LONDON'S SUPER SEWER CUT MODELED STORM-OVERFLOW VOLUME 86%.
London's new tunnel intercepted most of the storm-overflow volume its designers modeled for 2025.
Tideway's first full-year report estimates that London's new super sewer reduced storm-overflow volume by 86%, prevented 84 tonnes of sewage-derived litter from reaching the tidal Thames, and sharply reduced modeled high-health-risk days.
WHAT HAPPENED
The report compares a pre-Tideway annual average of more than 21 million cubic metres with just under 3 million cubic metres in 2025. It estimates that days with elevated water-quality health risks fell from 75.7% before Tideway to 10.4%, while noting that 2025 rainfall was lower than average.
WHY THIS IS HOPESLOP
The useful story is infrastructure doing exactly the unglamorous work it was built to do: intercepting pollution at city scale. The dry-year caveat matters, but so does the magnitude of the modeled change.
ORIGINAL SOURCETidewayRead the original report
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