A picturesque pond in the heart of Carshalton became a wildlife graveyard after water was diverted to the River Wandle.

Concerned residents alerted councillors and the Environment Agency (EA) after water levels dropped and dead fish were seen in Carshalton Pond on Friday, March 31.

By Sunday (April 2) the situation had worsened and many parts of the pool had dried up completely before people arrived to assist birds that were nesting nearby by moving them away from the site.

Sutton and East Surrey Water (SES Water) said it was under licence to keep the Wandle flowing to sustain wildlife living in, or near the river, and as a result, diverted the flow from the pond directly to the stream. It added that cracks in the edges of the bottom of the ponds meant water seeped into the ground before it reached the lower parts of the pool and the Wandle.

Works to repair the cracks will take place throughout the week after which the ponds will be refilled.

Residents voiced their concern over the situation on the Wallington Facebook group shortly after the pond was drained.

Neil Blackwell posted: “I can understand the need for essential or emergency work if it’s required. What I don’t understand is the contempt shown by the council and the other agencies to the residents of our community by not informing us prior to this.

“A lot of people have been to hell and back this past weekend trying to sort this out. Totally disgusted with the London Borough of Sutton.”

Councillor Tim Crowley, leader of the Conservative opposition at Sutton Council, told the Sutton Guardian he did not understand why work was being carried out while birds were nesting.

He said: “It’s a very sad situation. I can’t understand why they are carrying out maintenance during the bird nesting season.

“Council officers were tetchy about it two weeks ago when I mentioned there were concerns over the lowering of water levels in Beddington Park. I was assured this would not happen and now it has happened to the ponds in Carshalton too.

“I would like to say a huge thank you to all those who came out and helped with the birds on Sunday and this undoubtedly made a terrible situation better.”

A spokesman for Sutton Council said: “SES Water have a licence with the EA to extract water from the North Downs chalk aquifer.

“When the aquifer is low and the springs are not flowing, they turn on an artificial recirculation system which pumps water from the Wandle, just north of Goat Bridge, up to Carshalton Ponds, which then replenishes the Carshalton arm of the river. Without this system, the Carshalton arm of the Wandle would be dry for much of the year.

“The last six months of 2016 were very dry with only two-thirds of the long term average rainfall being received. This means the groundwater levels are currently low for this time of year which has been a major cause of the Carshalton ponds becoming drier in recent weeks.

“There are also some cracks in the edges and bottom of the ponds, which means that when SES Water pumps water into the ponds, it seeps back into the ground before it can get out of the lower pond and flow down the Wandle.”