Stage-based flood inundation mapping

New methods allow the direct computation of flood inundation maps from lidar data, independently discharge estimates, hydraulic analysis, or defined cross sections. One method projects interpolated profile measured levels onto surrounding topography, creating a smooth surface that is entirely based on data and geometrical relationships. A second computes for any simple function relates water to elevation channel bottom, exploiting their known, sub-parallel character. final theoretically combines bottom upstream catchment area points along thalweg, all by data. Historical stream gauges can be incorporated generate floods having different return periods. The conceptual simplicity realism these facilitate data-based planning.