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At least 901 records · Page 50Linked to original sources
USGS2020

Potomac tributary report: A summary of trends in tidal water quality and associated factors

The Potomac Tributary Report summarizes change over time in a suite of monitored tidal water quality parameters and associated potential drivers of those trends for the time period 1985 – 2018, and provides a brief description of the current state of knowledge explaining these observed changes. Water quality parameters described include surface total nitrogen (TN), surface total phosphorus (TP), spring and summer surface chlorophyll a, summer bottom dissolved oxygen (DO) concentrations, and Secchi disk depth (a measure of water clarity). Results for annual surface water temperature, bottom TP, bottom TN, surface ortho-phosphate (PO4), surface dissolved inorganic nitrogen (DIN), surface total suspended solids (TSS), and summer surface DO concentrations are provided in an Appendix. Drivers discussed include physiographic watershed characteristics, changes in N, P, and sediment loads from the watershed to tidal waters, expected effects of changing land use, and implementation of nutrient management and natural resource conservation practices. Factors internal to estuarine waters that also play a role as drivers are described including biogeochemical processes, physical forces such as wind-driven mixing of the water column, and biological factors such as phytoplankton biomass and the presence of submersed aquatic vegetation. Total nutrient concentrations have been decreasing at most stations in the Potomac River over the long-term, with improvements persisting in the last 10 years as well. These trends follow from the decreasing discharge from TN and TP sources in the watershed. The TP source reductions are not as apparent in the direct loads to the river, which may be part of the reason that tidal nutrient concentrations are not decreasing at as many stations in the short-term as the long-term. While degrading chlorophyll a and Secchi depth trends at several Potomac monitoring stations are concerning, recent improvements in summer oxygen concentrations are promising. The findings that chlorophyll a concentrations in the lower Potomac have either leveled out or improved may suggest a smaller amount of phytoplankton biomass available to fuel summer oxygen depletion. The responses of chlorophyll a, Secchi depth, and bottom DO are mixed in the Potomac tidal waters, but there are multiple possible reasons for this lag in response. Continuing to track water quality response and investigating these possibilities are important steps to understanding water quality patterns and changes in the Potomac River.

Pennsylvania, Virginia, West Viginia↗
USGS2021

Natural and anthropogenic geochemical tracers to investigate residence times and groundwater–surface-water interactions in an urban alluvial aquifer

A multi-component geochemical dataset was collected from groundwater and surface-water bodies associated with the urban Fountain Creek alluvial aquifer, Colorado, USA, to facilitate analysis of recharge sources, geochemical interactions, and groundwater-residence times. Results indicate that groundwater can be separated into three distinct geochemical zones based on location within the flow system and proximity to surface water, and these zones can be used to infer sources of recharge and groundwater movement through the aquifer. Rare-earth-element concentrations and detections of wastewater-indicator compounds indicate the presence of effluent from wastewater-treatment plants in both groundwater and surface water. Effluent presence in groundwater indicates that streams in the area lose to groundwater in some seasons and are a source of focused groundwater recharge. Distributions of pharmaceuticals and wastewater-indicator compounds also inform an understanding of groundwater–surface-water interactions. Noble-gas isotopes corroborate rare-earth-element data in indicating geochemical evolution within the aquifer from recharge area to discharge area and qualitatively indicate variable groundwater-residence times and mixing with pre-modern groundwater. Quantitative groundwater-residence times calculated from 3 H/ 3 He, SF 6 , and lumped-parameter modeling generally are less than 20 years, but the presence of mixing with older groundwater of an unknown age is also indicated at selected locations. Future investigations would benefit by including groundwater-age tracers suited to quantification of mixing for both young (years to decades) and old (centuries and millennia) groundwater. This multi-faceted analysis facilitated development of a conceptual model for the investigated groundwater-flow system and illustrates the application of an encompassing suite of analytes in exploring hydrologic and geochemical interactions in complex systems.

Colorado↗
USGS1988

A seismic-stratigraphic investigation of the Madison and associated aquifers; application to ground-water exploration, Powder River basin, Montana-Wyoming

This seismic-stratigraphic investigation is part of a larger 5-year project the "Madison Project" undertaken by the Water Resources Division of the U.S. Geological Survey to study the hydrology of the Madison and associated aquifers. The objectives and methods of investigation of the Madison Project are described by the U.S. Geological Survey (1975).

Montana, Wyoming↗
USGS2015

Water-quality conditions and suspended-sediment transport in the Wilson and Trask Rivers, northwestern Oregon, water years 2012–14

In October 2011, the U.S. Geological Survey began investigating and monitoring water-quality conditions and suspended-sediment transport in the Wilson and Trask Rivers, northwestern Oregon. Water temperature, specific conductance, turbidity, and dissolved oxygen were measured every 15–30 minutes in both streams using real-time instream water-quality monitors. In conjunction with the monitoring effort, suspended-sediment samples were collected and analyzed to model the amount of suspended sediment being transported by each river. Over the course of the 3-year study, which ended in September 2014, nearly 600,000 tons (t) of suspended-sediment material entered Tillamook Bay from these two tributaries. Each year of the study, the Wilson River transported between 80,300 and 240,000 t of suspended sediment, while the Trask River contributed between 28,200 and 69,900 t. The suspended-sediment loads observed during the study were relatively small because streamflow conditions were routinely lower than normal between October 2011 and September 2014. Only one storm had a recurrence interval between a 2- and 5-year event. Every other storm produced streamflows equivalent to what would be classified as a 1- or 2-year event. Because most sediment moves during high flows, the lack of heavy rainfall and elevated streamflows muted any high sediment loads. Along with assessing suspended-sediment transport, the U.S. Geological Survey also monitored instream water quality. This monitoring was used to track instream conditions and relate them to water temperature, dissolved oxygen, and sedimentation issues for the Wilson and Trask Rivers. Stream temperatures in the Wilson and Trask Rivers exceeded the temperature standard for cold-water habitat. Water temperatures at both streams exceeded the standard for more than 30 percent of the year, as stream temperatures increased above the seasonal 13 degrees Celsius (°C) (seasonal core cold-water habitat) and 16 °C (salmon and steelhead [ Oncorhynchus mykiss ] spawning) thresholds. Conversely, dissolved oxygen concentrations rarely decreased to less than the absolute water-quality criterion of 8 milligrams per liter for cold-water streams. Results from this study will provide resource managers insight into the seasonality of water-quality conditions and the extent of suspended-sediment transport in the Wilson and Trask Rivers. The data are useful for establishing a baseline and for maintaining best-use land management practices and possibly for aiding in prioritization of restoration actions for both rivers and their respective watersheds.

Oregon↗
USGS1979

Investigations by the U.S. Geological Survey of soil and moisture conservation on public domain lands, 1941-1964

The passage of the Taylor Grazing Act in 1934 marked the end of an era in the land policies in the United States in that disposal of the public lands by homesteading was terminated except under rigidly prescribed procedures, and the remaining public lands covering about 175 million acres in the western conterminous states were brought under regulatory authority for grazing use. In 1934 the lands were mostly in a severe state of deterioration as a result of overgrazing and drought. In addition to reducing numbers of livestock using the lands, successive programs of conservation practices were established of which the Soil and Moisture Conservation Program of the Department of the Interior is of particular interest here. The services of the Geological Survey, in an investigational and advisory capacity were enlisted in this program. The work of the Geological Survey has consisted of the collection of hydrologic data, investigations of range-water supplies to facilitate management and provide information for design of structures and land-treatment measures. Appraisal of the effects of treatment practices has also been an important activity. Conservation on the public domain involves mainly growing vegetation for forage and reducing erosion. The two elements are intimately related--accomplishment in one is usually reflected by an improvement in the other. Erosion is a serious problem on most of the public domain, but particularly in the Colorado River and Rio Grande basins where, despite low annual water yields, the public domain and similar lands on the Indian reservations contribute the major part of the sediment measured at the downstream gaging stations. In parts of the Missouri River basin also, erosion is obviously very active but the sediment yield contributed by the public domain cannot be as readily isolated. The reasons for the erosion are generally evident--the erodibility of the rock and soils and the sparsity of vegetation as a result of low precipitation, unfavorable soils, or past land use. How much is due to the land use is still controversial, resulting in many questions relative to planning corrective measures. The problem facing the early administrators of the Taylor Grazing Act to bring about proper use and conservation of the public domain was a difficult one because of the lack of records on actual grazing use in animal-unit months of the qualified allottees and the lack of data on treatment practices in an arid area. Reduction of grazing was imperative in some localities, but generally, it could not be brought about as rapidly as it should have been. Numbers of animal units in the grazing districts were reduced from about 3.6 million in 1941 to about 3.2 million in 1964, whereas the areas included in districts was increased about 3 percent. Reductions are still being made in certain areas where deterioration is evident. One of the earliest activities connected with management of the range was the development of water supplies to facilitate the distribution of grazing. The investigations needed for such development formed a large part of the early work in the Soil and Moisture program of the Geological Survey and has continued to be a major activity to the present time. Most of the work has involved investigations of sites for wells but has included also the investigation of proposed spring developments and collection of hydrologic data for use in reservoir design. Well-site investigations have been of two general types: (1) the investigation of a site selected by the land administration agency, and (2) an areal investigation covering entire grazing districts or units thereof. In each type of investigation, a study is made of the geology and the recharge conditions. Reports are prepared giving estimates of the depth of drilling required, the depth to water, the yield, and the quality of the water, together with other information on drilling conditions and developing. Springs are a significant so

Open-File Report↗
USGS2014

The use of resistivity‐methods in the location of salt‐water bodies in the El Paso, Texas, Area

During 1935 and 1936 the Ground‐Water Division of the United States Geological Survey made an investigation of the ground‐water resources of the El Paso, Texas, Area. Geological and hydrological studies comprised the principal part of the investigation, and these studies were supplemented by measurements of earth‐resistivity made largely by the Geophysical Section of the Geological Survey along traverses aggregating 51 miles. The extent to which resistivity‐methods may be useful in ground‐water work has been the subject of much discussion. A full evaluation of the method can not be made at this time. However, the work in the El Paso Area indicates that the presence of faults and of underground bodies of salt water may be definitely determined by resistivity‐measurements.

Texas↗
USGS2004

Estimation of a water budget for 1972-2000 for the Grasslands Area, central part of the Western San Joaquin Valley, California

Equitable implementation of regulations restricting discharges from agricultural drains into the San Joaquin River requires a greater understanding of the influence of extreme precipitation events on the ground-water flow system. As part of a larger investigation, this study estimated ground-water recharge and ground-water pumpage, two important components of the water budget in the Grasslands drainage area in the central part of the western San Joaquin Valley, California, for the water years 1972 through 2000. These estimates will be used as inputs to a numerical simulation model of the regional ground-water flow system in the continuing investigation. Crop-acreage and surface-water delivery data were compiled for 14 water districts and 6 other areas comprising approximately 97 percent of the 600-square-mile study area. Little ground-water pumpage data exists for the study area. A climate-based approach was employed to estimate annual water-table recharge flux and ground-water pumpage for 11 water-budget areas. Ground-water pumpage was estimated from the residual irrigation demand after crop consumption of surface water. Estimated recharge flux to the water table for the entire study area averaged 0.8 ft/yr, and estimated ground-water pumpage per unit area for the entire study area averaged 0.5 ft/yr. Increased discharges from agricultural drains in the late 1990s may have been due partly to 4 years of high recharge from precipitation over the 6-year period from 1993 to 1998. Knowledge of the ratio of annual crop water demand to annual potential evapotranspiration, expressed as an aggregate crop coefficient, Kd, will facilitate estimation of annual water-budget components in future studies. Annual aggregate crop coefficients, calculated each year for the entire study area, were nearly constant at 0.59 from 1983 to 2000, and reasonably constant at 0.53 prior to 1983. The overall trend suggests continuous reductions in recharge from irrigation over time. This reduction is most likely due to gradual improvements in irrigation management. The recharge and pumpage estimates are both sensitive to the consumption-distribution ratio, and the pumpage estimate is sensitive to the cropped acreage.

Scientific Investigations Report↗
USGS1979

Ground-water conditions and potential for artificial recharge in Lucerne Valley, San Bernardino County, California

The water level in two areas of Lucerne Valley has declined more than 100 feet since 1917, including 60 feet from 1954 to 1976. These declines are the result of pumping for the irrigation of alfalfa. The lowering of water levels has caused many shallow domestic wells to go dry. Well yields in the valley generally are between 10 and 1,000 gallons per minute. About 240,000 acre-feet of ground water was extracted between 1950 and 1976. About 1,750,000 acre-feet remains in storage. Water of poor quality underlies the valley around Lucerne Lake. There was no definable movement of this water from 1954 to 1976, but the possibility exists for future movement toward centers of pumping. Lucerne Valley may be hydrologically suitable for artificial-recharge operations. Preliminary data suggest an area in T. 4 N., R. 1 E. as suitable for artificial recharge that would benefit most of the areas affected by the water-level declines. Detailed investigation is needed before recharge operations are begun.

California↗
USGS2007

Recharge area, base-flow and quick-flow discharge rates and ages, and general water quality of Big Spring in Carter County, Missouri, 2000-04

Exploration for lead deposits has occurred in a mature karst area of southeast Missouri that is highly valued for its scenic beauty and recreational opportunities. The area contains the two largest springs in Missouri (Big Spring and Greer Spring), both of which flow into federally designated scenic rivers. Concerns about potential mining effects on the area ground water and aquatic biota prompted an investigation of Big Spring. Water-level measurements made during 2000 helped define the recharge area of Big Spring, Greer Spring, Mammoth Spring, and Boze Mill Spring. The data infer two distinct potentiometric surfaces. The shallow potentiometric surface, where the depth-to-water is less than about 250 feet, tends to mimic topographic features and is strongly controlled by streams. The deep potentiometric surface, where the depth-to-water is greater than about 250 feet represents ground-water hydraulic heads within the more mature karst areas. A highly permeable zone extends about 20 mile west of Big Spring toward the upper Hurricane Creek Basin. Deeper flowing water in the Big Spring recharge area is directed toward this permeable zone. The estimated sizes of the spring recharge areas are 426 square miles for Big Spring, 352 square miles for Greer Spring, 290 square miles for Mammoth Spring, and 54 square miles for Boze Mill Spring. A discharge accumulation curve using Big Spring daily mean discharge data shows no substantial change in the discharge pattern of Big Spring during the period of record (water years 1922 through 2004). The extended periods when the spring flow deviated from the trend line can be attributed to prolonged departures from normal precipitation. The maximum possible instantaneous flow from Big Spring has not been adequately defined because of backwater effects from the Current River during high-flow conditions. Physical constraints within the spring conduit system may restrict its maximum flow. The largest discharge measured at Big Spring during the period of record (water years 1922 through 2004) was 1,170 cubic feet per second on December 7, 1982. The daily mean water temperature of Big Spring was monitored during water years 2001 through 2004 and showed little variability, ranging from 13 to 15° C (degree Celsius). Water temperatures generally vary less than 1° C throughout the year. The warmest temperatures occur during October and November and decrease until April, indicating Big Spring water temperature does show a slight seasonal variation. The use of the traditional hydrograph separation program HYSEP to determine the base flow and quick flow or runoff components at Big Spring failed to yield base-flow and quick-flow discharge curves that matched observations of spring characteristics. Big Spring discharge data were used in combination with specific conductance data to develop an improved hydrograph separation method for the spring. The estimated annual mean quick flow ranged from 15 to 48 cubic feet per second for the HYSEP analysis and ranged from 26 to 154 cubic feet per second for the discharge and specific conductance method for water years 2001 to 2004. Using the discharge and specific conductance method, the estimated base-flow component rises abruptly as the spring hydrograph rises, attains a peak value on the same day as the discharge peak, and then declines abruptly from its peak value. Several days later, base flow begins to increase again at an approximately linear trend, coinciding with the time at which the percentage of quick flow has reached a maximum after each recharge-induced discharge peak. The interval between the discharge peak and the peak in percentage quick flow ranges from 8 to 11 days for seven hydrograph peaks, consistent with quick-flow traveltime estimates by dye-trace tests from the mature karst Hurricane Creek Basin in the central part of the recharge area. Concentrations of environmental tracers chlorofluorocarbons (CFCs: CFC-11, CFC-12, CFC-113), and sulfur hexafluoride in discharge from Big Spring vary approximately linearly with percent quick flow from about 5 to 45 percent of discharge. Linear extrapolation to 100 percent quick flow implies CFC and SF 6 concentrations nearly identical to those in the 2002 atmosphere and indicates a modern age for the quick-flow component. Tracer concentrations for less than about 5 percent quick flow are increasingly lower than those expected from linear extrapolation to zero percent quick flow, indicating that the reservoir of older water in the Big Spring watershed may be a series of water mixtures with piston-flow ages greater than those obtained by extrapolation to zero percent quick flow. Each sample point with a low percentage of quick flow (less than 5 percent) may be a unique mixture. Environmental tracer data from Big Spring plot intermediate to the simple binary mixing of modern and old, pre-tracer water and results from the exponential mixture model. The mean ages of waters in the base-flow component approximately range from 30 to 200 years. The mean age of the base-flow component is youngest (30 to 40 years) in samples containing the highest quick-flow component (45 percent quick flow) and increases to 200 years or more as the fraction of quick flow decreases to less than 5 percent. Tritium data are consistent with a model of dilution of a modern component with an old, pre-tracer component and indicates that the old fraction is mostly pre-1960s in age with mean residence time of more than several hundred years. All of the samples from Big Spring and Greer Spring have water temperatures warmer than their nitrogen-argon recharge temperature, which range from approximately 10.5 to 14° C, suggesting recharge to the Big Spring watershed occurs primarily in late winter to early spring. The water temperatures at Big Spring are consistent with relatively shallow circulation (less than about 600 feet), and the water does not appear to be warmed by deep circulation along a geothermal gradient. Specific conductance values and concentrations of most inorganic constituents in water samples from Big Spring generally decrease with increasing discharge because of dilution with quick-flow water of lower ionic strength. Concentrations of some constituents such as chloride and nitrite plus nitrate, and fecal coliform densities, however, did not decrease with increasing discharge, indicating that quick flow probably is a more important source of these constituents compared to base flow. Water samples from Big Spring plot along the line of dolomite dissolution by carbonic acid, are at equilibrium with dolomite and calcite, and have a molar ratio of Ca:Mg of near 1, indicating dissolution of the mineral dolomite as the primary control on concentrations of calcium, magnesium, and bicarbonate. The flux of calcium and magnesium from Big Spring represents the dissolution of about 1,950 cubic feet of dolomite per day. The suspended sediment load of Big Spring was estimated to range from about 1 to about 70 tons per day, and the sediment load during base-flow periods ranged from about 1 to about 7 tons per day.

Missouri↗
USGS2005

Arsenic in ground water of the United States: occurrence and geochemistry

Concentrations of naturally occurring arsenic in ground water vary regionally due to a combination of climate and geology. Although slightly less than half of 30,000 arsenic analyses of ground water in the United States were 1 μg/L, about 10% exceeded 10 μg/L. At a broad regional scale, arsenic concentrations exceeding 10 μg/L appear to be more frequently observed in the western United States than in the eastern half. Arsenic concentrations in ground water of the Appalachian Highlands and the Atlantic Plain generally are very low ( 1 μg/L). Concentrations are somewhat greater in the Interior Plains and the Rocky Mountain System. Investigations of ground water in New England, Michigan, Minnesota, South Dakota, Oklahoma, and Wisconsin within the last decade suggest that arsenic concentrations exceeding 10 μg/L are more widespread and common than previously recognized. Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 μg/L in ground water. This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (i.e., petroleum products) organic carbon. Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the western United States. Sulfide minerals are both a source and sink for arsenic. Geothermal water and high evaporation rates also are associated with arsenic concentrations 10g/L in ground and surface water, particularly in the west. Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 µg/L a ground water. This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (i.e., petroleum products) organic carbon. Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the Western United States. Sulfide minerals are both a source and sink for arsenic. Geothermal water and high evaporation rates also are associated with arsenic concentrations ≥ 10g/L in ground and surface water, particularly in the west.

Ground Water↗
USGS1997

Ground-water flow in the Saginaw aquifer in the vicinity of the north Lansing well field, Lansing Michigan — Part 2, simulations with a regional model using a reduced cell size

Vinyl chloride has been detected in water from the Saginaw aquifer near Lansing Board of Water and Light wells in the north Lansing well field. These public-supply wells have the potential to withdraw contaminated ground water. The effects of reduced grid spacing for the existing TriCounty regional ground-water-flow model on local ground-water movement were investigated. This refinement of the grid eliminated multiple wells in a cell and reduced the number of wells represented as weak sinks. Two pumping scenarios were developed to investigate the effects of pumping conditions, plume size, and hypothetical purge well locations on the movement of the vinyl chloride plume in the Saginaw aquifer. Under 1995 pumping conditions, water that originates in the central portion of the Saginaw aquifer known to be contaminated with vinyl chloride is prevented from reaching Lansing Board of Water and Light supply wells when hypothetical purge wells located west of the plume are simulated as pumping either 100 gallons per minute or 200 gallons per minute. Purge wells located north of the plume are effective at preventing contamination from reaching Lansing Board of Water and Light supply wells when simulated as pumping 200 gallons per minute. Water that originates within and surrounding the area known to be contaminated with vinyl chloride is not prevented from reaching Lansing Board of Water and Light supply wells under 1995 conditions using either purge well location or pumping rate. Under 1997 pumping conditions, water that originates in the central portion of the Saginaw aquifer known to be contaminated with vinyl chloride is prevented from reaching Lansing Board of Water and Light supply wells when hypothetical purge wells located either west or north of the plume are simulated as pumping 200 gallons per minute. Water that originates within and surrounding the area known to be contaminated with vinyl chloride is not prevented from reaching Lansing Board of Water and Light supply wells under 1997 conditions using either purge well location or pumping rate.

Michigan↗
USGS1993

Water quality of Corydon Reservoir before implementation of agricultural best-management practices in the basin, Wayne County, Iowa, September 1990 to September 1991

A hydrologic investigation to define the water quality of Corydon Reservoir before implementation of agricultural best-management practices in the basin was conducted from September 1990 to September 1991. Runoff from the 1,680-acre basin is the primary source of water to the 58-acre reservoir. Current water quality of the reservoir is affected substantially by runoff from the agricultural basin. Total-solids, total-nitrogen, and total-phosphorus concentrations were largest during April through July 1991, the months of greatest rainfall. Herbicide concentrations increased substantially in June after application. The concentration of the sum of all triazines was greater than 50 micrograms per liter in one sample, with the predominant herbicides being atrazine and cyanazine. Atrazine concentrations, estimated from immunoassay, were greater than 8.0 micrograms per liter from June through September 1991 as a result of reservoir storage. Atrazine concentrations commonly were less at the surface than at depth. Algal populations remained constant even though nutrient concen- trations increased during the summer months. This may be due to the presence of suspended sediment that reduces light penetration and herbicides that inhibit photosynthesis.

Iowa↗
USGS1971

Resistivity sections, upper Arkansas River basin, Colorado

A reconnaissance investigation of ground-water resources in the upper Arkansas River basin from Pueblo to Leadville is being made by the U.S. Geological Survey in cooperation with the Southeastern Colorado Water Conservancy District, and the Colorado Division of Water Resources, Colorado State Engineer. As part of the investigation, surface geophysical electrical resistivity surveys were made during the summer and fall of 1970 near Buena Vista and Westcliffe, Colo. (p1.1). The resistivity surveys were made to verify a previous gravity survey and to help locate areas where ground-water supplies might be developed. This report presents the results of the surveys in the form of two resistivity sections.

Colorado↗
USGS2017

Synoptic sampling and principal components analysis to identify sources of water and metals to an acid mine drainage stream

Combining the synoptic mass balance approach with principal components analysis (PCA) can be an effective method for discretising the chemistry of inflows and source areas in watersheds where contamination is diffuse in nature and/or complicated by groundwater interactions. This paper presents a field-scale study in which synoptic sampling and PCA are employed in a mineralized watershed (Lion Creek, Colorado, USA) under low flow conditions to (i) quantify the impacts of mining activity on stream water quality; (ii) quantify the spatial pattern of constituent loading; and (iii) identify inflow sources most responsible for observed changes in stream chemistry and constituent loading. Several of the constituents investigated (Al, Cd, Cu, Fe, Mn, Zn) fail to meet chronic aquatic life standards along most of the study reach. The spatial pattern of constituent loading suggests four primary sources of contamination under low flow conditions. Three of these sources are associated with acidic (pH <3.1) seeps that enter along the left bank of Lion Creek. Investigation of inflow water (trace metal and major ion) chemistry using PCA suggests a hydraulic connection between many of the left bank inflows and mine water in the Minnesota Mine shaft located to the north-east of the river channel. In addition, water chemistry data during a rainfall-runoff event suggests the spatial pattern of constituent loading may be modified during rainfall due to dissolution of efflorescent salts or erosion of streamside tailings. These data point to the complexity of contaminant mobilisation processes and constituent loading in mining-affected watersheds but the combined synoptic sampling and PCA approach enables a conceptual model of contaminant dynamics to be developed to inform remediation.

Environmental Science and Pollution Research↗
USGS2007

Evapotranspiration from a bulrush-dominated wetland in the Klamath Basin, Oregon

Growing-season evapotranspiration and surface energy and water balances were investigated for an extensive, bulrush-dominated wetland in the Upper Klamath National Wildlife Refuge of south-central Oregon, a semi-arid region with competing demands for scarce water resources. Turbulent fluxes of sensible and latent heat were measured by eddy covariance for 1.2 to 1.9 days during each of four site visits during late-May to mid-October 1997. Mean daytime latent heat flux and the Bowen ratio ranged from 148 to 178 W m −2 and from 0.38 to 0.51, respectively, during late May, mid-July, and late August site visits. By mid-October, when the plant canopy had senesced, daytime latent heat flux and the Bowen ratio averaged 46 W m −2 and 2.8, respectively. An hourly Penman-Monteith (PM) model that was fitted to the surface-flux data provided values for the surface resistance to water-vapor diffusion that ranged from 78 s m −1 during late August to 206 s m −1 during mid-October. Similarly, a Priestley-Taylor (PT) model provided values for the PT multiplier (a) that ranged from 0.96 during late August to 0.37 during mid-October. The PM and PT models predicted evapotranspiration totals of 560 and 480 mm, respectively, for May 28 to October 12, 1997.

Oregon↗
USGS1993

Streamflow and water-quality data for Lake Purdy and its tributaries, Jefferson and Shelby Counties, Alabama, water years 1987-91

An investigation was begun in North Carolina in 1988 to: (1) quantify nutrient, sediment, and freshwater loadings in canals that collect drainage from cropland field ditches; (2) determine the effects of tide gates and flashboard risers on these loadings and on receiving-water quality; and (3) characterize the effects of drainage on the salinity regime of a tidal creek. Data were collected in three canals in Hyde County, three canals in Beaufort County, and in Campbell Creek, which receives drainage directly from two of the Beaufort County canals. Water-control structures were placed on two of the six canals near the beginning of the investigation. Following about 2 years of data collection, control structures were placed on the remaining four canals. Hydrologic and water-quality data are presented for each of the study sites for the period of October 1990 through May 1992. Data presented in this report cover the second phase of the investigation after the installation of water-control structures in the six drainage canals. Following a description of the study sites and data-collection methods, data are presented for five of the drainage canals and Campbell Creek. Data collection was discontinued at one of the Beaufort County sites after the first phase of the investigation. The data collected include: (1) daily values of accumulated precipitation; (2) water-level statistics; (3) daily mean values of discharge in the canals; (4) biweekly water-quality measurements and sample analyses; (5) storm-event water-quality measurements and sample analyses; (6) continuous records of specific conductance in the canals; (7) vertical profiles of salinity in Campbell Creek; and (8) daily mean values of salinity at five sites in Campbell Creek.

Open-File Report↗
USGS1965

Reevaluation of the ground-water resources of Tooele Valley, Utah

This study of the geohydrology of Tooele Valley, Utah, was made by the U.S. Geological Survey in cooperation with the Utah State Engineer during the period 1958-63. The purpose of the study was to update an earlier investigation of ground water in Tooele Valley made by the Geological Survey during 1940-42 (Thomas, 1946). The construction of approximately 256 wells in the valley since 1940, many of which are large-diameter pumped wells drilled since 1950, made available new data on water levels, well discharge, and chemical quality for interpretation of ground-water conditions. New data also were available on spring discharge, streamflow, aquifer characteristics, and geologic, geophysical, and climatic conditions. The earlier report by Thomas (1946) was freely used during the preparation of this report.

Utah↗
USGS2004

Preliminary investigation of structural controls of ground-water movement in Pipe Spring National Monument, Arizona

Pipe Spring National Monument, near the border of Arizona and Utah, includes several low-discharge springs that are the primary natural features of the monument. The National Park Service is concerned about the declines in spring discharge. Seismic-refraction and frequency-domain electromagnetic-induction methods were employed in an attempt to better understand the relation between spring discharge and geologic structure. The particular method used for the seismic-refraction surveys was unable to resolve structural features in the monument. Electromagnetic surveys delineated differences in apparent conductivity of the shallow subsurface deposits. The differences are attributable to differences in saturation, lithology, and structure of these deposits.

Scientific Investigations Report↗