Evaluation and Bias Correction of CHIRP Rainfall Estimate for Rainfall-Runoff Simulation over Lake Ziway Watershed, Ethiopia

Goshime, Demelash Wondimagegnehu; Absi, Rafik; Ledésert, Béatrice

doi:10.3390/hydrology6030068

Cited by 50 publications

(43 citation statements)

References 37 publications

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“…Correlations between observed and simulated data were improved from 0.65, 0.76, and 0.60 to 0.78, 0.89, and 0.84 for rainfall, maximum and minimum temperatures, respectively. These results suggest that bias correction output is acceptable and consistent with the previous studies (Gebre and Ludwig 2015;Sisay et al 2017;Goshime et al 2019).…”

Section: Bias Correction Of Climate Variablesupporting

confidence: 91%

Modeling the Impact of Climate Change on Hydrological Responses in the Lake Tana Basin, Ethiopia

Teklay

Dile

Asfaw

et al. 2020

Preprint

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BackgroundHydrologic systems have been changing due to the impact of climate change and climate variability. The impacts of climate change are set to increase in the future due to the rise of global warming. Quantifying the impact of climate change on the spatial and temporal hydrological processes is important for integrated water resource management. The Lake Tana basin, which is the source of the Upper Blue Nile, is vulnerable to climate change and variability. This study was carried out in the four major tributary watersheds of the Lake Tana basin: Gilgel Abay, Gumara, Ribb, and Megech. The climate model and hydrological model was used to (i) to evaluate the performance of the Soil and Water Assessment Tool for study watershed, (ii) to assess the future rainfall and temperature variability and change in the study watershed, and (iii) to examine the impact of climate change on future watershed hydrology. The study used dynamically downscaled climate data for the baseline (2010–2015) and future period (2046–2051) under two Representative Concentration Pathways (RCP4.5 and RCP8.5). The climate scenarios were simulated using the Weather Research and Forecasting (WRF) model, with a 4-km horizontal resolution. A linear scaling method was applied to minimize model biases. The SWAT model was used to estimate the baseline and future hydrology using the bias-corrected climate data. ResultsThe performance of the SWAT model was ‘good’ to ‘very good’ for both the calibration and validation periods, with the Nash–Sutcliffe efficiency values between 0.71 to 0.92. The projected changes in rainfall vary with seasons and watershed under both scenarios. On average, annual rainfall may increase by 9.8% and 21.2% under RCP4.5 and RCP8.5 scenarios, respectively. Minimum temperature may rise by 1.68 °C and 2.26 °C while maximum temperature may increase by 1.65 °C and 2.75 °C under RCP4.5 and RCP8.5 scenarios, respectively. The changes in climate may cause an increase in surface runoff by 20.9% and 46.5% under RCP4.5 and RCP8.5 scenarios, respectively, while the evapotranspiration increase by 4.7% and 12.2% under RCP4.5 and RCP8.5, respectively. ConclusionThe findings provide valuable insights to implement appropriate water management strategies to mitigate and adapt to the negative impacts of climate change and variability on the Lake Tana basin, and other regions which have similar agro-ecology.

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Section: Bias Correction Of Climate Variablesupporting

confidence: 91%

Modeling the Impact of Climate Change on Hydrological Responses in the Lake Tana Basin, Ethiopia

Teklay

Dile

Asfaw

et al. 2020

Preprint

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Section: Methodsmentioning

confidence: 99%

“…In this study, lake areal rainfall is estimated from bias-corrected CHIRP rainfall estimate using rain gauge dataset as a reference. For a more detailed analysis of a bias correction approaches refer Goshime et al [21]. Lake open water evaporation was estimated from three representative stations (i.e.…”

Section: Lake Water Level Simulationmentioning

confidence: 99%

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Impact of Water Abstraction on the Water Level of Lake Ziway, Ethiopia

Goshime

Absi

Ledésert

et al. 2019

WIT Transactions on Ecology and the Environment

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Significant change has been observed in the water level of Lake Ziway in Ethiopia which hinders its services for a wide variety of ecosystems. However, the contribution of water withdrawal and its impact on the lake water level variation has not been quantified yet. In this study, we conducted a water abstraction survey (WAS) to estimate actual water withdrawal from the lake. Then, we applied a water balance model coupling with simulated river inflow from rainfall-runoff model output data to evaluate the isolated impact of water withdrawal on the lake water level from 1986-2000 at monthly time steps. The amount of water withdrawal from the lake for irrigation water use is 37 10 6 m 3 per year. This led to 0.36 m drop in the lake level which corresponded to 18 km 2 reductions in the lake surface area. This consequently resulted in a reduction of mean annual lake volume by 162 10 6 m 3 from 1986-2000, which accounts for 23% of the total lake inflow from rivers.The results indicate that abstraction from the lake is a significant contributor to the drop in water level of Lake Ziway. This calls for serious action on the management of water abstraction from the lake.

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“…We applied the hydrological model output coupling with water balance modelling and field surveys. The hydrological model output was based on calibrated and validated results from Goshime et al [21].The methodologies followed in this study are: First, we estimated water abstraction for all abstraction points based on Water Abstraction Survey (WAS). Next, we evaluated the water balance components of the lake under the natural condition on a monthly time steps.…”

Section: Methodsmentioning

confidence: 99%

Impact of water abstraction on water balance of Lake Ziway, Ethiopia

Wondimagegnehu¹,

Haile

Absi

et al. 2019

Proceedings of 4th International Electronic Conference on Water Sciences

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The available water volume of Lake Ziway in Ethiopia is declining at an alarming rate which hinders the lake services for a wide variety of sectors. However, there is a lack of systematic study to evaluate the contribution of water withdrawal by various sectors to the decline in the lake actual storage. In this study, we conducted a Water Abstraction Survey (WAS) to estimate actual water withdrawal from the lake. We applied a water balance model to evaluate the isolated impact of water withdrawal on the lake water volume and level. Three development pathways were simulated and the likely impact of these pathways on the lake water volume and level were assessed. Results indicate that water withdrawal for irrigation and domestic has significantly contributed to the change in the actual storage of Lake Ziway. Under full development pathways, irrigation water withdrawal from the lake is estimated to be 95.3 MCM. This will cause the mean annual water level of the lake to drop by 0.94 m, which yield with 38 km 2 reduction of the surface area of the lake. Overall, this will result in a reduction of mean annual lake volume by 405 MCM, which accounts for 26% of the average lake volume. Hence, our result indicates that the current impact of water abstraction on Lake Ziway storage is substantially large and will exacerbate in the future. This calls serious action on the management of water abstraction from the lake.

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Evaluation and Bias Correction of CHIRP Rainfall Estimate for Rainfall-Runoff Simulation over Lake Ziway Watershed, Ethiopia

Cited by 50 publications

References 37 publications

Modeling the Impact of Climate Change on Hydrological Responses in the Lake Tana Basin, Ethiopia

Modeling the Impact of Climate Change on Hydrological Responses in the Lake Tana Basin, Ethiopia

Impact of Water Abstraction on the Water Level of Lake Ziway, Ethiopia

Impact of water abstraction on water balance of Lake Ziway, Ethiopia

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