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FAQ/ How to prevent floodplains from flooding before breaches to calculate the risk zone of house collapse

In analyzing the house collapse risk zone (flooding), we would like to ensure that the floodplain (inland of the levee) is not flooded at the start of the breach. However, when analyzed by the usual method, overflow occurs upstream of the target levee point, so the floodplain is already inundated at the start of the break.

Even if overflow occurs from a river channel, is it possible to realize a situation where there is no water in the floodplain?


It is possible to make the area () an invalid area that does not affect the calculation of the overflow flow rate from the river channel and does not affect the flood flow from the break.[open]

Setting the elevation value for the calculation area to is a [open] negative infinity elevation for the specified mesh and the floodflow disappears.

However, in this setting, the flood flow from the breakdown point also disappears when it comes to the cell.

Therefore, if the floodplain cell connected to the river is set to , and the floodplain cell adjacent to the cell [open] is set to , the [close] overflow enters and [open] disappears, but the flood flow coming from the surrounding [open] area does not enter .

Last update: 2023-03-20