INTRODUCTION

Since 1969, the U.S. Geological Survey (USGS) has had a

cooperative water-resources investigation program with Chester County to measure and describe the water resources of the

County. Generally, the USGS provides one-half of the program

funding, and local cooperators are required to provide matching funds. Cooperation has been primarily with the Chester

County Water Resources Authority (CCWRA), with participation from the Chester County Health Department and funding

from the Chester County Board of Commissioners. Municipalities and the Red Clay Valley Association also have provided

part of the funding for several projects. This report describes

how the long-term partnership between the USGS and Chester

County, Pa., provides the County with the information that it

needs for sound water-resources management.

The CCWRA was created in 1961, primarily for land acquisition and planning for flood-control and water-supply

projects. With the backing of the Brandywine Valley Association, the CCWRA started its first cooperative project with the

USGS in 1969. It was a study of the water-quality condition of

Chester County streams with an emphasis on benthic macroinvertebrates and stream chemistry.

The kinds of projects and data collection conducted by the

USGS have changed with the needs of Chester County and the

mission of the CCWRA. Chester County is experiencing rapid

population growth (it had the tenth-highest rate of growth in

the nation from 1980 to 1990). This growth places considerable

stress on water resources and has caused the CCWRA to

broaden its focus from flood control to water-supply planning,

water quality, and ground-water and surface-water management. The results of USGS studies are used by the CCWRA and

other County agencies, including the Planning Commission,

Health Department, and Parks and Recreation Department, for

conducting day-to-day activities and planning for future

growth. The results also are used by the CCWRA to provide

guidance and technical assistance to municipalities, water suppliers, industrial dischargers, watershed and conservancy

associations and other civic organizations, state and Federal

agencies, river basin commissions, and the private sector.

The cooperative water-resources program, which is

described in the following sections, benefits not only the citizens of Chester County but also serves the interests of the

Federal Government. Innovative studies conducted in Chester

County provide methods and interpretations that

often can be used nationwide, and the headwaters

of several interstate drainages lie within the

County. Major program thrusts include collection of surface-water, ground-water,

and water-quality data and interpretive studies. The use of this

information also is described.

FLOOD-WARNING NETWORK

As part of the cooperative

program between the USGS and

Chester County, a system of

streamflow-measurement stations is maintained with

telephone access for real-time

stage (depth) monitoring as well as

near-real-time access via the World

Wide Web for monitoring stream stage

and discharge. With this system, County

emergency management personnel and

CCWRA can monitor rising and cresting

floods in key watersheds throughout the County.

This information provides the basis for alerting

emergency response personnel of potential and existing flood conditions. Streamflow is monitored

continuously by the USGS at 14 sites in Chester County.

Three of the stations also are equipped with rain gages

(fig. 1). Eleven of the 14 streamflow-measurement stations are

in cooperation with the Chester County Water Resources Authority

U.S. Geological Survey Cooperative Water-Resources Programs

in Chester County, Pennsylvania

Figure 1. Location of streamflow-measurement stations and

water-quality monitors in Chester County.

U.S. Department of the Interior USGS Fact Sheet 067-98

U.S. Geological Survey June 1998
equipped with data-collection platforms. These platforms

broadcast hydrologic data to a satellite that relays the data to

the USGS District office in Lemoyne, Pa. These data are available on the Internet within a few hours of being collected. A

streamflow hydrograph obtained directly from the USGS Pennsylvania District Web site is shown in figure 2. The hydrograph

shows an increase in streamflow caused by rainfall starting on

April 26, 1998. Land line telemetry that provides instantaneous

values of stream stage also is available at several of the streamflow-measurement stations and is used by County and

municipal emergency management coordinators during severe

weather events to ascertain local flooding conditions. The

CCWRA provides all or part of the funding for eight sites:

French Creek near Phoenixville (USGS station number

01472157), Birch Run near Wagontown (01480400), West Branch

Brandywine Creek at Coatesville (01480500), West Branch

Brandywine Creek at Modena (01480617), Valley Creek at

Pennsylvania Turnpike Bridge near Valley Forge (01473169),

East Branch Brandywine Creek below Downingtown

(01480870), West Branch Brandywine Creek near Honeybrook

(01480300), and Brandywine Creek at Chadds Ford (01481000).

Data from the flood-warning network are used by Chester

County to provide early warning of floods as well as to provide

flood statistics (recurrence interval) and a quantitative basis for

flood plain mapping. Streamflow data from the network are

published by the USGS in annual water-data reports and also

are available on the District Web site.

DATA FOR RESERVOIR MANAGEMENT

Data from several streamflow-measurement stations operated by the USGS are used by Chester County and water

suppliers for managing streamflows and reservoir releases.

Streamflow and water-temperature data collected by the USGS

throughout the Brandywine Creek watershed are used to

determine when reservoir releases are required, how much

release is necessary, and how much release occurs, and also to

insure that interstate water-management requirements are fulfilled. These releases are needed to provide adequate flow of

water for aquatic life, to meet the needs of downstream water

suppliers, and to meet permit requirements. Adequate streamflow during droughts is critical to downstream users in New

Castle County, Del., who obtain 70 percent of their public supply from streams in the Christina River Basin that originate in

Chester County.

DROUGHT-MONITORING NETWORK

Chester County has the only county-wide water-level

observation-well network in Pennsylvania. Since 1973, water

levels have been measured monthly in a network of 23 wells.

Monthly drought-warning and drought-emergency water levels (triggers) have been determined statistically for all but three

of the wells in the network using methods described by Schreffler (1997). Data from the network are used by Chester County

officials and other agencies to make decisions about when to

declare drought watches, warnings, and emergencies. Low

streamflow data for the 14 streamflow-measurement stations in

Chester County and CCWRA’s own network of 29 rain gages

also are used to help make these decisions.

SURFACE-WATER-QUALITY MONITORING

Except during the winter, surface-water quality is monitored on the West Branch Brandywine Creek at Modena

(01480617), on the East Branch Brandywine Creek below

Downingtown (01480870), and on the Brandywine Creek at

Chadds Ford (01481000). Temperature, pH, specific conductance (related to dissolved solids), and dissolved oxygen are

measured hourly, and fecal coliform bacteria are measured

biweekly. These data are used to assess stream health and to

determine trends and detect problems in stream-water quality.

Minimum daily dissolved-oxygen concentrations for 1972-97

for the East Branch Brandywine Creek below Downingtown

are shown in figure 3. Dissolved-oxygen concentrations of less

than 5 milligrams per liter (the minimum concentration needed

to support a healthy aquatic environment) were fairly common

before 1989 but are relatively infrequent from 1989 to 1997.

Figure 2. Example of near-real-time streamflow data from

the USGS Pennsylvania District Web site

(http://pa.water.usgs.gov).

1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 0

16

2

4

6

8

10

12

14

DISSOLVED-OXYGEN CONCENTRATION, IN MILLIGRAMS PER LITER

Figure 3. Minimum daily dissolved-oxygen concentration for the East

Branch Brandywine Creek below Downingtown, Pa. (U.S. Geological

Survey station number 01480870).

ADEQUATE OXYGEN TO SUPPORT AQUATIC LIFE

MARGINAL OR INADEQUATE OXYGEN TO SUPPORT AQUATIC LIFE
GROUND-WATER QUALITY

Since 1925, water from numerous wells in Chester County

has been sampled and analyzed by the USGS for inorganic constituents, nutrients, metals and other trace constituents,

pesticides, volatile and semivolatile organic compounds,

and radionuclides. Some sampling has been targeted

toward industrial areas, landfills, and agricultural

areas. For example, figure 4 shows the distribution of

volatile organic compounds in ground water in Chester County. Results of USGS sampling have been

beneficial to local residents and to the Chester

County Health Department by locating local areas

of ground-water contamination and have contributed to several sites in Chester County being

placed on the National Priorities (Superfund)

List. Also, sampling helped to identify the

Chickies Formation as a source of elevated,

naturally occurring radium and radon in

ground water.

STREAM AND GROUND-WATER

CHARACTERIZATION

Since about 1970, benthic invertebrates and stream water chemistry

are sampled annually at 51 different

sites in Chester County to determine relative stream quality

(health) and long-term changes in

stream quality. The sampling network currently (1998) consists of 43 sites on the major streams

in the County. Each fall, benthic invertebrates are sampled (fig.

5) at 25 of the sites, and a diversity index (a statistic that

describes community structure of benthic invertebrates) is calculated for each site. A low-flow water sample is collected for

laboratory analysis for selected constituents, and bottom sediments are periodically sampled and analyzed for

polychlorinated biphenyls (PCB’s) and organochlorine insecticides (including DDT).

The diversity indices for Valley Creek at Atglen for 1971-96

are shown in figure 6. The substantial improvement (increase)

in diversity from 1971 to 1989, which is typical of most streams

in Chester County, is at least partly the result of decreased concentrations of organochlorine insecticides in bottom sediments

(Hardy and others, 1995).

Since 1981, the USGS has been mapping the elevation and

shape of the water table (for unconfined aquifers) and the

potentiometric surface (for confined aquifers) in Chester

County. Areas of Chester County where the water table or

potentiometric surface has been mapped are shown on figure 7.

These maps can be compared to water table or potentiometricsurface maps prepared at some later time to assess changes

caused by increased ground-water withdrawals and reduced

recharge related to urbanization. They also can be used to

determine the direction of ground-water (and, where present,

contaminant) flow. These maps are frequently used by municipalities and developers to evaluate ground-water conditions

for water supply and resource-protection requirements.

Figure 4. Concentrations of total volatile organic compounds in water from wells and springs in

Chester County, 1980-96.

Figure 5. U.S. Geological Survey personnel collecting benthic

invertebrates from Pickering Creek near Phoenixville, Pa.

Figure 6. Brillouin’s Diversity Index of benthic macroinvertebrates for Valley Creek

at Atglen, Pa., 1971-96.
INTERPRETIVE STUDIES

In addition to data collection and monitoring, the USGS, in

cooperation with Chester County and local entities, has conducted many interpretive studies of the water resources of

Chester County. These studies, which interpret the data collected for the study and long-term-monitoring data, have

evaluated peak flows of streams, ground-water flow and quality, the effects of urbanization on water resources, chemical and

biological quality of streams, and water use.

Computer-based models of peak streamflow are used for

stormwater management and to design reservoirs for flood

control. Models of the West Branch Brandywine Creek developed by the USGS (Sloto, 1982a; 1988a) were used by the

CCWRA to select a site for a new multi-purpose reservoir

(Chambers Lake). Sloto (1985) modeled the peak flows of

Sucker Run and showed that flood-control structures could

reduce 100-year peak discharges for the West Branch Brandywine Creek by 41 percent. Sloto also showed that flood-control

structures in Sucker Run would increase flooding of the Brandywine Creek below its confluence with Sucker Run. A peakflow model of Valley Creek (Sloto, 1988b) was used to illustrate

how increased impervious land area would cause an increase

in peak streamflows (fig. 8).

Comprehensive evaluations of the ground-water resources

of Chester County were prepared by McGreevy and Sloto

(1977) and by Sloto (1994). Computer models have been developed to simulate ground-water flow in the Pickering Creek

Basin (McGreevy and Sloto, 1980), the Valley Creek Basin

(Sloto, 1990), and the Red Clay Creek Basin (Vogel and Reif,

1993). Sloto (1994, p. 53) used the model of the Pickering Creek

Basin to illustrate the effects of increased ground-water withdrawals on streamflow in Pickering Creek.

Three studies have described the effects of urbanization

and land use on water resources or provide background data

for future studies of the effects of urbanization. Sloto (1987)

described the effect of urbanization on the quality and quantity

of surface water and ground water of eastern Chester County.

Senior (1996) studied ground-water quality and its relation to

hydrogeology, land use, and surface-water quality in the Red

Clay Creek Basin. This study showed how nitrate concentration is increasing with time in the base flow of the West Branch

Red Clay Creek. Senior and others (1997) also studied the

hydrogeology and water quality of the West Valley Creek Basin

to provide baseline data prior to additional urbanization. Gaining and losing stream reaches identified in this study are

shown in figure 9. Any contaminants in streamflow in the losing reaches will move downward to the water table.

Several USGS reports describe the biological and chemical

quality of streams. Murphy and others (1982) evaluated the

results of water-quality monitoring in the Brandywine Creek

Basin from 1973 to 1978. Lium (1977) prepared a report on the

limnology of the major streams in Chester County. Moore

(1987) determined benthic-macroinvertebrate indices and discussed water-quality trends for selected streams. Hardy and

others (1995) related land use, concentrations of organochlorine compounds, and trends in benthic-macroinvertebrate

communities in selected streams. These studies show that

changes in the biota can indicate water-quality problems that

cannot be observed on the basis of chemical analyses alone.

Figure 8. Simulated hydrographs of the flow of Valley Creek at the

confluence with the Schuylkill River for storm of December 22-23, 1983,

showing the effects of increased impervious area in the Valley Creek

Basin (from Sloto, 1988b, fig. 18).

Figure 9. Location of losing and gaining stream reaches and dischargemeasurement sites, October 1990, West Valley Creek Basin, Pa.

(modified from Senior and others, 1997).

Figure 7. Areas in Chester County, Pa., where the water table or

potentiometric surface has been mapped by the U.S. Geological

Survey.
NEW STUDIES

Several studies are currently being conducted by the USGS

in cooperation with Chester County. A study of radon in

ground water will provide information on county-wide geographic and geologic distribution of radon and identify those

geologic units that have the highest ground-water radon activities. Low-flow frequency is being computed for stream sites in

Chester County where flow has been measured. A new study

will investigate the effects of land application of treated sewage

effluent (spray irrigation) on ground water and surface water

in New Garden Township. Trends in benthic-macroinvertebrate diversity from 1981 to 1996 will be evaluated to update

earlier studies. A study of the Elk Creek Basin will develop a

water budget, make estimates of ground-water availability, and

describe the chemical quality of ground water. Hydrologic data

collected by the USGS in Chester County is being compiled

into a CD-ROM along with an index to provide greater access

and use of the data by consultants, engineers, researchers, and

planners.

The USGS is cooperating with Chester County and several

state, regional, and Federal agencies in a study of the Christina

River Basin, which includes the White Clay, Red Clay, and

Brandywine Creek Basins (fig. 1) in Chester County, Pa., and

New Castle County, Del. Streamflow, nutrient, and sediment

data will be collected to estimate total loads of nitrate, phosphorus, and sediment from point and nonpoint sources and to

estimate concentrations and loads of these constituents from

various land uses. These data will be used to calibrate a watershed model of the basin for these constituents. The watershed

model will simulate the hydrodynamics, chemical reactions,

and sediment transport in the stream and the delivery of nonpoint-source contaminants to the stream. This study will

provide the basis for a Christina River Basin watershed-management plan to protect sources of water supply and preserve

ecological resources.

APPLICATION OF HYDROLOGIC DATA AND RESULTS OF

STUDIES TO COMPREHENSIVE PLANNING AND LAND-USE

MANAGEMENT

The data, results, and products developed by the USGS in

the cooperative water-resources investigation program with

Chester County have created a base of water-resources knowledge that is being increasingly incorporated into land-use

planning and management at all levels of government. Many

USGS documents are cited in municipal ordinances as authoritative sources of information and resource data. USGS data and

products are frequently used by watershed associations in

watershed-management studies and activities. Water-resources

management goals and policies for Chester County were

defined in “Landscapes,” the County’s comprehensive planning policy document. These policies are being carried forward

in a county-wide water-resources management and water-supply planning effort, which will be based on the scientific

foundation of nearly 40 years of water-resources data and

understanding developed through the cooperative program.

This new plan will provide County and local land planners and

municipal decisionmakers with the water-resources data and

understanding necessary to make informed land-use management decisions to accommodate growth while preserving the

integrity of Chester County’s natural resources.

REPORTS PREPARED BY THE U.S. GEOLOGICAL SURVEY

in cooperation with the CHESTER COUNTY

WATER RESOURCES AUTHORITY

Aichele, S.S., and Wood, C.R., 1996, Altitude and configuration of the potentiometric surface in

the crystalline and metasedimentary rocks in East Brandywine, Upper Uwchlan, and

Uwchlan Townships and parts of Caln, East Caln, and West Whiteland Townships, Chester County, Pennsylvania, April 1993 through June 1994: U.S. Geological Survey OpenFile Report 96-338, 1 plate, scale 1:24,000.

Garges, J.A., 1986, Ground-water levels in lower Paleozoic and Precambrian crystalline rocks,

southeastern Chester County, Pennsylvania, July and August 1986: U.S. Geological Survey Water Resources Investigations Report 86-4352, 1 plate, scale 1:24,000.

_____1988, Ground-water levels in lower Paleozoic and Precambrian crystalline rocks of East

Bradford and West Bradford Townships, Chester County, Pennsylvania, July and August

1987: U.S. Geological Survey Water Resources Investigations Report 88-4052, 1 plate,

scale 1:24,000.

Hardy, M.A., Wetzel, K.L., and Moore C.R., 1995, Land use, organochlorine compound concentrations, and trends in benthic invertebrate communities in selected stream basins in

Chester County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations

Report 94-4060, 78 p.

Lium, B.W., 1976, Limnological data for the major streams in Chester County, Pennsylvania:

U.S. Geological Survey Open-File Report, 219 p.

_____1977, Limnological studies of the major streams in Chester County, Pennsylvania:

U.S. Geological Survey Open-File Report 77-462, 37 p.

McGovern, J.E., Bossert, April, and Wettstein, W.C., 1996, Altitude and configuration of the

potentiometric surface in the crystalline and metasedimentary rocks in Valley and West

Brandywine Townships, Chester County, Pennsylvania, May 1992 through August 1993:

U.S. Geological Survey Open-File Report 96-339, 1 plate, scale 1:24,000.

McGreevy, L.J., 1974, Seepage study of streams crossing Chester Valley, Chester County,

Pennsylvania: U.S. Geological Survey Open-File Report, 12 p.

McGreevy, L.J., and Sloto, R.A., 1976, Selected hydrologic data, Chester County,

Pennsylvania: U.S. Geological Survey Open-File Report, 138 p.

_____1977, Ground-water resources of Chester County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations Report 77-67, 76 p.

_____1980, Development of a digital model of ground-water flow in deeply weathered crystalline rock, Chester County, Pennsylvania: U.S. Geological Survey Water-Resources

Investigations Report 80-2, 42 p.

McManus, C.B., 1990, Altitude and configuration of the potentiometric surface in the Triassic

sandstones and shales, northern Chester County, Pennsylvania, October 1989 through

March 1990: U.S. Geological Survey Water Resources Investigations Report 90-4114,

1 plate, scale 1:24,000.

_____1992, Altitude and configuration of the potentiometric surface in the crystalline and

metasedimentary rocks, northern Chester County, Pennsylvania, May through October

1990: U.S. Geological Survey Water Resources Investigations Report 91-4182, 1 plate,

scale 1:24,000.

McManus, B.C., and Sloto, R.A., 1994, Altitude and configuration of the potentiometric surface,

May and June 1993, and change in water level 1983-93, in the carbonate rocks in part of

East Whiteland and Charlestown Townships, Chester County, Pennsylvania:

U.S. Geological Survey Open-File Report 93-659, 1 plate, scale 1:24,000.

Moore, C.R., 1987, Determination of benthic-invertebrate indices and water-quality trends of

selected streams in Chester County, Pennsylvania: U.S. Geological Survey WaterResources Investigations Report 85-4177, 62 p.

_____1989, Physical, chemical, and biological data for selected streams in Chester County,

Pennsylvania, 1969-80: U.S. Geological Survey Open-File Report 85-686, 289 p.

Murphy, J.J., Ritter, J.R., Brown, A.E., and Chiarella, J.P., 1982, An evaluation of water-quality

monitoring in the Brandywine Creek Basin, Pennsylvania, 1973-78: U.S. Geological Survey Open-File Report 81-1115, 28 p.

Schreffler, C.L., 1997, Drought-trigger ground-water levels and analysis of historical water-level

trends in Chester County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations Report 97-4113, 6 p.

Senior, L.A., 1996, Ground-water quality and its relation to hydrogeology, land use, and surfacewater quality in the Red Clay Creek Basin, Piedmont Physiographic province, Pennsylvania and Delaware: U.S. Geological Survey Water-Resources Investigations

Report 96-4288, 122 p.

Senior, L.A., and Garges, J.A., 1989, Altitude and configuration of the potentiometric surface in

the Triassic sandstones and shales, northeastern Chester County, Pennsylvania, September 1987 through January 1988: U.S. Geological Survey Water Resources Investigations

Report 89-4043, 1 plate, scale 1:24,000.

Senior, L.A., Sloto, R.A., and Reif, A.G., 1997, Geohydrology and water quality, West Valley

Creek basin, Chester County, Pennsylvania: U.S. Geological Survey Water-Resources

Investigations Report 94-4137, 160 p.
REPORTS PREPARED BY THE U.S. GEOLOGICAL SURVEY

in cooperation with the CHESTER COUNTY

WATER RESOURCES AUTHORITY—CONTINUED

Sloto, R.A., 1982a, A stormwater management model for the West Branch Brandywine Creek,

Chester County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations

Report 81-73, 34 p.

_____1982b, Digital computer simulation of proposed flood-control structures in the West

Branch Brandywine Creek basin, Chester County, Pennsylvania [abstract]: EOS, Transactions of the American Geophysical Union, v. 63, no. 18, p. 320.

_____1984, Water-table contour map of the carbonate rocks of eastern Chester County,

Pennsylvania: U.S. Geological Survey Open-File Report 84-235, 1 plate, scale 1:24,000.

_____1985, Effects of flood controls proposed for the Sucker Run basin, Chester County,

Pennsylvania: Chester County Water-Resources Report 1, 30 p.

_____1987, Effect of urbanization on the water resources of eastern Chester County,

Pennsylvania: U.S. Geological Survey Water-Resources Investigations Report 87-4098,

131 p.

_____1988a, Effects of flood controls proposed for the West Branch Brandywine Creek, Chester County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations

Report 86-4054, 28 p.

_____1988b, Effect of urbanization on storm-runoff volume and peak discharge of Valley Creek,

eastern Chester County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations Report 87-4196, 32 p.

_____1989, Selected ground-water data, Chester County, Pennsylvania: U.S. Geological Survey Open-File Report 87-217, 198 p.

_____1990, Geohydrology and simulation of ground-water flow in the carbonate rocks of the

Valley Creek basin, eastern Chester County, Pennsylvania: U.S. Geological Survey

Water-Resources Investigations Report 89-4169, 60 p.

_____1991, Drought management based on water-level data, Chester County, Pennsylvania

[abstract]: Proceedings 27th Annual Conference on Water Management of River Systems and Symposium on Resource Development of the Lower Mississippi River, American

Water Resources Association, p. 439-440.

_____1994, Geology, hydrology, and ground-water quality of Chester County, Pennsylvania:

Chester County Water Resources Authority Water Resources Report 2, 127 p.

Speight, D.W., 1985, Ground-water levels in the Cockeysville marble of southern Chester

County, Pennsylvania, 1983-84: U.S. Geological Survey Water Resources Investigations

Report 85-4341, 1 plate, scale 1:24,000.

Vogel, K.L., Miller, W.E., and McManus, B.C., 1991, Altitude and configuration of the water-level

surface in the Lower Paleozoic and Precambrian crystalline rocks of the Red Clay Creek

basin, Chester County, Pennsylvania, and New Castle County, Delaware, June through

October 1989 and March 1990: U.S. Geological Survey Water Resources Investigations

Report 91-4004, 1 plate, scale 1:24,000.

Vogel, K.L., and Reif, A.G., 1993, Geohydrology and simulation of ground-water flow in the Red

Clay Creek Basin, Chester County, Pennsylvania, and New Castle County, Delaware:

U.S. Geological Survey Water-Resources Investigations Report 93-4055, 111 p.

Wettstein, W.C., and Wood, C.R., 1996, Altitude and configuration of the potentiometric surface

in the crystalline and metasedimentary rocks in Sadsbury, West Caln, and West Sadsbury

Townships, Chester County, Pennsylvania, April 1993 through August 1994:

U.S. Geological Survey Open-File Report 96-340, 1 plate, scale 1:24,000.

Wood, C.R., 1984, Ground-water levels in the carbonate rocks of central Chester County, Pennsylvania, May 18 to June 15, 1984: U.S. Geological Survey Open-File Report 84-715,

1 plate, scale 1:24,000.

_____1985, Ground-water levels in the lower Paleozoic carbonate rocks of western Chester Valley, Chester County, Pennsylvania, November, 1984: U.S. Geological Survey Water

Resources Investigations Report 85-4224, 1 plate, scale 1:24,000.

Wood, C.R., Wettstein, W.C., Aichele, S.S., Joyce, James, and Schneider, F.M., 1996, Altitude

and configuration of the potentiometric surface in the crystalline and metasedimentary

rocks in Birmingham, Newlin, Pennsbury, and Pocopson Townships and parts of East Marlborough and Kennett Townships, Chester County, Pennsylvania, June 1994 through

November 1995: U.S. Geological Survey Open-File Report 96-336, 1 plate, scale

1:24,000.

REPORTS PREPARED BY THE U.S. GEOLOGICAL SURVEY

in cooperation with the U.S. ENVIRONMENTAL

PROTECTION AGENCY

McManus, C.B., and Sloto, R.A., 1996, Altitude and configuration of the potentiometric surface,

December 6, 1994, in the carbonate rocks in part of East Whiteland and Charlestown

Townships, Chester County, Pennsylvania: U.S. Geological Survey Open-File Report 96-

367, 1 plate, scale 1:24,000

Sloto, R.A., 1997, Hydrogeologic investigation of the Malvern TCE Superfund Site, Chester

County, Pennsylvania: U.S. Geological Survey Water-Resources Investigations

Report 96-4286, 124 p.

Charles R. Wood—1998

For additional information on

Chester County Water Resources Authority

programs and activities, contact:

Janet L. Bowers, P.G.

Executive Director

Chester County Water Resources Authority

Government Services Center

Suite 270

601 Westtown Road

West Chester, PA 19382-4537

(610) 344-5400

Fax: (610) 344-5401

For information on USGS programs and

activities in Pennsylvania, please visit our Web

site at

http://pa.water.usgs.gov/

or contact:

District Chief

USGS, WRD

840 Market Street

Lemoyne, PA 17043-1584

(717) 730-6900

Fax: (717) 730-6997

Email: dc_pa@usgs.gov

Additional earth science information can be

obtained by accessing the USGS Home Page at

http://www.usgs.gov/

For information on all USGS products and

services, contact:

1-800-USA-MAPS

Fax: (703) 648-5548

Email: esicmail@usgs.gov