The River Cam, a picturesque centrepiece of Cambridge, is currently facing a series of pressing issues that are raising concerns about its long-term health and accessibility. Among the most immediate threats are the ongoing closure of Jesus Green Lock, a recently collapsed section of the river embankment, and persistent worries over water quality due to sewage discharge.
Jesus Green Lock, a key part of the city centre waterway, has been out of action since May 2024 following the discovery of structural defects. A recent report, commissioned by Cambridge City Council, has shed light on the extent of the damage, revealing significant underwater erosion of the lock's structure. The report suggests that inadequate past repairs may have contributed to the current state, noting that previous wall repairs did not match original construction materials or standards of workmanship. The lock, a Grade II listed structure dating back to around 1832, may also have had repairs carried out without the necessary listed building consent.
Adding to the river's woes, parts of the embankment adjacent to Jesus Green Lock were cordoned off recently due to severe deterioration and a partial collapse. Liberal Democrat Councillor Cheney Payne described the incident as the bank having “given way” next to the lock. Cambridge City Council, responsible for this section of the embankment, has stated it is working to appoint a contractor for repairs, while monitoring the situation and maintaining safety measures. The Council and The Conservators of the River Cam, the body responsible for maintaining the lock, are hoping to coordinate repairs to achieve cost efficiencies.
Beyond the structural integrity of the lock and embankment, environmental concerns regarding the River Cam's water quality are also growing. Green Party Councillor Eleanor Toye-Scott recently raised a motion highlighting water depletion and expressing alarm over sewage discharge into the river. The motion cited claims of 1,700 sewage incidents occurring in 2025. Councillor Payne has also voiced fears that the prolonged closure of Jesus Green Lock could lead to reduced water levels, potentially turning sections of the Cam into a “muddy trickle”.
The Conservators of the River Cam, an organisation established in the 1700s, maintains the lock and relies on user fees for its income, receiving no taxpayer funding. However, city councillors have previously advocated for a change in this funding model. The combined challenges of structural decay, environmental pollution, and potential water level reduction pose a complex threat to one of Cambridge's most iconic and historically significant natural assets.