A major Cardiff engineering project designed to protect parts of the city from rising water levels could finish almost a year behind schedule and £10m over budget, according to new council documents.
In June 2021, the city’s cabinet approved the Cardiff Coastal Defence Scheme to protect against rising sea levels and erosion from Tidefields Road to the Rhymney River estuary and Lamby Way. The approved budget was £35,937,193, with 15% of funding coming from the council (£5,390,579) and the rest from Welsh Government (£30,546,614).
Costs rise to £45.5m
Documents presented before the council’s environmental scrutiny committee now show a different forecast. The total cost of the scheme could rise to £45,478,172, an increase of £9,540,979.
While the Welsh Government contribution is expected to stay the same, the extra £10m is expected to be a sole council contribution. Additional costs were generated due to delays, the “rock armour design” having to be revised due to “unsuitable ground conditions”, and a “revised piling solution” being required to avoid closing Lamby Way.
Delays and revised timeline
Planning documents state: “The council capital programme approved in March 2026 included £10m additional borrowing towards the additional costs identified, comprising £7m in 2026-27 and £3m in 2027-28.”
Other documents outline an estimated 285-day delay in completing the project. The contract for the defence scheme began on October 9, 2023, with an original completion date of October 31, 2026. This has now been pushed back to August 12, 2027.
Documents state: “The award of the construction contract was required to ensure we received the Welsh Government funding. Although delayed for as long as possible, the contract had to be awarded before the approvals from National Resources Wales and the necessary permission from the minister for regulatory environmental were received. The contract therefore commenced at risk before environmental permission was given. The delays to the approvals meant significant delays to commencement of work by the contractor. This increased the programme by 270 days.” No explanation was given for the additional 15 days.
