FAQ/ Specification of backflow from the breach¶
When flow from the floodplain back to the river channel occurs through the breach, is the flow rate taking into account the levee height or the levee height?
response¶
Yes, that's how it is.
However, depending on [Broken Levee] the properties [Use the ground height of the floodplain (reverse flow permit)] , it behaves differently.
A value of this [True] allows you to return from the floodplain to the river channel. In addition to the breach point, the river channel also returns to the point where the water level of the floodplain exceeds the top of the embankment. However, if there is a virtual wall in that leg, the virtual wall setting takes precedence.
If this value [False] is , it will not return from the floodplain to the river channel. The default value is [False] . [False] In the case of, floodplain water never returns to the river. However, if there is a drainage station, it will return to the river through it. And if there are oceans, sewage, open cells, etc., then through them the water disappears.
For more information, please refer to FAQ/Building a wall on a river and FAQ/Even if you erect a wall on a river, you want to return it to the floodplain.