We tend to think of Carshalton Ponds as a permanent feature of village life. The water flowing through The Grove feels as though it has always been there and always will be. But the reality is very different.
Today, the ponds continue to receive water from natural springs and rainfall, but they are also supported by water near the Beddington treatment works. This water is pumped from a dedicated pumping station at the corner of Watermead Lane and Goat Road.
The water is pumped via steel pipes 1.5 miles as a crow flies to the ponds and takes 30 minutes to reach there. It then takes circa 3 hours for the ponds to noticeably fill. This water is then pumped back up again. Several important rivers use an augmentation system such as this.
Water levels are monitored at a small measuring weir below the cascade in The Grove, helping to ensure the ponds remain healthy and full. The pumps come on when the level fall below 4.5ml/d. This stands for Megalitres (1 million litres) per day.
Looking after the ponds is about more than maintaining a picturesque view; it is about safeguarding a landscape that generations of residents have enjoyed and that future generations will hopefully continue to cherish.
Optional extra reading: The augmentation system was one of the first in the country, and set up circa 1968. At this time the ponds were also lined with concrete. The system was designed to protect the rare chalk stream of the Carshalton branch of the River Wandle. Due to continued abstraction for new homes the water levels in the natural aquifiers would become dangerously low.
An agreement was reached with Sutton District Water Company and Thames Water Authority (currently Sutton and East Surrey water company) that they could continue to take water from natural aquifiers. But the license stipulated that they also had to keep the ponds and surrounding streams topped up, provided the system was mechanically maintained.
They did this by taking some water from the Croydon arm of the Wandle. The water which flowed through Beddington Park is sand filtered and pumped to the ponds.
Overall this critical process helps maintain the habitats and wildlife that have relied on the river for hundreds of years.
© Copyright Secret Carshalton. With thanks to Norman Jones who is a volunteer at Spencer Road Wetlands for his valuable input in this story, and in details contained in Section 4 of the River Wandle Catchment Plan. Photos and diagrams by Secret Carshalton. Compiled and collating research by Secret Carshalton. Top image from when the upper pond was drained for leak repairs in July 2026. Kindly ask permission and credit sources before using this information.
And this is what nearly 30 years of silt looks like at Carshalton Ponds
🎥 Video: Carshalton Ponds completely empty during October 2023
Should we protect this system? Or would you rather it remained empty most of the time?