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USGS1996

Influences of environmental settings on aquatic ecosystems in the Apalachicola-Chattahoochee-Flint River basin

The watershed boundary of the Apalachicola-Chattahoochee-Flint (ACF) River basin defines an aquatic ecosystem whose water quality is the result of complex interactions of natural and human influences on land and water resources. Topics relating to the basin's environmental setting-its physical, biological, and cultural characteristics-are summarized to provide an understanding of factors that influence water quality and the health of aquatic ecosystems. The ACF River basin lies partly in southwestern Georgia, southeastern Alabama, and northwestern Florida and covers 19,800 square miles in the Blue Ridge, the Piedmont, and the Coastal Plain Provinces. The basin includes the drainages of the Chattahoochee River and the Flint River, which meet to form the Apalachicola River. The Apalachicola River flows into the Gulf of Mexico at Apalachicola Bay. Basin hydrology and water quality are influenced by 16 mainstem reservoirs, 13 of which are on the Chattahoochee River. Ground water in the basin is contained in six aquifers-the surficial aquifer system, the Floridan aquifer system, the Claiborne aquifer, the Clayton aquifer, the Providence aquifer, and the crystalline-rock aquifer. Physiography, climate, and hydrology of the ACF River basin provide natural conditions that support a rich and abundant diversity of plants and animals. Although most of the ACF River basin has been altered by human activities, the basin's environment is noteworthy for its remaining biological diversity and the role it plays in sustaining biological productivity in Apalachicola Bay. The Bay produces 90 percent of Florida's and 13 percent of the Nation's oyster harvest; and functions as a nursery for penaeid shrimp, blue crabs, and a variety of fin fish. The diversity of the basin's aquatic fauna is noteworthy because the basin is home to (1) the largest number of fish species among Gulf Coast drainages east of the Mississippi River, (2) the largest assemblage of freshwater fish in Florida, (3) the largest number of mollusc species among western Florida drainages, and (4) the highest species density of amphibians and reptiles on the continent north of Mexico. Population of the ACF River basin in 1990 was estimated at 2.6 million. Nearly 90 percent of the total population lived in Georgia, and nearly 60 percent lived in the Metropolitan Atlanta area. The 1990 basin population is projected to increase by 15 percent to 3.0 million by the year 2000, and by 30 percent to 3.4 million by 2010. The largest increases in populations are projected for the Metropolitan Atlanta area. In 1972-76, approximately 59 percent of the basin was covered by forest, 29 percent was agricultural, 5 percent was wetland, 4 percent was urban, and 3 percent was water or barren land. Most of the original land cover of the basin has been transformed by human activity. Timber is the basin's largest cash crop and most forests consist of second-growth stands or large acreages of planted pine. The dominant agricultural land use in the Piedmont Province is pasture and confined feeding for dairy, livestock, and poultry production. Row-crop agriculture, orchards, and silviculture are most common in the Coastal Plain Province. The top five crops in order from most to least acres harvested in 1990 were peanuts, corn, soybeans, wheat, and cotton. The water in the basin is used for public and industrial supply, irrigation, power generation, navigation, and recreation. Although most public-supply withdrawals in the Blue Ridge and Piedmont Provinces are from surface-water sources, with the exception of counties near or immediately below the Fall Line, all publicly supplied water in the Coastal Plain is withdrawn from ground-water sources. Ground water supplied 18 percent of the basin's population served by public supply. Total water withdrawn in the ACF River basin in 1990 was 2,098 million gallons per day (Mgal/d), of which Georgia withdrew 82 percent and Florida and Alabama each withdrew 9 percent. Power generation is the single largest water use. Sixteen of the basin's 22 power generating plants are located along the mainstem of the Chattahoochee River. The U.S. Army Corps of Engineers maintains a navigation channel from the mouth of the Apalachicola River to Columbus, Ga., on the Chattahoochee River and to Bainbridge, Ga., on the Flint River. Water quality in the basin is influenced by the operation of 137 municipal wastewater-treatment facilities. In 1990, 354 Mgal/d of municipal wastewater was discharged within the ACF River basin. Eighty-eight percent of the wastewater was discharged into the Chattahoochee River basin, 10.6 percent into the Flint River basin, and 1.4 percent into the Apalachicola River basin. Two-thirds of the 938 stream miles in the Georgia portion of the ACF River basin having water quality that does not meet or only partially meets the designated-use criteria in the Chattahoochee River basin. The Chattahoochee River is the most heavily-used water resource both in the ACF River basin and in Georgia. Urban runoff or unknown nonpoint sources are cited as the causes of water-quality regulations in 72 percent of violations. The remaining causes primarily are combined sewer overflows in the Atlanta area, and discharges from municipal or industrial treatment facilities with inadequate treatment capabilities or operational deficiencies.

Alabama, Florida, Georgia↗

USGS2025

Science needs for determining the effects of climate change on harmful algal blooms in the southeastern United States

The Southeastern United States has many lakes, streams, and reservoirs that serve as important drinking water sources with recreational, agricultural, and ecological uses. However, harmful algal blooms (HABs) are becoming more common in these waters, causing health issues for humans and animals. HABs have been listed as a contaminant of emerging concern, and the magnitude, frequency, and duration of HABs appear to be increasing at the global scale. While it is well known that nutrients stimulate algae growth, it is not clear how climate change and other parameters stimulate the development of toxin production by HABs. The scientific literature describes parameters, such as storm occurrence, temperature, dissolved metals, erosion of soils, increasing length of growing season, discharge, and hydroperiod, that may affect algae growth and toxin production. Climate and hydrologic models address many of the physical and environmental parameters that influence HABs, but no climate models directly address HABs. This report compiles information from the existing literature pertaining to HABs and the modeling and forecasting of HABS. This compilation is done through the incorporation of climate change models. HAB research that involves climate change will require multiple disciplines that bring together ecologists, hydrologists, climatologists, engineers, economists, and new technology. Resource managers could use geographic data about the occurrence and distribution of HABs to develop models that identify waterbodies more vulnerable to HAB events. Development of such models will require teams capable of integrating biological, chemical, and physical factors. Model development will require additional research that can resolve anthropogenic and climate-related environmental factors to identify trends in freshwater HABs. The complexity and interconnectedness of the parameters that influence HAB occurrences will make model development challenging and require rigorous regional calibration.

Open-File Report↗

USGS1980

Annual summary of ground-water conditions in Arizona, spring 1978 to spring 1979

In 1978 the withdrawal of ground water was about 4.2 million acre-feet in Arizona, and slightly more than 3.4 million acre-feet of ground water was used for the irrigation of crops. The amount of ground water withdrawn in 1978 decreased more than 1.2 million acre-feet from the amount withdrawn in 1977 and is the smallest amount withdrawn since the mid-1950 's except in 1966. Nearly all the decrease was in the amount of ground water used for irrigation in the Basin and Range lowlands province. Possible causes for the decrease include above-average precipitation, greater availability of surface water, and some comparatively new conservation practices. The Salt River Valley and the lower Santa Cruz area are the largest agricultural areas in the State; the amount of ground water withdrawn for agricultural use in the Salt River Valley and the lower Santa Cruz area decreased nearly 613,000 and 291,000 acre-feet, respectively, between 1977 and 1978. The report contains two small-scale maps of Arizona that show (1) pumpage of ground water by areas and (2) the status of the ground-water inventory in the State. The main map, which is at a scale of 1:500,000, shows potential well production, depth to water in selected wells in spring 1979, and change in water level in selected wells from 1974 to 1979. The brief text that accompanies the maps summarizes the current ground-water conditions in the State. (USGS)

Open-File Report↗

USGS1981

Surficial geologic map of the eastern Snake River Plain and adjacent areas, 111° -115° W., Idaho and Wyoming

This map portrays the distribution of surficial materials that cover most of the landscape of the eastern Snake River Plain and adjoining areas in a larger part of southeastern Idaho and a very small area in western Wyoming (fig. 1). Almost 350,000 people or 40 percent of Idaho's (estimating 1979 population from Rand McNally (1979)) live in the area, which constitutes about 30 percent of Idaho's land area. The great majority of this population resides in the major irrigated agricultural areas along the Snake River between American Falls and Ashton and between Bliss and Lake Walcott, which contain the important and growing commercial centers of Rexberg, Idaho Falls, Blackfoot, Pocatello, Burley-Rupert, Twin Falls, and Jerome. These areas encompass almost two-thirds of Idaho's irrigated croplands, and, along with water, are the region's most important resource. Major products include potatoes, sugar beets, alfalfa, small grains, and other crops. Along the margins of the Plain and in adjacent basins, smaller areas of irrigated farming and population are present, such as Teton Basin, Mud Lake area, Big and Little Lost River Valleys, Big and Little Wood River Valleys, and Raft River Valley. In several of these basins and in nearby upland areas, dry farming of grains is important. Some of these lands are now being converted to irrigated croplands. Grazing is the dominant economic use of grasslands on the Plain in adjacent basins and uplands. At present, industry assumes a minor role in the region's economy, although food processing and nuclear research at the Idaho National Engineering Laboratory (INEL) locally or important.

Idaho, Wyoming↗

USGS2020

Evaluation of restoration alternatives using hydraulic models of lake outflow at Wapato Lake National Wildlife Refuge, northwestern Oregon

Wapato Lake National Wildlife Refuge near the city of Gaston in northwestern Oregon was established in 2013, and planning is underway to restore a more natural lake and wetland system after more than 100 years of agricultural activity on the lakebed. Several water-management and restoration alternatives are under consideration, one of which involves opening and reconnecting Wapato Lake’s outlet to allow flow in and out of the lake to Wapato Creek and downstream to the Tualatin River. The effects of this and other alternatives are being evaluated, partly through a detailed examination of the lake’s water budget. The water budget for the lake during 2011–13 was quantified by the U.S. Geological Survey in partnership with U.S. Fish and Wildlife Service and others. Results were incorporated in a spreadsheet-based Water Management Scenario Tool (WMST) for Wapato Lake, which predicts the effects of various management actions on daily lake level and potential habitat areas for waterfowl or other target species. Incorporating the effects of a hypothetical open outlet between the lake and the downstream river network in the WMST was accomplished by using a hydraulic model to simulate the flow-exchange rate between Wapato Lake and Wapato Creek over a wide range of lake levels and downstream river conditions. A Hydraulic Engineering Center-River Analysis System (HEC-RAS) one-dimensional unsteady flow model was constructed and calibrated for Wapato Creek and part of the Tualatin River using data from October 2011 to April 2013, and then was used to simulate daily lake/creek exchange flows in water years 1992–2014 under hypothetically constant lake levels. Results were used to populate a table of lake/creek flow-exchange rates for use in the WMST; a dynamic link between the WMST and HEC-RAS was unrealistic because it would require hundreds of calls to HEC-RAS and result in long run times for a single water-year’s WMST calculations with daily time steps. Predictions of daily outlet flows from the WMST were checked against HEC-RAS simulated flows under daily varying lake levels to ensure that the timing and magnitude of lake/creek exchange flows used by the WMST were consistent with those of the hydraulic model. Two scenarios were tested with a hypothetical open lake outlet to show how the WMST could be used to inform restoration planning—one scenario used a year-round open lake outlet, and the other scenario closed that outlet for part of the high-water winter season. Results showed that flows in and out of a year-round open lake outlet would dominate the lake’s water budget and produce water depths during winter and through mid-summer that might be too deep to support waterbird species that require shallow water. Closing the lake outlet during large winter storms and high-water conditions in the downstream river network would isolate the lake from surrounding rivers, keep the lake level lower, and retain substantially more shallow-water areas. Because of the ease with which management alternatives can be evaluated, a water-budget spreadsheet tool such as the WMST has been a valuable part of an analysis of potential water-management and restoration alternatives for Wapato Lake National Wildlife Refuge.

Oregon↗

USGS1937

Ground water in Creek County, Oklahoma

Creek County has been designated as a problem area by the Land Use Planning Section of the Resettlement Administration. Some of the earliest oil fields to brought into production were situated in and near this county, and new fields have been opened from time to time during the ensuing years. The production of the newer fields, however, has not kept pace with the exhaustion of the older fields, and the county now presents an excellent picture of the problems involved in adjusting a population to lands that are nearly depleted of their mineral wealth. Values of land have been greatly depressed; tax collection is far in arrears; tenancy is widespread; and in addition more people will apparently be forced to depend on the income from agriculture than the land seems capable of supporting. The county as a whole is at best indifferently suitable for general farming. The Land Use planning Section proposes to study the present and seemingly immanent maladjustments of population to the resources of the land, and make recommendations for their correction. The writer was detailed to the Land Use Planning Section of Region VIII for the purposes of making studies of ground water problems in the region. In Creek County two investigations were made. In September, 1936, the writer spent about ten days investigating the availability of ground water for the irrigation of garden crops during drouths. If it proved feasible to do this generally throughout the county, the Land Use Planning Section might be able to encourage this practice. The second investigation made by the writer was in regard to the extent to which ground water supplies have been damaged by oil well brines. He was in county for four days late in January 1937, and again in March, 1937. During part of the second field trip he was accompanied by R.M. Dixon, sanitary engineer of the Water Utilization Unit of the Resettlement Administration. (available as photostat copy only)

Open-File Report↗

USGS2012

Assessing future risks to agricultural productivity, water resources and food security: How can remote sensing help?

Although global food production has been rising, the world sti ll faces a major food security challenge. Over one billion people are currently undernourished (Wheeler and Kay, 2010). By the 2050s, the human population is projected to grow to 9.1 billion. Over three-quarters of these people will be living in developing countries, in regions that already lack the capacity to feed their populations . Under current agricultural practices, the increased demand for food would require in excess of one billion hectares of new cropland, nearly equivalent to the land area of the United States, and would lead to significant increases in greenhouse gases (Tillman et al. , 2011). Since climate is the primary determinant of agricultural productivity, changes to it will influence not only crop yields, but also hydrologic balances and supplies of inputs to managed farming systems, and may lead to a shift in the geographic location of some crops . Therefore, not only must crop productivity (yield per unit of land; kg/m 2 ) increase, but water productivity (yield per unit of water or "crop per drop"; kg/m 3 ) must increase as well in order to feed a burgeoning population against a backdrop of changing dietary consumption patterns, a changing climate and the growing scarcity of water and land (Beddington, 2010). The impact from these changes wi ll affect the viability of both dryland subsistence and irrigated commodity food production (Knox, et al. , 2010a). Since climate is a primary determinant of agricultural productivity, any changes will influence not only crop yields, but also the hydrologic balances, and supplies of inputs to managed farming systems as well as potentially shifting the geographic location for specific crops . Unless concerted and collective action is taken, society risks worldwide food shortages, scarcity of water resources and insufficient energy. This has the potential to unleash public unrest, cross-border conflicts and migration as people flee the worst-affected regions to seck refuge in "safe havens", a situation that Beddington described as the "perfect storm" (2010).

Photogrammetric Engineering and Remote Sensing↗

USGS2005

Inventory of ground-water resources in the Kabul Basin, Afghanistan

In 2004, the U.S. Geological Survey began working with engineers at the Afghanistan Geological Survey to provide hydrologic training and equipment and to apply these tools to build an inventory of water wells in the Kabul Basin of Afghanistan. An inventory of 148 wells now includes information on well location, depth, and access. Water-level and water-quality measurements have been made at most of these wells. A water-level elevation map has been constructed, and general directions of ground-water flow have been defined. Ground-water flow in the Kabul Basin is primarily through saturated alluvium and other basin-fill sediments. The water-table surface generally mirrors topography, and ground water generally flows in the directions of surface-water discharge. The quality of ground water in the Kabul Basin varies widely. In some areas, ground-water quality is excellent, with low concentrations of dissolved solids and no problematic constituents. In other areas, however, high concentrations of dissolved solids and the presence of some constituents at concentrations deemed harmful to humans and crops render untreated ground water marginal or unsuitable for public supply and/or agricultural use. Of particular concern are elevated concentrations of nitrate, boron, and dissolved solids, and an indication of fecal pollution in some parts of the basin. As Afghanistan emerges from years of conflict, as institutional capacities rejuvenate and grow, and as the need for wise water-management decisions continues, adequate data and a fuller understanding of the ground-water resource in the Kabul Basin will be imperative. The work described in this report represents only a modest beginning in what will be a long-term data-collection and interpretive effort.

Scientific Investigations Report↗

USGS1994

Analysis of data on nutrients and organic compounds in ground water in the upper Snake River basin, Idaho and western Wyoming, 1980-91

Nutrient and organic compound data from the U.S. Geological Survey and the U.S. Environmental Protection Agency STORET data bases provided information for development of a preliminary conceptual model of spatial and temporal ground-water quality in the upper Snake River Basin. Nitrite plus nitrate (as nitrogen; hereafter referred to as nitrate) concentrations exceeded the Federal drinking-water regulation of 10 milligrams per liter in three areas in Idaho" the Idaho National Engineering Laboratory, the area north of Pocatello (Fort Hall area), and the area surrounding Burley. Water from many wells in the Twin Falls area also contained elevated (greater than two milligrams per liter) nitrate concentrations. Water from domestic wells contained the highest median nitrate concentrations; water from industrial and public supply wells contained the lowest. Nitrate concentrations decreased with increasing well depth, increasing depth to water (unsaturated thickness), and increasing depth below water table (saturated thickness). Kjeldahl nitrogen concentrations decreased with increasing well depth and depth below water table. The relation between kjeldahl nitrogen concentrations and depth to water was poor. Nitrate and total phosphorus concentrations in water from wells were correlated among three hydrogeomorphic regions in the upper Snake River Basin, Concentrations of nitrate were statistically higher in the eastern Snake River Plain and local aquifers than in the tributary valleys. There was no statistical difference in total phosphorus concentrations among the three hydrogeomorphic regions. Nitrate and total phosphorus concentrations were correlated with land-use classifications developed using the Geographic Information Retrieval and Analysis System. Concentrations of nitrate were statistically higher in area of agricultural land than in areas of rangeland. There was no statistical difference in concentrations between rangeland and urban land and between urban land and agricultural land. There was no statistical difference in total phosphorus concentrations among any of the land-use classifications. Nitrate and total phosphorus concentrations also were correlated with land-use classifications developed by the Idaho Department of Water Resources for the Idaho part of the upper Snake River Basin. Nitrate concentrations were statistically higher in areas of irrigated agriculture than in areas of dryland agriculture and rangeland. There was no statistical difference in total phosphorus concentrations among any of the Idaho Department of Water Resources land-use classifications. Data were sufficient to assess long-term trends of nitrate concentrations in water from only eight wells: four wells north of Burley and four wells northwest of Pocatello. The trend in nitrate concentrations in water from all wells in upward. The following organic compounds were detected in ground water in the upper Snake River Basin: cyanazine, 2,4-D DDT, dacthal, diazinon, dichloropropane, dieldrin, malathion, and metribuzin. Of 211 wells sampled for organic compounds, water from 17 contained detectable concentrations.

Idaho;Montana;Nevada;Utah;Wyoming↗

USGS2013

The benefits of improved national elevation data

This article describes how the National Enhanced Elevation Assessment (NEEA) has identified substantial benefits that could come about if improved elevation data were publicly available for current and emerging applications and business uses such as renewable energy, precision agriculture, and intelligent vehicle navigation and safety. In order to support these diverse needs, new national elevation data with higher resolution and accuracy are needed. The 3D Elevation Program (3DEP) initiative was developed to meet the majority of these needs and it is expected that 3DEP will result in new, unimagined information services that would result in job growth and the transformation of the geospatial community. Private-sector data collection companies are continuously evolving sensors and positioning technologies that are needed to collect improved elevation data. An initiative of this scope might also provide an opportunity for companies to improve their capabilities and produce even higher data quality and consistency at a pace that might not have otherwise occurred.

Photogrammetric Engineering and Remote Sensing↗

USGS2026

Comparing DESIS hyperspectral and Landsat 10 simulated superspectral data for crop type classification in California's Central Valley

To advance crop type mapping in support of global food and water security, this study compared three spectral configurations: (A) the full 60-band DLR Earth Sensing Imaging Spectrometer (DESIS) hyperspectral narrowband (HNB) dataset, (B) a 14-band subset of DESIS-derived HNBs aligned with the planned Landsat 10 (formerly Landsat Next) spectral configuration (400–1000 nm), and (C) DESIS-based simulations of Landsat 10 superspectral broadbands. The analysis was conducted in California’s Central Valley, hereafter referred to as “the Central Valley”, during the peak growing month of August. DESIS imagery from August 2021, 2022, and 2023 was used sequentially for model development, testing, and independent validation. Over these three years, DESIS provided extensive hyperspectral coverage of much of the 4 million hectares in the Central Valley’s. Analyses were performed on Google Earth Engine using two pixel-based supervised classifiers, Random Forest (RF) and Support Vector Machine (SVM), to differentiate three major crop classes: row crops, grapes and tree crops, and winter wheat/fallow/other. The highest overall accuracy (86%) was achieved using SVM in combination with either the full DESIS hyperspectral dataset or the 14 DESIS narrowbands corresponding to Landsat 10. This finding aligns with earlier studies showing a small number of strategically positioned narrowbands can be optimal for crop type classification. Use of the narrowband datasets resulted in substantially higher accuracy (overall accuracy of 86%) compared to the simulated Landsat 10 broadbands (overall accuracy of 75%), supporting previous studies highlighting the utility of narrowbands. Despite the high accuracy using August imagery, the study indicates more granular crop type classification will require multi-temporal observations spanning the full phenological cycle (June–October), especially for a large number of crop classes. Acquiring task-based hyperspectral imagery over such large areas throughout the growing season remains operationally challenging. In contrast, Landsat 10 superspectral imagery could provide routine coverage across seasons and years that is practical and scalable for future large area crop type mapping and agricultural monitoring.

California↗

USGS2003

Ground-water use, locations of production wells, and areas irrigated using ground water in 1998, middle Humboldt River basin, north-central Nevada

In 1998, ground water was being pumped from about 420 production wells in the middle Humboldt River Basin for a variety of uses. Principal uses were for agriculture, industry, mining, municipal, and power plant purposes. This report presents a compilation of the number and types of production wells, areas irrigated by ground water, and ground-water use in 14 hydrographic areas of the middle Humboldt River Basin in 1998. Annual pumping records for production wells usually are reported to the Nevada Division of Water Resources. However, operators of irrigation wells are not consistently required to report annual pumpage. Daily power-consumption and pump-discharge rates measured at 20 wells during the 1998 irrigation season and total power use at each well were used to estimate the amount of water, in feet of depth, applied to 20 alfalfa fields. These fields include about 10 percent of the total area, 36,700 acres, irrigated with ground water in the middle Humboldt River Basin. In 1998 an average of 2.0 feet of water was applied to 14 fields irrigated using center-pivot sprinkler systems, and an average of 2.6 feet of water was applied to 6 fields irrigated using wheel-line sprinkler systems. A similar approach was used to estimate the amount of water pumped at three wells using pumps powered by diesel engines. The two fields served by these three wells received 3.9 feet of water by flood irrigation during the 1998 irrigation season. The amount of water applied to the fields irrigated by center-pivot and wheel-line irrigation systems during the 1998 irrigation season was less than what would have been applied during a typical irrigation season because late winter and spring precipitation exceeded long-term monthly averages by as much as four times. As a result, the health of crops was affected by over-saturated soils, and most irrigation wells were only used sporadically in the first part of the irrigation season. Power consumption at 19 of the 20 wells in the 1994-97 irrigation seasons was 110 to 235 percent of the power consumption in the 1998 irrigation season. If the amount of water applied to fields during the 1998 irrigation season were adjusted to account for these differences in power consumption, the average amount of water applied to a field during a typical season using center-pivot and wheel-line sprinkler systems would be 3.1 feet and 3.7 feet, respectively. Total ground water pumped in the middle Humboldt River Basin during 1998 was about 298,000 acre-feet. This pumpage was distributed as follows: 78 percent for mining, 19 percent for irrigation, and 3 percent for industrial, municipal, and power plants combined. Mining pumpage is by far the largest source of ground-water use because several large gold mines have extended below local ground-water levels and the area around each mine must be dewatered in order to maintain a dry and workable mine. Total mining pumpage in 1998 was 233,000 acre-feet, of this total, 23,600 acre-feet was for consumptive use and 209,000 acre-feet was for dewatering eight mines. Excess water from the mines being dewatered was distributed as follows: 74,500 acre-feet was returned to aquifers by infiltration; 33,100 acre-feet was used for irrigation and for consumptive use at two mines and a power plant; 96,700 acre-feet was released to the Humboldt River or one of its tributaries; and 5,260 acre-feet was lost to evaporation.

Water-Resources Investigations Report↗

USGS1995

United States Geological Survey, programs in Nevada

The U.S. Geological Survey (USGS) has been collecting and interpreting natural-resources data in Nevada for more than 100 years. This long-term commitment enables planners to manage better the resources of a State noted for paradoxes. Although Nevada is one of the most sparsely populated States in the Nation, it has the fastest growing population (fig. 1). Although 90 percent of the land is rural, it is the fourth most urban State. Nevada is the most arid State and relies heavily on water resources. Historically, mining and agriculture have formed the basis of the economy; now tourism and urban development also have become important. The USGS works with more than 40 local, State, and other Federal agencies in Nevada to provide natural-resources information for immediate and long-term decisions. Subjects included in this fact sheet: Low-Level Radioactive-Waste Disposal Mining and Water in the Humboldt Basin Aquifer Systems in the Great Basin Water Allocation in Truckee and Carson Basins National Water-Quality Assessment Program Minerals Assessment for Land Management Irrigation Drainage Ground-Water Movement at Nevada Test Site Oil and Gas Resources National Mapping Program Digital Mapping and Aerial Photography Collection of Hydrologlc Data Geologic Mapping Earthquake Hazards Assessing Mineral Resources of the Subsurface Earth Observation Data Cooperative Programs

Nevada↗

USGS2023

An inconvenient trend: Decadal decline in ground height of swamps in Southern Illinois

An understanding of the long-term trends of ground height and sedimentation in a landscape context can provide a framework to better understand the impacts of agricultural development on floodplain processes. This study examined long-term changes in ground height using surface elevation tables (SETs) and sediment deposition measurements in the Cache River floodplains of Southern Illinois including Taxodium distichum swamps in Crawford Tract and Eagle Pond from 2019 to 2022 and in Deer Pond and Snake Hole from 2005 to 2022. The mean ground heights of these swamps decreased by a mean of −0.33, −033, −0.28 and −0.19 cm year −1 , respectively. Annual sediment deposition on feldspar markers in Crawford Tract was negligible from 2020 to 2022 (range of annual deposition depth: <0.1 to 0.4 cm). However, sediment deposition at Deer Pond and Snake Hole was higher from 2006 to 2021 (range of annual deposition depth: <0.1–2.5 and <1 to 2.0 cm, respectively). In some years, the sites appeared scoured, and the feldspar markers had disappeared. The loss of ground height in these swamps could be related to erosion, increased precipitation and/or downcutting of the channel following the construction of a major diversion to dewater the floodplain via the Post Creek Cutoff in the early 1900s. Despite the limitations of this study toward revealing specific mechanisms linking floodplain erosion to channel downcutting and the engineered features of this landscape, this study clearly showed that Cache floodplains have lost height in past decades with potential consequences for the conservation of natural forests.

Illinois↗

USGS2021

The presence of denitrifiers in bacterial communities of urban stormwater best management practices (BMPs)

Stormwater best management practices (BMPs) are engineered structures that attempt to mitigate the impacts of stormwater, which can include nitrogen inputs from the surrounding drainage area. The goal of this study was to assess bacterial community composition in different types of stormwater BMP soils to establish whether a particular BMP type harbors more denitrification potential. Soil sampling took place over the summer of 2015 following precipitation events. Soils were sampled from four bioretention facilities, four dry ponds, four surface sand filters, and one dry swale. 16S rRNA gene analysis of extracted DNA and RNA amplicons indicated high bacterial diversity in the soils of all BMP types sampled. An abundance of denitrifiers was also indicated in the extracted DNA using presence/absence of nirS, nirK , and nosZ denitrification genes. BMP soil bacterial communities were impacted by the surrounding soil physiochemistry. Based on the identification of a metabolically-active community of denitrifiers, this study has indicated that denitrification could potentially occur under appropriate conditions in all types of BMP sampled, including surface sand filters that are often viewed as providing low potential for denitrification. The carbon content of incoming stormwater could be providing bacterial communities with denitrification conditions. The findings of this study are especially relevant for land managers in watersheds with legacy nitrogen from former agricultural land use.

Maryland↗

USGS2001

Selected findings and current perspectives on urban and agricultural water quality by the National Water-Quality Assessment Program

Studies by the USGS National Water-Quality Assessment (NAWQA) program in the last decade describe water-quality conditions in nearly 120 agricultural and 35 urban watersheds ('urban' primarily refers to residential and commercial development over the last 50 years). The findings show that for both urban and agricultural areas, nonpoint chemical contamination is an issue. Much work still needs to be done in urban areas with point source contamination as well, including infrastructure improvements. Appreciable improvements in overall water quality, however, will depend upon effective management of point and nonpoint sources. The findings show that nonpoint chemical contamination is an agricultural and urban issue. Whereas a lot of work still needs to be pursued with point source contamination and infrastructure improvements in urban areas (such as related to combined and sanitary sewer overflows), appreciable improvements in water quality also will depend upon management of nonpoint sources. The NAWQA findings also show that water-quality conditions and aquatic health reflect a complex combination of land and chemical use, land-management practices, population density and watershed development, and natural features, such as soils, geology, hydrology, and climate. Contaminant concentrations vary from season to season and from watershed to watershed. Even among seemingly similar land uses and sources of contamination, different areas can have very different degrees of vulnerability and, therefore, have different rates at which improved treatment or management can lead to water-quality improvements.

Fact Sheet↗

USGS1968

Ground-water resources of the Acu Valley, Rio Grande Norte, Brazil

The Acu Valley is the lower part of the Rio Piranhas valley in the northwestern part of the State of Rio Grande do Norte, Brazil. It begins where the Rio Piranhas leaves the crystalline Precambrian rocks to flow across the outcrop of sedimentary rocks. The area considered in this report extends northward for about 45 kilometers; it is terminated arbitrarily where encroachment by sea water has contaminated the aquifer and imparted a disagreeable saline taste to the water in it. The boundary was not determined in the field, however, for lack of special equipment. Part of the extensive uplands on either side of the valley are included. This makes the total area approximately 2,500 square kilometers. The largest town, Acu, had a population of about 8,000 in 1960. The area is considered to be part of the Drought Polygon of northeast Brazil because the precipitation, although averaging 448 millimeters annually at Acu, varies widely from year to year and often is deficient for many months. The precipitation has been supplemented by use of irrigation wells, but irrigated agriculture is not yet far advanced, and the quantities of water used in irrigation are small. Geologically, the area consists of basement crystalline rocks (Precambrian), a wedge of sedimentary rocks thickening northward (Cretaceous), and alluvial sediments constituting a narrow band in the bottom of the valley (Alluvium and terrace deposits). The crystalline rocks contain water mainly in fractures and, in general, are impermeable. The sedimentary rocks of Cretaceous age comprise two units: a thick but fine-grained sandstone grading upward into siltstone and shale (Acu Sandstone), and limestone and dolomite with an included shale zone (Jandaira Limestone). The sandstone especially and the limestone to a lesser degree are ground-water reservoirs of large capacity. The limestone has been tapped at several places, but the sandstone and its contained water are practically untested and, hence, imperfectly understood. The alluvium of the first terrace is the aquifer supplying most of the ground water being used in the area. Wells in the alluvium yield as much as S0,000 liters per hour. Larger yields probably could be obtained from wells designated to take full advantage of the aquifer. There are in the valley about 300 dug wells which are used for irrigation. Half of these are equipped with pumps and engines. The rest, together with about 500 drive-point wells, are equipped with manual or windmill-driven pumps. In addition to irrigation, the water is used in homes and for cattle. The quantities of water currently used in irrigation are relatively small, both per hectare and in the area as a whole, but .this will probably increase substantially when intensive irrigation becomes a reality. The annual pumpage from the alluvium, nearly constant since 1959, was about 2.5 million cubic meters in 1964, which is only about 90 cubic meters from each hectare-meter of saturated alluvium. This amount would lower the water table about 1 meter in 11 years, if there were no recharge. Actually, no such decline is likely to occur, because the recharge from precipitation alone is estimated to be more than enough to replace the water currently being pumped. Chemical analyses of eight samples show that the ground water in the alluvium is acceptable for most uses. The water in the Acu Sandstone and Jandazra Limestone is more mineralized than that in the alluvium and at some places, at least, is not acceptable for human consumption. The available chemical data on this water, however, are not adequate to judge fully the quality of the water in these formations. It is estimated that about .'22 million cubic meters of water would be needed annually if irrigation were extended to all the bottom land, which totals about 25,000 hectares. This amount is only one-fourth to one-half the estimated recharge from precipitation alone. The present rate of application of water is very low

Water Supply Paper↗

USGS1986

Organochlorine chemical residues in bluegills and common carp from the irrigated San Joaquin Valley floor, California

Samples of bluegills ( Lepomis macrochirus ) and common carp ( Cyprinus carpio ) collected from the San Joaquin River and two tributaries (Merced River and Salt Slough) in California were analyzed for 21 organochlorine chemical residues by gas chromatography to determine if pesticide contamination was confined to downstream sites exposed to irrigated agriculture, or if nonirrigated upstream sites were also contaminated. Residues of p,p′ -DDE were detected in all samples of both species. Six other contaminants were also present in both species at one or more of the collection sites: chlordane ( cis -chlordane + trans -nonachlor); p,p′ -DDD; o,p′ -DDT; p,p′ -DDT; DCPA (dimethyl tetrachloroterephthalate); and dieldrin. Concentrations of most of these residues were generally higher in carp than in bluegills; residues of other compounds were found only in carp: α-BHC (α-benzenehexachloride), Aroclor ® 1260, and toxaphene. Concentrations of most organochlorines in fish increased from upstream to downstream. Water quality variables that are influenced by irrigation return flows ( e.g. , conductivity, turbidity, and total alkalinity) also increased from upstream to downstream and were significantly correlated ( P < 0.05) with organochlorine residue levels in the fish. In carp, concentrations of two residues-⌆DDT ( p,p′ -DDD + p,p′ -DDE + + p,p′ -DDT; 1.43 to 2.21 mg/kg wet weight) and toxaphene (3.12 mg/kg wet weight)-approached the highest levels reported by the National Pesticide Monitoring Program for fish from other intensively farmed watersheds of the United States in 1980 to 1981, and surpassed criteria for whole-body residue concentrations recomended by the National Academy of Sciences and National Academy of Engineers for the protection of piscivorous wildlife.

California↗