Hydrological Drought: Water Surface and Duration Curve Indices

Hydrological drought is defined as significant reduction in all forms of water availability within the land phase of the hydrological cycle (e.g., surface water, snowmelt, spring flow, and groundwater). Hydrological drought occurs due to a lack of precipitation over a prolonged period resulting in lakes, reservoirs, and rivers drying up and groundwater being depleted. In this chapter, the authors discuss the basic concepts of drought, the classification of drought, and the various types of water loss due to drought. The main focus is on hydrological drought, that is, the drought related to surface water storage, whose various characteristics and indices will be explained. The chapter also includes a case study of an analysis of hydrological drought using the L-moments method on the Satluj River in Himachal Pradesh, India.