The construction of a US$25M seepage control blanket at the Cleveland dam in Canada is due to start in March 2001. The potential for seepage and instability of the east abutment of the dam was first recognised in 1954 when the concrete dam was built. The western abutment is set in rock, but on the eastern side the buried rock valley is infilled with silt, sand, gravel and glacial till. It is hoped that the seepage control project will make the dam safer.