Sutton Council says a damaged plug in the upper pond is only part of why Carshalton Ponds drained. Contractors return next week; a carp has been moved to Beddington.

A damaged plug in the upper pond is not the whole story behind the sudden draining of Carshalton Ponds, Sutton Council says. The problem is “complex and likely due to more than one reason”.

The council gave the update on Friday 30 October, two weeks after the ponds emptied overnight. Contractors will be on site next week for more detailed investigation works.

The water rose again after the rain earlier in the week. The council says the levels have since dropped again.

What the council has said so far

The council has published four updates on its Carshalton Ponds news page:

Date What the council said
17 October The ponds drained overnight and the cause was being investigated
20 October SES Water had stopped topping the ponds up late the week before; the council did not know why levels fell so far, so fast
23 October Investigation works started; initial findings suggested one of the underground plugs was damaged
30 October The plug damage is “obvious”, but the scale of the loss from both ponds points to more than one cause

Why the ponds depend on topping up

The ponds are fed by local springs, which are seasonal. The water reaches the ponds through a network of pipes. When the springs are dry, SES Water tops the ponds up.

That stopped about two weeks ago. The council says SES Water halted the extra pumping because of the Environment Agency’s national drought restrictions. Even so, the council said on 20 October that it “would not expect the levels to drop as dramatically and as quickly” as they did.

This week the council worked with SES Water “to better understand some of the technical issues”. The aim of next week’s works is to confirm why the levels fell so quickly once the pumping stopped.

The wildlife

The council calls the wildlife “a primary concern”. It says it is:

  • monitoring the ponds with local groups, including the Swan Sanctuary
  • talking to the Environment Agency about the welfare of the fish
  • keeping notices up around the ponds for anyone who sees wildlife in distress

A carp spotted in the ponds on Friday was moved safely to the lake in Beddington Park. No other fish were found.

What it means for you

  • If you see a swan, duck or other animal in distress at the ponds, follow the notices on site. The council says they are there for exactly that.
  • There is no date for a fix yet. The council says the investigations will inform “proposals for sustainable solutions”, and that it will update when it knows more. We will add each update here.
  • The ponds remain dependent on rain and the springs until the leak is found, so expect levels to rise and fall with the weather.
  • The drought has not ended. “We are still officially in a drought at the start of November,” the council said in its Even Greener Borough call for views, also published on 29 October.

Things to do nearby, including the Honeywood Museum beside the ponds, are in our Sutton what’s on guide.

Sources