Stabilizing Earthen Dams Built Over Timber Cribs

Construction of earthen dams created by burial of decaying rock-filled timber crib dams was one method used by our ancestors to quickly and inexpensively replace aging dams. Earthen dams require virtually no maintenance, whereas timber crib dams require constant upkeep to replace and repair decaying wood components. After burial, the timber components of the dam continue to decay, although at a greatly reduced rate. As these timber components decay, voids are created within the embankment. These voids can create water passages through the dam, leading to erosion and possible subsequent progressive breaching of the dam. This paper describes a project which was found to have a buried crib structure within the earth embankment, remedial options considered, project specific challenges and construction of the selected repair option.