WET News

Caption if needed sdkvjb sdkvjnsdlk dvsdvdvsdvsdvsdv dv skjbdv lskdjvbsdkljvbsdkv ONSITE TANKS AND STORAGE 14 WET NEWS DECEMBER 2018 | wwtonline.co.uk reservoirs manager, says. "The infrastructure was over 100 years old and, while it had served us well, it had served its time. "It was a mass concrete ser- vice reservoir with a part-height division wall, which meant you lost three-quarters of your capacity on draining down, and it had a shallow barrel-vaulted roof of very limited load-bearing capacity. In addition, the outer walls had cracked at a higher level, which meant we were only able to partly use the capacity of the reservoir so, while on paper it was a 128Ml reservoir, effec- tively we'd only got use of 120Ml." The plan to replace it with two reservoirs was not only deemed the most cost-effective but also means far greater ease of operation into the future. "With all service reservoirs, you need to be able to drain them down to inspect them and clean them routinely – generally between a seven-year and 10-year programme of clean- ing," Hope adds. "You need more operational flexibility than we had on the old reser- voir. It was a major inhibitor to operations during that time of inspection and cleaning, and we needed more cells that we could play tunes with basically." Severn Trent opted to com- petitively tender the project to drive value, and the result was a fully integrated joint venture between nmcn and Laing An aerial view of Ambergate Reservoir Reservoir renewal • Laing O'Rourke and nmcn (formerly NMCNomenca) this year completed work on Severn Trent's £43 million project to replace the service reservoir at Ambergate, delivering increased capacity and operational flexibility on a tight budget and a tight timeframe C ommissioned in 1907 and completed in 1910, the original Ambergate Reser- voir had helped supply water for people in parts of the East Mid- lands' biggest cities for more than 100 years, but by 2008 it was nearing the end of its natu- ral life. A high-level horizontal crack around the perimeter walls, dat- ing from the early years of the reservoir's operation, had lim- ited the reservoir's capacity appreciably. Furthermore, dete- rioration in the condition of the roof slab had rendered it unsafe to work on, and ancillary struc- tures were in poor condition. maximum capacity possible for the available land adjacent to the existing reservoir; the sec- ond phase involved demolish- ing the original reservoir and constructing a 50Ml single-cell reservoir in its place, bringing the total capacity up to 137Ml. The project, led by nmcn and Laing O'Rourke under the One Severn Trent banner, was com- pleted this spring a™er four years at a total cost of £43 million. "Ambergate Reservoir sits on the Derwent Valley Aqueduct and supplies water to customers in the East Midlands," Ian Hope, Severn Trent's dams and Operated as a single cell with a reduced 120Ml capacity, Ambergate was posing prob- lems in terms of operation, cleaning, inspection and main- tenance, and due to its critical importance to the water supply system, it could only be taken off-line for a few days at a time. Severn Trent, taking into account years of studies, deter- mined that the best solution was to construct two new reser- voirs on the existing site in Derbyshire. The first phase of the project would see the construction of a reservoir consisting of two 43.5Ml cells, representing the Helen Miles (left) and Cllr Margaret Lane (right) celebrate the conclusion of the project

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