Behaving like beavers

By Fran Southgate

Living Landscapes Advisor

As the autumn draws in, and the rain finally starts to fall, we are coming into our busy season for Natural Flood Management. This is the time of year when we do practical work which we hope will help to protect lives and livelihoods from flooding. Sussex Flow Initiative are busily creating seasonal and permanent ponds and other natural water storage features, slowing the flow of water using natural woody dams, planting trees and hedgerows and more.

Effectively, our Sussex Flow Initiative Project Officers are mimicking what our ancient natural ecosystem engineers, the beaver, would have done naturally. As well as helping to reduce flooding, this includes creating fantastic wetland habitat, trapping, storing and regenerating precious soils, and helping to reduce pollution.

I was invited to present at a meeting of the Beaver Advisory Committee for England recently where we heard about the many benefits that beavers can have for people and for the environment. In just a 2.8 hectare plot in the Devon Beaver Trial over the last seven years, beavers have achieved the following :-

• Created 650 m² of new open water habitat
• Increased water storage from 50 m³ to 1000 m³
• Reduced the flood peak by 30%,
• Increased the time it takes for floods to flow through the site from 15 mins to 1 hour
• Enhanced the summer baseflow during drought
• Had three times less sediment leaving the site than entering it
• Trapped 70 kg per m² of sediment - of which 70% entered the site as run off from just a 20 ha piece of land upstream.
• Had five times less phosphate pollution in the water leaving the site
• Increased frogspawn clumps on the site from <;20 to >600
• Stored around 15 tonnes of carbon in 13 ponds

If our work on the Sussex Flow Initiative can achieve even a fraction of these results, then we know we are making a massive positive difference to issues of flooding, drought, pollution, wildlife decline, and many other things. Cumulatively over time, across a large river catchment, these things can all help to make a really big difference.

For more information take a look at these web resources :-

www.sussexflowinitiative.org

www.devonwildlifetrust.org