Schuylkill River Project — Introduction
David Rebuck uses a Hess sampler to collect benthic (bottom-dwelling) macroinvertebrates.
Few river basins have had a longer or stronger connection to socioeconomic, cultural, and industrial development in the United States than the Schuylkill River Basin. This is because the land and water of the Schuylkill Basin have provided many of the resources needed over the last 350 years by colonial, industrial, and even modern Philadelphia, which lies at the downstream end of the basin. When Europeans colonized the Basin in the 1600's, it represented vast forests for lumber, rich soils for farming, miles of streams and rivers for fishing, drinking, transportation and power, and deep beds of anthracite coal as a major energy source. Over time, the forests were completely harvested, thousands of acres were farmed, many tons of coal were mined, and most of the streams were dammed, diverted, pumped, and/or polluted. Concurrent with these activities was the conversion of forest and farmlands to urban and suburban developments.
The Basin today bears little resemblance to the pristine woods found by the first Europeans. However, it is still an invaluable natural resource for the 3 million people that live in the watershed as well as the additional 3 million people from neighboring watersheds that together represent the Philadelphia metropolitan area. For example, forests have regrown to cover about 41% of the basin, and now represent important areas for recreation, wildlife, and potentially silviculture. Agriculture still occupies 40% of the acreage while developed lands represent about 13%. Finally, surface- and groundwater resources in the Basin continues to provide drinking water for more than 3 million people.
The lower reaches of the Schuylkill flow through a mix of agricultural, industrial and urban areas.
This study uses benthic (i.e., bottom-dwelling) macroinvertebrates such as insects, worms, and crayfish that live in the River and its tributaries to assess current water and habitat quality. Benthic macroinvertebrates were chosen as the focus of this monitoring program because they are the most common group of aquatic organisms in water quality assessment programs (Hellawell 1986), they have provided water quality assessment programs with valuable insight for more than 100 years (Cairns and Pratt 1993), and they are now integral in watershed education and outreach programs. Aquatic insects are commonly included in biological monitoring programs that assess water quality in streams and rivers for a number of reasons (Weber 1973, Hawkes 1979, Hellawell 1986).
- Most reaches of a given stream or river ecosystem support relatively diverse (100-200 species) aquatic insect assemblages that include species from several different groups of insects [e.g., Ephemeroptera (mayflies), Trichoptera (caddisflies), Coleoptera (beetles), Diptera (true flies)]. Because each species potentially has different tolerances of environmental change and stress, this diversity can result in hundreds of independent environmental measures that, taken together, provide a relatively sensitive measure of environmental change and stress.
- Their limited mobility and relatively long life spans (a few months to at least a year) make the presence or conspicuous absence of an aquatic insect species at a site a meaningful record of environmental quality during the recent past, including the occurrence of short-term and/or infrequent events that might be missed by assessment programs that rely on periodic water chemistry samples (Weber 1973).
- Aquatic insects form a critical link in the food web, functioning as primary consumers (herbivores and detritivores) of plant and microbial matter and serving as the primary food resource for secondary consumers, especially fish (Weber 1973, Hawkes 1979, Hellawell 1986).
- Their abundance (number of individuals/m2) lends itself to statistical analysis, which can play an integral role in modern water quality monitoring programs.
Schuylkill River as it enters Philadelphia.
As of 2001, macroinvertebrate monitoring protocols had been developed in every state but Hawaii (USEPA 2002). Unfortunately, this has yet to contribute significantly to citizen-based stewardship and advocacy because most streams are rarely sampled, and current data and classifications are often regulatory in nature and therefore not released or are technically complex. Our Schuylkill River project provides the information and tools needed to encourage citizens (children, adolescents, and adults) to interface with local organizations and governments, and with state and federal agencies
This study has three long-term scientific and education goals:
- To establish baseline data that can be used to describe and evaluate water and habitat quality (current and long-term) in the Schuylkill River basin based on aquatic macroinvertebrates collected from numerous locations distributed throughout the basin,
- To make this assessment available to local education outreach and community groups in order to encourage efforts to assess, improve, and/or protect water quality in these streams and rivers, and
- To provide local college students experience in a long-term scientific study, collecting and processing scientific data that will be compared to past data and used in future studies.
It is important to keep in mind that an assessment of current water and habitat quality in the Schuylkill River and its tributaries reflects both past and recent anthropogenic activities. Some scars from past anthropogenic activities are no longer evident while others remain, although time or mitigation may have concealed them or lessened their impact. As a result, caution should be applied in the interpretation of monitoring data when only observations of recent anthropogenic activities are available.