EFFECT OF LAND USE ON FLOOD DISASTER: A CASE STUDY OF HINDON RIVER

Abstract

Floods are among the most devastating natural hazards in the world, leading to more economic and social damages than any other natural phenomena. Flood is dependent on both hydrologic as well as hydraulic parameters. River flow is governed by hydrologic parameters like discharge and hydraulic parameters like velocity, boundary shear stress and water surface profile. Due to increase in population and consequent decrease in per capita resources, the population of rural area often migrates towards city. The population of city areas is increasing while the settlement area remains constant, and it disturbs the existing land use pattern. A number of people start residing on flood plains leading to flood plain encroachment or changing the land use according to their desires/needs. Since the change in land use pattern for urban settlement or vegetation or industrialization affects the hydraulic behavior of river, it is imperative to understand the sensitivity of land use changes on hydraulic parameters. The land use changes affect the surface roughness which, in turn, affects velocity and consequently the depth of flow for a given discharge. The present study has dealt with the sensitivity analysis of roughness coefficient in terms of Manning’s n on inundation and finally on flooding. The lower region of Hindon River has been taken as present study area. Hindon is a tributary of River Yamuna. It originates from lower Himalayas in Saharanpur district of Uttar Pradesh State and flows to a length of about 400 km and passes through six districts namely Muzaffarnagar, Meerut, Baghpat, Ghaziabad and Gautambudh Nagar until its confluences with River Yamuna. This study presents change in hydraulic parameters like water surface profile due to change in land use, i.e. the change in land use will cause change in Manning’s roughness coefficient, n. Land use map is prepared from landsat-8 imagery by using ERDAS Imagine software. Surveyed data is then incorporated in ASTER DEM and modified in Arc GIS. The Manning’s roughness coefficient used for present study is obtained by taking into account the pattern of land use. There are four sets of Manning’s n (= 0.035, 0.0543, 0.0613 and 0.076) value used in the study obtained by combining different land uses. The objective of this study is to compare the results thus obtained with different time steps and different cell sizes. Flood inundation map is prepared with unique discharge to quantify the change in inundation by change in land use. The results of this study are found to be consistent with the usual expectations.