Flood risk regulation
Flooding costs an estimated £1.3—2.2 billion per year (Defra 2009) and has a significant impact on human health and well-being. As the magnitude and frequency of flood events is predicted to increase, with more seasonal extremes of rainfall due to climate change, natural buffers such as peatlands need to be protected.
Since the water table is usually close to the surface in peatlands, there is often little room to store extra water when it rains. As uplands are areas of high rainfall and generally rapid runoff (with flashy hydrographs in which rainwater flowing downhill relatively quickly), they are significantly linked to downstream flood events.
If we can slow the rate at which water runs off the hills, by re-vegetating bare peat and reducing erosion, this may reduce the quantities of water and loose sediment (which settles in reservoirs, reducing their capacity to store water) moving downstream at any one time.
At the moment we know we can achieve this at a small, local level by re-vegetating and gully blocking but the impact this has downstream, on a larger catchment scale, is still uncertain.
Images left to right: Investigating relationships between precipitation, over-land flow, run-off discharge (with V-notch weirs) and water table height across different landcovers (e.g. intact, restored and bare peat) in relation to downstream flood events.
One of our current research aims is to investigate how moorland restoration works can contribute to reducing local flood risk. This is the primary objective of the following projects: