Stopping Sediments in Cheriton

In Cheriton, a rural lane has been funnelling harmful sediment into the local chalk stream. The Watercress and Winterbournes partners have been helping the community to find a solution.

The track known as Dark Lane traces an almost straight line across the Cheriton countryside. Starting at a meeting of unpaved backroads, it slopes downhill for around 220m before joining the busiest route through the village. At its highest point, it's little more than a narrow trail between two hedgerows, but it gradually widens enough for cars to pass through.

It recent years, however, it has become clear that the lane is conveying more than people and vehicles. Sediment hitches a ride in rainwater and ultimately ends up in the nearby chalk stream, putting pressure on this precious habitat. This September, we expanded the local community's solution to the problem as part of the Watercress and Winterbournes Landscape Partnership Scheme.

Visit Dark Lane in wet weather, and it's easy to spot its cargo on the move. Muddy water can be seen coursing down the slope and pooling at the bottom before running down the road. One resident has watched as the surface level dropped a foot in just two years. The cause is simple: rain washes sediment off the adjacent fields and picks up more as it wears the lane away.

Even more troubling, this rainwater eventually enters a nearby road drain that empties directly into the Cheriton Stream. Excess sediment is a huge problem for chalk streams because it covers their gravelly beds, smothering the fish eggs and aquatic insects that nestle there. It also makes the streams shallower, making them prone to overheating and deoxygenation.

The village's conservation volunteers have attempted to tackle the issue by installing a sediment trap at the lane's lower end. The result has been both vindicating and worrying: below the trap the water runs clear, but it fills every few days in the wetter months. The volunteers take full wheelbarrows to a nearby farm each month, but further help was clearly needed.

We heard about Dark Lane through Watercress and Winterbournes, which allowed us to install another sediment trap further up the lane. Both traps are submerged concrete pits covered by grating: water runs in, suspended sediment settles on the bottom, and the water flows or evaporates out again. The traps now need emptying less frequently and more sediment should be caught overall.

We're so pleased to have been able to work with the Cheriton community on this important project. Thanks also to the landowner for his support. There are lots if interesting projects in our scheme, including many that you can get directly involved in! Explore our work to learn more.