EVALUATING THE EFFECTIVENESS OF REGULATORY STORMWATER MONITORING PROTOCOLS ON GROUNDWATER QUALITY IN URBANIZED KARST REGIONS

As is the case with many urban karst areas, the City of Bowling Green relies on stormwater injection wells to deal with stormwater quantity issues; however, these wells also allow for the direct injection of untreated stormwater runoff into the local karst aquifer. The intent of this study is to determine the effectiveness of current urban stormwater runoff monitoring protocols in capturing the health of the karst aquifer, and the role of stormwater injection wells in the transport of contaminants. Additionally, a critical evaluation of environmental policy and stormwater regulations in Kentucky and elsewhere to determine their ability to address karst landscapes and groundwater was undertaken using a policy critique formula. Preliminary results from three monitoring sites in Bowling Green show elevated levels of fecal coliform bacteria not only during storm events, but during base flow conditions as well. Fecal coliform levels using the Colilert 18-hour test range from 4.1 to 290 colonies per 100mL during base flow, to above 25,000 colonies per 100mL during storm related flow increases. Analysis for other parameters (TDS, cations, anions, oil and grease, etc.) reveal elevated oil and grease levels, from 15mg/L up to 115mg/L during first flush monitoring, as well as nitrate levels up to 300ppm, three times the MCL during both base flow and high flow conditions. In addition to bi-weekly sampling of three output sites for one year, first flush samples were collected from three corresponding inputs over the same time period to provide insight to the effectiveness of higher-resolution stormwater quality monitoring in karst areas to help characterize stormwater contamination. The results provide insight to the effectiveness of higher-resolution stormwater quality monitoring in karst areas to help characterize stormwater contamination, and reveal complex policy challenges at all levels with regard to addressing water quality issues in urbanized karst aquifers.