Determining urvban flood vulnerability using indicator based approach

Abstract

With increase in urbanisation and climate change, urban flood (UF) is becoming more frequent and intense – surpassing other types of flooding in terms of death and damage to critical infrastructure (CI) buildings. Guwahati, gateway to the eight states of north-east India, is prone to recurring UF – three to four times annually. The lack of an urban drainage network has added to the suffering of the residents. A major portion of the building stock are non-engineered and many new constructions are without UF compliance. Considering that the population and buildings are at risk, this research aims to develop a comprehensive UF vulnerability index (UFVI) as a combination of two indices – human vulnerability index (HVI) and building vulnerability index (BVI). Modified on various concepts of vulnerability assessment for hazards in the developing world, the UFVI has been proposed considering inherent hardships related exclusively to UF. For this purpose, in a prior survey conducted in the 31 municipal wards of the city, relevance of the HVI was checked by choosing residents as survey respondents and the BVI will be conducted based on the concept of rapid visual screening (RVS) of buildings. The HVI stratified the population into five tiers (‘very high’ to ‘very low’) and the BVI is expected to stratify the CIs similarly. These two indices will be combined in HAZUS-MH platform to obtain the UFVI ward-wise. This paper puts forward a theoretical explanation of the method that will be incorporated once the BVI is developed and while combining HVI and BVI to develop the UFVI. The composite UFVI that will be obtained will contribute to long-term actions for improving resilience of the existing population and CIs of the city against UF