Flooding, and management, cost the UK £2.2billion per year. Under current economic pressures, flood policy is shifting from entirely flood defences to broader management strategies. This includes “Natural Flood Management” (NFM) which aims to restore the natural functioning of catchments to store water and slow the flow. Examples of NFM, shown in Figure 1, include tree planting, leaky dams and river restoration, along with agricultural land management. These work with hydrological processes, including increasing infiltration of rainfall into the soil, storing water on the floodplain and increasing the flow resistance to flow within the channel to attenuate the flood peak (taking the top of the peak).
However, despite NFM gaining popularity with policy makers and flood action groups, a lack of scientific evidence on its effectiveness and advice about how to go about implementing such an innovative approach are limiting its success.
There are two gaps in current knowledge relating to the effectiveness of NFM. First, at the intervention scale, we do not understand how much hydrological processes are modified by the NFM feature. Second, at the larger sub-catchment and catchment scale, we have limited knowledge of how the effect of interventions combine together and propagate through the river system. The importance of how sub-catchments interact in terms of tributary synchronicity is essential to understand in terms of larger scale scheme design (Pattison et al., 2014).
This project aims to develop specific guidance on how NFM schemes can be designed to optimise and monitor their effectiveness at different spatial scales.
1) Carry out laboratory experiments and field trials to determine how interventions, e.g. leaky dams, can be designed to increase their effectiveness.
2) Develop models to design NFM schemes at the catchment scale to optimise for performance.
3) Optimise methods to work with policy makers and landowners to broaden the implementation of NFM to large catchments.