Thames Water - Chesterton Farm infrastructure renewal

Background

As urban populations grow, existing infrastructure can struggle to keep up
with demand. On the outskirts of Cirencester, a major new housing
development was built, including 2,350 new homes and associated facilities,
but with an insufficient foul sewer network to accommodate the population
increase.

The project was particularly challenging due to a high ground water table,
hard ground, large diameter sewers in deep excavations (up to 5.4m), and
the pipeline had to cross multiple obstacles such as a quarry, abandoned
canals, and railways.

Solution

To support the new housing development, the Infrastructure Alliance (IA)
composed of Clancy and Kier Group was tasked to construct a new 3.7km
gravity sewer and pumping station to support the future growth of
Cirencester.

The new infrastructure transfers flows from the development and Cranhams
Pumping Station directly to the Cirencester Sewerage Treatment Works. To
support projected capacity increases, 13% of manholes have allowance for
future connections.

Benefit

With a working relationship spanning 30+ years, Clancy were well
established to undertake the project. Two years prior to works starting on site
Clancy engaged with both Thames Water and the designer to develop
optimum solutions.

Clancy used innovative techniques such as micro-tunnelling and guided
auger bore to cross difficult ‘no-dig’ obstacles. Using the UK’s largest GPS
controlled trencher to cut up to 3.6m x 1.1m trenches through hard rock,
Clancy also ensured speed, accuracy and safety. The innovative ‘PipeMac’
was deployed for the first time in the UK and delivered a step-change in site
safety.