Chalk stream tributary of the River Thames joins Salmon & Trout Conservation’s volunteer led river monitoring

The South East Rivers Trust has joined Salmon & Trout Conservation’s (S&TC) SmartRivers programme to monitor water quality on the River Hogsmill in Surrey. SmartRivers uses invertebrate samples to monitor water quality alongside the rivers capability to support healthy populations of wild fish.

Much loved by the local community, the River Hogsmill is one of only 200 chalk streams in the world and a tributary of the River Thames. Sadly, like many urban rivers, it suffers a range of pressures and consequently significant habitat degradation.

Jess Mead, from the South East Rivers Trust, said: “we hope that by joining Salmon & Trout Conservation’s SmartRivers project, we will further equip our existing network of citizen scientists and allow them to develop knowledge of the river and what is needed to restore it.

“Water quality is of real concern for the Hogsmill. Two consented storm tanks in the headwaters of the stream discharge sewage during high rainfall, and major road networks in south London cross the river causing road runoff and toxic pollutants to wash into the river through surface water. The Hogsmill also faces threat from inadequate infrastructure with residential properties discharging water directly into the river from washing machines and bathrooms. All these pollutants have been exaggerated more recently with the river experiencing extremely low flows, resulting in less water to dilute the increasing pollution”.

Rubbish floating on the River Thames after a storm.
Rubbish floating on the River Thames after a storm.

Lauren Mattingley, SmartRivers project manager, added: “A volunteer-led scheme, SmartRivers is designed to upskill volunteers, and supports the collection of high-quality data that can be used to target river restoration projects.

“SmartRivers monitoring has a wide range of applications. One of these is to see if remediation actions have led to river improvement from a biodiversity perspective. A huge variety of river improvement projects take place without high resolution before and after monitoring in place. SmartRivers fills this gap, providing long-term evidence of how work has impacted water quality. We are delighted that the former Surrey Branch of the Salmon and Trout Conservation have sponsored the cost of this project and really look forward to seeing how the invertebrate communities respond to the efforts being made on the River Hogsmill”.

To find out more about SmartRivers, please visit the SmartRivers page or email