Management of flood impacts and mitigation strategies: a case study of Purnia, Bihar

Abstract

Floods are probably the most recurring, widespread, disastrous, and frequent natural hazards of the world. These cause enormous damage to life, property, and disruption to infrastructure. Further, it badly affects agriculture, which is the mainstay of the economy in India. In India, Bihar is one of the worst affected states due to floods. It lies between West Bengal in the east and Uttar Pradesh in the west. It is limited by Nepal in the north and Jharkhand in the south. The Bihar plain is separated into two inconsistent parts by the waterway Ganga which courses through the center from west to east. The whole North Bihar is bungled by the significant streams, for example, the Ghaghra, the Gandak, the Bagmati, the Kamla-Balan, the Koshi, and the Mahananda which all, meet the mighty Ganga to its left side bank. As per one estimate, flood affects 76% population in the North Bihar living under the recurring threat of flood devastation. Bihar makes up 16.5% of India's flood-affected area and 22.1% of India's flood-affected population. 68,800 square kilometers (26,600 sq mi) out of 94,160 square kilometers (36,360 sq mi), is flood affected. In terms of long and recurrent flood hazards, the rivers in the northern Bihar plains of eastern India present a challenge. The river continues to carry a great deal of suffering by extensive flooding, despite a long history of flood control management in the basin for more than 5 decades. The problem of flooding in the river basin and provides a detailed study of flood hydrology. The hydrological research is combined with a GIS-based mapping of flood risk in parts of the basin. Typical river hydrological characteristics include very high variability of discharge and the high flux of sediment. Annual peak discharges often exceed the mean annual flood, and the low-lying tracts of the alluvial plains are extensively inundated year after year. Our flood risk analysis follows a multi-parametric approach using Analytical Hierarchy Process (AHP) and integrates geomorphological, land cover, topographic and social (population density). The flood risk map is validated with long-term inundation maps and offers a cost-effective solution for planning mitigation measures in flood-prone This study aims to analyze the impact of flooding and developing mitigation strategies that incorporate the prevention or reduction of flood damage. The objective is to understand the existing scenario of flooding; analyze the risks and extent of the impact of flood; and development of mitigation strategies for both social and economic impacts.