Automatic design of basin-specific drought indexes for highly regulated water systems

Abstract

Abstract. Socio-economic costs of drought are progressively increasing worldwide due to undergoing alterations of hydro-meteorological regimes induced by climate change. Although drought management is largely studied in the literature, traditional drought indexes often fail in detecting critical events in highly regulated systems, where natural water availability is conditioned by the operations of water infrastructures such as dams, diversions, and pumping wells. Here, ad hoc index 5 formulations are usually adopted based on empirical combinations of several, supposed-to-be significant, hydro-meteorological variables. These customized formulations, however, while effective in the design basin, can hardly be generalized and transferred to different contexts. In this study, we contribute FRIDA (FRamework for Index-based Drought Analysis), a novel framework for the automatic design of basin-customized drought indexes. In contrast to ad-hoc, empirical approaches, 10FRIDA is fully-automated, generalizable, and portable across different basins. FRIDA builds an index representing a surrogate of the drought conditions of the basin, computed by combining all the relevant available information about the water circulating in the system identified by means of a feature extraction algorithm. We used the Wrapper for Quasi Equally Informative Subset Selection (W-QEISS), which features a multi-objective evolutionary algorithm to find Pareto-efficient subsets 15 of variables by maximizing the wrapper accuracy, minimizing the number of selected variables, and optimizing relevance and redundancy of the subset. The preferred variable subset is selected among the efficient solutions and used to formulate the final index according to alternative model structures. We apply FRIDA to the case study of the Jucar river basin (Spain), a drought prone, highly regulated Mediterranean water system, where an advanced drought management plan relying on the 20

Automatic design of basin-specific drought indexes for highly regulated water systems

“…A drought is a slowly developing natural phenomenon that occurs in all climatic zones and can be defined as a temporary significant decrease in water availability (Tallaksen and Van Lanen, 2004;Van Loon and Van Lanen, 2012). Drought impacts can propagate to virtually every water-related sector, such as farming and livestock production, industry, power generation, and public water supply (Spinoni et al, 2016).…”

“…Moreover, it can be further worsened by an inadequate design and management of the water exploitation system and its operating rules (Mishra and Singh, 2010). Operational drought indicators aim at comparing water availability to human water needs and serve as a measure of water well-being, rather than a measure of natural fluctuation as in the case of meteorological, agricultural, and hydrological indicators (Sullivan et al, 2003;Rijsberman, 2006). In the computation of operational drought indicators, the available water is often represented by the streamflow, or a fraction of it, and the water need is usually quantified by a standard per capita or by a fixed nominal demand (Falkenmark et al, 1989;Raskin et al, 1997).…”

Response to Reviewer #1

“…A drought is a slowly developing natural phenomenon that occurs in all climatic zones and can be defined as a temporary significant decrease in water availability (Tallaksen and Van Lanen, 2004;Van Loon and Van Lanen, 2012). Drought impacts can propagate to virtually every water-related sector, such as farming and livestock production, industry, power generation, and public water supply (Spinoni et al, 2016).…”

“…Moreover, it can be further worsened by an inadequate design and management of the water exploitation system and its operating rules (Mishra and Singh, 2010). Operational drought indicators aim at comparing water availability to human water needs and serve as a measure of water well-being, rather than a measure of natural fluctuation as in the case of meteorological, agricultural, and hydrological indicators (Sullivan et al, 2003;Rijsberman, 2006). In the computation of operational drought indicators, the available water is often represented by the streamflow, or a fraction of it, and the water need is usually quantified by a standard per capita or by a fixed nominal demand (Falkenmark et al, 1989;Raskin et al, 1997).…”