River basins may have gauged and ungauged catchments. To determine flow contributions from the catchments distributed parameter modeling is required. Geographic Information System (GIS) can handle spatially varied parameters efficiently and is useful in developing IUH/UH for watersheds. Multiple inflows routing model can integrate a number of upstream flows to compute the common downstream flow rate on the basis of several upstream flows. This book describes flood flow modeling for river systems having a number of gauged and ungauged watersheds. Flow contribution from the ungauged watersheds...