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ABPmer
Quayside Suite
Medina Chambers
Town Quay
Southampton
SO14 2AQ
2015
Beneficial use of dredged sediment
United Kingdom
Deben Estuary (Suffolk)
1.3168131
52.080065
Saltmarsh
0.15 Hectares
Habitat Creation
The Loder’s Cut Island project involved using dredge arisings to restore a small marsh area.
Sediment from Woodbridge quayside and the Deben Yacht Club slipway was excavated using a clam-shell bucket dredge and placed on a local area of marsh by the reverse process.
A 65ft barge (carrying 70 tonnes or 50m³ each load) was used with an aft-mounted excavator. This was suitable for use in the constrained and busy upper estuary. The unloading was done on the top of the high tide with the barge being floated in and out over one high water periods.
In total 1725m³ of silt were placed over three campaigns (in 2015, 2017 and 2018). The recharge site was located alongside a small navigation channel that had been historically created (i.e. 'cut') by hand excavation in this part of the upper Deben estuary. The deposits raised a 1,369m² area of marsh by around a 1m which became a small 'island' at certain high tides. This island was quickly used by roosting birds and the deposits were relatively rapidly colonised by pioneer marsh plants.
The first campaign (in 2015) involved the transportation of 16 barge loads of dredge sediment from Ferry Quay at Woodbridge. A visit in 2016 (a year after this first campaign) indicated that the placed material had remained stable and in situ.
The upper margins of this deposited strip had a thick cover of Salicornia spp. as well as occasional Sea Aster (6-7 plants). There were also signs of invertebrate burrows and bird feeding on the un-vegetated lower margins on the channel/cut side.
During a re-visit in 2019 it was clear that the vegetation cover had increased to support low-mid to high marsh species, Sea Purslane and Linear-Leaved Orache.
ABPmer
Quayside Suite
Medina Chambers
Town Quay
Southampton
SO14 2AQ