Water & Wastewater Treatment

12 | january 2014 | WWT | www.wwtonline.co.uk Project focus P ipeline Condition Assessment within dams is essential, but very tricky. The risks associated with any pipeline can be seen as the product of the likelihood of failure, and the consequences of such a failure occurring; within the structure of a dam, if there should be any failure of large diameter pipework, the consequences can be particularly far reaching. Dams contain an array of pipes which can be used for a range of functions, varying from hydroelectric power generation through to water supply and reservoir level maintenance. The pipes are o•en located in confined spaces and may pass down sha•s or through walls. MWH's pipelines team recently tackled a project to survey the pipework in Severn Trent Water's (STW) 70-year-old Ladybower Dam – immediately below the site of the historic training runs for the World War Two Dambuster pilots. Such assessments will inevitably form a necessary part of managing one of the most critical asset types within the UK water industry. Indeed, Dams and Reservoirs Manager, Ian Hope, made clear that commissioning this pipework survey was part of STW's pro-active approach to reservoir ● Vital pipeline survey required at 70-year-old Severn Trent dam ● Pipes beneath two draw-off towers presented access constraints ● Electronic sensors established detailed picture of pipe risk safety. "We are not waiting to be confronted with imminent failure or indeed mandatory safety measures following a statutory inspection. The whole thrust of our approach is to better understand the condition and performance of our assets." Severn Trent approached MWH with a specific brief: The clay core embankment dam featured two draw-off towers with four draw-off pipelines in each tower; one high- level pipeline, one mid-level pipeline, and two low-level pipelines (a bottom draw-off and a scour line). The two low-level pipelines in each draw tower extended along below ground service tunnels, approximately 150m in length, delivering reservoir water to the downstream control houses By AdriAn dAvies-JordAn pipElinES EnginEEr, MWH ● sTW's pro-active ap- proach to reservoir safety ● Long term security of supply ● designing out the 'sin- gle point of failure' ● Health and safety of dam operatives • Drivers Pipes and pipelines A challenging pipeline assessment at Ladybower Dam a circular saddle was wrapped around the pipe so that its thickness could be monitored using the BEM sensor equip- ment. lines on the saddle every 50mm indicated where measurements were taken

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