Innovative engineering solution up and running in drive to reduce Kent storm overflows

A major redesign of a wastewater treatment works near Whitstable in Kent is set to reduce storm overflows in the area by up to 30 per cent. 

The work at our Swalecliffe site is enabling the existing works to store much more stormwater in its pipes and tanks than ever before, meaning that wet weather will be less likely to overload the site – leading to a possible storm overflow into the sea, to prevent flooding of the nearby Whitstable community. 

Southern Water worked closely with the Environment Agency on the complex engineering solution, leading to a complete overhaul of how the site works, thanks to the installation of new chambers and pipework. 

This has created 1,800 cubic metres of extra storage capacity, allowing space for 450 litres of stormwater per second to be contained. Over the course of two hours, this is the equivalent of more than an Olympic-size swimming pool of stormwater, which would then be fully treated once levels drop. 

It is one of many measures that Southern Water is taking in the Whitstable area to improve its performance and reduce the number of storm overflows, such as installing 2,000 slow-draining water butts at homes near Tankerton Beach in collaboration with community groups including SOS Whitstable, and introducing sustainable drainage schemes and efforts to ‘green’ community spaces like Cornwallis Circle.  

In total, Southern Water is investing over £25 million on upgrades to the Swalecliffe Wastewater Treatment works, including the replacement of the storm overflow pipe. On top of this, further investment is planned in the local area to reduce and slow the amount of surface water entering the system in the longer term, with an announcement due later this summer. 

Southern Water’s project manager, Jon Yates, said: 

“We are under no illusions that our environmental performance in the Whitstable area must improve and this is just the latest milestone in the programme of work we’re doing to address storm overflows here. 

“It is really positive that the redesign of the Swalecliffe site is set to cut storm overflows by up to 30 per cent, but we are keen to press ahead and continue our work to increase this number with other measures we’re taking in the area.”