Guernsey Water Annual Report 2016

Guernsey Water 2016 Annual Report SUFFICIENT AND RESILIENT water.gg/ annualreport2016 17 pipes made of this material due to their age and fragility. St Saviour’s dam (parapet wall maintenance) We worked with local contractors and specialist advisors to repair cracks in the parapet wall along the dam walkway at St Saviour’s reservoir. While the weathering of the walkway and parapet walls has no implications for the integrity of the dam itself, these repairs avoided greater deterioration of the dam structure in the longer term and have extended the life of this critical asset. Water network modelling We have developed a hydraulic model of our water distribution system which has improved our understanding of how it performs. This enables us to test improvements to the system and helps us plan for and deal with emergencies. Business Performance Unplanned water supply interruptions We had 40 water mains bursts in 2016; although a small increase on the 38 bursts we had in 2015, water supply leakage and burst mains remain low. We have also continued to minimise the impact of these bursts on customers; in most cases our distribution team rapidly deployed temporary supplies to reduce the amount of time their water supply was interrupted. This was tested when one of our critical water mains burst on 13 April in Rue du Dos D’Ane, which resulted in widespread low pressure for customers and a number of discolouration complaints once supply had been restored. Our new customer liaison team supported the customers affected. Throughout the year the average monthly number of interruptions as a percentage of customer supplies 5 was 1.4%, which is an acceptable performance 6 but means we missed our target of 0.5%. This was solely due to the Rue du Dos D’Ane burst, as this alone meant the target for the year could not be recovered. Business Initiative Description Target Date 2016 Progress Performance Develop a Water This plan will help us determine 2016 – 2017 Phase one completed on time, the cost benefit Resource how we meet the long-term of using Les Vardes Quarry for water storage Management Plan water demands of our island. will be assessed in 2017. Usable water investigations A sedimentation survey of our 2016 – 2017 Bathymetric surveys of our six largest water storage St Saviours reservoir and water reservoirs were carried out to confirm their storage quality survey at different depths capacity. Analysis of the depth profile of water quality of our Longue Hougue reservoir. at Longue Hougue is ongoing. Develop a Drought Plan The plan will determine how we 2016 – 2017 Action levels for drought management determined. deal with drought and assess the Analysis suggests that drought measures could risk of water use restrictions. reduce the risk of hosepipe/sprinkler bans to 1 in 20 years. The feasibility of these measures will be tested in the next phase of this work. RawWater Strategy We will invest in refurbishing and 2016 – 2017 We planned to commence three schemes in 2016 extending our network of raw but only the relining of our raw water transfer water pipes. main between Longue Hougue and Juas reservoirs has started. Bursts on our Moulin Huet and Vale Pond transfer mains has increased the importance of progressing these schemes in 2017. Develop an Integrated This strategy will determine how 2016 – 2018 A surface water management policy for the adaptation Drainage Strategy we manage all our drainage of our drainage systems to climate change has been assets in the short to long-term supported by the States’ Environment & Infrastructure Committee. A sustainable drainage exemplar project has been completed at Vauvert Primary School. Development of Emergency We will develop response and 2016 – 2019 A hydraulic model of our water supply network has Response & Recovery Plans recovery plans for our critical been completed and is now being used to understand assets using our hydraulic the impact of critical asset failure. Mitigation measures modelling. and emergency response plans will be developed in 2017. 3 3 3 3 3 5 In accordance with Ofwat serviceability measure this is weighted according to the length of interruption. 6 Good (<0.5%), Acceptable (0.5 - 2.0%), Needs Improvement (>2.0%). ! Business Initiatives ! 3 5 On Target = Satisfactory progress but not all 2016 tagets met = 2016 targets missed = We now understand the level of drought protection we can provide for our customers and how to deal with drought.

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