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At least 613 records · Page 34Linked to original sources

Principal facts of gravity data for the Greenville 1 degree by 2 degrees Quadrangle, Georgia, North Carolina, and South Carolina

This report presents hydrologic data used in the Southern Sand Hills hydrogeology study, which encompasses an area of approximately 4,330 square miles in west-central Nebraska. These data include summary logs of 64 test holes drilled in or adjacent to the study area. Water level data for 240 wells are included. These wells were measured in spring and fall of 1982 and spring of 1983. Water quality samples were collected from 62 irrigation wells. Water quality data include analyses for 18 routine constituents on samples from all wells and analyses for 8 trace constituents on samples from 25 wells. Rainfall data were collected at 30 sites by local observers from April 1982 to October 1983. Surface water data for 103 stream sites in the study area are included. Water discharge was measured at these sites as part of seepage surveys conducted from 1978 to 1982 to determine where and how much streams were gaining or losing water. (USGS)

Open-File Report↗

Estimates of ground-water recharge rates for two small basins in central Nevada

Estimates of ground-water recharge rates developed from hydrologic modeling studies are presented for 3-Springs and East Stewart basins. two small basins (analog sites) located in central Nevada. The analog-site studies were conducted to aid in the estimation of recharge to the paleohydrologic regime associated with ground water in the vicinity of Yucca Mountain under wetter climatic conditions. The two analog sites are located to the north and at higher elevations than Yucca Mountain, and the prevailing (current) climatic conditions at these sites is thought to be representative of the possible range of paleoclimatic conditions in the general area of Yucca Mountain during the Quaternary. Two independent modeling approaches were conducted at each of the analog sites using observed hydrologic data on precipitation, temperature, solar radiation stream discharge, and chloride-ion water chemistry for a 6-year study period (October 1986 through September 1992). Both models quantify the hydrologic water-balance equation and yield estimates of ground-water recharge, given appropriate input data. The first model uses a traditional approach to quantify watershed hydrology through a precipitation-runoff modeling system that accounts for the spatial variability of hydrologic inputs, processes, and responses (outputs) using a dailycomputational time step. The second model is based on the conservative nature of the dissolved chloride ion in selected hydrologic environments, and its use as a natural tracer allows the computation of acoupled, water and chloride-ion, mass-balance system of equations to estimate available water (sum ofsurface runoff and groundwater recharge). Results of the modeling approaches support the conclusion that reasonable estimates of average-annual recharge to ground water range from about 1 to 3 centimeters per year for 3-Springs basin (the drier site), and from about 30 to 32 centimeters per year for East Stewart basin (the wetter site). The most reliable results are those derived from a reduced form of the chloride-ion model because they reflect integrated, basinwide processes in terms of only three measured variables: precipitation amount, precipitation chemistry, and streamflow chemistry.

Nevada↗

Groundwater-supported evapotranspiration within glaciated watersheds under conditions of climate change

This paper analyzes the effects of geology and geomorphology on surface-water/-groundwater interactions, evapotranspiration, and recharge under conditions of long-term climatic change. Our analysis uses hydrologic data from the glaciated Crow Wing watershed in central Minnesota, USA, combined with a hydrologic model of transient coupled unsaturated/saturated flow (HYDRAT2D). Analysis of historical water-table (1970-1993) and lake-level (1924-2002) records indicates that larger amplitude and longer period fluctuations occur within the upland portions of watersheds due to the response of the aquifer system to relatively short-term climatic fluctuations. Under drought conditions, lake and water-table levels fell by as much as 2-4 m in the uplands but by 1 m in the lowlands. The same pattern can be seen on millennial time scales. Analysis of Holocene lake-core records indicates that Moody Lake, located near the outlet of the Crow Wing watershed, fell by as much as 4 m between about 4400 and 7000 yr BP. During the same time, water levels in Lake Mina, located near the upland watershed divide, fell by about 15 m. Reconstructed Holocene climate as represented by HYDRAT2D gives somewhat larger drops (6 and 24 m for Moody Lake and Lake Mina, respectively). The discrepancy is probably due to the effect of three-dimensional flow. A sensitivity analysis was also carried out to study how aquifer hydraulic conductivity and land-surface topography can influence water-table fluctuations, wetlands formation, and evapotranspiration. The models were run by recycling a wet year (1985, 87 cm annual precipitation) over a 10-year period followed by 20 years of drier and warmer climate (1976, 38 cm precipitation). Model results indicated that groundwater-supported evapotranspiration accounted for as much as 12% (10 cm) of evapotranspiration. The aquifers of highest hydraulic conductivity had the least amount of groundwater-supported evapotranspiration owing to a deep water table. Recharge was even more sensitive to aquifer hydraulic conductivity, especially in the lowland regions. These findings have important implications for paleoclimatic studies, because the hydrologic response of a surface-water body will vary across the watershed to a given climate signal. ?? 2005 Elsevier B.V. All rights reserved.

Conference Paper↗

Recent (2001-09) hydrologic history and regionalization studies in Texas-Statistical characterization of storms, floods, and rainfall-runoff relations

As part of numerous cooperative studies investigating rainfall and streamflow during 1991-2009 with the Texas Department of Transportation and Texas Commission on Environmental Quality, the U.S. Geological Survey (USGS) published about 20 reports describing either historical streamflow conditions (hydrologic history) in Texas or the results of studies involving regional rainfall and streamflow statistics (regionalization studies). Both types of studies are widely used in engineering and scientific applications. Long-term rainfall and streamflow records are essential for deriving reliable rainfall and streamflow statistics. Whereas the need for such records is regionwide, rainfall and streamflow records are site-specific. The USGS has pioneered ways to mathematically transfer site-specific rainfall and streamflow information to provide regional statistical models. In addition to publishing reports describing historical hydrologic data at many monitored locations throughout Texas, the USGS has published reports describing regional models for estimating rainfall and streamflow statistics at unmonitored locations. The primary objectives of these regionalization studies were to provide historical perspectives of streamflow conditions in Texas or estimates of specific statistics of rainfall or streamflow. Statistics such as 6-hour, 1-percent annual exceedance rainfall (a large storm) or 2-percent annual exceedance streamflow (a substantial flood) can be estimated for locations lacking sufficient direct observations of rainfall and streamflow data. This fact sheet provides a brief synopsis of 12 recent (2001-09) USGS hydrologic history and regionalization studies in Texas organized thematically and chronologically.

Fact Sheet↗

Water resources data, Massachusetts and Rhode Island, water year 1994

Water resources data for the 1994 water year for Massachusetts and Rhode Island consists of records of stage, discharge, and water quality of streams; contents of lakes and reservoirs; and ground-water levels. This report contains discharge records for 83 gaging stations, month end contents of 4 lakes and reservoirs, water quality at 31 gaging stations, and water levels for 136 observation wells. Data also are included for 60 low-flow partial-record stations. Miscellaneous hydrologic data were collected at various sites that were not a part of the systematic data-collection program and are published as miscellaneous discharge measurements and quality of ground water. A few pertinent stations in bordering States are also included in this report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Massachusetts and Rhode Island.

Massachusetts, Rhode Island↗

Water resources data, Massachusetts and Rhode Island, water year 1995

Water resources data for the 1995 water year for Massachusetts and Rhode Island consists of records of stage, discharge, and water quality of streams; contents of lakes and reservoirs; and ground-water levels. This report contains discharge records for 87 gaging stations, monthend contents of 3 lakes and reservoirs, water quality at 32 gaging stations, and water levels for 136 observation wells. Data also are included for 47 low-flow partial-record stations. Miscellaneous hydrologic data were collected at various sites that were not a part of the systematic data-collection program and are published as miscellaneous discharge measurements and quality of ground water. A few pertinent stations in bordering States are also included in this report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Massachusetts and Rhode Island.

Massachusetts, Rhode Island↗

Water resources data, Massachusetts and Rhode Island, water year 1996

Water resources data for the 1996 water year for Massachusetts and Rhode Island consists of records of stage, discharge, and water quality of streams; contents of lakes and reservoirs; and ground-water levels. This report contains discharge records for 88 gaging stations, month end contents of 4 lakes and reservoirs, water quality at 16 gaging stations, and water levels for 143 observation wells. Data also are included for 35 low-flow partial-record stations. Miscellaneous hydrologic data were collected at various sites that were not a part of the systematic data-collection program and are published as miscellaneous discharge measurements. A few pertinent stations in bordering States are also included in this report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Massachusetts and Rhode Island.

Massachusetts, Rhode Island↗

Hydrology and geomorphology of the Taiya River near the West Creek Tributary, southeast Alaska

The Taiya River flows through the Chilkoot Trail Unit of Klondike Gold Rush National Historical Park in southeast Alaska, which was founded to preserve cultural and historical resources and further understanding of natural processes active in the surrounding coastal-to-subarctic basin. Riverine processes exert an important influence on ecologically important boreal toad ( Anaxryus boreas boreas ), salmon [chum salmon ( Oncorhynchus keta ), pink salmon ( O. gorbushca ), and coho salmon ( O. kisutch )], and eulachon ( Thaleichthys pacificus ) habitats, erosion of the historic ghost town of Dyea and other cultural and historical artifacts, and recreational opportunities in the lower 7.5 kilometers (km) of the Taiya River valley bottom. Recurrent consideration of hydroelectric development in West Creek upstream of the park since the 1980s has included proposals for damming and diverting West Creek, which could alter the delivery of water and sediment to this section of the Taiya River. To improve understanding of the hydrologic dependence of park resources for the purposes of guiding effective monitoring and conservation, this study, conducted by the U.S. Geological Survey in cooperation with the National Park Service, used a review of hydrologic data, collection of discrete suspended sediment data, geomorphic mapping, and analysis of historical aerial and ground photographs in a reconnaissance of formative geomorphic processes and hydrologic conditions in the lower 7.5 km of the Taiya River valley bottom. Streamflow and suspended sediment data collected at the U.S. Geological Survey streamgages on the Taiya River and West Creek, combined with historical data, document conditions consistent with streams draining strongly glacierized basins in Alaska. Suspended sediment concentrations from samples collected concurrently over six varying flow levels during 2017–18 ranged from 6 to 284 milligrams per liter (mg/L) for the Taiya River and 13 to 162 mg/L for West Creek, which are similar to or slightly higher than historical values. For the common period of record (1970–77), correlation of daily mean discharge between the two streams was strongest (Pearson’s r = 0.97) during the prolonged May–October high-flow season and weakest ( r = 0.90) during the November–April low-flow season, when West Creek daily mean discharge was proportionally higher. For the Taiya River, streamflow data compared between the available periods of record (1970–77 and 2004–17) showed no decadal-scale patterns in mean annual discharge but did show a shift toward an earlier spring snowmelt pulse. Notable flooding in the Taiya River Basin includes glacial lake outburst floods from the Nourse River valley prior to and during the 1897–98 Gold Rush, a 2002 glacial lake outburst flood from the West Creek valley, and a 1967 rainfall-generated flood. Geomorphic mapping identified four categories of surfaces in the valley bottom—active main stem, abandoned main stem, alluvial fans, and emergent tidal surfaces. Using the maps, main-stem surfaces were subdivided into age categories to identify channel migration patterns from prior to 1940s to 2018. The valley bottom is dominated by active or abandoned channels of the Taiya River except at the extensive low-angle West Creek fan. The active main stem presently supports a mostly single-thread channel with bars and a few sloughs, but the channel actively moved and sometimes was braided within multiple, wider unvegetated corridors in 1894 and earlier. An inventory of 29 off-main-stem channels identified for the study indicates that abandoned main stem channels provide local topographic lows that can intercept groundwater or sustain tributary flow, facilitating the formation of most nonestuarine wetlands in the valley and sustaining important boreal toad breeding habitat. Within the active main stem corridor, the channel has episodically built and reworked meanders and bars, eroding more than one-half of the historic Dyea townsite, in response to glacially controlled delivery of water and sediment, flooding, inputs from West Creek, local features including large woody debris and beaver dams, and rapid uplift from isostatic rebound. West Creek has constructed a large, persistent fan, provoked kilometer-scale Taiya River channel change near the confluence, constructively added to high-season streamflow that affects Taiya River channel migration capacity, disproportionately contributed early-season streamflow, and possibly contributed to groundwater levels in the valley bottom. The progressive narrowing and stability of the main stem corridor, possibly a result of reduction in the magnitude or frequency of glacial lake outburst floods or glacial sediment delivery to streams, indicates less active future reworking of abandoned main-stem surfaces or regeneration of wetland features. The fluvial history of the Taiya River valley bottom collectively indicates continued channel change within a limited corridor, relative stability in wetland locations but uncertainty in stability of groundwater supply to them, and channel incision and extension in response to uplift.

Alaska↗

Geohydrologic sections, Cache Valley, Utah and Idaho

This report was prepared as a part of a study of the ground-water resources of Cache Valley, Utah and Idaho. The study by the U.S. Geo- logical Survey was made during 1967-70 in cooperation with the Utah Department of Natural Resources, Division of Water Rights. The U.S. Bureau of Reclamation and the U.S. Soil Conservation Service cooperated by providing services; and counties, cities, irrigation districts, and some local organizations and businesses in both Utah and Idaho cooperated financially through the Utah Department of Natural Resources. In addition to this report, results of the study are presented in a basic-data release (McGreevy and Bjorklund, 1970) and in an interpretive report in preparation. Geologic and hydrologic data are combined and presented on a series of cross sections. Geologic contacts and faults or fault zones are based on indicated well logs, on the geologic map in the interpretive report (in preparation) , and on gravity data by Peterson and Oriel (1970).

Idaho, Utah↗

Hydrogeologic and water-quality data for the explosive experimental area, Naval Surface Warfare Center, Dahlgren Site, Dahlgren, Virginia

Hydrogeologic and water-quality data were collected at the Explosive Experimental Area, Naval Surface Warfare Center, Dahlgren Site at Dahlgren, Virginia, as part of a hydrogeologic assessment of the shallow aquifer system begun in 1993. The U.S. Geological Survey conducted this study to provide the U.S. Navy with hydrogeologic data to aid in the evaluation of the effects from remediation of contaminated sites and to protect against additional contamination. This report describes the ground-water observation- well network, hydrogeologic, and water-quality data collected between October 1993 and April 1995. The report includes a description of the locations and construction of 28 observation wells on the Explosive Experimental Area. Hydrogeologic data include lithologic logs, geophysical logs, and vertical hydraulic conductivity measurements of selected core intervals. Hydrologic data include synoptic and hourly measurements of ground-water levels, and observation-well slug tests to determine horizontal hydraulic conductivity. Water-quality data include analyses of major dissolved constituents in ground water and surface water.

Virginia↗

Ground-water data of selected test holes and wells along the Verdigris River in Wagoner and Rogers Counties, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Verdigris River in Wagoner and Rogers Counties readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for Sequoyah County, LeFlore-Haskell Counties, and Muskogee County are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Oklahoma↗

Ground-water data of selected test holes and wells along the Arkansas River in LeFlore and Haskell Counties, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Arkansas River in Le Flore and Haskell Counties readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for Sequoyah County, Muskogee County, and Wagoner-Rogers Counties are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Open-File Report↗

Ground-water data of selected test holes and wells along the Arkansas river in Muskogee County, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Arkansas River in Muskogee County readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for Sequoyah County, LeFlore-Haskell Counties, and Wagoner-Rogers Counties are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Open-File Report↗

Ground-water data of selected test holes and wells along the Arkansas River in Sequoyah County, Oklahoma

The data in this report were collected during the period 1958-64 by the U.S. Geological Survey in cooperation with the U.S. Army, Corps of Engineers, as part of a comprehensive study of the ground-water resources of the alluvium along the Arkansas and Verdigris Rivers between Moffett and Catoosa, Oklahoma (fig. 1). The purpose of this report is to make the hydrologic data obtained during the study of ground water in the alluvium along the Arkansas River in Sequoyah County readily available to the public. The data in this report should be useful in predicting geologic and hydrologic conditions when drilling new wells. Table 1 gives information on the sizes, depths, yields, and other characteristics of wells in the area. The table also provides a key to the additional information for each well site given in tables 2 through 6. Table 2 gives logs for the materials penetrated at test holes and wells in the report area; table 3 gives depths to water measured in wells; table 4 includes chemical analyses of water from wells; table 5 gives laboratory determinations of particle-size distribution of earth samples collected from test holes and wells; and table 6 gives coefficients of permeability and other hydrologic properties of earth samples from the selected test holes. Similar data for LeFlore-Haskell Counties, Muskogee County, and Wagoner-Rogers Counties are available in other open-file reports. An interpretive report, 'Hydrology of the alluvium of the Arkansas River, Muskogee, Oklahoma, to Fort Smith, Arkansas,' by Harry H. Tanaka and Jerrald R. Hollowell will be published as U.S. Geological Survey Water-Supply Paper 1809-T.

Open-File Report↗

Development of a decision support tool for water and resource management using biotic, abiotic, and hydrological assessments of Topock Marsh, Arizona

Topock Marsh is a large wetland adjacent to the Colorado River and the main feature of Havasu National Wildlife Refuge (Havasu NWR) in southern Arizona. In 2010, the U.S. Fish and Wildlife Service (FWS) and Bureau of Reclamation began a project to improve water management capabilities at Topock Marsh and protect habitats and species. Initial construction required a drawdown, which caused below-average inflows and water depths in 2010–11. U.S. Geological Survey Fort Collins Science Center (FORT) scientists collected an assemblage of biotic, abiotic, and hydrologic data from Topock Marsh during the drawdown and immediately after, thus obtaining valuable information needed by FWS. Building upon that work, FORT developed a decision support system (DSS) to better understand ecosystem health and function of Topock Marsh under various hydrologic conditions. The DSS was developed using a spatially explicit geographic information system package of historical data, habitat indices, and analytical tools to synthesize outputs for hydrologic time periods. Deliverables include high-resolution orthorectified imagery of Topock Marsh; a DSS tool that can be used by Havasu NWR to compare habitat availability associated with three hydrologic scenarios (dry, average, wet years); and this final report which details study results. This project, therefore, has addressed critical FWS management questions by integrating ecologic and hydrologic information into a DSS framework. This DSS will assist refuge management to make better informed decisions about refuge operations and better understand the ecological results of those decisions by providing tools to identify the effects of water operations on species-specific habitat and ecological processes. While this approach was developed to help FWS use the best available science to determine more effective water management strategies at Havasu NWR, technologies used in this study could be applied elsewhere within the region.

Arizona↗

Hydrology of potential mining areas in the Warrior coal field, Alabama

Hydrologic data for four small basins and for numerous other sites in the Warrior coal field are used to define the potential impact of surface mining on water resources. Bear and Blue Creek basins are underlain predominantly by relatively impermeable consolidated rocks in the Pottsville Formation. Turkey and Yellow Creek basins are underlain predominantly by permeable unconsolidated rocks in the Coker Formation. Well yields from the Pottsville Formation generally range from 0 to 5 gallons per minute and those from the Coker Formation generally range from 5 to 100 gallons per minute. With the exception of locally objectional concentrations of dissolved iron and manganese, ground water in the basins is suitable for most uses. Streamflow distribution reflects seasonal precipitation. Storm runoff is characterized by concentrated peakflows of short duration that rapidly recede to low flow. Streams draining basins underlain mainly by the Pottsville Formation frequently go dry, whereas those draining basins underlain chiefly by the Coker Formation have well-sustained low flows. Surface water is generally acidic and low in dissolved solids. Water in streams draining basins underlain chiefly by the Pottsville Formation is slightly more mineralized and less acidic than water in streams draining areas underlain chiefly by the Coker Formation. Climatic, physiographic, hydrologic, and land-use data are analyzed by regressions to derive relations for estimating water quality in streams draining mined and unmined areas. The impacts of mining on the hydrologic systems are identified as increased erosion and sedimentation, baseflow augmentation, decline in groundwater levels, and degradation of water quality. A digital model was calibrated to simulate streamflow for Bear, Blue, and Yellow Creeks under unmined conditions. The model, when calibrated and verified under mined and unmined conditions, can be coupled with developed water-quality relationships. This will permit a general examination of .surface-water characteristics (quantity and quality), and estimation of hydrologic impacts that will result from surface mining.

Open-File Report↗

Isotopic characterization of three groundwater recharge sources and inferences for selected aquifers in the upper Klamath Basin of Oregon and California, USA

Stable isotope (??D and ??18O) signatures of three principal groundwater recharge areas in the 21,000-km2 upper Klamath Basin are used to infer recharge sources for aquifers in the interior parts of the basin. Two of the principal recharge areas, the Cascade Range on the western and southern margin of the basin and uplands along the eastern margin, are defined by mean annual precipitation that exceeds approximately 60 cm. A third recharge area coincides with the extensive irrigation canal system in the south central part of the basin. The stable isotope signature for Cascade Range groundwater falls near the global meteoric water line (GMWL). The stable isotope signature for the groundwater of the eastern basin uplands also falls near the GMWL, but is depleted in heavy isotopes relative to the Cascade Range groundwater. The stable isotope signature for water from the irrigation canal system deviates from the GMWL in a manner indicative of fractionation by evaporation. Groundwater provenance was previously unknown for two aquifers of interest: that supplying deep (225-792 m), large-capacity irrigation wells along the Oregon-California border, and that of the geothermal system near Klamath Falls. Groundwater produced by the deep irrigation wells along the Oregon-California border appears to be a mixture of eastern-basin groundwater and water with an evaporative isotopic signature. The component with an evaporative isotopic signature appears in some places to consist of infiltrated irrigation water. Chloride data suggest that much of the component with the evaporative isotopic signature may be coming from an adjacent subbasin. After accounting for the 18O shift common in geothermal waters, isotope data suggest that the geothermal groundwater in the upper Klamath Basin may emanate from the eastern basin uplands. Findings demonstrate that stable isotope and chloride data can illuminate certain details of a regional groundwater flow system in a complex geologic setting where other hydrologic data are ambiguous. ?? 2007 Elsevier B.V. All rights reserved.

Journal of Hydrology↗

Color photographs for water resources studies

Air-photo interpretation is very well suited to water resources studies where limited observations of hydrologic data must be extended to regional characteristics for large areas. It is also useful in monitoring the hydrologic regimen of an area to detect possible changes. Color aerial photography is generally superior to black-and-white photography for these water resources investigations. Depth penetration through water, and excellent discrimination of water indicators, such as vegetation, are its -main assets. Meaningful interpretation of the photography depends on adequate ground control data. Experiences of the Water Resources Division, U. S. Geological Survey, indicate that the best interpretation is done by professional personnel-engineers, geologists, and water chemists intimately associated with a particular water resources project for which the photography has been obtained.

Photogrammetric Engineering↗