Scottish Water has begun a major investment in its waste water infrastructure in Paisley which will improve the water quality and natural environment in two local rivers.
The £17m project includes the construction of a one mile–long sewer, or waste water tunnel, under the streets of Paisley and the installation of Combined Sewer Overflows (CSOs) in the town centre.
These will substantially reduce the frequency of spills from the sewer network into the Espedair Burn and White Cart Water in storm conditions.
The investment, which is the biggest of its kind Scottish Water has ever made in Renfrewshire, is part of the company’s £250m, five-year programme of work, launched in 2013, to improve river water quality and the natural environment and tackle flooding across the Greater Glasgow area.
The overall investment, which includes the Shieldhall Tunnel in south west Glasgow, is the biggest in the Greater Glasgow area’s waste water infrastructure in more than a century.
The project in Paisley, which started on 10th October should take two years to complete. This will improve the river water quality in the two watercourses and, in turn, the River Clyde.
Contractors Amey, working for Scottish Water, will construct a large diameter interceptor sewer which will start at Bridge Street car park and go across the Watermill Hotel car park and Lonend before going along Saucel Street, beneath Saucelhill Park and the railway line near Canal Street Station, Espedair Street, Rowan Street and Kilncroft Lane/Neilston Road.
A new large, powered screen CSO will be installed on the opposite side of the White Cart Water from Paisley Abbey.
Another CSO will be installed at Causeyside Street/Forbes Place, opposite Dunn Square.
The new sewer will prevent spills by intercepting the overflows from CSOs currently spilling to the Espedair Burn. It will then transfer these flows downstream to the new CSO being built near Bridge Street/Mill Street. The sewer will, therefore, completely remove the spills from the Espedair Burn.
The new infrastructure will fundamentally alter the performance of the drainage catchment in Paisley and retain a lot more of the storm flows in the sewer network, which ultimately go to the Laigh Park Waste Water Treatment Works, meaning storm spills to the White Cart Water will also be substantially reduced.
The new stretch of sewer will have a diameter of up to 1.5 metres and will be installed at depths of between 4m and 20m.
It will be installed using the ‘closed face’ method, with pipe-jacking used to install the pipes behind a Microtunnel Boring Machine (MTBM).
A total of 15 shafts will be installed along the sewer route, with the MTBM tunnelling between them.
This method will be much more efficient and less disruptive than using the open cut method of excavating, given the depths of the pipe and the urban location.
Microtunneling is a trenchless construction method used to install pipes under ground.
It is a remotely-controlled, guided, pipe-jacking operation that balances groundwater and earth pressures.
The route of the sewer tunnel was chosen to minimise any disruption to local residents, road users and businesses.
Amey will also be installing a launch chamber and diverting two water mains before the main work starts.
The work will start in the town centre. There will be some road traffic management required during the project and details of this will be confirmed in advance.
Mrs Joanna Peebles, Scottish Water’s regional communities team manager, said: “This important project will significantly improve the environment on the White Cart and the Espedair Burn and, in turn, the River Clyde.
“Scottish Water has liaised with all relevant organisations and stakeholders, including Renfrewshire Council.
“We can assure local residents, businesses and road users that we will do everything possible to minimise any disruption and would stress that any inconvenience will be far out-weighed by the long-term benefits to the local environment that this investment will deliver.”
The improvement work in Paisley is part of Scottish Water’s £250m investment in the Greater Glasgow area’s waste water network, the biggest in more than a century, which will improve river water quality and the natural environment of the River Clyde and its tributaries, enable the area to grow and develop, alleviate sewer flooding and deal with the effects of increased rainfall and climate change.
The Greater Glasgow area investment follows years of collaboration and studies by the Metropolitan Glasgow Strategic Drainage Partnership (MGSDP), whose partners include Scottish Water, the Scottish Environment Protection Agency (SEPA), Glasgow City Council, Renfrewshire Council and Scottish Canals.
More information on the investment is available here.