Thames goes live with EDM map across its region

Thames Water has gone live with a near real-time data regional map of all its event duration monitors (EDMs) showing where sewer overflows have spilled.

The interactive tool is the first of a company’s entire region, covering the 468 permitted discharge points across London and the Thames Valley.

With a traffic light-style system, anyone can view where there are combined sewer overflows (CSOs) on rivers and waterways to make informed decisions about using swimming or watersports.

It shows when an EDM has been triggered in the past 48 hours, how long it spilled for, and if it is still in use.

Following a successful trial in the Oxford area, the company expanded the tool to cover all locations. It is part of Thames’ River Health Action Plan to make radical improvements to performance and transparency with the aim of protecting and improving the environment.

“We are absolutely committed to protecting and enhancing our rivers and the communities who love them, and we want to make these discharges of diluted sewage unnecessary as quickly as possible,” a spokesperson for Thames told Utility Week. “We want to lead the way with this transparent approach to data and the alerts will be available through an open data platform for third parties, such as swimming and environmental groups, to use.”

Thames is the first in the sector to offer the alerts for all locations and inland waters. Southern and South West have each made data available on coastal CSOs. By the end of 2023 water and wastewater companies in England are required by the Environment Agency to have EDMs installed at all CSOs to give a complete picture of the number of times these are triggered.

The company stressed its ambition is to stop the need for discharges, which was a core driver of shareholders’ approving an additional £2 billion of funds last year. Thames said this extra money would allow it to deliver its commitment to a 50% reduction in the total annual duration of spills by 2030, and within that an 80% reduction in sensitive catchments.

Upgrades are underway to Mogden sewage treatment plant and capacity is being increased at sites across Thames’ region including Witney, Chesham and Fairford, which are due to be completed by 2025.

“We have a long way to go – and we certainly can’t do it on our own – but the ambition is clear,” the spokesperson said.