Heathrow expansion would involve merging, culverting or redirecting five rivers, directly affecting at least two kilometres of waterways. The River Colne, Wraysbury River, Colne Brook, Longford River and Duke of Northumberland's River are all at risk. Some stretches would be forced through dark pipes, severing ecological connections between the Chilterns and the Thames and threatening wildlife including eels, trout and otters.

The Government’s own assessment identifies seven internationally important habitat sites that may be affected. Impacts could include habitat loss, disturbance, air pollution and changes to river systems.

This includes:

- Burnham Beeches Special Area of Conservation (SAC)

- Chiltern Beechwoods SAC

- Richmond Park SAC

- South West London Waterbodies Ramsar and Special Protection Area (SPA)

- Thames Basin Heaths SPA

- Thursley, Ash, Pirbright & Chobham SAC

- Wimbledon Common SAC

- Windsor Forest & Great Park SAC

Expansion would wipe out a third of the southern part of the Colne Valley Regional Park, which is a precious green space for wildlife and local communities. Additional water demand could also put further pressure on the wider catchment, including globally significant chalk streams.

Climate: The UK urgently needs to cut emissions, not make it harder to meet climate commitments. The Climate Change Committee has warned that Heathrow expansion would make meeting the UK's climate targets impossible without significant changes to Government policy.

Protection for wildlife: Eels, trout, otters and other species dependent on healthy rivers and connected habitats.