Calculate maximum flooded area based on maximum flood levels along a stream

Discussion created by scolarphips on Mar 12, 2013
Latest reply on May 14, 2015 by say_ali

I need to assess the extent of a maximum flood along a river, based on maximum flood levels along this river.

However, there is a lack of availability and reliability of hydrological data for this stream, so that an out-of-the-box approach must be sufficient.

My approach is assessing the traces of past maximum flood levels (e.g. by level of garbage in bush and trees or coloured water line along concrete walls along the river bed) and taking their maximum level of elevation and their coordinates. I could basically interpolate these locations to get a denser representation of the maximum flood level along this stream.

However, does anyone knows if it is possible to expand the point information along the river into space through a polygon, based on my DEM, to get the inundation area?

Looking forward for your ideas!