I am assessing the flood risk posed by pipeline failure. I need to calculate the likely flow-paths for flood water downstream of critical locations along the pipeline using GIS.
I'm familiar with ArcGIS and QGIS/GRASS/SAGA methods for calculating channel networks and catchments upstream from a point but what would be the best method for assessing downstream flow-paths originating at a point location?
Ideally any method would be fairly automated as a number of locations are being assessed.
I have ArcGIS 9.3 and QGIS (latest version) available to me.