SOG-GW-T-HSS PS Improvements Phase II & III

Tender description

Harbour St Sampson pumping station (HSS PS) conveys wastewater flows from the north of the island to Belle Greve Wastewater Centre (BGWwC). It receives flows from the industrial and commercial areas of St Sampson and the Vale, and from surrounding residential areas. The gravity sewer system around St Sampson Harbour also receives pumped inflows from Lowlands and Les Landes Pumping stations. In addition, there is a major sewage cart emptying point on North Side at Griffiths Yard. The pumping station and catchment contributes to pollution risks from the combined sewage overflow (CSO) and there are associated sewer flooding problems which suffers from significant infiltration and tidal ingress. HSS has suffered with regular maintenance issues since its completion in 2001, and poses significant health & safety risks to the staff that operate and maintain it and continues to deteriorate. There are also resilience issues with the rising main that runs from HSS to Belle Greve Wastewater Centre (BGWwC) through the fuel storage facilities along Bulwer Avenue. This rising main burst in December 2014 necessitating a complicated and costly repair due to access difficulties and the constraints of working in this hazardous area. Addressing all of these interrelated issues without increasing the risk of flooding downstream of HSS is complex, but a strategy has been developed and delivery commenced in early 2016. These works, Phase II and III, are concerned with the sewer works required to divert flows away from an area which is at risk of flooding and increasing storage in the network during times of high flow. Keywords: Guernsey, HSS, States, Water, PS, Improvements