The Study Unit is primarily within the Appalachian Plateau physiographic province, which is dominated by gently warped or tilted layers of sandstone and shale. The province is a ruggedly hilly area, mountainous in part and containing dissected plateaus and broad ridges. The Appalachian Plateau province holds the bulk of the world's bituminous coal deposits. A very small southeastern area of the Study Unit is located within the Valley and Ridge physiographic province. The Valley and Ridge province is characterized by deformed rock layers of resistant sandstone which form long, narrow ridges separated by long valleys underlain by limestone and shale (U.S. Geological Survey Water-Supply Paper 2275, 1984). Both of these provinces can be grouped together as part of the greater region known as the Appalachian Highlands. The Study Unit can be further subdivided into the Southern New York, Middle, Allegheny Mountain, and Kanawha physiographic sections.
The Study Unit includes six ecoregions, including the; Northern Appalachian Plateau, Erie/Ontario Hills and Lake, North Central Appalachians, Ridge and Valley, Central Appalachians, and the Western Allegheny Plateau regions. Ecoregions denote areas within which ecosystems (the type, quality, and quantity of flora and fauna) are generally similar.
Spatial data sets for the conterminous United States are available from the U.S. Geological Survey for physiography and ecoregions.
The land surface of the Study Unit is underlain by sedimentary rocks, including sandstone, shale, coal, and limestone, of Pennsylvanian, Mississippian, and Devonian age. These rocks have been fractured and faulted in many areas resulting in a complex hydrogeologic setting. The bedrock is blanketed by a layer of weathered rock material, Quaternary glaciofluvial deposits and alluvium. The weathered rock material is generally thin (less than 20 feet), the glaciofluvial deposits, present only in the northern part of the Study Unit, commonly range in thickness from 20 to 500 feet, and the alluvium is generally less than 100 feet thick (McAuley, 1995).
Soils in areas of steep slope are commonly shallow, poorly developed and drained, with low fertility and high erosion potential. Soils on less steep slopes and over unconsolidated sediments are commonly deep, well-drained and fertile (McAuley, 1995).
Spatial data sets for the conterminous United States are available from the U.S. Geological Survey for surficial geology, the State Soil Geographic (STATSGO) Data Base, and STATSGO soil characteristics.
The two major hydrogeologic settings in the Study Unit are the (1) unconsolidated glaciofluvial and alluvial sediments, and (2) fractured and folded sedimentary rocks. Many of the major Quaternary aquifers are in buried bedrock valleys. The alluvium sediments are also excellent sources of ground water in major river valleys. Yields from ground-water flow systems in the fractured rocks are difficult to predict, highly variable, and commonly of local extent (Piper, 1933, p. 31). The average annual recharge is estimated to range from 8 to 15 inches (McAuley, 1995).
The ALMN NAWQA study areas for ground water include the fractured rock and the glaciofluvial settings. More information is available on the ALMN NAWQA ground-water quality studies on the Ground-Water Study Components page.
Spatial data sets for the conterminous United States are available from the U.S. Geological Survey for principal aquifers, principal productive aquifers, and ground-water regions.
The Allegheny and Monongahela River Basins drain approximately 19,145 square miles of New York, Pennsylvania, Maryland, and West Virginia. The rivers join in Pittsburgh, Pennsylvania to form the Ohio River. Approximately 66 percent of the Study Unit is located within Pennsylvania, followed by 22 percent in West Virginia, 9.7 percent in New York, and 2.3 percent in Maryland. Streamflow in much of both major river basins is controlled by reservoirs, which are used mostly for flood control, and some for recreation and water supply, as well as for controlling water quality and navigation during low flows. A series of locks and dams permits navigation over about 50 miles of the Allegheny River and over approximately 100 miles of the Monongahela River (McAuley, 1995). More information on the ALMN NAWQA surface-water quality studies is available on the Surface-Water Study Components page. Major towns and selected streams are identified on the following figure:
The Allegheny River has a length of 295 miles with its
headwaters starting near Coudersport, Pennsylvania. The Allegheny
River drains about 11,805 square miles of New York and
Pennsylvania. The ALMN NAWQA sub-basins of the Allegheny River
Drainage Basin include:
- Allegheny River at New Kensington, PA (Outflow Integrator site)
- Allegheny River at Eldred, PA
- French Creek at Utica, PA
- French Creek at Venango, PA
- French Creek at Meadville, PA
- East Hickory Creek near Queen, PA
- Stonycreek River at Ferndale, PA
- South Branch Plum Creek at Five Points, PA
- Conewango Creek at Russell, PA
- Clarion River at Ridgeway, PA
- Deer Creek at Dorseyville, PA*
*(Actually located below Allegheny River at New Kensington Outflow Integrator site)
The Monongahela River headwaters begins near Fairmont,
West Virginia. The Monongahela River has a length of 116 miles
and drains about 7,340 square miles of Maryland, Pennsylvania and
West Virginia. The ALMN NAWQA sub-basins of the Monongahela River
Drainage Basin include:
- Monongahela River at Braddock, PA (Outflow Integrator site)
- Monongahela River at Hoult, PA
- Cheat River near Mount Nebo, WV
- Dunkard Creek at Shannopin, PA
- Youghiogheny River at Sutersville, PA
- Coxes Creek above Wilson Creek at Rockwood, PA
- Tygart Valley River near Elkins, WV
- Laurel Hill Creek at Ursina, PA
- Tenmile Creek at Amity, PA
Spatial data sets for the conterminous United States are available from the U.S. Geological Survey for 1:2,000,000-scale Digital Line Graph streams and for selected characteristics of large reservoirs.
The climate of the Study Unit is temperate. The average
annual temperature is 49 degrees Fahrenheit. Mean monthly
temperatures range from 29 to 72 degrees Fahrenheit. Average
annual precipitation is 42 inches and ranges from 37 inches in
northern areas to 60 inches in the southern, mountainous areas.
The normal precipitation in western Pennsylvania is somewhat
varied from month to month, with the greatest precipitation
occurring in June in the northern part of the area and in July in
the southern part. The least monthly precipitation at most of the
Weather Bureau stations occurs in November, though at some
stations it occurs in other months. In general, the amount of
precipitation is closely related to the topography, the uplands
of the eastern, mountainous area receiving a maximum and the
lowland valleys receiving a minimum of rain and snow (Piper, 1933, p. 6).
Climate Data Collection Networks
There are three National Atmospheric Deposition Program/National Trends Network (NADP/NTN) monitoring stations used to collect meteorological information located within the Study Unit. Meteorological data is collected at stations in the Kane Experimental Forest (Allegheny National Forest, PA), the Northeastern Forest Experiment Station (Parsons, WV), and in Chautauqua (Chautauqua County, NY). Additional climate data is collected at three Primary Stations of the National Climate Data Center (NCDC). These sites are located at the Greater Pittsburgh International Airport (PA), Port Meadville Airport (PA), and the Elkins-Randolphy County Airport (WV).
Spatial data sets for the conterminous United States are available from the U.S. Geological Survey for the Hydro-Climatic Data Network (HCDN) -- A USGS streamflow data set for the U.S. for the study of climate fluctuations, and for climate divisions from the National Climatic Data Center.
A breakdown of the land uses (Landsat Thematic Mapper (TM) Data, 1992) in the Allegheny River Basin and the Monongahela River Basin are shown in the following pie chart. A land-use map is also available for viewing.
Land Use in the Allegheny River Drainage Basinland use land use land use Classification (in sq. miles) (by %) --------------------------------------------- Open Water 156.9 0.8 Urban/Commercial 429.9 2.3 Hay/Pasture 1421.1 7.5 Row Crops 2519.6 13.3 Lawns/Parks/Gulf C. 28.2 0.1 Everygreen Forest 804.0 4.2 Mixed Forest 13219.6 69.9 Wetlands 148.1 0.8 Surface Mine/Quarry 196.4 1.0 -------------------------------------------- Totals 18923.7* 100.0 *Data derived from 1992 Landsat Thematic Mapper (TM) Multispectral Resolution Land Cover (MRLC) digital data. Land use statistics calculated to sample outfall locations and do not include the area downstream of the outfall locations (i.e., approximately 222 sq. miles undescribed)
Mixed and evergreen forests and agricultural land uses
dominate the Allegheny River Basin and, despite its small
percentage of overall land use, coal mining significantly affects
the basin water quality. A breakdown of land use in the Allegheny
River NAWQA sub-basins (Landsat
Thematic Mapper (TM) Data, 1992) is provided in the following
Land Use in the Monongahela River Drainage Basin
By percentage, mixed and evergreen forests and
agricultural land uses dominate the Monongahela River Basin, and,
despite its small percentage of overall land use, coal mining
significantly affects the basin water quality. A breakdown of
land use in the Monongahela River NAWQA sub-basins (Landsat Thematic Mapper (TM) Data,
1992) is provided in the following figure:
Although surface mine land use accounts for only approximately 1% of land use within the ALMN Study Unit, surface and underground coal mining has been a significant source of contamination to surface and ground waters in the basin. The following excerpt, about the Pennsylvania Coal Fields is from the Pennsylvania Coal Data 1997 Report, provided by the Pennsylvania Coal Association:
"Pennsylvania lies at the northeastern end of the Appalachian Coal Basin. Bituminous coal underlies more than 13,000 square miles in coalfields reaching across the western and central parts of the state. Pennsylvania's coalbeds are interlaid with layers of sandstone, shale and limestone. About 40 beds are mined in the state. Major suppliers of coal include the Pittsburgh, the Upper and Lower Freeport, and the Upper and Lower Kittanning. These five beds, ranging from three to six feet thick, account for about 75 percent of the state's coal output. Historically, the most important coalbed in the United States is the Pittsburgh, a seam of bituminous coal averaging more than five feet thick and mined in Pennsylvania, Ohio, West Virginia, and Maryland. In 1996, Pennsylvania ranked 4th in coal production in the United States, while West Virginia ranked 2nd, Ohio ranked 11th, and Maryland ranked 18th."
Information on mine-drainage related projects can be found at Coal-Mine-Drainage Projects in Pennsylvania on the U.S. Geological Survey Pennsylvania Water Science Center website. Coal-related maps for the Appalachian region and the United States are available from the Eastern Energy Resources Team of the U.S. Geological Survey. In addition, the Office of Surface Mining (OSM) is a good resource for additional coal-mining related information and World Wide Web links. A map showing the approximate extent of coal fields (Tully, 1996) in the ALMN Study Unit is available for viewing:
The basin is in all or part of 48 different counties and includes more than 1,100 surface-water and ground-water public water-supply withdrawals. In 1990, water withdrawn from aquifers and surface water in the Allegheny-Monongahela Study Unit averaged 3,531 million gallons per day, most of which was surface-water withdrawal. Nearly all water supply in the Pittsburgh area is withdrawn from surface water. Water withdrawals were used for thermoelectric power (66 percent of total water withdrawals), public water supply (12 percent of total water withdrawals), and for industrial and mining purposes (19 percent of total water withdrawals). Only 2 percent of the water withdrawn was from ground water for public supply, and about 1 percent of total water withdrawn was for self-supplied domestic water supply (McAuley, 1995). Ground water provides the domestic water supply of almost all rural residents in the Study Unit.
Spatial data sets for the conterminous United States are available from the U.S. Geological Survey for 1:2,000,000-scale state boundaries, city locations for all places in the TIGER files, and for 1:100,000-scale counties.