Water-Related Hazard and Risk Management

Water-related hazard events are extreme hydrological phenomena that cause loss of lives, injuries, damage to properties, socio-economic and environmental impacts. Damage can be reduced by using control and mitigation measures that can be classified as structural and non-structural measures. This chapter introduces several, even seldom considered hazards. Floods being swift and devasting events receive a special attention. Flood flow computation can be carried out by using hydrological and hydrodynamic models for flood prediction and flood forecasting, etc. Return periods of floods can be determined by probability analysis of extreme events such as maximum streamflow data from past records. The return periods are used as a bench mark in determining the extent of floods for planning and design purposes. Different levels of hazard are considered in estimating the risk level for planning and design of mitigation measures. Vulnerability of population and their assets depends on types of land use, their socio-economic values, exposure and environment. Damage due to extreme events depends on hazard magnitude and types of objects such as population, their assets and infrastructures threatened by these hazards. Risk maps can be drawn to show spatial variation of risk under different magnitudes of hazard and vulnerability. Risk control and adaptation as well as risk sharing are given ample emphasis in this chapter.