Wilder Ouse and Lost Woods leaky dam workshop

Harriet Trueman

Wilder Ouse Officer

Projects working in partnership are a great way to improve our capacity to deliver nature conservation work. Recently, Wilder Ouse and the Lost Woods of the Low Weald and Downs projects came together for a training workshop to build leaky dams. The aim of the day was to knowledge share, work collaboratively and create new habitats for nature. 

Leaky dams, what are they? Imagine a pile of logs, brash and other natural materials placed in a stream or flow path to intercept the flow of the water. This slows down the velocity of water. By reducing this velocity, the dams help lower downstream flood risk during heavy rainfall. This slower flow also holds water in the landscape for longer, helping to reduce drought impacts. From a wildlife perspective, the dams create new habitats for species to benefit from, providing food and shelter through the added wood, decaying materials and pools of water.

Myself and some Sussex Wildlife Trust volunteers ventured out onto Markstakes Common to build a series of leaky dams in the woodland, along with a group of Lost Woods volunteers.

Markstakes Common is ideal for leaky dams, as these natural structures will create a wetter woodland habitat. Wet woodlands are rare and unique in the UK, many have been lost due to clearance and drainage. Their combinations of dead wood and damp conditions provide an array of ecological benefits and ecosystem services, soaking up and storing flood water, filtrating it from pollutants and storing carbon.

The day began with a talk by me, demonstrating the steps needed to create the dams. We discussed how the dams mimic the natural processes that we have lost in our landscape, because we lost our population of British Beaver (Castor fiber) and their incredible function within an environment as eco-engineers.

Working in small groups, ten leaky dams were created, some intercepting flow paths and two acting as barriers in the natural woodland ponds, to hold back water and increase the depths of the ponds.

The day was an absolute success, with volunteers sharing knowledge and experience while problem solving the way the dams are built.

More about Wilder Ouse

The Lost Woods project aims to bring local people together to learn about, explore and care for woods across the Low Weald and Downs. Its work is made possible thanks to The National Lottery Heritage Fund.