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At least 163 records · Page 9Linked to original sources
USGS2017

Hydrogeology and simulated groundwater flow and availability in the North Fork Red River aquifer, southwest Oklahoma, 1980–2013

On September 8, 1981, the Oklahoma Water Resources Board established regulatory limits on the maximum annual yield of groundwater (343,042 acre-feet per year) and equal-proportionate-share (EPS) pumping rate (1.0 acre-foot per acre per year) for the North Fork Red River aquifer. The maximum annual yield and EPS were based on a hydrologic investigation that used a numerical groundwater-flow model to evaluate the effects of potential groundwater withdrawals on groundwater availability in the North Fork Red River aquifer. The Oklahoma Water Resources Board is statutorily required (every 20 years) to update the hydrologic investigation on which the maximum annual yield and EPS were based. Because 20 years have elapsed since the final order was issued, the U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted an updated hydrologic investigation and evaluated the effects of potential groundwater withdrawals on groundwater flow and availability in the North Fork Red River aquifer in Oklahoma. This report describes a hydrologic investigation of the North Fork Red River aquifer that includes an updated summary of the aquifer hydrogeology. As part of this investigation, groundwater flow and availability were simulated by using a numerical groundwater-flow model. The North Fork Red River aquifer in Beckham, Greer, Jackson, Kiowa, and Roger Mills Counties in Oklahoma is composed of about 777 square miles (497,582 acres) of alluvium and terrace deposits along the North Fork Red River and tributaries, including Sweetwater Creek, Elk Creek, Otter Creek, and Elm Fork Red River. The North Fork Red River is the primary source of surface-water inflow to Lake Altus, which overlies the North Fork Red River aquifer. Lake Altus is a U.S. Bureau of Reclamation reservoir with the primary purpose of supplying irrigation water to the Lugert-Altus Irrigation District. A hydrogeologic framework was developed for the North Fork Red River aquifer and included a definition of the aquifer extent and potentiometric surface, as well as a description of the textural and hydraulic properties of aquifer materials. The hydrogeologic framework was used in the construction of a numerical groundwater-flow model of the North Fork Red River aquifer described in this report. A conceptual model of aquifer inflows and outflows was developed for the North Fork Red River aquifer to constrain the construction and calibration of a numerical groundwater-flow model that reasonably represented the groundwater-flow system. The conceptual-model water budget estimated mean annual inflows to and outflows from the North Fork Red River aquifer for the period 1980–2013 and included a sub-accounting of mean annual inflows and outflows for the portions of the aquifer that were upgradient and downgradient from Lake Altus. The numerical groundwater-flow model simulated the period 1980–2013 and was calibrated to water-table-altitude observations at selected wells, monthly base flow at selected streamgages, net streambed seepage as estimated for the conceptual model, and Lake Altus stage. Groundwater-availability scenarios were performed by using the calibrated numerical groundwater-flow model to (1) estimate the EPS pumping rate that guarantees a minimum 20-, 40-, and 50-year life of the aquifer, (2) quantify the potential effects of projected well withdrawals on groundwater storage over a 50-year period, and (3) simulate the potential effects of a hypothetical (10-year) drought on base flow and groundwater storage. The results of the groundwater-availability scenarios could be used by the Oklahoma Water Resources Board to reevaluate the maximum annual yield of groundwater from the North Fork Red River aquifer. EPS scenarios for the North Fork Red River aquifer were run for periods of 20, 40, and 50 years. The 20-, 40-, and 50-year EPS pumping rates under normal recharge conditions were 0.59, 0.52, and 0.52 acre-foot per acre per year, respectively. Given the 497,582-acre aquifer area, these rates correspond to annual yields of about 294,000, 259,000, and 259,000 acre-feet per year, respectively. Groundwater storage at the end of the 20-year EPS scenario was about 951,000 acre-feet, or about 1,317,000 acre-feet (58 percent) less than the starting EPS scenario storage. This decrease in storage was equivalent to a mean water-level decline of about 22 feet. Most areas of the active alluvium near the North Fork Red River, Elk Creek, and Elm Fork Red River remained partially saturated through the end of the EPS scenario because of streambed seepage. Lake Altus storage was reduced to zero after 6–7 years of EPS pumping in each scenario. Projected 50-year pumping scenarios were used to simulate the effects of selected well withdrawal rates on groundwater storage of the North Fork Red River aquifer and base flows in the North Fork Red River upstream from Lake Altus. The effects of well withdrawals were evaluated by comparing changes in groundwater storage and base flow between four 50-year scenarios using (1) no groundwater pumping, (2) mean pumping rates for the study period (1980–2013), (3) 2013 pumping rates, and (4) increasing demand pumping rates. The increasing demand pumping rates assumed a 20.4-percent increase in pumping over 50 years based on 2010–60 demand projections for southwest Oklahoma. Groundwater storage after 50 years with no pumping was about 2,606,000 acre-feet, or 137,000 acre-feet (5.5 percent) greater than the initial groundwater storage; this groundwater storage increase is equivalent to a mean water-level increase of 2.3 feet. Groundwater storage after 50 years with the mean pumping rate for the study period (1980–2013) was about 2,476,000 acre-feet, or about 7,000 acre-feet (0.3 percent) greater than the initial groundwater storage; this groundwater storage increase is equivalent to a mean water-level increase of 0.1 foot. Groundwater storage at the end of the 50-year period with 2013 pumping rates was about 2,398,000 acre-feet, or about 70,000 acre-feet (2.8 percent) less than the initial storage; this groundwater storage decrease is equivalent to a mean water-level decline of 1.2 feet. Groundwater storage at the end of the 50-year period with increasing demand pumping rates was about 2,361,000 acre-feet, or about 107,000 acre-feet (4.3 percent) less than the initial storage; this groundwater storage decrease is equivalent to a mean water-level decline of 1.8 feet. Mean annual base flow simulated at the Carter streamgage (07301500) on North Fork Red River increased by about 4,000 acre-feet (10 percent) after 50 years with no pumping and decreased by about 5,400 acre-feet (13 percent) after 50 years with increasing demand pumping rates. Mean annual base flow simulated at the North Fork Red River inflow to Lake Altus increased by about 7,400 acre-feet (15 percent) after 50 years with no pumping and decreased by about 5,800 acre-feet (12 percent) after 50 years with increasing demand pumping rates. A hypothetical 10-year drought scenario was used to simulate the effects of a prolonged period of reduced recharge on groundwater storage and Lake Altus stage and storage. Drought effects were quantified by comparing the results of the drought scenario to those of the calibrated numerical model (no drought). To simulate the hypothetical drought, recharge in the calibrated numerical model was reduced by 50 percent during the simulated drought period (1984–1993). Groundwater storage at the end of the drought period was about 2,271,000 acre-feet, or about 426,000 acre-feet (15.8 percent) less than the groundwater storage of the calibrated numerical model. This decrease in groundwater storage is equivalent to a mean water-table-altitude decline of 7.1 feet. At the end of the 10-year hypothetical drought period, base flows at the Sweetwater (07301420), Carter (07301500), Headrick (07305000), and Snyder (07307010) streamgages had decreased by about 37, 61, 44, and 45 percent, respectively. The minimum Lake Altus storage simulated during the drought period was 403 acre-feet, which was a decline of 92 percent from the nondrought storage. Reduced base flows in the North Fork Red River were the primary cause of Lake Altus storage declines.

Oklahoma↗
USGS1976

Water resources of south-central Missouri

This atlas describes hydrology in an area of approximately 23 ,000 sq mi and includes all or parts of 38 counties in Missouri. The area is bounded on the north by the southern edge of the Missouri River flood plain, on the east by the Mississippi River and the Plateaus-Lowlands boundary (Ozark Escarpment), on the south by the Missouri-Arkansas State line, and on the west by the western drainage divides of the Gasconade and White River basins. The alluvial valley of the Missouri River is excluded. Although the populations of several rural counties in the area have declined in recent years, significant population increases have occurred in the vicinity of the two principal population centers, St. Louis in the northeast and Springfield in the southwest. Future population increases are expected to occur as a result of continued urban expansion, increased recreational use of land and water resources, and additional development of the mining industry. (Woodard-USGS)

Hydrologic Atlas↗
USGS1980

Hydrologic monitoring program in Eldridge-Wilde and East Lake Road well-field areas, Pinellas and Hillsborough counties, Florida, 1977 water year

The observation-well network in the vicinity of the two well fields is described in detail. Data obtained from the network from October 1976 through September 1977, as well as rainfall and pumpage records, are presented and discussed. Below-normal rainfall caused the water table and potentiometric surface of the Floridan aquifer in Eldridge-Wilde well field to recover 2 feet less in September 1977 than in the previous September. Water levels in East Lake Road will field were approximately the same in September of both years. The Southwest Florida Water Management District has established regulatory water-level and water-quality limits in several observation wells. Water levels did not drop below regulatory limits during the year. Water from two deep wells west of Eldridge-Wilde well field exceeded the regulatory limits for chloride concentrations. The position of the 250 milligram per liter chloride line is shown in cross section in the vicinity of Eldridge-Wilde well field in September 1977. Network modifications are proposed that would result in a more comprehensive knowledge of the hydrologic system.

Florida↗
USGS1996

Initiation and frequency of debris flows in Grand Canyon, Arizona

Debris flows occur in 600 tributaries of the Colorado River in Grand Canyon, Arizona when intense precipitation causes slope failures in bedrock or colluvium. These slurries transport poorly sorted sediment, including very large boulders that form rapids at the mouths of tributaries and control the longitudinal profile of the Colorado River. Although the amount of rainfall on the days of historic debris flows typically is not unusual, the storm rainfall on consecutive days before the debris flows typically had recurrence intervals greater than 10 yrs. Four types of failure mechanisms initiate debris flows: bedrock failure (12 percent), failure of colluvial wedges by rainfall (21 percent), failure of colluvial wedges by runoff (the "firehose effect;" 36 percent), and combinations of these failure mechanisms (30 percent). Failure points are directly or indirectly associated with terrestrial shales, particularly the Permian Hermit Shale, shale units within the Permian Esplanade Sandstone of the Supai Group, and the Cambrian Bright Angel Shale. Shales either directly fail, produce colluvial wedges downslope that contain clay, or form benches that store poorly sorted colluvium in wedge-shaped deposits. Terrestrial shales provide the fine particles and clay minerals-particularly kaolinite and illite-essential to long-distance debris-flow transport, whereas marine shales mostly contain smectites, which inhibit debris-flow initiation. Using repeat photography, we determined whether or not a debris flow occurred in the last century in 164 of 600 tributaries in Grand Canyon. We used logistic regression to model the binomial frequency data using 21 morphometric and lithologic variables. The location of shale units, particularly the Hermit Shale, within the tributary is the most consistent variable related to debris-flow frequency in Grand Canyon. Other statistically significant variables vary with large scale changes in canyon morphology. Standard morphometric measures such as drainage-basin area, channel gradient, and aspect of the river corridor are the most significant variables in the narrow and deep eastern section of Grand Canyon. Measures of the location of source lithologies are more important in western Grand Canyon, which has broader and low-gradient drainages. Measures of geologic structure, and other standard hydrologic variates, were not significant. Our results show that the probability of debris-flow occurrence is highest in eastern Grand Canyon. Throughout Grand Canyon, the probability of debris-flow occurrence is highest in reaches of the Colorado River that trend south-southwest. This direction is significant because most summer storms originate from a southerly direction, and the maximum slope of the regional structure is to the southwest. The binomial frequency of debris flows is not random in Grand Canyon, and tributaries of similar debris-flow frequency are clustered in distinct reaches.

Arizona↗
USGS1974

Floodflow characteristics of Fourche Creek at Interstate Highway 430, in southwest Little Rock, Arkansas

The Arkansas State Highway Department is constructing Interstate Highway 430 (1-430) across Fourche Creek in southwest Little Rock. The Highway Department requested the U.S. Geological Survey to determine the elevation, the discharge, and the frequency of the flood of April 21, 1974, and the elevation, the discharge, and the backwater for the 50-year flood, and to report on the hydrologic effects of alterations to the proposed bridges and roadway to accommodate the larger of the two floods. All elevations in this report are given to highway datum, which is mean sea level. This report was prepared under the provisions of the cooperative agreement between the Arkansas State Highway Commission and the Geological Survey.

Arkansas↗
USGS1985

Estimating average base flow at low-flow partial-record stations on the south shore of Long Island, New York

Base flows of the 29 major streams in southeast Nassau and southwest Suffolk Counties, New York, were statistically analyzed to discern the correlation among flows of adjacent streams. Concurrent base-flow data from a partial-record and a nearby continuous-record station were related; the data were from 1968-75, a period near hydrologic equilibrium on Long Island. The average base flow at each partial-record station was estimated from a regression equation and average measured base flow for the period at the continuous-record stations. Regression analyses are presented for the 20 streams with partial-record stations. Average base flow of the nine streams with a continuous record totaled 90 cu ft/sec; the predicted average base flow for the 20 streams with a partial record was 73 cu ft/sec (with a 95% confidence interval of 63 to 84 cu ft/sec.) Results indicate that this method provides reliable estimates of average low flow for streams such as those on Long Island, which consist mostly of base flow and are geomorphically similar. (USGS)

Water-Resources Investigations Report↗
USGS2006

A preliminary evaluation of vertical separation between production intervals of coalbed-methane wells and water-supply wells in the Raton basin, Huerfano and Las Animas Counties, Colorado, 1999-2004

The Raton Basin in southern Colorado and northern New Mexico is undergoing increased development of its coalbed-methane resources. Annual production of methane from coalbeds in the Raton Basin in Huerfano and Las Animas Counties, Colorado, increased from about 28,000,000 thousand cubic feet from 478 wells to about 80,000,000 thousand cubic feet from 1,543 wells, during 1999-2004. Annual ground-water withdrawals for coalbed-methane production increased from about 1.45 billion gallons from 480 wells to about 3.64 billion gallons from 1,568 wells, during 1999-2004. Where the coalbeds are deeply buried near the center of the Raton Basin, water pressure may be reduced as much as 250 to 300 pounds per square inch to produce the methane from the coalbeds, which is equivalent to a 577- to 692-foot lowering of water level. In 2001, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began an evaluation of the potential effects of coalbed- methane production on the availability and sustainability of ground-water resources. In 2003, there were an estimated 1,370 water-supply wells in the Raton Basin in Colorado, and about 90 percent of these water-supply wells were less than 450 feet deep. The tops of the production (perforated) interval of 90 percent of the coalbed-methane wells in the Raton Basin (for which data were available) are deeper than about 675 feet. The potential for interference of coalbed-methane wells with nearby water-supply wells likely is limited because in most areas their respective production intervals are separated by more than a hundred to a few thousand feet of rock. The estimated vertical separation between production intervals of coalbed-methane and water-supply wells is less than 100 feet in an area about 1 to 6 miles west and southwest of Trinidad Lake and a few other isolated areas. It is assumed that in areas with less than 100 feet of vertical separation, production by coalbed-methane wells has a greater potential for interfering with nearby water-supply wells. More detailed geologic and hydrologic information is needed in these areas to quantify the potential effects of coalbed-methane production on water levels and the availability and sustainability of ground-water resources.

Scientific Investigations Report↗
USGS1974

Water in the Great Basin region; Idaho, Nevada, Utah, and Wyoming

The Great Basin Region is defined to include the drainage of the Great Basin physiographic section (Fennman, 1931) in Idaho, Nevada, Utah, and Wyoming. In October 1966, the President’s Water Resources Council requested that a comprehensive framework study be made in the Great Basin Region under the leadership of the Pacific Southwest Interagency Committee. The study, which included evaluation of the water resources of the region and guidelines for future study and development, was completed June 30, 1971. Results of the study received limited distribution. The purpose of this atlas is to make available to the public the hydrologic data (including a general appraisal) that were compiled for the comprehensive framework study. Most of the work was done by a water-resources work group consisting of members from several Federal and State agencies under the chairmanship of Thomas E. Eakin of the U.S. Geological Survey. This atlas contains some data not included in the framework study. The data presented herein are reconnaissance in nature and should be used with discretion. The maps are highly generalized and are intended only to illustrate the regional distribution of the supply and general chemical quality of the water. Sources of more detailed information on the hydrology of specific parts of the Great Basin region are listed in the selected references.

Idaho, Nevada, Utah, Wyoming↗
USGS1980

A water-quality monitoring network for Vallecitos Valley, Alameda County, California

A water-quality monitoring network is proposed to detect the presence of and trace the movement of radioisotopes in the hydrologic system in the vicinity of the Vallecitos Nuclear Center. The source of the radioisotopes is treated industrial wastewater from the Vallecitos Nuclear Center that is discharged into an unnamed tributary of Vallecitos Creek. The effluent infiltrates the alluvium along the stream course, percolates downward to the water table, and mixes with the native ground water in the subsurface. The average daily discharge of effluent to the hydrologic system in 1978 was about 100,000 gallons. In Vallecitos Valley, the Livermore Gravel and the overlying alluvium constitute the ground-water reservoir. There is no subsurface inflow from adjacent ground-water basins. Ground-water flow in the Vallecitos subbasin is toward the southwest. The proposed network consists of four surface-water sampling sites and six wells to sample the ground-water system. Samples collected monthly at each site and analyzed for tritium and for alpha, beta, and gamma radiation would provide adequate data for monitoring.

California↗
USGS2014

Ground‐water studies in the Southwest

Geologists are concerned with the rock‐systems that form the crust of the Earth. The groundwater geologists are concerned with the rock‐systems specifically because the open spaces which the rocks contain serve as reservoirs and conduits for water—water which performs a large part of the geologic work that is in progress today and has been in progress during past ages; water which affects profoundly the whole hydrologic cycle and is still the principal source of water‐supply for mankind, as it has been for primitive man and the other land animals before the time of artificial waterworks.

Eos, Transactions, American Geophysical Union↗
USGS2017

Millennial-scale variability in the local radiocarbon reservoir age of south Florida during the Holocene

A growing body of research suggests that the marine environments of south Florida provide a critical link between the tropical and high-latitude Atlantic. Changes in the characteristics of water masses off south Florida may therefore have important implications for our understanding of climatic and oceanographic variability over a broad spatial scale; however, the sources of variability within this oceanic corridor remain poorly understood. Measurements of ΔR, the local offset of the radiocarbon reservoir age, from shallow-water marine environments can serve as a powerful tracer of water-mass sources that can be used to reconstruct variability in local-to regional-scale oceanography and hydrology. We combined radiocarbon and U-series measurements of Holocene-aged corals from the shallow-water environments of the Florida Keys reef tract (FKRT) with robust statistical modeling to quantify the millennial-scale variability in ΔR at locations with (“nearshore”) and without (“open ocean”) substantial terrestrial influence. Our reconstructions demonstrate that there was significant spatial and temporal variability in ΔR on the FKRT during the Holocene. Whereas ΔR was similar throughout the region after ∼4000 years ago, nearshore ΔR was significantly higher than in the open ocean during the middle Holocene. We suggest that the elevated nearshore ΔR from ∼8000 to 5000 years ago was most likely the result of greater groundwater influence associated with lower sea level at this time. In the open ocean, which would have been isolated from the influence of groundwater, ΔR was lowest ∼7000 years ago, and was highest ∼3000 years ago. We evaluated our open-ocean model of ΔR variability against records of local-to regional-scale oceanography and conclude that local upwelling was not a significant driver of open-ocean radiocarbon variability in this region. Instead, the millennial-scale trends in open-ocean ΔR were more likely a result of broader-scale changes in western Atlantic circulation associated with an increase in the supply of equatorial South Atlantic water to the Caribbean and shifts in the character of South Atlantic waters resulting from variation in the intensity of upwelling off the southwest coast of Africa. Because accurate estimates of ΔR are critical to precise calibrations of radiocarbon dates from marine samples, we also developed models of nearshore and open-ocean ΔR versus conventional 14 C ages that can be used for regional radiocarbon calibrations for the Holocene. Our study provides new insights into the patterns and drivers of oceanographic and hydrologic variability in the Straits of Florida and highlights the value of the paleoceanographic records from south Florida to our understanding of Holocene changes in climate and ocean circulation throughout the Atlantic.

Florida↗
USGS1980

Preliminary report on the hydrogeology of a low-level radioactive waste disposal site near Sheffield, Illinois

The Sheffield low-level radioactive-waste disposal site is located on 20 acres of rolling terrain about 3 miles southwest of Sheffield, Illinois. Twenty-one trenches were constructed and filled with radioactive waste from August 1967 through April 1978. Forty-three test wells were installed by the U.S. Geological Survey on and adjacent to the site. Continuous cores were collected from 36 wells to help in defining the subsurface geology. The wells have been used for water sample collection and to monitor water-level changes. A tunnel. 6.5 feet in diameter by 290 feet in length, was constructed beneath four burial trenches to provide access for collection of hydrologic and geologic data. Pennsylvanian shale and mudstone deposits are overlain by Pleistocene glacial deposits consisting of the Teneriffe Silt, Glasford Formation, Roxana Silt, Peoria Loess, Parkland Sand, Cahokia Alluvium, and Henry Formation. Three till units of the Glasford Formation, the Hulick Till Member, the Radnor Till Member, and Till A have been identified on the site. Stratigraphic position indicates that the Hulick Till Member and Till A are probably variations of the same till. A continuous pebbly sand deposit, classified as part of the Toulon Member, extends across the middle of the site and continues off site on the northeast and southwest corners. Because of its relatively high hydraulic conductivity, this deposit will be a controlling factor in shallow groundwater movement and in any radionuclide migration. Ground water at the site is derived through infiltration of precipitation and as underflow from adjacent highlands. Precipitation averages 35 inches per year, 1 or 2 inches of which probably recharge the ground water. Runoff is estimated to be 12 to 15 inches per year and evapotranspiration about 20 inches. The fluctuation of water levels has been about 2.5 feet in hilltop wells, 3.6 feet in sidehill wells, and 5.9 feet in valley wells. Hydraulic conductivity of the materials comprising the hydrogeologic system vary widely from about 2.8 to 2.8 x 10 -6 feet/day. Tritium in ground water near the southeast corner of the site has moved about 25 feet per year since June 1975.

Illinois↗
USGS2002

Flood pulsing in wetlands: Restoring the natural hydrological balance

The latest cutting-edge research on flood pulsing and wetland restoration in North America. Presenting the latest research from leaders in the field of restoration ecology, Flood Pulsing in Wetlands reflects the current movement to incorporate flood pulsing into wetland restoration efforts. Emphasizing how integral flood pulsing is to successful wetland restoration, the book's contributors provide descriptions of restoration projects across North America in which flood pulsing has been primarily used to restore beneficial hydrodynamic conditions to floodplain areas, and improve or save vegetation, wildlife, and terrain. Detailing the importance and applicability of recreating flood-pulsed conditions on floodplains for successful restoration, the first chapter introduces the concept of flood pulse and its unique role in wetland restoration. The following chapters detail the strategies and results of individual projects and the impact flood pulsing had on the projects' overall goals. Case studies detail the history of each region, such as the Southwest, including the Sonoran Desert communities and the Middle Rio Grande; the Missouri River in Montana; the Illinois River Valley; and the Southeast, including Brushy Lake, Arkansas. Also documented is the most famous case of flood pulsing used in the restoration of an entire landscape, the Kissimmee River project. Approaches used to restore specific plant and animal populations, the unique ecological concerns of each region, and the future outlook for each area are fully described. Extensive bibliographies for each chapter make Flood Pulsing in Wetlands: Restoring the Natural Hydrological Balance the essential reference for restoration ecologists, consultants in wetland restoration, government and restoration agency employees, land managers, ecologists, foresters, and geologists.

Book↗
USGS1980

Hydrologic monitoring program in Eldridge-Wilde and East Lake Road well-field areas, Pinellas and Hillsborough counties, Florida, 1978

This report describes the observation-well network in Eldridge-Wilde and East Lake Road well-field areas, Pinellas and Hillsborough Counties, Florida. Data obtained in 1978 from the network in and adjacent to the two well fields, as well as rainfall and pumpage records, are presented. The Southwest Florida Water Management District has established regulatory water-level limits in four observation wells and water-quality limits in three observation wells. Water levels dropped below regulatory limits in the spring of 1978 in three wells. Chloride concentrations in 1978 remained above regulatory limits for the entire year in one well and exceeded the limit during the late spring in the other two deep wells, both west of Eldridge-Wilde well field. (USGS)

Open-File Report↗
USGS1989

Analysis of the effect of pumping on ground-water flow in the Springfield Plateau and Ozark aquifers near Springfield, Missouri

Pumpage of water from the Ozark aquifer for public supply and industry use by the city of Springfield and surrounding communities in southwestern Missouri has significantly altered the potentiometric surface of the aquifer. Springfield is located on a regional groundwater divide that trends east and west across southern Missouri. Groundwater that once flowed north and south from the divide now moves toward Springfield. Drawdown in the Ozark aquifer beneath Springfield has increased about 50 ft near the center of the city since 1974. The area of well influence also has increased, most notably to the south and southwest, because of increased pumpage by Springfield and new groundwater withdrawals in rapidly increasing communities, such as Republic and Nixa. Changes in the potentiometric surface of the Ozark aquifer, and to a lesser extent the Springfield Plateau aquifer, resulting from stresses applied by pumpage of water supply wells has altered the hydrologic budget of the Springfield area. Downward leakage of groundwater through the Ozark confining unit has increased from about 10 cu ft/sec to about 18 cu ft/sec because drawdown in the Ozark aquifer has resulted in an increased vertical hydraulic gradient across the confining unit. Minimal quantities of water are supplied by increased upward leakage through the St. Francois confining unit. Model simulations indicate substantial quantities of water are still (1987) being removed from storage within the Ozark and Springfield Plateau aquifers and the hydrologic system is not in equilibrium at this time. (USGS)

Water-Resources Investigations Report↗
USGS2001

Analysis of streambed temperatures in ephemeral channels to determine streamflow frequency and duration

Spatial and temporal patterns in streamflow are rarely monitored for ephemeral streams. Flashy, erosive streamflows common in ephemeral channels create a series of operational and maintenance problems, which makes it impractical to deploy a series of gaging stations along ephemeral channels. Streambed temperature is a robust and inexpensive parameter to monitor remotely, leading to the possibility of analyzing temperature patterns to estimate streamflow frequency and duration along ephemeral channels. A simulation model was utilized to examine various atmospheric and hydrological upper boundary conditions compared with a series of hypothetical temperature‐monitoring depths within the streambed. Simulation results indicate that streamflow events were distinguished from changing atmospheric conditions with greater certainty using temperatures at shallow depths (e.g., 10–20 cm) as opposed to the streambed surface. Three ephemeral streams in the American Southwest were instrumented to monitor streambed temperature for determining the accuracy of using this approach to ascertain the long‐term temporal and spatial extent of streamflow along each stream channel. Streambed temperature data were collected at the surface or at shallow depth along each stream channel, using thermistors encased in waterproof, single‐channel data loggers tethered to anchors in the channel. On the basis of comparisons with site information, such as direct field observations and upstream flow records, diurnal temperature variations successfully detected the presence and duration of streamflow for all sites.

Water Resources Research↗
USGS2025

Groundwater hydrology, groundwater and surface-water interactions, water quality, and groundwater-flow simulations for the Wet Mountain Valley alluvial aquifer, Custer and Fremont Counties, Colorado, 2017–19

In 2017, the U.S. Geological Survey, in cooperation with the Upper Arkansas Water Conservancy District, began a study to provide a comprehensive analysis of the Wet Mountain Valley alluvial aquifer, Custer and Fremont Counties, Colorado. The study included collection of data pertaining to groundwater hydrology, groundwater and surface-water interactions, and water quality in the alluvial aquifer. In addition to providing foundational information on the hydrology of the alluvial aquifer, a numerical groundwater-flow model was developed to estimate the potential effects of additional storage of groundwater in the alluvial aquifer. Groundwater-level elevation data from 30 wells were used to estimate groundwater-flow directions in the alluvial aquifer, which were generally from the southwest to northeast, away from the Sangre de Cristo Mountains and towards perennial streams in the center of the valley. Although some seasonal variation was apparent in groundwater-level elevation records, no statistically significant seasonal trends were indicated. Statistically significant long-term trends were indicated in groundwater-level elevation records for 8 of the 30 wells, and of these wells with statistically significant trends, all but 1 indicated a negative trend of groundwater-level elevations. Spatial evaluation of wells with statistically significant negative groundwater-level elevation trends showed many are in areas of denser well drilling for domestic or other uses, indicating increasing groundwater use could potentially be causing groundwater-level elevation declines. There were instances of wells with no statistically significant groundwater-level elevation trends also located in areas of greater density of well completions. Additional investigations may be necessary to more fully characterize the processes responsible for negative groundwater-level elevation trends. Streamflow gain or loss calculations were completed for low flow in 2017–19 and for high flow in 2018 in nine reaches of streams within the study area. Stream reaches of the upper Texas Creek, upper Grape Creek, upper-middle Grape Creek, and Taylor Creek displayed consistent streamflow loss in each period from 2017 to 2019. These stream reaches represent long-term sources of recharge to the alluvial aquifer. Streamflow gain or loss varies through time in other stream reaches (lower Texas Creek, lower-middle Grape Creek, lower Grape Creek below Westcliffe, and lower Grape Creek above DeWeese Reservoir). The temporally variable behavior indicates these stream reaches may be sources of groundwater recharge or areas of groundwater discharge, likely depending on temporal dynamics between the elevation of the water table and the stream. Water-quality samples were collected from 10 groundwater wells and 10 stream sites during September through November 2019. All groundwater and stream samples were analyzed for major and trace elements and stable isotopes of water. A subset of groundwater samples was also analyzed for the environmental tracers sulfur hexafluoride, tritium, and noble gases. Comparison of water-quality results to U.S. Environmental Protection Agency drinking water-quality standards indicated no constituents exceeded primary standards for human health. Spatial evaluation of water quality indicated the concentrations of various constituents are likely controlled by groundwater and surface-water interactions and by spatial variability in bedrock geology underlying the alluvial aquifer. Specifically, streams shown to gain from groundwater had water chemistry constituent compositions similar to groundwater, whereas streams exiting the Sangre de Cristo Mountains tended to have compositions consistent with snowmelt. Groundwater geochemistry appeared to be partially controlled by oxidation-reduction processes and by proximity to igneous rocks in the Wet Mountains. Environmental tracers used to estimate groundwater age indicated all sampled groundwater contained tracers representing modern recharge (approximately less than 65 years old) but mixing of premodern recharge (approximately more than 65 years old) also occurs. Spatial evaluation of environmental tracers indicated large faults may be conduits for upwelling of older groundwater. No trends were observed in groundwater age with well depth, indicating all sampled wells are located within the zone of active groundwater flow. The presence of modern groundwater in wells with statistically significant negative groundwater-level elevation trends indicates groundwater storage depletions may be partially offset by capture of modern recharge. Repeated sampling of groundwater age would be necessary, however, to determine if any trends in groundwater age exist, which may indicate changing groundwater recharge, storage, or discharge. Additional investigations could also consider quantifying groundwater age in deeper wells to more fully define the depth of active groundwater flow. A numerical groundwater-flow model was developed to estimate components of the water budget, simulate groundwater and surface-water interactions, and evaluate the potential effects of aquifer storage and recovery. Simulated groundwater-level elevations from the calibrated groundwater-flow model are similar to the observed pattern of groundwater-level elevations with higher elevations in the western part of the study area along the Sangre de Cristo Mountains. Simulated water-budget components indicate most of the recharge to the alluvial aquifer is derived from streamflow losses, which is consistent with observations of losing streams along the mountain front. The largest groundwater discharge component of the alluvial aquifer was to streams in the center of the valley, where observations of stream gain or loss indicated the predominance of gaining conditions. Comparison of groundwater and surface-water interactions between the calibrated groundwater-flow model for 2000-19 (the base-case model) and a simulation including additional recharge, representing potential aquifer storage and recovery operations, indicated the additional recharge distributed throughout the area had minimal effects on streamflow in the nearby Grape Creek. An analysis of subregional groundwater budgets showed approximately 54 percent of the additional recharge flowed back to nearby Grape Creek, and the other 46 percent was distributed laterally into adjacent cells in the alluvial aquifer. The comparison of simulations and subregional water budget show the additional recharge did not substantially alter groundwater-level elevations or basin wide groundwater storage. Although the analysis of additional recharge provided in the numerical groundwater-flow model considers only one of many possible recharge scenarios, the model provides a useful tool that could be modified for various scenarios to understand potential effects of managed aquifer recharge.

Colorado↗
USGS1989

Appalachian Piedmont landscapes from the Permian to the Holocene

Between the Potomac and Susquehanna Rivers and from the Blue Ridge to the Fall Zone, landscapes of the Piedmont are illustrated for times in the Holocene, Late Wisconsin, Early Miocene, Early Cretaceous, Late Triassic, and Permian. Landscape evolution took place in tectonic settings marked by major plate collisions (Permian), arching and rifting (Late Triassic) and development of the Atlantic passive margin by sea floor spreading (Early Cretaceous). Erosion proceeded concurrently with tectonic uplift and continued after cessation of major tectonic activity. Atlantic Outer Continental Shelf sediments record three major erosional periods: (1) Late Triassic-Early Jurassic; (2) Late Jurassic-Early Cretaceous; and (3) Middle Miocene-Holocene. The Middle Miocene-Holocene pulse is related to neotectonic activity and major climatic fluctuations. In the Piedmont upland the Holocene landscape is interpreted as an upland surface of low relief undergoing dissection. Major rivers and streams are incised into a landscape on which the landforms show a delicate adjustment to rock lithologies. The Fall Zone has apparently evolved from a combination of warping, faulting, and differential erosion since Late Miocene. The periglacial environment of the Late Wisconsin (and earlier glacial epochs) resulted in increased physical erosion and reduced chemical weathering. Even with lowered saprolitization rates, geochemical modeling suggests that 80 m or more of saprolite may have formed since Late Miocene. This volume of saprolite suggests major erosion of upland surfaces and seemingly contradicts available field evidence. Greatly subdued relief characterized the Early Miocene time, near the end of a prolonged interval of tropical morphogenesis. The ancestral Susquehanna and Potomac Rivers occupied approximately their present locations. In Early Cretaceous time local relief may have been as much as 900 m, and a major axial river draining both the Piedmont and Appalachians flowed southeast past Baltimore. The Late Triassic landscape was influenced by rift basin development. Streams drained into a hydrologically closed basin: no through-flowing rivers seem to have been present. A limestone escarpment along the Blue Ridge may have existed as a consequence of a semi-arid climate. The Permian may have been a time of Himalayan-like mountains and mountain glaciers. Streams (and glaciers) generally flowed southwest and west. ?? 1989.

Geomorphology↗