The impact of climate change on drinking water supply by riverbank filtration

Abstract

Riverbank filtration (RBF) is a well proven natural treatment, which in many countries is part of a multi-barrier concept in drinking water supply. The induced infiltration of river water into the aquifer produces a significant improvement in river water quality. Riverbank filtration wells are characterized by a high capacity. Based on data from recent years, an integrated approach to assessing the impact of climate change on safe drinking water production by RBF is demonstrated in the Lower Rhine Valley, Germany. Influencing factors on quantitative as well as qualitative aspects were identified. During low river water periods, the capacity of the RBF-wells decreases. In addition the lower discharge within the river is accompanied by a increased concentration of several chemical compounds. Together with higher water temperatures which influence the hydrogeochemical processes during RBF, the changing raw water composition has to be considered for the subsequent technical treatment step. However, our investigations reveal that despite the impact of climate change on RBF, the multi-protective barrier concept, including both natural and technical purification, has proven a reliable method for drinking water production. The sanitation of the Rhine over the last decades was an important step to make RBF more resilient to climate change.