Using the Willowstick Method to Target Remediation and Prevent Dam Failure

Abstract Only - Magnetometric resistivity, also known as MMR, has been applied to over 160 dams all over the world including: Australia, Austria, Canada, China, Norway, South Africa, South Korea, Sri Lanka, Sweden, United Kingdom, and United States. MMR is used to identify preferential seepage flow paths through, under, or around dams. If seepage flow paths are not repaired, they can cause erosion, sink holes, and eventually dam failure. Some of the consequences of failure are: loss of life, environmental damage, and social license to operate. Finding the preferential seepage flow paths is an expensive and slow process, often characterized by drilling “trial and error” boreholes that further impair the integrity of the structure. A better alternative is to identify the exact location and depth of the seepage path(s) and then repair the dam where needed. Geophysical technologies, applied to the study area in question, along with 3D models are a cost effective and accurate way to identify the seepage flow paths. In this paper, results of a MMR investigation from Laurel Bed Dam (Virginia, USA), Bartley Dam (UK), and Durlassboden Dam (Austria) are presented. All of the dams in this paper used the MMR method to identify the exact location and depth of preferential seepage flow path(s). The results of each of these investigations have been confirmed and the necessary repairs have been performed.