TSC being used to deliver innovative new flood defence gates on Thames estuary

The Environment Agency is using the NEC3 Term Service Contract (TSC) to deliver a pair of innovative dual-function flood and lock gates at the entrance to Tilbury docks on the Thames estuary.

Delivery partners Jacobs and Balfour Beatty started work on the £34 million project in January 2021 under a task order and are expected to finish in 18 months. They are replacing the existing pair of 1928 lock gates with modern new gates, the outer pair of which will also act as flood gates. The life-expired 1981 sliding Tilbury flood barrier will then be removed.

As well as impounding water in the docks, the new gates will reduce flood risk to the Port of Tilbury, the largest multi-modal port in south-east England, plus over 9,000 residential properties in Tilbury, Purfleet and Grays.

NEC3 TSC task order

The work is being delivered under the Environment Agency’s 10-year, £308 million Thames Estuary Asset Management 2100 (Team2100) programme, which was let under an NEC3 TSC in 2014. The integrated delivery team includes the Environment Agency, Jacobs, Balfour Beatty and selected suppliers, and is based on the Project 13 enterprise delivery model.

The team is focused on protecting 1.3 million people and £275 billion of property from tidal flooding until 2100 by managing flood defences more efficiently and effectively.

Environment Agency deputy programme director Helena Henao-Fernandez says, ‘A key part of the NEC3 TSC task order assurance process is confirmation of the savings and efficiencies being delivered on each of the projects.’

She says the programme has a number of tier 2 and tier 3 suppliers on long-term frameworks as part of the integrated delivery team. ‘These suppliers are engaged from the outset of a project, bringing their expertise and knowledge into the early development of solutions. This, combined with the embedment of our operations staff, ensures solutions developed are considering buildability, efficiency and whole-life operability from the outset.’

Reducing site queries

Henao-Fernandez says the approach can be described as, ‘zero change through gateways’, meaning the solutions are developed in evermore detail as they pass through gateways, not redesigning or changing solutions as the project matures towards construction.

‘The people involved in the designs are the people that deliver the construction works. The benefits of the approach are clear in construction, as there are far fewer changes or queries on site than traditional means of project delivery.’

As an example she cites the complex £3.2 million Barking Creek Barrier electrical and control system refurbishment scheme, where only five early warnings were notified throughout the year-long project. ‘And on the £3 million Canal Basin barrier replacement scheme in Gravesend, compensation events totalled only 1.2% of project value.’

The new dual-function gates at Tilbury are being part-funded by the Port of Tilbury, which will also take responsibility for their operation and maintenance. Funding was also secured from the Anglian (Eastern) Regional Flood and Coastal Committee.