Pantnagar Journal of Research

Abstract

This paper describes the importance of flood mapping in terms of saving downstream agricultural land. Flood can cause high impact on the productivity of nearby crops which further affects the country's economy. The Baur dam is situated in Udham Singh Nagar district of Uttarakhand State of India. It has a Culturable Command Area of 65.72 km2 for Uttarakhand and 314.53 km2 for Uttar Pradesh state. Present study key focus is on describing the importance of Manning's roughness value in dam breach analysis. In this work hypothetical breach modelling of Baur dam is performed by using Hydrologic Engineer's Centre- River Analysis System (HEC-RAS 5.0.3) model. Details about study area, breach parameters, modelling procedure, and outflow flood values are also described. Flow hydrographs are plotted at different Manning's roughness value for the populated downstream areas of dam and it has been observed from the results that as roughness value increases, flow decreases which justifies Manning's theory. Inundation maps with varying Manning's values are plotted. The Manning's roughness value of 0.030 leads to 37.75 km2 inundated area in the downstream of dam.