Schlumberger Water Services is a leader in the application of hydrodynamic models for river engineering and flood hazard mapping. We have experience in unsteady-flow simulation for modeling the propagation of a flood wave through river and floodplain systems, and expertise in applications of two-dimensional models for analyzing changes in velocity fields around structures. Our services include: water surface profile analysis for complete flood hydrographs and multiple channels; simulation of tidal effects; impacts of reservoir spillway gate operation over a complete time series; and modeling of wind set-up and dam breach analysis for determining the extent of potential downstream inundation. We couple hydrodynamic models with GIS applications for flood hazard mapping and preparing floodplain management plans. MIKE 11 and HEC RAS are modeling packages commonly used by Schlumberger Water Services.