The aim of this diversion was to reduce surcharging and backing up of sewerage within the existing system. It was designed to address flooding and water quality at Kinning Park Pumping Station, St. Andrews Road CSO, Aikenhead, Burnfield and other key locations.

Scottish Water determined, through the Glasgow Strategic Studies (GSS) Value Management process, that a new tunnelled sewer to relieve the existing South Side No.1 Sewer in Glasgow was the preferred strategic hydraulic solution to deliver regulatory drivers for the Shieldhall catchment. The new sewerage tunnel was constructed from Queens Drive through Queens Park, Pollok Park and Bellahouston Park, connecting into the existing network at Craigton Industrial estate adjacent to the Ayr to Paisley railway line.

The strategic tunnel comprised of a 5.46 km gravity sewer, with a nominal internal diameter of 4650mm. A total of 5No. 15,000 mm internal diameter shafts were incorporated along the route. The 5No. shafts formed part of the permanent works and acted as part of the storage of the system, which is approximately 90,000 cubic metres. The tunnel has been sized to convey the Dry Weather Flow (DWF) and provide an increased Peak Flow Factor (PFF) during storm conditions. The tunnel also provides a significant amount of online storage. No head room was included in the design of the tunnel.

The new sewer relieved the existing sewerage network and provided the necessary flow conveyance and storm storage. The upstream connection point of the new tunnel to the existing network was at Queens Drive, adjacent to Queens Park. From this point, the tunnel runs to the west side of Glasgow, tying into the network again at Barfillan Drive, Craigton Industrial Estate.

The scheme was assessed using CEEQUAL to Client & Design Award. The construction of the scheme was also assessed using CEEQUAL. On 7th October 2015 the Excellent Client & Design Award was presented to project team members.