Flood-defences maintenance works

Tender description

The Hawick Flood Protection Scheme (Scheme) is a major project advanced under the Council’s Flood Protection Scheme Programme. The Scheme has been developed by the Council and their Design Consultant, Jacobs (formerly CH2M Hill and Halcrow) since 2010. The Scheme will deliver flood protection against the 1 in 75 year flood event to 930 residential and commercial properties at risk along the river Teviot and Slitrig water through Hawick. The Scheme will also deliver multiple benefits to the town of Hawick, maximising the cultural, heritage, educational, environmental, energy and health opportunities that a major civil engineering project can deliver in partnership with the community and external organisations. The Scheme has been approved under the Flood Risk Management (Scotland) Act 2009 and the Design Consultant is progressing the Detailed Design. The Main Works Contract is the single construction contract through which the construction works of the Scheme will be delivered. This project is for the delivery of a flood protection scheme to the town of Hawick. The total length of flood defence wall will be approx. 5,93 km, with 5,6 km of walls (including glazing and stone cladding in parts) and 0,33 km of embankments. SEPA approval has been obtained that approx. 1,6 km of these walls will be constructed from the wet side (in river). — Where the height of the new flood defences is greater than 1,4 m above existing ground level it is intended, where possible, to raise the existing ground level behind the new defences to restrict the height to no greater than 1,4 m — There will be a minimum of ten new flood gates / demountable barriers, — The walls have been designed for a lifespan of 100 years minimum, — The foundations of the flood defences have been designed such that the defence heights can be increased to protect against the 1 in 100 year flood event, — The average height of the defences will be approximately 1,6 m above existing ground level, with a maximum of 2,55 m at the High School, — The defences will also provide sheet piled seepage protection, improved surface water drainage and up to eight surface water pumping stations, — The defences will be predominately of sheet pile construction with reinforced formed concrete walls above ground, — Approx. 15 % of the length of the walls will include glazing panels — Approx. 9130 m2 of concrete flood wall will be clad with natural and reconstituted stone. The Scheme will provide approx. 185m of new culverts, and up to 2,5 km of erosion protection for the riverbank and to of some flood walls. Included in the Scheme is the removal and replacement of 3no. footbridges, and a linked minimum 2,5 m wide sustainable combined footway/cycleway over the length of the Scheme.