The state of the River Meon
The Chalk aquifer of the South Downs National Park stores drinking water for 1.2 million people in the southeast and feeds local streams and rivers in the region. This aquifer is also the source of a number of the world’s 200 precious chalk streams, 80% of which are in Southern England including the River Meon.
The Meon was identified by the National Rivers Authority in 1991 as suffering from acute low flows caused by abstraction. In 2025 its flows still do not support good ecological status with the water industry identified as the main reason for failure. 100% of the river is in moderate ecological status.
Neither a Special Area of Conservation nor a Site of Special Scientific Interest – and with the protected status of the National Park currently counting for little in water company planning – this “over-abstracted” river has no protection. If licences were fully implemented up to 70% of the Meon’s flow could be abstracted, causing significant environmental damage.
It’s not just abstraction impacting the river, the warming effects of climate change are having a serious impact on its wildlife. As the river heats and flows drop, pollutants became more concentrated. Downstream, the estuary has heated up to an astonishing 25 degrees Celsius, disastrous for migratory fish that use the rivers to spawn, resulting in critically low salmon numbers (mirrored on rivers across the South, including the neighbouring Itchen and the Exe in Exmoor).
Shady banks and cooler temperatures are a blessing for fish in a changing climate, however, the habitat score for the river is only 36 out of 100. This means that the habitats along the river are lacking in diversity and the natural features which help manage the impacts of erosion, pollution and climate change restricting the ability of the river’s wildlife to thrive. River restoration led by the Hampshire and Isle of Wight Wildlife Trust and Wessex Rivers Trust is starting to address that. A water vole reintroduction by the South Downs National Park has been successful, returning this rare species to the catchment.
The biggest challenge for the river remains the water industry which is highlighted as the reason for not achieving a good status. There were 3,240 hours of storm overflow in the river in 2024 and sewage treatment works, septic tanks and storm overflows combined accounted for 80% of the average dissolved phosphorus present in the river. More broadly, the water industry is indicated as a reason for failure in 80% of failing water bodies in the South Downs National Park, whilst agriculture and rural land management is also significant impacting 70% of failing water bodies.
