South West Water
About the project
The 50m high concrete buttress dam in a National Park near Dulverton in Devon was constructed between 1974 and 1978. Since first impounding the reservoir there has been steadily rising flows recorded in the south abutment drainage system.
During the 2006 statutory inspection, it was concluded that in the interests of safety, further investigations should be undertaken into the location of the seepage and a study should be undertaken to identify appropriate measures to control the leakage and reduce it to acceptable levels.
In 2010 Ofwat approved expenditure for a major scheme to stabilise the south flank foundations under Wimbleball Dam during the AMP5 period (2010-2015). The work was jointly funded by South West Water and Wessex Water.
The works comprised the construction of a new grout curtain which was drilled from ground level within restricted spaces between buttress webs. Other works included drilling of new pressure relief wells from within the dam, earthworks to form a new access to the dam and installation of monitoring instrumentation.