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USGS1999

Digital Data Set of 14-Digit Hydrologic Units in Indiana

A hydrologic unit is an area of land that can contribute surface-water runoff to a designated outlet point. As part of an initiative to create a nationally uniform hydrologic-unit data base, the U.S. Geological Survey and the Natural Resources Conservation Service, in cooperation with the Indiana Department of Environmental Management and the Indiana Department of Natural Resources Division of Water, created a Geographic Information System digital data set of 14-digit hydrologic units in Indiana. The digital data set consists of arcs and polygons defining hydrologic units in Indiana.

Indiana↗

USGS1993

Distribution of fluoride in ground water of West Virginia

This report describes the results of a study by the U.S. Geological Survey, in cooperation with the West Virginia Geological and Economic Survey, to evaluate the distribution of fluoride in ground water of West Virginia. Fluoride is a natural chemical constituent in domestic and public water supplies in West Virginia. Fluoride concentrations of about 1.0 milligram per liter in drinking water are beneficial to dental health. Concentrations greater than 2.0 milligrams per liter, however, could harm teeth and bones. Fluoride concentra- tions in ground water of West Virginia range from less than 0.1 to 12 milligrams per liter. Fluoride concentrations that exceed 2.0 milligrams per liter are found in wells drilled to all depths, wells drilled in all topographic settings, and wells drilled into most geologic units. Most fluoride concentrations that exceed 2.0 milligrams per liter are located at sites clustered in the northwestern part of the State.

Open-File Report↗

USGS1998

Hydrology of the Bonneville Salt Flats, northwestern Utah, and simulation of ground-water flow and solute transport in the shallow-brine aquifer

This report describes the hydrologic system of the Bonneville Salt Flats with emphasis on the mechanisms of solute transport. Variable-density, three-dimensional computer simulations of the near-surface part of the ground-water system were done to quantify both the transport of salt dissolved in subsurface brine that leaves the salt-crust area and the salt dissolved and precipitated on the land surface. The study was designed to define the hydrology of the brine ground-water system and the natural and anthropogenic processes causing salt loss, and where feasible, to quantify these processes. Specific areas of study include the transport of salt in solution by ground-water flow and the transport of salt in solution by wind-driven ponds and the subsequent salt precipitation on the surface of the playa upon evaporation or seepage into the subsurface. In addition, hydraulic and chemical changes in the hydrologic system since previous studies were documented.

Utah↗

USGS1999

Water resources of the Prairie Island Indian Reservation, Minnesota, 1994-97

This evaluation of the water resources on the Prairie Island Indian Reservation includes data collected from 8 surface-water sites and 22 wells during 1994–97 and historical data. The Mississippi River and the lakes and wetlands connected to it are separated from the Vermillion River and the lakes and wetlands connected to it by the surficial aquifer on Prairie Island and by Lock and Dam Number 3. These surface-water groups form hydrologic boundaries of the surficial aquifer. The aquifer is 130–200 feet thick, extends to bedrock (the Franconia Formation, which is also an aquifer), and is composed primarily of sand and gravel, but also contains thin, isolated lenses of finer-grained material. Flow in the surficial aquifer is normally from the Mississippi River to the Vermillion River (southwest). During spring snowmelt or heavy rains, a ground-water mound forms in the center of the study area and causes radial ground-water flow toward the surrounding surface waters. Surface- and ground-water quality was generally similar, but the median ground-water nitrate concentration was 3.6-times greater than that for surface water. Water samples were dominated by calcium, magnesium, and bicarbonate ions, were usually oxygenated, and had a median dissolved solids concentration of 250 milligrams per liter (mg/L). Thirty-nine percent of groundwater samples showed evidence of anthropogenic nitrate. Most samples contained low concentrations of ammonia (less than 0.04 milligrams per liter as nitrogen). All 15 surface-water samples contained coliform or fecal streptococci bacteria, with 33 percent exceeding 100 colonies per milliliter. Two ground-water and two surface-water samples analyzed for trace metals contained natural concentrations except for one ground-water sample that contained 30 mg/L of lead (probably from a bullet). No volatile organic compounds were detected in 3 ground-water and 3 surface-water samples. Triazine herbicides and their degradation products were detected in one-half of the ground-water samples at concentrations below 1 microgram per liter (µg/L) except for one sample at 3 µg/L. Wells with initially high concentrations of nitrate or triazines continued to have high concentrations throughout the study. Several polycyclic aromatic hydrocarbons and monoaromatic chemicals were detected at low concentration (less than 89 micrograms per kilogram) in 4 samples of 1993 Mississippi River flood sediments deposited in the study area. Ground-water recharge dates based on chlorofluorocarbon (CFC) concentrations indicate that sampled ground water was young (less than 2 decades old) and that all tritium contained in samples from this study can be explained by atmospheric sources. Most historical tritium concentrations can also be explained by atmospheric sources through recharge from spatially and temporally constant precipitation and snowmelt. However, samples from three wells within 800 feet of the Prairie Island Nuclear Power Plant contained tritium at concentrations that cannot be explained by such atmospheric sources. These concentrations decline to that explainable by atmospheric sources within 800 feet of the wells. Many samples contained CFC-113 concentrations higher than that possible from equilibrium with the atmosphere. This CFC-113 contamination is presumably from Mississippi River recharge and complicated the recharge date estimates. The only surface-water constituents exceeding U.S. Environmental Protection Agency drinking water standards was coliform or fecal streptococci bacteria, which was exceeded in all samples. Thirteen percent of ground-water samples exceeded the nitrate maximum contaminant level (MCL), but this is probably higher than the percentage of the aquifer exceeding the nitrate MCL because most of the wells sampled were shallow. Surface-water recharge to and ground-water discharge from the surficial aquifer influence the water quality in both the aquifer and the surrounding surface water. However, surface water probably influences ground-water quality more because of the greater amount of surface water flowing through the study area.

Minnesota↗

USGS2025

Workshop: Nature-based solutions to ecological and economic problems caused by extreme precipitation events in the Upper Mississippi River Basin

Future climate conditions in the Upper Mississippi River Basin are projected to include many more extreme precipitation events. These intense periods of rain can lead to flooding of the Mississippi River itself, as well the small streams and rivers that feed it. This flooding presents a challenge for local communities, farmers, small businesses, river users, and the ecosystems and wildlife in the area. To reduce the damage done by these extreme rainfall events, ‘natural solutions’ are often helpful. This might include preserving forests and grasslands to absorb rainwater before it arrives at streams or restoring wetlands to slow and clean runoff water. For river and natural resource managers to adapt to future climate by using these natural solutions, however, they require accurate information about the projected increase in extreme rainfall events and the effectiveness and costs of a variety of solutions. To provide this information, researchers must understand the decisions that managers are making and the challenges they face. In this project, researchers will host a workshop to facilitate knowledge sharing between natural resource managers, climate modelers, and scientists studying natural solutions. Participants will discuss climate projections related to extreme precipitation events in the region, as well as the management implications and decision-making challenges associated with these events. These conversations will cultivate collaborative relationships between managers and researchers to address critical knowledge gaps and improve future management efforts in the Upper Mississippi River Basin.

Upper Mississippi River basin↗

USGS2008

Simulated natural hydrologic regime of an intermountain playa conservation site

An intermountain playa wetland preserve in Colorado's San Luis Valley was studied to assess how its current hydrologic function compares to its natural hydrologic regime. Current hydrologic conditions were quantified, and on-site effects of off-site water use were assessed. A water-budget model was developed to simulate an unaltered (i.e., natural) hydrologic regime, and simulated natural conditions were compared to observed conditions. From 1998-2002, observed stream inflows accounted for ??? 80% of total annual water inputs. No ground water discharged to the wetland. Evapotranspiration (ET) accounted for ??? 69% of total annual water loss. Simulated natural conditions differed substantially from current altered conditions with respect to depth, variability, and frequency of flooding. During 1998-2002, observed monthly mean surface-water depth was 65% lower than under simulated natural conditions. Observed monthly variability in water depth range from 129% greater (May) to 100% less (September and October) than simulated. As observed, the wetland dried completely (i.e., was ephemeral) in all years; as simulated, the wetland was ephemeral in two of five years. For the period 1915-2002, the simulated wetland was inundated continuously for as long as 16 years and nine months. The large differences in observed and simulated surface-water dynamics resulted from differences between altered and simulated unaltered stream inflows. The maximum and minimum annual total stream inflows observed from 1998-2005 were 3.1 ?? 106 m3 and 0 m3, respectively, versus 15.5 ?? 106 m3 and 3.2 ?? 106 m3 under simulated natural conditions from 1915-2002. The maximum simulated inflow was 484% greater than observed. These data indicate that the current hydrologic regime of this intermountain playa differs significantly from its natural hydrologic regime, which has important implications for planning and assessing conservation success. ?? 2008, The Society of Wetland Scientists.

Wetlands↗

USGS2016

Climate Change Science Activities of the U.S. Geological Survey in New England

The U.S. Geological Survey (USGS) has actively pursued research in the effects of climate change on the hydrology of New England. Ongoing focus areas of climate change science activities of the USGS in New England include the following: • Hydrologic climate-response data (initiating or expanding long-term hydrologic climate-response data collection networks to detect and monitor climate-related changes in hydrology) • Relations between historical climatic and hydrologic variation (investigating historic relations between long-term climatic variation and hydrologic variation and connecting these relations to future conditions as forecasted by the Interagency Panel on Climate Change (Nakićenović and others, 2000) • Hydrologic change on natural and human (incorporating climate change scenarios into assessments of how flows in streams or water levels in aquifers may change) • Relations between climatic and hydrologic variation (characterizing impacts of climate change on floods and droughts, the long-term availability of water supplies for societal and natural uses in response to climate changes) • Developing tools to forecast ecosystem change and water resources management (developing regionally consistent tools for forecasting ecosystem change and resource management) This fact sheet presents recent climate change investigations of the USGS in New England using selected recent publications. These publications highlight the broad spectrum of expertise and commitment to understanding the relations of climate change and water resources in New England.

New England↗

USGS2024

Recent, widespread nitrate decreases may be linked to persistent dissolved organic carbon increases in headwater streams recovering from past acidic deposition

Long-term monitoring of water quality responses to natural and anthropogenic perturbation of watersheds informs policies for managing natural resources. Dissolved organic carbon (DOC) and nitrate (NO 3 − ) in streams draining forested landscapes provide valuable information on ecosystem function due to their biogeochemical reactivity and solubility in water. Here we evaluate a 20-year record (2001−2021) of biweekly stream-water samples ( n > 3000) and continuous discharge in three forested catchments in the Adirondack region of New York to investigate and interpret long-term trends in DOC and NO 3 − concentrations. Results from the intensively monitored catchments were compared with data from synoptic surveys of streams throughout the Adirondack region. A weighted regressions on time, discharge, and season (WRTDS) model, used to estimate daily flow-normalized concentrations, determined that DOC increased by ~30 to 50 % while NO 3 − decreased by ~50 to 70 % over the study period. The large amount of data from catchments with different soil properties permitted us to assess the relative effects of hydrology, season, and land cover factors on temporal trends in DOC and NO 3 − concentrations. We found weak evidence of climatic forcing of long-term increases in DOC, and instead contend that declining ionic strength in precipitation linked to declining anthropogenic acid deposition is driving DOC trends in stream waters. Nitrate concentrations were more variable but clearly decreased in recent years possibly related to declining N deposition. The recent increase in DOC:NO 3 − in all catchments indicates a major shift in stream stoichiometry that reflects changes in ecosystem functioning that may have important biogeochemical implications for terrestrial as well as aquatic ecosystems.

Science of the Total Environment↗

USGS1982

Hydrology of the Beryl-Enterprise area, Escalante Desert, Utah, with emphasis on ground water; With a section on surface water

An investigation of the water resources of the Beryl-Enterprise area, Escalante Desert, Utah (pl. 1), was made during 1976-78 as part of a cooperative program with the Utah Department of Natural Resources, Division of Water Rights. Wells were the most important source of water for all purposes in the Beryl-Enterprise area during 1978, but it has not always been so. For nearly a century after the first settlers arrived in about 1860, streams supplied most of the irrigation water and springs supplied much of the water for domestic and stock use. A few shallow wells were dug by the early settlers for domestic and stock water, but the widespread use of ground water did not start until the 1920's when shallow wells were first dug to supply irrigation water. Ground-water withdrawals from wells, principally for irrigation, have increased nearly every year since the 1920's. The quantity withdrawn from wells surpassed that diverted from surface sources during the mid-1940's and was about eight times that amount during the 1970's. As a result, water levels have declined measurably throughout the area resulting in administrative water-rights problems. The primary purpose of this report is to describe the water resources with emphasis on ground water. The surface-water resources are evaluated only as they pertain to the understanding of the ground-water resources. A secondary purpose is to discuss the extent and effects of the development of ground water in order to provide the hydrologic information needed for the orderly and optimum development of the resource and for the effective administration and adjudication of water rights in the area. The hydrologic data on which this report is based are given in a companion report by Mower (1981).

Utah↗

USGS1970

Ground-water conditions in southern Utah Valley and Goshen Valley, Utah

The investigation of ground-water conditions in southern Utah Valley and Goshen Valley, Utah, was made by the U. S. Geological Survey as part of a cooperative program with the Utah Department of Natural Resources, Division of Water Rights, to investigate the water resources of the State. The purposes of the investigation were to (1) determine the occurrence, recharge, discharge, movement, storage, chemical quality, and availability of ground water; (2) appraise the effects of increased withdrawal of water from wells; and (3) evaluate the effect of the Central Utah Project on the ground-water reservoir and the water supply of Utah Lake. This report presents a description of the aquifer system in the two valleys, a detailed description of the ground-water resources, and conclusions about potential development and its effect on the hydrologic conditions in the valleys. Two supplementary reports are products of the investigation. A basic-data release (Cordova, 1969) contains most of the basic data collected for the investigation, including well characteristics, drillers' logs, water levels, pumpage from wells, chemical analyses of ground and surface waters, and discharge of selected springs, drains, and streams. An interpretive report (Cordova and Mower, 1967) contains the results of a large-scale aquifer test in southern Utah Valley.

Utah↗

USGS2023

An integrated hydrologic model to support the Central Platte Natural Resources District Groundwater Management Plan, central Nebraska

The groundwater and surface-water supply of the Central Platte Natural Resources District supports a large agricultural economy from the High Plains aquifer and Platte River, respectively. This study provided the Central Platte Natural Resources District with an advanced numerical modeling tool to assist with the update of their Groundwater Management Plan. An integrated hydrologic model, called the Central Platte Integrated Hydrologic Model, was constructed using the MODFLOW-One-Water Hydrologic Model code with the Newton solver. This code integrates climate, landscape, surface water, and groundwater-flow processes in a fully coupled approach. Model framework included 163 rows; 327 columns; 2,640 feet cell sides; and 3 vertical layers. A predevelopment model simulated steady-state hydrologic conditions prior to April 30, 1895, and a development period model discretized into 610 stress periods simulated transient hydrologic conditions from May 1, 1895, to December 31, 2016, using 170 biannual stress periods from 1895 to 1980, and monthly stress periods from May 1, 1980, to December 31, 2016. Calibration of the Central Platte Integrated Hydrologic Model involved two phases: a manual adjustment of parameters, followed by the automated calibration completed using BeoPEST that was facilitated by the employment of the singular value decomposition-assist features of PEST that specified 50 super parameters assembled from the 435 adjustable parameters and Tikhonov regularization. The average absolute groundwater-level residuals for model layers one, two, and three were 6.1, 12.4, and 7.4 feet, respectively. Calibrated horizontal hydraulic conductivity was about 70, 32, and 35 feet per day for layers 1, 2, and 3, respectively. The largest development period inflow to groundwater was recharge from deep percolation past the root zone, averaging 1,122,257 acre-feet per year (2.7 inches per year), and the largest outflow was to irrigation wells, averaging 693,171 acre-feet per year (10.2 inches per year for the Central Platte Natural Resources District). Other substantial groundwater outflows included evapotranspiration and base flow. For the total development period, there was a net change in storage of −122,393 acre-feet per year (−0.3 inch per year). The calibrated Central Platte Integrated Hydrologic Model was used to simulate eight different potential future climate and irrigation pumping conditions from January 1, 2017, to December 31, 2049. Simulated future groundwater levels within the Central Platte Natural Resources District varied significantly between scenarios and locally, from 13.8 feet below to 7.6 feet above baseline 1982 groundwater levels. Most areas exhibited groundwater-level declines for the drought scenarios and rises for the alternate irrigation scenarios. Changes in scenario groundwater levels correlated with the relations between farm net recharge and irrigation pumping. Linear “first order second moment” techniques indicated that the uncertainty in projected groundwater altitudes was reduced by 15.33 feet through model calibration.

Nebraska↗

USGS1960

A primer on water

When you open the faucet you expect water to flow. And you expect it to flow night or day, summer or winter, whether you want to fill a glass or water the lawn. It should be clean and pure, without any odor. You have seen or read about places where the water doesn't have these qualities. You may have lived in a city where you were allowed to water the lawn only during a few hours of certain days. We know a large town where the water turns brown after every big rainstorm. Beginning shortly after World War II, large areas in the Southwestern United States had a 10-year drought, and newspapers published a lot of information about its effects. Some people say that the growing demand for water will cause serious shortages over much of the country in the next 10 to 40 years. But it has always been true that while water wells and springs dry up in some places, floods may be occurring in other places at the same time. Nearly every month news stories are published describing floods somewhere in the country. In fact, every year, on the average, 75,000 persons are forced from their homes by floods. In some years, as in 1951 when the lower Kansas River experienced a great flood, half a million people are affected. To understand the reasons for such recurring distress, it is necessary to know something about rivers and about the flat land or flood plain that borders the river. Interest in water and related problems is growing as our population increases and as the use of water becomes steadily greater. To help meet this heightened interest in general information about water and its use and control is the reason this primer was written. The primer is in two parts. The first part tells about hydrology, or the science that concerns the relation of water to our earth, and the second part describes the development of water supplies and the use of water. The Geological Survey is publishing this primer in nontechnical language in the hope that it will enable the general reader to understand the facts about water as a part of nature, and that by having this understanding the people can solve their water problems. We, as representatives of the Geological Survey, acknowledge with thanks the helpful suggestions made on an early draft by Marion Loizeaux, Maria Lord Converse, Constance Foley, Laura R. Langbein, and Bruce C. Leopold. We are also indebted to various geologists and engineers of the Survey for their discerning critical reviews.

General Interest Publication↗

USGS2013

Progress toward establishing a national assessment of water availability and use

The Omnibus Public Land Management Act of 2009 (Public Law 111-11) was passed into law on March 30, 2009. Subtitle F, also known as the SECURE Water Act, calls for the establishment of a "national water availability and use assessment program" within the U.S. Geological Survey (USGS). A major driver for this recommendation was that national water availability and use have not been comprehensively assessed since 1978. This report fulfills a requirement to report to Congress on progress in implementing the national water availability and use assessment program, also referred to as the National Water Census. The SECURE Water Act authorized \$20 million for each of fiscal years (FY) 2009 through 2023 for assessment of national water availability and use. The first appropriation for this effort was \$4 million in FY 2011, followed by an appropriation of \$6 million in FY 2012. The National Water Census synthesizes and reports information at the regional and national scales, with an emphasis on compiling and reporting the information in a way that is useful to states and others responsible for water management and natural-resource issues. The USGS works with Federal and non-Federal agencies, universities, and other organizations to ensure that the information can be aggregated with other types of water-availability and socioeconomic information, such as data on food and energy production. To maximize the utility of the information, the USGS coordinates the design and development of the effort through the Federal Advisory Committee on Water Information. A National Water Census is a complex undertaking, particularly because there are major gaps in the information needed to conduct such an assessment. To maximize progress, the USGS engaged stakeholders in a discussion of priorities and leveraged existing studies and program activities to enhance efforts toward the development of a National Water Census.

Circular↗

USGS2016

Relation between Enterococcus concentrations and turbidity in fresh and saline recreational waters, coastal Horry County, South Carolina, 2003–04

Bacteria related to the intestinal tract of humans and other warm-blooded animals have been detected in fresh and saline surface waters used for recreational purposes in coastal areas of Horry County, South Carolina, since the early 2000s. Specifically, concentrations of the facultative anaerobic organism, Enterococcus , have been observed to exceed the single-sample regulatory limit of 104 colony forming units per 100 milliliters of water. Water bodies characterized by these concentrations are identified on the 303(d) list for impaired water in South Carolina; moreover, because current analytical methods used to monitor Enterococcus concentrations take up to 1 day for results to become available, water-quality advisories are not reflective of the actual health risk. To determine if Enterococcus concentrations in surface water could be assessed in a more rapid manner, an investigation was completed between 2003 and 2004 in the study area of coastal Horry County, South Carolina. The study was designed to assess the relation between Enterococcus concentrations and turbidity, which, unlike Enterococcus concentrations, can be measured continuously by using a multiparameter water-quality sensor and results reported in real time. In 2003, three water-quality data collection stations that included a multiparameter water-quality sensor that measured turbidity were located in three representative surface-water basins in coastal Horry County, South Carolina. All these locations had previous reports of high Enterococcus concentrations. At each station, the water-quality sensor was placed in the water column and continuously measured turbidity, pH, specific conductivity, dissolved oxygen, and temperature. Each water-quality data collection station also monitored instantaneous precipitation and wind speed and direction. Surface-water samples were collected at each station during events characterized by no precipitation and by some recorded precipitation using manual and automatic methods, and analyzed for Enterococcus concentrations. A comparison of Enterococcus concentrations in surface-water samples collected simultaneously using both methods indicated a positive relation, although the average percent relative difference between the methods was 46 percent. During a period of no precipitation in February 2004, no relation between turbidity and Enterococcus concentrations was observed for surface-water samples collected at the water-quality data collection station located in the channel that drains a freshwater swamp. In contrast, during periods of precipitation in March and August 2004 at this location, a positive relation was observed between turbidity and Enterococcus concentrations in surface-water samples; that is, water samples characterized by higher turbidity also contained higher Enterococcus concentrations. At the water-quality data collection station located in a channel that drains to the surf zone of the Atlantic Ocean, no relation was observed between turbidity and Enterococcus concentrations during periods of either no precipitation (July 2004) or precipitation (August 2004). At this location, the turbidity was inversely related to relative tide height, high turbidity was observed during low tide when freshwater flowed seaward, and low turbidity was observed during high tide when saline seawater flowed landward. The positive relation observed between turbidity and Enterococcus concentrations in surface water at the water-quality data collection station located in the channel that drains a freshwater swamp may be attributed to bacterial survival in the abundant channel bed sediments that characterized this more naturalized area. Surface-water bed sediments collected near each water-quality data collection station and the surf zone were incubated in static microcosms in the laboratory and analyzed for Enterococcus concentrations over time. Enterococcus concentrations continued to persist in bed sediments collected in the channel that drains the swamp even after almost 4 months of incubation. Conversely, enterococci were not observed to persist in bed sediments characterized by high specific conductance. Although it is currently (2016) unknown whether this persistence of enterococci demonstrates growth or viability, the data indicate that enterococci can exist in channel bed-sediment environments outside of a host for a long time. This observation confirms previous reports that challenge the use of Enterococcus concentrations as an indicator of the recent introduction of fecal-related material and the associated acute risk to other pathogens.

South Carolina↗

USGS1980

Ground-water data for Georgia, 1979

This report continues a publication format that annually presents both water-level and water-quality data. In this format the information is presented in two-page units: the left page presents a text which summarizes the information for an area or subject and the right page consists of one or more illustrations. Daily mean water-level fluctuations and trends are shown in hydrographs for the previous year and fluctuations of the monthly mean water level for the previous 10 years in selected observation wells in Georgia. The selected wells best illustrate the effects of changes in recharge and discharge in the various ground-water reservoirs in the State A short narrative explains fluctuations and trends in each hydrograph. Monitoring ground-water levels is essential to the understanding of storage changes and other changes in a ground-water reservoir or aquifer. Fluctuations and long-term trends in water levels occur as a result of recharge to and discharge from the reservoir. Varying rates of recharge occur chiefly as a result of varying rates of precipitation, evapotranspiration, and surface-water infiltration into the ground-water reservoir. Discharge occurs as natural flow from the aquifer to streams and springs, direct ground-water evapotranspiration, and as manmade withdrawal from wells. Ground-water levels have been monitored in Georgia for at least a hundred years. Most of the data gathered were used in area 1 reconnaissance studies, and published, usually as tables, with a few graphs of water-level trends. These data had limited value, especially considering the time lag between data collection and publication. With the advent of continuously monitoring recorders and computer processing of data, this information can now be presented to the user in an understandable and timely manner.

Georgia↗

USGS1996

Numerical simulation of solute transport in southwestern Salt Lake Valley, Utah

Contaminated ground water characterized by high concentrations of dissolved solids and dissolved sulfate, and in areas, by low pH and elevated concentrations of metals, is present near public-supply wells in the southwestern Salt Lake Valley. To provide State officials and water users with information concerning the potential movement of contaminated ground water to points of withdrawal in the area, an analysis of solute transport using computer models was done by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, and local municipalities and water users. A three-dimensional solute-transport model was developed and couples with an existing ground-water flow model of Salt Lake Valley to simulate the movement of dissolved sulfate in ground water in southwestern Salt Lake Valley. Development and calibration of the transport model focused mainly on sulfate movement down-gradient from the Bingham Creek Reservoirs and the South Jordan evaporation ponds east of the mouth of Bingham Canyon. Estimates of transport parameters were adjusted during a calibration simulation representing conditions during 1965-93. After calibration, the transport model was used to simulate future sulfate movement for 1994-2043. Because of uncertainty in estimated transport-parameter values, three projection transport simulations incorporating a range of probable parameter values were done to evaluate future sulfate movement and changes in sulfate concentrations at selected public-supply wells. These projection simulations produced a possible range of computed transport rates and patterns. In general, the projection simulations indicated movement of the sulfate plume east of the Bingham Creek reservoir toward public-supply wells northeast of the reservoirs and then eastward toward the Jordan River. Ground water with high concentrations of sulfate east of the South Jordan evaporation ponds is simulated as moving west to east under the Jordan River towards public-supply wells during the final 25 years of the simulation period. An increase in sulfate concentration from 200 mg/l in 2006 to 4,100 mg/l in 2022 was the largest simulated increase at public-supply wells northeast of the reservoirs. An increase in sulfate concentration from 150 mg/l in 2024 to 340 mg/l in 2043 was the largest simulated increase at public-supply wells in the south-central Salt Lake Valley just east of the Jordan River.

Utah↗

USGS2022

Factors influencing the use of water-filled tree cavities by eastern ratsnakes (Pantherophis alleghaniensis)

For some animals, specific microhabitats may be particularly important for certain behaviors and/or age or sex classes. Here we explore the use of previously unrecognized retreat sites (water-filled tree cavities) by Eastern Ratsnakes ( Pantherophis alleghaniensis ). During 4 y of radio telemetry, approximately half of the 45 ratsnakes monitored used water-filled cavities. Typically, water-filled cavities (phytotelmata) were in live Laurel Oaks ( Quercus laurifolia ) and Black Cherry ( Prunus serotina ) where limbs had broken off, internal wood had rotted, and water accumulated. Water-filled cavities were used by ratsnakes at about the same frequency as tree stumps but less frequently than snags, brushpiles, or downed logs. Snakes remained in water-filled cavities for an average of 10 d compared to only 2–4 d in other structures. Reproductive females (both pre- and post-egg laying) were four times more likely to use water-filled cavities than non-gravid or male ratsnakes, suggesting cavities are used to offset water loss associated with gestation. Ratsnakes used water-filled cavities far more in summer than spring even though thermal profiles of cavities were similar to those of other retreat structures, indicating their use was not for thermoregulation. Multiple snakes often used cavities simultaneously, suggesting that cavities are either limited or facilitate social interaction. Snakes did not use artificial water-filled cavities, suggesting that natural sites may provide snakes with some unknown benefit beyond hydration. Water-filled cavities appear to be important for ratsnakes, particularly reproductive females, and warrant further investigation.

South Carolina↗

USGS1985

Interlaboratory comparability, bias, and precision for four laboratories measuring constituents in precipitation, November 1982-August 1983

Four laboratories were evaluated in their analysis of identical natural and simulated precipitation water samples. Interlaboratory comparability was evaluated using analysis of variance coupled with Duncan 's multiple range test, and linear-regression models describing the relations between individual laboratory analytical results for natural precipitation samples. Results of the statistical analyses indicate that certain pairs of laboratories produce different results when analyzing identical samples. Analyte bias for each laboratory was examined using analysis of variance coupled with Duncan 's multiple range test on data produced by the laboratories from the analysis of identical simulated precipitation samples. Bias for a given analyte produced by a single laboratory has been indicated when the laboratory mean for that analyte is shown to be significantly different from the mean for the most-probable analyte concentrations in the simulated precipitation samples. Ion-chromatographic methods for the determination of chloride, nitrate, and sulfate have been compared with the colorimetric methods that were also in use during the study period. Comparisons were made using analysis of variance coupled with Duncan 's multiple range test for means produced by the two methods. Analyte precision for each laboratory has been estimated by calculating a pooled variance for each analyte. Analyte estimated precisions have been compared using F-tests and differences in analyte precisions for laboratory pairs have been reported. (USGS)

Water-Resources Investigations Report↗