Thames Catchment Management Steering Group (TCMSG)
The TCMSG was formed in 2010 by Affinity Water, Thames Water and South East Water to jointly investigate the impacts of metaldehyde and other pesticides in the Thames River Basin District.
All three companies have agreed a programme of work with the Drinking Water Inspectorate (DWI) to work with landowners, farmers and agronomists to identify solutions to reduce metaldehyde. Since its formation, the TCMSG has developed a combined river sampling programme which covers most of the 16,000km² of the Thames River Basin District. The river sampling helps to identify hot-spot areas where pesticide concentrations are highest, and develop consistent messages and investigate catchment-based solutions to prevent metaldehyde and other pesticides getting into surface waters at the source, rather than relying on complex and expensive treatment at our water treatment works.
Every year the TCMSG hosts a workshop for key stakeholders including the Drinking Water Inspectorate (DWI), the Environment Agency (EA), Natural England, the Health and Safety Executive, agronomists, Campaign for the Farmed Environment and pesticide manufacturers and distributors. These annual stakeholder events are an opportunity for the TCMSG to update on the pesticide sampling programme, present progress on projects like our Zero Metaldehyde pilot in the Mimmshall Brook, and discuss issues impacting on untreated water quality in an open forum.

Affinity Water Catchment Management Manager engaging with the TCMSG at the annual workshop.