The effectiveness of a soil bioengineering solution for river bank stabilisation during flood and drought conditions: two case studies from East Anglia

Abstract

The increasing frequency of extreme flow events as a consequence of climate change could potentially impact the stability of lowland clay streams in East Anglia. Some of these rivers act as conveyors of additional water that is pumped downstream to satisfy the growing demand for water in this dry region. To accommodate the additional flows, the river channels have been deepened and straightened and the combined effect is that riverbanks are becoming more unstable. Willow spiling, a bioengineering stabilisation measure, could be an effective and sustainable mitigation option for managing riverbank erosion. There is a growing interest in understanding the performance of such interventions, particularly under changing climatic conditions. Two willow spiling projects were implemented in March 2009 and studied for their biological and geomorphological function during the first year after installation. This study shows that droughts and floods can impact the effectiveness of these measures, but through careful design, implementation and post-project monitoring this method can be effective in withstanding such stresses and protecting riverbanks.