Knights Brown will start work immediately on the last stage works which will take place along Ports Creek in North Portsea and will include 1.9 km of flood defences.
The design consists of a sloped earth embankment, which provides the required flood defence level, with a rock armour toe to dissipate wave energy.
Knights Brown previously constructed the second and third phases of the big south coast flood defence project, which is one of the largest local authority-led coastal flood defence projects in the UK.
The defences will safeguard more than 4,000 homes and almost 500 businesses. In total, it covers 8.4km of coastline from Tipner through to Milton.
Divisional Director, Mike Crook, said: “Our extensive expertise in coastal civil engineering and our local knowledge will enable us to deliver this essential flood defence scheme, which will safeguard residents and businesses for the next 100 years. ”
Work is being carried out in collaboration with an on-site archaeologist and Historic England as the work area is next to the Hilsea Lines which are a line of 18th and 19th century fortifications built to protect the northern approach to Portsea Island.
They formed an important part of Portsmouth’s defences and are the best surviving example of a bastioned and casemated defensive line built in England and are a Scheduled Ancient Monument.