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At least 1,369 records · Page 76Linked to original sources
USGS2004

Surface- and Ground-Water Monitoring and Mapping of Selected Features at the Blue Ridge Parkway Mt. Pisgah Campground, Haywood County, North Carolina, 2002

During 2002, a baseline study of hydrologic conditions was conducted, and selected features were mapped within the Mt. Pisgah campground on the Blue Ridge Parkway in Haywood County, North Carolina. Field surveys were performed by using global positioning system equipment one time (January 2002) during the study to locate hydrologic and other types of features in the study area. Water-level and streamflow data and seasonal water-quality samples were collected from a stream that receives all surface-water drainage from the campground area. During 2002, water levels (stage) in the stream ranged from 1.09 to 1.89 feet above gage datum (4,838.06 to 4,838.86 feet above mean sea level). Flow in the stream ranged from 0.05 to 9.7 cubic feet per second. Annual daily mean flow for calendar year 2002 was approximately 0.35 cubic foot per second (about 226,000 gallons per day). Samples collected from the stream had low concentrations of all constituents measured. Four compounds associated with human activity (camphor, N,N-diethyl-meta-toluamide (the insect repellent DEET), tributylphosphate, and methylsalicylate) were detected in the stream samples; however, concentrations were less than detection levels. Stream samples collected in April and September and analyzed for fecal coliform bacteria had densities of 76 and 110 colonies per 100 milliliters of water, respectively. No violations of water-quality standards were noted for any constituent measured in the stream samples. Seven shallow ground-water wells were installed near a natural area in the center of the campground. Ground-water levels measured periodically in these wells and in two existing shallow piezometers generally were highest in the spring and lowest in the fall. Water temperature, pH, and specific conductance were measured in samples collected from the shallow wells in April and September 2002. Measured pH values were consistently lowest in samples from two wells on the west side of the natural area and highest in samples from the well located near the center of the natural area. Specific-conductance values measured in samples from wells on the east side of the natural area were lower than those measured in samples from the other wells. Specific-conductance values measured in samples from two wells on the west side and from one well near the center of the natural area generally were two to three times higher than the specific-conductance values measured in samples from wells on the east side of the natural area. Samples for fecal coliform bacteria were collected from six wells on September 11, 2002. The fecal coliform densities in samples from most of the wells were less than or equal to 8 colonies per 100 milliliters. Samples from two of the three wells on the west side of the natural area had coliform densities of 16 and 480 colonies per 100 milliliters. Other ground-water samples collected on September 11 and September 24 were analyzed with a spectrophotometer in the U.S. Geological Survey (USGS) North Carolina District Office for nitrate concentrations only. From the samples collected on September 11, estimated nitrate concentrations of 1 milligram per liter or less were detected in three wells, two on the west side and one on the east side of the natural area. Nitrate was not detected with a spectrophotometer in any of the ground-water samples collected on September 24. Indicator test strips also were used in the field to screen for nitrate and nitrite in ground-water samples collected on September 24. Nitrate was detected by test strips in one well on the west side of the natural area, with estimated concentrations of 1 milligram per liter or less indicated. Nitrite was not detected by the test strips in samples collected from any of the wells.

North Carolina↗
USGS2008

U.S. Geological Survey Science Support Strategy for Biscayne National Park and Surrounding Areas in Southeastern Florida

The U.S. Geological Survey conducts a wide range of research in and around the Biscayne National Park region of southern Florida. This research encompasses the biologic, ecologic, meteorologic, geologic, and hydrologic components of the system, including water-quality analyses, ground-water modeling, hydrogeologic-data collection, ecologic-habitat evaluations, wetlands characterizations, biogeochemistry of ecosystems, and paleo-ecologic analyses. Relevant information is provided herein for researchers and managers interested in the Biscayne Bay area and about current U.S. Geological Survey efforts that address important resource protection and management issues. Specifically, managers and scientists are provided with information on current and recently completed U.S. Geological Survey projects and a sample listing of potential U.S. Geological Survey research projects addressing relevant issues that face the study area.

Open-File Report↗
USGS1972

Records of water-level measurements in wells in the Oklahoma panhandle, 1971-72

Investigations of the ground-water resources of the Oklahoma panhandle by the U.S. Geological Survey in cooperation with the Oklahoma Water Resources Board includes collection of water-level records; the systematic collection of these records began in 1937. Records of many shallow wells were compiled in 1937 and periodic measurements were made in a few wells until 1966. Owing to the heavy development of irrigation during the 1960's (fig. 1) an expanded network of observation wells established in Texas County in 1966 and in Beaver and Cimarron Counties in 1967; measurement of water levels have been made on an annual basis since those times. This report contains water-level records for the period 1971-72 and the water-level change for the period 1966-72 in Texas County, and for the period 1967-72 in Beaver and Cimarron Counties. At the present time (1972) the annual observation-well network includes 521 wells, of which 97 are in Beaver County, 203 are in Cimarron County, and 221 are in Texas County. These data provide an index to available ground-water supplies; they will be useful in planning and studying water resources development; and they will serve as a framework of data for the detailed hydrologic investigation now in progress in the panhandle.

Oklahoma↗
USGS1982

Background hydrologic information in potential lignite mining areas in Mississippi, August 1981

The U.S. Geological Survey in cooperation with the Mississippi Bureau of Geology is conducting a hydrologic data-collection program in potential lignite-producing areas in Mississippi. During the period August 24-31, 1981, hydrologic data consisting of channel characteristics and stream discharge were collected at 18 sites, and water and channel bottom material samples were collected at 15 sites on small streams draining potential lignite mining areas in east-central Mississippi. Main channel widths ranged from 100 feet on Mill Creek near Louisville to 30 feet on Spring Creek near Bond. Maximum water depths varied from 12.5 feet on Pawticfaw Creek to 0.2 foot on Beasha Creek. Three sites had no discharge. Specific conductance ranged from 100 micromhos on Lonsilocher Canal near Philadelphia to 24 micromhos on Jofuska Creek near Arlington. Water temperatures varied from 22.5 to 26 degrees Celsius. The highest pH was 7.6 on Fulton and Lonsilocher Canals. The dissolved oxygen concentration was 3.8 milligrams per liter or higher at all sites. Channel bottom-material samples commonly contained iron, manganese, and zinc. (USGS)

Open-File Report↗
USGS1984

Illinois ground-water observation network; a preliminary planning document for network design

Water-level and water-quality networks in Illinois were evaluated to determine the adequacy and completeness of available data bases. Ground-water data in present data bases are inadequate to provide information on ground-water quality and water levels in large areas of Illinois and in the major geohydrologic units underlying Illinois and surrounding areas. Data-management needs indicate that a new data base is desirable and could be developed by use of carefully selected available data and new data. Types of data needed to define ground-water quality and water levels in selected geohydrologic units were tentatively identified. They include data on concentrations of organic chemicals related to activities of man, and concentrations of inorganic chemicals which relate either to man 's activities or to the chemical composition of the source aquifer. Water-level data are needed which can be used to describe short- and long-term stresses on the ground-water resources of Illinois. Establishment of priorities for data collection has been deferred until existing hydrologic data files can be stored for usable data and until input from other local, State, and Federal agencies can be solicited and compiled. (USGS)

Open-File Report↗
USGS1985

Use and availability of continuous streamflow records in New Mexico

The use and availability of data collected at streamflow gaging stations in New Mexico is documented as the first phase of a three phase study of the cost-effectiveness of the stream gaging program. Presently, 143 continuous gaging stations are operated. Data collected at most gaging stations have multiple uses. Many stations are operated under the terms of eight legal compacts and two court decrees. These data provide the basis for distribution of irrigation water and operation of dams. Data from six stations are used for forecasting flood conditions. Water quality data are collected at many of the stations, ten of which have been designated as part of a national network of water quality data monitoring and two under the benchmark program. Data useful in the defining regional hydrology have been collected at a majority of the stations. All stations presently (1984) have sufficient justification for continued operations. (USGS)

Open-File Report↗
USGS1989

Summary of the U.S. Geological Survey and U.S. Bureau of Land Management national coal-hydrology program, 1974-84

During the decade 1974-84, the U.S. Geological Survey and the U.S. Bureau of Land Management cooperated on investigations to collect information and to study hydrologic processes related to development and mining of federally owned coal. In addition, the U.S. Geological Survey conducted similar investigations related to nonfederally owned coal. As a result of these nationwide investigations, a large quantity of hydrologic information and data has been collected and compiled in more than 500 reports. This report summarizes the major findings and accomplishments that have resulted from data-collection activities, hydrologic studies, and research concerned with the effects of coal mining on water resources. This summary report includes: (1) A description of the Nation's coal and water-resource issues related to coal development, including history, objectives, and design of the coal-hydrology program; (2) a summary of the hydrologic information collected in the major coal provinces and published in more than 500 reports and journal articles; and (3) a summary and application of results obtained from topical studies undertaken throughout the program, including discussions on watershed modeling, salinity modeling, ground-water flow systems, geochemistry of mine spoils, mine drainage, sedimentation, and aquatic biology. A detailed coal-hydrology reference list concludes the report.

continental United States↗
USGS2020

Assessment of soil and water resources in the Organ Mountains-Desert Peaks National Monument, New Mexico

The Organ Mountains-Desert Peaks National Monument (Monument) in southern New Mexico was established in 2014. Given anticipated future demands in the Monument for recreation, livestock grazing, and maintenance of rights-of-way (for example, pipelines and powerlines), the Bureau of Land Management (BLM) needs a better understanding of the current soil and water resources and how infrastructure improvements could affect these resources and the watershed. Specifically, the BLM is concerned with infiltration and erosion and their relations to existing or planned infrastructure, such as roads, campgrounds, location of livestock grazing, and rights-of-way. Alternatives to the current land-use conditions, land-management practices, and infrastructure will be assessed by BLM to best protect Monument resources. The U.S. Geological Survey, in cooperation with the BLM, conducted a study to assess the soil and water resources within the Monument to provide an inventory and compilation of natural-resource information needed by resource managers for the BLM’s land-use planning process for this new national monument. The overall objectives of this study were to (1) compile and interpret existing soil- and water-resource data for the Monument and (2) provide a basic assessment of the surface hydrological effects of selected alternatives to current land use and infrastructure. Data were compiled by using geographic information system software and evaluated for hydrologic and landscape properties that influence infiltration, runoff, and erosion. The effects of changing vegetation were simulated by using different scenarios in the Rangeland Hydrology and Erosion Model. Results of this model indicate areas where soil loss or runoff may occur.

New Mexico↗
USGS2025

Spatial stream network modeling of water temperature within the White River Basin, Mount Rainier National Park, Washington

Water temperature is a primary control on the occurrence and distribution of fish and other ectothermic aquatic species. In the Pacific Northwest, cold-water species such as Pacific salmon ( Oncorhynchus spp.) and bull trout ( Salvelinus confluentus ) have specific temperature requirements during different life stages that must be met to ensure the viability of their populations. Rivers draining Mount Rainier in western Washington, including the White River along its northern flank, support a number of cold-water fish populations, but the spatial distribution of water temperatures, particularly during late-summer baseflow during August and September, and the climatic, hydrologic, and physical processes regulating it are not well constrained. Spatial stream network (SSN) models, which are generalized linear models that incorporate streamwise spatial autocovariance structures, were fit to mean and 7-day average daily maximum water temperature for August and September for the White River Basin. The SSN models were calibrated using water temperature measurements collected in 2010 through 2020. The extent of the models included the White River and its tributaries upstream from its confluence with Silver Creek in Mount Rainier National Park, Washington. SSN models incorporated covariates hypothesized to represent the climatic, hydrologic, and physical processes that influence water temperature. SSN models were fit to the measured data and compared to generalized linear models that lacked spatial autocovariance structures. Statistically significant covariates within the best-fit models included the proportion of ice cover and forest cover within the basin, mean August air temperature, the proportion of consolidated geologic units, and snow-water equivalent. Statistical models that included spatial autocovariance structures had better predictive performance than those that did not. Additionally, models of mean August and September water temperature had better predictive performance than those of 7-day average daily maximum temperature in August and September. Predictions of the spatial distribution of water temperature were similar between August and September with a general warming in the downstream part of the mainstem White River compared to cooler water temperatures in the high-elevation headwater streams. The proportion of ice cover emerged as an inversely related significant covariate to both mean August and September water temperature because streams that receive glacial meltwater are colder than non-glaciated streams. Water temperatures of the upper White River increased downstream and are attributed to warming of water temperature from accumulated solar radiation and inflow of non-glaciated tributaries. Estimated water temperatures for the upper White River model are 3–4 degrees Celsius (°C) warmer for tributaries, but 1–2 °C cooler for the mainstem compared to the regional-scale model. Differences between the upper White River SSN model and the regional-scale NorWeST model are attributed to the fact that the upper White River SSN included water temperature observations specific to the upper White River, whereas water temperature observations from lower elevation streams and downstream from the Mount Rainer National Park boundary were used in the regional scale model.

Washington↗
USGS2024

Advancing water security in Africa with new high-resolution discharge data

VegDischarge v1 is a comprehensive river discharge across Africa (2000–2021), produced by coupling the agro-hydrologic VegET model and the mizuRoute routing framework. Using remote sensing data and hydrological modeling, the 1-km runoff field simulated by VegET, and routed with mizuRoute, covers over 64,000 river segments in Africa. The VegET model simulates runoff based on vegetation and soil moisture dynamics, while mizuRoute processes this runoff through a detailed river network. Performance metrics show strong model reliability, with R² ranging from 0.5 to 0.9, NSE between 0.6 and 0.9, and KGE from 0.5 to 0.8. The total annual average discharge for Africa is quantified at 3238.1 km³ . year-1, with contributions to various oceanic basins: 989.9 km³ . year-1 to the North Atlantic, primarily from West African rivers like the Senegal, Gambia, Volta, and Niger; 1313.7 km³ . year-1 to the South Atlantic, largely from the Congo River; 212.5 km³ . year-1 to the Mediterranean Sea, predominantly from the Nile River; and 722.0 km³ . year-1 to the Indian Ocean, with substantial inputs from rivers such as the Zambezi. This VegDischarge v1 is valuable for policymakers, stakeholders, and researchers to better understand water availability, its temporal and spatial variations, that impact water-related infrastructure planning, sustainable resource allocation, and the development of climate resilience mitigation strategies.

Scientific Data↗
USGS1989

Hydrologic and geochemical monitoring in Long Valley caldera, Mono County, California, 1986

The U.S. Geological Survey continued to monitor hydrologic and geochemical conditions in the Long Valley caldera during 1986. The monitoring is directed toward detecting changes in the hydrologic system caused by tectonic or magmatic processes. Data collected during 1986 include chemical and isotopic composition of water from selected streams sites, springs, and wells; pumpage from four geothermal wells; flow rates of selected springs and stream sites; mean daily water or gas temperatures at selected sites; mean daily atmospheric pressures and water level at selected wells, and precipitation records for two sites. Seismicity within the caldera persisted at a relatively low level compared with the more active periods of 1978-84. The most significant events of seismicity that affected hydrologic monitoring sites in Long Valley during 1986 occurred during July , in response to the Chalfant Valley earthquakes, centered about 20 miles southeast of the caldera. Water level records for three wells show distinct responses to the Chalfant Valley earthquakes. (USGS)

Water-Resources Investigations Report↗
USGS1969

Hydrogeology of the Scioto River Valley near Piketon, south-central Ohio

A systematic study was made of one of Ohio's principal aquifers, a sand and gravel outwash in the Scioto River Valley, to determine the feasibility of developing a ground-water supply of 20 million gallons per day at a site near Piketon. The first part of the study was spent in determining the thickness and physical properties of the sand and gravel aquifer and in drilling test wells to determine the best site for the supply wells. The second part of the investigation was an aquifer infiltration test to determine the hydraulic properties of the aquifer and the conditions of stream recharge. A well 83 feet deep was drilled on the flood plain and was pumped for 9 days at the rate of 1,000 gallons per minute. Tile effect on the hydrologic system during and after the pumping was determined by measuring the water levels in an array of deep and shallow observation wells and in 8 drive-point wells installed in the bed of the river. Seldom have more comprehensive data been collected showing the effects of pumping on a natural, unconfined, hydrologic system. From these data were calculated the coefficient of transmissibility (215,000 gallons per day per foot) and the rate of streambed infiltration (0.235 million gallons per day per acre per foot). The aquifer was tested near the end of a long drought; so the ground-water levels and the river stage were very nearly following a level trend. Because the ground-water levels were essentially unaffected by extraneous influences, the test data are probably as precise and uncomplicated as is practical to obtain in the field. These data proved to be valid for use as design criteria for the location, spacing, and construction of four supply wells. The third part of the investigation was the testing and quantitative evaluation of the four supply wells before they were put into service. The wells were found to perform about as predicted, indicating that the hydraulic properties of the aquifer, as determined by standard methods, are fairly representative.

Ohio↗
USGS1975

Water and the South Florida environment

Ecological problems are a major concern to Florida as well as to the Nation. National attention was focused on these problems in September 1968, when the Port Authority of Dade County began to con- struct a jetport for supersonic aircraft on a 39-square-mile tract 6 miles north of Everglades National Park and on the east edge of the Big Cypress Swamp. Conservation groups and citizens raised questions as to the effects of a regional jetport and the attendant satellite growth on the water resources and biological communities of the National Park. The Department of the Interior began studies to investigate the situation. One study, Leopold (1969), reported on the unfavorable ecological effects of the attendant satellite growth. Then Secretary of the Interior, Walter J. Hickel, directed the U.S. Geological Survey to study the water resources of the Big Cypress to determine which parts of the Big Cypress contribute the major part of the water necessary to maintain adequate water supplies for Everglades National Park. This was done in a report by Klein and others (1970). At about the same time, the Departments of interior and Transportation, the State of Florida, and the Dade County Port Authority con-curred in assigning to the Secretary of the Interior certain responsibilities for planning, developing, and coordinating an ecological study of south Florida. A primary objective of the ecological study is to provide information that will assist in the formulation of land-use policy consistent with the protection of the environment of Everglades National Park, the adjacent estuaries, and the public water supplies. The part of the investigation describing the surface-water and ground-water resources of south Florida was assigned to the Geological Survey. The quantity and quality of surface water and ground water and their interrelation with estuarine and marine waters are here considered. Also considered are the problems, present or future, related to the hydrologic environment that involve human, animal, and plant life. Changes taking place, apparent trends, and projections for the future are also considered, as well as alternatives for water management. The Geological Survey effort began in January 1971, when aerial photography and selected qualitative hydrologic data were obtained. However, most of the information upon which this report Is based was obtained by the Geological Survey in cooperative programs with several local, State, and Federal agencies since about 1940. The long-term support of the U.S. Army Corps of Engineers, the National Park Service, U.S. Navy, Florida Department of Natural Resources, Central and Southern Florida Flood Control District, Dade, Broward, Palm Beach and Collier Counties, Miami and Miami Beach, Ft. Lauderdale, Naples and others in the collection of data is gratefully acknowledged. A prolonged drought throughout south Florida from September 1970 to May 1971 accentuated the importance and timeliness of the study. The drought brought about a readvance of sea-water intrusion in many coastal areas, which necessitated restrictions on water use. The effect of drought on the regional water supply, continued population growth and increased water demands, and deterioration of the water quality in many of the canals and waterways of the urban areas accentuated the need for improved water management and land-use planning. As a result of the water crisis, the Governor of Florida called a special conference in September 1971. The conference, attended by foremost scientific and government personnel, proposed creation of an agency that would develop and implement comprehensive land and water-use plans for south Florida that would minimize environmental degradation.

Florida↗
USGS1984

Potential effects of surface coal mining on the hydrology of the Corral Creek area, Hanging Woman Creek coal field, southeastern Montana

The Corral Creek area of the Hanging Woman Creek coal field, 9 miles east of the Decker coal mines near the Tongue River, contains large reserves of Federal coal that have been identified for potential lease sale. A hydrologic study was conducted in the area to describe existing hydrologic systems and to study assess potential impacts of surface coal mining on local water resources. Hydrogeologic data collected indicate that aquifers are coal and sandstone beds within the Tongue River Member of the Fort Union Formation (Paleocene age) and sand and gravel in valley alluvium (Pleistocene and Holocene age). Surface-water resources are limited to a few spring-fed stock ponds in the higher parts of the area and the intermittent flow of Corral Creek near the mouth. Most of the stock ponds in the area become dry by midsummer. Mining of the Anderson coal bed would remove three stock wells and would lower the potentiometric surface within the coal and sandstone aquifers. The alluvial aquifer beneath Corral Creek and South Fork would be removed. Although mining would alter the existing hydrologic systems and remove several shallow wells, alternative ground-water supplies are available that could be developed to replace those lost by mining. (USGS)

Water-Resources Investigations Report↗
USGS2009

Investigation of coastal hydrogeology utilizing geophysical and geochemical tools along the Broward County coast, Florida

Geophysical (CHIRP, boomer, and continuous direct-current resistivity) and geochemical tracer studies (continuous and time-series 222 Radon) were conducted along the Broward County coast from Port Everglades to Hillsboro Inlet, Florida. Simultaneous seismic, direct-current resistivity, and radon surveys in the coastal waters provided information to characterize the geologic framework and identify potential groundwater-discharge sites. Time-series radon at the Nova Southeastern University National Coral Reef Institute (NSU/NCRI) seawall indicated a very strong tidally modulated discharge of ground water with 222 Rn activities ranging from 4 to 10 disintegrations per minute per liter depending on tidal stage. CHIRP seismic data provided very detailed bottom profiles (i.e., bathymetry); however, acoustic penetration was poor and resulted in no observed subsurface geologic structure. Boomer data, on the other hand, showed features that are indicative of karst, antecedent topography (buried reefs), and sand-filled troughs. Continuous resistivity profiling (CRP) data showed slight variability in the subsurface along the coast. Subtle changes in subsurface resistivity between nearshore (higher values) and offshore (lower values) profiles may indicate either a freshening of subsurface water nearshore or a change in sediment porosity or lithology. Further lithologic and hydrologic controls from sediment or rock cores or well data are needed to constrain the variability in CRP data.

Florida↗
USGS1982

Potential effects of surface coal mining on the hydrology of the Cook Creek area, Ashland coal field, southeastern Montana

The Cook Creek area of the Ashland coal field contains large reserves of Federally owned coal that have been identified for potential lease sale. A hydrologic study has been conducted in the potential lease area to describe existing hydrologic systems and to assess potential impacts of surface coal mining on local water resources. Hydrogeologic data collected from wells, springs, and drill holes indicate that shallow aquifers exist within the Tongue River Member of the Fort Union Formation (Paleocene age) and within valley alluvium (Pleistocene and Holocene age). Shallow aquifers within the Tonge River Member include coal beds, clinker, and lenses of sandstone and siltstone. The Knobloch coal bed, a principal shallow aquifer used for livestock watering in the area, averages about 55 feet in thickness and is completely saturated throughout most of its extent. Coarse alluvial deposits are the most productive aquifers and are a major source of stock water in the Cook Creek basin. Surface-water resources are limited to the upstream reach part of Cook Creek, which flows intermittently. The downstream reach part of Cook Creek, plus all other small drainages that originate in the study area, are ephemeral. Mining of the Knoblock and Sawyer coal beds would remove two alluvial springs, one bedrock spring, and two wells, which are all used for watering of livestock. The potentiometric surface within the Knobloch coal aquifer and the alluvial aquifer in the downstream part of the Cook Creek basin would be lowered during mining. Lowered water levels in these aquifers might substantially affect water levels in five wells outside the mine boundary. After mining, the alluvial aquifer downgradient from the mine area might show a long-term degradation in water quality as a result of leaching of soluble salts from overburden materials used to backfill mine pits. Although mining would alter the existing hydrologic systems and remove several springs and shallow wells, alternative ground-water supplies are available that could be developed to replace those lost by mining. (USGS)

Open-File Report↗
USGS2003

Numerical simulation of ground-water flow in La Crosse County, Wisconsin, and into nearby pools of the Mississippi River

This report describes a two-dimensional regional screening model and two associated three-dimensional ground-water flow models that were developed to simulate the ground-water flow systems in La Crosse County, Wisconsin, and Pool 8 of the Mississippi River. Although the geographic extents of the three-dimensional models were slightly different, both were derived from the same geologic interpretation and regional screening model, and their calibrations were performed concurrently. The objectives of the La Crosse County (LCC) model were to assess the effects of recent (1990s) and potential future ground-water withdrawals and to provide a tool suitable to evaluate the effects of proposed water-management programs. The Pool 8 model objectives were to quantify the magnitude and distribution of ground-water flow into the Pool. The Wisconsin Geological and Natural History Survey and the U.S. Geological Survey developed the models cooperatively. The report describes: 1) the conceptual hydrogeologic model; 2) the methods used in simulating flow; 3) model calibration and sensitivity analysis; and 4) model results, such as simulation of predevelopment conditions and location and magnitude of ground-water discharge into Pool 8 of the Mississippi. Three aquifer units underlie the model area: 1) a shallow unconsolidated sand and gravel aquifer; 2) an upper bedrock aquifer, composed of Cambrian and Ordovician sandstone and dolomite; and 3) a lower bedrock aquifer composed of Cambrian sandstone of the Eau Claire Formation and the Mount Simon Formation. A shale layer that is part of the Eau Claire Formation forms a confining unit separating the upper and lower bedrock aquifers. This confining unit is absent in the Black River and parts of the La Crosse and Mississippi River valleys. Precambrian crystalline basement rock forms the lower base of the ground-water flow system. The U.S. Geological Survey ground-water flow model code, MODFLOW, was used to develop the La Crosse County (LCC) and Pool 8 ground-water flow models. Boundary conditions for the MODFLOW model were extracted from an analytic element screening model of the regional flow system surrounding La Crosse County. Model input was obtained from previously published and unpublished geologic and hydrologic data. Pumpages from municipal and high-capacity wells were also simulated. Model calibration included a comparison of modeled and field-measured water levels and field-measured base flows to simulated stream flows. At calibration, most measured water levels compared favorably to model-calculated water levels. Simulated streamflows at two targets were within 3 percent of estimated measured base flows. Mass balance results from the LCC and Pool 8 models indicated that 63 to 74 percent of ground water was from recharge and 19 to 26 percent was from surface-water sources. Ground-water flow out of the model was to rivers and streams (85 to 87 percent) and pumping wells (11 and 13 percent). The model demonstrates the effects of development on ground water in the study area. The maximum simulated water-level decline in the city of La Crosse metropolitan area is 9.3 feet. Simulated stream losses are similar to the amount of ground water pumped by wells. This indicates that ground water withdrawn by La Crosse County wells is water that under predevelopment conditions discharged to streams and lakes. The models provide estimates of the locations and amount of ground-water flow into Pool 8 and the southern portion of Pool 7 of the Mississippi River. Ground-water discharges into all areas of the pools, except along the eastern shore in the vicinity of the city of La Crosse and immediately downgradient from lock and dam 7 and 8. Ground-water flow into the pools is generally greatest around the perimeter with decreasing amounts away from the perimeter. An area of relatively high ground-water discharge extends out towards the center of Pool 7 from the upper reaches of the pool and may

Wisconsin↗
USGS2017

Hydrologic metrics for status-and-trends monitoring in urban and urbanizing watersheds

Local governmental agencies are increasingly undertaking potentially costly “status-and-trends” monitoring to evaluate the effectiveness of stormwater control measures and land-use planning strategies, or to satisfy regulatory requirements. Little guidance is presently available for such efforts, and so we have explored the application, interpretation, and temporal limitations of well-established hydrologic metrics of runoff changes from urbanization, making use of an unusually long-duration, high-quality data set from the Pacific Northwest (USA) with direct applicability to urban and urbanizing watersheds. Three metrics previously identified for their utility in identifying hydrologic conditions with biological importance that respond to watershed urbanization—T Qmean (the fraction of time that flows exceed the mean annual discharge), the Richards-Baker Index (characterizing flashiness relative to the mean discharge), and the annual tally of wet-season day-to-day flow reversals (the total number of days that reverse the prior days’ increasing or decreasing trend)—are all successful in stratifying watersheds across a range of urbanization, as measured by total contributing area of urban development. All metrics respond with statistical significance to multi-decadal trends in urbanization, but none detect trends in watershed-scale urbanization over the course of a single decade. This suggests a minimum period over which dependable trends in hydrologic alteration (or improvement) can be detected with confidence. The metrics also prove less well suited to urbanizing watersheds in a semi-arid climate, with only flow reversals showing a response consistent with prior findings from more humid regions. We also explore the use of stage as a surrogate for discharge in calculating these metrics, recognizing potentially significant agency cost savings in data collection with minimal loss of information. This approach is feasible but cannot be implemented under current data-reporting practices, requiring measurement of water-depth values and preservation of the full precision of the original recorded data. With these caveats, however, hydrologic metrics based on stage should prove as or more useful, at least in the context of status-and-trends monitoring, as those based on subsequent calculations of discharge.

Hydrological Processes↗