What is the Wallasea Island Wild Coast Project?
The Wallasea Island Wild Coast Project is a landmark conservation and engineering project, the largest of its type in Europe. This exciting project is working to transform 670 hectares (ha) of arable farmland into the coastal marshland it once was. This area is more than double the size of the City of London!
The project is a response to the challenges that climate change poses for the UK’s low-lying coastline and aims to future proof this landscape for people and wildlife.
It lies at the heart of an internationally-important estuary, and is a vital part of the Greater Thames landscape. For many, it will be the closest accessible Wild Coast.
Once complete the area will support important bird species and could even re-establish once lost breeding birds, such as Kentish plovers and black-winged stilts.
This project is an example of how amazing things can be achieved through partnership working. Current partners include Crossrail, the Environment Agency, Defra and Natural England.
The project builds on the success of the 115ha of new saltmarsh and intertidal mud created on the north of the island by Defra in 2006. This area, known as Allfleet’s Marsh, is now jointly managed by the RSPB and Natural England.
What will it involve?
The Wild Coast Project received planning permission from Essex County Council in 2009, after an in-depth consultation period.
The first phase of the project was completed by Crossrail. They constructed a temporary jetty in the River Crouch and used this facility to deliver excavated material from its tunnelling operations deep under London. The first material arrived by ship in August 2012.
Crossrail imported just over 3 million tonnes of clean, recovered, soils by ship to shape the new 170ha landform of Jubilee Marsh in the east of the island. Raising the land reduces the volume of seawater entering on each tide. In turn, this also reduces the adverse effects on navigation and shell fisheries that would result from an unmanaged seawall breach.
The Wallasea Island Wild Coast Project is the largest of its kind in Europe and has attracted lots of interest worldwide. The scheme provides an example of how industry and conservation can work together to create something amazing that will not only benefit wildlife, but future generations for years to come.
Why is the Wallasea Island Wild Coast Project needed?
Four hundred years ago there were 30,000ha of wildlife-rich saltmarsh around the Essex coast. Now, saltmarsh is rare, with just 2,500ha left. That’s a loss equivalent to 39,000 football pitches!
In England, saltmarshes and mudflats are being lost at the alarming rate of 100ha each year.
Sadly, this rate of saltmarsh loss will only increase with climate change. Rising sea levels steadily erode the precious mudflats between land and sea and the food-rich environment will be lost to our wildlife forever.
The Wallasea Island Wild Coast Project aims to re-create some of this lost landscape and save it, both for the incredible wildlife that relies on it and for the people that relish it for its restorative benefits and for the pleasure of seeing such places exist.
What will it look like?
Once all the work at Wallasea Island is complete it will be a rich mosaic of habitats. From mudflats to saltmarsh to grassy sea walls and lagoons, wildlife including shelduck, avocet, redshank and the rare oil beetle will find food aplenty.
As sea levels rise the island will act to future proof the landscape for species that are moving in line with climate change and the island will provide a home for nature as their natural homes start to diminish.
Wallasea Island will become an amazing space for people too, with wildlife spectacles galore and a chance to relax in the wilds of Essex.
As stated above, material from the Crossrail project was used to complete Jubilee Marsh (Cell 1). Crossrail completed the delivery of material to site in March 2015, with a total of 3.02 million tonnes of clean earth coming from the construction of tunnels and station below London. A maximum of five ships were used, delivering a peak of 45,000 tonnes per week.
It was recognised early in the consultation process that the management of shipping to avoid potential conflicts with the sailing community was essential. A monthly liaison meeting were held throughout the shipping period. These meetings included Crouch Harbour Authority, the Joint Sailing Clubs Committee, Crossrail, RSPB and Crossrail’s Wallasea Contractors (BAM Nuttall / Van Oord). This frequent liaison helped to manage shipping movements during the most important sailing times, through to a successful conclusion. These arrangements worked well and we are grateful for the help received from those involved.
The material delivered to Wallasea by Crossrail was not sufficient to complete the ground forming required in Jubilee Marsh. The balance was gained on site through the creation of new wildlife habitat elsewhere on the island. These diggings provided close to a further million tonnes of material, through the creation of the Cell 3 lagoon (40ha), the Cell 5 lagoon (25ha), a ditch/lagoon network (18ha), an anti-predator ditch (3.2km) around the grazing marsh and the phase two water vole mitigation habitat (3.5ha).
The ground forming of Jubilee Marsh was completed in May 2015. Following extensive pre-breach groundworks to seaward, starting in April, the seawalls were finally breached at three locations on 11 July 2015. This was a huge milestone for the RSPB Wallasea Island Wild Coast Project, with the wall beaches allowing water to enter the east/south of the island (in a managed way) for the first time in 450+ years.
The material used to create Jubilee Marsh was placed using a 3-D ground model, with a variance of just 0.1% i.e. just 2,000m3 out of the 2,000,000m3 placed. The area has an average covering of 1.5m across the whole 170ha but the material is placed with very subtle ground height variation to produce a very natural looking topography. The varied placement, with a maximum depth of 3.5m produces tidal creeks, mudflats, the full range of saltmarsh habitats, with lagoons, grading into to terrestrial grassland on 1:40 side slopes. The 2.4km footpath along the top of the new seawall was opened in autumn 2015, leading to one of two new wind shelters.
We further enhanced the area with the placement of 300m3 of a mix of course sand, shingle and cockleshell on two liner islands over an area of 2,000m2. We also have a specifically engineered spoonbill nesting area - a lagoon with a kidney shaped island high enough to support willow/tamarisk, planted in autumn 2015.
The site is developing really well and as predicted. During its first winter Jubilee Marsh had a peak usage of just over 10,000 birds. These were made up of a mixture of wildfowl and waders, with key wildfowl species being: brent goose, shelduck, teal, wigeon and pintail; and waders: grey plover, ringed plover, dunlin, curlew and redshank. Breeding birds in 2016 included black-headed gull (197 pairs), common tern (8), little ringed plover (5), avocet (101) and redshank (17).
We have now transformed 65% of the island, in terms of land forming. In autumn 2015 we allowed saline water into the 40ha Cell 3 lagoon, to the south and west of the material handling system. Also, with the installation of a further 12 water control structures in summer 2016, we now have full control of the water levels throughout the Cell 5 habitats, as detailed above. Two new circular footpaths will be opened shortly, allowing the exploration of these new and rapidly developing habitats.
To complete the project to the currently consented design would require a further eight million tonnes of clean soils. We have been working very hard to find extra material but it is proving difficult. We have not changed plans yet but we have been considering a ‘Plan B’. This would involve using an existing seawall sluice in the south of the island to allow saline water into a series of shallow lagoons using low bunds and the existing topography. The water would flow off via Cell 3 and out through the northern outlet sluice into Jubilee Marsh. If we go down the Plan B route then a new planning submission would be required and would also lead to the removal of the Material Handing System. This alternative would be designed to last 50 years and not rule out future material import.
We would like to thank the Crouch Harbour Authority for their continued support and positive engagement with the Wallasea Island Wild Coast Project.
RSPB Wallasea Island Project Manager
26 October 2016