Watershed Information
Northern Chester County, Pennsylvania is an area of hills and valleys geologically situated at the top of the Virginia Piedmont region. It is broadly bounded by the Allegheny Group of the Appalachian Mountains far to the west and the New Jersey coastal area far to the east—two factors that contribute significantly to the local climate—often experienced as gray winter periods and near-tropical summers.
The southern part of the county borders the Mason-Dixon line at the Pennsylvania– Maryland border. The county’s northeast border is the Schuylkill River. The Schuylkill begins in the Pennsylvania coal regions and flows to the Delaware River at Philadelphia. To the west are Lancaster and Berks Counties. To the east is Valley Forge National Historical Park, Delaware County and then Philadelphia. Across the Schuylkill River lies Montgomery County. The area is rich in historical significance, especially in respect to the Revolutionary War, and is well-known for beautiful, sweeping countryside.
Five major streams form the watersheds of northern Chester County. The largest of these streams is French Creek. The others include Pickering Creek, Valley Creek, Pigeon Creek, and Stony Run. Of less significance is a series of small stormwater runoff streams at the very northern end of the area referred to collectively as “Direct Schuylkill Drainage.” In all, Green Valleys watersheds cover an area of 151 square miles.
The watershed streams provide a major habitat for aquatic and amphibious life and are generally considered a fly-fisher’s paradise. A cornerstone of the Green Valleys Associations’ mission is to protect this environment in both its water and landscape forms. The necessity for this is increasing at an alarming rate as the Philadelphia metropolitan area presses outwardly into the region. In spite of this expansion, the watershed streams within the protection of Green Valleys are all afforded Special Protection by the Commonwealth of Pennsylvania—a distinction worth preserving.
French Creek Watershed
The French Creek watershed has a drainage area of 70.2 square miles of primarily open space, farms and small villages. It has over 20,000 acres of land preserved in national, state and county parks, state game lands and conservation easements. It also contains many environmentally sensitive areas as inventoried by the Pennsylvania Natural Diversity Index. There are 30 historic structures along the creek listed on the National Register of Historic Places. The waters are stocked annually with over 40,000 trout.
This creek was designated a Pennsylvania Scenic River in 1982. In 1997 it was upgraded from High Quality to Exceptional Value and in 1998 was placed on the Conservation River Registry. French Creek is the common thread through a valley that served as a focus for planning and protection by the Federation of Northern Chester County Communities, which Green Valleys Association helped to form in 1971. GVA and the Federation plan to present an Integrated Water Resources Plan to the Delaware River Basin Commission to guide the future management of the water supply, wastewater recycling and storm water in the northern Chester County communities.
Pickering Creek Watershed
The Pickering Creek watershed covers an area of 38.8 square miles. Its headwaters begin around Lionville at its western end. To the east, just before entering the Schuylkill River below Phoenixville, it accumulates in a large public water supply reservoir maintained by the Philadelphia Suburban Water Company. The major threat to water quality of the creek and the reservoir is sedimentation from storm water runoff. After Valley Creek, Pickering Creek is the southeastern-most watershed in Green Valleys scope, placing it very close to the metropolitan expansion of Philadelphia and adjoining Great Valley Corporate Center—the region’s “Silicon Valley.” As a result, both watersheds are encountering a tremendous amount of developmental pressure. Both ends of the Pickering Creek watershed have become highly developed with the center section filling rapidly.
The Pennsylvania Department of Environmental Protection has given the Pickering Creek a “High Quality” designation which extends special protection by the state. As a result of the efforts of Green Valleys Association, the Pickering Creek was placed on the Conservation River Registry in 1998.
Valley Creek Watershed
Valley Creek is a 23.4 square mile watershed that is closer to the Philadelphia Metropolitan area than any of the other Green Valleys Association watersheds. Because of this location, it has experienced the most dramatic change in development of any area within GVA. Valley Creek traverses 430 acres of the region known as the “Great Valley.” It flows through Great Valley Corporate Center (the high-tech center of the area), and Chesterbrook (along the US Route 202 corridor), to it’s mouth at the Schuylkill River in Valley Forge National Historical Park (VFNHP). It is a Class A trout fishery with nature preserves, parks and lands under conservation easement along the stream. In 1993, Valley Creek was awarded the highest protection the Commonwealth of Pennsylvania has to offer: Exceptional Value.
The extensive residential and commercial development that has affected Valley Creek in the last decade-and-a-half has caused a major shift in water dynamics in the area. Unlike the other GVA watersheds, which depend primarily on a system of private wells and private septic systems, Valley Creek has evolved to a system of public water supply and public sewers. The result of this self-contained system is that water supplies in the area are no longer directly dependent on the groundwater feeding the Valley Creek. This in and of itself does not lessen the importance of the quality of the stream, and it remains a significant member of the ecosystem in the area. It is a major resource to Valley Forge National Historical Park and is a volume contributor to the water supply of the Schuylkill River.
Great Valley lies on a significant limestone vein passing through southeastern Pennsylvania and extending into New Jersey. The quarrying of limestone is an important industry in the area. As a result, the area is pocked by many quarries and frequently suffers disruptive sinkholes that occur in area highways when acid rain erodes the limestone base beneath the road.
Pigeon Creek Watershed
The Pigeon Creek Watershed, covering 14.4 square miles, is one of the smaller watersheds protected by GVA. Its territory is mostly in the Coventry Townships: South, East, and North. Pigeon Creek has Special Protection, designated as a High Quality Stream.
Stony Run Watershed
Stony Run watershed covers an area of 5.6 square miles and is the smallest watershed of the five watersheds protected by Green Valleys Association. The Stony Run is classified as a High Quality Trout Stocking Fishery (PA DEP). In 2003, Stony Run Watershed and its associated tributaries that directly flow into the Schuylkill River were placed on the Pennsylvania Rivers Conservation Registry under the Department of Conservation and Natural Resources. In the last several years, development and the impact of homeowner land management have taken their toll on the watershed.
Stony Run flows through the northern Chester County townships of East Coventry, East Vincent, and East Pikeland. It enters the Schuylkill River below Spring City, a borough named for the numerous springs which supply it and Stony Run. The majority of the sub-basin can be described as growing suburbs in the portions adjacent to the existing borough, with the remaining areas still rural and supporting some active farming. Some of these farms, however, are struggling and pressures to sell land for development are increasing.
Direct Schuylkill Drainage Zone
The Schuylkill Drainage zone consists of a series of small streams and runoff areas along the Schuylkill River that are a part of the vast Schuylkill River Watershed. A portion of this watershed covering northern Chester County falls within the boundaries of Green Valleys Association. Though not all of these streams are worthy of high-quality ratings, this drainage area is important in regard to flood control and the overall quality of the Schuylkill River in general, and therefore is of concern to Green Valleys.
The drainage area itself is one of farms, industry, and boroughs along the river. Animal waste, fertilizer and other farm chemicals must be prevented from contaminating the Schuylkill River which provides water to the boroughs of Spring City, Royersford, and Phoenixville plus downriver cities including Norristown and Philadelphia.
Storm water must be allowed to percolate into the ground as much as possible rather than to be accumulated in manmade receptacles such as parking lots and streets, only to be channeled into the river. The diversion of storm water to the river has a cumulative effect along the river which strains its capacity and causes flooding in low-lying areas.
Flooding conditions such as those experienced with Hurricane Agnes in 1972 are not common by any means, but excessive rains will stress any groundwater removal system. It is only by properly maintaining the drainage area that the exacerbation of flooding can be reduced.
State of Our Watersheds Report
By Dr. Ralph Heister Jr., and Emily B. Geer
edited by Pam Baxter
March, 2001
A stream is a barometer of change in a watershed. When precipitation falls, it either evaporates from the soil, is incorporated into the groundwater, or it runs off into streams, carrying pollutants with it. If the precipitation is heavy enough, especially with an increase in paving and other impervious surfaces, the runoff may also cause stream flooding. By monitoring stream water quality and quantity, we can monitor the impact of changes within a watershed.
This is the inaugural issue of the Green Valleys Association “State of Our Watersheds” report, covering the five watersheds in eastern and northern Chester County: Valley Creek, Pickering Creek, French Creek, Pigeon Creek and Stony Run. These watersheds are of such high quality that the Pennsylvania Department of Environmental Protection designated them for Special Protection. Together they encompass an area of 158 square miles.
The purpose of this and subsequent annual watershed reports is to document the present condition of these five streams and watersheds, and how they are changing over time under the pressure of development. We will call attention to the major land use issues in each watershed that impact the stream water quality and quantity.
Sustainable Watershed Management
As a region, we in northern and eastern Chester County are almost entirely dependent on groundwater for our water supply. Therefore, it is important to know how much water we have and where it is, and to husband it as a precious resource. From 1995 to 1998, Green Valleys Association (GVA) developed a program that, if followed, will enable residents within the watershed area to live within present water resources. The program calls for the reduction of runoff by infiltrating stormwater to the maximum extent possible. It also calls for wastewater to be recycled by land application, i.e., not discharged directly into streams.
This program is known as Sustainable Watershed Management, and it has been met with broad support. Many of the townships within the watersheds of Pigeon Creek, Stony Run and French Creek have recently passed—or are developing—ordinances that will protect their water resources in order to sustain their streams and groundwater, and that will sustain development as well.
Stream Flows – Stream Health
For each of the streams in our five-watershed area, this report includes a brief survey of the biological stream health, major land use issues within the watershed affecting stream quality and quantity, and the overall present condition of the stream. Where the U.S. Geological Survey (USGS) has a continuous recording gauge (at Valley Creek and French Creek), this report also includes stream flows for 1999.
The data on stream health are from the Chester County—USGS biological diversity— monitoring program. The Hilsonhoff Biotic Index (HBI), shown in Table 1, is based on pollution tolerance of stream macro-invertebrates. The lower the index value, the higher the water quality.
Table 1.
The Hilsonhoff Biotic Index scale is used to interpret
organic pollution data for our five streams.
HBI |
WATER QUALITY |
DEGREE OF ORGANIC POLLUTION |
0.00 - 3.50 |
Excellent |
No apparent organic pollution |
3.51 - 4.50 |
Very Good |
Possible slight organic pollution |
4.51 - 5.50 |
Good |
Some organic pollution |
5.51 - 6.50 |
Fair |
Fairly significant organic pollution |
6.51 - 7.50 |
Fairly Poor |
Significant organic pollution |
7.51 - 8.50 |
Poor |
Very Significant organic pollution |
8.51 - 10.50 |
Very Poor |
Severe organic pollution |
Note: There is a lag from data collection to data availability by the USGS. Therefore the most recent available data are used in this report.
Watersheds in our region include:
French Creek
Pickering Creek
Valley Creek
Pigeon Creek
Stoney Run