Hello,
I want to set the inundation boundary in an area where the main stream’s riverbed is degenerated. The basin has an area of about 7 km2.
I have computed the flood hydrograph with the SCS method for a 12-hour precipitation. The data that are used are:
a) a 12-hour excess rainfall and
b) a 21-hour basin hydrograph.
I set the whole basin as a 2d flow area and calculated the floodplain lines using the above data.
With the excess rainfall the max floodplain spans most of the basin.
When i set the flow hydrograph at the upstream boundary, the floodplain lines are confined in a more reasonable distance in either side of the degenerated stream but the water depth is significantly higher.
What would be the most realistic flood boundary for this case?
Thank you
Paul