North Portsea Island Coastal Defence Scheme - Phase 3: Tipner Lake - AWARD

Portsmouth City Council - the 'Authority' - is embarking upon a major programme of coastal defence construction. The programme of works is part of the North Portsea Island Coastal Flood Defence Scheme which aims to reduce the risk of coastal flooding and erosion to the area over the next 100 years.

The Authority is now seeking to appoint a contractor via this procurement exercise to deliver Phase 3 of the programme which will cover flood defence works at Tipner Lake from the Mountbatten Centre, Twyford Avenue to the Ports Creek Roundabout.

The Tipner Lake works will consist of the construction of a new reinforced concrete seawall along the full length of this frontage, which is approximately 1.85km in length. The works will comprise a combination of: c. 300mm thick seawall encasement of the existing defences to extend below the existing foreshore level; replacement of the seawall in the southern area of the site where the existing wall is showing signs of structural movement and is considered of too poor a condition to encase; and local re-alignment of the frontage in this southern area where required. There is the opportunity to create a terraced embankment, an environmental zone, seaward of the defences to the north of the site.

The scope of the works at summary level comprise of the following elements, but may not be limited to;

• oDemolition and removal of existing seawall in the southern section of the site;
• oConstruction of vertical reinforced seawall, including sheet pile and bearing pile installation with local realignment;
• oEncasement of the existing seawall in the northern area of the site;
• oThe existing footpath / cycleway behind the seawall will be reconstructed as part of the works;
• oLandscape works to provide appropriate & separate external spaces, including new access points to a public footpath.

The target construction commencement date for the Tipner Lake works is April 2017 with a completion date of October 2018, excluding landscaping works which must be completed by February 2019. It is envisaged that the form of contract used will be NEC 3 ECC Option C. The exact form of contract will be confirmed within the tender documents.

The closing date for receipt of your expression of interest is given against the heading entitled - Date documents can be requested until.