Usage of Rockfill Dams in the HEC-RAS Software for the Purpose of Controlling Floods

摘要

Employment of delayed Rockfill dams without impermeable membrane is an appropriate tool for controlling flood. For this purpose first hydraulic currents should be discerned from the Rockfill dams so that we can obtain the stage discharge relation for them. Secondly the unsteady currents in the open channels should be fully analyzed. This can be performed through solving the Saint-Venant equations. Since solving such equations, especially for a network of open channels with various cross sections is very complex and time-consuming, appropriate software should be used. N this research the HEC-RAS has been employed. Results obtained for the discharge-gauge relation of Rockfill dam is used in this software. Data required for employing this software include: blueprint of the network of channels, mapping results of various network sections, roughness coefficient of various network, distances between the mapped sections, and hydrograph of a definite flood, location and specifications of Rockfill dam or dams. Output of this software includes: water level profile and the inflow hydrographs at various points of the network and hydrograph of the outflow flood the Rockfill dam.