USING MACROINVERTEBRATE COMMUNITY ASSEMBLAGES TO
ASSESS WATER QUALITY
Kevin M. Gill, Carly Nagle, Hannah Devine, and Stephanie Ligouri (Jason
Hamilton), Department of Environmental Studies & Sciences, Ithaca College
The Stroud Water Research Center’s Schuylkill River Project is a systematic characterization of
individual tributaries in the Schuylkill River Basin. Within the 1900 square-mile basin nineteen
tributaries have been under long-term study since 1996. This ongoing study aims to provide
annual information on the quality of each site and to identify long-term trends in water
quality. For all 19 tributaries five samples were collected from a single riffle using a modified
Hess sampler. The Hess device collected macroinvertebrates in a 500 micrometer mesh net
by disturbing the substrate in a 0.088 m2 sample area. All macroinvertebrates found in each
sample were identified to family and were used to calculate ten different diversity indices.
The scores of the ten indices were then used to form a composite score known as the
Macroinvertebrate Aggregated Index for Streams (MAIS) score. The results from the summer
of 2010 indicate that five tributaries had MAIS scores indicative of good water quality, nine
fell under “fair” designation, and five were of “poor” quality
according to the standard of the MAIS composite scoring system.
These data are being used by the Pennsylvania Department of
Environmental Protection to evaluate stream water quality and
to allocate the resources to protect high quality sites and to
remediate those of poor quality. The sites designated as fair
remain untouched until they score high enough for protection
or low enough for remediation.