Tony Wahl. 2016. "Estimating Breach Outflow Characteristics for Reclamation Canals". Bureau of Reclamation, Report Number HL-2016-01.

Abstract: Methods are developed and presented for making preliminary estimates of the peak breach outflow and maximum DV value (product of flow depth and velocity) that could occur during floods resulting from the unintended breaching of canal embankments. Charts and equations are presented that allow flood characteristics to be estimated as a function of the normal canal flow rate, the operating Froude number, the ratio of average width to flow depth, and a soil erodibility parameter that can be measured using in situ or laboratory testing methods, or can be estimated from basic soil properties and knowledge of original compaction conditions. Insights gained during development and initial application of the methods to a range of Reclamation canals are discussed. Canal conveyance capacity and the relatively small volume of water stored in a canal (compared to a typical water storage reservoir) can significantly limit the magnitude of canal failure floods. The study found--somewhat independent of canal size--that when the soil detachment rate parameter (kd) is less than 0.5 ft/hr/psf, canal embankments are likely to fail slowly enough that catastrophic flood releases are improbable due to the chance for successful intervention by canal operators to stop, delay, or otherwise mitigate the failure process.


Web Link: ../pubs/HL/HL-2016-01.pdf

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