U.S. Geological Survey
U.S. Geological Survey
The USGS provides maps, reports, and information to help others meet their needs to manage, develop, and protect America's water, energy, mineral, and land resources. We help find natural resources needed to build tomorrow, and supply scientific understanding needed to help minimize or mitigate the effects of natural hazards and environmental damage caused by human activities. The results of our efforts touch the daily lives of almost every American.
Figure 1. Locations of example U.S. Geological Survey studies.
In the Hatboro area of Bucks and Montgomery Counties, the USGS, in cooperation with the USEPA, conducted a study of ground-water contamination centered around an industrial area established before 1945 (fig. 1, site 2). The area is underlain by the Stockton Formation, which consists of sandstone and siltstone. Most public-supply, industrial, and monitoring wells drilled before 1991 are open boreholes that obtain water from several water-bearing zones. These wells commonly short circuit the ground-water-flow system and act as conduits for the transport of contaminants between water-bearing zones (fig. 2).
Figure 2. Contamination of ground water caused by abandoned boreholes.
USGS scientists used a combination of borehole-geophysical methods, measurements of vertical borehole flow, and analyses of borehole-fluid samples to identify and assess aquifer cross-contamination in the Hatboro area. Borehole-geophysical methods were used to identify zones of fluid movement, and borehole-flow measurements provided data on the direction and rate of fluid movement. Sampling and chemical analysis showed that the downward-moving borehole fluid was contaminated with volatile organic compounds. In nine open boreholes, about 15 gallons per year of these compounds were moving downward from the contaminated upper part of the aquifer to the lower part of the aquifer, which is tapped by public-supply wells. Trichloroethylene, which is an industrial degreaser, accounts for 94 percent of the compounds. In response to the study results, five of the sampled boreholes plus four others, were cased and screened. The remaining four sampled boreholes were reconstructed by the USGS so that they are now open only to a single water-bearing zone. The aquifer cross-contamination problem caused by known boreholes and the associated threat to ground-water quality was eliminated.
Geologic and Hydrologic Mapping
Bedrock and surficial geologic maps and hydrologic maps are prepared by the USGS. These maps are essential for studies of water contamination, resource availability, environmental effects of mineral extraction, hazard mitigation, and land-use management.
Wellhead Protection
The USGS has assisted the Pennsylvania Department of Environmental Resources in implementing a wellhead-protection strategy by providing an evaluation of methods used to delineate areas contributing water to wells in various hydrologic settings. This effort helps local jurisdictions develop regulations to protect public ground-water supplies from contamination. For example, the Lehigh-Northampton County Joint Planning Commission, with assistance from the USGS, has developed a wellhead-protection strategy (fig. 1, site 3). Geologic maps have been used to prepare several geographic information system data layers, including a regional pollution-potential map. Additionally, USGS publications are used for the Commission's public outreach activities.
Effects of Agricultural Practices on Water Quality
Agriculture is a source of sediment, nutrients, and herbicides to water resources. USGS studies in agricultural areas in the lower Susquehanna River Basin, which drains to Chesapeake Bay, have documented accelerated erosion of cropland and streambanks, high concentrations of nitrogen and phosphorus in streams that create conditions detrimental to aquatic life, and elevated concentrations of nitrogen and herbicides in ground water that pose potential human and livestock health hazards.
A USGS study in Lancaster County (fig. 1, site 4) showed that in ground water in areas underlain by carbonate rock, where intensive agricultural practices are concentrated, the criterion for nitrate in ground water was exceeded in about 75 percent of the wells sampled, and the herbicide atrazine was present in low concentrations in about 40 percent of the wells sampled. Concentrations of nitrogen and phosphorus in the streams were consistently greater than concentrations known to cause eutrophic conditions, and concentrations of nitrate and herbicide commonly exceeded criteria for drinking water. Ground-water discharge contributed about 65 percent of the nitrogen in streamwater. About 75 percent of the phosphorus and more than 95 percent of the sediment in the stream were from storm runoff. The effects of agriculture on yields of nitrate and total phosphorus in selected streams is shown in figure 3. Reservoirs on the Susquehanna River have helped to trap some of the sediment, nitrogen, and phosphorus before it enters Chesapeake Bay. However, USGS data indicate that all the mainstream reservoirs are nearly filled with sediment and thus cannot continue to trap pollutants indefinitely.
Figure 3. Average annual dissolved nitrate and total phosphorus yields as a function of agricultural land-use area in selected streams in the Susquehanna River Basin.
The USGS evaluated agricultural-management practices in the Conestoga River headwaters in Lancaster County as part of a national U.S. Department of Agriculture program supported by many Federal, State, and local agencies, such as the USEPA, the Pennsylvania Department of Environmental Resources, and the Lancaster County Conservation District. At a farm field where pipe-outlet terraces were constructed, USGS scientists found reduced soil erosion, but nitrogen and phosphorous losses to surface runoff did not differ significantly before and after terracing. However, concentrations of nitrate in water in four of the six wells at this site increased following terracing. At a nearby farm field, implementation of nutrient management, which is a practice of balancing fertilizer applications with crop needs, resulted in a 25-percent reduction in fertilizer applications. Concentrations of nitrate in water from three of four wells at this site decreased after nitrogen applications decreased. Nutrient management also stopped the upward trend in concentrations of nitrate in surface water.
Coal Mine Discharges
Acidic drainage from abandoned and active coal mines has contaminated thou- sands of miles of streams and associated ground water in Pennsylvania and is the most extensive water-pollution problem in the State. Elevated concentrations of sulfate and metals make the water unfit for most uses and are toxic to aquatic organisms. USGS studies have documented the extent of surface- and ground-water contamination associated with bituminous coal mining in western Pennsylvania and anthracite coal mining in eastern Pennsylvania and have evaluated the effects of mining and reclamation practices and water-treatment methods intended to reduce contamination. These studies have been supported by funds and services from the U.S. Environmental Protection Agency, the Office of Surface Mining, the Pennsylvania Department of Environmental Resources, the Philadelphia Water Department, and the Somerset County Conservation District. Coal companies and the Pennsylvania State University also have participated in these studies.
USGS studies provide a basis for identifying discharges and selecting remedial actions. In the Stonycreek River Basin in Somerset and Cambria Counties (fig. 1, site 5), a streamflow model that simulates chemical reactions is being tested to determine the cumulative downstream effects of treatment of selected discharges in the basin. In the Swatara Creek Basin in Schuylkill County (fig. 1, site 6), chemical reactions within different mine-drainage treatment systems are being evaluated to resolve uncertainties about the optimum design of treatment systems.
A recent USGS study evaluated the effects of selective handling of acid-forming materials on ground-water quality at a surface coal mine in Clarion County (fig. 1, site 7). Potentially acidic rock was segregated during mining and subsequently buried in mine backfill as compacted layers below the plant root zone but above the water table. Selective handling did not significantly affect concentrations of metals in ground water at the mine studied.
USGS studies also have evaluated the effects of surficially applied alkaline materials and sewage sludge on ground- water quality at four mines in Clarion and Clearfield Counties (fig. 1, site 8). Additions of alkaline materials typically were inadequate to neutralize acidity from oxidation reactions within the mine spoil. Research into procedures for preventing acid-forming oxidation reactions by adjusting quantities and combinations of alkaline additives and nutrients is continuing.
National Water-Quality Assessment Program
The long-term goals of the National Water-Quality Assessment (NAWQA) Program of the USGS are to describe the status and trends in the quality of a large representative part of the Nation's surface- and ground-water resources and to identify the natural and human factors that affect their quality. The NAWQA Program will produce a wealth of water-quality information that will be useful to policymakers and water managers at the local, State, and national levels.
Three NAWQA Program studies are underway for river basins in Pennsylvania-the lower Susquehanna, the Potomac, and the Ohio (Allegheny and Monongahela) (fig. 4). A NAWQA Program study of the Delaware River Basin (fig. 4) is scheduled to begin in 1997. Communication and coordination among the USGS and other water-resource agencies are key components of the NAWQA Program studies. As the results of these studies become available, they will be disseminated in a variety of technical and nontechnical reports to local, State, and Federal agencies and the public.
Figure 4. National Water-quality Assessment Program study areas in Pennsylvania.
One critical requirement of the NAWQA Program is up-to-date information on land use/land cover to determine their influence on water quality. The USGS, in cooperation with several other Federal agencies, is acquiring satellite image data for the entire United States. After these data are processed according to a consistent standard, they are forwarded to NAWQA Program projects, as well as to other water-resource agencies, for water-quality research and related applications.
Coal Availability
Conventional Federal and State coal-resource estimates do not account for the multitude of societal and physical restrictions to mining that could limit it or affect costs. Consequently, a cooperative program between the USGS and the Pennsylvania Topographic and Geologic Survey was initiated in 1991 to identify and delineate current major restrictions and to estimate the amount of coal reserves that may be available, given those restrictions. Coal-availability data are stored in a national geographic information system that can be used to efficiently analyze and depict the data.
Effects of Federal Rulemaking on Coal Markets
The U.S. Department of Interior, Office of Surface Mining (OSM), is establishing a Federal rule for Valid Existing Rights that could affect access to coal in environmentally sensitive areas and determine whether underground mining should be prohibited in such areas. The USGS will provide coal-resource assessment and economic analysis to OSM to support the rulemaking. Specifically, the USGS is performing work in the following subject areas:
Figure 5. Water-quality-data sites in Pennsylvania.
Cooperative Programs
The USGS cooperates with more than 30 local, State, and Federal agencies in Pennsylvania. Cooperators include State agencies, counties, municipalities, basin commissions, water authorities, universities, and Federal agencies. Cooperative activities include water-resources-data collection, interpretive water-availability and water-quality studies, mineral-resource assessments, mapping, and studies of scour at more than 16,000 highway bridges over water. When local and State agencies are involved, activities typically are funded on a 50:50 matching basis. In addition to the agencies already mentioned, the USGS cooperates with the U.S. Army Corps of Engineers, the Chester County Water Resources Authority, the Delaware River Basin Commission, the Susquehanna River Basin Commission, and the Pennsylvania Department of Transportation, to name only a few.
The USGS provides support to the Environmental Resources Research Institute of the Pennsylvania State University, which conducts a program of research, education, and information and technology transfer.
from U.S. Department of the Interior, U.S. Geological Survey, Fact Sheet FS-038-95