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At least 667 records · Page 37Linked to original sources
USGS1994

Hydrogeologic and water-quality data for the main site, Naval Surface Warfare Center, Dahlgren Laboratory, Dahlgren, Virginia

Hydrogeologic and water-quality data were collected at the Naval Surface Warfare Center, Dahlgren Laboratory at Dahlgren, Virginia, as part of a hydrogeologic assessment of the shallow aquifer system begun in 1992. The U.S. Geological Survey conducted this study to provide the Navy with hydrogeologic data to meet the requirements of a Spill Contingency Plan. This report describes the ground-water observation-well network, hydro- geologic, and water-quality data collected between August 1992 and September 1993. The report includes a description of the locations and con- struction of 35 observation wells on the Main Site. Hydrologic data include lithologic core samples, geophysical logs, and vertical hydraulic conductivity measurements of selected core intervals. Hydrologic data include synoptic and hourly measurements of ground-water levels, observation-well slug tests to determine horizontal hydraulic conductivity, and tide data. Water-quality data include analyses of major dissolved constituents in ground water and surface water.

Open-File Report↗
USGS2025

Water-resources inventory and assessment at Katahdin Woods and Waters National Monument

The U.S. Geological Survey, in cooperation with the National Park Service, prepared a water-resources inventory and assessment for Katahdin Woods and Waters National Monument (KAWW). This compilation includes published and publicly accessible hydrologic data and resource assessments of streams, rivers, ponds, lakes, wetlands, vernal pools, and groundwater in and near KAWW. It also includes reports and datasets summarizing attributes of KAWW’s hydrologic infrastructure, such as stream crossings, dams, wastewater discharge plants, groundwater monitoring wells, and U.S. Geological Survey streamflow-gaging stations. Descriptions of data and details of current limitations in available datasets are included. Wetland, groundwater, streamflow, and water-quality information are all limited. Hydrography data are available; however, there are limited ground-truth data. Accurate streamlines within KAWW were developed from light detection and ranging (lidar) as a part of this work. Hydrologic infrastructure information is available from multiple sources; however, differences exist among the datasets. Datasets are summarized in appendix 1.

Maine↗
USGS2013

Groundwater hydrology and estimation of horizontal groundwater flux from the Rio Grande at selected locations in Albuquerque, New Mexico, 2003-9

The Albuquerque, New Mexico, area has two principal sources of water: groundwater from the Santa Fe Group aquifer system and surface water from the San Juan-Chama Diversion Project. From 1960 to 2002, groundwater withdrawals from the Santa Fe Group aquifer system have caused water levels to decline more than 120 feet in some places within the Albuquerque area, resulting in a great deal of interest in quantifying the river-aquifer interaction associated with the Rio Grande. In 2003, the U.S. Geological Survey in cooperation with the Bureau of Reclamation, the Middle Rio Grande Endangered Species Collaborative Program, and the U.S. Army Corps of Engineers began a detailed characterization of the hydrogeology of the Rio Grande riparian corridor in the Albuquerque, New Mexico, area to provide hydrologic data and enhance the understanding of rates of water leakage from the Rio Grande to the alluvial aquifer, groundwater flow through the aquifer, and discharge of water from the aquifer to the riverside drains. A simple conceptual model of flow indicates that the groundwater table gently slopes from the Rio Grande towards riverside drains and the outer boundaries of the inner valley. Water infiltrating from the Rio Grande initially moves vertically below the river, but, as flow spreads farther into the Rio Grande inner valley alluvial aquifer, flow becomes primarily horizontal. The slope of the water-table surface may be strongly controlled by the riverside drains and influenced by other more distal hydrologic boundary conditions, such as groundwater withdrawals by wells. Results from 35 slug tests performed in the Rio Grande inner valley alluvial aquifer during January and February 2009 indicate that hydraulic-conductivity values ranged from 5 feet per day to 160 feet per day with a median hydraulic-conductivity for all transects of 40 feet per day. Median annual horizontal hydraulic gradients in the Rio Grande inner valley alluvial aquifer ranged from 0.011 to 0.002. Groundwater fluxes through the alluvial aquifer calculated by using median slug-test results (qm slug ) and Darcy's law ranged from about 0.1 feet per day to about 0.7 feet per day. Groundwater fluxes calculated by using the Suzuki-Stallman method (qm heat ) ranged from 0.52 feet per day to 0.23 feet per day. Results from the Darcy's law and Suzuki-Stallman flux calculations were compared to discharge measured in riverside drains on both sides of the river north of the Montaño Bridge on February 26, 2009. Flow in the Corrales Riverside Drain increased by 1.4 cubic feet per second from mile 2 to mile 4, about 12 cubic feet per day per linear foot of drain. Flow in the Albuquerque Riverside Drain increased by 15 cubic feet per second between drain miles 0 and 3, about 82 cubic feet per day per linear foot of drain. The flux of water from the river to the aquifer was calculated to be 2.2 cubic feet per day per linear foot of river by using the median qm slug of 0.09 feet per day at Montaño transects west of the river. The total flux was calculated to be 6.0 cubic feet per day per linear foot of river by using the mean(qm heat of 0.24 feet per day for the Montaño transects west of the river. Assuming the Corrales Riverside Drain intercepted all of this flow, the qm slug or qm heat fluxes account for 18 to 50 percent, respectively, of the increase of flow in the drain. The flux of water from the river to the aquifer was calculated to be 15 cubic feet per day per linear foot of river by using the median qm slug of 0.30 feet per day at the Montaño transects east of the river. The flux of water from the river to the aquifer was calculated to be 17 cubic feet per day per linear foot of river by using the mean flux calculated from the Suzuki-Stallman method for the Montaño East transects of 0.34 feet per day. Assuming the Albuquerque Riverside Drain intercepted all this flow, the qm slug or (qm heat fluxes would only account for 18 to 21 percent, respectively, of the increase in flow in the drain. The comparison of these results with those of previous investigations suggests that calculated flux through the Rio Grande inner valley alluvial aquifer is strongly scale dependent and that the thickness of aquifer through which river water flows may be greater than indicated by the vertical temperature profiles.

Albuquerque, New Mexico↗
USGS2014

Preliminary geochemical assessment of water in selected streams, springs, and caves in the Upper Baker and Snake Creek drainages in Great Basin National Park, Nevada, 2009

Water in caves, discharging from springs, and flowing in streams in the upper Baker and Snake Creek drainages are important natural resources in Great Basin National Park, Nevada. Water and rock samples were collected from 15 sites during February 2009 as part of a series of investigations evaluating the potential for water resource depletion in the park resulting from the current and proposed groundwater withdrawals. This report summarizes general geochemical characteristics of water samples collected from the upper Baker and Snake Creek drainages for eventual use in evaluating possible hydrologic connections between the streams and selected caves and springs discharging in limestone terrain within each watershed. Generally, water discharging from selected springs in the upper Baker and Snake Creek watersheds is relatively young and, in some cases, has similar chemical characteristics to water collected from associated streams. In the upper Baker Creek drainage, geochemical data suggest possible hydrologic connections between Baker Creek and selected springs and caves along it. The analytical results for water samples collected from Wheelers Deep and Model Caves show characteristics similar to those from Baker Creek, suggesting a hydrologic connection between the creek and caves, a finding previously documented by other researchers. Generally, geochemical evidence does not support a connection between water flowing in Pole Canyon Creek to that in Model Cave, at least not to any appreciable extent. The water sample collected from Rosethorn Spring had relatively high concentrations of many of the constituents sampled as part of this study. This finding was expected as the water from the spring travelled through alluvium prior to being discharged at the surface and, as a result, was provided the opportunity to interact with soil minerals with which it came into contact. Isotopic evidence does not preclude a connection between Baker Creek and the water discharging from Rosethorn Spring. The residence time of water discharging into the caves and from selected springs sampled as part of this study ranged from 10 to 25 years. Within the upper Snake Creek drainage, the results of this study show geochemical similarities between Snake Creek and Outhouse Spring, Spring Creek Spring, and Squirrel Spring Cave. The strontium isotope ratio ( 87 Sr/ 86 Sr) for intrusive rock samples representative of the Snake Creek drainage were similar to carbonate rock samples. The water sample collected from Snake Creek at the pipeline discharge point had lower strontium concentrations than the sample downstream and a similar 87 Sr/ 86 Sr value as the carbonate and intrusive rocks. The chemistry of the water sample was considered representative of upstream conditions in Snake Creek and indicates minimal influence of rock dissolution. The results of this study suggest that water discharging from Outlet Spring is not hydrologically connected to Snake Creek but rather is recharged at high altitude(s) within the Snake Creek drainage. These findings for Outlet Spring largely stem from the relatively high specific conductance and chloride concentration, the lightest deuterium (δD) and oxygen-18 (δ 18 O) values, and the longest calculated residence time (60 to 90 years) relative to any other sample collected as part of this study. With the exception of water sampled from Outlet Spring, the residence time of water discharging into Squirrel Spring Cave and selected springs in the upper Snake Creek drainage was less than 30 years.

Nevada↗
USGS2015

Summary of hydrologic conditions in Kansas, water year 2014

The U.S. Geological Survey Kansas Water Science Center, in cooperation with Federal, State, and local agencies, maintains a long-term network of hydrologic monitoring gages in the State of Kansas. These include 206 real-time streamgages, 12 real-time reservoir-level monitoring stations, and 32 groundwater monitoring wells. These data and associated analyses, accumulated over time, provide a unique overview of hydrologic conditions and help improve our understanding of Kansas’s water resources. Yearly hydrologic conditions are determined by comparing statistical analyses of current and historical water year data for the period of record. These data are used in protecting life and property, and managing water resources for agricultural, industrial, public supply, ecological, and recreational purposes.

Kansas↗
USGS2012

Science to support the understanding of south Texas surface-water and groundwater resources in a changing landscape

Against a backdrop of constant cycles of extreme hydrologic conditions ranging from oppressive droughts to life-threatening floods, the water-resource landscape of south Texas is undergoing constant change. Demands on water resources are increasing because of changes related to population growth, energy demands, agricultural practices, and other human-related activities. In south Texas, the Nueces, San Antonio, and Guadalupe River Basins cover approximately 50,000 square miles and include all or part of 45 counties. These stream systems transect the faulted and fractured carbonate rocks of the Edwards aquifer recharge zone and provide the largest sources of recharge to the aquifer. As the streams make their way to the Gulf of Mexico, they provide water for communities and ecosystems in south Texas and deliver water, sediment, and nutrients to the south Texas bays and estuaries. The U.S. Geological Survey (USGS) works in cooperation with other local, State, and Federal agencies to provide timely access to water data, publications, and information to foster a better understanding of the water resources of south Texas. The USGS and our cooperators are involved in a wide variety of programs for collecting hydrologic data and scientific information in the changing landscape of south Texas to help our cooperators effectively address water-resource issues in this part of the State. This fact sheet provides an overview of our collaborative scientific endeavors in the basins of the Nueces, San Antonio, and Guadalupe Rivers and lower Rio Grande. An overview of USGS capabilities pertaining to water resource issues in Texas, including recently completed and ongoing studies in south Texas, is available at http://tx.usgs.gov/Capabilities/index.html.

Texas↗
USGS2015

Assessment of aquifer properties, evapotranspiration, and the effects of ditching in the Stoney Brook watershed, Fond du Lac Reservation, Minnesota, 2006-9

The U.S. Geological Survey, in cooperation with the Fond du Lac Band of Lake Superior Chippewa, assessed hydraulic properties of geologic material, recharge, and evapotranspiration, and the effects of ditching on the groundwater resources in the Stoney Brook watershed in the Fond du Lac Reservation. Geologic, groundwater, and surface-water data were collected during 2006–9 to estimate hydrologic properties in the watershed. Streamflow and groundwater levels in the shallow glacial deposits in the Stoney Brook watershed were analyzed to estimate groundwater-flow directions, groundwater recharge, and evapotranspiration within the watershed and to assess the effect of ditches on surrounding groundwater resources. Groundwater, streamflow, and precipitation data collected during the study (2006–9) can be used to update the U.S. Department of Agriculture’s Natural Resource Conservation Service and Fond du Lac Resource Management Division surface-water models, which are used to evaluate the effect of proposed adjustments to the ditching system on streamflow on wild rice production and aquatic habitats. Specific yields calculated from the well water levels ranged from 0.11 to 0.40, and hydraulic conductivities determined from water levels measured during well slug tests ranged from 1 to 7 feet per day. The values for specific yields were similar to values obtained in other studies done in glacial materials of similar composition in Minnesota. The higher hydraulic conductivity estimate (7 feet per day) was similar to lower hydraulic conductivities estimated in another hydrologic study conducted in Carlton County, Minnesota. The installation of drainage ditches in the Stoney Brook watershed has reduced water levels in lakes connected to the ditch system, and has locally reduced groundwater levels in shallow groundwater adjacent to the ditches and lakes. Differences in near-ditch groundwater hydrographs relative to far-ditch groundwater hydrographs indicate that the effect of the ditches on groundwater is only localized to near-ditch areas. These hydrograph differences resulted in large differences between recharge estimated at wells near and far from ditches. In this study, recharge estimated at wells within 50 feet of a ditch was influenced by ditch-water levels. Annual groundwater recharge estimates from water levels and streamflows during 2006–9 ranged from 0.36 to 34.8 inches, and varied with climate, geology, and well location relative to ditches. The higher recharge estimates were determined from analysis of groundwater levels in wells near the ditches because the shallow groundwater in these wells received both infiltration from ditches and areal groundwater recharge from precipitation. The water-table fluctuation method using a manual groundwater recession approach for wells far from ditches provided the best estimates of areal groundwater recharge to the shallow glacial aquifer because water levels in these wells were not affected by water infiltrating from ditches (bank storage). For wells more than 400 feet from ditches, mean annual areal groundwater recharge estimates using the manual groundwater recession approach for wells screened mostly in outwash sands during 2007, 2008, and 2009 ranged from 4.47 to 18.6 inches (wells 5, 7, 13, 14 and 15), and ranged from 0.43 to 2.85 inches for wells screened mostly in clayey sand or sandy clay (wells 9 and 16). Recharge estimates at wells far from ditches were similar to basinwide recharge estimates from streamflow. Daily fluctuations in water levels in two wells indicated that the evapotranspiration extinction depth in the Stoney Brook watershed is approximately 4.6 to 6 feet below the land surface. A polynomial regression fit of the daily evapotranspiration rates during 2006–9 for well 1 produced a total evapotranspiration estimate of 16.1 inches from June 26 to October 6 for every year. Evapotranspiration estimated from daily water-level fluctuations in wells near ditches is relatively high. The ditch-water surface allowed for relatively high evaporation compared to the land surface, which, with a good hydraulic connection to surrounding groundwater, resulted in relatively high fluctuations in daily groundwater levels near ditches, resulting in high evapotranspiration estimates.

Minnesota↗
USGS2026

Salinas Valley integrated hydrologic and reservoir operations models, Monterey and San Luis Obispo Counties, California

The area surrounding the Salinas Valley groundwater basin in Monterey and San Luis Obispo Counties of California is a highly productive agricultural area, contributes substantially to the local economy, and provides a substantial portion of vegetables and other agricultural commodities to the Nation. This region of California provides about half of the Nation’s lettuce, celery, broccoli, and spinach each year. Thus, this agricultural area provides substantial volumes of agricultural products not just for California but for the United States. Changes in population and increased agricultural development, which includes a shift toward more water-intensive crops, and climate variability, have put increasing demand on both surface-water and groundwater resources in the valley. This situation has resulted in water management challenges in the Salinas Valley that generally relate to the distribution of the water supply throughout the basin. Where and when the water is present in the surface and subsurface does not coincide with where and when the water is needed. Historically, to deal with the distribution issue, water has been used conjunctively in the valley. Conjunctive use is a water management strategy that coordinates surface-water and groundwater use to maximize water availability. Groundwater is used throughout the Salinas Valley to meet water demands when surface-water supplies are insufficient. The availability of surface water is constrained by climate. Precipitation and streamflow vary seasonally and year to year. Although there are two reservoirs in the Salinas Valley to capture and store water during wet periods, the only conveyance of reservoir water to coastal agricultural areas is the Salinas River. Increasing demand for groundwater and surface-water resources throughout the Salinas Valley has resulted in undesirable effects from unsustainable water use, such as surface-water depletion, groundwater-level declines, storage depletion in the principal aquifers, and seawater intrusion. To address these escalating issues, local communities, water management agencies, and groundwater sustainability agencies are evaluating how to sustainably manage both their surface-water and groundwater resources. To meet water demands and reduce the undesirable effects of unsustainable water use, continued conjunctive management of surface water and groundwater would ideally incorporate strategies to deal with increases in demand and climate variability. To evaluate the challenging water management issues in the Salinas Valley, the U.S. Geological Survey, Monterey County Water Resources Agency, and the Salinas Valley Basin Groundwater Sustainability Agency developed a comprehensive suite of models that represent the Salinas Valley hydrogeologic system called the Salinas Valley System Model. The geologic framework is known as the Salinas Valley Geologic Framework and was developed to characterize the subsurface using various topographic and geologic data sources, including information on hydrogeologic units, their surfaces and extents, geologic structures, lithology, and elevations from borehole data and cross sections, as well as details on faults and existing models. The surface-water model is called the Salinas Valley Watershed Model and simulates the Salinas River watershed. Monthly surface-water inflows into the integrated hydrologic model domain were simulated using the Salinas Valley Watershed Model. The historical model uses historical climate data, water and land use data, and reservoir releases to simulate agricultural operations, including landscape water demands, diversions, and reclaimed wastewater. The operational model adds an embedded reservoir operations framework to the simulation of the historical model that allows specified operational rules to simulate reservoir releases and changes in reservoir storage. The operational model assumes current reservoir operations and constant land use, which differs from historical conditions. Thus, the operational model is a hypothetical baseline model that can be used by local water managers to evaluate and quantify potential benefits of water supply projects. Together, the geologic framework, watershed, historical, and operational models form a tool that can be used to simulate irrigated agriculture and associated reservoir operations of the integrated hydrologic system of the Salinas Valley.

California↗
USGS1997

Use of isotopic data to evaluate recharge and geologic controls on the movement of ground water in Las Posas Valley, Ventura County, California

Injection, storage, and recovery of imported water is planned for aquifers underlying Las Posas Valley. To evaluate sources of ground-water recharge and the age of the water (time since recharge), and to identify barriers to ground-water flow prior to the injection of imported water, samples from wells and surface sources were collected and analyzed for chemical and isotopic composition. The delta oxygen- 18 and delta deuterium composition in almost 50 samples from 32 wells ranged from -6.0 to -7.9 per mil, and -40 to -60 per mil, respectively; and in 13 samples of surface water at 6 sites the composition ranged from -6.2 to -9.4 per mil, and -42 to -71 per mil, respectively. Water from wells in the upper aquifer system near Arroyo Simi and Arroyo Las Posas (different reaches of the same stream) was isotopi cally lighter than water from other wells sampled and was similar in isotopic composition to water in the stream. Water in the stream is a mixture of local water and imported water from northern California that was discharged to the stream as treated municipal wastewater. Water from wells near the stream contained tritium and, therefore, was recharged less than 50 years ago. Water from wells in other parts of the valley was isotopically heavier, did not contain tritium, and, therefore, was recharged more than 50 years ago. Interpreted carbon-14 ages for water from wells along a flow path through the valley ranged from at least 800 to more than 8,000 years before present. There were large differences in the chemistry, isotopic composition, and interpreted age of water from wells between the eastern and western parts of Las Posas Valley. These changes are consistent with geologic and hydrologic data that suggest the presence of a barrier to ground-water flow between east and west Las Posas Valley.

Water-Resources Investigations Report↗
USGS2007

Effects of the temporal variability of evapotranspiration on hydrologic simulation in central Florida

The transient response of a hydrologic system can be of concern to water-resource managers, because it is often extreme relatively short-lived events, such as floods or droughts, that profoundly influence the management of the resource. The water available to a hydrologic system for stream flow and aquifer recharge is determined by the difference of precipitation and evapotranspiration (ET). As such, temporal variations in precipitation and ET determine the degree of influence each has on the transient response of the hydrologic system. Meteorological, ET, and hydrologic data collected from 1993 to 2003 and spanning 1- to 3 2/3 -year periods were used to develop a hydrologic model for each of five sites in central Florida. The sensitivities of simulated water levels and flows to simple approximations of ET were quantified and the adequacy of each ET approximation was assessed. ET was approximated by computing potential ET, using the Hargreaves and Priestley-Taylor equations, and applying vegetation coefficients to adjust the potential ET values to actual ET. The Hargreaves and Priestley-Taylor ET approximations were used in the calibrated hydrologic models while leaving all other model characteristics and parameter values unchanged. Two primary factors that influence how the temporal variability of ET affects hydrologic simulation in central Florida were identified: (1) stochastic character of precipitation and ET and (2) the ability of the local hydrologic system to attenuate variability in input stresses. Differences in the stochastic character of precipitation and ET, both the central location and spread of the data, result in substantial influence of precipitation on the quantity and timing of water available to the hydrologic system and a relatively small influence of ET. The temporal variability of ET was considerably less than that of precipitation at each site over a wide range of time scales (from daily to annual). However, when precipitation and ET are of similar magnitude, small errors in ET can produce relatively large errors in available water, and accurate estimates of actual ET are more important. Local hydrologic conditions can also be an important factor influencing the hydrologic response to ET variability. Various points along a flow path in a hydrologic system respond differently to temporal variations in ET. For example, soil moisture contents in the root zone are sensitive to daily variations in ET, whereas spring flow responds to only longer term variations in ET. Both the Hargreaves and Priestley-Taylor equations for potential ET, when applied with an annually invariant monthly vegetation coefficient derived from comparison of measured ET with computed potential ET values, can be used with a hydrologic model to produce reasonable predictions of water levels and flows. Baseline-adjusted modified coefficients of efficiency for simulated water levels ranged from 0.0, indicating that water levels were simulated equally as well with approximated ET as with actual ET values, to -0.6, indicating that water levels were simulated better with actual ET values. Simulations using the Hargreaves approximation consistently yielded larger absolute and relative errors than the Priestley-Taylor approximation. However, the differences between the Hargreaves and Priestley-Taylor simulations generally were much smaller than differences between these simulations and the simulations using actual ET. This suggests that the simpler Hargreaves equation may be an adequate substitute for the more complex Priestley-Taylor equation, depending on the level of accuracy required to satisfy the particular modeling objectives.

Florida↗
USGS2000

Water-quality assessment of part of the Upper Mississippi River Basin, Minnesota and Wisconsin - Ground-water quality in an agricultural area of Sherburne County, Minnesota, 1998

The quality of shallow ground water in a 75-mi 2 agricultural area of the Anoka Sand Plain aquifer in central Minnesota is described as part of the National Water Quality Assessment (NAWQA) Program - a national-scale assessment of the quality of water resources within large study units in various hydrologic settings. Data were collected during 1998 from 29 wells completed in the aquifer, which predominantly consists of surficial glacial sand and gravel sediments. The depth below land surface to the water table ranged from 3.3 to 44 ft (median of 15.5 ft). Ground water was of the calciummagnesium bicarbonate type. Ionic constituents also included sodium, sulfate, and chloride. Iron and manganese concentrations generally were not greater than their U.S. Environmental Protection Agency (USEPA) Secondary Maximum Contaminant Levels (300 and 50 ug/L, respectively). About 38 percent of 29 samples had nitrate-N (nitrogen) concentrations greater than the USEPA Maximum Contaminant Level (MCL) of 10 mg/L. About 72 percent of the samples had nitrate-N concentrations greater than the presumed natural background level of 3 mg/L. The maximum nitrate-N concentration was 47 mg/L. The median nitrate-N concentration of 7.1 mg/L, although not greater than the MCL, exceeded the natural background level. Nitrogen isotope ratios indicate that the sources of nitrate were commercial fertilizer and soil organic matter. Concentrations of total dissolved phosphorus and orthophosphate were generally less than 1 mg/L. About 86 percent of 29 samples had detectable concentrations of at least 1 of 13 pesticide compounds. The samples were analyzed for 83 pesticide compounds. Frequencies of detection of these compounds were: deethylatrazine-79 percent; atrazine-76 percent; metolachlor-41 percent; metribuzin and bentazon-21 percent; prometon-10 percent; tebuthiuron-7 percent; and alachlor, 2,6-diethylaniline, dicamba, dinoseb, malathion, and simazine-3 percent. The detected pesticide compounds had concentrations less than 1 ug/L. Detected compounds with USEPA MCLs (atrazine, bentazon, alachlor, dinoseb, and simazine) had concentrations less than their respective MCLs. About 50 percent of 20 samples analyzed for 86 volatile organic compounds (VOCs) had detectable concentrations of at least 1 of 7 VOCs. Frequencies of detection of these 7 VOCs were: 1,2,3,4-tetramethylbenzene-40 percent; and trichlorofluoromethane, styrene, chloromethane, benzene, methylbenzene, and trichloromethane-5 percent. The detected VOCs had concentrations less than 0.120 ug/L. Detected VOCs with USEPA MCLs - styrene, benzene, methylbenzene, and trichloromethane - were present at concentrations 2-4 orders of magnitude less than their respective MCLs. Tritium concentrations had a range of from 7.5 to 18.8 tritium units (TUs) and a median of 12.5 TUs. These concentrations indicate that the ground water predominantly recharged after testing of thermonuclear weapons during the early 1950's.

Minnesota↗
USGS2004

The USGS/EROS Data Center produces seamless hydrologic derivatives with GIS

Increasingly, many local, state, and federal agencies mandated to manage water resources are finding that their needs are not being met by existing digital data sets. Current national coverage of digital data sets, such as drainage basin boundaries and consistent elevation-derived parameters, does not exist or is not of a suitable scale or consistency to allow management of small or midsize watersheds. This problem has become more significant as the management of water resources, both in terms of quantity and quality, is becoming more and more based on the watershed scale.

ArcNews↗
USGS2016

Science center capabilities to monitor and investigate Michigan’s water resources, 2016

Michigan faces many challenges related to water resources, including flooding, drought, water-quality degradation and impairment, varying water availability, watershed-management issues, stormwater management, aquatic-ecosystem impairment, and invasive species. Michigan’s water resources include approximately 36,000 miles of streams, over 11,000 inland lakes, 3,000 miles of shoreline along the Great Lakes (MDEQ, 2016), and groundwater aquifers throughout the State. The U.S. Geological Survey (USGS) works in cooperation with local, State, and other Federal agencies, as well as tribes and universities, to provide scientific information used to manage the water resources of Michigan. To effectively assess water resources, the USGS uses standardized methods to operate streamgages, water-quality stations, and groundwater stations. The USGS also monitors water quality in lakes and reservoirs, makes periodic measurements along rivers and streams, and maintains all monitoring data in a national, quality-assured, hydrologic database. The USGS in Michigan investigates the occurrence, distribution, quantity, movement, and chemical and biological quality of surface water and groundwater statewide. Water-resource monitoring and scientific investigations are conducted statewide by USGS hydrologists, hydrologic technicians, biologists, and microbiologists who have expertise in data collection as well as various scientific specialties. A support staff consisting of computer-operations and administrative personnel provides the USGS the functionality to move science forward. Funding for USGS activities in Michigan comes from local and State agencies, other Federal agencies, direct Federal appropriations, and through the USGS Cooperative Matching Funds, which allows the USGS to partially match funding provided by local and State partners. This fact sheet provides an overview of the USGS current (2016) capabilities to monitor and study Michigan’s vast water resources. More information regarding projects by the Michigan Water Science Center (MI WSC) is available at http://mi.water.usgs.gov/ .

Michigan↗
USGS2008

Precipitation, Ground-water Hydrology, and Recharge Along the Eastern Slopes of the Sandia Mountains, Bernalillo County, New Mexico

The spatial and temporal distribution of recharge to carbonate and clastic aquifers along the eastern slopes of the Sandia Mountains was investigated by using precipitation, water-level, dissolved chloride, and specific-conductance data. The U.S. Geological Survey (USGS), in cooperation with the Bernalillo County Public Works Division, conducted a study to assess ground-water conditions and provide technical data that could be used as a basis for management and future planning of eastern Bernalillo County water resources. The intent of the investigation was to improve the current understanding of subsurface mechanisms controlling recharge dynamics in a geologically complex aquifer system. In the Sandia Mountains, precipitation events are generally limited to snowfalls in winter months and monsoon rainfall in late summer. Monthly meteorological data from weather stations in the study area indicate that monsoon rainfall during July and August constitutes close to one-third of annual precipitation totals. Following precipitation and snowmelt events, daily ground-water level data show low-amplitude, long-duration peaks in hydrographs of wells north and west of the Tijeras Fault. Hydrographs of monthly and biannual water-level data from across the study area show seasonal variation and water-level fluctuations in excess of 30 ft during a period of below-average precipitation. Water level observations in 67 percent of wells showing drought-induced water-level declines rebounded to at or near predrought conditions within 6 months of return to normal climate conditions. Cross-correlation of annual hydrologic data shows aquifer response to periods of monsoon recharge to persist from 1 to 6 months following events. The lag time between precipitation input and response of water levels or solute concentrations was largest near the Tijeras and Gutierrez Faults. These results indicate regional faults hydrologically isolate the Tijeras Graben from groundwater recharge originating at high elevations along the eastern slopes of the Sandia Mountains. Recharge rates calculated by using the chloride-mass-balance method for five springs located at the base of the Sandia Mountains ranged from 1 to 23 percent of annual precipitation.

Scientific Investigations Report↗
USGS2016

POLARIS: A 30-meter probabilistic soil series map of the contiguous United States

A new complete map of soil series probabilities has been produced for the contiguous United States at a 30 m spatial resolution. This innovative database, named POLARIS, is constructed using available high-resolution geospatial environmental data and a state-of-the-art machine learning algorithm (DSMART-HPC) to remap the Soil Survey Geographic (SSURGO) database. This 9 billion grid cell database is possible using available high performance computing resources. POLARIS provides a spatially continuous, internally consistent, quantitative prediction of soil series. It offers potential solutions to the primary weaknesses in SSURGO: 1) unmapped areas are gap-filled using survey data from the surrounding regions, 2) the artificial discontinuities at political boundaries are removed, and 3) the use of high resolution environmental covariate data leads to a spatial disaggregation of the coarse polygons. The geospatial environmental covariates that have the largest role in assembling POLARIS over the contiguous United States (CONUS) are fine-scale (30 m) elevation data and coarse-scale (~ 2 km) estimates of the geographic distribution of uranium, thorium, and potassium. A preliminary validation of POLARIS using the NRCS National Soil Information System (NASIS) database shows variable performance over CONUS. In general, the best performance is obtained at grid cells where DSMART-HPC is most able to reduce the chance of misclassification. The important role of environmental covariates in limiting prediction uncertainty suggests including additional covariates is pivotal to improving POLARIS' accuracy. This database has the potential to improve the modeling of biogeochemical, water, and energy cycles in environmental models; enhance availability of data for precision agriculture; and assist hydrologic monitoring and forecasting to ensure food and water security.

Geoderma↗
USGS2009

Identifying baldcypress-water tupelo regeneration classes in forested wetlands of the Atchafalaya Basin, Louisiana

Baldcypress-water tupelo (cypress-tupelo) swamps are critically important coastal forested wetlands found throughout the southeastern U.S. The long-term survival and sustainability of these swamp forests is unknown due to large-scale changes in hydrologic regimes that prevent natural regeneration following logging or mortality. We used NWI wetland maps and remotely sensed hydrologic data to map cypress-tupelo communities, surface water, and the extent and location of proposed regeneration condition classes for cypress-tupelo swamps in the Atchafalaya Basin, LA. Only 6,175 ha (5.8%) of the 106,227 ha of cypress-tupelo forest in the Lower Atchafalaya Basin Floodway was classified as capable of naturally regenerating. Over 23% (24,525 ha) of the forest area was mapped as unable to regenerate either naturally or artificially. The loss and conversion of nearly 25,000 ha of cypress-tupelo forest would have significant and long-lasting impacts on ecosystem services such as wildlife habitat for birds and Louisiana black bears. Given the landscape-scale changes in surface elevations and flooding depths and durations throughout southern Louisiana, similar conditions and impacts are likely applicable to all coastal cypress-tupelo forests in Louisiana. Better data on flooding during the growing season are needed to more accurately identify and refine the location and spatial extent of the regeneration condition classes.

Louisiana↗
USGS2019

Monitoring the Riverine Pulse: Applying high-frequency nitrate data to advance integrative understanding of biogeochemical and hydrological processes

Widespread deployment of sensors that measure river nitrate (NO3-) concentrations has led to many recent publications in water resources journals including review papers focused on data quality assurance, improved load calculations, and better nutrient management. The principal objective of this paper is to review and synthesize studies of high-frequency NO3- data that have aimed to improve understanding of the hydrologic and biogeochemical processes underlying episodic, diel, and long-term stream NO3- dynamics. Investigations have provided unprecedented detail on hysteresis and flushing patterns during high flow, seasonal variation during baseflow, and responses to multi-year climate variation. Analyses of high-frequency data have led to notable advances in understanding how climate variation affects spatial and temporal NO3- patterns, especially dry-wet cycles and antecedent moisture. Further advances have been limited by few investigations that include high-frequency measurements outside the channel and the short duration of many records. High-frequency data for multiple constituents have provided new insight to the relative roles of hydrology and biogeochemistry as highlighted by studies of the roles of autotrophic uptake, denitrification, riparian evapotranspiration, and temperature-driven changes in viscosity as drivers of diel patterns. Comparisons of short-duration high-frequency data with long-duration low frequency data have described similarities and differences in concentration – discharge patterns and highlighted the role of legacy stores. Investigators have applied innovative analysis approaches not previously possible with low-frequency or temporally-irregular data. Future availability of long-duration high-frequency data will provide new insight to processes, resulting in improved conceptual models and a deeper understanding of the role of climate variation.

WIREs Water↗