When you look at the site, you would never imagine that such a small, innocuous valley could make such a huge contribution to reducing flooding locally, and to biodiversity. But witnessing just one of these projects in action makes you realise just how easy it would be to capture and store millions more litres of water in our countryside, in flood storage that would benefit people and wildlife.
When we started this project, we thought that the majority of the water flowing into the site would be flood overflow from an adjacent stream. What has happened instead is that it has filled up rapidly from rainfall running off the surrounding grassland slopes. This is particularly interesting. In a natural meadow like this, it is widely accepted that the rough grassland will slow
down rainfall enough to enable most of it to filter into the soil and away into aquifers rather than flowing over the land surface. However, the intensity of the rainfall meant that instead, there was very obviously a lot of overland surface water flooding filling up the new washland, way before any actual river flooding took place. The soil on the site is some of the best I’ve seen, so it is not soil compaction creating this flood run off, it is simply the volume of water falling onto the slope in a short space of time.
So our new washland is helping to store both river and ‘land’ flooding, and in doing so is creating some really nice restored wetland habitat. Seeing so much water appear in the washland overnight was fantastic. I can’t wait to see what wildlife shows up next spring.