Estimating and interpreting hydrological drought indices using a selected catchment in Zimbabwe

Nyabeze, Washington R.

doi:10.1016/j.pce.2004.09.018

Cited by 22 publications

(17 citation statements)

References 5 publications

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“…Droughts are frequent in the Mzingwane catchment. According to Nyabeze [18,19], the 1:10 four-year drought affects the whole of Mzingwane while the 1:15 four-year drought would achieve 91% coverage of the catchment. The 1991/1992 drought in Mzingwane was somewhere between these two droughts.…”

Section: Description Of the Study Areamentioning

confidence: 99%

Linkages between local knowledge drought forecasting indicators and scientific drought forecasting parameters in the Limpopo River Basin in Southern Africa

Chisadza

Tumbare

Nyabeze

et al. 2015

International Journal of Disaster Risk Reduction

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Section: Description Of the Study Areamentioning

confidence: 99%

Linkages between local knowledge drought forecasting indicators and scientific drought forecasting parameters in the Limpopo River Basin in Southern Africa

Chisadza

Tumbare

Nyabeze

et al. 2015

International Journal of Disaster Risk Reduction

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“…When the variable of interest (x) (i.e., soil moisture, groundwater storage, or discharge) is below a predefined threshold (τ), a drought is assumed to have occurred. A constant or a threshold can be used, and because a variable threshold level takes seasonal patterns into account, it has been widely used [3,4]. The threshold is usually assumed to be equal to a given percentile of the flow duration curve between the 30 percentile flow (Q 30 ) and the 5percentile flow (Q 5 ) [5], or the threshold can be obtained by fitting some kind of statistical function through the data (normal, gamma, beta, etc.)…”

Section: Introductionmentioning

confidence: 99%

Uncertainty of Hydrological Drought Characteristics with Copula Functions and Probability Distributions: A Case Study of Weihe River, China

Zhao

Lü

et al. 2017

Water

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This study investigates the sensitivity and uncertainty of hydrological droughts frequencies and severity in the Weihe Basin, China during 1960-2012, by using six commonly used univariate probability distributions and three Archimedean copulas to fit the marginal and joint distributions of drought characteristics. The Anderson-Darling method is used for testing the goodness-of-fit of the univariate model, and the Akaike information criterion (AIC) is applied to select the best distribution and copula functions. The results demonstrate that there is a very strong correlation between drought duration and drought severity in three stations. The drought return period varies depending on the selected marginal distributions and copula functions and, with an increase of the return period, the differences become larger. In addition, the estimated return periods (both co-occurrence and joint) from the best-fitted copulas are the closet to those from empirical distribution. Therefore, it is critical to select the appropriate marginal distribution and copula function to model the hydrological drought frequency and severity. The results of this study can not only help drought investigation to select a suitable probability distribution and copulas function, but are also useful for regional water resource management. However, a few limitations remain in this study, such as the assumption of stationary of runoff series.

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“…Uhlenbrook et al, 2004). In southern Africa, where environmental and water stress is increasing (Nyabeze, 2004;Sivakumar et al, 2005), this type of understanding is essential in building resilience to large or catastrophic environmental changes and in developing trade-offs between food and economic production and ecosystem services (Falkenmark et al, 2007). It is also important for addressing broader humanitarian and development needs, through the many water intensive interventions that have been proposed by development agencies and projects (Love et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Rainfall–interception–evaporation–runoff relationships in a semi-arid catchment, northern Limpopo basin, Zimbabwe

Love

Uhlenbrook

Corzo

et al. 2010

Hydrological Sciences Journal

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Characterizing the response of a catchment to rainfall, in terms of the production of runoff vs the interception, transpiration and evaporation of water, is the first important step in understanding water resource availability in a catchment. This is particularly important in small semi-arid catchments, where a few intense rainfall events may generate much of the season's runoff. The ephemeral Zhulube catchment (30 km 2 ) in the northern Limpopo basin was instrumented and modelled in order to elucidate the dominant hydrological processes. Discharge events were disconnected, with short recession curves, probably caused by the shallow soils in the Tshazi sub-catchment, which dry out rapidly, and the presence of a dambo in the Gobalidanke sub-catchment. Two different flow event types were observed, with the larger floods showing longer recessions being associated with higher (antecedent) precipitation. The differences could be related to: (a) intensity of rainfall, or (b) different soil conditions. Interception is an important process in the water balance of the catchment, accounting for an estimated 32% of rainfall in the 2007/08 season, but as much as 56% in the drier 2006/07 season. An extended version of the HBV model was developed (designated HBVx), introducing an interception storage and with all routines run in semi-distributed mode. After extensive manual calibration, the HBVx simulation satisfactorily showed the disconnected nature of the flows. The generally low Nash-Sutcliffe coefficients can be explained by the model failing to simulate the two different observed flow types differently. The importance of incorporating interception into rainfall-runoff is demonstrated by the substantial improvement in objective function values obtained. This exceeds the gains made by changing from lumped to semi-distributed mode, supported by 1 000 000 Monte Carlo simulations. There was also an important improvement in the daily volume error. The best simulation, supported by field observations in the Gobalidanke sub-catchment, suggested that discharge was driven mainly by flow from saturation overland flow. Hortonian overland flow, as interpreted from field observations in the Tshazi subcatchment, was not simulated so well. A limitation of the model is its inability to address temporal variability in soil characteristics and more complex runoff generation processes. The model suggests episodic groundwater recharge with annual recharge of 100 mm year -1 , which is similar to that reported by other studies in Zimbabwe.Key words HBV; interception; Limpopo basin; semi-arid hydrologyRelations précipitation-interception-évaporation-écoulement dans un bassin versant semi-aride (nord du Limpopo, Zimbabwe) Résumé La caractérisation de la réponse d'un bassin versant aux précipitations, en termes de production d'écoulement par rapport à l'interception, la transpiration et l'évaporation, est un premier pas important pour la compréhension de la disponibilité des ressources en eau dans un bassin. Ceci est particulièrement im...

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Estimating and interpreting hydrological drought indices using a selected catchment in Zimbabwe

Cited by 22 publications

References 5 publications

Linkages between local knowledge drought forecasting indicators and scientific drought forecasting parameters in the Limpopo River Basin in Southern Africa

Linkages between local knowledge drought forecasting indicators and scientific drought forecasting parameters in the Limpopo River Basin in Southern Africa

Uncertainty of Hydrological Drought Characteristics with Copula Functions and Probability Distributions: A Case Study of Weihe River, China

Rainfall–interception–evaporation–runoff relationships in a semi-arid catchment, northern Limpopo basin, Zimbabwe

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