In our application for development consent this site connects the existing local combined sewer overflow (CSO), known as the Frogmore Storm Relief – Bell Lane Creek CSO, to the main tunnel. It is also used to drive a long connection tunnel southwards to King George’s Park and northwards to Carnwath Road Riverside, to connect the CSOs at Dormay Street and King George’s Park to the main tunnel. This long connection tunnel is known as the Frogmore connection tunnel.
The Dormay Street site comprises land within Thames Water’s ownership, part of the Frogmore Industrial Complex and Causeway Island (including part of the Wandsworth Depot,) as well as the use of a section of The Causeway running down to the junction with Dormay Street and Armoury Way. The location of the site is shown below.
Work includes construction of underground structures to connect the CSO to a shaft approximately 24 metres deep and with an internal diameter of approximately 12 metres. This shaft would be constructed within the site to the north of Dormay Street, and would transfer sewage flows from the CSO to the main tunnel.
While most of the operational structures would be underground, a combined ventilation structure and kiosk would be a permanent above ground feature.