Slow the Flow – Somerset Rivers Authority’s Natural Flood Management Project

“There isn’t one solution to flooding. We need a range of solutions,” says Councillor John Osman, chair of the Somerset Rivers Authority in the UK.

The Somerset Rivers Authority has recently earmarked £550,000 for natural flood management activities, under their “Slow the Flow” project. Farmers and landowners in the county are being encouraged to carry out a range of natural flood management solutions such as tree and hedge planting, and building woody dams, soil bunds or attenuation ponds.

Councillor John Osman said: “This is something which is fairly low-cost, it’s good for the environment and it will play a critical part if we can replicate this kind of scheme around the county.

“If we can slow the flow of water then hopefully we can prevent so many problems happening in the future.”

Somerset Levels Floods, 2013 to 2014

The Somerset Rivers Authority (SRA) was launched on January 31, 2015, to play a key role in flood protection Somerset, the county in south west England that was devastated by flooding during the winter of 2013 to 2014.

During December 2013 and January 2014 heavy rainfall led to extensive flooding on the Somerset Levels and Moors. Some areas were under water for several weeks. An Economic Impact Assessment produced for the SRA shows that the winter floods cost Somerset up to £147.5 million. According to the SRA, there was 150km2 of flooding, with 81 road closures, and at least 165 homes, 50 businesses and 12 farmsteads flooded inside.

Somerset’s 20-Year Flood Action Plan

The SRA’s purpose is to create better flood protection and resilience against further flooding by joint planning and delivery. Since its launch, the SRA has been involved in an impressive range of flood mitigation projects as part of Somerset’s 20-Year Flood Action Plan.

Such projects include the dredging of the Parret and Tone rivers; a road-raising scheme at Muchelney, a village cut off by flood waters for almost a month in 2014; and the proposed widening of the Sowy River and desilting of King’s Sedgemoor Drain.

Slow the Flow

But as Councillor John Osman says, “there isn’t one solution to flooding” and flood management isn’t just about big engineering projects.

That’s why the SRA are encouraging natural flood management solutions, under their “Slow the Flow” project.

Slow the Flow is all about natural flood management. It includes a wide range of flood management schemes such as water meadow restoration, attenuation ponds, soil bunds, rainwater harvesting and tree and hedge planting.

The aim of the project is to look at catchments as a whole, in particular “flow pathways” – places where water is known to run during times of heavy rainfall – and find suitable points or locations where the water can be slowed or held back.

To encourage participation in the Slow the Flow project, grants are being offered to farmers and landowners for projects that will slow the flow of water and reduce the risks of flooding across Somerset. Somerset Rivers Authority has earmarked £550,000 for natural flood management activities that will benefit roads, villages and towns – and improve the environment for people and wildlife.

6,000 Trees Planted

In one example, the SRA is part-funding the creation of 10 acres of new woodland of thousands of trees, in the catchment of the River Isle, which feeds into the Parrett.

A fairly steep section of land on Ewen Cameron’s estate at Dillington near Ilminster will no longer be used for grazing. Instead, it’s been planted with a mix of 6,000 native broadleaf trees, set about 6 feet apart, to provide denser cover than usual and slow the flow of water from slope to valley stream.

Planting new woodland: John Osman, Chairman of Somerset Rivers Authority, with Lord Cameron, owner of the Dillington estate.
Planting new woodland: John Osman, Chairman of Somerset Rivers Authority, with Lord Cameron, owner of the Dillington estate.

Ewen Cameron said: “This is part of the catchment of the River Isle, it’s a small little bowl that runs into the River Isle, and clearly if you get a lot of rain, trees are far better at stopping the flow of water rushing down into the stream, rushing into the River Isle and into the Parrett, causing the flooding we’ve had recently, so if we can plant the trees, it slows the water down, and that’s what we are trying to achieve.”

The scheme is mostly being funded by the Forestry Commission, under a new Countryside Stewardship scheme, but the SRA has contributed nine per cent of the cost so as to maximise the flood reduction benefits.

Ben Thorne, senior farm conservation officer with Farming and Wildlife Advisory Group, South West (FWAG SW), and leader of the SRA’s land management work, said that schemes did not have to be large-scale: “We’re looking for planting in strategic locations, that can make a difference: like steep slopes, like corners, next to roads, next to rivers. It has to be the right type of planting, in the right place.”

View over new plantation on Dillington estate
View over new plantation on Dillington estate

Ponds and Leaky Dams

Another example of Slow the Flow in action is the renovation of disused ponds and the introduction of “leaky dams” or wood debris dams.

The SRA is currently funding work on three ponds and a series of dams in the Meeds Valley on Abbey Farm in Montacute near Yeovil, Somerset. The ponds will be dug out in order to hold water, and “slow the flow”.

One of the ponds is an ancient stewpond from Montacute Priory (founded c.1100), that was almost completely silted-up. The other two may once have been 18th-century ponds for washing flax. These too were almost defunct. They are being dug out again primarily to hold water, but also for wildlife.

Pond restored at Abbey Farm, above Montacute. An old Montacute House estate map of 1778 shows this as the site of a flax-washing pond.
Pond restored at Abbey Farm, above Montacute. An old Montacute House estate map of 1778 shows this as the site of a flax-washing pond.

Also as part of the project, a ditch has been cleared out for the first time in 40 years and new dams are being created, some with I-beams, sleepers and boards, to allow water levels to be controlled, whilst other “woody debris dams” will be built using local logs.

Montacute cleared out ditch looking uphill
Montacute ditch clearing

Over 60 woody debris dams are being proposed in Somerset to help slow the flow of water from catchment areas into rivers.

A new dam built near Chillington in South Somerset.
A new dam built near Chillington in South Somerset.

Woody dams are just one example of natural flood management measures being installed across Somerset to help reduce flooding. See the video below to find out more about them.  For more videos on naturla flood management, see the Hills to Levels YouTube channel here.

All photos courtesy of Somerset Rivers Authority. For more about the work of the Somerset Rivers Authority, see their website here.