Energy crops on floodplains – flood risk or benefit?

Under the Renewable Energy Strategy the UK aims to achieve 15% of its energy needs from renewable sources by 2020, with 30% of the renewable energy target coming from biomass. Farmers are being encouraged through the Energy Crops Scheme to plant energy crops such as Miscanthus or Willow in suitable locations. However, there is little understanding of the impacts that dense plantings of these crops might have on flood dynamics and flood risk, This has often led to some applications for the crops being, potentially unnecessarily, refused on a precautionary basis. A short-term project was carried out to help bridge this gap in scientific knowledge. Two case study floodplains were selected, namely the River Severn at Uckinghall (Tewkesbury) and the River Isle at Ashford Mill (Ilminster). Additionally, a theoretical model was designed to help define scenarios with the biggest impacts, without introducing local subtleties specific to each case study. This paper describes the approach and provides outputs of the modelled scenarios, including changes to river and floodplain flows, flood depths, velocities, and the overall likely impact of the energy crops upstream and downstream. The conclusions discuss how the findings inform new guidance and practice regarding energy crops on floodplains, and how such a change can inform national policy in this area.