Levee Erosion Prediction Equations Calibrated with Laboratory Testing

Shewbridge, Scott E.; Perri, J. F.; Mineart, Philip; Millet, Richard; Huang, Wilbur; Vargas, Juan; Inamine, Mike; Mahnke, Steve

doi:10.1061/41147(392)28

Cited by 1 publication

(3 citation statements)

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“…The critical shear stress of the materials forming the dam (t c ) and the erodibility coefficient (k) can be taken as 4 psf (0.2 kPa) and 0.01 ft 3 /lb-h (0.0006 m 3 /kg-h), respectively. These correspond to very resistant material (Shewbridge et al 2010), which is consistent with the Revelstoke earthfill dam characteristics. The hydraulic stress was estimated as:…”

Section: Probability Of a Dam Breachsupporting

confidence: 80%

“…Therefore, the study considers the probability of a breach of the concrete gravity dam to be negligible given a failure of the Checkerboard Creek rock slope and this section focuses on the earthfill dam. While models to analyze dam breach caused by wind-generated waves have been developed (Wang and Bowles 2006;Shewbridge et al 2010), there are no fully developed models focused on earthfill dam robustness against overtopping by a single large wave. Balmforth et al (2008) suggested some moraine dam failures could be attributed to dam breaching following overtopping by large waves; they tested dam physical models of granular material under large waves and presented a theoretical model to rationalize their observed results.…”

Section: Probability Of a Dam Breachmentioning

confidence: 99%

“…A simple method that relates erosion rate to hydraulic and geotechnical parameters (Shewbridge et al 2010) was adopted:…”

Section: Probability Of a Dam Breachmentioning

confidence: 99%

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Development and application of a quantitative risk assessment to a very slow moving rock slope and potential sudden acceleration

et al. 2015

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Development and application of a quantitative risk assessment to a very slow moving rock slope and potential sudden acceleration Abstract The benefits of quantitative risk assessments for landslide management have been discussed and illustrated in several publications. However, there still are some challenges in its application for low-probability, high-magnitude events. These challenges are associated with the difficulties in populating our models for risk calculations, which largely require the input of expert opinion. This paper presents a quantitative risk assessment to a very slow moving rock slope within a dam reservoir in the Province of British Columbia, Canada. The assessment is focused on the risk to the population in the vicinity of the dam and the populated areas downstream. Expert opinions quantified the slope failure probabilities in the order of 10 −3 to 10 −1 per year for the smallest failure scenario considered and less than 10 −6 for a failure of the entire slope. However, these estimations are associated with high levels of uncertainty. Our approach starts with the calculation and assessment of the magnitude and probability of the potential slope failure consequences, minimizing the uncertainties associated with estimated slope failure probabilities. Then, these consequences and failure probabilities are combined to obtain a measure of risk. The uncertainty associated with the slope failure probabilities is managed by the estimation of plausible ranges for these. The calculated risk levels are then presented as ranges of values and assessed against adopted evaluation criteria. The consequence and risk assessment of the rock slope suggest that the risk to the population exposed in the vicinity of the dam and populated areas downstream is under adequate control. The probability of large consequence scenarios is extremely low, in the order of 10 −7 chance of an event causing more than 100 fatalities. We propose an observational technique to assess changes in risk levels and decide when to update the risk management approach or deploy emergency measures. The technique is focused on the detection of changes in the slope deformation patterns that would indicate an increase in the potential failure volumes or an imminent failure. It can be considered an extension to the current early warning system in place, easy to implement and enhanced with the strength of the comprehensive analysis required for a quantitative risk assessment.Keywords Risk assessment . Landslide hazard . Rock slope . Consequence analysis Checkerboard Creek rock slope The Revelstoke Dam, part of a hydroelectric generation project on the Columbia River, has an installed capacity of 2,480 MW. A future expansion is being planned that would increase the capacity by another 500 MW (BC Hydro 2014). The dam, 5 km upstream of Revelstoke, British Columbia, comprises a 1,160-m-long earthfill dam that wraps around a 183-m-long concrete gravity dam and the concrete gravity spillway structure (Taylor and Lou 1983;Salmon 1988). Figure 2 shows the...

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Section: Probability Of a Dam Breachsupporting

confidence: 80%

Section: Probability Of a Dam Breachmentioning

confidence: 99%