Year
2021Duration
3+ yearsCost
£4.6mLocation
United KingdomProject achievements
Solved the problem
Provided flood protection for around 4,000 homes and businesses
Area improved
£32.95 million-worth of benefits to whole life cost of existing infrastructure
Environment benefitted
Whole life carbon reduced by 93% for sluice gate refurbishment
Improving Lincoln’s catchment resilience up to one in a 100-year flood event risk
Lincoln lies on the River Witham, which can be subject to flooding. The city’s flood management was dependent on a system of linear flood walls and sluice gates (barriers that slide in grooves set in the sides of waterways) which were nearing the end of their design life.
The Lincoln Flood Defences project included repairs and upgrades across five working areas:
- Repairs along Witham flood walls
- Replacing sluice gates at Great Gowt, Stamp End and Bargate
- Re-building Foss Bank flood defence
The original scheme was then expanded to carry out sheet piling (used for retention) at Dixon Street, Spa Road and Sincil Dyke as well as further wall repairs at Sincil Bank and Boultham Avenue.
Furthermore, eel passes were integrated at the Bargate and Stamp End sluices, and a canoe portage was installed at Altham Terrace on River Witham for the local canoe club.
The works have improved catchment resilience up to the one in 100-year flood event risk.
It protects an estimated 4,000 households from flooding while providing £32.95m of benefits to the whole-life cost of existing infrastructure.
Working in a city meant working among a large community, so a community liaison officer was on-hand to deal with any questions.
The team also worked closely with stakeholders including the Canal and River Trust, Lincolnshire County Council, Lincoln City FC and houseboat residents permanently moored on the canal.
Did you know …
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Around 4,000 homes and businesses are protected by works to improve flood defences at multiple sites across the city centre.
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Over 1,100 linear metres of sheet piling were installed across the city.
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Whole life carbon was reduced by 93% by challenging original refurbishment plans, instead replacing with new modern structures.
How was the work done?
The works were programmed for a three-year period. Seepage risk analysis were undertaken, the data from which ensured only targeted interventions were delivered since wholesale replacement of assets wasn’t viable.
At any one time, the team had up to three live sites running simultaneously while scoping and designing other work fronts during live construction.
The same core site team was responsible throughout, which helped meet the programme due to the familiarity and consistency it allowed.
The team identified potential for environmental harm so various types of monitoring were carried out, including:
- Sound and vibration monitoring on all piling to ensure safe limits were respected.
- Dissolved oxygen monitoring when working within the watercourse.
- Water level monitoring to combat any potential flood events.
Safety was a priority at every site. Over 4,000 positive interventions were reported and were one of the reasons zero reportable injuries were recorded during the duration of the project.
The team also prioritised mental health. During the project, the team got involved with the charity MIND and dedicated a display on site to create a space people could donate and educate themselves about mental health.
Difference the project has made
Apart from providing flood protection for an estimated 4,000 households, the project gave back to the community by replanting trees in the local area.
The team also donated a water cooler to Lincoln Christ Hospital School as part of their ‘increase drinking water/reduce single-use plastics campaign’.
To benefit the local economy, the team worked with local subcontractors in their supply chain. This also reduced carbon emissions from travel.
Materials were sourced locally, including aggregates from nearby quarries, concrete from the city centre, as well as many other miscellaneous items sourced from the region.
The team actively sought to reduce carbon throughout the project. When planning the sluice gates refurbishment, they identified ‘hot spots’ within the operational maintenance of the gates, at over 11,000tCO2e.
They proposed to replace the gates instead, for almost the same cost, but achieving a 93% reduction in whole life carbon.
Further carbon savings were made at Witham Walls where the team re-used and refurbished many existing materials – achieving a whole life carbon saving of 47%.
People who made it happen
- JBA Bentley and Environment Agency
