Riverbank Filtration: Induced Infiltration and Groundwater Quality

Abstract

Riverbank filtration relies on the streambed and aquifer matrixes to reduce pathogens under varying conditions of induced infiltration resulting from changes in river stage and flow velocity. The Greater Cincinnati (Ohio) Water Works monitored hydrologic parameters and water quality at its Charles M. Bolton well field during a comprehensive flowpath study. The study determined the frequency of occurrence of high river–stage events from historical data and monitored hydrologic parameters to estimate the potential unit infiltration rate. Giardia, Cryptosporidium , algae, spores, particle counts, and turbidity were also monitored. The project investigated potential pathogen/surrogate breakthrough during several high river–stage and infiltration events. High‐stage events occurred less than 4% of the time. Giardia and Cryptosporidium were not detected in any groundwater samples. Increases in surrogate concentrations were minimal and maintained >3.5‐log reduction. The streambed and aquifer have the ability to buffer water quality effects from major increases in the infiltration rate.