Socioeconomic drought under climate change and population growth

Abstract:

Drought is a complex natural hazard that may have destructive damages on societal properties and even lives. Generally, socioeconomic drought occurs when water resources systems cannot meet water demand mainly due to a weather-related shortfall in water supply. This study firstly proposes a new index, the socioeconomic drought index (SEDI), for identifying and evaluating socioeconomic drought events on different severity levels (i.e., slight, moderate, severe and extreme). Moreover, even if a socioeconomic drought ends, the antecedent water deficit may continue to have impacts for some time, thus influencing the resilience of a regional water resources system. To take this into account, especially under growing population and changing climate, this study then develops a new method through integrating a new index, Water Resources System Resilience Index (WRSRI), into socioeconomic drought event identification. The new index represents the percentage of the antecedent water deficit for a socioeconomic drought that can be recovered from the excess water during subsequent periods through analyzing records of a historical drought event. The methodology, implemented on the East River Basin (ERB) in South China, involves three major steps: (1) calculation of WRSRI value; (2) analysis of key features of identified future socioeconomic drought events, i.e., total number (TN), longest duration (LD), and percentage on different drought levels (PDDL)); and (3) sensitivity analysis of WRSRI based on a total of 52 streamflow datasets generated from General Circulation Model (GCM) outputs and using a macro-scale hydrologic model. The results indicate that, for each dataset, the TN decreases with an increase in WRSRI but the LD increases; for most datasets, the LD is less sensitive within the WRSRI range of [0, 0.6]. The outcomes of this study can enhance our capability in more effectively assessing the resilience of a regional water resources system, especially under changing future socioeconomic and environmental conditions.