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Breach flow criteria:
This criterion corresponds to step criterion is adopted from step 5 of CUR Aanbeveling 113, 2008.
When considering the geometry of the slope, are there parts of the slope with a height as given in the first column of the tables below which is equal to or steeper than the slope given in the second column?
If so then the slope is breaching sensitive, so the check fails, so is sensitive to breaching. This means that the check fails and a Detailed check is neededshould be performed. In the case the slope height is over 40 is larger than 40 m a Detailed check is also needed.
Different cases are considered to determine the critical slope:
- a slope with or without flat bankshorizontal steps ("berms")
- the sand type:
- very fine sand with D50 ≤ 200 μm and D15 ≤ 100 μm
- medium fine sand with 200 < D50 ≤ 500 μm and 100 < D15 ≤ 250 μm
- coarse sand and gravel with D50 > 500 μm and D15 > 250 μm
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NOTE: In case the user-defined sand type is "very fine sand", the breach flow criteria can't cannot be checks checked and the program gives always that breach flow is possible and a warning message will be given in the Overall Results window.
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