Statistics

Basin size: 1260 sq km (491 sq mi)

Land use: predominantly agricultural, including old order Amish and Mennonite families; about 65% is cropland or pasture; about 25% forested, about 10% urban
Population: approximately 300,000 in the city of Lancaster; population growth is on the order of 4000/year

Geology/Soils: Most of the basin is underlain by limestone/dolomite with karst development, numerous sinkholes. Good agricultural soil.

Water resources: The Conestoga River is the water supply for 175,000 including the city of Lancaster. Half the drinking water for the City comes from the Conestoga. Several exceptional value and high quality streams have been designated, along with a trout stream (Segloch Run).

Cattle grazing on karst aquifer. Photo by Brucxe Lindsey,
USGS (Lindsey et al, 1998)

Hydrology

Recharge is 30 to 40 cm/year (11 to 15 inches/year). Drainage is either dendritic or karstic (no drainage pattern, but numerous sinkholes and springs). Very few wetlands remain. In the carbonate rock areas, baseflow is high, typically 84% of streamflow. Conduits and fractures, with high transmissivity, typically control groundwater flow direction.

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Major issues in the basin

Nutrients, pesticides, and bacteria: The basin has some of the highest density of dairy farms in Pennsylvania. Poultry and hog farming are also high density. Along with crop and karst development, this leads to significant levels of nutrient and pesticide contamination in surface and subsurface water. Several reports detailing contamination are available from the USGS. About 1/3 of the well samples have found fecal coliform, most wells exceed the 10 mg/L standard for nitrate, and several herbicides have been detected in wells.

Soil erosion: Lack of stream bank stabilization and heavy agriculture has led to soil erosion and sediment-laden discharge in streams. Erosion rates on the order of 10 tons per acre have been reported.

Sewage discharge: About 50 percent of the county’s sewage is discharged to the Conestoga River. Both industrial and municipal discharge permits have been issued in the basin. Although normally treated, raw sewage may be discharged during storms.
Mining: The basin receives discharge from mining. Abandoned mines are a growing problem in the state.

Development: Farmland is threatened with paving for development. Urban land use is projected to increase from 10% to 25% in the next 25 years. Development will affect streamflow and flooding.

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Existing monitoring

Wells: There are numerous private and public wells in the basin, with approximately 30% of the population supplied by groundwater (approx 20,000 wells).

Stream gages: USGS has two stations in the basin with long term records (dating back to 1928 in one case and 1984 in the second). There are also numerous gages on tributaries with shorter term records. Dickinson College has a well monitoring field near Boiling Springs, adjacent to the Conestoga Basin.

Weather stations/atmospheric monitoring: The national weather service has two stations near Lancaster and the USGS has a station near Ephrata.

GIS: The Susquehanna River Basin Commission, state, county, and Penn State all have GIS databases for the basin.

Geochemical labs: extensive labs are available at local universities and colleges (see logistics)

Experimental plots: The USGS has had several experimental plots in the basin to assess agricultural management practices. For example, near Churchtown is a 22-acre plot with 10 monitoring wells used to evaluate agricultural conservation practices. In addition, both the EPA and DEP have funded more than 2 dozen watershed restoration projects in the basin. For example, the Lititz Run Watershed Alliance restored riparian buffers and wetlands. The USGS conducted a study of the water quality changes after fencing to prevent livestock intrusion. Several land trust grants have been made to preserve open space. These plots are potential sites for future monitoring studies.

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Agencies & cooperators

USGS (e.g., NAWQA study area involving 1200 samples, 500 sites)
Susquehanna River Basin Commission
Townships, Lancaster Co
DEP (funded more than a dozen GG grants on restoration & education)
EPA ditto
ARS
Watershed associations (7)
Water conservation district
Troutfishing Unlimited

Logistics

Nearby Harrisburg International Airport, 1.5 h from Philadelphia International Airport and Amtrak in Philadelphia. Minute from Pennsylvania Turnpike, near Lancaster, PA.

The basin is in between Penn State Univ and Temple Univ (and others in Philadelphia). Local colleges in Lancaster Co or York Co include Franklin and Marshall, Millersville, Dickinson, Elizabethtown, York. (The first 3 have geology departments.) Several modest-sized conference centers near Lancaster (www.padutchcountry.com).

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Future work

Follow up monitoring on experimental plots to evaluate effectiveness of remediation measures will be conducted. These plots can be further developed to address questions about sustainability and climate. More detailed instrumentation could be added and sites could be manipulated. For example, one plot could be subjected to different styles of paving. Another plot could be subjected to different agricultural applications. Controlled infiltration and monitoring would be part of all of the plots.

Conestoga River Basin outlined in blue over the Lower Susquehanna River Basin.

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References (there are many USGS reports, only a small selection is presented here)

Bickford, T.M., B.D. Lindsey, and M.R. Beaver. 1996. Bacteriological quality of ground water used for household supply, lower Susquehanna River Basin, Pennsylvania and Maryland. U.S.Geological Survey WRI-96-4212.

Chang, H, 2003. Basin Hydrologic Response to Changes in Climate and Land Use: The Conestoga River Basin, Pennsylvania. Physical Geography 24 (3): 222-247.

Galeone, D.G. 2000. Preliminary effects of streambank fencing of pasture land on the quality of surface water in a small watershed in Lancaster County, Pennsylvania. U.S. Geological Survey WRI-00-4205.

Hainly, R.A., Bickford, T.M., and Lindsey, B.D., 2001, Summary of factors affecting pesticide concentrations in wells and streams of the Lower Susquehanna River Basin, Pennsylvania and Maryland, 1993-95, U.S. Geological Survey Water-Resources Investigations Report 01-4012, 75 p.

Hall, D.W., 1993. Effects of pipe-outlet terracing on ground-water quantity near Churchtown, Pennsylvania. Ground Water, 31 (1): 41-49.

Hall, D.W. and Risser, D., 1993. Effects of agricultural nutrient management on nitrogen fate and transport in Lancaster County, Pennsylvania. Water Resources Bulletin, 29 (1): 55-76.

Lietman, P.L., Gerhart, J.M., and Wetzel, K.L. 1989. Comparison of methods for sampling dissolvednitrogen in a fractured carbonate-rock aquifer. GWMR, 9(1): 197-202.

Lindsey, B.D., Loper, C.A., and Hainly, R.A., 1997, Nitrate in ground water and stream base flow in the Lower Susquehanna River Basin, Pennsylvania and Maryland: U.S. Geological Survey Water-Resources Investigations Report 97-4146, 66 p.

Lindsey, B.D., Breen, K.J., Bilger, M.D., and Brightbill, R.A., 1998, Water Quality in the Lower Susquehanna River Basin, Pennsylvania and Maryland, 1992-95: U.S. Geological Survey Circular 1168

Siwiec, S.F., Hanley, R.A., Lindsey, B.D., Bilger, M.D., and Brightbill, R.A., 1997. Water Quality Assessment of the Lower Susquehanna River Basin: Pennsylvania and Maryland: Design and Implementation of Water Quality Studies, 1992-1995. U.S. Geological Survey OFR 97-583.

Watershed Restoration Strategy (WRAS): State Water Plan Subbasin 07J Conestoga (Susquehanna River) Lancaster, Lebanon, and Berks Counties. September 2003. http://www.dep.state.pa.us/dep/deputate/watermgt/WC/Subjects
/NonpointSourcePollution/ Initiatives/WRASLISTINFO/WrasPlans/WRAS-07J.pdf

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