Statistics

Basin size:Conodoguinet Creek drains an area of 1220 km 2 (470 sq mi) and Yellow Breeches Creek drains an area of 560 km 2 (216 sq mi).

Land use: The land use in the Conodoguinet Creek Watershed is predominantly agricultural, with more than 60 percent of the land in row crop, hay, or pasture with about 30 percent of the land in forest, and 5 percent in urban land use. The Yellow Breeches watershed has a higher proportion of forested land, with 57 percent of the land in forest, 36 percent in cropland, hay, or pasture, and about 6 percent in urban land use.

Population:The two watersheds cover an area that closely matches the boundary of Cumberland County, Pa, which in the 2000 census had a population of 213,674, an increase of almost 20,000 from the population in the 1990 census.

Geology/Soils:Conodoguinet Creek Watershed is underlain by carbonate rocks such as limestone and dolomite (38 percent), sedimentary clastic rocks such as sandstones and shales (60 percent), as well as igneous and metamorphic rocks (2 percent). Yellow Breeches Creek is underlain by the same three types of bedrock. The southern drainage of the Yellow Breeches Creek is underlain by the igneous and metamorphic rocks of the Blue Ridge.

Water resources: Numerous public water supplies use these streams for supply. About 30,000 residents are supplied by ground water from public supply and 160,000 more are supplied by surface water. The remainder of the population relies on private domestic wells. Shippensburg Borough Water Authority and South Middleton Township Water Authority have some of the largest capacity production wells in the state of Pennsylvania.

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Hydrology

The drainage patterns of both the Conodoguinet Creek and the Yellow Breeches Creek are unique Conodoguinet Creek has numerous streams entering the main stem from Blue Mountain and relatively few tributaries from the south draining the Great Valley. Less obvious is the fact that those tributaries flowing to Conodoguinet Creek from the valley originate as large perennial springs. The Yellow Breeches drainage pattern is asymmetrical in nature with almost all tributaries entering the main stem from the south, as runoff from South Mountain. The two streams are interconnected with the Yellow Breeches losing water in some headwaters reaches which is though to be discharged in springs further north in the valley which flow into the Conodoguinet Creek (Chichester, 1996). Recharge is 23 to 35 cm/year for the Conodoguinet and Yellow Breeches Creeks, respectively (9 and 14 inches/year). Average long-term baseflow is of 57 percent of streamflow for the Conodoguinet Creek and 77 percent for the Yellow Breeches Creek. The ground-water flow through, and storage in, the colluvium on South Mountain and flow across topographic divides are important factors in the flow in the two streams.

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Major issues in the basin

Nutrients, pesticides, VOC’s sediment and bacteria: USGS studies showed that water from wells this area had nitrate concentrations that were among the highest in the nation, frequently exceeding 10 mg/L. Bacteria were detected in water from 80 percent of the wells, with fecal coliform detected in up to 30 percent of the wells. The agricultural herbicide atrazine was detected in water from 100 percent of the wells sampled where the surrounding land use was agricultural. VOC’s were detected in water from 80 percent of the wells sampled in this area where the surrounding land use was urban. USGS studies show that the Conodoguinet Creek has one of the highest delivered yields of nitrogen to the Chesapeake Bay, as well as transporting large loads of sediment to the Bay.

Sewage discharge: There are 33 permitted point source discharges (major and minor, industrial and municipal) to Conodoguinet Creek, and 8 permitted point source discharges to Yellow Breeches Creek.

Development: Population has grown by nearly 20,000 in a 10 year period and continues to grow. Residential development is expanding to meet the housing needs of this expanding population. The area is an important transportation corridor. The area has many terminals for the trucking industry and large warehouse facilities are continuing to be built.

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Existing monitoring

Water Quality Monitoring: Letort Spring Run, Conodoguinet Creek, and Yellow Breeches Creek are all monitored as a part of the DEP/USGS Water Quality Network. A study of Cedar Run, an urban tributary to the Yellow Breeches Creek was conducted by the USGS NAWQA project. Data from Conodoguinet Creek is used to calculate loads of nitrogen, phosphorous and sediment to the Chesapeake Bay. Sediment samples have been collected from the Yellow Breeches Creek 3 to 4 times a week for a 10 year period by Dickinson College.

Stream gages: Conodoguinet Creek has a USGS stream gage with a period of record beginning in 1911, Yellow Breeches Creek has a USGS gage with a period of record beginning in 1909. There is also a USGS gage on Letort Spring Run beginning in 1976. Burd Run, a headwaters tributary to the Conodoguinet Creek, has a gage operated by Shippensburg University since 2000.

Monitor Wells: The US Geological Survey observation well network well for Cumberland County is a real-time monitoring well located in the Yellow Breeches Creek Watershed. Dickinson College has a well field used for research near Boiling Springs, Pennsylvania, with periodic water-level measurements. Shippensburg University has 4 shallow wells drilled on the campus for demonstration purposes, as well as several other unused wells on the campus.

Weather stations/atmospheric monitoring: The National Weather Service has stations at Shippensburg, Pa., Bloserville, Pa., and Harrisburg Pa.

GIS:The U.S. Geological Survey and Penn State all have GIS databases for the basin.

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

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Experimental plots:

Ground water: Dickinson College has a well field for field experimentation. Shippensburg also has a study site with nested wells. Several monitor wells drilled for the National-Water Quality Assessment Program urban land use study are available for use in or near Camp Hill, Pennsylvania. Several of these wells are complete in limestone conduits.

Streams: Shippensburg has a stream gage field site where a study of stream restoration has been implemented and water-quality and geomorphic change is being monitored. Dickinson College has a site where changes in stream-channel geomorphology have been monitored on an annual basis for over 15 years.

Agencies & cooperators

USGS (NAWQA study)

Susquehanna River Basin Commission

Townships, Cumberland Co

DEP

EPA

Cumberland County conservation district

Letort Regional Authority

Conodoguinet Creek Watershed Association

Logistics

The site is near the Harrisburg International Airport, and is about 2 hours from Philadelphia International Airport.

The basin is in between Penn State University and the Universities in Philadelphia. Local colleges in Lancaster, York and Cumberland Co. include Franklin and Marshall, Millersville, Dickinson, Shippensburg, Elizabethtown, and York. (The first 4 have geology departments.)

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Future work

The high levels of numerous contaminants in ground water and steams, as well as the large population relying on this resource, make this an important area to study sources and transport of contaminants. The two major bedrock types underlying most of the area give an opportunity to contrast the effect of the underlying geology on both surface and ground water processes. The movement of ground water between surface water basins has been well-documented. This presents an opportunity to study the issue of delineating ground water basins in an area where it is known that ground water and surface water basins do not coincide. The high level of development and urbanization make this an ideal area to study the long term effects of urbanization on runoff and water quality. The presence of existing study sites within the basin provide opportunities to build on the existing base of knowledge about this system.

Conodoguinet and Yellow Breeches Creek Basins highlighted in gray pver the Lower Susquehanna River Basin.

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References

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

Chichester, D.C., 1996, Hydrogeology of, and simulation of ground-water flow in, a mantled carbonate-rock system, Cumberland Valley, Pennsylvania, U.S. Geological Survey Water-Resources Investigations Report 94-4090.

Daly, M.H., and Lindsey, B.D., 1996, Occurrence and concentrations of volatile organic compounds in shallow ground water in the Lower Susquehanna River Basin, Pennsylvania and Maryland: U.S. Geological Survey Water-Resources Investigations Report 96-4141.

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.

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.

Siwiec, S.F., Hainley, 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.

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