Southern Water
Locaton: St Mary Bourne, Hampshire
Technique: EcoCIPP Lining
Main Contractor: 4 Delivery
As part of an alleviation scheme by Southern Water, Perco recently installed 7km of EcoCIPP lining to prevent groundwater ingress.
Extended periods of wet weather raise the groundwater levels and water gets into the sewer system. The downstream pumping station couldn’t cope with the resulting flows, so the water company had to tanker the flows away, at times on a daily basis.
Whilst much of the 8.2km long sewer was in good condition, survey work and computer modelling by 4 Delivery, Southern Water’s framework contractor, showed significant groundwater ingress at the privately-owned house connection laterals. Southern Water decided to rehabilitate the majority of the clay sewer by GRP lining and replace pitch fibre sections completely.
Perco began work in late January, with 5km of 225mm diameter and 2km of 150mm diameter EcoCIPP lining installed by the completion date in June. A robotic cutter opened up 160 laterals along the route.
Some of the sewers passed through fields but most manholes were in the middle of the road, creating access difficulties. Perco set up traffic management and worked closely with 4 Delivery, who organised road closures, diversions and tankered flows away during the lining operation.
The existing 25” cast iron rising main carries sew...
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