The Practical Use of Dam Foundation Drainage to Prevent Piping Failure in Small Farm Dams

Small farm dams are rarely constructed using optimal engineering practices due to cost and practical implementation constraints. In structures that are built of unstable or dispersible material the risk of failure is high. An engineering method of placing a drainage plane in the dam wall foundations so as to modify the flow net through a dam wall was trialled. The method was tested for effectiveness as a safety measure and its economic viability in small (< 20 ML) farm dams. The paper gives a brief overview of the standard methods used by the S.C.S. of New South Wales to control tunnel failure, details the test case, and evaluates the effects of applying the method on the structure over a three year period.