Wadi Qattarah Dams Case History

Two earthfill dams were constructed on the Wadi Qattarah in Libya between 1969 and 1972 but the filling was never ach1eved for both dams. After a partial filling well below normal water level, Secondary Dam failed in December 1977. Several weaknesses may be found in the features of both dams and have been analyzed by the authors on the basis of dam instrumentation results, measurements and observations of the Secondary Dam failure. Several possible causes of failure of this dam are presented. No one can however be taken as certain. The series of events as reported by eye witnesses appear to point out a typical phenomenon of piping, but the responsible mechanism can be attributed to var1ous causes