Making the distinction between water scarcity and drought using an observation‐modeling framework

Abstract

[1] Drought and water scarcity are keywords for river basin management in water-stressed regions. ''Drought'' is a natural hazard, caused by large-scale climatic variability, and cannot be prevented by local water management. ''Water scarcity'' refers to the long-term unsustainable use of water resources, which water managers can influence. Making the distinction between drought and water scarcity is not trivial, because they often occur simultaneously. In this paper, we propose an observation-modeling framework to separate natural (drought) and human (water scarcity) effects on the hydrological system. The basis of the framework is simulation of the situation that would have occurred without human influence, the ''naturalized'' situation, using a hydrological model. The resulting time series of naturalized state variables and fluxes are then compared to observed time series. As second, more important and novel step, anomalies (i.e., deviations from a threshold) are determined from both time series and compared. We demonstrate the use of the proposed observation-modeling framework in the Upper-Guadiana catchment in Spain. Application of the framework to the period 1980-2000 shows that the impact of groundwater abstraction on the hydrological system was, on average, four times as high as the impact of drought. Water scarcity resulted in disappearance of the winter high-flow period, even in relatively wet years, and a nonlinear response of groundwater. The proposed observation-modeling framework helps water managers in water-stressed regions to quantify the relative impact of drought and water scarcity on a transient basis and, consequently, to make decisions regarding adaptation to drought and combating water scarcity.Citation: Van Loon, A. F., and H. A. J. Van Lanen (2013), Making the distinction between water scarcity and drought using an observation-modeling framework, Water Resour.

The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and the Cabauw polder

“…To investigate if the model can also be used for water management scenario analyses or to separate natural and human effects on the hydrological system (see Van Loon and van Lanen, 2013, and references therein), we simulated the change in the hydrological variables as a result of water management operations in the Cabauw polder. As mentioned in Sect.…”

Ensemble projections of future streamflow droughts in Europe

“…Anthropogenic drivers, such as intensive water use and poor water management, can further exacerbate low-flow conditions in watersheds, with a consequent increase in vulnerability to drought (e.g., Vörösmarty et al, 2000;Tallaksen and van Lanen 2004;Döll et al, 2009;Wada et al, 2013a). Water scarcity reflects the imbalance that arises from an overexploitation of water resources, caused by consumption being significantly higher than the natural renewable availability (Schmidt and Benítez-Sanz, 2013;Van Loon and Van Lanen, 2013). Albeit water scarcity may relate to any hydrological condition, it is more likely to occur under drought conditions due to reduced water availability.…”

Assessment of Groundwater Drought in the Mangyeong River Basin, Korea

“…The hydrograph was continually at the bottom of the 95% occurrence line from August 2008 to February 2009; in 2015, the GWL decreased to below the 95% occurrence line many times (Figure 10e). natural situation [30,58]. Seasonal groundwater droughts appeared at well G-2 every year until 2011 but since 2012 the overall GWL increased and the lowest GWL settled near the average GWL (Figure 9b).…”

“…It is likely that the use of groundwater increased due to the decrease in both reservoir storage and surface water during the drought period. If anthropogenic factors influence the lack of water, drought can be aggravated with respect to the natural situation [30,58].…”