Southern Water is securing Hampshire’s water resources via a new bulk supply of up to 15 million litres of treated water a day from Portsmouth Water and a scheme to build a strategic 18km pipeline to transfer up to 45 million litres of water a day from the River Test to the supply works in Otterbourne.

Between them, 680,000 Southern Water customers in the county, including in Southampton, Winchester, Romsey and Eastleigh, as well as the Isle of Wight, use an average of 144 million litres of water every day.

Currently, about 60 per cent of that water comes from the River Test and the River Itchen, with the remaining 40 per cent coming from underground aquifers.

The raw water is treated at one of two sites – Testwood Water Supply Works in Totton in the south and Otterbourne Water Supply Works in the north, before being pumped to homes via a network of more than 4,000km of water mains.

However, the Habitats Directive now limits the amount of water the company is allowed to take from the River Itchen in times of extreme drought to help protect the river’s ecology.

In October Southern Water volunteered changes to three abstraction licences that take water from the River Itchen to comply with the Directive. Some changes will be implemented soon but the main changes have been deferred, in agreement with the Environment Agency (EA), until December 31, 2018 to allow time for the company to implement replacement supplies.

The company said there is a need to balance the reduction in available supplies resulting from the licence changes with an increase in the amount of water taken from alternative sources, including the River Test, in order to maintain customers’ supplies.

The new bulk supply of up to 15 million litres of treated water a day from Portsmouth Water is being implemented to be used when required. Further resilience in times of drought will be provided by a project at Candover to top up the River Itchen with water abstracted from the chalk aquifer.

Central to the plans is a scheme to build an 18km pipeline to transfer up to 45 million litres of water a day from the River Test to the supply works in Otterbourne. The amount of water taken from the River Test will remain within our existing abstraction licence and will depend on demand for water.

The pipeline scheme and other projects are being implemented alongside ways of reducing water use – such as further reductions in leakage on the network and the roll out of metering which has already helped customers in Hampshire cut their water use by 16.5 per cent.

Southern Water is continuing to carry out environmental investigations along the proposed pipeline route across the coming year. Work on the pipeline itself is expected to start in 2017 and to take around 18 months to complete.

An Environmental Impact Assessment is continuing to be developed that will support the future planning application, which is expected to be submitted in late 2016.

Project Manager Damon Elliott said:

“It is vitally important that we strike the right balance between securing clean, safe water supplies for our customers and protecting the environment which provides that water in the first place.

“The pipeline between the River Test and the Otterbourne supply works is an essential strategic link which will make the network more resilient and flexible by allowing us to move water around the area more easily, especially during times of drought.

“We are continuing to work closely with a range of people on these projects, including local authorities, environmental groups and landowners and are incorporating their views and guidance into our plans.”

Abstraction licence changes for the River Test are under discussion with the EA and further joint work will be undertaken to better understand the ecological needs of the river and how to best manage these in balance with the need to maintain water supplies.