A new trial taking place in Chichester hopes to prove that sediment dredged out of marinas can be put to good use, by rebuilding degraded shoreline and reversing saltmarsh decline.
The trial is the first major activity taking place as part of the Solent Seascape Project, a five-year, multi-partnership collaboration funded by the Endangered Landscapes Programme to restore and reconnect the Solent’s coastal habitats.
The Chichester Harbour Protection & Recovery of Nature (CHaPRoN) partnership will look at the benefits of repurposing dredge sediment, which would otherwise be dumped in the English Channel, taking 2500 cubic meters of material dredged from the channel approach to Chichester Marina to rebuild the shoreline where saltmarsh has been lost.
Sarah Chatfield, CHaPRoN Manager, said: “CHaPRoN is very excited about the saltmarsh restoration project at West Itchenor. We’re working in partnership with Land & Water and Earth Change to trial a new and innovative technique that could potentially transform the way clean dredged sediment is beneficially used to restore this important habitat. We have to find new ways of working if we are to reverse this declining trend.”
In addition to physically restoring areas of four key habitat types, Solent Seascape Project partners will work with landowners and regulators to better protect and manage existing habitats, scientifically monitor the benefits of seascape scale restoration and ensure that local people and sea-users co-design the project, thereby becoming more connected and engaged with their local marine environment.
Louise MacCallum, Solent Project Manager of Blue Marine Foundation, said: “It’s so inspiring to see the Solent Seascape Project being kicked off with such an innovative model to restore saltmarsh in one of the Solent’s most beautiful harbours. I am looking forward to revisiting the site in the months and years to come to watch its colonisation by saltmarsh plants.”
In February 2021, Natural England published a report that showed that Chichester Harbour has seen a dramatic loss in saltmarsh habitat: 58.8 per cent of the historic extent of the saltmarsh in 1946 has been lost, with 46.5 per cent of the saltmarsh being lost since designation as a Site of Scientific Interest (SSSI) in 1970. It estimates that on average 2.54 hectares of saltmarsh (the equivalent of more than three football pitches in area) is still being lost every year across Chichester Harbour.
The Solent is recognised as an internationally important wintering and breeding ground for seabirds. The mud and sand flats present in the region support seagrass and saltmarsh and the seabed was once home to the most important native oyster fishery in Europe. All these habitats, like so many others globally, have become fragmented and degraded through anthropogenic pressures including poor water quality, increased industrialisation and disturbance.
This relatively new approach to deposition of sediment for saltmarsh restoration will use a large sleigh to pull the material up the shoreline in stages, as opposed to mechanically spraying material over the area from a vessel as has been used in other projects around the UK.
Healthy salt marsh adjacent to the restoration site at Itchenor which the team hope will re-seed the newly restored area.
The principle will be the same, raising the height of the area should enable pioneer saltmarsh species, such as Cord grass (Spartina spp.) and Glasswort (Salicornia europaea), to recolonise the sediment and stabilise it, allowing other species to follow suit. This is just one of the novel and innovative restoration initiatives that the Solent Seascape Project partners will deliver over the next five years.
James Maclean, Chief Executive Officer of Land & Water, Co-founder of Earth Change said: “We hope this first trial of the new Saltmarsh Restoration Drag-Box technology works well as it will revolutionise the way that saltmarshes will be restored with this circular economy approach”
Marine habitat restoration is its infancy in the UK and as well as restoring habitats the project team will be monitoring the wider benefits of seascape scale restoration, including carbon sequestration, nutrient remediation and connectivity between habitats for mobile species such as fish. As the project progresses the project team hope to use the lessons learned during the restoration work to create a blueprint for restoring temperate marine habitats elsewhere.