Ecological effects of water retention in the river Rhine valley: A review assisting future retention basin classification

This review paper summarizes the ecological effects of the use of floodplains and flood retention basins to control river flow in the River Rhine (Rhein) valley. Early River Rhine regulation strategies including channel straightening are assessed. The subsequent disappearance of alluvial hardwood forests has been highlighted as the major disadvantage. The response of trees to more recent strategies such as ecological flooding is also assessed. Water quality and habitat improvements due to these ecological control techniques are identified as effective. The development of flood retention basin classification methodologies and floodplain management decision support systems particularly for the upper River Rhine Valley is recommended. The purpose is to aid communication among engineers and scientists, and to promote a holistic, integrated and international water resources management strategy, which would be relevant not only for the River Rhine valley but also for similar rivers in a temperate climate