Functional response evaluation of hard and soft adaptation strategies in urban flooding

Abstract

Intensified climate extremes in changing climate scenarios with rapid urbanization make urban floods a global concern since the population in the cities is increasing. One way to manage urban floods is the adoption of various adaptation measures. The existing infrastructures for flood adaptation are classified as 'hard,' 'soft,' and 'hybrid' adaptation strategies, which constitute the conventional Stormwater Drainage Network (SWD),  Green Infrastructures (GI) practices, and a combination of soft and hard strategies, respectively. As infrastructures are vulnerable to damage because of exceedance in design life, capacity, or any adverse situation, all adaptation methods are likely to become non-functional in the event of a disaster. Under such circumstances, the flood response of an urban region on account of the non-functionality of both soft and hard adaptation strategies is not well understood. We develop a coupled 1D-2D hydrodynamic model using MIKE+ and generate scenarios to compare the damages in the functional capacity of all three adaptation strategies. We implement this model for Ahmedabad city, India, and our Initial results show the hotspots which are highly prone to urban flooding. Here, we evaluate the hydrodynamic interaction between flood propagation on the surface with components of SWD structures and GI facilities and determine the consequence of their functional damages. Our analysis unfolds all the aspects of utilizing certain adaptation pathways, including the merits and demerits of the success and failure of a project. Our framework could aid in determining the trade-offs between different adaptation pathways from the perspective of building flood-resilient cities.