McDowall Affleck was engaged by the Shire of Mundaring to complete an inspection of the Lake Leschenaultia dam wall upper face rock work which was being undermined by wave action. The issues we needed to address were the protection of the upstream embankment and provision of subsoil drainage to the downstream embankment.
We provided a design brief to complete the remedial action as well as construction methodology. This included an estimate of construction costs as well as providing detail of the remedial works to the Shire of Mundaring in order to obtain a grant from the Lotteries Commission.
The answer was therefore to design and have constructed a keyway alongside the upstream dam embankment approximately 300mm wide, 700mm into the natural ground and 300mm out of the ground at low water level made from concrete and rock. The area between the keyway and the base of the embankment could then be filled with concrete and some rock to stabilise the base of the embankment, and to make it look like the existing rock and concrete pitching. The provision of the keyway would stop the embankment from being undermined due to wave action and sliding of the embankment due to the undermining of the rock.
The project was successful and Lake Leschenaultia continues to be a popular and iconic destination for families in the area.