Hydrological Drought Analysis Research Articles

Frequency analysis of the extreme streamflow by the threshold level method in semi-arid region: Case study of Wadi Mekerra catchment in the North-West of Algeria

Abstract Extreme streamflow drought is the direct problem of serious on damaging and on social impacts, so the frequency analysis of hydrological drought is an important work can be done to studying the drought phenomenon in catchments. So the hydrometric data for a river conducts to the establishment of the flow duration curve (FDC) as an important index of streamflow drought regime, from this characteristic, a threshold level can be defined for both perennial or intermittent streams. Well, two partial duration series can be derived for each year; the deficit volume and drought duration series. In the catchment of Wadi Mekerra in the North-West of Algeria, the minimum value estimated from the Pareto’s annual maximum instantaneous flood population (0.60 m3∙s−1) is considered as the threshold level index where, the largest deficit volume and the largest drought duration occurring in a given year are taken into consideration. Hence, the frequency analysis of the streamflow drought regime of the catchment is analysed with Weibull distribution for both deficit volume and drought duration combined with the probability of occurrence which is determined under some criterion in order to forecasting the streamflow drought in the catchment.

Bivariate Frequency Analysis of Hydrological Drought Using a Nonstationary Standardized Streamflow Index in the Yangtze River

AbstractIn order to reassess the hydrological drought in the Yangtze River under changing environment, a nonstationary standardized streamflow index was proposed in this study to fit the streamflow...

Comparative analysis of meteorological and hydrological drought over the Pearl River basin in southern China

Abstract Drought is one of the major natural hazards with a possibly devastating impact on the regional environment, agriculture, and water resources. Previous studies have assessed the historic changes in meteorological drought over various regional scales but have rarely considered hydrological drought due to limited hydrological observations. Here, we use long-term (1960–2012) hydro-meteorological data to analyze the meteorological and hydrological drought comparatively in the Pearl River basin (PRB) in southern China using the standardized precipitation index (SPI) and the standardized runoff index (SRI). The results indicate a strong positive correlation between the SPI and SRI, and the correlation tends to be stronger at the longer timescale. The SPI is reliable to substitute for the SRI to represent the hydrological drought at the long-term scale (e.g., 12 months or longer). Trend analysis reveals a noticeably wetting trend mainly in the eastern regions and a significant drying trend mainly in the western regions and the downstream area of the PRB. The drought frequency is spatially heterogeneous and varies slightly at the interannual scale. Overall, the drought is dominated by noticeable cycles of shorter periodicity (0.75–1.8 years), and periodic cycles in the meteorological drought are mainly responsible for those in the hydrological drought.

Spatio-temporal Variation of Hydrological Drought in the Indo-Gangetic Plains

The Indo-Gangetic plains (IGP) encompass a large alluvial track consisting of multi-tier aquifer system. Due to stride developmental activities and intensification of agriculture with higher irrigation water requirement, shallow groundwater regime is getting depleted causing hydrological drought. Spatio-temporal variation of seasonal drought pattern and drought severity in the IGP region was analysed for the period of 2005-2009, using Standardized water level index (SWI) with topo to raster methods of interpolation in geographic information system (GIS). Analysis of hydrological drought indicated that 40-60 % area in the IGP was affected by mild hydrological drought, whereas 2-7 % of the area was affected by extreme hydrological drought because of excessive and indiscriminate groundwater pumping leading to decline in groundwater level. SWI categories were correlated with the irrigation activity for better irrigation planning. Irrigation planning for the IGP was suggested for different SWI drought categories.

Analysis of meteorological and hydrological drought based in SPI and SDI index in the Inaouen Basin (Northern Morocco)

Analysis of meteorological and hydrological drought based in SPI and SDI index in the Inaouen Basin (Northern Morocco)

Analysis of Impacts of Climate Change and Human Activities on Hydrological Drought: a Case Study in the Wei River Basin, China

Climate change and human activity are the two major drivers that can alter hydrological cycle processes and influence the characteristics of hydrological drought in river basins. The present study selects the Wei River Basin (WRB) as a case study region in which to assess the impacts of climate change and human activity on hydrological drought based on the Standardized Runoff Index (SRI) on different time scales. The Generalized Additive Models in Location, Scale and Shape (GAMLSS) are used to construct a time-dependent SRI (SRIvar) considering the non-stationarity of runoff series under changing environmental conditions. The results indicate that the SRIvar is more robust and reliable than the traditional SRI. We also determine that different driving factors can influence the hydrological drought evolution on different time scales. On shorter time scales, the effects of human activity on hydrological drought are stronger than those of climate change; on longer time scales, climate change is considered to be the dominant factor. The results presented in this study are beneficial for providing a reference for hydrological drought analysis by considering non-stationarity as well as investigating how hydrological drought responds to climate change and human activity on various time scales, thereby providing scientific information for drought forecasting and water resources management over different time scales under non-stationary conditions.

Spatial delineation of riparian groundwater within alluvium deposit of mountainous region using Laplace equation

AbstractThe interaction between surface and groundwater plays a key role in a riparian ecosystem while the size of riparian groundwater has not been typically incorporated into hydrological modelling systems. An extensive geophysical survey composed of 25 individual DC electrical resistivity profiles was conducted at the Blair–Wallis site in Wyoming. The observed resistivity images show a near‐surface aquifer interpreted as the saturated alluvium deposit along the channel, rather than the geological bedrock. Based on the electrical resistivity images, it can be inferred that only the near‐surface portion of the groundwater actively interacts with the stream flow in the mountainous and hilly watershed. This study attempted the spatial extrapolation of the measured riparian aquifer depths by means of fitting functions based on the surface topography. The analysis indicated that the boundary of the riparian aquifer well corresponds to the topographical inflexion point of the hill slope profile. It was also demonstrated that the extent of alluvium deposit, where the area of riparian aquifer is indicated, can be delineated using the slope and curvature maps in the geographic information system. Then, the parabolic and biharmonic functions were tested for the groundwater depth estimation using the developed alluvium deposit map. The proposed methodology was effective if geological diffusion processes by wind and water dominated the topography. The spatial map of the active aquifer will be useful in hydrological drought analysis because it is considered to be a main source of baseflow during dry seasons.

Analysis of hydrological drought characteristics using copula function approach

Drought is a natural phenomenon which starts with decreased precipitation and can disrupt the environmental systems by changing the hydrological cycle. This is more conspicuous in hydrological drought. In analysis of hydrological drought, two factors of severity (intensity) and duration play eminent role. These characteristics are highly related and therefore their combined analysis contributes to better understanding of the drought situation. In this research, by using 40-year (1974–2014) daily discharge data of Tajan River, located in Mazandaran province, Iran, and low-flow indices, the best evaluation index of hydrological drought was determined and 10 past hydrological drought events in the region were identified. Then, the best statistical distribution of both drought variables (duration and severity) was selected, based on the goodness-of-fit tests. Five copula functions were fitted to the data. Results showed that Galambos function with the highest maximum log-likelihood (− 8.934) was selected as the best copula function. Results of the bivariate (duration and severity) statistical distribution could be used to analyze the probability of hydrological drought in the region. This bivariate and conditional probability for the worst drought, with duration of 5 months and severity of 0.32, was 6.1 and 28.5%, respectively.

National-scale analysis of simulated hydrological droughts (1891–2015)

Droughts are phenomena that affect people and ecosystems in a variety of ways. One way to help with resilience to future droughts is to understand the characteristics of historic droughts and how these have changed over the recent past. Although, on average, Great Britain experiences a relatively wet climate it is also prone to periods of low rainfall which can lead to droughts. Until recently research into droughts of Great Britain has been neglected compared to other natural hazards such as storms and floods. This study is the first to use a national-scale gridded hydrological model to characterise droughts across Great Britain over the last century. Firstly, the model performance at low flows is assessed and it is found that the model can simulate low flows well in many catchments across Great Britain. Next, the threshold level method is applied to time series of monthly mean river flow and soil moisture to identify historic droughts (1891–2015). It is shown that the national-scale gridded output can be used to identify historic drought periods. A quantitative assessment of drought characteristics shows that groundwater-dependent areas typically experience more severe droughts, which have longer durations rather than higher intensities. There is substantial spatial and temporal variability in the drought characteristics, but there are no consistent changes through time.

Analysis of meteorological and hydrological droughts in the Niger-South Basin, Nigeria

Information gained from drought analysis can serve as the basis for water resources planning and management under the prevailing climate change condition especially at the basin scale. The aim of this work is to apply two meteorological drought indices - Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI) and a hydrological drought index - Standardized Runoff Index (SRI) to investigate the occurrence of drought in the Niger-South Basin (NSB), a sub-catchment of the Niger River Basin in Nigeria, during the period 1970–2008. The results showed that the period between 1970 and 1981 was dominated by wet conditions; second, from 1982 to 1998, a period of droughts ranging from moderate dry to extreme dry alternated with moderate wet conditions, while the third period beginning from 1999 to 2008 displayed another round of severe droughts sparingly intercepted by occasional moderate wet conditions. High correlation values of between 0.66 (at 3-month scale) and 0.56 (at 12-month scale) show comparativeness in the performance of the two drought indices. For the hydrological drought, a severe drought was observed in 1982 and near normal and moderately wet since 1997. The higher agreement between the SRI and SPEI, suggests that hydrological droughts are more affected by temperature (warming) than precipitation (drying) in the basin. Further analysis of the frequency of the various conditions shows that it has been more of near normal conditions (>60%), while extremely dry and wet conditions (2% each) have been very rare. However, given the projected global warming conditions, a reversal of the present normal condition might be witnessed in the nearest future, hence, the results of this study can serve as a basis for effective water resources planning and management in the basin.

Meteorological and hydrological drought analysis of the Seyhan−Ceyhan River Basins, Turkey

ABSTRACTThe increase in concern about drought in the Seyhan−Ceyhan River Basins in Turkey has brought about the need to define temporal and spatial drought variations. Unlike previous studies that cover this region in the current literature, sufficient amounts of data from 14 meteorological and 12 streamflow stations are used in the form of 3, 6 and 12 month timescales allowing both meteorological and hydrological drought analyses to be conducted in detail. The standardized precipitation index and streamflow drought index methods are employed for the drought analyses presented. The location, period and occurrence level of drought events for this region are specified and presented graphically. The correlation between hydrological and meteorological droughts suggests that there is a specific lag time for the droughts such that a meteorological drought emerges in the following year as a hydrological drought. Accordingly, the predicted hydrological drought period may allow for better planning of the efficient use of water resources and hydroelectric and agricultural production in this region.

Multi-time-scale analysis of hydrological drought forecasting using support vector regression (SVR) and artificial neural networks (ANN)

In this study, the preprocessing of the gamma test was used to select the appropriate input combination into two models including the support vector regression (SVR) model and artificial neural networks (ANNs) to predict the stream flow drought index (SDI) of different timescales (i.e., 3, 6, 9, 12, and 24 months) in Latian watershed, Iran, which is one of the most important sources of water for the large metropolitan Tehran. The variables used included SDIt, SDIt − 1, SDIt − 2, SDIt − 3, and SDIt − 4 monthly delays. Two variables including SDIt and SDIt − 1 with lower gamma values were identified as the most optimal combination of variables in all drought timescales. The results showed that the gamma test was able to correctly identify the right combination for the forecasting of 6, 9, and 12 months SDI using the ANN model. Also, the gamma test was considered in selecting the appropriate inputs for identifying the values of 9, 12, and 24 months SDI in SVR. The support vector machine approach showed a better efficiency in the forecast of long-term droughts compared to the artificial neural network. In total, among forecasts made for 30 scenarios, the support vector machine model only in scenario 3 of SDI3, scenario 1 of SDI6, and scenarios 2 and 3 of SDI24 represented poorer efficiency compared to the artificial neural network (MLP layer), but in other scenarios, the results of SVR had better efficiency.

Bivariate Drought Analysis Using Streamflow Reconstruction with Tree Ring Indices in the Sacramento Basin, California, USA

Long-term streamflow data are vital for analysis of hydrological droughts. Using an artificial neural network (ANN) model and nine tree-ring indices, this study reconstructed the annual streamflow of the Sacramento River for the period from 1560 to 1871. Using the reconstructed streamflow data, the copula method was used for bivariate drought analysis, deriving a hydrological drought return period plot for the Sacramento River basin. Results showed strong correlation among drought characteristics, and the drought with a 20-year return period (17.2 million acre-feet (MAF) per year) in the Sacramento River basin could be considered a critical level of drought for water shortages.

Spatio-temporal Analysis of Hydrological Drought at Catchment Scale Using a Spatially-distributed Hydrological Model

Lately, drought is more intense and much more severe around the globe, causing more deaths than other hazards in the past century. Drought can be characterized quantitatively for its spatial extent, intensity and duration by using drought indicators. Several indicators have been developed in order to characterize drought, being the most widespread the Standardized Precipitation Index (SPI). Nevertheless, due to its known limitations, other indicators have been proposed. In this paper, evaporation and runoff simulations of a basin were used to evaluate the variation and performance of different meteorological and hydrological drought indicators in identifying drought. Daily simulations of evaporation and runoff were computed by using a distributed hydrological model of a catchment located in the southeast of Mexico. After calibration of the hydrological model, we calculated at different time steps the drought indicators: Standardized Precipitation Index (SPI), Standardized Precipitation Evaporation Index (SPEI), Evapotranspiration Deficit Index (ETDI), Standardized Evapotranspiration Deficit Index (SEDI) and Standardized Runoff Index (SRI). Furthermore, the so-called Non-Contiguous Drought Analysis (NCDA) was carried out to compare the skill of each indicator to identify drought. Results show that meteorological drought indicators do not identify all drought events for the time steps of 1 and 3 months. For 3-, 6- and 9-month time steps, meteorological drought indicators tend to identify the onset with a lag. For long-time steps of 12 and 24, the use of agricultural and hydrological droughts indicators is recommended, since these indicators can identify prolonged drought periods. The results suggest that for a better monitoring of drought in a catchment, it is important the joint evaluation and the use of not only meteorological drought indicators but also hydrological and agricultural ones, in order to identify drought events and their spatio-temporal evolution.

At-site hydrological drought analysis: Case study of Velika Morava River at Ljubicevski most (Serbia)

At-site frequency analysis of hydrological droughts is presented in this paper, in the example of the hydrological station Ljubicevski Most on the Velika Morava River, which represents the outlet of the entire Velika Morava basin, covering 42% of the Republic of Serbia. It is the first time that for the Velika Morava basin, and Serbia, theoretical distributions of deficit and duration of hydrological droughts are chosen according to best fit to empirical data, and not according to chosen in advance distributions, which has been the case until now. Also, for the first time in Serbia the method of L-moments was used for parameter estimation of distributions for extreme value modeling of hydrological drought characteristics. These improvements of existing method should contribute to better estimation of hydrological drought of large return period. The hydrological droughts were selected by threshold level method using daily data for the period 1960–2014, and their characteristics, deficits and durations of droughts were analyzed by method of partial duration series (peak over threshold). The results of calculations indicate that the best fit with the empirical data of deficit volumes has the model with binomial distribution of number of drought occurrences and Weibull distribution of exceedance magnitudes (B+W), and with drought durations model with binomial distribution of number of drought occurrences and exponential distribution of exceedance magnitudes (B+E). Based on the chosen distribution it is possible to calculate exceedance probabilities, i.e. return periods of deficit volumes and durations of largest observed droughts, like the 1993 drought, or to estimate 10-, 20-, 50- and 100-year droughts.

Uncertainty evaluation of copula analysis of hydrological droughts in the East River basin, China

The joint probability behaviors of extreme hydro-meteorological events, such as droughts, have been receiving increasing attentions in recent years. Since extreme hydro-meteorological events are reflected by more than one variable, such as duration and intensity, copula functions have been widely applied. However, uncertainties of copula-based analysis of hydrological droughts as a result of selection of marginal distribution and copulas have not yet received significant concerns. The aim of this study is to evaluate such uncertainties based on Bayesian approach. The method is used to analyze hydrological drought in the East River basin (China), which is the principal supplier of water resources for megacities in the Pearl River Delta and also for Hong Kong. The results indicate that the credible intervals of most likely design drought events with a return period of 20years in terms of drought severity and duration are considerably large at all stations in the East River basin, covering the drought event curves at return periods of 10 and 50years. Also the influences of heavy-tailed marginal distribution on the uncertainty evaluation of joint distribution have been investigated. Results show that the stronger the heavy-tailed marginal distribution, the greater the uncertainty of the joint distribution, especially for the extreme event. Results of this study provide a technical reference for uncertainty evaluation in copula-based analysis of drought events at regional and global scales. The large credible interval of drought severity and duration greatly challenges measures of mitigation of drought hazards and water resource management.

Water Harvesting: A Potential Means for Water Security in the Far North Region of Cameroon

The role of water harvesting as a strategy in adapting to the current climatic variability and change has really not been exploited in the Far North region of Cameroon. The region is threatened by water shortage and climate variability. This paper seeks to emphasize the availability of sufficient water which could be harvested to ensure water security for both domestic and agricultural purposes. Temperature and precipitation data between the years of 1957 and 2006 were analyzed to observe their different trends across these years. Standardized precipitation index (SPI) was then computed to determine the hydrological drought trend for the region. Remote sensing techniques were used to compare land use and land cover dynamics between 1987 and 2005. The obtained results show that temperature seems to remain constant but rainfall has decreased; however, the amount of rainfall is significantly high when compared with other regions with little or no water problem. The hydrological drought analysis using SPI shows a downward trend but did not depict severe drought conditions in the area. And applying the Mann–Kendall trend analysis revealed that there was no statistically significant change with the overall downward SPI, temperature, and rainfall trends. Furthermore, the remote sensing studies revealed an increase in vegetation, water resources, and settlement, whereas a decrease was observed in the total area covered by farmlands and bare soils. The paper concluded by proposing recommendations to ensure water security for both domestic and agriculture purposes in the study area.

Hydrological Drought at Dongting Lake: Its Detection, Characterization, and Challenges Associated With Three Gorges Dam in Central Yangtze, China

The hydrological drought analysis at Dongting Lake is important for clarifying some of the most complex hydrological issues in relation to the intertwined interactions of a lake-river-reservoir system from the operation of Three Gorges Dam (TGD) located upstream of the central Yangtze River. The assessment metrics for a hydrological drought were established according to the exposed wetlands associated with ecological impacts, and used to determine the characteristic water level for the occurrence and severity of drought. The causal effects of a hydrological drought were analyzed based on the hydrological regimes across lake areas, and the drought impact from the flow regulation in the TGD was evaluated by using a neural network model. The hydrological systems analysis indicates that: 1) the frequency, severity and causes of hydrological droughts varied for different lake areas and seasons due to the specific basin morphology and the deviation of water regimes; 2) the water storage in the Three Gorges Reservoir has advanced the exposed time of wetlands, and has prolonged the autumn drought by approximately 30 %. However, the modeling also reveals that the regular operation of the TGD did not change the natural drought trends at Dongting Lake, and it is not deemed as the primary cause of recent hydrological droughts.

Hydrological Drought Analysis of Karkheh River Basin in Iran Using Variable Threshold Level Method

Drought is an important phenomenon in recent years which caused a lot of problems for most of areas in Iran. Drought lead to water scarcity for people and this problem becomes one of the important challenges for the country. Karkheh River basin is one of the considerable water resources field in Iran and it is located in west parts of Iran. Current paper tries to take one step ahead toward scientific and practical drought management in Karkheh basin by analyzing hydrological drought. In this paper using daily discharge time series of 13 hydrometric stations which are located in the basin and also applying threshold level method, dry periods were extracted and results were analyzed. Results showed that the most volume and the most duration of drought in threshold level of 70% mostly happened within 1998-2000 and 2006-2008. Also the results of the frequency analysis of drought parameters indicted that for maximum deficit volume series Weibull distribution and Generalized Pareto Distribution (GP) in accordance with 77% of stations and for maximum duration series, GP distribution in accordance with 54% of stations had the most consistency. Based on this consistency, return period of droughts were also computed and the possibility of drought predictions in future was determined.

Hydrological Drought Analysis in Namhan River Basin, Korea

AbstractAnalysis and forecasting of droughts are important for water resources management. The objective of this study is to analyze hydrological droughts using the joint drought probability distribution derived from the copula theory and analyze drought return periods upstream of Namhan River in the upper Han River basin, Korea. Results of the study shows that the severest drought that occurred from 1981 to 1982 has a 110-year return period.