Water and Effluent Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/425132
10 WET NEWS DECEMBER 2014 The installation of precast components for the new service reservoir saved seven weeks in terms of time, and resulted in a capital efficiency claim of £743,000 3D technology key for SRE • Yorkshire Water has replaced its two Bram- ley Service Reservoirs (SREs) near Leeds with a single underground tank. No easy task, as it has been built on a quarry. Andrew Don explains. Y orkshire Water began an extensive programme of work to upgrade dozens of clean-water supply reservoirs across Yorkshire in 2010. The fa- cilities store treated clean water before they are fed to local homes and businesses in a fit state for drinking. The joint venture partners began the gargantuan task to create one of the county's larg- est underground reservoirs early last year in a feat of challenging engineering that took 18 months to complete. The project was regarded as a breath-taking undertaking, a sophisticated task that utilised the latest modelling techniques and technology available. Project manager Dave Ellis said at the time that Yorkshire Water was used to undertaking big construction products but the size of the tank it was build- ing at Bramley put the project in a different league to all the others. The scheme was part of a £23M investment that the utility had mapped out in the five years to 2015 to replace 16 Service Res- ervoirs (SREs). The two brick- built SREs that the new infra- structure was designed to replace at Bramley were built in the 1800s and early 1990s and had to be retired. Condemned A qualified civil engineer con- demned them under the Reser- voirs Act 1975 because of both the age and the condition of the brickwork in order to retain water quality and ensure secu- rity of supply. Both SREs could PROJECT SPECS • Design and build a new 16Ml service reservoir at Bramley to replace to existing SREs • Footprint: 56m x 69m. Height: 6m • The new SRE must serve nearly 30,000 properties • Max flow: 4ML per day THE VERDICT • The project achieved delivery of the required water quality to homes and businesses • The new SRE provided security of supply • Ensured longevity ONSITE SERVICE RESERVOIRS have collapsed, which would have had dire consequences for the communities they served Ellis explains that the exist- ing No 1 service reservoir had cracked column heads and the No 2 reservoir had "the poten- tial" for the roof to cave in. The two SREs were interlinked and problems with one of them had the potential to affect the other. "We condemned the first one and got rid of it and continued to use the second one, which was in the same condition but not quite as bad," Ellis says, "but the business made the decision to replace both with a 16ML [megalitre] new reservoir – the equivalent of six Olympic- sized swimming pools." Ellis says it was an easy deci- sion for Yorkshire Water to make. The new infrastructure would supply high quality drinking water to more than 27,400 properties across West Yorkshire once in service via the new tank, off Broad Lane – one of hundreds of supply reservoirs Yorkshire Water operates, most of which are underground. Many of these underground tanks, of varying size, have been in operation for 25 to 100 years. They are regularly main- tained but their lifespan is finite and the oldest have to be replaced to make way for new, stronger structures, which have the added bonus of further improving drinking water quality. "This new tank will boost the reliability of our vast water sup- ply network and ensure that customers in West Yorkshire continue to receive some of the best drinking water in the world," says Ellis. He calls it "an amazing achievement" because York- shire Water managed to take the old reservoir offline and bring the new one into service without any interruption to customers' water supply. Precast concrete The options for constructing the single replacement service res- ervoir were considered and Yorkshire water assessed whether to build the new one with in situ concrete or precast concrete. TECHKNOW • Three different types of excavation were used • Engineers had to tie into the existing apparatus connections • The reservoir was sized to ensure it would be big enough to fulfil its brief • Building Information Modelling software package used that generated and managed of digital representations • Revit, specifically built for BIM, added 3-D technology • Precast concrete prepared off-site created cost efficiencies and boosted safety and quality