ABSTRACT
In this paper we present first results of a research project on the artificial groundwater recharge plant in the „Langen Erlen”, a former floodplain area near Basel, Switzerland. There, forested alluvial soils are used for water purification. We investigated the biological purification processes in those soils by measuring soil microbial activity and biomass as indirect parameters of purification performance. In contradiction to ordinary recharge plants where the biofilm on the (sand-) filter surface is very important, we found, that in these forested systems also deeper soil layers are crucial for producing a high groundwater quality. In connection with improved purification performance, we also try to increase the ecological significance of the recharge basins as they are functioning as the last remnants of the former riparian ecosystem. We found that diversified reed vegetation at open sites showed unchanged or even better purification performance than forested sites.
