Delineation of Climate-Change Induced Flood Susceptible Zones: An Integrated Approach of Impact Assessment

Abstract

The occurrence of heavy rains caused by cyclones has emerged as a significant factor leading to the occurrence of floods in the state of Andhra Pradesh, located in South India. The current investigation utilized a combination of GIS and AHP techniques to determine the flood-prone zonation of nine administrative units situated along the Vamsadhara River in the Srikakulam district. The analysis incorporated 16 parameters to identify the Flood Susceptible Zone (FSZ) and involved sensitivity analysis of the variables employed to enhance the reliability of the findings. The FSZ maps obtained were divided into five categories: very high, high, moderate, low, and very low. From the results, it was determined that 19% of the entire study area fell into the very high FSZ classification, while 34% were classified as high FSZ. Additionally, 29% of the area fell into the moderate FSZ category, followed by 14% in the low category, and 4% in the very low category. Among the 9 mandals selected for study, a majority of over 50% of the land area in Gara, Lakshminarsupeta, Narasannapeta, Polaki, and Sarubujjili faced susceptibility that varies from very high to highly susceptible to inundations. Overlay analysis of the water area on the FSZ map before and after a Cyclone demonstrates that the waterlogged regions predominantly coincide with the high and very high susceptibility categories. The results presented in the paper will provide valuable assistance to state and local officials by offering profound insights to support the implementation of effective strategies to reduce future risks.