Restoring gullied peatlands: Natural Flood Risk Management benefits from landscape scale restoration of the 'badlands of Britain'

The dramatic badland landscapes of severely eroded peatlands represent significant degradation of the ecosystems, which when intact, provide a range of regulating ecosystem services including carbon sequestration and runoff regulation. Increasing efforts are being made to restore these landscapes through re-vegetation and gully blocking. Restoration has been driven by the aims of restoring biodiversity and carbon storage but the transformation of hillslopes and channels also has significant impacts on hillslope runoff. This paper reports on a major project from the uplands of the UK which has been studying the generation of hillslope runoff in restored peatlands and the potential to optimise restoration approaches to mitigate downstream flood risk. Peatlands are highly productive of runoff so that these approaches have the potential to deliver multiple benefits including Natural Flood Risk management for headwater communities.

Our work has demonstrated that whilst static storage of water behind gully blocks is one component of the NFM benefit, dynamic storage on hillslopes during storm events is enhanced by increased surface roughness in restored catchments and is the larger component of the overall NFM benefit. Gully blocks with pipes or slots which enable drawdown between storms maximise static storage whilst the planting of sphagnum moss dramatically increases dynamic storage on the hillslopes.

Taken together these data support the potential role of peatland restoration in NFM schemes and suggest that restoration of gully-eroded peatlands can deliver flood protection in headwater communities alongside wider benefits.