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Results for “Water Resource Research”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 1,315 records · Page 73Linked to original sources

USGS1994

Subsidence and carbon fluxes in the Sacramento/San Joaquin Delta, California

The Sacramento/San Joaquin Delta was once tidal marshland and was formed by the confluence of the Sacramento and the San Joaquin Rivers. The delta covers more than 1,000 square miles and is bordered by the major population centers of the San Francisco Bay area, Sacramento, and Stockton (fig. 1). The delta took its current form by the 1930's when drainage of 100 islands and tracts and construction of 2,250 miles of levees were completed. The land surface on the delta islands has progressively subsided below sea level since the early 20th century. The integrity of the levee network is threatened because subsidence increases the differences in water levels maintained by the levees, which can cause levee failure and consequent flooding of the delta islands. Levee failure affects the quality and beneficial use of water in the delta, which is the major source of California's water supply to millions of residents and acres of agricultural land. This Fact Sheet briefly summarizes the research done by the U.S. Geological Survey, in cooperation with the California Department of Water Resources to assess the causes of subsidence, processes that affect subsidence, and carbon fluxes in the delta.

California↗

USGS2010

Simulated impacts of artificial groundwater recharge and discharge of the source area and source volume of an Atlantic Coastal Plain Stream, Delaware, USA

A numerical groundwater-flow model was used to characterize the source area and volume of Phillips Branch, a baseflow-dominated stream incising a highly permeable unconfined aquifer on the low relief Delmarva Peninsula, USA. Particle-tracking analyses indicate that the source area (5.51 km 2 ) is ~20% smaller than the topographically defined watershed (6.85 km 2 ), and recharge entering ~37% of the surface watershed does not discharge to Phillips Branch. Groundwater residence time within the source volume ranges from a few days to almost 100 years, with 95% of the volume "flushing" within 50 years. Artificial discharge from groundwater pumping alters the shape of the source area and reduces baseflow due to the interception of stream flow paths, but has limited impacts on the residence time of groundwater discharged as baseflow. In contrast, artificial recharge from land-based wastewater disposal substantially reduces the source area, lowers the range in residence time due to the elimination of older flow paths to the stream, and leads to increased discharge to adjacent surface-water bodies. This research suggests that, in this and similar hydrogeologic settings, the "watershed" approach to water-resource management may be limited, particularly where anthropogenic stresses alter the transport of soluble contaminants through highly permeable unconfined aquifers.

Delaware↗

USGS2024

The dominance and growth of shallow groundwater resources in continuous permafrost environments

Water is a limited resource in Arctic watersheds with continuous permafrost because freezing conditions in winter and the impermeability of permafrost limit storage and connectivity between surface water and deep groundwater. However, groundwater can still be an important source of surface water in such settings, feeding springs and large aufeis fields that are abundant in cold regions and generating runoff when precipitation is rare. Whether groundwater is sourced from suprapermafrost taliks or deeper regional aquifers will impact water availability as the Arctic continues to warm and thaw. Previous research is ambiguous about the role of deep groundwater, leading to uncertainty regarding Arctic water availability and changing water resources. We analyzed chemistry and residence times of spring, stream, and river waters in the continuous permafrost zone of Alaska, spanning the mountains to the coastal plain. Water chemistry and age tracers show that surface waters are predominately sourced from recent precipitation and have short (<50 y) subsurface residence times. Remote sensing indicates trends in the areal extent of aufeis over the last 37 y, and correlations between aufeis extent and previous year summer temperature. Together, these data indicate that surface waters in continuous permafrost regions may be impacted by short flow paths and shallow suprapermafrost aquifers that are highly sensitive to climatic and hydrologic change over annual timescales. Despite the lack of connection to regional aquifers, continued warming and permafrost thaw may promote deepening of the shallow subsurface aquifers and creation of shallow taliks, providing some resilience to Arctic freshwater ecosystems.

Proceedings of the National Academy of Sciences↗

USGS2022

Maintaining wetland ecosystem services in a changing climate

A changing climate is causing challenges for soil and water management in many parts of the world. Current soil management practices need to be redesigned to effectively address present and future fluctuating climates. Soil Hydrology in a Changing Climate explores how soil management practices impact soil hydrological characteristics, and how we can improve our understanding of soil and water management under changing conditions. Soil hydrology includes water infiltration and soil water storage, which are critical for agricultural plant and animal production. With our future climate predicted to include hotter, drier conditions, increases in evapotranspiration as well as fewer, more intense storms, improved soil management and soil hydrology are critical to ensuring our agriculture production can meet human demand. This comprehensive book is a valuable resource for land managers, soil conservationists, researchers and others who wish to understand how different management practices affect soil and water dynamics and how these practices can be adjusted to enhance agricultural sustainability and environmental quality.

Book chapter↗

USGS1995

U.S. Geological Survey Federal-State Cooperative Water-Resources Program in Nebraska

Federal, State, and local agencies share keen interests in appraising the Nation's water resources and in seeking solutions to waterrelated problems. The U.S. Geological Survey (USGS) Federal-State Cooperative Water-Resources Program was initiated in 1895 to address the diversity in missions and areas of responsibility of various agencies through joint planning and funding of hydrologic data collection, investigations, and research. During the 100-year history of the cooperative program, the USGS has performed many data-collection and investigation activities in cooperation with a variety of State and local agencies to help meet their goals and to carry out the principal mission of the Water Resources Division of the USGS--to further the understanding of water reSources throughout the Nation. The .cooperative program represents almost 50 percent of USGS water-related activities in Nebraska and is a vital component in addressing water issues of local, State, and National interest.

Nebraska↗

USGS1988

Cooperative federal-state liming research on surface waters impacted by acidic deposition

In the eastern and north-central United States, lakes and streams with low acid neutralizing capacity are at risk from acidity. Resource management agencies are interested in developing mitigation strategies that protect or restore fisheries in these waters. Addition of limestone (calcium carbonate) to improve water quality and prevent episodic depressions of pH during precipitation events and spring runoff is one mitigation technique being used. The ecological changes that accompany such treatment of streams and lakes are being investigated in a cooperative program between the U.S. Fish and Wildlife Service and individual states. Streams in Massachusetts, West Virginia and Tennessee, and a lake in Minnesota are included in this 5-yr research program. Intensive monitoring during pre- and post-liming tracks a suite of physical, chemical and biological parameters that influence the re-establishment or maintenance of healthy fisheries. Supporting studies on liming being conducted at Adirondack lakes in New York focus on fisheries management. A model on the influence of liming on light attenuation and thermal stratification is also being developed. Management guidelines are to be generated from the program results.

Massachusetts, Minnesota, Tennessee, West Virginia↗

USGS2011

Natural resource mitigation, adaptation and research needs related to climate change in the Great Basin and Mojave Desert

This report synthesizes the knowledge, opinions, and concerns of many Federal and State land managers, scientists, stakeholders, and partners from a workshop, held at the University of Nevada, Las Vegas, on April 20-22, 2010. Land managers, research scientists, and resource specialists identified common concerns regarding the potential effects of climate change on public lands and natural resources in the Great Basin and Mojave Desert and developed recommendations for mitigation, adaptation, and research needs. Water and, conversely, the effects of drought emerged as a common theme in all breakout sessions on terrestrial and aquatic species at risk, managing across boundaries, monitoring, and ecosystem services. Climate change models for the southwestern deserts predict general warming and drying with increasing precipitation variability year to year. Scientists noted that under these changing conditions the past may no longer be a guide to the future in which managers envision increasing conflicts between human water uses and sustaining ecosystems. Increasing environmental stress also is expected as a consequence of shifting ecosystem boundaries and species distributions, expansion of non-native species, and decoupling of biotic mutualisms, leading to increasingly unstable biologic communities. Managers uniformly expressed a desire to work across management and agency boundaries at a landscape scale but conceded that conflicting agency missions and budgetary constraints often impede collaboration. More and better science is needed to cope with the effects of climate change but, perhaps even more important is the application of science to management issues using the methods of adaptive management based on long-term monitoring to assess the merits of management actions. Access to data is essential for science-based land management. Basic inventories, spatial databases, baseline condition assessments, data quality assurance, and data sharing were identified as top information priorities by all participants at this workshop. Optimizing the utility of ecosystem monitoring data will require standardizing monitoring protocols across agencies. Better communication among researchers and managers and cooperation through partnerships to manage resources across boundaries were emphasized as necessary for adapting to changing climatic conditions. However, even these strategies may be insufficient unless policy mandates, agency missions, and funding are coordinated at a high level.

Scientific Investigations Report↗

USGS1980

Bibliography of geology and hydrology, southwestern New Mexico

The southwestern part of New Mexico is recognized as a source of abundant and varied natural resources. This bibliography of over 2,700 references concerned with geology, hydrology, chemistry, and geography has been compiled to assist physical science researchers in their study and development of this region.

New Mexico↗

USGS2013

Analysis of changes in water-level dynamics at selected sites in the Florida Everglades

The historical modification and regulation of the hydrologic patterns in the Florida Everglades have resulted in changes in the ecosystem of South Florida and the Florida Everglades. Since the 1970s, substantial focus has been given to the restoration of the Everglades ecosystem. The U.S. Geological Survey through its Greater Everglades Priority Ecosystem Science and National Water-Quality Assessment Programs has been providing scientific information to resource managers to assist in the Everglades restoration efforts. The current investigation included development of a simple method to identify and quantify changes in historical hydrologic behavior within the Everglades that could be used by researchers to identify responses of ecological communities to those changes. Such information then could be used by resource managers to develop appropriate water-management practices within the Everglades to promote restoration. The identification of changes in historical hydrologic behavior within the Everglades was accomplished by analyzing historical time-series water-level data from selected gages in the Everglades using (1) break-point analysis of cumulative Z-scores to identify hydrologic changes and (2) cumulative water-level frequency distribution curves to evaluate the magnitude of those changes. This analytical technique was applied to six long-term water-level gages in the Florida Everglades. The break-point analysis for the concurrent period of record (1978–2011) identified 10 common periods of changes in hydrologic behavior at the selected gages. The water-level responses at each gage for the 10 periods displayed similarity in fluctuation patterns, highlighting the interconnectedness of the Florida Everglades hydrologic system. While the patterns were similar, the analysis also showed that larger fluctuations in water levels between periods occurred in Water Conservation Areas 2 and 3 in contrast to those in Water Conservation Area 1 and the Everglades National Park. Results from the analysis indicate that the cumulative Z-score curve, in conjunction with cumulative water-level frequency distribution curves, can be a useful tool in identifying and quantifying changes in historical hydrologic behavior within the Everglades. In addition to the analysis, a spreadsheet application was developed to assist in applying these techniques to time-series water-level data at gages within the Everglades and is included with this report.

Florida↗

USGS2025

Evapotranspiration terminology and definitions

Evapotranspiration (ET), the combined process of evaporation from soil and plant surfaces and transpiration from plant tissue, plays a pivotal role in the global water and energy balance. Accurately quantifying ET at various spatial scales is important for diverse applications, including irrigation and natural resource management. While efforts to standardize ET methodology have progressed over the last few decades, some confusion and disagreements in terminology persist among communities of researchers and practitioners involved in the measurement, estimation, and simulation of ET. This technical note addresses the historical evolution and standardization of ET terminology, aiming to reduce and mitigate disparities in definitions and usage by advocating for standardized definitions and emphasizing the adoption of reference ET ( ET ref ) terminology to promote consistency and accuracy and to avoid ambiguity. This document provides comprehensive definitions of key terms, including crop (i.e., vegetation cover) coefficients, consumptive use (CU), actual crop evapotranspiration ( ET a ), and ET ref variants for short (grass, ET o ) and tall (alfalfa, ET r ) reference crops. Practical discussion on several relevant topics is given: (1) single and dual crop coefficient approaches, (2) applications to nonagricultural vegetation, (3) recommended subscripts for terms, (4) practical guidelines and considerations for ET ref calculation, (5) encouragement to replace “potential ET” terminology with better terms, (6) clarification on maximum ET ( ET max ) and maximum crop coefficient ( K c max ) terms, (7) ET products derived from remote sensing, (8) a brief description of the role of ET in water rights, and (9) a figure illustrating the use of the terms defined herein. The conclusion emphasizes the importance of consistent terminology for effective communication among researchers and end-users, which will facilitate the adoption of standardized ET methods and technologies. This technical note was created by the American Society of Civil Engineers, Environmental and Water Resources Institute (ASCE-EWRI), Evapotranspiration in Irrigation and Hydrology Committee, with input and endorsement from other relevant organizations in the United States and internationally. This note serves as a comprehensive reference guide for ET practitioners and researchers.

Irrigation and Drainage Engineering↗

USGS2003

Hydrologic Resources of Guam

Introduction The U.S. Territory of Guam, which lies in the western Pacific Ocean near latitude 13?28'N and longitude 144?45'E, is the largest (211 mi2) and southernmost of the islands in the Mariana chain. Ground water supplies about 80 percent of the drinking water for the island's 150,000 residents and nearly one million visitors per year. In northern Guam, water is obtained from wells that tap the upper part of a fresh ground-water lens in an aquifer composed mainly of limestone. About 180 wells, nearly all in the north, withdraw about 35 Mgal/d of water with chloride concentrations ranging from 6 to 585 mg/L. In southern Guam, the main source of freshwater is from surface water that runs off the weathered volcanic rocks that are exposed over much of the area. About 9.9 Mgal/d of freshwater is obtained using surface reservoirs. The island's freshwater resources are adequate to meet current (2003) needs, but future demands will eventually be higher. To better understand the hydrology of the island, the U.S. Geological Survey (USGS) entered into a cooperative study with the Water and Environmental Research Institute of the Western Pacific (WERI) at the University of Guam. The objective of the study was to provide a better understanding of the water resources of the island through analysis of data collected by the USGS on Guam. This report provides a description of the general hydrologic principles of the island's ground-water systems, as well as of the rainfall and geology of Guam. Hydrologic data described in the report include water levels, chloride concentrations, and pumpage from ground-water wells and streamflow data from southern Guam.

Water-Resources Investigations Report↗

USGS2010

Groundwater availability study for Guam; goals, approach, products, and schedule of activities

An expected significant population increase on Guam has raised concern about the sustainability of groundwater resources. In response, the U.S. Geological Survey (USGS), in collaboration with the University of Guam's Water and Environmental Research Institute of the Western Pacific (WERI) and with funding from the U.S. Marine Corps (USMC), is conducting a 3.5-year study to advance understanding of regional groundwater dynamics in the Northern Guam Lens Aquifer, provide a new estimate of groundwater recharge, and develop a numerical groundwater flow and transport model for northern Guam. Results of the study, including two USGS reports and a well database, will provide more reliable evaluations of the potential effects of groundwater production and help guide sustainable management of this critical resource.

Fact Sheet↗

USGS2012

Improving scientific communication through the use of U.S. Geological Survey Video Podcasts

It is crucial that scientist find innovative ways of effectively communicating research to resource managers, public officials, and the general public. New technologies, such as video podcasts, are being used as an outreach tool to communicate results from the U.S Geological Survey (USGS) National Water-Quality Assessment (NAWQA) program. The purpose of these podcasts is to summarize scientific research and methods from the NAWQA program. Video podcasts are audio podcasts that incorporate video clips to illustrate ideas presented in simple, concise language with brief 3 to 5-minute films. The process of creating concise podcast messages expands the potential audience for communicating research findings, but the production of video podcasts requires adequate allocation of time and resources. Audience responses to NAWQA podcasts thus far indicate that video is an effective means of sharing scientific information with a broader audience.

Conference Paper↗

USGS2017

Seasonality of stable isotope composition of atmospheric water input at the southern slopes of Mt. Kilimanjaro, Tanzania

To understand the moisture regime at the southern slopes of Mt. Kilimanjaro, we analysed the isotopic variability of oxygen (δ 18 O) and hydrogen (δD) of rainfall, throughfall, and fog from a total of 2,140 samples collected weekly over 2 years at 9 study sites along an elevation transect ranging from 950 to 3,880 m above sea level. Precipitation in the Kilimanjaro tropical rainforests consists of a combination of rainfall, throughfall, and fog. We defined local meteoric water lines for all 3 precipitation types individually and the overall precipitation, δD prec = 7.45 (±0.05) × δ 18 O prec + 13.61 (±0.20), n = 2,140, R 2 = .91, p < .001. We investigated the precipitation-type-specific stable isotope composition and analysed the effects of amount, altitude, and temperature. Aggregated annual mean values revealed isotope composition of rainfall as most depleted and fog water as most enriched in heavy isotopes at the highest elevation research site. We found an altitude effect of δ 18 O rain = −0.11‰ × 100 m −1 , which varied according to precipitation type and season. The relatively weak isotope or altitude gradient may reveal 2 different moisture sources in the research area: (a) local moisture recycling and (b) regional moisture sources. Generally, the seasonality of δ 18 O rain values follows the bimodal rainfall distribution under the influences of south- and north-easterly trade winds. These seasonal patterns of isotopic composition were linked to different regional moisture sources by analysing Hybrid Single Particle Lagrangian Integrated Trajectory backward trajectories. Seasonality of d excess values revealed evidence of enhanced moisture recycling after the onset of the rainy seasons. This comprehensive dataset is essential for further research using stable isotopes as a hydrological tracer of sources of precipitation that contribute to water resources of the Kilimanjaro region.

Mt. Kilimanjaro↗

USGS2008

A national reconnaissance for pharmaceuticals and other organic wastewater contaminants in the United States - II) Untreated drinking water sources

Numerous studies have shown that a variety of manufactured and natural organic compounds such as pharmaceuticals, steroids, surfactants, flame retardants, fragrances, plasticizers and other chemicals often associated with wastewaters have been detected in the vicinity of municipal wastewater discharges and livestock agricultural facilities. To provide new data and insights about the environmental presence of some of these chemicals in untreated sources of drinking water in the United States targeted sites were sampled and analyzed for 100 analytes with sub-parts per billion detection capabilities. The sites included 25 ground- and 49 surface-water sources of drinking water serving populations ranging from one family to over 8 million people. Sixty-three of the 100 targeted chemicals were detected in at least one water sample. Interestingly, in spite of the low detection levels 60% of the 36 pharmaceuticals (including prescription drugs and antibiotics) analyzed were not detected in any water sample. The five most frequently detected chemicals targeted in surface water were: cholesterol (59%, natural sterol), metolachlor (53%, herbicide), cotinine (51%, nicotine metabolite), β-sitosterol (37%, natural plant sterol), and 1,7-dimethylxanthine (27%, caffeine metabolite); and in ground water: tetrachloroethylene (24%, solvent), carbamazepine (20%, pharmaceutical), bisphenol-A (20%, plasticizer), 1,7-dimethylxanthine (16%, caffeine metabolite), and tri (2-chloroethyl) phosphate (12%, fire retardant). A median of 4 compounds were detected per site indicating that the targeted chemicals generally occur in mixtures (commonly near detection levels) in the environment and likely originate from a variety of animal and human uses and waste sources. These data will help prioritize and determine the need, if any, for future occurrence, fate and transport, and health-effects research for subsets of these chemicals and their degradates most likely to be found in water resources used for drinking water in the United States.

Science of the Total Environment↗

USGS2012

Chemical mixtures in untreated water from public-supply wells in the U.S. — Occurrence, composition, and potential toxicity

Chemical mixtures are prevalent in groundwater used for public water supply, but little is known about their potential health effects. As part of a large-scale ambient groundwater study, we evaluated chemical mixtures across multiple chemical classes, and included more chemical contaminants than in previous studies of mixtures in public-supply wells. We (1) assessed the occurrence of chemical mixtures in untreated source-water samples from public-supply wells, (2) determined the composition of the most frequently occurring mixtures, and (3) characterized the potential toxicity of mixtures using a new screening approach. The U.S. Geological Survey collected one untreated water sample from each of 383 public wells distributed across 35 states, and analyzed the samples for as many as 91 chemical contaminants. Concentrations of mixture components were compared to individual human-health benchmarks; the potential toxicity of mixtures was characterized by addition of benchmark-normalized component concentrations. Most samples (84%) contained mixtures of two or more contaminants, each at concentrations greater than one-tenth of individual benchmarks. The chemical mixtures that most frequently occurred and had the greatest potential toxicity primarily were composed of trace elements (including arsenic, strontium, or uranium), radon, or nitrate. Herbicides, disinfection by-products, and solvents were the most common organic contaminants in mixtures. The sum of benchmark-normalized concentrations was greater than 1 for 58% of samples, suggesting that there could be potential for mixtures toxicity in more than half of the public-well samples. Our findings can be used to help set priorities for groundwater monitoring and suggest future research directions for drinking-water treatment studies and for toxicity assessments of chemical mixtures in water resources.

Science of the Total Environment↗

USGS2022

Drought and water management in ancient Maya society

Paleoclimate research in the Maya region of Mesoamerica provides compelling evidence of drought during key periods of cultural transition in Maya society. These include the transition from the Preclassic to the Classic, and from Classic to the Postclassic. Previous research emphasized a causal relationship between drought and cultural change, or so-called “collapse” in the Maya region. Recent advances in the range and precision of climate-sensitive proxies and the development of new archives have enabled quantitative reconstructions of past hydroclimate, as well as providing evidence of high impact, short-duration events, such as tropical cyclones. Simultaneously, archaeological research has unearthed widespread evidence of technologies used by the Maya to exert control over water resources in urban, rural, and agricultural settings. Evidence suggests that many of these water features were in use for multiple generations, possibly centuries, and many were constructed during the Terminal Preclassic and Terminal Classic periods. We suggest that, given the availability of new archaeological and paleoclimate records, these data can be combined to identify the full complexity of Maya adaptation to hydroclimate variability to emphasize adaptation and resilience to both water scarcity and over-abundance (e.g., flooding). Such syntheses, which can offer lessons for present-day efforts to grapple with regional climate change, will benefit from additional studies in data-poor zones of the Maya region, as well as public archiving of paleoclimate and archaeological data.

Progress in Physical Geography: Earth and Environm↗

USGS2022

U.S. Geological Survey Benchmark Glacier Project

The U.S. Geological Survey Benchmark Glacier Project combines decades of direct glaciological data with remote sensing data to advance the quantitative understanding of glacier-climate interactions. The global loss of glaciers, and consequent implications for water resources, sea level rise, and ecosystem function underscores the importance of U.S. Geological Survey glaciology research to facilitate adaptive strategies.

Fact Sheet↗