Sustainable Warminster Column: Warminster’s chalk streams – the cleanest water on Earth?

The idyllic English summer: imagine lively, cool, clear water, sparkling over pristine gravel beds – dabble your feet on a hot summer’s day and watch the wildlife flitting around the stream’s surface.

Here in Warminster, we’re privileged to live near the porous chalk geology that makes up Salisbury Plain and the Wiltshire downs. Rain falls and seeps through the chalk for hundreds of feet. It takes decades to filter down slowly between the rock.

Eventually, it springs out of the ground and forms streams, which are some of the cleanest natural waters on Earth. These are precious and globally rare resources with their own special ecology. Our most accessible local chalk stream is the River Wylye.

Recently, Sustainable Warminster members took part in ‘Waterwatch’.

This national citizen science project involves testing rivers and streams to measure the nitrates and phosphates present in water. These are both pollutants (and there are others not so easy to measure) coming from imperfectly processed sewerage discharges, septic tanks or agricultural run-off from fields bordering the streams; raised levels indicate a decline in water quality.

We found all sites tested exceed the acceptable limit by a wide margin.

This suggests agricultural run-off (fertilizers and/or manure) or sewage contamination is affecting our rivers. This can lead to oxygen depletion – freshwater invertebrates and fish may be at risk of harm.

Pollutants also make water unsuitable for human recreation and local wildlife. Waterwatch is happening again in September. You can register to receive a testing kit here: https://earthwatch.org.uk/greatukwaterblitz/#register

Chris Walford, Sustainable Warminster