A major growth in demand for water fuelled by plans for new homes in Gillingham and Mere is set to put even more pressure on the area’s chalk streams, says a local action group.

The Mere Rivers Group says that the water levels and flow of Shreen Water and Ashfield are already lower because 9 million litres of water and being pumped each day by Wessex Water from the Mere area to supply residents in Mere, Gillingham, Marnhull, the Stours and elsewhere. But plans to build around 1,800 homes in Gillingham and at least 130 new houses in Mere are set to push demand even higher.

Water usage in the area has grown significantly between 2011 and 2017, with demand in Gillingham up by 16.6% to 2.8 million litres a day, Mere up 5.7% to 740,000 litres, Marnhull and Kington Magna up by 24% to 670,000 litres, while only the Stours have recorded a decline, down 5.5% to 340,000 litres.

Brett Norris, the group’s vice-chairman, told its AGM last month: ‘At a very conservative estimate the extra water needed to supply these new homes based on Consumer Council for Water figures will be an additional 534,000 litres a day.’ He continued: ‘If nothing is done the small rivers will dry up and the water quality in the larger rivers will deteriorate. The cost of supplying water will increase and basically our bills will go through the roof.’

Mr Norris, who is also a local councillor, warned that lower flows in the streams would not just affect Mere but other towns too. He said that the clean spring water from the chalky Mere streams currently helps dilute the agricultural waste and effluent that goes into the rivers downstream, but if the springs fail the River Stour – which meets the Shreen in Gillingham – would be affected. ‘With the streams drying up, the water getting down to Gillingham would be polluted as well,’ he said. ‘The ecosystem in the river will start to fail.’

Adrienne Howell, another member of the Mere Rivers Group, which was founded in 2011 after a dry summer dried up the local streams, said developers did not appear to understand the impact of growing water demand. She said she and chairman Ian Sheppard went to the public consultation over the plans to build 1,800 homes in Gillingham and asked a developer where the water for the new houses would come from. ‘“From Wessex Water”, he said. But where is Wessex Water going to get it from? They don’t have a clue of the problems involved.’

Ian Sheppard said another key issue was that around half of the 9 million litres Wessex Waters abstracts from Mere is sent elsewhere. ‘It makes me very cross when they take water from us and send it to Yeovil when they don’t need to,’ he told the meeting, pointing out that the attraction of Mere’s water to the company is that it does not need much treatment.

‘Mere water is clear, Mere water is clean, Mere water is cheap and they are running a business,’ he said. ‘We know that the problem is over abstraction,’ said Mr Sheppard, whose group is pushing for water-saving measures to be installed in new homes and for the 9 million litre daily abstraction of water to be reduced. He said that if the streams ran dry it would ‘kill our environment’.

Gillingham councillor David Walsh, portfolio holder for planning at North Dorset, told the AGM he had been unaware of the impact on Mere’s streams caused by the abstraction. When dealing with planning issues such as the new homes in Gillingham, they had simply consulted with the Environment Agency. He promised he would now raise the issue with government ministers. ‘I will champion this, I will take this forward for you,’ he said. Belinda Ridout, mayor of Gillingham, told the group: ‘I now really appreciate that the health of our rivers in Gillingham depends very much on the health of your rivers here and I will certainly take it to the town council.’

A spokesman for Wessex Water said: ‘We’ve listened to the concerns raised by the Mere Rivers Group and we constantly monitor the water resource position.’ He said they were trialling a system called ‘abstraction incentive mechanism’ (AIM) which reduces abstraction when water levels are low and are planning to introduce in Mere a free ‘Home Check’ system designed to help consumers reduce water consumption. The Environment Agency said they were working with Wessex Water to control the amount of water abstracted in Mere.