This project was based at a Reservoir capable of storing 1,040 acre-fee. The Dam’s auxiliary spillway had suffered a serious incident after almost a week of intense rainfall, which had an estimated annual exceedance of 1% (i.e. a return period of 100 years). As a result, a £15 million restoration project was needed.
ChallengeA top tier contractor was asked to carry out permanent repairs which involved the construction of a new side channel weir, ‘tumble bay’, spillway channel and stilling basin. The damaged auxiliary spillway would be removed, the dam repaired and the slope grassed over. For this to be completed, a number of excavations and piling works had to be undertaken. The excavations would require dewatering due to the high water table on site and also a water management system was required for surface water runoff to prevent contaminated runoff water from entering the nearby river.
SolutionGiven the importance of the Dam, and the sensitive nature of the surrounding site environment, RVT had to move quickly and get the right solution in place. RVT promptly attended site, took and analysed water samples and combined the sample information with the geological nature of the ground. As a result, RVT proposed a complete EnviroHub® chemical dosing water management system. This included EnviroHub® TU02 Dosing Skid, EnviroHub® TT10 Treatment Tank and EnviroHub® HL50 Lamella Plate Settlement Tank. The EnviroHub® system was able to achieve a particulate removal rate of around 95%. The system accomplished this by the neutralisation of colloidal (fine/clay) particles, allowing them to agglomerate together forming heavier flocs, which then easily settle out in our EnviroHub® Lamella Tanks.
