FARMERS and landowners are working with agencies to reduce flooding on Dartmoor.
The Westcountry Rivers Trust (WRT) and the Environment Agency (EA) are advising mostly upland farmers on land and animal management in a series of micro-measures. The EA is funding natural flood management works delivered by the trust.
The measures are part of two wider projects called the Dartmoor Headwaters and Upstream Thinking. The latter involves post-covid funding as green recovery.
Both involve natural and partly natural methods of reducing the surface flow during heavy rain which can escalate and become a torrent and affect villages down stream.
Rafael Pompa, land adviser with the WRT, is closely involved in helping farmers.
He said: ‘These measures might not look much, but cumulatively they are having a big effect. The idea is to slow the flow off the moorland and increase the retention of rainwater into the ground. So, we try to increase the amount of water the ground soaks up.
‘We are also working with farmers to reduce pollution of run-off water reaching rivers by helping them with farm infrastructure to separate dirty from fresh water. This has included providing roofing over farmyards to stop dirty water being washed into the fields.’
It also helps with protecting the edge of small upland flooded areas with rocks to stop erosion by water and slowing the flow and increasing the chance of it slowly soaking into the ground before reaching already swollen streams.
This method also reduces the amount of sediments in flood water, which block drains, making flooding worse.
He added: ‘Flood water can also bring nutrient rich water and sediments downstream which is bad for the health of water. It increases algal growth on stream surfaces, trapping wildlife and reducing oxygen below the surface.’
Another micro-measure is building low level walls at right angles to the traditional upland dry stone walls. The walls allow flood water to drain off fields, which is a good feature, but this creates fast flowing drainage alongside the wall in ditches.
Rafael said: ‘The new lower walls slow this flow, reduce flooding down stream and have helped promote the colonisation of the ditches and walls by vegetation. We also slow the flow of sudden flood water by adding small granite boulders. In both cases the growth encourages biodiversity.’
He said farmers can also plant various grasses for a healthier cattle diet and increase root depth to reduce flood damage. Rotational grazing also reduces soil compaction by cattle.
Rafael said: ‘This, the charity’s Rapid Response Catchment project considers micro-catchment flood risks and mitigation in the region, while empowering residents and landowners in increasing their resilience to floods.’