New and updated carbon saving flood defences for Lincoln City
Working alongside our strategic partner JBA Bentley, we have supported the design and installation of new and improved carbon saving flood defences at eight different locations across Lincoln – lowering the risk of flooding for 1,842 households and improving the economic value of the land.
- Client Environment Agency
- Location River Witham, Lincoln
- Services Engineering
Improving existing flood defences
Lincoln City is subject to fluvial and surface water flooding. The day-to-day flood management of the catchment is dependent on a system of linear flood walls and sluice gates. However, all of these defences were nearing the end of their design life. Prior to the beginning of the works, two incidents occurred where the old sluices did not open in a timely manner which would have resulted in significant flooding. There was also reports from residents of leaking and flooding through flood walls.
Reducing flood risk and increasing catchment resilience
The new and improved flood defence system in Lincoln reduces flood risk and improves the catchment resilience up to a 1% Annual Exceedance Probability (AEP) event. The scheme is split across five working areas which include:
- Repair works along the Witham walls
- Replace Great Gowt
- Stamp End Sluice
- Bargate Sluice
- Re-building Foss Bank
The creation of a hub in the city centre enabled easy access to sites in the surrounding area. Each site came with a challenge of working in tight public areas, however employing techniques such as silent piling meant minimal disturbance to neighbouring areas.
Carbon saving flood defences
The project lowers flood risk for 1,842 households and provides £32.95million worth of benefits to the whole life cost of existing infrastructure. Currently three of the five sites have been constructed with the remaining two (Stamp End and Foss Bank) delayed due to a flooding event. As a result of this, around five additional assets requiring refurbishment are now incorporated into the main contract. The combined works provide flood protection to an estimated 4,000 properties.
The Sluice gate structures and Witham Walls also exceeded the Environment Agency’s carbon reduction target of 40%, with Sluice gate structures whole life carbon saving at 93% and Witham Walls whole life carbon saving at 47%.