MONITORING SUBURBAN WATER QUALITY: USING TECHNOLOGY AND FIELD ACTIVITIES TO TEACH SCIENCE AND STEWARDSHIP IN THE DELAWARE RIVER WATERSHED

In 2001, Bryn Mawr College built a retention basin to manage storm-water runoff from a small but heavily paved catchment in the town of Bryn Mawr, Pennsylvania. Water from the basin, Rhoads Pond, drains via Mill Creek to the Schuylkill River, which enters the Delaware River in Philadelphia. By design, Rhoads Pond serves both physical and chemical purposes: it attenuates peak runoff discharges, and it lowers the concentration of anthropogenic contaminants before they enter Mill Creek. Contaminant removal results from nutrient uptake by aquatic and wetland vegetation, algae and diatoms in the pond.

In order to spatially and temporally quantify how well the pond achieves the goals outlined above, we analyzed physical and chemical water properties at six locations along the waterway. In the summer of 2006, students and professors at Bryn Mawr College collaborated to monitor Rhoads Pond and Mill Creek by collecting water samples from each site at least once a week. Through a combination of field and lab analyses, we measured water temperature, dissolved oxygen, conductivity, pH, dissolved ion concentrations and silica content. Benthic macroinvertebrates in the pond and creek were collected, sorted and counted. In addition, six HOBO data-logging microstations were installed to continuously record water temperature and electrical conductivity. A local rain gauge also was installed at the site.

We created a MySQL/PHP-driven online database to compile data from our ongoing monitoring efforts, as well as to provide access to the sparser data collected since the construction of the pond. Housed on the national GEON web server, the database allows for the dynamic creation of graphs of the monitored parameters. Students and teachers from multiple disciplines at Bryn Mawr College and in local schools will be able to use the data and contribute new findings to the database. The Rhoads Pond/Mill Creek project is also being used as a prototype to develop community watershed monitoring tools and K-12 science activities along other local streams in the Delaware River watershed.