Future Drought Events Research Articles

Drought Risk under Climate and Land Use Changes: Implication to Water Resource Availability at Catchment Scale

Although the climate change projections are produced by global models, studying the impact of climatic change on water resources is commonly investigated at catchment scale where the measurements are taken, and water management decisions are made. For this study, the Frome catchment in the UK was investigated as an example of midland England. The DiCaSM model was applied using the UKCP09 future climate change scenarios. The climate projections indicate that the greatest decrease in groundwater recharge and streamflow was projected under high emission scenarios in the 2080s. Under the medium and high emission scenarios, model results revealed that the frequency and severity of drought events would be the highest. The drought indices, the Reconnaissance Drought Index, RDI, Soil Moisture Deficit, SMD and Wetness Index, WI, predicted an increase in the severity of future drought events under the high emission scenarios. Increasing broadleaf forest area would decrease streamflow and groundwater recharge. Urban expansion could increase surface runoff. Decreasing winter barley and grass and increasing oil seed rape, would increase SMD and slightly decrease river flow. Findings of this study are helpful in the planning and management of the water resources considering the impact of climate and land use changes on variability in the availability of surface and groundwater resources.

Induced water stress affects seed germination response and root anatomy in Robinia pseudoacacia (Fabaceae)

The different germination behaviours of the seeds under induced water limitations may be related to the different adaptive capacities acquired at the diverse collection sites, as a response to the different environmental parameters. The island of Pianosa resulted the most performant in term of germination responses and the co-occurrence of xeromorphic anatomical evidences at root level confirmed this trend. Regeneration from seeds is an important co-determinant in the invasion ecology of black locust. In the attempt of providing new information on its invasion potential in Mediterranean Europe under the future scenario of global warming, we investigated the effects of induced water-deficit regimes on: (1) seed germination performance and (2) root growth and anatomy. Ripe seeds were collected from four populations established in Tuscany (Central Italy): mechanically scarified seeds were incubated in a range (− 0.2/− 0.8 MPa) of constant water stress conditions at 21 °C. The final germination rate drastically declined with increasing induced water-deficit conditions, with the highest value at control and at − 0.2 MPa (ca 50–97%), and the lowest at − 0.6 MPa (ca 10–33%). The mean germination time decreased with increasing water stress. At root level, xeromorphism relies on the combination of different anatomical traits which co-optimize water uptake/loss: thinner roots, higher number of xylem vessels, vessels with small-sized lumen and thinner cell walls. Seeds collected in sites characterized by different environmental parameters display a noteworthy difference in the germination dynamics: as far as the beginning and ongoing of germination, as well as the germination response in time is concerned, the seeds from the island of Pianosa showed the highest performance; the major arid conditions in Pianosa could have caused a “stress imprint” able to facilitate a fast and protective response to future drought events. As a whole, our results confirmed the great phenotypic plasticity of black locust as a response to variable water availability and provided evidence for the potential high germination capacity in drier environments, as seems to be the future Mediterranean Europe.

Copula‐Based Convection‐Permitting Projections of Future Changes in Multivariate Drought Characteristics

AbstractProbabilistic projections of future drought characteristics play a crucial role in climate change adaptation and disaster risk reduction. This study presents a copula‐based probabilistic framework for projecting future changes in multivariable drought characteristics through convection‐permitting Weather Research and Forecasting simulations with 4‐km horizontal grid spacing. A probabilistic multivariate drought index is introduced to examine the joint effects of drought indicators with uncertainty intervals for four major river basins located in South Central Texas of the United States. Markov chain Monte Carlo is used to address uncertainties in assessing copula parameters and in predicting climate‐induced changes in hydrological regimes. Our findings reveal that the severity and intensity of drought episodes can be amplified when considering the compound effects of soil moisture and runoff regimes by using the probabilistic multivariate drought index. The South Central Texas region is projected to experience more drought events with shorter duration and higher intensity in a changing climate. The drought severity will not necessarily increase due to the decreasing drought duration. In addition, our findings indicate that the intensity of future droughts is expected to increase as a result of the deficiency of soil moisture even though precipitation extremes are projected to become more frequent. Moreover, climate change impacts on multivariate drought characteristics will intensify with the increasing temporal scales (i.e., short‐, medium‐, and long‐term droughts) although the number of future drought events may decrease by the end of this century.

Water-Use Characteristics and Physiological Response of Moso Bamboo to Flash Droughts.

Frequent flash droughts can rapidly lead to water shortage, which affects the stability of ecosystems. This study determines the water-use characteristics and physiological mechanisms underlying Moso bamboo response to flash-drought events, and estimates changes to water budgets caused by extreme drought. We analyzed the variability in forest canopy transpiration versus precipitation from 2011–2013. Evapotranspiration reached 730 mm during flash drought years. When the vapor pressure deficit > 2 kPa and evapotranspiration > 4.27 mm·day−1, evapotranspiration was mainly controlled through stomatal opening and closing to reduce water loss. However, water exchange mainly occurred in the upper 0–50 cm of the soil. When soil volumetric water content of 50 cm was lower than 0.17 m3·m−3, physiological dehydration occurred in Moso bamboo to reduce transpiration by defoliation, which leads to water-use efficiency decrease. When mean stand density was <3500 trees·ha−1, the bamboo forest can safely survive the flash drought. Therefore, we recommend thinning Moso bamboo as a management strategy to reduce transpiration in response to future extreme drought events. Additionally, the response function of soil volumetric water content should be used to better simulate evapotranspiration, especially when soil water is limited.

Effect of climate change on the centennial drought over China using high-resolution NASA-NEX downscaled climate ensemble data

The impacts of climate change on future drought properties in various regions across China are accessed using multiple statistical approaches, based on 20 downscaled global climate models provided by NASA (NEX-GDDP) under Representative Concentration Pathways (RCP) 4.5 and RCP8.5 emission scenarios. Results show that temperature plays a crucial role on the variability of drought conditions in China by comparing the discrepancies between Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). Unobvious variability of drought extent is projected for SPI, while the drought extent for SPEI is remarkable. Based on SPEI, a considerable aggravation in spatial extent and severity of future drought events are found in the majority of regions, particularly in northwest and northeast China, except for winter over northeast region. The drought extent increases more significantly after late 2070s under RCP8.5 scenario, and the differences of drought extent are not significant between RCP4.5 and RCP8.5 scenarios in the early and mid-twenty-first century. More than 85% of the regions show a decreasing trend for SPEI in spring, summer, and autumn, suggesting drought tendency in most of China, and drought frequency also increases significantly in north and northwest China except for winter. The dramatic aggravation of drought attribution is mainly projected to the increases in potential evapotranspiration (PET) in northwestern and northern regions of China, whereas in northwestern region, the exacerbating drought conditions are expected to the attribution of deficiencies of rainfall. At national scale, PET plays a more dominant role to the future severe and widespread droughts across China in the context of climate change.

Structural memory in grapevines: Early season water availability affects late season drought stress severity

Abstract In the future drought events are expected to occur more frequently, with unpredictable rain and heat events. In current research we investigated how different water availability patterns influenced late season plant water status in Vitis vinifera. ‘Cabernet Sauvignon’ grapevines were grown for three consecutive years. We compared the response to five water availability regimes: High, Intermediate, Low (along all season) and High-to-Low (High during the beginning of vegetative seasons switched to low during the rest of season) and Low-to-High (opposite treatment). Midday stem water potential (SWP) was measured weekly to determine the seasonal pattern of drought stress. Xylem anatomy was investigated by trunk vessel diameter measurements, and specific axial xylem conductivity was calculated according to Hagen-Poiseuille's law. Vines exposed to high water availability treatment showed improved seasonal water status along the season, compared to vines in the low treatment. Vines exposed to High-to-Low water regime showed a markedly improved water status at the beginning of the season, but became the most severely stressed toward the end of season. The SWP values were more negative in the High-to-Low regime even when compared to the Low water regime. Water availability at the beginning of the season (during main period of cambial activity) determined the vessel characteristics: high water availability during cambial activity increased vessel diameter and thus specific hydraulic conductivity. Our data strongly indicates that regulated drought stress can be induced by manipulating xylem structural parameters via controlling water availability during the period of stem cambial activity.

Socioecological Determinants of Drought Impacts and Coping Strategies for Ranching Operations in the Great Plains

In Great Plains rangelands, drought is a recurring disturbance. Ranchers in this region expect to encounter drought but may not be adequately prepared for it. Efforts to encourage drought preparedness would benefit from a better understanding of the conditions under which managers make decisions to minimize the impacts of drought. We tested the direct and moderating roles of the drought hazard and the social-ecological context on drought impacts and response. This study was conducted with ranchers in western and central South Dakota and Nebraska following the drought that began in 2012. We surveyed ranchers regarding the effects of the drought and their responses and used multimodel analysis to explore the relationships among measures of drought preparedness, drought response, and drought impacts. Drought severity was the primary predictor of all impacts, but specific types of impacts were varied depending on the operation’s enterprise mix, resources, and management. The socioecological characteristics of the ranch system predicted drought response actions taken, by either providing the necessary resources and capacity to take action or creating sensitivity in the system that required action to be taken. We conclude with recommendations for learning from current drought experiences in order to better adapt to future drought events.

The limits of resilience in US community responses to recent drought events

ABSTRACT Drought threatens many facets of community life, including food security, agricultural and tourism livelihoods, recreation, esthetic appeal, and social cohesion. Many policy responses to a drought crisis are enacted at the municipal level, including voluntary water conservation, burn bans, outdoor watering restrictions, municipal water source expansion, and drought contingency plans. Though communities have many reasons to limit their vulnerability to future drought events, it is questionable whether these measures do. In a comprehensive survey of more than 450 news media reports on drought response in communities across the United States, this study defines 27 common response approaches. Results show that responses tend to be short-term emergency coping measures. Temporary water restrictions may not leave communities prepared to address future water crises. Furthermore, restrictions can create tension amongst levels of governance. Recommendations based in resilience theory suggest that collaboration, engagement, and forward-looking planning processes are necessary to address community drought vulnerability.

Reliability–Resiliency–Vulnerability Approach for Drought Analysis in South Korea Using 28 GCMs

This study developed a Reliability–Resiliency–Vulnerability (R–R–V) approach that aggregates the frequency, duration, and severity of droughts estimated using the Standardized Precipitation Evapotranspiration Index (SPEI). This approach was used to analyze the characteristics of droughts for the current (1976–2005) and the future (2010–2099) climates. The future climate data obtained from 28 general circulation models (GCMs) of Coupled Model Intercomparison Project Phase 5 (CMIP5) was divided into three general periods: Future 1: 2010–2039, Future 2: 2040–2069; and Future 3: 2070–2099. As a result, aggregation R–R–V representing water availability would increase during Future 1, and then gradually decrease until the end of the century. The frequencies of future drought events for Future 2 and Future 3 were similar to the current frequency, while the durations will be longer and the severity will be higher at most locations during Future 3. Thus, the mean of R–R–V over South Korea is expected to decrease, except for Future 1, and the spatial variability of R–R–V is expected to increase. In the end, the changes in the mean and variance of rainfall and temperature would lead to a decrease in the mean and increase in the spatial variation of sustainability in South Korea. This approach and its results can be used to establish a long-term drought strategy for regions where the risk of future drought is expected to increase.

Autotrophic and heterotrophic soil respiration responds asymmetrically to drought in a subtropical forest in the Southeast China

Both increasing frequency of drought and drought duration are expected for many terrestrial ecosystems under on-going climate change. However, our understanding of the drought effect on soil respiration (Rs), which comprises the second largest carbon (C) flux of the global C cycle, remains limited. To explore the effects of reduced precipitation on Rs and its components, we conducted an experiment of throughfall rainfall exclusion during two consecutive growing seasons in a subtropical forest in the Southeast China. Following throughfall exclusion Rs declined rapidly, and did not recover until three to four months following rewetting, in both 2014 and 2015. During the experiment, throughfall exclusion significantly reduced autotrophic soil respiration (Ra); however, heterotrophic soil respiration (Rh) was unaffected, resulting in a reduced contribution (Ra/Rs) from 33 ± 1% for the control to 16 ± 3% under throughfall exclusion. Experimental drought significantly reduced soil microbial C and fine root biomass, and subsequent to rewetting, soil microbial C recovered quickly, but fine root biomass relapsed slowly. Our results suggested that prolonged drought decreases Rs through modifications in soil microbial activities and fine root metabolic capacity, which are induced by reduced soil water availability. Moreover, our results imply that drought-induced reductions in Rs originate primarily from Ra. Our results highlight the need to account for asymmetric responses to drought between Ra and Rh when predicting the reaction of the ecosystem C balance in response to future drought events.

Encroachment Dynamics of Juniperus virginiana L. and Mesic Hardwood Species into Cross Timbers Forests of North-Central Oklahoma, USA

Cross Timbers forests, typically dominated by Quercus stellata Wangenh. and Q. marilandica Muenchh., are the transition zone between eastern deciduous forest and prairie in the southern Great Plains. Fire exclusion beginning in the mid-1900s has led to increasing stand density and encroachment of fire-intolerant Juniperus virginiana L. and mesic hardwood. We measured current forest structure and tree ages of 25 stands (130 plots) in north-central Oklahoma to characterize the extent and dynamics of encroachment. The respective basal area and stand density of the overstory (diameter at breast height; dbh &gt; 10 cm) were 19.0 m2 ha−1 and 407 trees ha−1 with Q. stellata comprising 43% of basal area and 42% of stand density. Quercus marilandica represented only 3% of basal area and 4% of overstory density. Juniperus virginiana represented 7% of basal area and 14% of stand density while mesic hardwoods, e.g., Celtis spp., Ulmus spp., Carya spp., 33% of basal area and stand density. The sapling layer was dominated by mesic hardwoods (68%) and J. virginiana (25%) while the seedling layer was dominated by mesic hardwoods (74%). The majority of Quercus recruited into the overstory between 1910–1970, while recruitment of J. virginiana and mesic hardwoods began more recently (post 1950s). Growth rate, based on the relationship between age and dbh, was faster for mesic hardwoods than for J. virginiana and Q. stellata. These results indicate that removal of recurrent surface fire as a disturbance agent has significantly altered forest composition in the Cross Timbers region by allowing encroachment of J. virginiana and fire-intolerant, mesic hardwoods. This increases wildfire risk because J. virginiana is very flammable and will alter how these forests respond to future drought and other disturbance events.

Drought Stress and Root-Associated Bacterial Communities.

Root-associated bacterial communities play a vital role in maintaining health of the plant host. These communities exist in complex relationships, where composition and abundance of community members is dependent on a number of factors such as local soil chemistry, plant genotype and phenotype, and perturbations in the surrounding abiotic environment. One common perturbation, drought, has been shown to have drastic effects on bacterial communities, yet little is understood about the underlying causes behind observed shifts in microbial abundance. As drought may affect root bacterial communities both directly by modulating moisture availability, as well as indirectly by altering soil chemistry and plant phenotypes, we provide a synthesis of observed trends in recent studies and discuss possible directions for future research that we hope will provide for more knowledgeable predictions about community responses to future drought events.

Climate change enhances the severity and variability of drought in the Pearl River Basin in South China in the 21st century

Drought is expected to increase in frequency, severity, and duration in the future due to global warming and this will greatly threaten the future socio-economic development. This study evaluates the spatiotemporal variation of future drought (2016–2100) in the Pearl River Basin (PRB) using the Palmer drought severity index (PDSI), the Variable Infiltration Capacity (VIC) model, and future climate projections based on the general circulation models (GCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) under three representative concentration pathway (RCP) scenarios. The results show that future drought conditions are expected to be more serious than historical (1960–2015) drought conditions in the PRB, especially under RCP8.5. The severity and variability of future drought conditions are also higher than for the historical period. The west Guangxi and South Guizhou provinces exhibit the highest increment in drought severity under the three RCP scenarios. At the seasonal scale, drought severity shows the highest increment in the winter with little change in summer; the summer drought severity increases in most areas of the PRB but the increment of the drought severity is lower than the winter. The number of future drought events is expected to decrease but the duration and severity are expected to increase, especially in the mid-west PRB and under high greenhouse gas (GHG) emission scenarios. In summary, in most areas of the PRB, the severity and variability of drought are expected to increase in the 21st century, especially in the mid-west PRB and an increase in evapotranspiration is assumed to be the main underlying cause. Irrigation projects and agricultural production in the PRB might face serious threats of drought in the future.

Exploring the utility of drought indicators to assess climate risks to agricultural productivity in a humid climate

AbstractDrought indices have been extensively used by the hydrological research community for understanding drought risks to water resources systems. In a humid climate, such as in England, most agricultural production is rainfed and dependent on summer rainfall, but knowledge of drought risks in terms of their occurrence and potential agronomic impacts on crop productivity remains limited. This paper evaluated the utility of integrating data from three well-established drought indices, including the standardised precipitation index (SPI), the standardised precipitation evapotranspiration index (SPEI) and the Palmer drought severity index (PDSI), with simulated yield outputs from a biophysical crop model for potato, a drought-sensitive and high-value crop. The relationships between drought onset and yield response were statistically evaluated. The SPEI-3 drought indicator was found to be most suited to monitoring water availability and hence drought conditions for both rainfed and irrigated production. ‘Heat maps’ were produced to illustrate the strength of the correlation between the modelled SUBSTOR-Potato yields and SPEI for different aggregation periods and monthly lags. Finally, the outputs were used to assess alternative ways in which decision-making could be improved regarding adaptation strategies to reduce agricultural system vulnerability to future drought events.

Projected Changes of Future Extreme Drought Events under Numerous Drought Indices in the Heilongjiang Province of China

Effective drought prediction methods are essential for the mitigation of adverse effects of severe drought events. This study utilizes the Reconnaissance Drought Index, Standardized Precipitation Index and Standardized Precipitation Evapotranspiration Index to assess the occurrence of future drought events in the study area of the Heilongjiang province of China over a period of 2016–2099. The drought indices were computed from the meteorological data (temperature, precipitation) generated by the global climate model (HadCM3A2). Moreover, Mann-Kendall trend test was applied for the assessment of future climatic trends and detecting probable differences in the behaviour of various drought indices. Drought forecasting periods has been divided into three categories: the early phase (1916–2030), middle phase (2031–2060) and late phase (2061–2099). The occurrence of future droughts is also ranked according to their intensity (mild, moderate, severe and extreme drought). Based on the drought results, more number of drought events are expected to occur during 12-month drought analysis are, RDI during 2084–2098 (DD = 14, DS = −1.38), SPEI during 2084–2098 (DD = 14, DS = −1.33) and SPI during 2084–2095 (DD = 12, DS = −1.19). The 1st and 2nd months of the years studied predicted a warming trend, while the 7th, 8th, and 9th months predicted a wetter trend. Finally, it was observed that RDI is more sensitive to drought and indicated a high percentage of years under severe and extreme drought conditions during the drought frequency analysis. Conclusively, this study provides a strategies for water resources management and monitoring of droughts, in which drought indices like RDI can play a central role.

Analysis of future drought characteristics in China using the regional climate model CCLM

In this paper, the intensity, area and duration of future droughts in China are analyzed using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). The SPI and SPEI are used to evaluate the simulation ability of drought characteristics with the regional climate model COSMO-CLM (CCLM). The projected intensity and duration of future drought events are analyzed for the period 2016–2050 under three different respective concentration pathways (RCPs). The simulated and projected drought events are analyzed by applying the intensity-area-duration method. The results show that CCLM has a robust capability to simulate the average drought characteristics, while some regional disparities are not well captured, mainly the simulation of more drought events of shorter duration in Northwest China. For the future period 2016–2050, more intense dryness conditions are projected for China. An increase in evapotranspiration is found all over China, while a reduction in precipitation is apparent in the southern river basins. The increase in evapotranspiration plays an important role in the changes of future droughts over the northern river basins and southern river basins. Under RCP2.6, drought events of longer duration and with higher frequency are projected for the southwest and southeast of China. Under RCP4.5 and RCP8.5, a continuing tendency to more dry conditions is projected along a dryness band stretching from the southwest to the northeast of China. More frequent drought events of longer duration are projected in the southwestern river basins. For all future droughts, larger extents are projected, especially for events with long-term duration. The projected long-term drought events will occur more often and more severe than during the baseline period, and their central locations will likely shift towards Southeast China. The results of this study can be used to initiate and strengthen drought adaptation measures at regional and local scale, especially in the south of China.

Changes in the natural dynamics of Nothofagus dombeyi forests: population modeling with increasing drought frequencies

AbstractDrought‐induced episodes of tree mortality can determine forest dynamics and structure, particularly in forests dominated by single species. Short‐ and mid‐term climate projections indicate that strong changes in annual precipitation may strike more often in northern Patagonia. Data for recruitment, growth, and survival of Nothofagus dombeyi tree individuals were collected at several sites across the Nahuel Huapi National Park in Argentina. We combined mathematically all these different demographic stages into an Integral Projection Model to simulate 100‐yr projections of simulated stand structure under different frequencies of extreme drought episodes. We projected total basal area and the number of individuals for three different initial stand types (i.e., young, medium, and old) and for varying drought frequencies (i.e., from 1 to 5 drought events every 100 years). Recruitment into the dbh ≥ 10 cm size class under normal conditions (i.e., without drought) was higher than under episodic drought conditions. In addition, survival under normal conditions was higher than under drought conditions, especially for small trees. Differences in growth were also important, with trees growing more vigorously under normal than under drought conditions. Our simulations predicted that N. dombeyi populations would experience a reduction in tree density in the mid‐term if, as predicted by the IPCC projections, the frequency of future drought events increased. The simulations also showed that in those cases, young stands should suffer the most. Drought‐mediated changes may induce a decline in the development of N. dombeyi forests in the mid‐ and long term by a drastic reduction in tree density.

Drought forecasting using ANFIS- a case study in drought prone area of Vietnam

Drought occurs throughout the world, affecting people more than any other major natural hazards. An important requirement for mitigating the impact of drought is an effective method of forecasting future drought events. This study investigated the applicability of Adaptive neuro-fuzzy inference system (ANFIS) for drought forecasting and quantitative value of drought indices, the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). Khanhhoa Province Vietnam with three meteorological stations was selected as the study area. The sea surface temperature anomalies (SSTA) events at NinoW and Nino4 zones were selected as input variables to forecast drought. Fifteen ANFIS forecasting models for SPI/SPEI (1, 3, 6, and 12 months) were trained and tested. The results show the performance of the ANFIS forecasting models for SPI/SPEI of all stations is equivalent and most ANFIS forecasting models for SPEI are better than SPI; the performance of the ANFIS forecasting models for SPI/SPEI-12 is better than other ANFIS models for SPI/SPEI-1 to SPI/SPEI-6; the models with high performance are M10–M13; model with the highest performance is M12 model. The results of this research showed that ANFIS forecasting models with SSTAs events as input variables can forecast longer term than SPI and precipitation as input variables. The ANFIS forecasting model with SSTA events as input variables can be successfully applied and provide high accuracy and reliability for drought forecasting.

Developing drought resilience in irrigated agriculture in the face of increasing water scarcity

In many countries, drought is the natural hazard that causes the greatest agronomic impacts. After recurrent droughts, farmers typically learn from experience and implement changes in management to reduce their future drought risks and impacts. This paper aims to understand how irrigated agriculture in a humid climate has been affected by past droughts and how different actors have adapted their activities and strategies over time to increase their resilience. After examining recent drought episodes from an agroclimatic perspective, information from an online survey was combined with evidence from semi-structured interviews with farmers to assess: drought risk perceptions, impacts of past drought events, management strategies at different scales (regional to farm level) and responses to future risks. Interviews with the water regulatory agency were also conducted to explore their attitudes and decision-making processes during drought events. The results highlight how agricultural drought management strategies evolve over time, including how specific aspects have helped to reduce future drought risks. The importance of adopting a vertically integrated drought management approach in the farming sector coupled with a better understanding of past drought impacts and management options is shown to be crucial for improving decision-making during future drought events.

Assessment of 21st century drought conditions at Shasta Dam based on dynamically projected water supply conditions by a regional climate model coupled with a physically-based hydrology model.

Along with socioeconomic developments, and population increase, natural disasters around the world have recently increased the awareness of harmful impacts they cause. Among natural disasters, drought is of great interest to scientists due to the extraordinary diversity of their severity and duration. Motivated by the development of a potential approach to investigate future possible droughts in a probabilistic framework based on climate change projections, a methodology to consider thirteen future climate projections based on four emission scenarios to characterize droughts is presented. The proposed approach uses a regional climate model coupled with a physically-based hydrology model (Watershed Environmental Hydrology Hydro-Climate Model; WEHY-HCM) to generate thirteen equally likely future water supply projections. The water supply projections were compared to the current water demand for the detection of drought events and estimation of drought properties. The procedure was applied to Shasta Dam watershed to analyze drought conditions at the watershed outlet, Shasta Dam. The results suggest an increasing water scarcity at Shasta Dam with more severe and longer future drought events in some future scenarios. An important advantage of the proposed approach to the probabilistic analysis of future droughts is that it provides the drought properties of the 100-year and 200-year return periods without resorting to any extrapolation of the frequency curve.