CRL develops innovative solution to prevent scour
CRL currently holds a Framework agreement with SSE for carrying out various works on their concrete structures. This was a small project carried out under this framework.
The works were required, after an inspection by SSE’s dam engineer, to prevent scour downstream of the small dam that diverts water from Loch Cuaich into Cuaich Power Station via an underground and overground steel penstock.
The works involved extending the concrete aprons which protect the embankments on the lower face of the dam. In times of high water levels, a significant quantity of water spills over the dam and without protection the embankment material on either side of the dam could be subject to scour and this in turn could compromise the stability of the dam.
Through a ECI mechanism, CRL worked with SSE to develop a solution for this problem with the main issue being the remote location of the dam. Initial concrete works had been carried out using helicopter deliveries as none of the access bridges could take the weight of concrete trucks and even if they could, the nearest concrete plant was over two hours from the site. The apron works required roughly thirty cubic meters of high quality concrete and CRL proposed the use of dry spray concrete to create these aprons as the materials could be easily delivered to site with pallets of bagged materials being transported to the dam site using a tractor and trailer which was able to navigate the river fords that are adjacent to the small bridges. This also made tying the new apron slabs into the existing slabs and the lower protection gabions much easier as the nozzleman could easily shape the new concrete to match the existing profiles.
On completion of the works the SSE dam Engineer revisited the site and was very happy with the finished aprons and commented that this could be a good solution for several other remote sites within the SSE hydro system.