Natural attenuation of chlorinated solvent ground-water plumes discharging into wetlands
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Scientific Investigations Report↗
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Natural radium and radon tracers to quantify water exchange and movement in reservoirs
Radon and radium isotopes are routinely used to quantify exchange rates between different hydrologic reservoirs. Since their recognition as oceanic tracers in the 1960s, both radon and radium have been used to examine processes such as air-sea exchange, deep oceanic mixing, benthic inputs, and many others. Recently, the application of radon-222 and the radium-quartet (223,224,226,228Ra) as coastal tracers has seen a revelation with the growing interest in coastal groundwater dynamics. The enrichment of these isotopes in benthic fluids including groundwater makes both radium and radon ideal tracers of coastal benthic processes (e.g. submarine groundwater discharge). In this chapter we review traditional and recent advances in the application of radon and radium isotopes to understand mixing and exchange between various hydrologic reservoirs, specifically: (1) atmosphere and ocean, (2) deep and shallow oceanic water masses, (3) coastal groundwater/benthic pore waters and surface ocean, and (4) aquifer-lakes. While the isotopes themselves and their distribution in the environment provide qualitative information about the exchange processes, it is mixing/exchange and transport models for these isotopes that provide specific quantitative information about these processes. Brief introductions of these models and mixing parameters are provided for both historical and more recent studies.
Book chapter↗
Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Determination of whole-water recoverable arsenic, boron, and vanadium using inductively coupled plasma-mass spectrometry
Analysis of in-bottle digestate by using the inductively coupled plasma?mass spectrometric (ICP?MS) method has been expanded to include arsenic, boron, and vanadium. Whole-water samples are digested by using either the hydrochloric acid in-bottle digestion procedure or the nitric acid in-bottle digestion procedure. When the hydrochloric acid in-bottle digestion procedure is used, chloride must be removed from the digestate by subboiling evaporation before arsenic and vanadium can be accurately determined. Method detection limits for these elements are now 10 to 100 times lower than U.S. Geological Survey (USGS) methods using hydride generation? atomic absorption spectrophotometry (HG? AAS) and inductively coupled plasma? atomic emission spectrometry (ICP?AES), thus providing lower variability at ambient concentrations. The bias and variability of the methods were determined by using results from spike recoveries, standard reference materials, and validation samples. Spike recoveries in reagent-water, surface-water, ground-water, and whole-water recoverable matrices averaged 90 percent for seven replicates; spike recoveries were biased from 25 to 35 percent low for the ground-water matrix because of the abnormally high iron concentration. Results for reference material were within one standard deviation of the most probable value. There was no significant difference between the results from ICP?MS and HG?AAS or ICP?AES methods for the natural whole-water samples that were analyzed.
Open-File Report↗
Table Rock Lake Water-Clarity Assessment Using Landsat Thematic Mapper Satellite Data
Water quality of Table Rock Lake in southwestern Missouri is assessed using Landsat Thematic Mapper satellite data. A pilot study uses multidate satellite image scenes in conjunction with physical measurements of secchi disk transparency collected by the Lakes of Missouri Volunteer Program to construct a regression model used to estimate water clarity. The natural log of secchi disk transparency is the dependent variable in the regression and the independent variables are Thematic Mapper band 1 (blue) reflectance and a ratio of the band 1 and band 3 (red) reflectance. The regression model can be used to reliably predict water clarity anywhere within the lake. A pixel-level lake map of predicted water clarity or computed trophic state can be produced from the model output. Information derived from this model can be used by water-resource managers to assess water quality and evaluate effects of changes in the watershed on water quality.
Scientific Investigations Report↗
Water resources of the Batavia Kill basin at Windham, Greene County, New York
The water resources of a 27.6-square-mile section of the Batavia Kill Basin near the village of Windham, N.Y., which has undergone substantial development, were evaluated. The evaluation entailed (1) estimation of the magnitude and distribution of several hydrologic components, including recharge, (2) measurement of discharge and chemical quality of the Batavia Kill and selected tributaries, (3) analysis of ground-water flow and chemistry, and (4) a conceptualization of the ground-water flow system. The region consists of deeply dissected, relatively flat-lying, clastic sedimentary sequences variably overlain by as much as 120 feet of glacial deposits. The types of bedrock fractures and their distribution in the Batavia Kill valley are consistent with valley stress-relief characteristics. Till predominates in the uplands, and stratified drift typically dominates within the valley of the Batavia Kill and the lower section of its largest tributary valley (Mitchell Hollow). Fractured bedrock is the most commonly used water source within the study area. The areas of highest yielding bedrock generally are with valleys, where the shallow fractures are saturated. Stratified-drift aquifers are also limited to the largest valleys; the greatest saturated thicknesses are in the Batavia Kill valley at Windham. A conceptual model of ground-water flow within the study areas suggests that the zones of most active flow are shallow fractured bedrock in upland areas and the shallow stratified drift in the largest valleys. The hydrogeologic system has been altered by development; major effects include (1) chemical alteration of natural ground-water and surface-water quality by point- and nonpoint-source contaminants, (2) hydraulic interconnection of other-wise isolated bedrock fractures by wellbores, and (3) drawdowns in wells within the Batavia Kill valley by pumping from the bedrock aquifer. Water resource development of the most promising unconsolidated aquifer beneath Windham may be precluded by the potential for contamination by leachate from an abandoned landfill, road-salt stockpiles, and domestic septic systems in the area.
New York↗
Hydrology and water quality of Shell Lake, Washburn County, Wisconsin, with special emphasis on the effects of diversion and changes in water level on the water quality of a shallow terminal lake
Shell Lake is a relatively shallow terminal lake (tributaries but no outlets) in northwestern Wisconsin that has experienced approximately 10 feet (ft) of water-level fluctuation over more than 70 years of record and extensive flooding of nearshore areas starting in the early 2000s. The City of Shell Lake (City) received a permit from the Wisconsin Department of Natural Resources in 2002 to divert water from the lake to a nearby river in order to lower water levels and reduce flooding. Previous studies suggested that water-level fluctuations were driven by long-term cycles in precipitation, evaporation, and runoff, although questions about the lake’s connection with the groundwater system remained. The permit required that the City evaluate assumptions about lake/groundwater interactions made in previous studies and evaluate the effects of the water diversion on water levels in Shell Lake and other nearby lakes. Therefore, a cooperative study between the City and U.S. Geological Survey (USGS) was initiated to improve the understanding of the hydrogeology of the area and evaluate potential effects of the diversion on water levels in Shell Lake, the surrounding groundwater system, and nearby lakes. Concerns over deteriorating water quality in the lake, possibly associated with changes in water level, prompted an additional cooperative project between the City and the USGS to evaluate efeffects of changes in nutrient loading associated with changes in water levels on the water quality of Shell Lake. Numerical models were used to evaluate how the hydrology and water quality responded to diversion of water from the lake and historical changes in the watershed. The groundwater-flow model MODFLOW was used to simulate groundwater movement in the area around Shell Lake, including groundwater/surface-water interactions. Simulated results from the MODFLOW model indicate that groundwater flows generally northward in the area around Shell Lake, with flow locally converging toward the lake. Total groundwater inflow to Shell Lake is small (approximately 5 percent of the water budget) compared with water entering the lake from precipitation (83 percent) and surface-water runoff (13 percent). The MODFLOW model also was used to simulate average annual hydrologic conditions from 1949 to 2009, including effects of the removal of 3 billion gallons of water during 2003–5. The maximum decline in simulated average annual water levels for Shell Lake due to the diversion alone was 3.3 ft at the end of the diversion process in 2005. Model simulations also indicate that although water level continued to decline through 2009 in response to local weather patterns (local drought), the effects of the diversion decreased after the diversion ceased; that is, after 4 years of recovery (2006–9), drawdown attributable to the diversion alone decreased by about 0.6 ft because of increased groundwater inflow and decreased lake-water outflow to groundwater caused by the artificially lower lake level. A delayed response in drawdown of less than 0.5 ft was transmitted through the groundwater-flow system to upgradient lakes. This relatively small effect on upgradient lakes is attributed in part to extensive layers of shallow clay that limit lake/groundwater interaction in the area. Data collected in the lake indicated that Shell Lake is polymictic (characterized by frequent deep mixing) and that its productivity is limited by the amount of phosphorus in the lake. The lake was typically classified as oligotrophic-mesotrophic in June, mesotrophic in July, and mesotrophic-eutrophic in August. In polymictic lakes like Shell Lake, phosphorus released from the sediments is not trapped near the bottom of the lake but is intermittently released to the shallow water, resulting in deteriorating water quality as summer progresses. Because the productivity of Shell Lake is limited by phosphorus, the sources of phosphorus to the lake were quantified, and the response in water quality to changes in phosphorus inputs were evaluated by means of eutrophication models. During 2009, the total input of phosphorus to Shell Lake was 1,730 pounds (lb), of which 1,320 lb came from external sources (76 percent) and 414 lb came from internal loading from sediments in the lake (24 percent). The largest external source was from surface-water runoff, which delivered about 52 percent of the total phosphorus load compared with about 13 percent of the water input. The second largest source was from precipitation (wetfall and dryfall), which delivered 19 percent of the load compared to about 83 percent of the water input. Contributions from septic systems and groundwater accounted for about 3 and 2 percent, respectively. Increased runoff raises water levels in the lake but does not necessarily increase phosphorus loading because phosphorus concentrations in the tributaries decline during increased flow, possibly because of shorter retention times in upstream wetlands. Phosphorus loading to the lake in 2009 represented what occurred after a series of dry years; therefore, this information was combined with data from 2011, a wet year, to estimate phosphorus loading during a range of hydrologic conditions by estimating loading from each component of the phosphorus budget for each year from 1949 to 2011. Comparisons of historical water-quality records with historical water levels and applications of a hydrodynamic model (Dynamic Lake Model, DLM) and empirical eutrophication models were used to understand how changes in water level and the coinciding changes in phosphorus loading affect the water quality of Shell Lake. DLM simulations indicate that large changes in water level (approximately 10 ft) affect the persistence of stratification in the lake. During periods with low water levels, the lake is a well-mixed, polymictic system, with water quality degrading slightly as summer progresses. During periods with high water levels, the lake is more stratified, and phosphorus from internal loading is trapped in the hypolimnion and released later in summer, which results in more extreme seasonality in water quality and better clarity in early summer. Results of eutrophication model simulations using a range in external phosphorus inputs illustrate how water quality in Shell Lake (phosphorus and chlorophyll a concentrations and Secchi depths) responds to changes in external phosphorus loading. Results indicate that a 50-percent reduction in external loading from that measured in 2009 would be required to change phosphorus concentrations from 0.018 milligram per liter (mg/L) (measured in 2009) to 0.012 mg/L (estimated for the mid-1800s from analysis of diatoms in sediment cores). Such reductions in phosphorus loading cannot be accomplished by targeting septic systems or internal loading alone because septic systems contribute only about 3 percent of the phosphorus input to the lake, and internal loading from the sediments of Shell Lake contributes only about 25 percent of phosphorus input. Complete elimination of phosphorus from septic systems and internal loading would decrease the phosphorus concentrations in the lake by 0.003–0.004 mg/L. Therefore, reducing phosphorus concentration in the lake more than by 0.004 mg/L requires decreasing phosphorus loading from surface-water contributions, primarily runoff to the lake. Reconstructed changes in water quality from 1860 to 2010, based on changes in the diatom communities archived in the sediments and eutrophication model simulations, suggest that anthropogenic changes in the watershed (sawmill construction in 1881; the establishment of the village of Shell Lake; and land-use changes in the 1920s, including increased agriculture) had a much larger effect on water quality than the natural changes associated with fluctuations in water level. Although the effects of natural changes in water level on water quality appear to be small, changes in water level do have a modest effect on water quality, primarily manifested as small improvements during higher water levels. Fluctuations in water level, however, have a larger effect on the seasonality of water-quality patterns, with better water quality, especially increased Secchi depths, in early summer during years with high water levels.
Wisconsin↗
Effects of brush management on the hydrologic budget and water quality in and adjacent to Honey Creek State Natural Area, Comal County, Texas, 2001-10
The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Natural Resources Conservation Service, the Edwards Region Grazing Lands Conservation Initiative, the Texas State Soil and Water Conservation Board, the San Antonio River Authority, the Edwards Aquifer Authority, Texas Parks and Wildlife, the Guadalupe Blanco River Authority, and the San Antonio Water System, evaluated the hydrologic effects of ashe juniper ( Juniperus ashei ) removal as a brush management conservation practice in and adjacent to the Honey Creek State Natural Area in Comal County, Tex. By removing the ashe juniper and allowing native grasses to reestablish in the area as a brush management conservation practice, the hydrology in the watershed might change. Using a simplified mass balance approach of the hydrologic cycle, the incoming rainfall was distributed to surface water runoff, evapotranspiration, or groundwater recharge. After hydrologic data were collected in adjacent watersheds for 3 years, brush management occurred on the treatment watershed while the reference watershed was left in its original condition. Hydrologic data were collected for another 6 years. Hydrologic data include rainfall, streamflow, evapotranspiration, and water quality. Groundwater recharge was not directly measured but potential groundwater recharge was calculated using a simplified mass balance approach. The resulting hydrologic datasets were examined for differences between the watersheds and between pre- and post-treatment periods to assess the effects of brush management. The streamflow to rainfall relation (expressed as event unit runoff to event rainfall relation) did not change between the watersheds during pre- and post-treatment periods. The daily evapotranspiration rates at the reference watershed and treatment watershed sites exhibited a seasonal cycle during the pre- and post-treatment periods, with intra- and interannual variability. Statistical analyses indicate the mean difference in daily evapotranspiration rates between the two watershed sites is greater during the post-treatment than the pre-treatment period. Average annual rainfall, streamflow, evapotranspiration, and potential groundwater-recharge conditions were incorporated into a single hydrologic budget (expressed as a percentage of the average annual rainfall) applied to each watershed before and after treatment to evaluate the effects of brush management. During the post-treatment period, the percent average annual unit runoff in the reference watershed was similar to that in the treatment watershed, however, the difference in percentages of average annual evapotranspiration and potential groundwater recharge were more appreciable between the reference and treatment watersheds than during the pre-treatment period. Using graphical comparisons, no notable differences in major ion or nutrient concentrations were found between samples collected at the reference watershed (site 1C) and treatment watershed (site 2C) during pre- and post-treatment periods. Suspended-sediment loads were calculated from samples collected at sites 1C and 2T. The relation between suspended-sediment loads and streamflow calculated from samples collected from sites 1C and 2T did not exhibit a statistically significant difference during the pre-treatment period, whereas during the post-treatment period, relation between suspended-sediment loads and streamflow did exhibit a statistically significant difference. The suspended-sediment load to streamflow relations indicate that for the same streamflow, the suspended-sediment loads calculated from site 2T were generally less than suspended-sediment loads calculated from site 1C during the post-treatment period.
Texas↗
Geology and ground-water resources of Rock County, Wisconsin
Rock County is in south-central Wisconsin adjacent to the Illinois State line. The county has an area of about 723 square miles and had a population of about 113,000 in 1957 ; it is one of the leading agricultural and industrial counties in the State. The total annual precipitation averages about 32 inches, and the mean annual temperature is about 48 ? F. Land-surface altitudes are generally between 800 and 00 feet, but range from 731 feet, where the Rock River flows into Illinois, to above 1,080 feet, at several places in the northwestern part of the county. The northern part of Rock County consists of the hills and kettles of a terminal moraine which slopes southward to a flat, undissected outwash plain. The southeastern part of the county is an area of gentle slopes, whereas the southwestern part consists of steep-sided valleys and ridges. Rock County is within the drainage basin of the Rock River, which flows southward through the center of the county. The western and southwestern parts of ,the county are drained by the Sugar River und Coon Creek, both of which flow into the Pecatonica River in Illinois and thence into the Rock River. The southeastern part of the county is drained by Turtle Creek, which also flows into Illinois before joining the Rock River. Nearly all the lakes and ponds are in the northern one-third of the county, the area of most recent glaciation. The aquifers in Rock County are of sedimentary origin and include deeply buried sandstones, shales, and dolomites of the Upper Cambrian series. This series overlies crystalline rocks of Precambrian age and supplies water to all the cities and villages in the county. The St. Peter sandstone of Ordovician age underlies all Rock County except where the formation has been removed by erosion in the Rock and Sugar River valleys, and perhaps in Coon Creek valley. The St. Peter sandstone is the principal source of water for domestic, stock, and small industrial wells in the western half of the county. This sandstone also yields some water to uncased wells that tap the deeper rocks of the Upper Cambrian series. East of the Rock River the Platteville, Decorah, and Galena formations undifferentiated, or Platteville-Galena unit, is the principal source of water for domestic and stock wells. Unconsolidated deposits of glacial origin cover most of Rock County and supply water to many small wells. In the outwash deposits along the Rock River, wells of extremely high capacity have been developed for industrial and municipal use. The most significant feature of the bedrock surface in Rock County is the ancestral Rock River valley, which has been filled with glacial outwash to a depth of at least 396 feet below the present land surface. East of the buried valley the bedrock has a fiat, relatively undissected surface. West of the valley the bedrock surface is rugged and greatly dissected. Ground water in Rock County occurs under both water-table and artesian conditions; however, because of the interconnection and close relation of all ground water in the county, the entire system is considered to be a single groundwater body whose surface may be represented by one piezometric map. Recharge occurs locally, throughout the county. Nearly all recharge is derived directly from precipitation that percolates downward to become a part of the groundwater body. Natural movement of water in the consolidated water-bearing units is generally toward the buried Rock and Sugar River valleys. Movement of water in the sandstones of Cambrian age was calculated to be about 44 million gallons a day toward the Rock River. Discharge from wells in Rock County in 1957 was about 23 million gallons a day. Nearly 90 percent of this water was drawn from the area along the Rock River. Drilled wells, most of which were drilled by the cable-tool method, range in diameter from 3 to 26 inches, and in depth from 46 to 1,225 feet. Driven wells in alluvium and glacial drift are usually 1? to 2? in
Wisconsin↗
Scoping decision-maker needs and science availability to support regional natural capital accounting in the U.S. Colorado River Basin
Natural capital accounting has the potential to yield important policy insights at multiple scales, but there remains a disconnect between regional-scale natural capital accounts and their use for informing policy. In this paper, we propose a roadmap that could lead to the creation of policy-relevant regional accounts, with steps split across an initial scoping phase and a subsequent development phase. We demonstrate the scoping steps in action with an application to the Colorado River Basin (“Basin”), a large watershed in the southwestern United States (U.S.) that has faced aridification and substantial high-profile tradeoffs around the use of its water and other natural resources. Drawing on prior U.S. Geological Survey science co-production efforts, we conducted a series of eight discussion sessions with 41 scientists and science representatives whose work is relevant to Basin water, riparian and riverine ecosystems, upland ecosystems and energy and minerals. We summarise participants' thoughts on key topics and economic linkages, their insights and questions of interest and their recommendations on existing scientific data sources and gaps. We evaluate the suitability of the available data for construction of System of Environmental-Economic Accounting (SEEA) Central Framework and SEEA Ecosystem Accounting accounts, including those for land, water, forests, energy and minerals and ecosystems (covering extent, condition and ecosystem services). We present a series of lessons learned during the scoping phase, as well as lessons that could be relevant for future practitioners engaging in the development phase. The information can help guide the development of timely and relevant regional-scale environmental-economic accounts in the U.S. and beyond.
Arizona, California, Colorado, Nevada, New Mexico,↗
Assessment of water availability in the Osage Nation using an integrated hydrologic-flow model
The Osage Nation of northeastern Oklahoma, conterminous with Osage County, covers about 2,900 square miles. The area is primarily rural with 62 percent of the land being native prairie grass, and much of the area is used for cattle ranching and extraction of petroleum and natural gas. Protection of water rights are important to the Osage Nation because of its reliance on cattle ranching and the potential for impairment of water quality by petroleum extraction. Additionally, the potential for future population increases, demands for water from neighboring areas such as the Tulsa metropolitan area, and expansion of petroleum and natural-gas extraction on water resources of this area further the need for the Osage Nation to better understand its water availability. Therefore, the U.S. Geological Survey, in cooperation with the Osage Nation, completed a hydrologic investigation to assess the status and availability of surface-water and groundwater resources in the Osage Nation. A transient integrated hydrologic-flow model was constructed using the U.S. Geological Survey fully integrated hydrologic-flow model called the MODFLOW One-Water Hydrologic Model. The integrated hydrologic-flow model, called the Osage Nation Integrated Hydrologic Model (ONIHM), was constructed and uses an orthogonal grid of 276 rows and 289 columns, and each grid cell measures 1,312.34 feet (ft; 400 meters) per side, with eight variably thick vertical layers that represented the alluvial and bedrock aquifers within the study area, including the alluvial aquifer, the Vamoosa-Ada aquifer, and the minor Pennsylvanian bedrock aquifers, and the confining units. Landscape and groundwater-flow processes were simulated for two periods: (1) the 1950–2014 period from January 1950 through September 2014 and (2) the forecast period from October 2014 through December 2099. The 1950–2014 period ONIHM simulated past conditions using measured or estimated inputs, and the forecast-period ONIHM simulated three separate potential forecast conditions under constant dry, average, or wet climate conditions using calibrated input values from the 1950–2014 period ONIHM. The 1950–2014 period ONIHM was calibrated by linking the Parameter Estimation software (PEST) with the MODFLOW One-Water Hydrologic Model. PEST uses statistical parameter estimation techniques to identify the best set of parameter values to minimize the difference between measured or estimated calibration targets and their simulated equivalent values (residuals). Tikhonov regularization and singular-value decomposition-assist features of PEST were used during the calibration process. The 1950–2014 period ONIHM was calibrated to 713 measured groundwater levels at 195 wells; 95,636 estimated monthly mean groundwater levels at 124 wells; 5,307 measured streamflows at 13 streamgages; and 8,679 simulated mean monthly streamflows at 10 streamgages extracted from a surface-water model by adjusting 231 parameters. The estimated groundwater-level observations and streamflows were included as observations to improve the spatial and temporal density of observation targets during calibration. The best set of parameter values obtained during the calibration process of the 1950–2014 model was then used as the input parameter values for the forecast model simulations. A comparison of the calibration targets to their corresponding simulated values indicated that the model adequately reproduced streamflows and groundwater levels for some streamgages and wells and underestimated streamflows and groundwater levels at other locations. Measured and simulated streamflows correlated adequately with a coefficient of determination of 0.938, as did water levels with a coefficient of determination of 0.795. The 1950–2014 period ONIHM underestimated certain groundwater levels and streamflows, but generally measured or estimated calibration targets correlated well with simulated equivalents, which indicated that the model can adequately simulate the response of the hydrologic system to stresses in the 1950–2014 and forecast periods. In the 1950–2014 period ONIHM, the calibrated mean horizontal hydraulic conductivity for layer 1 alluvial aquifer was 30.7 feet per day, and the seven lower layers had a calibrated mean horizontal hydraulic conductivity of less than 3.3 feet per day. The mean calibrated groundwater-level residual was 16.6 ft, and the mean calibrated streamflow residual of the Arkansas River at Ralston, Oklahoma, streamgage (U.S. Geological Survey station 07152500) was within 6 percent (373 cubic feet per second) of mean measured streamflow for the 1950–2014 period ONIHM. The ONIHM simulated landscape fluxes of precipitation; groundwater applied by irrigation wells; evapotranspiration from precipitation, groundwater, and irrigation; runoff from precipitation; and deep percolation from precipitation. The largest loss of water from the landscape was evapotranspiration from precipitation with a calibrated mean annual outflow of 32 inches (in.): mean annual precipitation was about 36 in. Calibrated mean annual runoff and deep percolation (recharge to the water table) rates were 4.7 inches per year (in/yr) and 0.70 in/yr, respectively, for the 1950–2014 period ONIHM. The calibrated 1950–2014 period ONIHM groundwater fluxes included net farm net recharge (calculated as the difference between the inflow of recharge to the water table and the outflow of evapotranspiration from the water table such that negative values indicate that evapotranspiration from the water table was greater than deep percolation [recharge to the water table] and vice versa). Net farm net recharge was the largest flux from the groundwater system with a mean annual net outflow of 153.4 cubic feet per second. Stream leakage was the largest flux to the groundwater system with a mean annual net inflow of 152.5 cubic feet per second, indicating that, on average, the groundwater/surface-water interaction was a “losing” system where stream water leaked into the subsurface and recharged the water table. Simulated monthly trends demonstrated that net stream leakage was the largest inflow to the groundwater-flow system for 10 of the 12 months; for the other 2 months (January and March), farm net recharge (January) and net storage (March) were the largest inflow to the groundwater-flow system. A saline groundwater interface map was created for the study and compared to the water levels from the final stress period of the 1950–2014 model to identify the presence of fresh/marginal groundwater throughout the study area. Fresh/marginal groundwater was characterized as groundwater with less than 1,500 milligrams per liter of total dissolved solids. Fresh/marginal groundwater thickness ranged from 0 to 438.2 ft within the study area. The thickest regions of fresh/marginal groundwater were in the eastern part of the study area near Sand Creek, Bird Creek, and Hominy Creek and in the Arkansas River alluvial aquifer in the region downstream from the Arkansas River at Ralston, Okla. Like the 1950–2014 model, forecast model results for the landscape indicated that transpiration from precipitation was the largest flux out of the landscape for all three forecasts, constituting 77, 73, and 58 percent of precipitation for the dry, average, and wet forecasts, respectively. The dry and average forecast landscape fluxes demonstrated similar trends and magnitudes, whereas the wet forecast landscape fluxes indicated the largest changes compared to the average forecast fluxes. Most notably, runoff increased from a mean of 1.1 and 1.6 in/yr for the dry and average forecasts, respectively, to 10 in/yr for the wet forecast. Similar changes occurred for the other wet forecast landscape fluxes. The calibrated 1950–2014 period ONIHM simulated three forecasts to assess the effects of potential climatic changes on the hydrologic system from October 2014 to December 2099. The three forecasts simulated theoretical dry, average, and wet conditions using precipitation and potential evapotranspiration datasets from selected years in the calibrated 1950–2014 period ONIHM. Annual precipitation amounts were 26.89, 35.47, and 50.73 in. for the dry, average, and wet forecasts, respectively. Groundwater-flow component forecast results indicated that stream leakage is always a net inflow to the groundwater-flow system for dry, average, and wet conditions, meaning the study area stream network is always predominantly a “losing” regime where stream water infiltrates into the underlying aquifer. Storage was only a net outflow from the groundwater-flow system and indicated a replenishment to groundwater storage that resulted in an increase in groundwater levels only during the wet forecast. Further, these gains in groundwater storage for the wet forecast occurred only during February through June. Mean fresh/marginal groundwater saturated thicknesses were 125 and 126 ft for the dry and average forecast conditions, respectively, and wet forecast average thickness was 145 ft and ranged from 0 to 443 ft. The spatial extents of fresh/marginal groundwater at the end of the dry, average, and wet forecast model periods (December 2099) did not change substantially from the end of the 1950–2014 model period (September 2014).
Kansas, Oklahoma↗
Central Plains Water Science Center bookmark
The U.S. Geological Survey Central Plains Water Science Center, serving the states of Kansas and Nebraska, has collected and interpreted hydrologic information for more than a century. Data collected include streamflow and gage height, reservoir content, water quality and water quantity, suspended sediment, and groundwater levels. Interpretative hydrologic studies are completed on national, regional, statewide, and local levels and cooperatively funded through partnerships with these agencies. The U.S. Geological Survey provides impartial scientific information to describe and understand the health of our ecosystems and environment; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life. These collected data are in the National Water Information System (Kansas: https://dashboard.waterdata.usgs.gov/app/nwd/en/ and Nebraska: https://dashboard.waterdata.usgs.gov/app/nwd/en/ ), and all results are documented in reports that also are online (Kansas: https://www.usgs.gov/centers/kswsc and Nebraska: https://www.usgs.gov/centers/nebraska-water-science-center/publications ).
General Information Product↗
Landscape drivers of dynamic change in water quality of US rivers
Water security is a top concern for social well-being and dramatic changes in the availability of freshwater have occurred as a result of human uses and landscape management. Elevated nutrient loading and perturbations to major ion composition have resulted from human activities and have degraded freshwater resources. This study addresses the emerging nature of stream water quality in the 21st century through analysis of concentrations and trends in a wide variety of constituents in streams and rivers of the U.S. Concentrations of fifteen separate water quality parameters including nutrients, major ions, sediment, and specific conductance were analyzed over the period 1982-2012 and a targeted trend analysis was performed from 1992-2012. Although environmental policy is geared toward addressing the long-standing problem of nutrient overenrichment, these efforts have had uneven success, with decreasing nutrient concentrations at urbanized sites and little to no change at agricultural sites. However, freshwaters are being salinized rapidly in all human-dominated land use types. Increasing salinity negatively affects biodiversity, mobilizes sediment-bound contaminants, and increases lead contamination of drinking water but the effects are poorly quantified. Therefore, while efforts to control nutrients are ongoing, rapid salinity increases are ushering in a new set of poorly-defined issues.
Environmental Science & Technology↗
Influences of herbivory and water on willow in elk winter range
Elimination of large predators and reduced hunter harvest have led to concerns that an increasing elk ( Cervus elaphus ) population may be adversely affecting vegetation on the low-elevation elk winter range of Rocky Mountain National Park, Colorado, USA. Beaver ( Castor canadensis ) and their impoundments also have declined dramatically (94%) in the same area over the past 50 years coincident with a 20% decline in willow ( Salix spp.) cover. From 1994 to 1998, we studied vegetation production responses of willow communities to elk herbivory and water availability. We estimated willow production by measuring current annual growth of shrubs in 9.3-m2 circular plots, and we measured herbaceous production by clipping vegetation within 0.25-m2 circular plots. Elk herbivory suppressed willow heights, leader lengths, annual production, and herbaceous productivity of willow communities. Water impoundment had a positive effect on herbaceous plant production, but little effect on shrubs, possibly because water tables were naturally high on the study sites even without beaver dams. Nevertheless, the winter range environment previously included more riparian willow habitat because of more stream area (47-69%) due to larger beaver populations. Elk herbivory appears to be the dominant force determining vegetation productivity in willow sites, but the effects may be exacerbated by lowered water tables. Fewer elk or protection from browsing, and water enhancement for <10 years along with management to encourage elk movement away from willow communities, could possibly work as strategies to reestablish sustainable willow communities.
Colorado↗
Lake-level variability and water availability in the Great Lakes
In this report, we present recorded and reconstructed (pre-historical) changes in water levels in the Great Lakes, relate them to climate changes of the past, and highlight major water-availability implications for storage, coastal ecosystems, and human activities. 'Water availability,' as conceptualized herein, includes a recognition that water must be available for human and natural uses, but the balancing of how much should be set aside for which use is not discussed. The Great Lakes Basin covers a large area of North America. The lakes capture and store great volumes of water that are critical in maintaining human activities and natural ecosystems. Water enters the lakes mostly in the form of precipitation and streamflow. Although flow through the connecting channels is a primary output from the lakes, evaporation is also a major output. Water levels in the lakes vary naturally on timescales that range from hours to millennia; storage of water in the lakes changes at the seasonal to millennial scales in response to lake-level changes. Short-term changes result from storm surges and seiches and do not affect storage. Seasonal changes are driven by differences in net basin supply during the year related to snowmelt, precipitation, and evaporation. Annual to millennial changes are driven by subtle to major climatic changes affecting both precipitation (and resulting streamflow) and evaporation. Rebounding of the Earth's surface in response to loss of the weight of melted glaciers has differentially affected water levels. Rebound rates have not been uniform across the basin, causing the hydrologic outlet of each lake to rise in elevation more rapidly than some parts of the coastlines. The result is a long-term change in lake level with respect to shoreline features that differs from site to site. The reconstructed water-level history of Lake Michigan-Huron over the past 4,700 years shows three major high phases from 2,300 to 3,300, 1,100 to 2,000, and 0 to 800 years ago. Within that record is a quasi-periodic rise and fall of about 160 ? 40 years in duration and a shorter fluctuation of 32 ? 6 years that is superimposed on the 160-year fluctuation. Recorded lake-level history from 1860 to the present falls within the longer-term pattern and appears to be a single 160-year quasi-periodic fluctuation. Independent investigations of past climate change in the basin over the long-term period of record confirm that most of these changes in lake level were responses to climatically driven changes in water balance, including lake-level highstands commonly associated with cooler climatic conditions and lows with warm climate periods. The mechanisms underlying these large hydroclimatic anomalies are not clear, but they may be related to internal dynamics of the ocean-atmosphere system or dynamical responses of the ocean-atmosphere system to variability in solar radiation or volcanic activity. The large capacities of the Great Lakes allow them to store great volumes of water. As calculated at chart datum, Lake Superior stores more water (2,900 mi3) than all the other lakes combined (2,539 mi3). Lake Michigan's storage is 1,180 mi3; Lake Huron's, 850 mi3; Lake Ontario's, 393 mi3; and Lake Erie's, 116 mi3. Seasonal lake-level changes alter storage by as much as 6 mi3 in Lake Superior and as little as 2.1 mi3 in Lake Erie. The extreme high and low lake levels measured in recorded lake-level history have altered storage by as much as 31 mi3 in Lake Michigan-Huron and as little as 9 mi3 in Lake Ontario. Diversions of water into and out of the lakes are very small compared to the total volume of water stored in the lakes. The water level of Lake Superior has been regulated since about 1914 and levels of Lake Ontario since about 1960. The range of Lake Superior water-level fluctuations and storage has not been altered greatly by regulation. However, fluctuations on Lake Ontario have been reduced from 6.6 ft preregulation
Circular↗
Hydrogeologic characteristics of the St. Croix River basin, Minnesota and Wisconsin: Implications for the susceptibility of ground water to potential contamination
Population growth in the St. Croix River Basin in Minnesota and Wisconsin has intensified concerns of county resource managers and the National Park Service, which is charged with protecting the St. Croix National Scenic Riverway, about the potential for ground-water contamination in the basin. This report describes a previously developed method that was adapted to illustrate potential ground-water-contamination susceptibility in the St. Croix River Basin. The report also gives an estimate of ground-water-residence time and surface-water/ground-water interaction as related to natural attenuation and movement of contaminants in five tributary basins. A ground-water-contamination-susceptibility map was adapted from a state-wide map of Wisconsin to the St. Croix River Basin by use of well-driller construction records and regional maps of aquifer properties in Minnesota and Wisconsin. Measures of various subsurface properties were combined to generate a spatial index of susceptibility. The subjective index method developed for the State of Wisconsin by Schmidt (1987) 1 was not derived from analyses of water-quality data or physical processes. Nonetheless, it was adapted for this report to furnish a seamless map across state boundaries that would be familiar to many resource managers. Following this method, areas most susceptible to contamination appear to have coarse-grained sediments (sands or gravels) and shallow water tables or are underlain by carbonate-bedrock aquifers. The least susceptible areas appear to have fine-grained sediments and deep water tables. If an aquifer becomes contaminated, the ground-water-residence time can affect potential natural attenuation along the ground-water-flow path. Mean basin ground-water-residence times were computed for the Apple, Kettle, Kinnickinnic, Snake and Sunrise River Basins, which are tributary basins to the St. Croix Basin, by use of average aquifer properties of saturated thickness, porosity, and recharge rates. The Apple River Basin had the shortest mean ground-water-residence times (20–120 years), owing largely to the moderate saturated thickness and high recharge rate in the basin. The Kinnickinnic and Sunrise River Basins had the longest mean residence times (60–350 and 70–390 years, respectively) chiefly because of the relatively large saturated thickness of the basins. Owing to limitations of the residence-time calculations, actual ground-water-residence times will vary around the mean values within each basin and may range from days or weeks in karst carbonate aquifers to millennia in deep confined sandstone aquifers. Areas of relatively short residence time (less than the median residence time in each basin) were identified by use of ground-water-flow models for each of the five tributary basins. Results of simulations show that these areas, in which contaminants may have relatively less time for natural attenuation along the short flow paths, generally occur near streams and rivers where ground water discharges to the surface. Finally, the ground-water-flow models were used to simulate ground-water/surface-water interaction in the five tributary basins. Results of simulations show that some lakes and reservoirs leak surface water into the ground-water-flow system on their downgradient side, where the surface-water outflow has been restricted by a dam or a naturally constricted outlet. These locations are noteworthy because contaminated surface waters could potentially enter the ground-water-flow system at these locations.
Minnesota, Wisconsin↗
Ground water in the Eugene-Springfield area, southern Willamette Valley, Oregon
The cities of Eugene and Springfield and their outlying suburban and rural districts constitute an area of rapid population growth where progressively greater volumes of ground water are being required for irrigation and industrial and public supplies. The area is also one of diverse geologic and hydrologic conditions. As used in this report, the Eugene-Springfield area covers about 450 square miles and includes a part of the lower foothills of the Coast and Cascade Ranges and a strip of the main valley plain of the southern Willamette Valley. Volcanic and sedimentary rock units exposed in the foothills range in age from Eocene to Miocene. In the main valley plain the older units are overlain by Pleistocene and Holocene alluvial deposits. Marine-deposited sandstone, siltstone, shale, and mudstone of the older sedimentary units are fine grained and poorly permeable and yield water slowly to wells. The volcanic rocks, primarily of dacitic and andesitic composition, yield small quantities of water that are generally adequate only for domestic use. The alluvial deposits (sand and gravel) of the valley plain (central lowland) contain the most productive aquifers in the area and are considered to be the only ground-water reservoir for which large-scale development of ground-water supplies is feasible. Aquifers in the area are recharged principally by direct infiltration of precipitation. Most of the precipitation, which averages about 4C inches per year, occurs during late autumn and winter. Minimum recharge by infiltration of precipitation to the alluvial aquifers beneath the valley plain is estimated to be about 100,000 acre-feet. Ground water is discharged naturally from the central lowland by seepage and spring flow to small streams, by subsurface outflow to adjacent areas, and by evapotranspiration. Storage capacity of the central lowland in the Eugene-Springfield area is estimated to be about 2.1 million acre-feet in the zone 10-150 feet below land surface. The quantity of ground water available annually from this area is far greater than the 23,000 acre-feet pumped for all uses in 1968. This pumpage was about 23 percent of the perennial yield (100,000 acre-ft), and about 77,000 acre-feet of water was left available for additional withdrawal. If annual withdrawals of water were increased to 100,000 acre-feet per year, the levels in the ground-water reservoir would be lowered. Once new equilibriums are established, increased withdrawals could be accommodated without progressive losses in aquifer storage or excessive losses in flow of the larger streams. Ground water from the alluvial deposits of the valley plain is chemically suitable for irrigation and other uses, as is most of the water obtained from perched-water bodies in the sedimentary and volcanic rocks. However, the mineral content of water from the older sedimentary rocks, particularly from deeper producing zones, is greater than the mineral content of water from the alluvial deposits. Locally, some of the water from the older rocks is too saline for most uses. Increased use of ground water may result in certain problems pertaining to waste-disposal practices, local overdraft of aquifers, well interference, and well construction. Present data are adequate to evaluate some of the factors relating to foreseeable problems but allow only tentative conclusions to be drawn about other factors, which include local direction of flow, rate of ground-water movement, and areas of possible ground-water contamination. Additional information obtained through systematic study will be needed to deal with these problems.
Oregon↗
A strategy for a stream-gaging network in Maryland
Water is a keystone resource. In abundance, it supplies cities, industries, and agriculture. To maintain healthy natural and human ecosystems, water must not only be present in adequate quantity, but it must be of suitable quality for its intended use. Water quality depends on the amount, or load, of contaminants, both natural and anthropogenic, that it contains. Accurate assessment of these contaminants requires that the amount of water flowing in a stream or river be known. To quantify streamflow in a given stream or river and the variation of that flow through time, it must be measured by use of stream gages. Monitoring water flow is fundamental to managing and protecting water resources, and requires a collaborative effort by all interested parties, including Federal, State, and local government agencies.
Maryl↗
Sediment properties and water movement through shallow unsaturated alluvium at an arid site for disposal of low-level radioactive waste near Beatty, Nye County, Nevada
A commercial disposal facility for low-level radioactive waste has been in operation near Beatty, Nevada, since 1962. The facility is in the arid Amargosa Desert where wastes are buried in trenches excavated into unsaturated alluvial sediments. Thick unsaturated zones in arid environments offer many potential advantages for disposal of radioactive wastes, but little is known about the natural movement of water near such facilities. Thus, a study was begun in 1982 to better define the direction and rates of water movement through the unsaturated zone in undisturbed sediments near the disposal facility. This report discusses the analyses of data collected between 1983 and 1988.
Nevada↗