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At least 973 records · Page 54Linked to original sources
USGS2014

Base of principal aquifer for parts of the North Platte, South Platte, and Twin Platte Natural Resources Districts, western Nebraska

Water resources in the North and South Platte River valleys of Nebraska, including the valley of Lodgepole Creek, are critical to the social and economic health of the area, and for the recovery of threatened and endangered species in the Platte River Basin. Groundwater and surface water are heavily used resources, and uses are regulated in the study area. Irrigation is the dominant water use and, in most instances, is supplied by both groundwater and surface-water sources. The U.S. Geological Survey and its partners have collaborated to use airborne geophysical surveys for areas of the North and South Platte River valleys including the valley of Lodgepole Creek in western Nebraska. The objective of the surveys was to map the aquifers and underlying bedrock topography of selected areas to help improve the understanding of groundwater–surface-water relations to guide water-management decisions. This project was a cooperative study involving the North Platte Natural Resources District, the South Platte Natural Resources District, the Twin Platte Natural Resources District, the Conservation and Survey Division of the University of Nebraska-Lincoln, and the Nebraska Environmental Trust. This report presents the interpreted base-of-aquifer surface for part of the area consisting of the North Platte Natural Resources District, the South Platte Natural Resources District, and the Twin Platte Natural Resources District. The interpretations presented herein build on work done by previous researchers from 2008 to 2009 by incorporating additional airborne electromagnetic survey data collected in 2010 and additional test holes from separate, related studies. To make the airborne electromagnetic data useful, numerical inversion was used to convert the measured data into a depth-dependent subsurface resistivity model. An interpretation of the elevation and configuration of the base of aquifer was completed in a geographic information system that provided x, y, and z coordinates. The process of interpretation involved manually picking locations (base-of-aquifer elevations) on the displayed airborne electromagnetic-derived resistivity profile by the project geophysicist, hydrologist, and geologist. These locations, or picks, of the base-of-aquifer elevation (typically the top of the Brule Formation of the White River Group) were then stored in a georeferenced database. The pick was made by comparing the inverted airborne electromagnetic-derived resistivity profile to the lithologic descriptions and borehole geophysical logs from nearby test holes. The database of interpretive picks of the base-of-aquifer elevation was used to create primary input for interpolating the new base-of-aquifer contours. The automatically generated contours were manually adjusted based on the interpreted location of paleovalleys eroded into the base-of-aquifer surface and associated bedrock highs, many of which were unmapped before this study. When contours are overlain by the water-table surface, the saturated thickness of the aquifer can be computed, which allows an estimate of total water in storage. The contours of the base-of-aquifer surface presented in this report may be used as the lower boundary layer in existing and future groundwater-flow models. The integration of geophysical data into the contouring process facilitated a more continuous and spatially comprehensive view of the hydrogeologic framework.

Nebraska↗
USGS2000

Assessment of volatile organic compounds in surface water at West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 1999

The U.S. Geological Survey (USGS) collected 13 surface-water samples and 3 replicates from 5 sites in the West Branch Canal Creek area at Aberdeen Proving Ground from February through August 1999, as a part of an investigation of ground-water contamination and natural attenuation processes. The samples were analyzed for volatile organic compounds, including trichloroethylene, 1,1,2,2-tetrachloroethane, carbon tetrachloride, and chloroform, which are the four major contaminants that were detected in ground water in the Canal Creek area in earlier USGS studies. Field blanks were collected during the sampling period to assess sample bias. Field replicates were used to assess sample variability, which was expressed as relative percent difference. The mean variability of the surface-water replicate analyses was larger (35.4 percent) than the mean variability of ground-water replicate analyses (14.6 percent) determined for West Branch Canal Creek from 1995 through 1996. The higher variability in surface-water analyses is probably due to heterogeneities in the composition of the surface water rather than differences in sampling or analytical procedures. The most frequently detected volatile organic compound was 1,1,2,2- tetrachloroethane, which was detected in every sample and in two of the replicates. The surface-water contamination is likely the result of cross-media transfer of contaminants from the ground water and sediments along the West Branch Canal Creek. The full extent of surface-water contamination in West Branch Canal Creek and the locations of probable contaminant sources cannot be determined from this limited set of data. Tidal mixing, creek flow patterns, and potential effects of a drought that occurred during the sampling period also complicate the evaluation of surface-water contamination.

Open-File Report↗
USGS1980

Hydrology and model study of the proposed Prosperity Reservoir, Center Creek Basin, southwestern Missouri

A dam and reservoir have been proposed for construction on Center Creek, Jasper County, in southwestern Missouri. Ground-water levels in the hills adjacent to the reservoir will rise when the impoundment is completed. One of the problems is that the proposed site of Prosperity Reservoir is a few miles upstream from the lead-zinc mining area known as the Oronogo-Duenweg belt. In this belt transmissivities are variable but appear to be higher than they are in the immediate area of the reservoir. Grove Creek lies down-gradient from the reservoir area and separates it from the mining belt. A model study indicates that inflow from the proposed reservoir to the water table could cause water level rises varying from about 20 feet near the reservoir to 0.5 to 1.0 foot in the southern part of Grove Creek drainage basin. These rises will cause significant changes to the natural ground-water flow system. Increased ground-water elevations in the reservoir area could result in increased ground-water gradients and discharge to Grove and Center Creeks. The increase in ground-water discharge to Grove Creek, and in turn Center Creek, will have the beneficial effect of diluting mine-water discharge from the Oronogo-Duenweg belt during periods of low flow. However, if Grove Creek does not act as an effective drain and if conduits extend beneath Grove Creek to transfer the increased water available to the Oronogo-Duenweg belt, the flow regimen could change in the mining belt west of Grove Creek increasing mine-water discharge to Center Creek downstream from the reservoir. Bedrock in the area is Mississippian limestone, the deeply solutioned formation that contained the ore deposits. The limestone in the mining district was greatly altered by solution prior to ore deposition while the limestone in the area of the reservoir was altered less. The extent of the alteration is related to the aquifer characteristics in that high and low values of transmissivity and storage coefficient correspond to greatly altered brecciated rocks in the mining district and less altered, less brecciated rocks in the reservoir area, respectively. The authors suggest that an ancestral east-flowing White River drained the area about Joplin in Late Mississippian time. This is based on the configuration of the contact between Meramecian and Osagean rocks of Mississippian age. A high topographic area existed in the region about Joplin in which the water table stood 200 feet below the land surface when sinkholes and caverns of that depth were formed. The large number of Pennsylvanian-filled sinkholes in the Joplin area and the smaller number to the east suggest a higher land surface to the west than that to the east. The distribution of paleokarst sinkholes supports the conclusion based on the configuration of the Meramecian-Osagean contact.

Missouri↗
USGS1983

Reconnaissance of the quality of surface water in the Weber River basin, Utah

This report on the reconnaissance of surface-water quality in the Weber River basin was prepared by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights. The purposes of the reconnaissance were: (1) To obtain information on the general inorganic chemical characteristics of the surface water throughout the Weber River basin and, (2) to determine some of the effects of the natural environment and of present water use on these chemical characteristics. The reconnaissance was limited in scope and did not include intensive study of the effects of municipal sewage, irrigation, industry, or mining on water quality. The principal objective was to define the general water-quality characteristics of streams in the basin. A secondary objective was to define specific problem areas or stream reaches.

Utah↗
USGS1999

Hydrology of the coastal lowlands aquifer system in parts of Alabama, Florida, Louisiana, and Mississippi

Existing data on water levels, water use, water quality, and aquifer properties were used to construct a multilayer digital model to simulate flow in the aquifer system. The report describes the geohydrologic framework of the aquifer system, and the development, calibration, and sensitivity analysis of the ground-water-flow model, but it is primarily focused on the results of the simulations that show the natural flow of ground water throughout the regional aquifer system and the changes from the natural flow caused by development of ground-water supplies.

Alabama, Florida, Louisiana, Mississippi↗
USGS2012

Hydrologic effects on water level changes associated with episodic fault creep near Parkfield, California

As part of the Parkfield, California, earthquake prediction experiment, water level is monitored in a well 460 m from the main trace of the San Andreas fault on Middle Mountain, in the preparation zone of the anticipated Parkfield earthquake. The well configuration allows water level to be monitored in two fluid reservoirs at depths of 85 and 250 m below land surface. During 1987, water level changes were recorded during 12 of the 18 episodes of accelerated fault creep detected by a creep meter spanning the fault trace 750 m northwest of the well. The creep-related water level changes in the shallow reservoir have durations of less than 1 day, whereas in the deeper reservoir the changes persist for as long as 2 months. These data suggest that the transient nature of the water level changes in the shallow interval is due to vertical flow to the water table and is not evidence that creep events propagate past the well. Phase leads of earth tidal constituents in the water level data from the shallow interval relative to the same constituents in the local volume strain tide support the interpretation of significant flow to the water table at periods of 1 day or less. The form of the water level changes in the deep interval is affected by horizontal flow to the well bore. This effect can be removed from the water level records using a theoretical response curve constrained by the phases of earth tidal constituents in the deep interval relative to the local volume strain tide. For the events where the signal in the shallow interval has been large enough to measure, the sizes of the simultaneous water level changes in the two reservoirs are consistent with the same amounts of volume strain occurring at both depths.

Journal of Geophysical Research Solid Earth↗
USGS1988

U.S. Geological Survey ground-water studies in Oregon

The use of groundwater in Oregon is expected to increase owing to continued population growth and to surface water supplies that are inadequate to meet present or future demand. The major groundwater issues in Oregon are: conjunctive use of surface and groundwater; contamination from hazardous wastes, leakage from underground gasoline and diesel tanks, naturally occurring brackish water, and high concentrations of dissolved iron; groundwater availability; and Indian water rights. Before 1987, the Oregon Water Resources Department, in cooperation with the U.S. Geological Survey (USGS), maintained a network of about 400 observation wells in Oregon to monitor fluctuations in groundwater levels. Water levels currently are measured cooperatively only in active project areas. The USGS has conducted more than 120 hydrologic investigations in Oregon. During fiscal year 1987, the USGS entered into cooperative agreements with 23 local, State, and Federal agencies to conduct hydrologic investigations in Oregon; six investigations included quantitative studies of groundwater. Examples of these groundwater studies are: groundwater hydrology of the Portland basin; groundwater hydrology in the Umatilla Plateau; and iron geochemistry of a sand dune aquifer near Coos Bay. (Lantz-PTT)

Open-File Report↗
USGS1984

Distribution and source of barium in ground water at Cattaraugus Indian Reservation, southwestern New York

High concentrations of dissolved barium have been found in ground water from bedrock wells on the Seneca Nation of Indians Reservation on Cattaraugus Creek in southwestern New York. Concentrations in 1982 were as high as 23.0 milligrams per liter , the highest found reported from any natural ground-water system in the world. The highest concentrations are in a bedrock aquifer and in small lenses of saturated gravel between bedrock and the overlying till. The bedrock aquifer is partly confined by silt, clay, and till. The high barium concentrations are attributed to dissolution of the mineral barite (BaSO4), which is present in the bedrock and possibly in overlying silt, clay, or till. The dissolution of barite seems to be controlled by action of sulfate-reducing bacteria, which alter the BaSO4 equilibrium by removing sulfate ions and permitting additional barite to dissolve. Ground water from the surficial, unconsolidated deposits and surface water in streams contain little or no barium. Because barium is chemically similar to calcium, it probably could be removed by cation exchange or treatments similar to those used for water softening. (USGS)

Water-Resources Investigations Report↗
USGS2025

Characterization of DOC in riparian wetland pore water and its interference in stable water isotope analysis of δ2H and δ18O

Wetlands play an important role in carbon retention, which is greatly dependent on hydrological conditions. Therefore, the interest in wetland hydrology has increased over recent decades. In wetland hydrology, stable water isotopes ( δ 2 H, δ 18 O) have found increasing use, as laser-based instruments have become readily available and allow for faster analysis and lower costs. However, the use of laser-based determinations of stable hydrogen and oxygen isotopes in wetland pore waters might be challenging because of dissolved organic carbon (DOC), especially as wetland pore waters often contain elevated DOC concentrations. To study the potential interference of DOC on laser-based stable water isotopes determination, we determined concentration, fluorescence and absorbance characteristics of DOC in pore waters collected from six restored and six near-natural riparian wetlands. The water samples’ δ 2 H and δ 18 O values were determined by two laser absorption spectrometers (LAS) and, for reference, in parallel by dual-inlet isotope-ratio mass spectrometry (DI-IRMS). The two LAS methods showed significant deviations from the DI-IRMS-determinations. Variations in the specific UV absorbance index (SUVA 254 , the quotient of the absorbance at 254 nm and the DOC concentration), which indicates the aromaticity of the DOC, partially accounted for interference for δ 2 H measurements. Elevated SUVA 254 index values were especially linked to restored wetlands. Studies that investigate pore waters with high DOC aromaticity but where the DOC is not characterized, and which require a high accuracy of the δ 2 H-values for interpretation of the hydrological system, may be severely affected by DOC interference.

Journal of Hydrology↗
USGS2010

Water vapour correction of the daily 1 km AVHRR global land dataset: Part I validation and use of the Water Vapour input field

An atmospheric correction algorithm developed for the 1 km Advanced Very High Resolution Radiometer (AVHRR) global land dataset was modified to include a near real-time total column water vapour data input field to account for the natural variability of atmospheric water vapour. The real-time data input field used for this study is the Television and Infrared Observational Satellite (TIROS) Operational Vertical Sounder (TOVS) Pathfinder A global total column water vapour dataset. It was validated prior to its use in the AVHRR atmospheric correction process using two North American AVHRR scenes, namely 13 June and 28 November 1996. The validation results are consistent with those reported by others and entail a comparison between TOVS, radiosonde, experimental sounding, microwave radiometer, and data from a hand-held sunphotometer. The use of this data layer as input to the AVHRR atmospheric correction process is discussed.

International Journal of Remote Sensing↗
USGS2001

Balancing Ground-Water Withdrawals and Streamflow in the Hunt-Annaquatucket-Pettaquamscutt Basin, Rhode Island

Ground water withdrawn for water supply reduces streamflow in the Hunt-Annaquatucket-Pettaquamscutt Basin in Rhode Island. These reductions may adversely affect aquatic habitats. A hydrologic model was prepared by the U.S. Geological Survey in cooperation with the Rhode Island Water Resources Board, Town of North Kingstown, Rhode Island Department of Environmental Management, and Rhode Island Economic Development Corporation to aid water-resource planning in the basin. Results of the model provide information that helps water suppliers and natural-resource managers evaluate strategies for balancing ground-water development and streamflow reductions in the basin.

Fact Sheet↗
USGS2007

Ground-Water Nutrient Flux to Coastal Waters and Numerical Simulation of Wastewater Injection at Kihei, Maui, Hawaii

Water sampling and numerical modeling were used to estimate ground-water nutrient fluxes in the Kihei area of Maui, where growth of macroalgae (seaweed) on coral reefs raises ecologic concerns and accumulation on beaches has caused odor and removal problems. Fluxes and model results are highly approximate, first-order estimates because very few wells were sampled and there are few field data to constrain model calibration. Ground-water recharge was estimated to be 22.6 Mgal/d (million gallons per day) within a 73-square-mile area having a coastline length of 8 miles or 13 km (kilometers). Nearly all of the recharge discharges at the coast because ground-water withdrawals are small. Another 3.0 Mgal/d of tertiary-treated wastewater effluent is injected into the regional aquifer at a County treatment plant midway along the coast and about a mile from shore. The injection plume is 0.93 miles wide (1.5 km) at the shore, as estimated from a three-dimensional numerical ground-water model. Wastewater injected beneath the brackish ground-water lens rises buoyantly and spreads out at the top of the lens, diverting and mixing with ambient ground water. Ground water discharging from the core of the injection plume is less than 5 years old and is about 60 percent effluent at the shore, according to the model. Dissolved nitrogen and phosphorus concentrations in treated effluent were 7.33 and 1.72 milligrams per liter, roughly 6 and 26 times background concentrations at an upgradient well. Background nitrogen and phosphorus fluxes carried by ground water are 7.7 and 0.44 kg/d-km (kilograms per day per kilometer of coast). Injected wastewater fluxes distributed across the plume width are 55 and 13 kg/d-km nitrogen and phosphorus, roughly 7 and 30 times background flux. However, not all of the injected load reaches coastal waters because nutrients are naturally attenuated in the oxygen-depleted effluent plume. Water from a downgradient well reflects this attenuation and provides a more conservative estimate of injection flux approaching the shore: 27 and 1.5 kg/d-km nitrogen and phosphorus, roughly one-half and one-ninth the injection-source estimates, and 3.5 and 3.4 times background flux. Effluent has 8 O and 2 H stable-isotope signatures that are distinct from local ground water, as well as 15 N and 11 B signatures diagnostic of domestic waste and laundry detergents, respectively. Pharmaceuticals and organic wastewater compounds also were present in effluent and the downgradient well. These isotopes and chemicals served as wastewater tracers in Kihei ground water and may be useful tracers in nearshore marine waters and aquifers elsewhere in Hawaii.

Scientific Investigations Report↗
USGS2001

Ground-water quality in the southeastern Sacramento Valley aquifer, California, 1996

In 1996, the U.S. Geological Survey sampled 29 domestic wells and 2 monitoring wells in the southeastern Sacramento Valley as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. This area, designated as the NAWQA Sacramento subunit study area, was chosen because it had the largest amount of ground-water use in the Sacramento River Basin. The Sacramento subunit study area is about 4,400 square kilometers and includes intense agricultural and urban development. The wells sampled ranged from 14.9 to 79.2 meters deep. Ground-water samples from 31 wells were analyzed for 6 field measurements, 14 inorganic constituents, 6 nutrient constituents, organic carbon, 86 pesticides, 87 volatile organic compounds, tritium (hydrogen-3), radon-222, deuterium (hydrogen-2), and oxygen-18. Nitrate levels were lower than the 2000 drinking-water standards in all but one well, but many detections were in the range that indicated an effect by human activities on ground-water quality. Radon was detected in all wells, and was measured at levels above the proposed Federal 2000 maximum contaminant level in 90 percent of the wells. Five pesticides and one pesticide degradation product were detected in ground-water samples and concentrations were below 2000 drinking-water standards. All pesticides detected during this study have been used in the Sacramento Valley. Thirteen volatile organic compounds were detected in ground water. One detection of trichloroethene was above Federal 2000 drinking-water standards, and another, tetrachloromethane, was above California 1997 drinking-water standards; both occurred in a well that had eight volatile organic compound detections and is near a known source of ground-water contamination. Pesticides and volatile organic compounds were detected in agricultural and urban areas; both pesticides and volatile organic compounds were detected at a higher frequency in urban wells. Ground-water chemistry indicates that natural processes and human activities are affecting ground-water quality in the upper part of the southeastern Sacramento Valley aquifer. The factors identified as having an influence on ground-water quality were redox condition in the aquifer, depth within the aquifer, and land use overlying the aquifer. Nitrate concentrations showed a statistical correlation with each of these factors. Detections of pesticides and volatile organic compounds were too few to compare concentrations with the various factors, but the types of synthetic compounds detected were consistent with the sur-rounding land use. Sixty-one percent of the wells sampled in this study showed the effect of human activities on ground-water quality in the form of a nitrate concentration over 3 milligrams per liter or a detection of a pesticide or volatile organic compound. In general, the water quality in the southeastern Sacramento Valley aquifer was found suitable for most uses.

California↗
USGS1983

Evaluation of the San Dieguito, San Elijo, and San Pasqual hydrologic subareas for reclaimed water use, San Diego County, California

A study was made to determine the suitability of three small hydrologic subareas in San Diego County, California, for reuse of municipal wastewater. Ground-water quality has been impacted by agricultural water use, imported water use, changes in natural recharge patterns, seawater intrusion, and intrusion of ground water from surrounding marine sediments; therefore, ground water is of limited value as a water-supply source. Reclaimed water use is feasible and expected to improve ground-water quality, creating a new source of water for agricultural use.

Calilfornia↗
USGS1996

Hydrogeology and ground-water quality of glacial-drift aquifers, Leech Lake Indian Reservation, north-central Minnesota

Among the duties of the water managers of the Leech Lake Indian Reservation in north-central Minnesota are the development and protection of the water resources of the Reservation. The U.S. Geological Survey, in cooperation with the Leech Lake Indian Reservation Business Committee, conducted a three and one half-year study (1988-91) of the ground-water resources of the Leech Lake Indian Reservation. The objectives of this study were to describe the availability and quality of ground water contained in glacial-drift aquifers underlying the Reservation. Aquifers and confining units are present throughout the entire thickness of the glacial drift in the study area, which includes the Leech Lake Indian Reservation and adjacent parts of Beltrami, Hubbard, Itasca, and Cass Counties in north-central Minnesota, an area of approximately 2,145 square miles. An unconfined aquifer underlies most of the central and north-central parts of the study area. The saturated thickness of the aquifer ranges from 0 to about 105 feet. Horizontal hydraulic conductivity, estimated from 19 slug tests, ranges from 0.6 to 31 feet per day. The transmissivity of the aquifer ranges from 19 to more than 20,000 feet squared per day and is greatest in an area from west of Cass Lake to Lake Winnibigoshish. Theoretical maximum well yields range from less than 10 to about 2,000 gallons per minute. The unconfined and uppermost confined aquifers are physically and hydraulically separated by a fine-grained confining unit, consisting of till or lake deposits, that ranges in thickness from 3 to 254 feet. The thickness of the uppermost confined aquifer ranges from 5 to about 53 feet. On the basis of specific-capacity data, the transmissivity of the aquifer ranges from less than 100 feet squared per day in the northeastern and southeastern parts of the study area to about 21,000 feet squared per day near Cass Lake. Theoretical maximum well yields range from less than 10 to about 2,600 gallons per minute. Recharge to the ground-water system is predominantly from precipitation that infiltrates to the saturated zone. An analysis of four hydrographs for observation wells screened in the unconfined aquifer indicated spring recharge amounts during 1989 of 1-4 inches. Discharge from the ground-water system occurs by leakage to streams, lakes, and wetlands, evapotranspiration, withdrawals by wells, and underflow to the southeast within the Mississippi River Valley. Streamflow measurements indicate that ground-water discharge to the Mississippi River is greater in the western part of the study area between Cass Lake and Lake Winnibigoshish than in the eastern part downstream from Lake Winnibigoshish. The general regional direction of ground-water flow in the unconfined and uppermost confined aquifers is to the east and southeast. Ground-water flow is also toward the Mississippi River and the three large lakes in the study area, Lake Winnibigoshish and Cass and Leech Lakes. Water moves through the ground-water system predominantly horizontally in the aquifers, whereas vertical components of flow are significant in confining units. Downward leakage of water occurs in highland areas where ground water flows downward from overlying till to the uppermost confined aquifer. Water moves vertically upward from deep to shallow aquifers in areas of regional discharge, the Mississippi River, Cass Lake, Lake Winnibigoshish. and Leech Lake. Waters from both the unconfined and uppermost confined aquifers generally are suitable for domestic consumption, crop irrigation, and most other uses. Concentrations of iron and manganese in water from both aquifers frequently exceed levels that may impart an undesirable taste or odor to water. Calcium and bicarbonate are the predominant ions in water from both the unconfined and uppermost confined aquifers. Water from both the unconfined and uppermost confined aquifers is hard to very hard, averaging 187 and 247 milligrams per liter as calcium carbonate, respectively. Differences in the mean concentrations of constituents in waters from the unconfined and uppermost confined aquifers vary. The mean concentrations of chloride, manganese, dissolved organic carbon, sulfate, and dissolved iron were greater for water from the unconfined aquifer than for water from the uppermost confined aquifer. Conversely, the mean concentrations of calcium, potassium, silica, sodium, fluoride, and boron were greater for water from the uppermost confined aquifer than for water from the unconfined aquifer. These higher concentrations of naturally occurring constituents in waters from the uppermost confined aquifer may occur because of the longer flow paths and longer residence times of water in the uppermost confined aquifer as compared to the unconfined aquifer. Nutrients include nitrogen and phosphorus species. The mean concentrations of dissolved nitrogen (NO 2 + NO 3 , dissolved) and total phosphorus were about 5 and 1.5 times greater for water from the unconfined aquifer than for water from the uppermost confined aquifer, respectively. None of the water samples had concentrations of dissolved nitrogen greater than the maximum contaminant level established by the U.S. Environmental Protection Agency (10 milligrams per liter) and only one water sample had a concentration greater than 3 milligrams per liter. Water collected from wells completed in the unconfined aquifer in residential and recreational land-use areas had concentrations of arsenic, cadmium, chromium, copper, lead, mercury, and cyanide equal to or less than 6 micrograms per liter. Concentrations of organic-acid herbicides in water from three wells screened in the unconfined aquifer in managed-forest land-use areas were all below detection levels. Concentrations of U.S. Environmental Protection Agency priority pollutants in water from three wells screened in the unconfined aquifer and from one well screened in the uppermost confined aquifer were also all below detection levels.

Minnesota↗
USGS1995

Changes in the volume of water in the Mississippi River alluvial aquifer in the Delta, northwestern Mississippi, 1980-94

The U.S. Geological Survey, in cooperation with the Mississippi Department of Environmental Quality, Office of Land and Water Resources, and the Natural Resources Conservation Service, estimated the volumetric changes of water in the Mississippi River alluvial aquifer in northwestern Mississippi from 1980 through 1994. Volumetric changes of water in the alluvial aquifer were estimated for the entire Delta and for five selected areas within the Delta. The volume of water per square mile in the alluvial aquifer in the Delta changed from 17,886 acre-feet during fall 1980 to 17,719 acre-feet during fall 1994, a decrease in volume per square mile of 167 acre-feet. The minimum volume of water per square mile in the alluvial aquifer in the Delta during 1980-94 was 17,640 acre-feet during fall 1988. Of five selected areas within the Delta, an area near Cleveland in Bolivar County had the greatest change in volume of water in the alluvial aquifer. During fall 1980 this area had 20,790 acre-feet of water per square mile in the aquifer; by fall 1994, the volume had decreased to 19,947 acre-feet of water per square mile. An area located in the vicinity of the Sunflower-Leflore County line has within its boundaries a large cone of depression in the potentiometric surface of the alluvial aquifer. The volume of water per square mile in this area decreased from 17,857 acre-feet during fall 1980 to 17,075 acre-feet during fall 1994.

Mississippi↗
USGS2014

Groundwater-surface water relations in the Fox River watershed: insights from exploratory studies in Illinois and Wisconsin

Exploratory studies were conducted at sites bordering the Fox River in Waukesha, Wisconsin, during 2010 and McHenry, Illinois, during 2011–13. The objectives of the studies were to assess strategies for the study of and insights into the potential for directly connected groundwater and surface-water systems with natural groundwater discharge to streams diverted and (or) streamflow induced (captured) by nearby production-well withdrawals. Several collection efforts of about 2 weeks or less provided information and data on site geology, groundwater and surface-water levels, hydraulic gradients, water-temperature and stream-seepage patterns, and water chemistry including stables isotopes. Overview information is presented for the Waukesha study, and selected data and preliminary findings are presented for the McHenry study.

Illinois;Wisconsin↗
USGS2018

Current research in land, water, and agroecosystems: ASABE journals 2017 year in review

This article highlights current research into land and water resources, agroecosystems, and agricultural production systems published by the Natural Resources and Environmental Systems (NRES) community of ASABE journals (Transactions of the ASABE and Applied Engineering in Agriculture) in 2017. This article reviews the context, scope, and key results of the published articles and perhaps more importantly recommends areas for increased research attention. Experimental and modeling advances were described in hydrology, agroecosystems, climate-change effects, soil erosion, irrigation, drainage, forest resources, livestock systems, natural treatment systems, international water issues, and water quality topic areas. Three special collections were published (International Watershed Technology, Crop Modeling to Optimize Water Use, and Advances in Drainage). Other focal areas included 14 articles relating to livestock waste management, 13 concerning irrigated agricultural systems, 8 addressing climate change effects on land and water resources, and 16 on various aspects of soil erosion measurement and modeling. Building on the articles reviewed from 2017 and toward a vision of future agroecosystems research, the NRES community of ASABE journals strives to grow its role in making new knowledge accessible to sustain agricultural and natural systems in a changing world. In this vane, recommendations for future research direction are discussed with an emphasis on increased application of remote sensing data to agroecosystems research, improved assessment of agroecosystem resiliency and vulnerability to land and climate change, development of integrated models of agroecosystem services, meeting stubborn water management challenges in agricultural production systems, and focusing on publishing fully reproducible model results.

Transactions of the ASABE↗