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A flow slide can occur if one of the two following conditions is met:
- The Liquefaction is possible: the total slope (channel edge-channel bottom) is on average steeper than or equal to 1 : [7 × (HR/24)(1/3) ], in which HR is defined below.
- Breaching is possible (: see paragraph below called "Breaching Breach flow criteria")
If the criteria of occurrence is met, the Global check FAILS and it should be switched to the Detailed method.
If the criteria of occurrence is not met, the Global and the Overall checks SUCCEED.
Liquefaction flow criteria:
HR [m] is the height of the submerged slope in its most unfavourable situation during the assessment period and determined with:
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- cotaR is equal to cotaonder.
- H [m] is the height of the submerged slope (
)
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Breach flow criteria:
This criterion is adopted from step 5 of CUR Aanbeveling 113, 2008.
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- the calculated diameter D50;5m if a Detailed check is performed
- the calculated diameter D15;5m and D5;5m is an Advanced Breach flow check is performed
In case of a incoherence, the Overall result gives a Warning message.
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(a) In D-Flow Slide, the ground surface level (GL) (maaiveld in Dutch) is the lowest level between the water level and the top of the channel slope (called "Insert river channel").
Table A.4.2b from CUR113b, profile with flat berms:
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from depth
[m +GL(a)]
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)
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0
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Z1
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10
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.
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15
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1:3
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20
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1:3.5
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25
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1:4
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30
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1:4.67
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35
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1:5.43
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40
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