National Trust reveals ‘leaky dams’ plan for Holcombe Moor

The programme is part of a two-year project between the National Trust and United Utilities, taking place across the Stubbins Estate in the Upper Irwell catchment, which lies directly below Holcombe Moor.

The project aims to slow the flow of rainwater from the hills into the River Irwell and its tributaries using natural flood management techniques.

Nik Taylor, area ranger at the National Trust, said: “The leaky dams form part of our wider work to mitigate climate change, reduce flooding, support farming and improve biodiversity and habitats across our moorland, farmland and woodland areas.

“Working in partnership with United Utilities, we’re sharing time and knowledge to make a difference for nature, downstream communities, businesses, tenant farmers and commoners.”

Four types of ‘leaky dams’ will be installed across moorland, farmland, and woodland areas to either hold back or slow rainwater.

This will reduce the volume flowing into the River Irwell and the sewer network during periods of heavy rainfall.

The dams are designed to encourage rainwater to soak into the ground or temporarily pool upstream.

This helps reduce the risk of flash flooding in nearby communities and eases pressure on sewer systems during storms.

The project also promises wider environmental benefits, including increased carbon capture, improved biodiversity and upland habitats, and greater resilience to wildfires.

Supported by the Environment Agency and Natural England, the scheme builds on earlier peatland restoration and flood management work at Holcombe Moor.

It is funded by United Utilities as part of its £280 million Rainwater Management Programme.

The programme combines nature-based solutions and smart engineering to create climate-resilient environments and reduce strain on sewage systems.

Marianne Ridley, insights manager for rainwater management at United Utilities, said: “These leaky dams will hold rainwater in the uplands for longer, allowing woodland and moorland to function more naturally like a sponge.

“Vitally, for us, slowing the flow of water reduces flood risk to the communities below and improves the resilience of United Utilities’ operational network.

“This project is a great example of the many benefits of working together and taking a whole-catchment approach.

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“We are excited to see how this will shape and drive future projects in upland catchments.”

Monitoring will be carried out before and after installation to assess the effectiveness of the dams.

The National Trust and United Utilities will be working with the University of Liverpool and the University of Manchester to track environmental changes over time.