As the drought continues and the threat of a hosepipe ban looms, ponds are beginning to show the implications of below average rainfall this winter.

The Dew Pond in Nonsuch Park is noticeably low and Councillor Mary Burstow, the chair health and well being scrutiny committee, said it is the "canary in the mine" warning us that water levels are dropping.

She warned we need to start conserving water, and said: "Nobody would worry if this was happening in July, but in February this is really worrying."

The pond is a bourne, where an underground stream comes to the surface, and it is part of a line of bournes which run through the chalk.

The lack of rainfall means that the stream has not been replenished.

Mrs Burstow said: "If you talk to local people they will tell you how in the past this bourne was so full, the water lapped up to the meadow.

"It has not been at those levels for over three years."

The trees are starting to feel the effect of the lack of rainfall and Ben Morris, the borough’s Arboricultural Officer said: "The lack of available water can cause stress in trees.

"If a tree is under stress then it can be vulnerable to other agents that cause harm including fungal or viral infections.

"Water stress can cause the stomata to close, thus affecting photosynthesis."

Photosynthesis produces carbohydrates which are used as energy store.

If there is no energy, there is no active defence, no growth and the trees can become weak and die.

Mr Morris added: "Some trees are more prone to water stress than others; a lot of our indigenous species are used to a certain type of environmental condition and are not good at adapting.

"It is something that we consider when looking at the type of species we plant."

Stuart Hyslop a spokesman from Sutton and East Surrey Water said: "The situation with this pond is an example of how little water there is in the environment."

The lack of water means there is very little water in underground aquifers feeding ponds, streams and rivers.

Mr Hyslop added: "It’s a reminder that we need to do all we can to save water."

For more information on how you can save water visit Sutton and East Surrey website waterplc.com/pages/home/saving-water/.