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At least 757 records · Page 42Linked to original sources

Magnetotelluric and audiomagnetotelluric groundwater survey along the Humu'ula portion of Saddle Road near and around the Pohakuloa Training Area, Hawaii

The Pohakuloa Training Area (PTA), operated by the U.S. Army on the Big Island of Hawaii, is in need of a reliable potable water supply to sustain ongoing operations by staff and trainees. In an effort to acquire baseline hydrologic data with which to develop a plan for providing that water, a series of magnetotelluric (MT) geophysical surveys was performed that spanned the Mauna Loa/Mauna Kea Saddle region of Hawaii Island. These surveys provided electrical resistivity profiles and resistivity maps at several elevations along the axis of the field measurements that can be interpreted to yield information on the depth to the water table. In 2004 a preliminary sequence of 23 audiomagnetotelluric (AMT) soundings was collected along Saddle Road extending from the Waikii Ranch area, west of the PTA, to Department of Hawaiian Home Lands Humu'ula properties east of the Mauna Kea access road. The results of those soundings showed that highly resistive rocks, consistent with dry basalts, were present to depths of at least one kilometer, the maximum depth to which the AMT technique can reliably reach in Hawaii's rocks. A second survey was conducted in 2008 using MT instruments capable of recovering resistivity data to depths of several kilometers below sea level where saturated formations are known to exist. A total of 30 MT soundings was performed along a roughly east to west transect that extended from the (recently acquired) Keamuku PTA lands on the west to as far as the County of Hawaii's upper Kaumana water supply well to the east. Inversion and processing of the field data yielded an electrical cross-section following the Saddle that roughly parallels the geologic contact between the Mauna Kea and Mauna Loa lavas. Several additional electrical sections were constructed normal to the main transect to investigate the three-dimensional nature of the contact. These resistivity data and models suggest that the elevation of saturated rock in places are 400 to 600 meters above mean sea level beneath the surveyed region. Highest elevations for water-saturated zones based upon preferred electrical models are located between training area 3 and training area 6 southwest of training area 4.

Hawai'i↗

Ground-water resources in the lower Milliken--Sarco--Tulucay Creeks area, southeastern Napa County, California, 2000-2002

Ground water obtained from individual private wells is the sole source of water for about 4,800 residents living in the lower Milliken-Sarco-Tulucay Creeks area of southeastern Napa County. Increases in population and in irrigated vineyards during the past few decades have increased water demand. Estimated ground-water pumpage in 2000 was 5,350 acre-feet per year, an increase of about 80 percent since 1975. Water for agricultural irrigation is the dominant use, accounting for about 45 percent of the total. This increase in ground-water extraction has resulted in the general decline of ground-water levels. The purpose of this report is to present selected hydrologic data collected from 1975 to 2002 and to quantify changes in the ground-water system during the past 25 years. The study area lies in one of several prominent northwest-trending structural valleys in the North Coast Ranges. The area is underlain by alluvial deposits and volcanic rocks that exceed 1,000 feet in thickness in some places. Alluvial deposits and tuff beds in the volcanic sequence are the principal source of water to wells. The ground-water system is recharged by precipitation that infiltrates, in minor amounts, directly on the valley floor but mostly by infiltration in the Howell Mountains. Ground water moves laterally from the Howell Mountains into the study area. Although the area receives abundant winter precipitation in most years, nearly half of the precipitation is lost as surface runoff to the Napa River. Evapotranspiration also is high, accounting for nearly one-half of the total precipitation received. Because of the uncertainties in the estimates of precipitation, runoff, and evapotranspiration, a precise estimate of potential ground-water recharge cannot be made. Large changes in ground-water levels occurred between 1975 and 2001. In much of the western part of the area, water levels increased; but in the central and eastern parts, water levels declined by 25 to 125 feet. Ground-water extraction produced three large pumping depressions in the northern and east-central parts of the area. The general decline in ground-water levels is a result of increases in ground-water pumpage and possibly changes in infiltration capacity caused by changes in land use. Ground-water-level declines during 1960-2002 are evident in the records for 9 of 10 key monitoring wells. In five of these wells, water levels dropped by greater than 20 feet since the 1980s. The largest water-level declines have occurred since the mid 1970s, corresponding with a period of accelerated well construction and ground-water extraction. Analysis of samples from 15 wells indicates that the chemical quality of ground water in the study generally is acceptable. However, arsenic concentrations in samples from five wells exceed the U.S. Environmental Protection Agency primary drinking-water standard of 10 micrograms per liter, and iron concentrations in samples from five wells exceed the U.S. Environmental Protection Agency and the California Department of Health Services secondary drinking-water standard of 300 micrograms per liter. Water from 12 of 15 wells sampled contained concentrations of manganese that exceed the U.S. Environmental Protection Agency and the California Department of Health Services secondary drinking-water standard of 50 micrograms per liter. Two wells produced water that had boron in excess of the California Department of Health Services action level of 1 milligram per liter. Stable isotope, chlorofluorocarbon, and tritium data indicate that ground water in the area is a mixture of waters that recharged the aquifer system at different times. The presence of chlorofluorocarbons and tritium in water from the study area is evidence that modern recharge (post 1950) does take place. Water-temperature logs indicate that ground-water temperatures throughout the study area exceed 30?C at depths in excess of 600 feet. Further, water at

Water-Resources Investigations Report↗

Hydrologic data from an area southwest of Tallahassee, Florida, where municipal wastewater effluent is applied by spray irrigation

The effects of spray irrigation using municipal wastewater effluent on a ground-water system (in particular, on the water of the Floridan aquifer) were investigated. The area irrigated was 4 miles southwest of Tallahassee, Florida, on an area covered in part by pine forest and in part by selected grasses and forage crops. Hydrologic and geologic data were collected from 1972 to 1981. Hydrologic data include ground-water levels, water quality, and spray-irrigation rates. Ground-water level measurements were made at 60 wells. Water-quality samples were collected at 1 municipal wastewater effluent site, 3 springs, 17 soil sites, and 64 wells. Water-quality data were obtained from physical, chemical, and bacteriological analyses. Geologic data include geophysical logs and lithologic descriptions of 34 wells. (USGS)

Open-File Report↗

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↗

Origin and characteristics of discharge at San Marcos Springs, south-central Texas

The Edwards aquifer in south-central Texas is one of the most productive aquifers in the Nation and is the primary source of water for the rapidly growing San Antonio area. Springs issuing from the Edwards aquifer provide habitat for several threatened and endangered species, serve as locations for recreational activities, and supply downstream users. Comal Springs and San Marcos Springs are major discharge points for the Edwards aquifer, and their discharges are used as thresholds in groundwater management strategies. Regional flow paths originating in the western part of the aquifer are generally understood to supply discharge at Comal Springs. In contrast, the hydrologic connection of San Marcos Springs with the regional Edwards aquifer flow system is less understood. During November 2008–December 2010, the U.S. Geological Survey, in cooperation with the San Antonio Water System, collected and analyzed hydrologic and geochemical data from springs, groundwater wells, and streams to gain a better understanding of the origin and characteristics of discharge at San Marcos Springs. During the study, climatic and hydrologic conditions transitioned from exceptional drought to wetter than normal. The wide range of hydrologic conditions that occurred during this study—and corresponding changes in surface-water, groundwater and spring discharge, and in physicochemical properties and geochemistry—provides insight into the origin of the water discharging from San Marcos Springs. Three orifices at San Marcos Springs (Deep, Diversion, and Weissmuller Springs) were selected to be representative of larger springs at the spring complex. Key findings include that discharge at San Marcos Springs was dominated by regional recharge sources and groundwater flow paths and that different orifices of San Marcos Springs respond differently to changes in hydrologic conditions; Deep Spring was less responsive to changes in hydrologic conditions than were Diversion Spring and Weissmuller Spring. Also, San Marcos Springs discharge is influenced by mixing with a component of saline groundwater.

Texas↗

A multi-source satellite data approach for modelling Lake Turkana water level: Calibration and validation using satellite altimetry data

Lake Turkana is one of the largest desert lakes in the world and is characterized by high degrees of inter- and intra-annual fluctuations. The hydrology and water balance of this lake have not been well understood due to its remote location and unavailability of reliable ground truth datasets. Managing surface water resources is a great challenge in areas where in-situ data are either limited or unavailable. In this study, multi-source satellite-driven data such as satellite-based rainfall estimates, modelled runoff, evapotranspiration, and a digital elevation dataset were used to model Lake Turkana water levels from 1998 to 2009. Due to the unavailability of reliable lake level data, an approach is presented to calibrate and validate the water balance model of Lake Turkana using a composite lake level product of TOPEX/Poseidon, Jason-1, and ENVISAT satellite altimetry data. Model validation results showed that the satellite-driven water balance model can satisfactorily capture the patterns and seasonal variations of the Lake Turkana water level fluctuations with a Pearson's correlation coefficient of 0.90 and a Nash-Sutcliffe Coefficient of Efficiency (NSCE) of 0.80 during the validation period (2004–2009). Model error estimates were within 10% of the natural variability of the lake. Our analysis indicated that fluctuations in Lake Turkana water levels are mainly driven by lake inflows and over-the-lake evaporation. Over-the-lake rainfall contributes only up to 30% of lake evaporative demand. During the modelling time period, Lake Turkana showed seasonal variations of 1–2 m. The lake level fluctuated in the range up to 4 m between the years 1998–2009. This study demonstrated the usefulness of satellite altimetry data to calibrate and validate the satellite-driven hydrological model for Lake Turkana without using any in-situ data. Furthermore, for Lake Turkana, we identified and outlined opportunities and challenges of using a calibrated satellite-driven water balance model for (i) quantitative assessment of the impact of basin developmental activities on lake levels and for (ii) forecasting lake level changes and their impact on fisheries. From this study, we suggest that globally available satellite altimetry data provide a unique opportunity for calibration and validation of hydrologic models in ungauged basins.

Lake Turkana↗

Hydrogeologic Framework in Three Drainage Basins in the New Jersey Pinelands, 2004-06

The U.S. Geological Survey, in cooperation with the New Jersey Pinelands Commission, began a multi-phase hydrologic investigation in 2004 to characterize the hydrologic system supporting the aquatic and wetland communities of the New Jersey Pinelands area (Pinelands). The Pinelands is an ecologically diverse area in the southern New Jersey Coastal Plain underlain by the Kirkwood-Cohansey aquifer system. The demand for ground water from this aquifer system is increasing as local development increases. To assess the effects of ground-water withdrawals on Pinelands stream and wetland water levels, three drainage basins were selected for detailed hydrologic assessments, including the Albertson Brook, McDonalds Branch and the Morses Mill Stream basins. Study areas were defined surrounding the three drainage basins to provide sub-regional hydrogeologic data for the ground-water flow modeling phase of this study. In the first phase of the hydrologic assessments, a database of hydrogeologic information and a hydrogeologic framework model for each of the three study areas were produced. These framework models, which illustrate typical hydrogeologic variations among different geographic subregions of the Pinelands, are the structural foundation for predictive ground-water flow models to be used in assessing the hydrologic effects of increased ground-water withdrawals. During 2004-05, a hydrogeologic database was compiled using existing and new geophysical and lithologic data including suites of geophysical logs collected at 7 locations during the drilling of 21 wells and one deep boring within the three study areas. In addition, 27 miles of ground-penetrating radar (GPR) surface geophysical data were collected and analyzed to determine the depth and extent of shallow clays in the general vicinity of the streams. On the basis of these data, the Kirkwood-Cohansey aquifer system was divided into 7 layers to construct a hydrogeologic framework model for each study area. These layers are defined by their predominant sediment textures as aquifers and leaky confining layers. The confining layer at the base of the Kirkwood-Cohansey aquifer system, depending on location, is defined as one of two distinct clays of the Kirkwood Formation. The framework models are described using hydrogeologic sections, maps of structure tops of layers, and thickness maps showing variations of sediment textures of the various model layers. The three framework models are similar in structure but unique to their respective study areas. The hydraulic conductivity of the Kirkwood-Cohansey aquifer system in the vicinity of the three study areas was determined from analysis of 16 slug tests and 136 well-performance tests. The mean values for hydraulic conductivity in the three study areas ranged from about 84 feet per day to 130 feet per day. With the exception of the basal confining layers, the variable and discontinuous nature of clay layers within the Kirkwood-Cohansey aquifer system was confirmed by the geophysical and lithologic records. Leaky confining layers and discontinuous clays are generally more common in the upper part of the aquifer system. Although the Kirkwood-Cohansey aquifer system generally has been considered a water-table aquifer in most areas, localized clays in the aquifer layers and the effectiveness of the leaky confining layers may act to impede the flow of ground water in varying amounts depending on the degree of confinement and the location, duration, and magnitude of the hydraulic stresses applied. Considerable variability exists in the different sediment textures. The extent to which this hydrogeologic variability can be characterized is constrained by the extent of the available data. Thus, the hydraulic properties of the modeled layers were estimated on the basis of available horizontal hydraulic conductivity data and the range of sediment textures estimated from geophysical and lithologic data.

Scientific Investigations Report↗

Statistical and descriptive summaries of water-resources data for the Cannonball River basin, North Dakota and South Dakota

Existing hydrologic data and information for the Cannonball River Basin were compiled by the U.S. Geological Survey in cooperation with the Bureau of Reclamation. This report presents a summary of surface-water quality and streamflow data, ground-water quality data, ground-water level data, water-use data, and other information compiled from the U.S. Geological Survey, Bureau of Reclamation, North Dakota Game and Fish Department, North Dakota Department of Health, North Dakota Parks and Recreation Department, North Dakota State Water Commission, and Standing Rock Sioux Tribe data bases. The data are summarized statistically or descriptively, depending on the amount or nature of the data.

Open-File Report↗

Baseline groundwater hydrology and water quality in and around Bluff, Utah

Southeastern Utah has a long history of oil and gas production. Two new hydrocarbon extraction wells have been proposed several miles northeast of the town of Bluff, Utah. In response to concern about the impacts of oil and gas extraction in the area on drinking-water quality, this study provides groundwater quality and hydrologic baseline data obtained before drilling the new hydrocarbon extraction wells. Data from future monitoring can be compared to these baseline water-quality data to identify changes in water quality. The quality of drinking water in Bluff is generally good, making changes in water quality more easily identifiable. Potential degradation of water quality from the proposed production wells could take hundreds to thousands of years to reach public-supply wells. Because of the limited water supply in this area, high-quality groundwater will continue to be an important resource into the foreseeable future.

Utah↗

Selected hydrologic data for Cache Valley, Utah and Idaho, 1969-91

This report contains hydrologic data collected in Cache Valley from 1969 to 1991. The report area is in north-central Utah and southeast Idaho, within the Basin and Range physiographic province described by Fenneman (1931), and includes about 660 square miles. Most of the data in this report were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Divisions of Water Resources and Water Rights. Some of the data collected before 1969 were previously published by McGreevy and Bjorklund (1970). The purpose of this report is to provide hydrologic data for use by the general public and by officials managing the area's water resources, and to supplement interpretive reports for the area. Tables 1 to 7 contain selected well, spring, and surface-water data. The numbering systems used in this report for hydrologic-data sites are illustrated in figure 1. Hydrologic-data sites are shown on plate 1. These data could not have been collected without the cooperation of local residents and officials of irrigation companies and municipalities, that permitted access to their wells, springs, and canals to measure water levels in wells and flow in springs and canals. The Idaho Department of Water Resources also provided valuable assistance and data.

Idaho, Utah↗

Hydrology of the coastal springs ground-water basin and adjacent parts of Pasco, Hernando, and Citrus Counties, Florida

The coastal springs in Pasco, Hernando, and Citrus Counties, Florida consist of three first-order magnitude springs and numerous smaller springs, which are points of substantial ground-water discharge from the Upper Floridan aquifer. Spring flow is proportional to the water-level altitude in the aquifer and is affected primarily by the magnitude and timing of rainfall. Ground-water levels in 206 Upper Floridan aquifer wells, and surface-water stage, flow, and specific conductance of water from springs at 10 gaging stations were measured to define the hydrologic variability (temporally and spatially) in the Coastal Springs Ground-Water Basin and adjacent parts of Pasco, Hernando, and Citrus Counties. Rainfall at 46 stations and ground-water withdrawals for three counties, were used to calculate water budgets, to evaluate long-term changes in hydrologic conditions, and to evaluate relations among the hydrologic components. Predictive equations to estimate daily spring flow were developed for eight gaging stations using regression techniques. Regression techniques included ordinary least squares and multiple linear regression techniques. The predictive equations indicate that ground-water levels in the Upper Floridan aquifer are directly related to spring flow. At tidally affected gaging stations, spring flow is inversely related to spring-pool altitude. The springs have similar seasonal flow patterns throughout the area. Water-budget analysis provided insight into the relative importance of the hydrologic components expected to influence spring flow. Four water budgets were constructed for small ground-water basins that form the Coastal Springs Ground-Water Basin. Rainfall averaged 55 inches per year and was the only source of inflow to the Basin. The pathways for outflow were evapotranspiration (34 inches per year), runoff by spring flow (8 inches per year), ground-water outflow from upward leakage (11 inches per year), and ground-water withdrawal (2 inches per year). Recharge (rainfall minus evapotranspiration) to the Upper Floridan aquifer consists of vertical leakage through the surficial deposits. Discharge is primarily through springs and diffuse upward leakage that maintains the extensive swamps along the Gulf of Mexico. The ground-water basins had slightly different partitioning of hydrologic components, reflecting variation among the regions. Trends in hydrologic data were identified using nonparametric statistical techniques to infer long-term changes in hydrologic conditions, and yielded mixed results. No trend in rainfall was detected during the past century. No trend in spring flow was detected in 1931-98. Although monotonic trends were not detected, rainfall patterns are naturally variable from month to month and year to year; this variability is reflected in ground-water levels and spring flows. A decreasing trend in ground-water levels was detected in the Weeki Wachee well (1966-98), but the trend was statistically weak. At current ground-water withdrawal rates, there is no discernible affect on ground-water levels and spring flows. Sporadic data records, lack of continuous data, and inconsistent periods of record among the hydrologic components impeded analysis of long-term changes to the hydrologic system and interrelations among components. The ongoing collection of hydrologic data from index sites could provide much needed information to assess the hydrologic factors affecting the quantity and quality of spring flow in the Coastal Springs Ground-Water Basin.

Water-Resources Investigations Report↗

The Everglades Depth Estimation Network (EDEN) surface-water interpolation model, version 3

The Everglades Depth Estimation Network (EDEN) is an integrated network of water-level gages, interpolation models that estimate daily water-level data at ungaged locations, and applications that generate derived hydrologic data across the freshwater part of the Greater Everglades landscape. Version 3 (V3) of the EDEN interpolation surface-water model is the most recent update, replacing the version 2 (V2) model released in 2011. The primary revision for the V3 model is the switch to the R programming language to create a more efficient and portable EDEN code relative to V2, without reliance on proprietary software. Using R, the interpolation script runs over 10 times faster and is more easily updated, for example, to accommodate changes in the gage network or to incorporate R software updates. Additional revisions made for the V3 model include updates to the interpolation model, the gage network, and groundwater-level estimations. The EDEN model domain in the Greater Everglades and Big Cypress National Preserve is divided into subdomains that are based on hydrologic boundaries. In the V3 model, the number of subdomains was increased from five to eight, which allows hydrologic boundaries, such as levees and canals, to be better represented in the interpolation scheme. Five pseudogages were added to constrain the water-level surface at subdomain boundaries. Changes made to the water-level gage network between the implementation of the V2 and V3 models are incorporated, and groundwater-level estimations are added, which are important information for hydrologic and ecological studies. Summary model performance statistics indicate similar accuracy in water-level surfaces generated by the V3 and V2 models, with a root mean square error of 4.78 centimeters for both interpolation models against independent water-level measurements. Providing stability and continuity for the EDEN user community, the V3 model closely replicates the V2 model, with a root mean square difference of 3.87 centimeters for interpolated surfaces from April 1, 2014, to March 31, 2018. The additional groundwater levels provide a realistic estimate of the saturated groundwater surface continuous with the surface-water surface for Water Conservation Areas 2A and 2B from 2000 to 2011. This continuous surface is a more accurate estimation of the spatial distribution of water in the hydrologic system than before, providing needed information for ecological studies in areas where depth to water table affects habitats. Development of the EDEN V3 model advances the tools available to scientists and resource managers for guiding large-scale field operations, describing hydrologic changes, and supporting biological and ecological assessments.

Florida↗

Framework for a U.S. Geological Survey hydrologic climate-response program in Maine

It is important to monitor hydrologic systems in the United States that could change dramatically over the short term as a result of climate change. Many ecological effects of climate change can be understood only if hydrologic data networks are in place. Because of its humid, temperate climate and its substantial annual snowpack, Maine’s seasonal water cycle is sensitive to air temperature changes (Hodgkins and others, 2003). Monitoring of relevant hydrologic data would provide important baseline information against which future climate change can be measured. A series of recent investigations by the U.S. Geological Survey (USGS) has documented changes in several components of the water cycle, including earlier snowmelt runoff in Maine during the last 30 to 40 years (Hodgkins and others, 2003), earlier lake- and river-ice breakups (Hodgkins and others, 2002; Hodgkins and others, 2005), and a denser and thinner late-winter snowpack (Hodgkins and Dudley, 2006). Snowmelt runoff timing was measured as the date, each year, by which half of the total winter-spring streamflow passed a streamflow-gaging station. Historical snowmelt runoff timing for the Piscataquis River in central Maine is shown in figure 1 as an example. Results of climate projections input to hydrologic models indicate that hydrologic trends, such as earlier spring snowmelt runoff, are expected to continue into the future (Hayhoe and others, 2007). These trends could affect species at the southern edge of their range in Maine, such as Atlantic salmon and Canada lynx, and may also affect availability of water for human use. This fact sheet describes the framework of a hydrologic climate-response program that would improve understanding of the effects of future climate change in Maine.

Maine↗

Hydrogeologic framework and groundwater/surface-water interactions of the upper Yakima River Basin, Kittitas County, central Washington

The hydrogeology, hydrology, and geochemistry of groundwater and surface water in the upper (western) 860 square miles of the Yakima River Basin in Kittitas County, Washington, were studied to evaluate the groundwater-flow system, occurrence and availability of groundwater, and the extent of groundwater/surface-water interactions. The study area ranged in altitude from 7,960 feet in its headwaters in the Cascade Range to 1,730 feet at the confluence of the Yakima River with Swauk Creek. A west-to-east precipitation gradient exists in the basin with the western, high-altitude headwaters of the basin receiving more than 100 inches of precipitation per year and the eastern, low-altitude part of the basin receiving about 20 inches of precipitation per year. From the early 20th century onward, reservoirs in the upper part of the basin (for example, Keechelus, Kachess, and Cle Elum Lakes) have been managed to store snowmelt for irrigation in the greater Yakima River Basin. Canals transport water from these reservoirs for irrigation in the study area; additional water use is met through groundwater withdrawals from wells and surface-water withdrawals from streams and rivers. Estimated groundwater use for domestic, commercial, and irrigation purposes is reported for the study area. A complex assemblage of sedimentary, metamorphic, and igneous bedrock underlies the study area. In a structural basin in the southeastern part of the study area, the bedrock is overlain by unconsolidated sediments of glacial and alluvial origin. Rocks and sediments were grouped into six hydrogeologic units based on their lithologic and hydraulic characteristics. A map of their extent was developed from previous geologic mapping and lithostratigraphic information from drillers’ logs. Water flows through interstitial space in unconsolidated sediments, but largely flows through fractures and other sources of secondary porosity in bedrock. Generalized groundwater-flow directions within the unconfined part of the aquifers in unconsolidated sediments indicate generalized groundwater movement toward the Yakima River and its tributaries and the outlet of the study area. Groundwater movement through fractures within the bedrock aquifers is complex and varies over spatial scales depending on the architecture of the fracture-flow system and its hydraulic properties. The complexity of the fracturedbedrock groundwater-flow system is supported by a wide range of groundwater ages determined from geochemical analyses of carbon-14, sulfur hexafluoride, and tritium in groundwater. These geochemical data also indicate that the shallow groundwater system is actively flushing with young, isotopically heavy groundwater, but isotopicallylight, Pleistocene-age groundwater with a geochemicallyevolved composition occurs at depth within the fracturedbedrock aquifers of upper Kittitas County. An eastward depletion of stable isotopes in groundwater is consistent with hydrologically separate subbasins. This suggests that groundwater that recharges in one subbasin is not generally available for withdrawal or discharge into surface-water features within other subbasins. Water budget components were calculated for 11 subbasins using a watershed model and varied based on the climate, land uses, and geology of the subbasin. Synoptic streamflow measurements made in August 2011 indicate that groundwater discharges into several tributaries of the Yakima River with several losses of streamflow measured where the streams exit bedrock uplands and flow over unconsolidated sediments. Profiles of stream temperature during late summer suggest cool groundwater inflow over discrete sections of streams. This groundwater/surfacewater connection is further supported by the stable-isotope composition of stream water, which reflects the local stableisotope composition of groundwater measured at some wells and springs. Collectively, these hydrogeologic, hydrologic, and geochemical data support a framework for evaluating the potential effects of future groundwater appropriations on senior surface-water and groundwater rights and streamflows. Although total pumping rates in upper Kittitas County of about 3.5 cubic feet per second are small relative to other components of the water budget, the magnitude, timing, and location of withdrawals may have important effects on the hydrologic system. The heterogeneous and variably fractured bedrock in the study area precluded a detailed evaluation of localized effects of pumping, but several generalizations about the groundwater and surface-water systems can be made. These generalizations include evidence for the continuity between the groundwater and surface-water system apparent from synoptic streamflow measurements, stream-temperature profiles, and stable-isotope data of groundwater and surface waters.

Washington↗

Water resources of the Kodiak-Shelikof subregion, south-central Alaska

Hydrologic data for the Kodiak-Shelikof subregion of south-central Alaska are summarized to provide a basis for planning water resources development, identifying water problems and evaluating existing water quality and availability. Average annual precipitation, measured at a few coastal locations in this maritime climatic zone, ranges from 23 to 127 inches. Mean annual runoff for the Kodiak Island group ranges from 4 to 8 cfs/sq mi. A maximum instantaneous runoff of 457 cfs/sq mi has been determined from a small basin on Kodiak Island. Lowest measured stream discharges range from no flow to 0.91 cfs/sq mi. Surface water is the primary source of water supplies for the city of Kodiak and other communities. The geology of the subregion is characterized by metamorphosed sedimentary and volcanic rocks with only a thin mantle of unconsolidated material. A few small, alluvium-filled coastal valleys offer the most favorable conditions for ground-water development, but moderate yields (50-100 gal/min) have been obtained from wells in fractured bedrock. Water in streams and lakes generally has a dissolved-solids concentration less than 60 mg/L, and the water varies from a calcium-bicarbonate type to a sodium-chloride type. The chemical composition of ground waters has a dilute calcium-bicarbonate type in unconsolidated materials and a sodium-bicarbonate type in bedrock. The dissolved solids in the groundwater ranges from 170 to 250 mg/L.

Alaska↗

Current water resources activities in Alabama, fiscal year 1986

The purpose of this report is to describe the current (as of 1986) water resources activities of the U.S. Geological Survey in Alabama. The responsibilities and objectives of the Survey; organization of the Alabama District; sources of funding; current projects; hydrologic data program; and a selected bibliography of hydrologic reports are presented. Water resources projects are undertaken usually at the request of and with partial funding from another agency, provided: they are high priority problems and generally identified to fall within the mission of the Water Resources Division and they are consistent with the Program Management Plan developed by the Water Resources Division in Alabama to meet the long range plan for hydrologic data in the State. (USGS)

Open-File Report↗

Ground-water favorability and surficial geology of the Windham-Freeport area, Maine

This report is one of a series describing the geologic and hydrologic conditions governing the occurrence of ground water in Maine. It is a product of the cooperative program of water-resources investigations between the U.S. Geological Survey and the State of Maine Public Utilities Commission. (See index map.) These reports are intended to provide information for the use of those engaged in water- or land-resources planning or development, and particularly for those wishing to develop water supplies large enough for public, industrial, or commercial use. The magnitude of yields that might be obtained from properly located and constructed wells is indicated by the map showing surficial geology and ground-water favorability (figs. 2, 2a). This map gives a generalized interpretation of observed geologic and hydrologic data; it provides a basis for guiding detailed exploration for ground water but does not eliminate the need for such exploration.

Maine↗

Ground-water basic data for Griggs and Steele Counties, North Dakota

The objectives of the hydrologic investigation in Griggs and Steele Counties, N. Dak. (fig. 1) were to: (1) determine the location, extent, and nature of the major aquifers; (2) evaluate the occurrence and movement of ground water, including recharge and discharge; (3) estimate the quantities of water stored in the aquifers; (4) estimate the potential yields of wells tapping the major aquifers; and (5) determine the chemical quality of the ground water.

North Dakota↗