Sewage Discharge Emergency Core Group Meeting

Sewage Discharge into the Winterborne

Date: 19 December 2025
Meeting format: Zoom
Chair: Colin Tracy
Attendees: Jo Lacy Smith, Caroline McMeiken, Deborah Daw, Charlotte Beare, Trilby Fairfax

1. Overview of the Incident

Wessex Water discharged raw sewage directly into the Winterborne stream as an emergency measure to prevent sewage backing up into approximately 31 residential properties close to the river. The discharge was authorised under an existing permit and approved by the Environment Agency. Members expressed shock that this occurred following a prolonged dry summer and concern that the system appeared to move rapidly from apparently stable to crisis conditions after the first period of heavy rainfall. The discharge caused the closure of the road between Martinstown and Winterbourne Steepleton.

2. Impact on the Village and Community

The road closure disrupted daily life, reduced footfall to the village shop, post office, and pub, and affected attendance at church services and community events. Members described a strong sense of disrespect from Wessex Water due to lack of advance notice, warning signage, or public health communication. Concerns were raised that households, residents and dogs and walkers may have unknowingly come into contact with contaminated water.

3. Environmental Concerns

The Winterborne was described as a globally rare chalk stream, highly sensitive to pollution and already under pressure from nutrient run off. Members questioned assumptions that fast-flowing water sufficiently dilutes sewage, noting cumulative downstream impacts and the damaging effects on Poole Harbour, which have been well-documented.

4. Historical Context and Evidence

Monitoring data shows 574 spill events between 2021 and 2024, totaling over 5,900 hours of discharge, with 2024 identified as the worst year on record. Previous tanker use was noted, and their absence during this incident viewed as a significant escalation.

 For further information: https://www.flood-mapper.com/stations/martinstown-ps-winterborne-st-martin

5. Sewage Infrastructure and System Failures

Discussion focused on aging pipes, groundwater ingress, insufficient capacity, and cumulative impacts of upstream housing development outpacing infrastructure upgrades.

6. Regulation, Accountability, and Governance

Although legal, members questioned the Environment Agency’s approval of sewage discharge into a chalk stream. Strong support was expressed for EA representation at any public meeting, alongside Wessex Water, Dorset Council, and the local MP.

7. Key Questions Agreed

1. Why did the system fail so rapidly after a dry summer?
2. Why were tankers not deployed during this incident?
3. Is the system fundamentally inadequate for current demand and rainfall?
4. Would repairs alone be sufficient, or is full replacement required?
5. What pollutants were released and what testing is required?
6. What would full modernisation cost and over what timescale?
7. How can households reduce surface water entering the system?

8. Agreed Course of Action

• Seek technical understanding from Andy Daw and Roland Tarr.
• Coordinate with the Parish Council ahead of a public meeting.
• Prepare an evidence-based briefing for Wessex Water and the Environment Agency.
• Explore safe water quality testing.
• Continue petition promotion and factual communications.
• Maintain a calm, non-confrontational but persistent approach.

9. Long-Term Focus

Water will become a central strategic focus for Green Martinstown over the coming year, including education, investigation, community engagement, and sustained advocacy.