Guernsey Water successfully improves wastewater drainage
This programme has reduced the risk of sewer flooding for customers and created capacity for future growth in wastewater flows and rainfall intensity. Climate change means that increased capacity is needed due to heavier rainfall in shorter spaces of time. Predictions show that there will be drier periods and wetter periods in any one year, so investment in sewer capacity has been planned for and invested in.
Stephen Langlois, Guernsey Water managing director said: "Water quality is vital for public health, so the team at Guernsey Water always strives to protect the water environment from source to sea. This major wastewater investment provides greater resilience to pollution of the marine environment from sewer overflows and helps to protect bathing water quality at Bordeaux".
The work comprised upgrades made to the 17m deep pumping station at the southern edge of St Sampson's Harbour. This station transfers sewer flows from large parts of the Vale and St Sampson's onwards to the wastewater centre at Belle Greve.
The main items of this phase of works included pumping station rehabilitation to reduce 'ragging' (choking) of the pumps and reduce future reactive maintenance needs. The team also replaced all three pumps with larger, more efficient, alternatives which pump greater volumes.
Part of the investment in HSS was to ensure that it meets health and safety requirements. Site safety has been improved by providing a bespoke man-riding cage for safer station access, upgrading the station surroundings, including the installation of hard standing for cranes, and security fencing around the site.
To carry out the works the station needed to be bypassed and isolated from existing sewer flows with temporary overpumping units which were in place for approximately 6 months.
Carl Falla, Capital Delivery Manager, said: "We're very pleased that the team achieved the wastewater catchment project's aim of reducing foul water flooding and preventing spills from sewer overflows. "We have already seen improvements in water flow levels and the works are a positive impact on the frequency of flooding."
The four-phase northern drainage project is one of the largest in Guernsey Water's business plan, with an investment of £5 million.