Unsteady Flow Computation for Planning Flood Control Projects

Abstract

One of the most important information for planning flood control projects is the design flood level which is generally determined either on the basis of observations or by calculating the steady water surface profile. The flood levels are, however , rarely associated with steady flow since at the time of flood peak the water level is also affected by the variation of discharge. When flood control measures — like the design of flood dikes, diversions, reservoirs etc. — are under consideration their effect on flood level should be predicted , otherwise proper sizes /e. g. elevation of dyke crests/ can not be determined with satisfactory accuracy. The effect of alluvial rivers may also affect the design flood levels, and the prediction of these changes is a very important part of the design procedure.