Development of flood depth-damage functions for Kampala

Abstract

Floods are the most common and destructive form of natural disasters around the world. Floods are going to be magnified and intensified by future climate change, rapid urbanisation, and urban drainage asset deterioration and thus this research is providing a way to quantify flood effects that result so that mitigation measures can be set up. The areas affected by floods are at a greater risk of losing infrastructure and human lives and pose a threat to prospering economies. Because of this, the economic loss that results from such extreme events needs to be quantified to mitigate them or be more prepared to know the resulting damage that will occur. This is useful to policymakers and those in authority. Flood depth-damage functions are used for damage assessments after a flood has occurred. This research developed flood depth-damage functions for Kampala using Kinawataka catchment. This involved field surveys in the flood-affected villages within the catchment. Following the surveys, the data was analysed and using a Coupled 1D-2D model of the catchment, damage functions of damage versus depth, damage versus velocity and damage versus depth and velocity were developed. The function with both velocity and depth entailed the use of a parameter that combines depth and velocity values into one representative value. With these functions, improved flood risk maps can be created; annual expected damage can also be obtained and this will help in flood risk assessment and urban planning.