HR: 0830h
AN: H21D-03    [Abstracts]
TI: Impacts of Stormwater Management Measures on E. coli and Enterococci Populations in Stormwater Effluent
AU: * Wildey, R A
EM: rwildey@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AU: Ballestero, T P
EM: tom.ballestero@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AU: Roseen, R M
EM: rroseen@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AU: Houle, J
EM: jjhoule@unh.edu
AF: Center for Stormwater Technology Evaluation and Verification, University of New Hampshire 35 Colovos Road, Durham, NH 03824 United States
AB: In our efforts to improve the quality of runoff entering our streams and waterways, stormwater management measures (or BMPs) are being implemented at a rapid pace. Usually designed to treat one or more specific types of contamination or loading, these measures may have unintended consequences that are not well understood. One issue that has not been fully explored is the potential effect these systems have on microbial contamination of the treated runoff. This study evaluates 11 types of treatment systems and their impact on E. coli and Enterococci contamination. Recent research has demonstrated that near-shore sediment may act as a continuous source of bacterial loading in the overlying waters, rather than bacterial loading being solely a temporal, storm-driven phenomenon. Similarly, stormwater management measures that utilize a soil media for filtration or incorporate a sediment sump may also provide conditions conducive to the incubation of fecal coliforms that can then be released into the environment during runoff events. Following with EPA regulatory guidelines for receiving waters, E. coli and Enterococci are used as surrogates for the presence of other potential disease-causing pathogens typically associated with mammalian and avian enteric bacteria. The stormwater management measures being investigated include: subsurface infiltration, surface sand filter, standard detention pond, bioretention area, hydrodynamic separation, subsurface gravel wetland, street sweeping, and vegetated swale. An adjacent porous parking area and a standard asphalt lot that drains to a tree filter are similarly monitored. Influent is supplied by runoff generated by a 9-acre commuter parking lot at the University of New Hampshire in Durham, NH. This influent is distributed equally to the different treatment devices that operate in parallel. Water quality parameters (DO, pH, specific conductivity, temperature) and flow are continuously monitored upstream from the distribution chamber (influent) and downstream from each device (effluent). Automated samplers are used to collect samples during storm events and grab samples are taken between storm events to evaluate the effect of each device or BMP on bacterial populations. Initial data indicate that influent concentrations of fecal coliforms for this parking area often exceed EPA limits for Class A waterbodies. Several of the treatment units appear to substantially reduce (>90% reduction) bacterial loading, while others appear to increase loading during some storm events (>500% increase). This study is on-going and additional sample events from the Spring of 2005 will also be presented.
UR: http://www.unh.edu/erg/cstev
DE: 1800 HYDROLOGY
DE: 1803 Anthropogenic effects
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2005 Joint Assembly