2017 – Breach Development Relationships for Small Earthen Dams

Elaine Pang, Robert Fowden

There are numerous established methods available for assessing the consequences of failure for earthen water dams.The estimation of breach dimensions and failure times remains the greatest common area of uncertainty, particularly for dams under 10m in height, where the number of historic records behind the established methods reduces considerably.Also, various factors can have a significant impact on the strength of small dam embankments, potentially contributing to the likelihood of failure.Consequently, failure impact assessments for smaller dams may rely more heavily on the engineering judgement of the responsible engineer. Although the consequences of failure may indeed be lower for smaller dams, the large number of unknown or unregulated dams in some locations means that it can be difficult to quantify their overall contribution in terms of dam safety risk. This paper presents an on-going project to compile and analyse observed small earthen dam failures with the intent of refining existing statistical breach relationships for smaller dams.Context is provided through an overview of DEWS’ investigative program, including the presentation of several case studies which highlight field data collected throughout the program.