opened many years ago to obtain copper. The only production was several cars of crude copper ore shipped during World War I. An unsuccessful attempt to produce molybdenum was made in 1939-1941. The deposit consists of steeply dipping, northeast-striking veins in monzonite and marble, carrying molybdenite, pyrite, chalcopyrite, scheelite, and some quartz. Northwest- striking faults cut and offset the veins as much as 10 feet. The main vein, which contains all the known ore, is developed by four levels to a depth of 293 feet. It contains ore shoots from a few inches to 4 feet wide and up to 130 feet long, carrying about 1 percent MoS 2 , 1 percent Cu, and 0.15 percent W0 3 .

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