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At least 1,531 records · Page 85Linked to original sources

Specific conductance in the Colorado River between Glen Canyon Dam and Diamond Creek, Northern Arizona, 1988-2007

The construction of Glen Canyon Dam, completed in 1963, resulted in substantial physical and biological changes to downstream Colorado River environments between Lake Powell and Lake Mead - an area almost entirely within Grand Canyon National Park, Ariz. In an effort to understand these changes, data have been collected to assess the condition of a number of downstream resources. In terms of measuring water quality, the collection of specific-conductance data is a cost-effective method for estimating salinity. Data-collection activities were initially undertaken by the Bureau of Reclamation's Glen Canyon Environmental Studies (1982-96); these efforts were subsequently transferred to the U.S. Geological Survey's Grand Canyon Monitoring and Research Center (1996 to the present). This report describes the specific-conductance dataset collected for the Colorado River between Glen Canyon Dam and Diamond Creek from 1988 to 2007. Data-collection and processing methods used during the study period are described, and time-series plots of the data are presented. The report also includes plots showing the relation between specific conductance and total dissolved solids. Examples of the use of specific conductance as a natural tracer of parcels of water are presented. Analysis of the data indicates that short-duration spikes and troughs in specific-conductance values lasting from hours to days are primarily the result of flooding in the Paria and Little Colorado Rivers, Colorado River tributaries below Glen Canyon Dam. Specific conductance also exhibits seasonal variations owing to changes in the position of density layers within the reservoir; these changes are driven by inflow hydrology, meteorological conditions, and background stratification. Longer term trends in Colorado River specific conductance are reflective of climatological conditions in the upper Colorado River Basin. For example, drought conditions generally result in an increase in specific conductance in Lake Powell. Therefore, the average annual specific conductance below Glen Canyon Dam is inversely related to the volume of water in Lake Powell.

Arizona↗

Depth-dependent sampling to identify short-circuit pathways to public-supply wells in multiple aquifer settings in the United States

Depth-dependent water-quality and borehole flow data were used to determine where and how contamination enters public-supply wells (PSWs) at study sites in different principal aquifers of the United States. At each of three study sites, depth-dependent samples and wellbore flow data were collected from multiple depths in selected PSWs under pumping conditions. The chemistry of these depth-dependent samples, along with samples of the surface discharge from the PSWs, was compared to that of adjacent nested monitoring wells. The results of depth-dependent analyses from sites in Modesto (California), York (Nebraska), and Tampa (Florida) are summarized and compared. Although the exact mechanisms for transport of contaminants to the PSWs varied among these hydrogeologic settings, in all three settings the presence of wells or boreholes or natural preferential flow paths allowed water and contaminants to bypass substantial portions of the aquifer and to reach PSWs or depths in the aquifer more quickly than would have occurred in the absence of these short-circuiting flow paths. The chemistry and flow data from multiple depths was essential to developing an understanding of the dominant flow paths of contaminants to PSW in all three settings. This knowledge contributes to developing effective strategies for monitoring and protection.

Hydrogeology Journal↗

Habitat use of juvenile pallid sturgeon and shovelnose sturgeon with implications for water-level management in a downstream reservoir

Natural recruitment of pallid sturgeon Scaphirhynchus albus has not been observed in the Missouri River above Fort Peck Reservoir, Montana, for at least 20 years. To augment the population, age-1 hatchery-reared juvenile pallid sturgeon were released in 1998. The objective of this study was to evaluate the habitat use of these fish and compare it with that of indigenous shovelnose sturgeon S. platorynchus. Twenty-nine juvenile pallid sturgeon and 21 indigenous shovelnose sturgeon were implanted with radio transmitters in 2003 and 2004. The two species showed no differences in habitat use in terms of mean depth, cross-sectional relative depth, longitudinal relative depth, column velocity, bottom velocity, and channel width. However, there were seasonal differences within both species for cross-sectional relative depth, column velocity, and channel width. Both shovelnose sturgeon and juvenile pallid sturgeon were primarily associated with silt and sand substrate. However, shovelnose sturgeon were associated with gravel and cobble substrate more than juvenile pallid sturgeon. Shovelnose sturgeon and juvenile pallid sturgeon both selected reaches without islands and avoided reaches with islands; the two species also selected main-channel habitat and avoided secondary channels. Mean home range was similar between juvenile pallid sturgeon (15 km; 90% confidence interval, ??5.0 km) and shovelnose sturgeon (16.5 km; ??4.7 km). Spatial distribution differed between the two species, with shovelnose sturgeon using upstream areas more often than juvenile pallid sturgeon. Twenty-eight percent of juvenile pallid sturgeon frequented 60 km of lotie habitat that would be inundated by Fort Peck Reservoir at maximum pool. Stocking juvenile pallid sturgeon can successfully augment the wild pallid sturgeon population in the Missouri River above Fort Peck Reservoir, which is crucial to the long-term recovery of the species. However, water-level management in downstream reservoirs such as Fort Peck can influence the amount of habitat available for pallid sturgeon. ?? Copyright by the American Fisheries Society 2008.

North American Journal of Fisheries Management↗

De facto water reuse: Bioassay suite approach delivers depth and breadth in endocrine active compound detection

Although endocrine disrupting compounds (EDCs) have been detected in wastewater and surface waters worldwide using a variety of in vitro effects-based screening tools, e.g. bioassays, few have examined potential attenuation of environmental contaminants by both natural (sorption, degradation, etc) and anthropogenic (water treatment practices) processes. This study used several bioassays and quantitative chemical analyses to assess residence-time weighted samples at six sites along a river in the northeastern United States beginning upstream of a waste water treatment plant (WWTP) outfall and proceeding downstream along the stream reach to a drinking water treatment plant (DWTP). Known steroidal estrogens were quantified and changes in signaling pathway molecular initiating events (activation of estrogen, androgen, glucocorticoid, peroxisome proliferator-activated, pregnane X receptor, and aryl hydrocarbon receptor signaling networks) were identified in water extracts. In initial multi-endpoint assays geographic and receptor-specific endocrine activity patterns in transcription factor signatures and nuclear receptor activation were discovered. In subsequent single endpoint receptor-specific bioassays, estrogen (16 of 18 samples; 0.01 to 28 ng estradiol equivalents [E2Eqs]/L) glucocorticoid (3 of 18 samples; 1.8 to 21 ng dexamethasone equivalents [DexEqs]/L), and androgen (2 of 18 samples; 0.95 to 2.1 ng dihydrotestosterone equivalents [DHTEqs]/L) receptor transcriptional activation occurred above respective assay method detection limits (0.04 ng E2Eqs/L, 1.2 ng DexEqs/L, and 0.77 ng DHTEqs/L) in multiple sampling events. Estrogen activity, the most often detected, correlated well with measured concentrations of known steroidal estrogens (R2 = 0.890). Overall, activity indicative of multiple types of endocrine active compounds was highest in wastewater effluent samples, while activity downstream was progressively lower, and negligible in (unfinished) treated water. This multiple bioassay approach, in conjunction with targeted analytical chemistry methods, has gained acceptance among water quality screening programs. Not only was estrogenic and glucocorticoid activity confirmed in the effluent by utilizing multiple methods concurrently, but other activated signaling networks that historically received less attention (i.e. peroxisome proliferator-activated receptor) were also detected.

Science of the Total Environment↗

Laboratory simulated transport of microcystin-LR and cylindrospermopsin in groundwater under the influence of stormwater ponds: implications for harvesting of infiltrated stormwater

Water shortages in the southeastern United States have led to a need for more intensive management and usage of stormwater for beneficial uses such as irrigation. Harvesting of infiltrated stormwater from horizontal wells in sandy aquifer sediments beneath stormwater ponds has emerged as an alternative in need of evaluation. Cyanobacteria may proliferate in stormwater ponds; cyanotoxins produced by these organisms represent potential public health concerns. Results of two, saturated flow, sand column experiments indicate breakthrough of microcystin-LR (MCLR) and cylindrospermopsin (CYL) within 1―2 pore volumes indicating little removal attributable to sorption. Concentration-based MCLR removal efficiencies up to 90% were achieved, which we hypothesize were predominantly due to biodegradation. In contrast, CYL removal efficiencies were generally less than 15%. On the basis of these results, removal of sandy soil in the stormwater pond bottom and addition of sorption media with greater binding affinities to cyanotoxins may enhance natural attenuation processes prior to water withdrawal.

Conference Paper↗

Surface-Water Quality Conditions and Long-Term Trends at Selected Sites within the Ambient Water-Quality Monitoring Network in Missouri, Water Years 1993-2008

The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, collects data pertaining to the surface-water resources of Missouri. These data are collected as part of the Missouri Ambient Water-Quality Monitoring Network and constitute a valuable source of reliable, impartial, and timely information for developing an improved understanding of water resources in the State. Six sites from the Ambient Water-Quality Monitoring Network, with data available from the 1993 through 2008 water years, were chosen to compare water-quality conditions and long-term trends of dissolved oxygen, selected physical properties, total suspended solids, dissolved nitrate plus nitrite as nitrogen, total phosphorous, fecal indicator bacteria, and selected trace elements. The six sites used in the study were classified in groups corresponding to the physiography, main land use, and drainage basin size, and represent most stream types in Missouri. Long-term trends in this study were analyzed using flow-adjusted and non-flow adjusted models. Highly censored datasets (greater than 5 percent but less than 50 percent censored values) were not flow-adjusted. Trends that were detected can possibly be related to changes in agriculture or urban development within the drainage basins. Trends in nutrients were the most prevalent. Upward flow-adjusted trends in dissolved nitrate plus nitrite (as nitrogen) concentrations were identified at the Elk River site, and in total phosphorus concentrations at the South Fabius and Grand River sites. A downward flow-adjusted trend was identified in total phosphorus concentrations from Wilson Creek, the only urban site in the study. The downward trend in phosphorus possibly was related to a phosphorus reduction system that began operation in 2001 at a wastewater treatment plant upstream from the sampling site. Total suspended solids concentrations indicated an upward non-flow adjusted trend at the two northern sites (South Fabius and Grand Rivers). The increase in total suspended solids concentrations could be because of soil erosion from land cultivated for row crops. Most trace element data examined in the study were highly censored and could not be used for flow-adjusted trend analyses. Water-quality conditions were assessed to explore relations between data from sites and to the State water-quality standards where applicable for selected constituents. Streamflow varied at each site because of drainage area, land use, and groundwater inputs. Dissolved oxygen and water temperature were similar at all sites except the urban site located on Wilson Creek. Specific conductance was similar between the most northern (South Fabius and Grand River sites) and the most southern sites (Current and Elk River sites). Total suspended solids concentrations were near the method reporting level at all sites, except the northern sites. Streams in northern Missouri are more turbid than streams in southern Missouri and are affected by large volumes of sediment deposition because of soil erosion from land cultivated for row crops. Geometric means of Escherichia coli were calculated from the recreational seasons within the study period. Only the Grand River site exceeded the whole-body-contact standard for frequently used waters. The South Fabius and Grand River sites and the Wilson Creek site had statistically larger densities of both fecal indicator bacteria types than the remaining sites.

Scientific Investigations Report↗

General water-quality conditions, long-term trends, and network analysis at selected sites within the Ambient Water-Quality Monitoring Network in Missouri, water years 1993–2017

The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, collects data pertaining to the surface-water resources of Missouri. Established in 1964, the Ambient Water-Quality Monitoring Network (AWQMN) consisted of 69 sites in 2017. Two additional sites from the National Water-Quality Program are included with the AWQMN sites for the analyses in this report. The sites are sampled typically from 2 to 12 times per year for physical properties, total suspended solids, nutrients, fecal indicator bacteria, and trace elements. The period of analysis for this study was from 1993 through 2017 and data analysis included 71 sites and 15 water-quality constituents plus discharge. Data analysis involved retrieving the data, conditioning the data for analysis, analyzing the data for trends, and analyzing the monitoring network to determine if potential data gaps or data redundancies exist in the network. Results from these analyses can be used to help manage the monitoring network into the future. Water-quality data were analyzed using several software packages to provide graphical and statistical information for interpretation of trends in the data at selected sites. Discharge data at selected sites were analyzed to determine the general trends during the analysis period and how the water-quality samples represented the range of daily mean discharges at each site. Water-quality data also were analyzed at selected sites to determine the relative sensitivity of selected sites and constituents to changes in data collection frequency. Trend analysis at selected sites using a simulated reduction in sampling frequency was completed to compare to trends obtained using monthly data to determine the potential degradation in the ability of determining trends from a reduced sampling frequency. The viability of using estimated discharge to evaluate long-term trends for sites with no continuous discharge was investigated. Data from sites were statistically compared in groups to determine the relative similarity (or difference) between sites for each water-quality constituent to identify potentially redundant sites in the monitoring network. Discharge-weighted long-term trends during 1993 through 2017 were analyzed for 15 water-quality constituents at 58 sites and results indicated there were significant single- or two-period trends in about 17 percent of the analyses. Some trends indicated improvement and some trends indicated deterioration of the general water quality at some sites in the AWQMN. No trend was indicated in about 31 percent of the analyses. The constituents pH, specific conductance, and total phosphorus showed the most frequent significant trends, and each of the 15 constituents examined had a significant trend at one or more sites. A total of 42 sites indicated at least 1 constituent with a significant single- or two-period trend, and 10 sites indicated 6 or more significant trends. Potential data gaps identified for computing discharge-weighted long-term trends in the monitoring network included the lack of collection of continuous discharge at 23 sites, insufficient sampling frequency for some constituents (dissolved chloride and total and dissolved lead and zinc) at some sites, insufficient temporal sample distribution (lack of at least one sample in each season per year) at some sites, and insufficient sampling frequency for some highly censored constituents (nutrients and total and dissolved lead and zinc) at some sites. Potential data gaps based on site spatial distribution were identified in 7 basins greater than 800 square miles. Potential site redundancies were identified in 4 basins that had an area greater than 500 square miles with a site density greater than 2 sites per 1,000 square miles. Potential site redundancies also were identified for nine site pairs by observing statistical similarities in the constituent data distributions. Sampling frequency was investigated to determine if reducing the sampling frequency of select constituents could provide a statistically similar data distribution. At 28 of 71 sites, 11 constituents had sufficient data collection frequency (approximately monthly) to allow for the creation of simulated datasets of various reduced data collection frequency. For the selected monitoring network sites analyzed, the data distribution of a simulated sampling frequency of four times per year or greater, roughly evenly distributed over the year, was not significantly different than the data distribution of the original monthly sampling frequency. Sites analyzed using varying simulated sampling frequencies tended to be more sensitive to sampling frequency changes if they were in basins classified as large or very large size and tended to be least sensitive in basins classified as small and medium size in the Ozark Plateaus Province. Simulated reduced frequency sampling analysis indicated that the constituents and measurements most sensitive to changes in sampling frequencies were water temperature, dissolved oxygen, discharge, and dissolved nitrate, and least sensitive were pH, total suspended solids, dissolved phosphorus, and total phosphorus. Discharge-weighted long-term trend analysis was repeated at 22 sites for 11 constituents using a simulated quarterly sampling frequency, and matched about 46 percent of the significant single-period trends identified using monthly data and about 65 percent of the analyses that indicated no trend using the monthly data.

Missouri↗

Evaluating the impact of irrigation on surface water – groundwater interaction and stream temperature in an agricultural watershed

Changes in groundwater discharge to streams caused by irrigation practices can influence stream temperature. Observations along two currently flood-irrigated reaches in the 640-square-kilometer upper Smith River watershed, an important agricultural and recreational fishing area in west-central Montana, showed a downstream temperature decrease resulting from groundwater discharge to the stream. A watershed-scale coupled surface water and groundwater flow model was used to examine changes in streamflow, groundwater discharge to the stream and stream temperature resulting from irrigation practices. The upper Smith River watershed was used to develop the model framework including watershed climate, topography, hydrography, vegetation, soil properties and current irrigation practices. Model results were used to compare watershed streamflow, groundwater recharge, and groundwater discharge to the stream for three scenarios: natural, pre-irrigation conditions (PreIrr); current irrigation practices involving mainly stream diversion for flood and sprinkler irrigation (IrrCurrent); and a hypothetical scenario with only groundwater supplying sprinkler irrigation (IrrGW). Irrigation increased groundwater recharge relative to natural PreIrr conditions because not all applied water was removed by crop evapotranspiration. Groundwater storage and groundwater discharge to the stream increased relative to natural PreIrr conditions when the source of irrigation water was mainly stream diversion as in the IrrCurrent scenario. The hypothetical IrrGW scenario, in which groundwater withdrawals were the sole source of irrigation water, resulted in widespread lowering of the water table and associated decreases in groundwater storage and groundwater discharge to the stream. A mixing analysis using model predicted groundwater discharge along the reaches suggests that stream diversion and flood irrigation, represented in the IrrCurrent scenario, has led to cooling of stream temperatures relative to natural PreIrr conditions improving fish thermal habitat. However, the decrease in groundwater discharge in the IrrGW scenario resulting from large-scale groundwater withdrawal for irrigation led to warmer than natural stream temperatures and possible degradation of fish habitat.

Montana↗

Changes in reproductive biomarkers in an endangered fish species (bonytail chub, Gila elegans) exposed to low levels of organic wastewater compounds in a controlled experiment

In arid regions of the southwestern United States, municipal wastewater treatment plants commonly discharge treated effluent directly into streams that would otherwise be dry most of the year. A better understanding is needed of how effluent-dependent waters (EDWs) differ from more natural aquatic ecosystems and the ecological effect of low levels of environmentally persistent organic wastewater compounds (OWCs) with distance from the pollutant source. In a controlled experiment, we found 26 compounds common to municipal effluent in treatment raceways all at concentrations <1.0 μg/L. Male bonytail chub (Gila elegans) in tanks containing municipal effluent had significantly lower levels of 11-ketotestosterone (p = 0.021) yet higher levels of 17β-estradiol (p = 0.002) and vitellogenin (p = 0.036) compared to control male fish. Female bonytail chub in treatment tanks had significantly lower concentrations of 17β-estradiol than control females (p = 0.001). The normally inverse relationship between primary male and female sex hormones, expected in un-impaired fish, was greatly decreased in treatment (r = 0.00) versus control (r = −0.66) female fish. We found a similar, but not as significant, trend between treatment (r = −0.45) and control (r = −0.82) male fish. Measures of fish condition showed no significant differences between male or female fish housed in effluent or clean water. Inter-sex condition did not occur and testicular and ovarian cells appeared normal for the respective developmental stage and we observed no morphological alteration in fish. The population-level impacts of these findings are uncertain. Studies examining the long-term, generational and behavioral effects to aquatic organisms chronically exposed to low levels of OWC mixtures are needed.

Aquatic Toxicology↗

Hydrogeology, Water Chemistry, and Factors Affecting the Transport of Contaminants in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

Ground-water chemistry in the zone of contribution of a public-supply well in Modesto, California, was studied by the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program's topical team for Transport of Anthropogenic and Natural Contaminants (TANC) to supply wells. Twenty-three monitoring wells were installed in Modesto to record baseline hydraulic information and to collect water-quality samples. The monitoring wells were divided into four categories that represent the chemistry of different depths and volumes of the aquifer: (1) water-table wells were screened between 8.5 and 11.7 m (meter) (28 and 38.5 ft [foot]) below land surface (bls) and were within 5 m (16 ft) of the water table; (2) shallow wells were screened between 29 and 35 m (95 and 115 ft) bls; (3) intermediate wells were screened between 50.6 and 65.5 m (166 and 215 ft) bls; and (4) deep wells are screened between 100 to 106 m (328 and 348 ft) bls. Inorganic, organic, isotope, and age-dating tracers were used to characterize the geochemical conditions in the aquifer and understand the mechanisms of mobilization and movement of selected constituents from source areas to a public-supply well. The ground-water system within the study area has been significantly altered by human activities. Water levels in monitoring wells indicated that horizontal movement of ground water was generally from the agricultural areas in the northeast towards a regional water-level depression within the city in the southwest. However, intensive pumping and irrigation recharge in the study area has caused large quantities of ground water to move vertically downward within the regional and local flow systems. Analysis of age tracers indicated that ground-water age varied from recent recharge at the water table to more than 1,000 years in the deep part of the aquifer. The mean age of shallow ground water was determined to be between 30 and 40 years. Intermediate ground water was determined to be a mixture of modern (Post-1950) and old (Pre-1950) ground water. As a result, concentrations of age tracers were detectable but diluted by older ground water. Deep ground water generally represented water that was recharged under natural conditions and therefore had much older ages. Ground water reaching the public-supply well was a mixture of older intermediate and deep ground water and young shallow ground water that has been anthropogenically-influenced to a greater extent than intermediate ground water. Uranium and nitrate pose the most significant threat to the quality of water discharged from the public-supply well. Although pesticides and VOCs were present in ground water from the public-supply well and monitoring wells, currently concentrations of these contaminants are generally less than one-hundredth the concentration of drinking water standards. In contrast, both uranium and nitrate were above half the concentration of drinking water standards for public-supply well samples, and were above drinking water standards for several water-table and shallow monitoring wells. Shallow ground water contributes roughly 20 percent of the total flow to the public-supply well and was the entry point of most contaminants reaching the public-supply well. Naturally-occurring uranium, which is commonly adsorbed to aquifer sediments, was mobilized by oxygen-rich, high-alkalinity water, causing concentrations in some monitoring wells to be above the drinking-water standard of 30 ug/L (microgram per liter). Adsorption experiments, sediment extractions, and uranium isotopes indicated uranium in water-table and shallow ground water was leached from aquifer sediments. Uranium is strongly correlated to bicarbonate concentrations (as measured by alkalinity) in ground water. Bicarbonate can effectively limit uranium adsorption to sediments. As a result, continued downward movement of high-alkalinity, oxygen-rich ground water will likely lead to larger portions of the aquifer having

Scientific Investigations Report↗

Concentration-discharge relations and transient metal loads reveal spatiotemporal variability in solute-generation mechanisms in a mine-affected watershed

Concentration-discharge (CQ) relations are commonly used to understand geochemical and hydrologic controls on the generation of solutes in watersheds. Despite the widespread application of CQ relations, this technique has been infrequently applied to acid mine drainage (AMD) sites, but the CQ framework may allow mechanistic understanding of remedial outcomes such as impoundment of water within underground mines. Results of CQ analyses and changes in metal loads in an AMD affected watershed in Colorado, USA indicate that dissolved loads increased at many individual locations following water impoundment within mine workings. Although increased loads were observed at most individual locations, these increases were offset by a large decrease in loading from the largest mine. A loading analysis that included data from an instream monitoring location showed a statistically significant decrease in Fe and Zn after bulkhead emplacement, indicating a net positive effect of bulkheads. Streams generally displayed dilution CQ patterns whereas mines and springs showed either flushing or chemostatic patterns prior to bulkheading, which transitioned to chemostatic patterns following bulkheading, indicating a transition from dynamic to equilibrium geochemical processes. Saturation indices for sulfide and secondary minerals indicated that mines and springs were near equilibrium for phases including schwertmannite, fluorite, and gypsum. Saturation indices vary through time for mines suggesting progressive leaching of sulfide minerals as the mass of available minerals in the mine workings decreases. Together, these diverse analyses provide an integrated understanding of the variability in solute generating processes in this watershed and may inform remediation plans for similarly affected sites by indicating the nature of mineralogic controls on water quality.

Colorado↗

Ground-water quality in Bannock, Bear Lake, Caribou, and part of Power counties, southeastern Idaho

This report provides information about the current quality of ground waters in southeastern Idaho and discusses the natural and manmade environmental controls on that quality. This information will be useful in planning and monitoring the development and use of the ground-water resources of southeastern Idaho. The southeastern corner of Idaho, as described in this report, encompasses an area of about 4,000 mil in Bannock, Bear Lake, Caribou, and part of Power Counties. The popu- lation of the area in 1975, based on best estimates by the Idaho Division of Budget, Policy Planning, and Coordination (1976) was 75,200. About 80 percent of the population is in and near the city of Pocatello, which is the second largest population center in the State. Pocatello's economy depends largely on manufacturing and industrial processing, which includes chemicalfertilizer plants. The econ- omy in the rural areas depends largely on agriculture--both dry and irrigated farming are practiced. Mining is important and expected to dominate the economy in the eastcentral part of the area in the future. Natural resources include phosphate ore, which makes up about 35 percent of the U.S. reserves (U.S. Department of Interior and U.S. Department of Agriculture, 1977); ground water, which mostly underlies the several intermontane valleys that dissect the area; and hot springs, which indicate that geothermal energy sources may underlie part of the area. Also, current (1978) speculation is that petroleum reserves may be present in the vicinity of Bear Lake. Development of more sprink- ler-irrigated lands, increases in population, and growth of phosphate mining are expected to place stress on the ground-water resources, both in quality and quantity. The purpose of this report is to present the results of a study whose primary objectives were (1) to provide current waterquality data representative of the water in several different aquifers (water- bearing formations) in the study area, and (2) to relate these data to natural and manmade environmental controls. The wells sampled during this study establish a quasi-network, which could be resampled in the future to document and analyze changes (if any) in ground-water quality. Based on this information, planners and water managers could better understand the causeand-effect relations controlling water quality and could better manage land and water-resource development. The report is designed for ease of reading and presentation. It uses maps, tables, and abbreviated text to describe geology, hydrology, and ground-water quality and how they are interrelated. Some practical ways for improving water quality are discussed for the benefit of individual water users. The field data collected in making the study are contained in the Data Section of this report. The authors gratefully acknowledge the many individual well owners, municipal officials, and private industries that provided well information and allowed access to their properties and collection of water samples. Without their help, this work could not have been done. Water samples were collected at 103 well sites. Waterlevel measurements were made at 98 of these sites during July, August, and September of 1976. This study was made by the U.S. Geological Survey in cooperation with the Idaho Department of Water Resources. A similar study is being made (1978) in north Idaho. Other studies are planned, specifically to obtain ground-water-quality data in areas where land and water-resource development is expected or accelerating.

Idaho↗

Trace elements and consequent ecological risks in mining- influenced streams of Appalachia

Appalachian coal surface mines fracture geologic materials, causing release of both major ions and trace elements to water via accelerated weathering. When elevated above natural background, trace elements in streams may produce adverse effects to biota via direct exposure from water and sediment and via dietary exposure in food sources. Other studies have found elevated water concentrations of multiple trace elements in Appalachia's mining-influenced streams. Excepting Se, trace-element concentrations in abiotic and biotic media of Appalachian mining-influenced streams are less well-known. We analyzed environmental media of headwater streams receiving alkaline waters from Appalachian coal mines for eight trace elements (Al, As, Cd, Cu, Ni, Sr, V, and Zn) and assessed potential consequent ecological risks. Streamwater, particulate media (sediment, biofilm, leaf detritus) and benthic macroinvertebrates (primary consumers, secondary consumers, crayfish) were sampled from six mining-influenced and three reference streams during low-flow conditions in two seasons. Dissolved Cu, Ni, and Sr were higher in mining-influenced streams than in reference streams; whereas Ni, Sr, and Zn in fine sediments and Ni in macroinvertebrates were also elevated relative to reference-stream levels in samples from mining-influenced streams. Seasonal ratios of mining-influenced stream concentrations to maximum concentrations in reference streams also demonstrated mining-influenced increases for several elements in multiple media. In most media, concentrations of several elements including Ni were correlated positively. All water-column dissolved concentrations were below protective levels, but fine-sediment concentrations of Ni approached or exceeded threshold-effect concentrations in several streams. Further study is warranted for several elements (Cd, Ni, and Zn in biofilms, and V in macroinvertebrates), which approached or exceeded previously established dietary-risk levels.

Virginia, West Virginia↗

A history of trade routes and water-level regulation on waterways in Voyageurs National Park, Minnesota, USA

Unlike most national parks, main access to Voyageurs National Park is by boat. This remote system of interconnected waterways along the USA-Canada border was an important transportation route for thousands of years of American Indian occupation, leading up to and including the trade route of the voyageurs, or French-Canadian fur traders from around 1680 to 1870. The Ojibwe people collaborated with the voyageurs and the two cultures developed a trade network that continued to rely on these waterways. By the mid-1800s, European fashion changed, and the fur trade dwindled while the Ojibwe remained tied to the land and waters. The complexity of the waterways increased with the installation of dams on two of the natural lakes in the early 1900s. Modern water levels have affected—and in some cases destabilized—vulnerable landforms within the past century. The knowledge of these effects can be used by resource managers to weigh the consequences of hydrologic manipulation in Voyageurs National Park.

Minnesota↗

Ground-Water Age and its Water-Management Implications, Cook Inlet Basin, Alaska

The Cook Inlet Basin encompasses 39,325 square miles in south-central Alaska. Approximately 350,000 people, more than half of Alaska?s population, reside in the basin, mostly in the Anchorage area. However, rapid growth is occurring in the Matanuska?Susitna and Kenai Peninsula Boroughs to the north and south of Anchorage. Ground-water resources provide about one-third of the water used for domestic, commercial and industrial purposes in the Anchorage metropolitan area and are the sole sources of water for industries and residents outside Anchorage. In 1997, a study of the Cook Inlet Basin was begun as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. Samples of ground water were collected from 35 existing wells in unconsolidated glacial and alluvial aquifers during 1999 to determine the regional quality of ground water beneath about 790 mi2 of developed land and to gain a better understanding of the natural and human factors that affect the water quality (Glass, 2001). Of the 35 wells sampled, 31 had water analyzed for atmospherically derived substances to determine the ground water?s travel time from its point of recharge to its point of use or discharge?also known as ground-water age. Ground water moves slowly from its point of recharge to its point of use or discharge. This water starts as rain and melting snow that soak into the ground as recharge. In the Matanuska?Susitna, Anchorage, and Kenai Peninsula areas, ground water generally moves from near the mountain fronts toward Cook Inlet or the major rivers. Much of the water pumped by domestic and public-supply wells may have traveled less than 10 miles, and the trip may have taken as short a time as a few days or as long as several decades. This ground water is vulnerable to contamination from the land surface, and many contaminants in the water would follow the same paths and have similar travel times from recharge areas to points of use as the chemical substances analyzed in this study. The effects of contamination may not be seen for several years after a contaminant is introduced into the ground-water system. Many contaminants could make the water unsuitable for drinking for many years, even in concentrations too low to detect without expensive chemical tests. The travel time of a chemically conservative substance depends primarily on the velocity of ground water through the aquifer, which in turn depends on the hydrologic characteristics of the aquifer system.

Fact Sheet↗

Streamflow and sediment dynamics of the Middle Rio Grande Valley, New Mexico, in the context of cottonwood recruitment

The cottonwood gallery forests of the Middle Rio Grande floodplain in New Mexico provide important habitats for birds and other animals. Over the last century, these forests have changed significantly due to invasion of exotics such as salt cedar and Russian olive, which compete with native cottonwoods, and changes in water use both in the valley and upstream. To successfully germinate and establish, cottonwoods require an adequate water supply, abundant sunlight, and bare, litter-free substrate. Native cottonwoods are adapted to a natural snowmelt hydrograph characterized by spring floods in late May or early June and gradually receding streamflows throughout the remainder of the summer. The natural streamflow pattern has been significantly modified by water management in the Rio Grande basin. The modified pattern is less conducive to establishment of cottonwoods than the natural pattern. In addition, exotic species now compete with native cottonwoods, and the modified flow pattern may favor these exotics. The overall objective of this study was to investigate the possibility of enhancing cottonwood establishment and recruitment along the Middle Rio Grande through streamflow manipulation and reservoir releases. The work integrates concepts of cottonwood establishment, water resources management, and river morphology, and investigates how water management might be used to preserve and enhance cottonwood gallery forests along the river. Specific objectives of the work reported herein were to: (1) develop a technique to calculate flows that will produce channel characteristics necessary to restore and sustain cottonwood gallery forests; (2) develop a model to determine a flow pattern, or sequence of flows, that will improve the potential for cottonwood establishment and recruitment; and (3) determine if the water resources can be managed to produce the desired channel characteristics and flow pattern identified in (1) and (2).

Report↗

Ground-water supplies in the Murfreesboro area, Tennessee

Ground water occurs in the Murfreesboro area in solution openings in the otherwise dense paleozoic limestones that underlie most of central Tennessee. Test drilling based on conceptual models of ground-water occurrence in carbonate-rock aquifers indicate that multimillion-gallon-per-day supplies could be developed from strategically located production wells in the Shiloh and Overall Creek localities. The Shiloh locality which encompasses an elongated synclinal depression in the bedrock has the potential to supply 5 to 8 million gallons per day. The Overall Creek locality which straddles a joint-oriented lineament has the potential to supply 3 to 6 million gallons per day. Some local springs could be used as a supplemental source of potable water, but storage facilities would be needed to offset poorly sustained flows during dry periods. An exception is Fox Camp Spring which appears to be a natural well. The quality of ground water in the Murfreesboro area is typically hard, moderately mineralized and moderately to highly alkaline. Although the shallowest aquifers are subject to bacterial contamination from the land surface, aquifers beneath a depth of 100 feet are prone to yield potable water. (Woodard-USGS)

Tennessee↗

Estimating annual high-flow statistics and monthly and seasonal low-flow statistics for ungaged sites on streams in Alaska and conterminous basins in Canada

Methods for estimating daily mean flow-duration statistics for seven regions in Alaska and low-flow frequencies for one region, southeastern Alaska, were developed from daily mean discharges for streamflow-gaging stations in Alaska and conterminous basins in Canada. The 15-, 10-, 9-, 8-, 7-, 6-, 5-, 4-, 3-, 2-, and 1-percent duration flows were computed for the October-through-September water year for 222 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the individual months of July, August, and September for 226 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the season July-through-September for 65 stations in southeastern Alaska. The 7-day, 10-year and 7-day, 2-year low-flow frequencies for the season July-through-September were computed for 65 stations for most of southeastern Alaska. Low-flow analyses were limited to particular months or seasons in order to omit winter low flows, when ice effects reduce the quality of the records and validity of statistical assumptions. Regression equations for estimating the selected high-flow and low-flow statistics for the selected months and seasons for ungaged sites were developed from an ordinary-least-squares regression model using basin characteristics as independent variables. Drainage area and precipitation were significant explanatory variables for high flows, and drainage area, precipitation, mean basin elevation, and area of glaciers were significant explanatory variables for low flows. The estimating equations can be used at ungaged sites in Alaska and conterminous basins in Canada where streamflow regulation, streamflow diversion, urbanization, and natural damming and releasing of water do not affect the streamflow data for the given month or season. Standard errors of estimate ranged from 15 to 56 percent for high-duration flow statistics, 25 to greater than 500 percent for monthly low-duration flow statistics, 32 to 66 percent for seasonal low-duration flow statistics, and 53 to 64 percent for low-flow frequency statistics.

Water-Resources Investigations Report↗