Simulation of the hydrological impacts of climate change on a restored floodplain

Thirty UK Climate Projections 2009 (UKCP09) scenarios are simulated using a MIKE SHE/MIKE 11 model of a restored floodplain in eastern England. Annual precipitation exhibits uncertainty in direction of change. Extreme changes (10 and 90% probability) range between -27 and +30%. The central probability projects small declines (<-4%). Wetter winters and drier summers predominate. Potential evapotranspiration increases for most scenarios (annual range of change: -41 to +2%). Declines in mean discharge predominate (range: -41 to +25%). Reductions of 11-17% are projected for the central probability. High and low flows, and the frequency of bankfull discharge exceedence reduce in most cases. Duration of winter high floodplain water tables declines. Summer water tables are on average at least 0.11 and 0.18 m lower for the 2050s and 2080s, respectively. Flood extent declines in most scenarios. Drier conditions will likely induce ecological responses including impacts on floodplain vegetation.