SRA Annual report 2019-20: Natural flood management (NFM) capital grant schemes on the National Trust’s Holnicote estate

Somerset Rivers Authority part-funded seven schemes in 2019-20 to support the National Trust’s major Porlock Vale Riverlands initiative on its 12,000-acre Holnicote estate in West Somerset. The other main funder was the EU’s Interreg 2 Seas programme through a tie-in with Somerset’s Co-Adapt programme. Co-Adapt is aiming to increase local resilience to the water-related effects of climate change: flooding and droughts.

The seven schemes given grants this year follow on from two in 2018-19. They were hedgerow planting at Hurdledown, between Exford and Porlock, and the creation of riparian corridor and habitat through the fencing-off of key areas and the creation of swales and scrapes at Lower Selworthy Farm.

The overarching aim of all these schemes is to slow the flow of water down through the Horner and River Aller catchments, by holding water back and by allowing greater infiltration of surface water into the ground.

Another major benefit is the making of better habitats for wildlife.

The Porlock Vale Riverlands initiative has attracted regional, national and international attention, for reasons including the introduction of beavers and the trial of ‘Stage 0’ techniques of river restoration.

Seven 2019-20 Holnicote schemes part-funded by the SRA

Dunkery Hill, Horner catchment. The road descending from Dunkery Beacon car park to Webber’s Post car park had 30 poorly-functioning cross-drains so, during heavy rain, water was not adequately diverted.

Instead it poured straight down the hill towards Horner Water, which runs close to businesses such as tea-rooms and a popular caravan and camping site.

This scheme, therefore, re-opened the most important drains and ditches. Then three swales and berms were created to catch water running off the road, hold it back, and release it slowly. These three areas also now serve as wet heath and bog habitat.

The National Trust describe this as a ‘little and often’ approach to working with natural processes. SRA funding 40%, Interreg 2 Seas 60%.

Great Wood tree planting, Aller catchment. 2200 trees have been planted below Great Wood in a field which forms a flow path directly onto the A39. The trees will help to reduce the flow of water on to the main road and lower down to the Aller catchment. SRA funding 20%, Interreg 2 Seas 40%, National Trust 20%.

Holt Ball/East Luccombe, headwaters of Aller catchment. 250 metres of double-row cross-slope hedge planting, to increase infiltration and transpiration (the the take-up of water by plants). SRA funding 40%, Interreg 2 Seas 60%.

Whiteman’s Beaver Site, Holt Ball. The SRA funded 20% of the costs of fencing the three-hectare enclosure for two pairs of beavers introduced to Whiteman’s Moor wood.

The beavers’ activities are slowing the flow of water to the lower catchment of the River Aller and improving water quality. They create a mosaic of ponds and wetlands that filters water and reduces silt and other pollutants. Interreg 2 Seas funded 60%, the National Trust 20%.

Horner Farm, Horner, catchment of Horner Water. Pond created to slow the flow and improve the habitat for local wildlife. Banked hedge created to increase infiltration and transpiration to reduce the surface flow of water across the farm.

In January 2018 Horner Farm was let by the National Trust to new tenants whose ambition is to make it “a showcase of positive ecological practice” with natural processes favoured where possible.

The farm featured on the BBC’s Countryfile programme in March 2020. SRA funding 40%, Interreg 2 Seas 60%.

Selworthy, headwaters of Aller catchment. 500m of double-row cross-slope hedge planting at Selworthy to increase infiltration and transpiration. SRA funding 40%, Interreg 2 Seas 60%.

Selworthy Farm, River Aller catchment. A pilot project of ‘Stage 0’ ground works, cross-slope hedgerow planting, tree planting and riparian fencing.

‘Stage 0’ is the name given to an increasingly influential process pioneered on rivers in the US state of Oregon.

In simple terms, it is about restoring rivers so they branch out into a slower, more complex pattern of multiple channels, pools and wetlands.

Where there is the will and the space for this to happen, evidence shows it brings numerous benefits for people and wildlife. It reduces flood risks, improves water quality, and makes bigger and better habitats for more plants and creatures.

“Nature likes a mess,” says Ben Eardley of the National Trust, who is leading the Porlock Vale Riverlands project.

SRA funding 40%, Interreg 2 Seas 60%.