Long-Term Research in Environmental Biology: White Clay Creek, Pennsylvania

325 292 Stroud Water Research Center


Stroud Water Research Center and its 800 ha, 3rd-order drainage basin was designated an Experimental Ecological Reserve in 1981 by the National Science Foundation (NSF). This designation, based upon the criteria of site quality, research activities, logistics and financial support, recognized that this field research facility was dedicated to long-term experimental research on an ecosystem this is an outstanding representative of its type.

The East Branch of White Clay Creek is classified by the Commonwealth of Pennsylvania as an Exceptional Value stream and watershed. This the highest classification given and affords the watershed special protection against environmental disturbance of anthropogenic origin.

In 1998, the White Clay Creek experimental watershed, extending from the Stroud Water Research Center north to the headwaters, was designated as a site for long-term research in environmental biology (LTREB). The National Science Foundation LTREB grant to Center scientists recognizes that many important questions in ecology require the acquisition of long time series of data. NSF funds are being use to help maintain an on-going long-term research project examining stream and watershed characteristics associated with a riparian zone restoration/reforestation.

In this LTREB project, the overarching goals involve discerning the time period, most salient features, and final condition of a recovered state. LTREB funding is being used to: (1) maintain existing watershed installations to continue an on-going acquisition of long-term data on White Clay Creek, (2) address the data management needs of the long-term project, including making the data available to the research community, and (3) testing hypotheses concerning long-term variations in stream ecosystem structure and function under stable and/or recovering conditions.

Project Site

The White Clay Creek watershed, like most of the Eastern North American landscape, experienced dramatic anthropogenic disturbances over a relatively short time period (300 years). These are characterized by deforestation for lumber, charcoal, and agriculture, and more recently the broad scale creation of impervious surfaces, introduction of pesticides, increased use of fertilizers, and atmospheric deposition of nitrogen from the combustion of fossil fuels. These landscape and landuse changes have generated conditions that stress stream ecosystems, however, little is known about how streams in the Piedmont physiographic province have responded to these stresses. Even less is known about how streams respond as the disturbed landscapes recover.

When Stroud Water Research Center was established in 1967, the agriculturally dominated watershed contained an upstream riparian forest of 60 to 100 year old trees and downstream meadows subject to cattle grazing. Initially, several long-term sampling reaches on the White Clay Creek were selected, including woodland and meadow reaches. When cattle were removed from the meadow reach adjacent to the laboratory, the riparian zone became colonized by multiflora rose (Rosa multiflora (Thunb)). Over a 23-year period the multiflora rose grew to border the stream in a swath that was 3 meters tall and 5 meters wide. In 1989, the Center began a riparian zone restoration and reforestation project with the goal of reestablishing a contiguous deciduous forest extending through the meadow reach upstream to headwater spring seeps 3 km away. Multiflora rose plants were uprooted and tree seedlings of native species were planted. Between 1988 and 1994, five lateral transects from the uplands to the stream were instrumented with wells, lysimeters, and in-stream piezometers. In 1997, the reforestation project was extended into a meadow downstream of the laboratory.


The tables below list our long-term datasets for White Clay Creek, a subset of which are available for download on HydroShare. If you have trouble accessing the data, please email

Discharge is presented as daily maximum and precipitation as daily total.

Parameter Site Period of Record Frequency
Discharge Watershed boundary 1969-present Continuous
Temperature Meadow, woodland, & springs 1969-present Continuous
Channel Geomorphology Woodland, meadow, tributaries 1972-present Periodic
Solar Radiation Meadow 1969-present Continuous
Precipitation Meadow 1969-present Continuous

Water chemistry is presented as the concentration based on a periodic grab sample.

Parameter Site Period of Record Frequency
Nutrients: NO3, NO2, NH3, PO4 Woodland 1969-present Weekly 1969-1995;monthly 1996 present
Meadow 1996-present Storms once/season
Springs & tributaries 1969-1989 Once to several times annually
Wells & lysimeters 1994-1997 Every other month, 1994-1997; 1998-present periodic
Nutrients: TKN, TP Woodland 1996-present Monthly
Cations: Ca, K, Mg, a, Zn, Cu, Mn, Fe Woodland 1969-present Weekly 1969-1995; monthly 1996-present
Meadow 1996-present Storms once/season
Anions: SO4, Cl Woodland 1969-present Weekly 1969-1995; monthly 1996-present
Meadow 1996-present Storms once/season
pH, alkalinity Woodland 1969-present Weekly 1969-1995; monthly 1996-present
Conductivity Meadow 1994-present Daily & each storm
Wells & lysimeters 1994-1997
Every other month
Dissolved Organic Carbon Meadow 1972-1975 Weekly to monthly & seasonal storms
1978-1994 Daily to weekly & seasonal storms
1995-present Daily & all storms
Wells & lysimeters 1988-1997
Weekly to every other month
Tributaries & springs 1978-present Periodic
Classes of Organic Compounds
(lipids, carbohydrates, phenolics, amino
Meadow, tributaries & springs 1972-present Periodic
Amino acid molecules Meadow 1993-present Seasonal storms
Carbohydrate molecules Meadow, wells, lysimeters, & springs 1994-1996


Weekly & seasonal storms


Humic substances Meadow, wells, lysimeters 1993-1997 Monthly
Humic-Bound Lignin Phenols Meadow, woodland, wells, & lysimeters 1993-1997 Periodic
Biodegradable DOC Meadow 1992-present Weekly
Wells & lysimeters 1994-present Periodic
Pesticides Meadow, woodland & tributaries 1993-1997 Periodic
Seston Woodland 1993-present Weekly
Meadow 1995-present All storms
Parameter Site Period of Record Frequency
Suspended chlorophyll Woodland 2001-2004
Benthic Organic Matter Woodland 1976, 1997 Seasonal
Meadow 1997 Seasonal
Tributaries 1991 Seasonal
Leaf Litter Inputs Woodland 1973-1974 Weekly
Woodland & meadow 1991-2000
Weekly to monthly
Weekly to monthly
Woody Debris Woodland & meadow 1991 Late Autumn
Algal Biomass Woodland & meadow 1973-1975
Daily to weekly
Community Metabolism
(GPP, Respiration, Net Daily Metabolism)
Woodland & meadow 1971-1975
Daily to weekly
Algal Community Composition Woodland 1969-1971 Weekly to monthly
Bacterial Productivity Meadow 1980-81; Seasonally
1985-86; 1989 Seasonally
Bacterial Densities Meadow 1980-81; 1985-86; 1989; 1999-present Seasonally
Bacterial Community Composition Woodland & meadow 1999-present Periodic
Protozoan Community Composition Woodland 1969-1970 Weekly to monthly
Protozoan Densities Meadow & tributary 1983-1985 Monthly
Protozoan Bacterivory Meadow 1984-1985 Seasonally
Meiofauna Densities & Ingestion of Microbes Meadow 1993-1995 Seasonally
Insect Species Richness, Density, Biomass Woodland 1969-72; 1975-76;
1983; 1997-1998; 2003-2004
Monthly to bi-monthly
Meadow 1991-1996 Late Winter
Meadow & woodland 1997-present Late Winter
Insect Emergence Meadow & woodland 1970-present Weekly
Tributaries 1970-1980 Weekly
Insect Genetic Structure Woodland & meadow 1983-1987, 2002 Periodic
Insect Size and/or Fecundity (selected species) Woodland & meadow 1969-1988
Fish Community Composition Woodland & tributary 1972-1973, 1989, 1995, 1997 Periodic


Assistance was provided by National Science Foundation funding under a number of grant awards. Grant awards are noted in the publication listings below.