Identification of urban waterlogging risk zones using Analytical Hierarchy Process (AHP): a case of Agartala city

Abstract

Urban waterlogging has become a critical environmental issue of global significance, frequently causing extensive property damage and human casualties. In Agartala city, severe waterlogging problems arise from rapid urban development, disruption of natural drainage systems, intense rainfall, population growth, and poorly planned drainage infrastructure. With the use of the Analytical Hierarchy Process (AHP) technique, this study attempts to model and identify the hazards, vulnerabilities, and waterlogging risks in Agartala. Waterlogging is particularly prevalent during the monsoon season, when heavy rainfall inundates low-lying areas, leading to significant disruptions. To produce a waterlogging inventory map for the city of Agartala, the primary investigation was carried out. The study employs an integrated approach combining geographic information system (GIS) and remote sensing (RS) techniques, considering 16 parameters to develop hazard and vulnerability maps. The results reveal that approximately 3.45% of Agartala, covering 2.64 sq/km, is in the very high-risk waterlogging zone, while 5.50% (4.21 sq/km) is in the high-risk zone. An additional 18.87% (14.44/km) falls into the moderate-risk category. The remaining areas are classified as low-risk, comprising 36.06 sq/km (47.12%), and very low-risk zones, covering 19.17 sq/km (25.06%). High-risk zones are primarily located in the city’s central part, where low-lying terrain and dense urbanization create conditions conducive to waterlogging. There is a good correlation between the detected waterlogging-prone locations and ground truth data, as evidenced by the receiver operating characteristic (ROC) curve, which produced an area under the curve (AUC) value of 0.801 or 80.1%. This study introduces an innovative approach to assessing waterlogging risk zones, applied for the first time in Agartala city. By developing a comprehensive waterlogging inventory map, the research offers a detailed analysis of spatial variations in waterlogging risk. The study’s findings will assist decision-makers in developing medium- to long-term mitigation strategies to reduce waterlogging-related hazards and guide proper future land-use planning. This research shows that the integrated AHP approach is effective in identifying waterlogging risk zones in Agartala and can support planning and mitigation efforts to prevent future waterlogging incidents globally.

Graphical Abstract