Dam break flood wave analysis and the floodplain mapping using mathematical models A case study, Vanyar Dam

In the current research, the dam breach and break problem have been presented from
the view points of importance of the problem, mechanism, spatial and temporal
analysis as well as governing mathematical equations.
For this purpose, the output hydrographs from the Vanyar dam site have been
computed by breach model under two fictitious dam break scenarios (i.e. overtopping
and piping) as the first step.
In the next step, the output hydrographs have been routed through the downstream
river by using HEC-RAS model. Then water levels and velocities have been computed
at all cross sections.
Finally the obtained results have been imposed to GIS in order to obtain visible
presentation of the results to develop floodplain maps. Considering the obtained
results, the output hydrographs will have moderated shape but will not have very
instantaneous flash condition, because gradually breach mechanism may be occurred
in the dam in both scenarios. Further more, the most power of the flood will be
decreased without any significant financial problems under the geomorphological and
topographical conditions in near part of the river close to dam.
However, the study shows that some villages and manufactories in the downstream
may be prone with some mirror damages. Also the maximum flood and its arrival time
at the down stream have been calculated.