By ashleykaren
Portsmouth Water has revealed that modified programs for a long-approved tunnel forming part of the £325M Havant Thicket Reservoir in Hampshire will postpone delivery of the eagerly expected project.
Ward & Burke, the civils company, was last year assigned to provide a 4.6km long bi-direction pipeline operating from Bedhampton pumping station to the submitted artificial storage lake close to the edge of the South Downs.
The scheme received the confirmation in October 2021, however, a consultation launched earlier this year set out submissions to change the route and use micro tunneling to decrease the pipeline length to 3km.
While the consultation document pledged that the overall timeline for the reservoir “remains the same” under the new plans, with work to construct the new pipeline due to begin in late 2023, Portsmouth Water has now conceded that the project will be finished “later than originally planned”.
Proposals depend on consultation and councilor permission, while required earthworks for the revised plan can only be undertaken in the drier months, and the reservoir can only be filled during winter.
Replacing an open-cut method initially suggested, the new scheme would see micro-tunneling employed to put in the pipeline majority, which would be constructed in sections through eight access shafts between 6m and 13m in diameter.
The utility said in a statement: “Our key priority is to minimize disruption to residents and the environment, while delivering the infrastructure needed efficiently and with value for money for customers.”
Portsmouth Water and Southern Water have also been investigating different programs to top up Havant Thicket Reservoir with recycled water, which would become achievable by the new tunneled pipeline.
The two-way pipeline could be employed by Portsmouth Water and Southern Water, as part of the Hampshire Water Transfer and Water Recycling Project, to pump highly-treated used water into the reservoir, increasing its chances of supplying customers during drought conditions.
The utility added: “A shared tunnel approach means that, if proposals for water recycling are agreed in the future, residents won’t need to experience additional disruption.”
“It will also reduce environmental impact and it’s estimated that taking this future proofing approach could save over £100M compared to installing separate new infrastructure at a later stage.”
When finally constructed, the reservoir will hold about 8.7 b. L of water and provide up to 21 ML of water daily.
It will be 1.6km from east to west and 0.8km from north to south, with a new wetland on its northern shore. It is being constructed on a 160-ha grassland site, owned by Portsmouth Water since the mid-1960s.
Earlier this year, a JV between Mackley and Jones Bros Civil Engineering UK received the contract to construct the reservoir, which will be the first built in the UK for several decades. Nevertheless, Portsmouth Water then announced it had ensured the cash required.
