Dam breach inundation study

Challenge

SLR conducted a dam breach analysis and inundation assessment for the water and historical tailings retention dam of a mine operation. A water reservoir located immediately downstream of this dam was included in the study to evaluate cascade dam failure. The reservoir is 3 km upstream of a city with a population of 160,000 people. The study was required by the client to develop flood mapping in support of emergency response planning.

Solution

The objectives of the study were to determine the potential tailings runout, the areal extent of the flooding impact in the event of dam failure, the peak flood water levels resulting from dam failure, and the flood wave travel times to various points of interest.

Impact

SLR’s project team identified credible failure modes and reasonable scenarios for hydrological and 2‑D hydraulic numerical modelling under dry and wet weather conditions. A phased approach was implemented to discuss results of the analyses at key milestones for decision making purposes prior to further advancing the study.

Given our expertise in this field, SLR is currently working on a separate project providing independent auditing for the development of robust analysis and audit standards for dam breach studies. As part of this work, SLR has been undertaking a review of current practices to establish solids runout estimates from potential dam failures.