A grid-based runoff generation and flow routing model for the Upper Blue Nile basin

Mishra, Anil Kumar; Hata, Takeshi

doi:10.1623/hysj.51.2.191

Cited by 21 publications

(14 citation statements)

References 41 publications

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“…However, the available hydrological data are limited (for example, presently about 42 % of the Lake Tana sub-basin, the source of the Blue Nile, is gauged by the Ministry of Water Resources of Ethiopia). Furthermore, research efforts performed so far in the Upper Blue Nile Basin with respect to the basin characteristics, hydrology and climatic conditions are scanty and fragmented (Johnson and Curtis, 1994;Conway, 1997;Mishra and Hata, 2006;Antar et al, 2006). Hydrological models that allow for a description of the hydrology of the region play an important role in predicting river discharges from ungauged catchments and understanding the rainfall-runoff processes in the catchments in order to enhance hydrological and water resources analysis.…”

Section: Introductionmentioning

confidence: 99%

“…Hydrological models that allow for a description of the hydrology of the region play an important role in predicting river discharges from ungauged catchments and understanding the rainfall-runoff processes in the catchments in order to enhance hydrological and water resources analysis. As such, a number of models have been developed and applied to study the water balance, soil erosion, climate and environmental changes in the Blue Nile Basin (e.g., Johnson and Curtis, 1994;Conway, 1997;Mishra and Hata, 2006;Kebede et al, 2006;Kim and Kaluarachchi, 2008;Collick et al, 2009;Steenhuis et al, 2009;Tekleab et al, 2011;Tilahun et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Analyzing runoff processes through conceptual hydrological modeling in the Upper Blue Nile Basin, Ethiopia

Dessie

Verhoest

Pauwels

et al. 2014

Hydrol. Earth Syst. Sci.

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Abstract. Understanding runoff processes in a basin is of paramount importance for the effective planning and management of water resources, in particular in data-scarce regions such as the Upper Blue Nile. Hydrological models representing the underlying hydrological processes can predict river discharges from ungauged catchments and allow for an understanding of the rainfall-runoff processes in those catchments. In this paper, such a conceptual process-based hydrological model is developed and applied to the upper Gumara and Gilgel Abay catchments (both located within the Upper Blue Nile Basin, the Lake Tana sub-basin) to study the runoff mechanisms and rainfall-runoff processes in the basin. Topography is considered as a proxy for the variability of most of the catchment characteristics. We divided the catchments into different runoff production areas using topographic criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in the Upper Blue Nile Basin) were considered separately in the conceptual model. Based on model results, it can be inferred that about 65 % of the runoff appears in the form of interflow in the Gumara study catchment, and baseflow constitutes the larger proportion of runoff (44-48 %) in the Gilgel Abay catchment. Direct runoff represents a smaller fraction of the runoff in both catchments (18-19 % for the Gumara, and 20 % for the Gilgel Abay) and most of this direct runoff is generated through infiltration excess runoff mechanism from the impermeable rocks or hard soil pans. The study reveals that the hillslopes are recharge areas (sources of interflow and deep percolation) and direct runoff as saturated excess flow prevails from the flat slope areas. Overall, the model study suggests that identifying the catchments into different runoff production areas based on topography and including the impermeable rocky areas separately in the modeling process mimics the rainfall-runoff process in the Upper Blue Nile Basin well and yields a useful result for operational management of water resources in this data-scarce region.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analyzing runoff processes through conceptual hydrological modeling in the Upper Blue Nile Basin, Ethiopia

Dessie

Verhoest

Pauwels

et al. 2014

Hydrol. Earth Syst. Sci.

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“…Both Mishra and Hata (2006) and Conway (1997) developed useful results with grid-based water balance models for the Blue Nile Basin using monthly discharge data from the El Deim Station in Sudan, located close to the Ethiopian border. They were studying the spatial variability of flow parameters and the sensitivity of runoff to changes in climate.…”

Section: Introductionmentioning

confidence: 99%

Predicting discharge and sediment for the Abay (Blue Nile) with a simple model

Steenhuis

Collick

Easton

et al. 2009

Hydrological Processes

129

160

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Models accurately representing the underlying hydrological processes and sediment dynamics in the Nile Basin are necessary for optimum use of water resources. Previous research in the Abay (Blue Nile) has indicated that direct runoff is generated either from saturated areas at the lower portions of the hillslopes or from areas of exposed bedrock. Thus, models that are based on infiltration excess processes are not appropriate. Furthermore, many of these same models are developed for temperate climates and might not be suitable for monsoonal climates with distinct dry periods in the Nile Basin. The objective of this study is to develop simple hydrology and erosion models using saturation excess runoff principles and interflow processes appropriate for a monsoonal climate and a mountainous landscape. We developed a hydrology model using a water balance approach by dividing the landscape into variable saturated areas, exposed rock and hillslopes. Water balance models have been shown to simulate river flows well at intervals of 5 days or longer when the main runoff mechanism is saturation excess. The hydrology model was developed and coupled with an erosion model using available precipitation and potential evaporation data and a minimum of calibration parameters. This model was applied to the Blue Nile. The model predicts direct runoff from saturated areas and impermeable areas (such as bedrock outcrops) and subsurface flow from the remainder of the hillslopes. The ratio of direct runoff to total flow is used to predict the sediment concentration by assuming that only the direct runoff is responsible for the sediment load in the stream. There is reasonable agreement between the model predictions and the 10-day observed discharge and sediment concentration at the gauging station on Blue Nile upstream of Rosaries Dam at the Ethiopia-Sudan border

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“…Johnson and Curtis, 1994;Conway, 1997;Mishra and Hata, 2006;Steenhuis et al, 2009). However, most of these studies were conducted on large scale to analyze the flow at the outlet at the Published by Copernicus Publications on behalf of the European Geosciences Union.…”

Section: Introductionmentioning

confidence: 99%

Water balance modeling of Upper Blue Nile catchments using a top-down approach

Tekleab

Uhlenbrook

Mohamed

et al. 2011

Hydrol. Earth Syst. Sci.

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Abstract. The water balances of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach based on Budyko's hypotheses. The objective of this study is to obtain better understanding of water balance dynamics of upper Blue Nile catchments on annual and monthly time scales and on a spatial scale of meso scale to large scale. The water balance analysis using a Budykotype curve at annual scale reveals that the aridity index does not exert a first order control in most of the catchments. This implies the need to increase model complexity to monthly time scale to include the effects of seasonal soil moisture dynamics. The dynamic water balance model used in this study predicts the direct runoff and other processes based on the limit concept; i.e. for dry environments since rainfall amount is small, the aridity index approaches to infinity or equivalently evaporation approaches rainfall and for wet environments where the rainfall amount is large, the aridity index approaches to zero and actual evaporation approaches the potential evaporation. The uncertainty of model parameters has been assessed using the GLUE (Generalized Likelihood Uncertainty Estimation) methodology. The results show that the majority of the parameters are reasonably well identifiable. However, the baseflow recession constant was poorly identifiable. Parameter uncertainty and model structural errors could be the reason for the poorly identifiable parameter. Moreover, a multi-objective model calibration strategy has been employed to emphasize the different aspects of the hydrographs on low and high flows.Correspondence to: S. Tekleab (siraktekleab@yahoo.com)The model has been calibrated and validated against observed streamflow time series and it shows good performance for the twenty study catchments in the upper Blue Nile. During the calibration period (1995)(1996)(1997)(1998)(1999)(2000) the Nash and Sutcliffe efficiency (E NS ) for monthly flow prediction varied between 0.52 to 0.93 (dominated by high flows), while it varied between 0.32 to 0.90 using logarithms of flow series (indicating the goodness of low flow simulations). The model is parsimonious and it is suggested that the calibrated parameters could be used after some more regionalization efforts to predict monthly stream flows in ungauged catchments of the Upper Blue Nile basin, which is the vast majority of catchments in that region.

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A grid-based runoff generation and flow routing model for the Upper Blue Nile basin

Cited by 21 publications

References 41 publications

Analyzing runoff processes through conceptual hydrological modeling in the Upper Blue Nile Basin, Ethiopia

Analyzing runoff processes through conceptual hydrological modeling in the Upper Blue Nile Basin, Ethiopia

Predicting discharge and sediment for the Abay (Blue Nile) with a simple model

Water balance modeling of Upper Blue Nile catchments using a top-down approach

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