Thames Water’s £20 Million Upgrade: A Major Leap in Water Quality for the River Chess
Thames Water’s £20 Million Upgrade Transforms Chesham Sewage Treatment Works, Boosting River Chess Health
Chesham, UK – In a significant environmental milestone, Thames Water has announced the successful completion of a £20 million upgrade to the Chesham Sewage Treatment Works, resulting in an impressive 85% reduction in phosphorus levels in the River Chess. This upgrade has already demonstrated a measurable impact on water quality, heralding a new era for the river’s ecosystem.
The phosphorus reduction scheme has lowered phosphorus concentrations from 2 milligrams per litre to just 0.25 milligrams per litre. Lower phosphorus levels are crucial for fostering healthier and more balanced river ecosystems, which are vital for the flora and fauna that depend on these habitats.
Steph Horn, Chess Smarter Water Catchment Project Coordinator at Chilterns National Landscape, hailed the upgrade as the “single most important step taken to date in improving water quality of the Chess.” Professor Mike Bowes, Nutrient Hydrochemist for the Centre for Hydrology and Ecology, echoed this sentiment, stating, “The phosphorus reduction scheme at Chesham Sewage Treatment Works has already made a measurable impact on water quality.”
In addition to reducing phosphorus levels, the upgrade has increased the site’s flow-to-treatment capacity from 241 litres per second to 353 litres per second. This enhancement allows the facility to treat more wastewater, significantly reducing the risk of storm overflows during heavy rainfall or prolonged groundwater infiltration.
Thames Water is also advancing a series of river restoration projects along the River Chess, aimed at creating a more resilient and sustainable chalk stream environment. These initiatives will enhance vegetation, improve habitats, and boost overall biodiversity. This work complements the River Chess Smarter Water Catchment programme, which has seen £3 million invested by Thames Water over the past five years. The initiative unites local partners and stakeholders to achieve greater improvements in river health than any single organization could accomplish alone.
An additional £2 million has now been committed to the catchment, enabling ongoing collaboration with local communities to implement the flagship Chalk Stream Restoration Plan and enhance river habitats for the long term.
Professor Bowes emphasized the importance of continued monitoring, stating, “We will continue to monitor its progress as part of our Floods and Droughts Research Infrastructure programme and hope to work closely with Thames Water as part of ongoing efforts to improve water quality and river health.”
Chris McKenna, Colne and Maidenhead Operations Manager at Thames Water, reiterated the company’s commitment to environmental stewardship. “Our purpose is to deliver life’s essential service, so our customers, communities, and the environment can thrive. The upgrades at Chesham Sewage Treatment Works are part of our ongoing commitment to delivering reliable services while protecting the health of rivers and waterways.”
Steph Horn added, “The funding provided to the Chess Smarter Water Catchment Initiative has enabled partnership working at a catchment scale, driving improvements to the Chess at a level not seen for over a century.” She noted that the initiative has supported farmers in land management changes, delivered river restoration schemes, and fostered community connections through educational and citizen science programs.
Paul Jennings, Chair of the River Chess Association, highlighted the positive changes observed since 2019, attributing them to Thames Water’s investment and collaborative efforts. “We have seen tangible improvements to wildlife numbers, with Water Voles expanding their territory and Kingfishers and Little Egrets being spotted in urban areas. Otters are now seen along the river, and wild Brown Trout populations have increased.”
While celebrating these achievements, Jennings acknowledged that challenges remain. “Further work is required as we face emerging issues, particularly groundwater ingress into the sewer network and the need for further reductions in abstraction.”
As the River Chess embarks on this promising journey toward recovery, the collaborative efforts of Thames Water, local communities, and environmental organizations are paving the way for a healthier, more vibrant ecosystem for generations to come.