HYDROLOGICAL STUDY FOR ESTIMATION OF DESIGN FLOOD OF BETWA BASIN UP TO RAJGHAT DAM SITE

Abstract

In planning water resources development projects the knowledge of the peak and magnitude of the flood that have to be adopted in the design of engineering structures is of great importance. If the design flood adopted is low, it may cause overtopping or even failure of the structure when a higher flood than this occurs. As such it will damage life and built up property located in the downstream. On the other hand if the design flood adopted is too high, it will unnecessarily increase the cost of the structure and even economic feasibility of the project may not be possible. Therefore selection of design flood is based on optimal com-bination of risk, safety and economy. There are various methods available in the literature for estimation of the design flood, when no rainfall or run off data for any basin is available. The flood may be estimated by empirical formulae or enveloping curves. A suitable factor of safety can also be applied to maximum recorded flood to estimate the design flood. Storm studies and application of unit hydrograph gives the complete design flood hydrograph. The method based on statistical approach ( flood frequency analysis) has the capacity to determine the risk involved in adopting a particular value of design flood.. Hydrologic model considers the temporal and spatial variations of rainfall and it is a better metaod.