Reducing storm overflows at Appley
We've prevented 87 storm overflow releases this year by upgrading our Appley Wastewater Pumping Station, quadrupling the available storage and doubling the flow rate.
The problem at Appley
Our Appley wastewater pumping station was struggling to cope with increasing rainfall, resulting in regular storm overflows from the long sea outfall into The Solent. Environment Agency permits set the rules for how our sites work, and when we investigated, we discovered that by challenging the permit, we could significantly increase the capacity of the site and reduce storm overflows.
Improvements to Appley wastewater pumping station
Following a consultation with the Environment Agency, we reconfigured the site, quadrupling the available storage from 900m3 to over 4000m3. We also doubled our flow rate from 110 litres per second to over 240 litres per second. These two improvements combined allowed the site to work much more effectively than before.
The result
Reduced storm overflows on the Isle of Wight
The improvements immediately started reducing storm overflows, with 87 releases prevented from going out into the environment this bathing water season (May 2024 – September 2024).
Protecting shellfish in the Solent
The shellfish bed which harvests oysters close to the outfall is now regularly achieving Class A water quality samples, the highest possible rating.
Future work
With our Appley site optimised to its maximum capacity, we must work with landowners, councils and highway authorities to manage rainfall runoff to stop it overwhelming the sewer system. This will involve green infrastructure such as swales, rain gardens and basins to slow down water or stop it reaching our pipes altogether.
Find out more about how our Clean Rivers and Seas Task Force are reducing storm overflows across our region.