New natural flood management project to protect communities at risk of flooding

A new natural flood management (NFM) project in the Whitewell Brook Catchment, near Rossendale has secured a share of the Environment Agency's £25m National NFM Programmes funding, providing vital investment to help alleviate flood risk in the area.

The project, led by Mersey Forest through Community Forest Trust, will receive over £198,000 through the national programme and will be used to help two communities at risk of flooding within the Whitewell Brook catchment – Forest Holme and Lumb, plus Whitewell and Piercy. In total an estimated 77 residential properties and 42 business properties in the area, that are at risk of flooding, will benefit.

The project aims to reduce local flood risk to these communities using NFM techniques which protect, restore and mimic natural river functions, slowing peak flows and temporarily storing flood water in the landscape, resulting in reduced flooding in communities at risk downstream.

The project will focus on introducing NFM interventions on three farms on both sides of the Whitewell Brook valley and aims to deliver:

• 10 clay core earth bunds to temporarily store water behind, slowly releasing stored water over a 24-48hr period following heavy rainfall. These have the added benefit of increasing the extent of wet grassland/wetland habitat which should be beneficial to many species including wading birds.
• 23 living leaky barriers in watercourses to interrupt and slow peak flows and temporarily store water. These use locally sourced timber wood to create the equivalent of a natural dam to interrupt and slow peak flows and temporarily store water.  The addition of woody material to watercourses also provides excellent habitat for fish and invertebrates and increases diversity of flows which is beneficial to many species.
• One storage pond and seven scrapes (shallow depressions excavated to collect and hold water), providing temporary storage and improved aquatic/wetland habitat.
• Enhancement to wet grassland in four different areas by encouraging water out of ditches and onto existing low-lying wet areas where it can infiltrate into the soil.

The Mersey Forest will be working with Professor Neil Macdonald from the University of Liverpool's Geography Department to monitor the success of the NFM interventions. Monitoring equipment has already been installed earlier this year to collect baseline data prior to the NFM interventions being constructed. This will allow a comparison of the catchment's hydrological response to rainfall before and after NFM is installed, allowing us to better quantify the effect the interventions have had on the catchment.

Rob Dyer, Natural Flood Management Manager at The Mersey Forest, said: "We're extremely thankful to the three local landowners who approached The Mersey Forest with a desire to help build flood resilience for the communities at risk downstream of their land. Without them, this project would not be possible. We hope this project demonstrates what can be achieved with minimal effect to the landowner's activities and leads to further interest in NFM from other landowners in the wider Upper Irwell catchment. We're also immensely grateful to the Environment Agency's NFM Programme Team for their funding, which has been instrumental in bringing these proposals to life.

"With the increasing effects of climate change on our communities, we are committed to work alongside local landowners, residents and partners to deliver more NFM across the area to maximise flood risk mitigation by working with natural processes."