The importance of peak attenuation for flood risk management, exemplified on the Meuse River, the Netherlands

Peak attenuation results in a gradual decrease of the peak discharge when a flood propagates in downstream direction. Peak attenuation occurs along all rivers, but is not equally strong on all rivers. The rate of peak attenuation depends on the river geometry, such as river slope, floodplain width and available storage areas (floodplain, wetlands and lakes). Along many rivers worldwide, measures have been taken that decrease peak attenuation and hence resulted in higher flood water levels and increased flood risk downstream. This paper shows the importance of considering peak attenuation in flood risk management. It also shows that construction of embankments may, contrary to what generally is expected, increase peak attenuation, but that this strongly depends on the height of the flood defences in combination with the discharges that pose the greatest threat to areas downstream. This is exemplified using the Meuse River in the Netherlands as a case study.