The Great Fen — A 100-Year Plan to Rewet 3,700 Hectares of Drained Peat Fenland (England)

The Great Fen aims to create a roughly 3,700 ha mosaic of wet habitats in Cambridgeshire, linking two remnants of ancient fen, Woodwalton Fen and Holme Fen, in a 100-year vision (now about twenty years in). The region has lost around 99% of its East Anglian fen, and drained peat under farmland is reported to be vanishing at about 2 cm a year; the approach is a controlled raising of water levels and gradual rewetting of peat soils. The lead organisation is the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire, with the Environment Agency, Natural England, Huntingdonshire District Council and the Middle Level Commissioners (who run the local drainage), and UKCEH on carbon research.
A 2008 Heritage Lottery Fund grant was described as the largest ever awarded to the natural environment, and the 2010 Living Landscape masterplan guides delivery. About 1,700 ha is now managed for nature conservation, of which 1,200 ha is restored land. Reported outcomes include otters breeding on site, common water voles, booming bitterns no longer rare, lapwing chicks hatching annually, new colonisation by grasshopper warblers and corn buntings, and the tansy beetle rediscovered at Woodwalton Fen in 2014 after being last recorded in 1973.
Caveats: UKCEH flux chambers underpin confidence that net-zero carbon loss is achievable on many new habitats, but this is a stated aim, not a published measured result; no total programme cost or peat-loss/carbon tonnage is given in the sources consulted. Rewetting beside intensively farmed land also depends on wider water management. The case is a strong governance and biodiversity example with carbon evidence still pending.

Read the full analysis: https://www.ciwem.org/the-environment/raising-the-waters-%E2%80%93-a-100-year-plan-for-great-fen