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Yellow perch live in creeks, rivers, ponds, lakes, and estuaries across the central and eastern United States and Canada. In Chesapeake Bay, they tolerate salinities up to one-third that of seawater. The adults reside in the brackish waters of the bay’s tributaries and migrate upstream to spawn. Yellow perch are...

Alaska Natives depend on local natural resources for nutritional and, for many, spiritual health. As a result, public health in Alaska is strongly influenced by the relationship between people and their surrounding physical, chemical, and biological environments. Alaska is vast with diverse wildlife and plant communities that are valued as...

Tallgrass prairie is one of the most imperiled ecosystems on Earth. A 2004 estimate indicated that only 2.4 percent of the original northern tallgrass prairie remained in the United States. If tallgrass prairie and the species dependent on it are to survive, management must include restoration of cropland and degraded...

Arctic and boreal ecosystems provide important breeding habitat for more than half of North America’s migratory birds as well as many resident species. Northern landscapes are projected to experience more pronounced climate-related changes in habitat than most other regions. These changes include increases in shrub growth, conversion of tundra to...

This fact sheet highlights findings included in a comprehensive new report (see USGS Professional Paper 1800) which investigated land-use change, economic characteristics, and rural community well-being in the Prairie Pothole Region of the United States. Once one of the largest grassland-wetlands ecosystems on earth, the North American prairie has experienced...

The Trinity aquifer is an important source of groundwater in central Texas, including Bexar County, where population growth has resulted in an increased demand for water (Ashworth, 1983; Mace and others, 2000). Numerous springs issue from rock outcrops within and surrounding the Trinity aquifer in northern Bexar County (fig. 1)....

The U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Program was established by Congress in 1992 to answer the following question: What is the status of the Nation’s water quality and is it getting better or worse? Since 1992, NAWQA has been a primary source of nationally consistent data and...

The peak discharge of a flood can be estimated from the elevation of high-water marks near the inlet and outlet of a culvert after the flood has occurred. This type of discharge estimate is called an “indirect measurement” because it relies on evidence left behind by the flood, such as...

This fact sheet summarizes basic information on the water resources of Claiborne Parish. Information on groundwater and surface-water availability, quality, development, use, and trends is based on previously published reports listed in the Cited References section. In 2010, about 2.60 million gallons per day (Mgal/d) of water were withdrawn in...

Aquatic biological communities, which are collections of organisms, are a direct measure of stream health because they indicate the ability of a stream to support life. This fact sheet highlights selected findings of a national assessment of stream health by the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological...

Fish populations in the Colorado River downstream from Glen Canyon Dam appear to be limited by the availability of high-quality invertebrate prey. Midge and blackfly production is low and nonnative rainbow trout in Glen Canyon and native fishes in Grand Canyon consume virtually all of the midge and blackfly biomass...

USGS environmental health science focuses on the environment-health interface. Research characterizes the processes that affect the interaction among the physical environment, the living environment, and people, as well as the factors that affect ecological and human exposure to disease agents and the resulting toxicologic or infectious disease. The mission of...

To safely and economically design bridges and culverts, it is necessary to compute the magnitude of peak streamflows that have specified annual exceedance probabilities (AEPs). These peak flows are also needed for effective floodplain management. Annual precipitation and air temperature in the northeastern United States are in general projected to...

In 2010, about 261 million gallons per day (Mgal/d) of water were withdrawn in St. Bernard Parish, Louisiana, almost entirely from surface-water sources. Industrial use accounted for about 97 percent (253 Mgal/d) of the total water withdrawn. Other categories of use included public supply, rural domestic, and livestock. Water-use data...

In 2010, about 85.1 million gallons per day (Mgal/d) of water were withdrawn in Plaquemines Parish, Louisiana. Surface-water sources accounted for almost all withdrawals; groundwater sources accounted for only 0.04 Mgal/d. Industrial use accounted for about 92 percent of the total water withdrawn. Other categories of use included public supply,...

In 2005, about 33.8 million gallons per day (Mgal/d) was withdrawn from water sources in Natchitoches Parish, Louisiana. Surface water sources accounted for about 86 percent (29.2 Mgal/d) of all withdrawals whereas groundwater sources accounted for about 14 percent (4.62 Mgal/d). Withdrawals for industrial use accounted for about 42 percent...

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of Wisconsin, elevation data are critical for agriculture and precision farming, natural resources conservation, flood risk management, infrastructure and construction management, water supply...

The University of Nevada Las Vegas’ (UNLV) Science and Engineering Building is at the cutting edge of environmentally friendly design. As the result of a recent effort by the U.S. Geological Survey’s National Strong Motion Project in cooperation with UNLV, the building is now also in the forefront of buildings...

Natural gas is an important component of the energy mix in the United States, producing greater energy yield per unit weight and less pollution compared to coal and oil. Most of the world’s natural gas resource is thermogenic, produced in the geologic environment over time by high temperature and pressure...

Fine-grained sediment (silt and clay) enters coastal waters from rivers, eroding coastal bluffs, resuspension of seabed sediment, and human activities such as dredging and beach nourishment. The amount of sediment in coastal waters is an important factor in ocean ecosystem health, but little information exists on both the natural and...

The Edwards-Trinity aquifer is a vital groundwater resource for agricultural, industrial, and municipal uses in the Trans-Pecos region of west Texas. A conceptual model of the hydrogeologic framework, geochemistry, and groundwater-flow system in the 4,700 square-mile study area was developed by the U.S. Geological Survey (USGS) in cooperation with the...

The purpose of this fact sheet is to provide examples of how the U.S. Geological Survey is using acoustic Doppler current profilers for much more than routine discharge measurements. These instruments are capable of mapping complex three-dimensional flow fields within rivers, lakes, and estuaries. Using the Velocity Mapping Toolbox to...

The maps and graphs in this summary describe streamflow conditions for water year 2012 (October 1, 2011, to September 30, 2012) in the context of the 83-year period from 1930 through 2012, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Streamflow...

The increasing availability of downscaled climate projections and other data products that summarize or predict climate conditions, is making climate data use more common in research and management. Scientists and decisionmakers often need to construct ensembles and compare climate hindcasts and future projections for particular spatial areas. These tasks generally...

Traditional surface-water surveys are being combined with autonomous technology to produce integrated surveys of bathymetry, water quality, and velocity in inland lakes and reservoirs. This new technology provides valuable, high-resolution, integrated data that allow a systems-based approach to understanding common environmental problems. This fact sheet presents several example applications of...