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The answer is "Yes" if D50 < 200 μm or D15 < 100 μm (only for sand and gravel soils) averaged over a thickness of 5 m between the water line and the toe of the channel slope.
NOTE: in the current version of the program, it is not checked if the thickness is minimal 5 m. The average is performed over a thickness of 5 m, by not taking into account the none-sandy layers.
Step 7: Is unstable breaching possible?
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