Saltmarsh recreation by managed realignment, Hesketh Out Marsh – UK

Hesketh Out Marsh, on the southern shore of the Ribble estuary near Preston (UK), was cut off from the estuary by an outer wall in 1980 and farmed as cropland. Facing rising sea levels (a projected ~84 cm by 2100) and an expected 20% increase in peak watercourse flow by 2100, the Royal Society for the Protection of Birds (RSPB) and the Environment Agency pursued 'managed realignment' — deliberately reintroducing tidal water to recreate saltmarsh, both as bird habitat and as a natural buffer that absorbs wave energy ahead of the area's flood defences.

The project aimed to protect adjacent built assets and infrastructure from flooding and help the estuary adapt to sea-level rise, while creating low-maintenance intertidal habitat for nature conservation, avoiding harm to water quality on nearby bathing beaches, and preserving landscape and heritage character.

The RSPB bought half of Hesketh Out Marsh in 2006. After upgrading the inland embankment, the Environment Agency breached the 1980s outer embankment in 2008, letting tides recreate 168 hectares of saltmarsh. A grant from FCC Environment later let the RSPB purchase the remaining land ('Hesketh Out Marsh East'); works to strengthen the inner flood bank and reshape the land ran from 2014 and the outer bank was breached in 2017, restoring saltmarsh across a combined 322 hectares.

The Environment Agency estimates the first phase saved about £2 million by reusing excavated on-site soil for bank works rather than importing material. The second phase's total out-turn cost was £7.2 million, covering Environment Agency project management and RSPB land purchase/management costs. The completed site now protects around 140 residential properties and 3 commercial buildings from a 1-in-200-year flood event, and its 322 hectares of restored saltmarsh dissipate tidal energy, improve coastal-defence resilience, and provide Habitats-Directive-priority intertidal habitat. Monitoring of bird species richness and abundance has confirmed positive habitat development for target species including redshank, avocet and lapwing. The site also draws about 10,000 visitors a year as a recreational and educational resource for the Ribble Coast & Wetlands Regional Park.

Success factors identified include sustained partnership between the Environment Agency, RSPB, Natural England and Lancaster City Council; funding and political support secured through several project phases; and an ecosystem-based, adaptive management approach. Constraints included local landowner concerns about upstream land drainage, which shaped the scheme's design, and the risk of bird-strike at a neighbouring aerodrome, which limited lagoon size to 1 hectare, excluded nesting islands from the design, and required an ongoing monitoring system.