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Assessment of stream quality using biological indices at selected sites in the Big Elk and Octoraro Creek basins, Chester County, Pennsylvania, 1981-97

Fact Sheet 115-02

Prepared in cooperation with the Chester County Water Resources Authority
By:
ORCID iD

Links

Introduction

In 1970, the Chester County Water Resources Authority (Pennsylvania) and the U.S. Geological Survey (USGS) established a long-term water-quality network with the goal of assessing the quality of streams in the county and understanding stream changes in response to urbanization using benthic-macroinvertebrate data. This database represents one of the longest continuous water-quality data sets in the country. Benthic macroinvertebrates are aquatic insects, such as mayflies, caddisflies, riffle beetles, and midges, and other invertebrates that live on the stream bottom. Benthic macroin-vertebrates are useful in evaluating stream quality because their habitat preference and low motility cause them to be affected directly by substances that enter the aquatic system. By evaluating the diversity and community structure of benthic-macroinvertebrate populations, a determination of stream quality can be made.

Between 1981 and 1997, the water-quality network consisted of 43 sites in 5 major basins in Chester County—Delaware, Schuylkill, Brandywine, Big Elk and Octoraro, and Red and White Clay. Benthic-macroinvertebrate, water-chemistry, and habitat data were collected each year in October or November during base-flow conditions. Using these data, Reif evaluates the overall water-quality condition of Chester County streams. This Fact Sheet summarizes the key findings from Reif for streams in the Big Elk and Octoraro Creek Basins. These streams include East Branch Big Elk Creek (site 31), West Branch Big Elk Creek (site 32), East Branch Octoraro Creek (site 33) and Valley Creek (site 34). This summary includes an analysis of stream conditions based on benthic-macroinvertebrate samples and an analysis of trends in stream conditions for the 17-year study period.

Suggested Citation

Rief, A.G., 2002, Assessment of stream quality using biological indices at selected sites in the Big Elk and Octoraro Creek basins, Chester County, Pennsylvania, 1981-97: U.S. Geological Survey Fact Sheet 2002–0115, 4 p., https://pubs.er.usgs.gov/publication/fs11502.

ISSN: 2327-6932 (online)

Table of Contents

  • Introduction
  • Study Approach
  • Stream-Quality Designation Criteria
  • Stream-Quality Assessment
  • Trends in Benthic-Macroinvertebrate and Chemical Data
  • Summary
  • References Cited

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Assessment of stream quality using biological indices at selected sites in the Big Elk and Octoraro Creek basins, Chester County, Pennsylvania, 1981-97
Series title:
Fact Sheet
Series number:
115-02
Year Published:
2002
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Pennsylvania Water Science Center
Description:
4 p.
Online Only (Y/N):
Y
Additional Online Files (Y/N):
N