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

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.

Terrain map of White Clay Creek Watershed with well transects and study reaches