Hazelmere Dam (2)
In 2011 the Department of Water and Sanitation (DWS) appointed Ingérop South Africa (ISA) as Consulting Engineers for the Raising of Hazelmere Dam Full Supply Level (FSL) by 7 metres.
PIn order to begin the design, ISA carried out a stability analysis on the existing concrete gravitydam wall as well as the dam wall in its proposed raised state and found that methods to improve the wall stability prior to the dam raising needed to be incorporated.In this regard, the use of post-tensioned anchors were investigated and found to be the most cost effective solution for the dam wall in question. It was determined that once the dam wall stability was improved by way of the post-tensioned anchors, the FSL of the dam could be raised by way of constructing a Piano Key Weir (PKW) at the location of the existing spillway. A detailed investigation and model simulation determined that an uncontrolled spillway by means of a PKW was a viable solution from an engineering perspective as well as an economical one. ISA completed the design of the 100 metre long, 7 metre high PKW as well as the incorporation of 250 no. 3.4MN post-tensioned rock anchors in 2013. Through the DWS procurement system, a preferred contractor was identified and construction is scheduled to begin in April 2015 of the R500 million project.