FAQ/ Appropriate location of riverside lines and breaches¶
In places where the embankment is wide (the embankment is thick), even if a breach occurred, it did not flow out into the floodplain. What could be the cause?
One possibility is that the ground height on the levee slope is used for the ground height of the flood model.
In DioVISTA, river and flood models are connected at the river line. Therefore, if the width of the levee is wider than the mesh size of the flood calculation, the flood model will also be defined on the levee slope. In this case, even if the levee breaks, the ground height of the floodplain maintains the original height of the levee, so even if a levee breaks, it will not flow out into the floodplain.
As a countermeasure, the following methods are possible.
Change the ground height on the levee slope to the same value as the ground height in the levee. This removes the effect of levee ground height from the flood model.
Move the riverbank line to the embankment instead of the top of the embankment. This means that the flood model is defined from the embankment law butt and not on the levee slope.