Bacterial Pollution Sourcing and Oceanic Transport on the South Shore of Kaua’i

Abstract

Water quality problems have been plaguing the south shores on the island of Kaua’i in recent years. In the past, issues with water quality have been attributed to agricultural runoff and sedimentation. This study serves to verify past findings by analyzing data provided by water testing completed by volunteers from the Blue Water Task Force established by the Kaua’i Chapter of the Surfrider Foundation. In order to accomplish this goal, we determined the extent of bacterial pollution at each of the sites included in the study and identified individual cases of high bacteria levels. Time series of enterobacteria collected at nine sites along the south shore of Kaua’i show no clear seasonality but rather are marked by seemingly sporadic extreme events. We then coaligned the enterobacteria dataset with precipitation, near-shore currents and wave activity. These datasets were coaligned in order to look for possible correlations. Ultimately, no correlations were found which suggest that the water quality issues that have been observed cannot be accredited to local precipitation or near-shore oceanographic processes. Instead these pollution problems may be driven by irrigation runoff, sewage leaks, or a number of other local drivers. Further research and monitoring will be necessary to continue to provide the public with accurate information regarding the quality of their recreational waters.