Plans submitted to build 22km pipe to secure water supply

Plans have been formally submitted for a 22.8‑kilometre underground water pipeline linking Andover and Winchester, in what Southern Water says is a critical step to secure future supplies and protect some of Hampshire’s most sensitive chalk streams.

The scheme, known as the Andover Link Main, has been lodged with both Test Valley Borough Council and Winchester City Council as duplicate planning applications.

Southern Water says the project is needed to strengthen the resilience of the county’s network during drought conditions, and to enable the company to reduce the amount of water it takes from the River Test and River Itchen, both of which are internationally important chalk rivers.

In a planning statement, Adams Hendry Consulting Ltd said: "The Proposed Scheme is needed to build resilience in the water sector and address pressures on water supplies by linking SWS’s strategic water supply networks of Winchester and Andover."

The location of the 22km pipe (Image: Southern Water / WSP Binnies)

It adds that "the South East of England is water stressed", meaning less water can be safely abstracted in dry periods.

The pipeline would run from Crab Wood Water Service Reservoir, west of Winchester, to Micheldever Road reservoir, on the southern edge of Andover.

Treated water would be moved between the two supply zones so Andover can draw on alternative sources during droughts.

The statement by Adams Hendry Consulting added: "During a drought event the Andover area is not directly linked with any other areas of SWS supply."

Most of the pipe would be installed through open‑cut trenches, although a number of sensitive or strategic locations would be crossed using trenchless tunnelling.

This includes a 415‑metre section beneath the River Test and a 272‑metre crossing under the River Dever and Bransbury Lane. Six major trenchless sections are planned in total.

Construction would take place around three years, with works expected to begin in Autumn 2026 and the pipeline entering service by Spring 2030.

At peak, the project is forecast to generate 182 vehicle movements a day, and several local roads, including Dean Lane and part of the B3049, would need to close for up to one week each.

The statement acknowledges some environmental disruption, including the removal of eight trees, partial removal of 24 tree groups, and 33 hedgerows, the majority classed as “important”.

All vegetation will be reinstated, and Southern Water has committed to delivering at least 10% biodiversity net gain.

Once completed, the pipeline would operate largely unseen with it intended to remain in use for its full 100‑year design life.

At the time of reporting, no public comments have been made on the planning application.

The determination deadline for the plans has been set to Wednesday June 17.

To view the planning application in its entirety, visit the TVBC planning portal on: 26/00378/FULLN.