Stopping Sediment at Stoke

Fencing on the Bourne Rivulet at Stoke © Wessex Rivers Trust

The clear water and gravelly beds of chalk streams offer fantastic habitat for wildlife. At Stoke, the Watercress and Winterbournes partners have been working to keep them that way.

For the village of Stoke, the Bourne Rivulet is a prominent feature of the local landscape. At this point in its journey the stream is a natural winterbourne, meaning that it doesn't flow all year round. Instead its waters come and go, fed by rainfall stored in an underground aquifer.

Until recently, if you'd visited the area during a dry period you may have spotted something worrying. Several stream-adjacent fields hold cattle, which had been walking and grazing along the banks. This loosened the soil, eroding the banks and causing sediment to settle on the stream bed.

In February 2021, Wessex Rivers Trust teamed up with a local landowner to tackle this issue at its source. Improvements were made at two local sites, as part of the Watercress and Winterbournes Landscape Partnership Scheme.

Excess sediment poses a real problem for wildlife, particularly fish like the brown trout. It smothers the gravel in which they lay their eggs, seriously hampering the development of their young. This also makes the stream less suitable for gravel-loving insects like damselfly larvae.

At Stoke, there was a significant build-up of sediment in certain parts of the stream. Marginal plants, which help to prevent bank erosion by securing the soil, were limited by cattle grazing. This lack of vegetation exacerbated the sediment issue, as well as reducing the habitat for species like water voles.

Luckily the solution was a simple one: add fencing to keep the cattle off the stream bank; drinking troughs will ensure the animals still have access to clean water. The cattle at one site were rarely moved, so 150m of new fencing did the trick, but at the other site a different solution was needed.

Cattle can actually be helpful for nature, as long as they're managed in the right way. Unlike mechanical mowers they choose which plants to eat, thereby increasing plant diversity. They also flatten parts of the vegetation, which creates a more varied habitat for wildlife.

At the second site, the cattle had often crossed the stream to graze a small field on the other side. A such, we installed 400m of fencing to protect the banks, but also included a Hampshire gate. This will allow the landowner to move his cattle, so that the small field can still benefit from occasional grazing.

We're very happy to have given the Bourne Rivulet greater protection - huge thanks to the landowner for his support and to Wessex Rivers Trust for leading on the works. Don't forget that Watercress and Winterbournes has many more exciting projects, with lots of ways for you to get involved!