The Role of Sensitivity Analysis in Selecting Dam Breach Parameters
Authors: Daniel Adria1, Violeta Martin1, Scott McDougall2
Conference: CDA 2023 Annual Conference
Date: October 22-25, 2023
1 Knight Piésold, Vancouver, British Columbia, Canada
2 University of British Columbia, Vancouver, British Columbia, Canada
ABSTRACT
This paper focuses on conducting sensitivity analysis to guide the selection of breach parameters for both water retaining and tailings dams. Sensitivity analysis on breach parameters could be undertaken using multiple empirical equations or through probability analysis (e.g., Monte Carlo simulations), which requires that a range and a statistical distribution are defined for each parameter. The governing considerations for breach parameter selection are discussed. These include, but are not limited to, dam construction type and construction materials, erosion or downcutting rates, topographic considerations, materials impounded behind the dam, and review of relevant historical cases. New empirical equations for eroded dam volume and dam erosion rate are presented that were developed using multiple linear regressions with breach height and breach outflow volume as inputs. An additional consideration specific to tailings dams is estimating the volume of tailings that could mobilize in a breach. This depends on the size of the supernatant pond, on tailings characteristics and their susceptibility to liquefaction, as well as on rheological characteristics that define their flowability, all of which impact the shape and the peak discharge of the breach outflow hydrograph.
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