Discussion “A probability distibution for hydrological drought duration”

2021 ◽  
pp. 127032
Author(s):  
Zekâi Şen
Keyword(s):  
Hydrological Drought ◽  
Drought Duration

scholarly journals Hydrological Drought Regimes of the Huai River Basin, China: Probabilistic Behavior, Causes and Implications

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2390 ◽  
Author(s):  
Sun ◽  
Zhang ◽  
Yao ◽  
Wen
Keyword(s):  
River Basin ◽  
Hydrological Drought ◽  
Drought Severity ◽  
Copula Functions ◽  
Drought Duration ◽  
Huai River Basin ◽  
Huai River ◽  
The Impact ◽  
Hydrological Droughts ◽  
The Huai River Basin

: Hydrological droughts were characterized using the run-length theory and the AIC (Akaike information criterion) techniques were accepted to evaluate the modeling performance of nine probability functions. In addition, the copula functions were used to describe joint probability behaviors of drought duration and drought severity for the major tributaries of the Huai River Basin (HRB) which is located in the transitional zone between humid and semi-humid climates. The results indicated that: (1) the frequency of hydrological droughts in the upper HRB is higher than that in the central HRB, while the duration of the hydrological drought is in reverse spatial pattern. The drought frequency across the Shiguan River along the south bank of the HRB is higher than the other two tributaries; (2) generalized Pareto distribution is the appropriate distribution function with the best performance in modelling the drought duration over the HRB; while the Generalized Extreme Value (GEV) distribution can effectively describe the probabilistic properties of the drought severity. Joe copula and Tawn copula functions are the best choices and were used in this study. Given return periods of droughts of <30 years, the droughts in the upper HRB are the longest, and the shortest are in the central HRB; (3) the frequency of droughts along the mainstream of the HRB is higher than tributaries of the HRB. However, concurrence probability of droughts along the mainstream of the HRB is lower than the tributaries of the HRB. The drought resistance capacity of HRB has been significantly improved, effectively reducing the impact of hydrological drought on crops after 2010.

scholarly journals Quantifying human impacts on hydrological drought using a combined modelling approach in a tropical river basin in central Vietnam

2018 ◽  
Vol 22 (1) ◽  
pp. 547-565 ◽  
Author(s):  
A. B. M. Firoz ◽  
Alexandra Nauditt ◽  
Manfred Fink ◽  
Lars Ribbe
Keyword(s):  
River Basin ◽  
Reservoir Operation ◽  
Human Impacts ◽  
Hydrological Drought ◽  
Drought Risk ◽  
Climatic Data ◽  
Strong Impact ◽  
Hydropower Development ◽  
Drought Duration ◽  
Central Vietnam

Abstract. Hydrological droughts are one of the most damaging disasters in terms of economic loss in central Vietnam and other regions of South-east Asia, severely affecting agricultural production and drinking water supply. Their increasing frequency and severity can be attributed to extended dry spells and increasing water abstractions for e.g. irrigation and hydropower development to meet the demand of dynamic socioeconomic development. Based on hydro-climatic data for the period from 1980 to 2013 and reservoir operation data, the impacts of recent hydropower development and other alterations of the hydrological network on downstream streamflow and drought risk were assessed for a mesoscale basin of steep topography in central Vietnam, the Vu Gia Thu Bon (VGTB) River basin. The Just Another Modelling System (JAMS)/J2000 was calibrated for the VGTB River basin to simulate reservoir inflow and the naturalized discharge time series for the downstream gauging stations. The HEC-ResSim reservoir operation model simulated reservoir outflow from eight major hydropower stations as well as the reconstructed streamflow for the main river branches Vu Gia and Thu Bon. Drought duration, severity, and frequency were analysed for different timescales for the naturalized and reconstructed streamflow by applying the daily varying threshold method. Efficiency statistics for both models show good results. A strong impact of reservoir operation on downstream discharge at the daily, monthly, seasonal, and annual scales was detected for four discharge stations relevant for downstream water allocation. We found a stronger hydrological drought risk for the Vu Gia river supplying water to the city of Da Nang and large irrigation systems especially in the dry season. We conclude that the calibrated model set-up provides a valuable tool to quantify the different origins of drought to support cross-sectorial water management and planning in a suitable way to be transferred to similar river basins.

scholarly journals Future discharge drought across climate regions around the world modelled with a synthetic hydrological modelling approach forced by three General Circulation Models

2013 ◽  
Vol 1 (6) ◽  
pp. 7701-7738 ◽  
Author(s):  
N. Wanders ◽  
H. A. J. van Lanen
Keyword(s):  
General Circulation ◽  
Reference Model ◽  
Control Period ◽  
General Circulation Models ◽  
Hydrological Drought ◽  
Severe Drought ◽  
Drought Duration ◽  
Increased Risk ◽  
The World ◽  
Drought Occurrence

Abstract. Hydrological droughts characteristics (drought in groundwater and streamflow) likely will change in the 21st century as a results of climate change. Magnitude and directionality of these changes and their dependency on climatology and catchment characteristics, however, is largely unknown. In this study a conceptual hydrological model was forced by downscaled and bias-corrected outcome from three General Circulation Models for the A2 emission scenario (GCM forced models), and the WATCH Forcing Data re-analysis dataset(reference model). The threshold level method was applied to investigate drought occurrence, duration and deficit volume. Results for the control period (1971–2000) show that the drought characteristics of each GCM forced model reasonably agree with the reference model for most of the climate types, suggesting that the climate model's results after post-processing produce realistic outcome for global drought analyses. For the near future (2021–2050) and far future (2071–2100) the GCM forced models show a decrease in drought occurrence for all major climates around the world and increase of both average drought duration and deficit volume of the remaining drought events. The largest decrease in hydrological drought occurrence is expected in cold (D-)climates where global warming results in a decreased length of the snow season and an increased precipitation. In the dry B-climates the smallest decrease in drought occurrence is expected to occur, which probably will lead to even more severe water scarcity. However, in the extreme climate regions (desert and polar), the analysis for the control period showed that projections are in these regions most uncertain. On a global scale the increase in hydrological drought duration and severity will lead to a higher impact of drought events, which urges water resources managers to timely anticipate on the increased risk on more severe drought in groundwater and streamflow and to design pro-active measures.

scholarly journals Hydrological Drought Characteristics Based on Groundwater and Runoff Across Europe

2020 ◽  
Vol 383 ◽  
pp. 281-290
Author(s):  
Samuel Jonson Sutanto ◽  
Henny A. J. Van Lanen
Keyword(s):  
Hydrological Model ◽  
Meteorological Drought ◽  
Hydrological Drought ◽  
Weather Data ◽  
Model Resolution ◽  
Southeast Europe ◽  
Annual Average ◽  
Drought Duration ◽  
Drought Characteristics ◽  
Groundwater Drought

Abstract. Hydrological drought often gets less attention compared to meteorological drought. For water resources managers, information on hydrological drought characteristics is prerequisite for adequate drought planning and management. Therefore, the aim of this study is to analyse hydrological drought characteristics in the pan-European region based on past drought events from 1990 to 2017. The annual average drought duration, deficit volume, onset, termination, and intensity during drought years were calculated using daily runoff and groundwater data. All data were simulated with the LISFLOOD hydrological model (resolution 5×5 km) fed with gridded time series of observed weather data. Results based on runoff and groundwater data show that regions in Northeast to Southeast Europe, which stretched out from Poland to Bulgaria, were identified as profound regions to severe hydrological drought hazards. The most severe droughts during our study period were observed in 1992 to 1997, where on average Europe experienced drought events, which lasted up to 4 months. Long average drought durations up to 4 and 8 months in runoff and groundwater occurred in a few parts of the European regions (around 10 % area). Longer drought durations and a lower number of drought events were found in groundwater drought than in runoff, which proved that slow responding variables (groundwater) are better in showing extreme drought compared to fast responding variables (runoff). Based on our results, the water managers can better prepare for upcoming drought and foster drought adaptation actions.

scholarly journals Hydrological drought across the world: impact of climate and physical catchment structure

2013 ◽  
Vol 17 (5) ◽  
pp. 1715-1732 ◽  
Author(s):  
H. A. J. Van Lanen ◽  
N. Wanders ◽  
L. M. Tallaksen ◽  
A. F. Van Loon
Keyword(s):  
Large Scale ◽  
Hydrological Drought ◽  
Temperate Climate ◽  
Minor Effect ◽  
Hydrological Models ◽  
Drought Duration ◽  
Groundwater System ◽  
Drought Characteristics ◽  
The World ◽  
Groundwater Systems

Abstract. Large-scale hydrological drought studies have demonstrated spatial and temporal patterns in observed trends, and considerable difference exists among global hydrological models in their ability to reproduce these patterns. In this study a controlled modeling experiment has been set up to systematically explore the role of climate and physical catchment structure (soils and groundwater systems) to better understand underlying drought-generating mechanisms. Daily climate data (1958–2001) of 1495 grid cells across the world were selected that represent Köppen–Geiger major climate types. These data were fed into a conceptual hydrological model. Nine realizations of physical catchment structure were defined for each grid cell, i.e., three soils with different soil moisture supply capacity and three groundwater systems (quickly, intermediately and slowly responding). Hydrological drought characteristics (number, duration and standardized deficit volume) were identified from time series of daily discharge. Summary statistics showed that the equatorial and temperate climate types (A- and C-climates) had about twice as many drought events as the arid and polar types (B- and E-climates), and the durations of more extreme droughts were about half the length. Selected soils under permanent grassland were found to have a minor effect on hydrological drought characteristics, whereas groundwater systems had major impact. Groundwater systems strongly controlled the hydrological drought characteristics of all climate types, but particularly those of the wetter A-, C- and D-climates because of higher recharge. The median number of droughts for quickly responding groundwater systems was about three times higher than for slowly responding systems. Groundwater systems substantially affected the duration, particularly of the more extreme drought events. Bivariate probability distributions of drought duration and standardized deficit for combinations of Köppen–Geiger climate, soil and groundwater system showed that the responsiveness of the groundwater system is as important as climate for hydrological drought development. This urges for an improvement of subsurface modules in global hydrological models to be more useful for water resources assessments. A foreseen higher spatial resolution in large-scale models would enable a better hydrogeological parameterization and thus inclusion of lateral flow.

scholarly journals A generic method for hydrological drought identification across different climate regions

2012 ◽  
Vol 16 (8) ◽  
pp. 2437-2451 ◽  
Author(s):  
M. H. J. van Huijgevoort ◽  
P. Hazenberg ◽  
H. A. J. van Lanen ◽  
R. Uijlenhoet
Keyword(s):  
Land Surface ◽  
Threshold Level ◽  
Global Scale ◽  
Hydrological Drought ◽  
Dry Period ◽  
Drought Duration ◽  
Variable Threshold ◽  
The World ◽  
Level Method ◽  
Zero Runoff

Abstract. The identification of hydrological drought at global scale has received considerable attention during the last decade. However, climate-induced variation in runoff across the world makes such analyses rather complicated. This especially holds for the drier regions of the world (both cold and warm), where, for a considerable period of time, zero runoff can be observed. In the current paper, we present a method that enables to identify drought at global scale across climate regimes in a consistent manner. The method combines the characteristics of the classical variable threshold level method that is best applicable in regions with non-zero runoff most of the time, and the consecutive dry days (period) method that is better suited for areas where zero runoff occurs. The newly presented method allows a drought in periods with runoff to continue in the following period without runoff. The method is demonstrated by identifying droughts from discharge observations of four rivers situated within different climate regimes, as well as from simulated runoff data at global scale obtained from an ensemble of five different land surface models. The identified drought events obtained by the new approach are compared to those resulting from application of the variable threshold level method or the consecutive dry period method separately. Results show that, in general, for drier regions, the threshold level method overestimates drought duration, because zero runoff periods are included in a drought, according to the definition used within this method. The consecutive dry period method underestimates drought occurrence, since it cannot identify droughts for periods with runoff. The developed method especially shows its relevance in transitional areas, because, in wetter regions, results are identical to the classical threshold level method. By combining both methods, the new method is able to identify single drought events that occur during positive and zero runoff periods, leading to a more realistic global drought characterization, especially within drier environments.

scholarly journals Identification of the Space-Time Variability of Hydrological Drought in the Arid Region of Northwestern China

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1051 ◽  
Author(s):  
Huaijun Wang ◽  
Zhongsheng Chen ◽  
Yaning Chen ◽  
Yingping Pan ◽  
Ru Feng
Keyword(s):  
Arid Region ◽  
Water Resource Management ◽  
Space Time ◽  
Hydrological Drought ◽  
Northwestern China ◽  
Logistic Distribution ◽  
Time Variability ◽  
Drought Duration ◽  
Monthly Streamflow ◽  
Drought Duration And Severity

Drought monitoring is crucial to water resource management and strategic planning. Thus, the objective of this study is to identify the space-time variability of hydrological drought across the broad arid region of northwestern China. Seven distributions were applied to fitting monthly streamflow records of 16 gauging stations from 10 rivers. Finally, the general logistic distribution was selected as the most appropriate one to compute the Standardized Streamflow Index (SSI). The severity and duration of hydrological droughts were also captured from the SSI series. Moreover, we investigate the relationship between hydrological drought (SSI) and meteorological drought (Standardized Precipitation-Evapotranspiration Index (SPEI)) at different time scales. The results show that drought duration and severity decreased over time in the Aibihu, Irtysh, Kaidu, Aksu, Yarkand, Hoton, Shule, Heihe (upstream), and Shiyang Rivers. However, the Tarim (upstream) and Heihe (middle stream) Rivers showed increasing drought duration and severity and this can be attributed to recent decades human activities. Furthermore, two correlation coefficient patterns between SSI and SPEI were found for the rivers of interest, an “increasing-decreasing” pattern for the Irtysh, Heihe, and Shiyang Rivers, where the precipitation is the main runoff supply, and an “increasing-stable” pattern for Aibihu and the Kaidu, Aksu, Yarkand, Hotan, and Shule Rivers, where glacier melt water provided a relatively high supply of runoff. Our findings are a contribution towards implementing effective water resources evaluation and planning in this arid region.

scholarly journals Quantifying human impacts on hydrological drought using a combined modelling approach in a tropical river basin in Central Vietnam

2017 ◽  
Author(s):  
A. B. M Firoz ◽  
Alexandra Nauditt ◽  
Manfred Fink ◽  
Lars Ribbe
Keyword(s):  
River Basin ◽  
Reservoir Operation ◽  
Human Impacts ◽  
Hydrological Drought ◽  
Drought Risk ◽  
Climatic Data ◽  
Strong Impact ◽  
Hydropower Development ◽  
Drought Duration ◽  
Central Vietnam

Abstract. Hydrological droughts are one of the most damaging disasters in terms of economic loss in Central Vietnam and other regions of South East Asia severely affecting agricultural production and drinking water supply. Their increasing frequency and severity can be attributed to extended dry spells and increasing water abstractions for e.g. irrigation and hydropower development to meet the demand of dynamic socioeconomic development. Based on hydro-climatic data for the period from 1980 to 2013 and reservoir operation data, the impacts of recent hydropower development and other alterations of the hydrological network on downstream streamflow and drought risk were assessed for a mesoscale basin of steep topography in Central Vietnam, the Vu Gia Thu Bon (VGTB) river basin. The Just Another Modelling System (JAMS)/J2000 was calibrated for the VGTB river basin to simulate reservoir inflow and the naturalized discharge time series for the downstream gauging stations. The HEC-ResSim reservoir operation model simulated reservoir outflow from eight major hydropower stations as well as the reconstructed streamflow for the main river branches Vu Gia and Thu Bon. Drought duration, severity and frequency was analysed for different time scales for the naturalized and reconstructed streamflow by applying the daily varying threshold method. Efficiency statistics for both models show good results. A strong impact of reservoir operation on downstream discharge at the daily, monthly, seasonal and annual scale was detected for four discharge stations relevant for downstream water allocation. In accordance with the reports from local stakeholders, we found a stronger hydrological drought risk for the anthropogenically impacted reconstructed streamflow. We conclude that the calibrated model setup provides a valuable tool to quantify the different origins of drought to support cross-sectorial water management and planning in a suitable way to be transferred to similar river basins.

scholarly journals Hydrological Drought Assessment Based on the Standardized Streamflow Index: A Case Study of the Three Cape Provinces of South Africa

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3498
Author(s):  
Christina M. Botai ◽  
Joel O. Botai ◽  
Jaco P. de Wit ◽  
Katlego P. Ncongwane ◽  
Miriam Murambadoro ◽  
...  
Keyword(s):  
South Africa ◽  
Water Resource Management ◽  
Hydrological Drought ◽  
Drought Severity ◽  
Drought Duration ◽  
Study Region ◽  
Drought Assessment ◽  
Return Levels ◽  
Drought Conditions ◽  
The Government

Global impacts of drought conditions pose a major challenge towards the achievement of the 2030 Sustainable Development Goals. As a result, a clarion call for nations to take actions aimed at mitigating the adverse negative effects, managing key natural resources and strengthening socioeconomic development can never be overemphasized. The present study evaluated hydrological drought conditions in three Cape provinces (Eastern, Western and Northern Cape) of South Africa, based on the Standardized Streamflow Index (SSI) calculated at 3- and 6-month accumulation periods from streamflow data spanning over the 3.5 decades. The SSI features were quantified by assessing the corresponding annual trends computed by using the Modified Mann–Kendall test. Drought conditions were also characterized in terms of the duration and severity across the three Cape provinces. The return levels of drought duration (DD) and drought severity (DS) associated with 2-, 5-, 10-, 20- and 50-year periods were estimated based on the generalized extreme value (GEV) distribution. The results indicate that hydrological drought conditions have become more frequent and yet exhibit spatial contrasts throughout the study region during the analyzed period. To this end, there is compelling evidence that DD and DS have increased over time in the three Cape provinces. Return levels analysis across the studied periods also indicate that DD and DS are expected to be predominant across the three Cape provinces, becoming more prolonged and severe during the extended periods (e.g., 20- and 50-year). The results of the present study (a) contribute to the scientific discourse of drought monitoring, forecasting and prediction and (b) provide practical insights on the nature of drought occurrences in the region. Consequently, the study provides the basis for policy- and decision-making in support of preparedness for and adaptation to the drought risks in the water-linked sectors and robust water resource management. Based on the results reported in this study, it is recommended that water agencies and the government should be more proactive in searching for better strategies to improve water resources management and drought mitigation in the region.

scholarly journals Understanding and seasonal forecasting of hydrological drought in the Anthropocene

2017 ◽  
Vol 21 (11) ◽  
pp. 5477-5492 ◽  
Author(s):  
Xing Yuan ◽  
Miao Zhang ◽  
Linying Wang ◽  
Tian Zhou
Keyword(s):  
River Basin ◽  
Yellow River ◽  
Hydrological Drought ◽  
Drought Severity ◽  
Drought Event ◽  
Drought Forecasting ◽  
Drought Frequency ◽  
Drought Duration ◽  
Groundwater Exploitation ◽  
Human Interventions

Abstract. Hydrological drought is not only caused by natural hydroclimate variability but can also be directly altered by human interventions including reservoir operation, irrigation, groundwater exploitation, etc. Understanding and forecasting of hydrological drought in the Anthropocene are grand challenges due to complicated interactions among climate, hydrology and humans. In this paper, five decades (1961–2010) of naturalized and observed streamflow datasets are used to investigate hydrological drought characteristics in a heavily managed river basin, the Yellow River basin in north China. Human interventions decrease the correlation between hydrological and meteorological droughts, and make the hydrological drought respond to longer timescales of meteorological drought. Due to large water consumptions in the middle and lower reaches, there are 118–262 % increases in the hydrological drought frequency, up to 8-fold increases in the drought severity, 21–99 % increases in the drought duration and the drought onset is earlier. The non-stationarity due to anthropogenic climate change and human water use basically decreases the correlation between meteorological and hydrological droughts and reduces the effect of human interventions on hydrological drought frequency while increasing the effect on drought duration and severity. A set of 29-year (1982–2010) hindcasts from an established seasonal hydrological forecasting system are used to assess the forecast skill of hydrological drought. In the naturalized condition, the climate-model-based approach outperforms the climatology method in predicting the 2001 severe hydrological drought event. Based on the 29-year hindcasts, the former method has a Brier skill score of 11–26 % against the latter for the probabilistic hydrological drought forecasting. In the Anthropocene, the skill for both approaches increases due to the dominant influence of human interventions that have been implicitly incorporated by the hydrological post-processing, while the difference between the two predictions decreases. This suggests that human interventions can outweigh the climate variability for the hydrological drought forecasting in the Anthropocene, and the predictability for human interventions needs more attention.

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