Runoff management: mitigation measures for disconnecting flow pathways in the Belford Burn catchment to reduce flood risk.

Abstract

Evidence that intensive farming leads to increased runoff rates has been established. Fast, well connected flow paths are clearly contributing to the 'muddy floods' observed at the local scale. By targeting runoff in fields and farm ditches then a significant component of flood generation can potentially be managed at the catchment scale. The Belford Burn (Northumberland, UK) catchment is a small rural catchment with a catchment area of 6 km2. Normal flood defences are not suitable for this catchment as it failed the Environment Agency (EA) cost benefit criteria for support. There was a desire by the local EA Flood Levy Team and the Northumbria Regional Flood Defence Committee at the Environment Agency to deliver an alternative catchment-based solution to the problem. Four different types of mitigation feature have been created in the catchment to reduce flood risk whilst also benefiting water quality and ecology. These measures include bunds disconnecting flow pathways, diversion structures in ditches to spill and store high flows, ‘Beaver dams’ placed within the channel and riparian zone management. Evidence collected from these features, along with construction advice and management issues, has helped to create the first draft of a Runoff Attenuation Features Handbook.