Construction of Earthworks Portland Grounds

The contract was completed on time despite numerous delays and a complete redesign of the Eastern half of the works. McCarthys were able to respond quickly with additional in-house resources to minimize the impact and maintain programme.

The contract was exemplary for Environmental, Health and Safety standards evidenced by it becoming the only contract NRW have ever given a SHE Audit score of 100% on the WEM Framework.

Cost and programme savings were achieved by innovatively using the permanent embankment material as a 'capping layer' under the temporary haul road. This meant the total volume of import through the narrow lanes was reduced, no material needed to leave site and there was a significant programme saving.

The Works

The work involved the raising of the flood defence embankment for approximately 2200m by around 0.6m to 0.9m. The new embankment level of 9.41mAOD gives increased protection against flooding from the estuary.

A 4m wide access track was constructed on the land-side of the embankment to enable vehicular access for construction, maintenance and emergencies. Due to the location of the existing reen Welsh Water main and hedgerows, a 600mm high Redi-Rock retaining wall was required to retain the earth embankment at the pinch-points along the embankment.

Great efforts were made to minimize the impact to Severn Estuary Natura 2000 site (collective name describing SSSI/ SPA/SAC/ Ramsar site), with particular regard to the sensitive saltmarsh environment on the seaward side of the bund construction.