SUPPLYING around 300,000 people in southern Hampshire, the River Itchen is a vital source of water in the county.

A classic chalk stream, the 28-mile stretch of water flows from mid-Hampshire to Southampton, rising near Alresford in the Hampshire Downs and flowing through Winchester and Eastleigh before discharging into Southampton Water.

There are currently no restrictions on how much water Southern Wa ter can take from the Itchen for public supply,but that’s about to change.

A new measure is being introduced to help protect the river and the species that live within it.

The Environment Agency has told the firm that if the flow rate of the river drops to less than 198 million litres per day, they are no longer allowed to take water from the river at their Otterbourne abstraction point.

It means that during a severe drought, Southern Wa ter would not be able to take water from the river to supply customers.

Because of this change, the company says that water resources in the Hampshire South region will fall into deficit if demand continues at the current level.

Souther n Wa ter adds that it would also affect resources on the Isle of Wight, who receive much of their water from the mainland.

And if there was a drought, restrictions would be introduced and could involve severe limits on what could be supplied.

However, the firm says the amount of water saved from metering, ongoing efforts to tackle leakage and a scheme to increase the amount of water that can be treated at Testwood Wa ter Supply Works at Totton, is enough to make up the deficit and meet projected demand during the next 25 years.