Urban Flood Vulnerability, Economic Loss, Functionality Loss, and Restoration Modeling in Built Environment: Probabilistic Model Formulation and Application in a Mixed Formal and Informal Setting

Flooding is well recognized as one of the most destructive natural disasters, often leading to heavy losses of lives, property, and economy. Flood impacts are often presented in terms of flood vulnerability/fragility functions considering univariate intensity measures. However, flooding duration also plays an instrumental role in physical damage, functionality loss, and economic losses. This prompts the development of multivariate flood vulnerability and loss models; however, such models are not available in the existing literature to the best of our knowledge. To address this gap, we develop multivariate and univariate flood vulnerability models, economic loss models, and restoration models for Reinforced Concrete (RC), masonry, steel, and semi-permanent buildings. Similar models are also developed for agricultural land using actual damage/loss data. Bivariate models considering inundation depth and inundation duration are developed using response surface method, whereas several univariate vulnerability and loss models are also presented. The models are interpreted together with the outcomes of two-dimensional flood hazard analysis to outline and exemplify probabilistic flooding scenarios and likely consequences. The sum of observations highlights that although physical damage can be limited in building structures, considerable functionality and economic losses will be inevitable due to urban flooding.