Situated at the foot of the Chiltern escarpment, the historic market town of Watlington is built on top of chalk-fed springs that combine to form the Chalgrove Brook. Confined to brick culverts in the centre of Watlington for at least 140 years, the brook flows out of the town and alongside the road to Cuxham before joining the River Thame at Chiselhampton and in turn to the Thames at Dorchester.  As a spring-fed chalk stream, the upper section of the Chalgrove Brook is a globally rare habitat and is highly vulnerable to detrimental human impact, both accidental and deliberate.  

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Aquatic invertebrate surveys proved that despite hundreds of years of being straightened, buried, built over, narrowed and widened, and used to take surface drainage, the Chalgrove Brook still supported characteristic chalk stream wildlife.  Inspired by the achievements of Sustainable Blewbury’s Millbrook Project, in 2013 Watlington Environment Group began a project to study the physical and social history of the town’s watercourses.  Launched at the church fete, older residents came forward with their memories and old photographs.  The discovery of brown trout a mile downstream at Cuxham further encouraged the group that simple improvements to the existing habitat had the potential to bring significant benefits.

After receiving advice from the Wild Trout Trust and the Environment Agency, plus the all-important EA and landowner permissions, the upper section of the brook has now been successfully realigned through the efforts of volunteer work parties. Work has included clearing blockages, cutting back vegetation to increase light levels, constructing artificial banks from brushwood and stone and flow deflectors to make the brook narrower, deeper, faster-flowing and more meandering, and adding gravel.  

Throughout the project the Group has sought to build links with others, be these existing or emerging like-minded groups downstream in Cuxham, Chalgrove and Stadhampton, and wider afield, or larger not-for-profit organisations and statutory agencies.  This collaborative approach has encouraged and triggered complementary work along the whole catchment, thereby greatly multiplying the value and significance of localised habitat improvements.  A major boost came from the Environment Agency’s prioritisation of related schemes, notably installing a fish pass at Cuxham Mill weir, to ensure brown trout migrating to the upper reaches are able to do so.  Another example of effective partnership was the use in the stream of birch brushwood arising from other habitat enhancement work, cut when the National Trust and the Friends of Watlington Hill were clearing scrub from the chalk grassland there.

In parallel with the practical habitat work, the Watercourses Project has also been raising public awareness of these precious natural resources and the threats they face.  Although the water in the Chalgrove Brook is normally clean enough to support brown trout and various pollution-intolerant species of aquatic insect, when it rains, runoff from the roads enters the network of surface water drains which discharge into the brook and the water quality is reduced.  

Sadly, during a pollution incident in June 2017, all the brown trout in the brook through Watlington were killed by a toxic pollutant that appeared to have entered via one of the surface water drains connecting to the brook.  The exact substance is unknown but the subsequent investigation concluded the most likely cause was the accidental or deliberate disposal of a chemical down a drain.  

With the support of the Parish Council and Environment Agency, Watlington Environment Group produced and delivered fliers to every household to remind people ‘only rain down the drain’.  They continue to champion the brook and its wildlife by attending village events to ask residents to take care over what is poured into the surface drains and to avoid flushing anything into the sewers that could cause blockages.

or more information see https://www.watlington-environment-group.org.uk/watercourses-project/

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