This ongoing work has identified a need to increase the storm capacity at Portswood. To do this, we’re going to build a storm shaft which will increase how much storm water we can store. By storing storm water in this way, we can treat it after the storm has passed and release it back into the River Itchen.
We work closely with the Environment Agency (EA) to understand exactly what’s needed to cope with excess flows during a storm. We do this by looking at long-term weather patterns, expected storm flows and population changes.
We’re starting work in February 2024 when we will set up our working areas within our site. Once complete, we’ll start construction of the storm shaft and anticipate it will be completed by summer 2025.
We’re installing a storm shaft with a diameter of 15 metres (m) and depth of 15m - 13m of which will be below ground. This shaft will store nearly 2.5 million litres of additional storm water (the same volume as an Olympic swimming pool) and pump it back into the works for treatment once the rain has passed.
Our work will involve installing sheet piles to hold back the surrounding ground and groundwater, so we can excavate to the required shaft levels. Once this stage is complete, we will install our precast segmental rings, building the shaft itself. Then, the inlet pipe and return pump, and the pipe arrangement will be installed within the shaft.
Our work will take place within the site. We'll do all we can to avoid unnecessary disruption to the local community.
We’ll need however to remove all excavated material from site using grab lorries. You’ll see these vehicles entering and leaving the site, travelling down local roads.
We estimate that during the peak of the construction, there could be up to 9 grab lorries a day entering and leaving site.
This is required due to the lack of space on site to store any excavated material. We'll also receive deliveries of equipment and materials during our work.
We’ll work with residents throughout construction, and we are open to any concerns/questions.
Please contact Matthew Thompson, Communication and Communities Lead for our contractor GTb, on 07810655423 or thompsonm@binnies.com, Monday to Friday, 9am to 5pm.
Alternatively, please call Southern Water, out of hours, on 0330 303 0368. Just tell us you’re calling about Capital Projects, with Project Reference Number (PRN) 751043, so we can help you more quickly. Or you can email us at capitalcomms@southernwater.co.uk.
Thank you for your feedback
Thank you to residents who took time to meet us at our customer event in January to hear and ask questions about the improvements we’re making at Portswood. We value your feedback. We are committed to working with you throughout the construction works in an open and collaborative way.