|Durham County Council||Chester-le-Street Flood Alleviation||NEC3 Project Manager and Site Supervisor||December 2020||£2.6m|
Chester-le-Street has a long history of flooding and in June 2012, more than 100 homes and businesses at the northern end of the town were affected. The Cong Burn river was identified as the main cause of the flooding, therefore Durham County Council worked with the Environment Agency to reduce the risk. The solution was to deliver the Chester-le-Street Flood Alleviation Scheme, which involved three phases of work in the heart of the town centre.
The Cong Burn, otherwise known as The Chester Burn, is a river which runs through the centre of Chester-le-Street. Flowing through a concrete channel, the river is mainly hidden from public view and was covered over in 1931 which led to the development of a marketplace, a supermarket and car parking facilities.
The overall flood alleviation scheme will cost £6.2 million and is funded by the Environment Agency (£1.8million through both Grant in Aid and Local Levy), Durham County Council (£1.5million) and the European Regional Development Funding (£2.8million). Chester-le-Street Flood Alleviation Scheme formed part of the overall project, which was valued at £2.6million.
The Chester-le-Street Flood Alleviation design solution involved the relocation of the existing marketplace to a new location within the main works area allowing the existing culvert to be removed and the reinstatement of the riverbed to improve the flood defensives, whilst improving over 100m of watercourse. The design took into consideration the migratory fish passage and ensured there were no obstructions and works were avoided during sensitive times for fish moving to their spawning grounds. The landscaping design was focused on improving habitat and wildlife diversity and utilised native species which create a wetland habitat capable of reducing urban diffused pollution entering the watercourse.
Elvet Chartered Surveyors were appointed by Durham County Council as the NEC3 Project Manager and Site Supervisor administrating the contract in accordance with NEC3 Option A. Elvet worked closely with the other members of the design team which included Pell Frischmann (Structural/Geotechnical), the Environment Agency and Durham County Council. Esh Civils was appointed as the Principal Contractor for the project.
This project has resulted in 72 homes being better protected from flood risk from the Chester Burn and over 400 businesses throughout the town centre will derive some flood risk benefits. Economic analysis identified that this project will achieve approximately £21million of whole life economic benefits over the next 50 years. The project is helping to sustain the existing businesses located in the town centre and attract inward investment in the town to provide further and self-sustaining economic growth.
The channel morphology was also carefully considered as the river is a migratory route for several fish species. This included ripple development to mimic some of the features which are seen upstream including gravel beds and deeper pools.
Other ecological surveys were carried out to protect nesting birds, bats, otters and water voles.
Although Covid-19 had a huge impact on the works, every member of the project team worked together to ensure that the works continued due to the importance of this project. The overriding priority was to ensure the safety of our workforce and the local community. Esh acted quickly to adopt new processes and PPE to ensure the upmost protection against Covid-19.
To ensure that the project was delivered on time and within budget all members of the team embraced the culture of working collaboratively to achieve the objectives. Regular progress meetings were held every month, including fortnightly risk reduction and compensation event meetings to avoid any delays.
The scheme was delivered within budget and on time.