Knights Brown was appointed to carry out Phase 2 of the 10 year North Portsea Island Coastal Flood & Erosion Risk Management (CFERM) project to improve the coastal defences at Milton Common and demolish Great Salterns Quay.

The works comprised construction of a 750m long erosion control rock revetment, three flood bunds varying in height from 0.2m to 1.5m, the demolition and removal of the disused Great Salterns Quay, construction of a sheet piled sea wall, and footpath, reinstatement and landscaping to improve biodiversity in this heavily environmentally designated area.

The works were carried out very close to residential properties and large portions were constrained by tides. Significant environmental mitigation was required throughout the construction phase.

When protected sea snails were identified in the proposed location of the haul route, we rerouted it over the flood plain and by temporarily dressing it and leaving it in place for reuse in Phase 4, achieved a cost saving of £240k.

Reusing chalk recovered from the demolition of the quay to form the new flood bunds, realised a savings of £1m. And further savings of £360k were achieved through the reclassification of non-hazardous material as inert and using surplus material as backfill.

North Portsea Island CFERM Phase 2 won Civils Project of the Year at the 2017 Constructing Excellence in London and the South East Awards.

Knights Brown has since been awarded Phase 3 at Tipner for the construction of a 1.85km sea wall including wall encasement, slipway and revetment construction, with a value in excess of £10m.