Major Investment Transforms Water Quality in River Chess: 85% Reduction in Phosphorus Levels Achieved at Chesham Sewage Treatment Works

£20 Million Investment Transforms Water Quality in River Chess

In a significant environmental breakthrough, Thames Water has announced an impressive £20 million investment in the Chesham Sewage Treatment Works, resulting in an astonishing 85% reduction in phosphorus levels entering the River Chess. This transformative upgrade has seen phosphorus levels plummet from two milligrams per litre to just 0.25 milligrams per litre, marking a pivotal moment for the health of this vital waterway.

Steph Horn, the Chess Smarter Water Catchment Project Coordinator at Chilterns National Landscape, hailed the upgrade as “the single most important step taken to date in improving the water quality of the Chess.” She emphasized the importance of this investment in contributing to the Water Framework Directive (WFD) status of the river, which is crucial for safeguarding the long-term future of this globally significant chalk stream.

Despite the progress, Horn cautioned that much work remains. “While this marks a major milestone, there remains much more work to be done by both Thames Water and partner organizations to secure lasting recovery,” she stated.

Paul Jennings, chair of the River Chess Association, echoed this sentiment, noting that since 2019, improvements have been evident thanks to Thames Water’s investment and Affinity Water’s efforts to reduce abstraction. “This, in conjunction with the work supported by the Thames Water Smarter Water Catchment Project, has created tangible improvements to wildlife numbers,” Jennings said. He reported sightings of water voles expanding their territory, along with kingfishers and little egrets thriving in the urban areas of Chesham and Rickmansworth. Notably, otters have also returned to the river, and populations of wild brown trout have seen a resurgence.

The upgraded sewage treatment works have increased flow-to-treatment capacity from 241 to 353 litres per second, enabling the facility to handle more wastewater during heavy rainfall and significantly reducing the risk of storm overflows. This enhancement is part of Thames Water’s broader initiative to modernize infrastructure and improve river health.

Chris McKenna, Colne and Maidenhead operations manager at Thames Water, emphasized the company’s commitment to delivering reliable services while protecting the health of rivers and waterways amid the challenges posed by climate change and growing demand. “The upgrades at Chesham Sewage Treatment Works are part of our ongoing commitment to delivering reliable services for our customers while also protecting the health of rivers and waterways,” he said.

These improvements are further bolstered by river restoration projects along the Chess and the wider Smarter Water Catchment programme, which has received £3 million from Thames Water over the past five years and recently secured an additional £2 million for ongoing habitat restoration work.

As the River Chess continues its journey toward recovery, the collaborative efforts of Thames Water and local organizations signal a hopeful future for this cherished waterway and the diverse wildlife it supports.