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Lake Ziway, the only freshwater lake in Ethiopia’s Central Rift Valley basin, has been the source for irrigation, floriculture, fish farming and domestic water supply in the region for the last few decades. This study examined the impacts of the planned future agricultural developments and climate change on the lake water balance by an integrated application of the Soil Water Assessment Tool and Water Evaluation and Planning models. The future projections of precipitation and temperature from the Coordinated Regional Downscaling Experiment, CORDEX-AFRICA, under the Representative Concentration Pathways 4.5 and 8.5 were used for the climate change impact assessment. Nine irrigation development and climate change scenarios were developed and simulated to examine the separate and combined impacts on the lake water balance and supply coverages. The study showed that the planned future agricultural developments could result in a mean annual lake water level decline by about 0.15 m, with a considerable reduction (27% to 32%) in the outflow to the downstream Bulbula River. Climate change could increase evaporation losses from the shallow lake resulting in a drastic decrease in the lake water level, especially during the dry season. It could also significantly reduce (by about 74%) the amount of water flowing out of the lake. The combined impacts of future development and climate change are likely to reduce the supply coverages of most of the competing demands. Approaches need to be studied to minimize the lake water evaporation losses and explore water demand/supply management options.
Mulugeta Musie; Andrea Momblanch; Sumit Sen. Exploring future global change-induced water imbalances in the Central Rift Valley Basin, Ethiopia. Climatic Change 2021, 164, 1 -19.
AMA StyleMulugeta Musie, Andrea Momblanch, Sumit Sen. Exploring future global change-induced water imbalances in the Central Rift Valley Basin, Ethiopia. Climatic Change. 2021; 164 (3):1-19.
Chicago/Turabian StyleMulugeta Musie; Andrea Momblanch; Sumit Sen. 2021. "Exploring future global change-induced water imbalances in the Central Rift Valley Basin, Ethiopia." Climatic Change 164, no. 3: 1-19.
Lake Ziway sub-basin, Central Rift Valley basin, Ethiopia. This study evaluated the applicability of the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) and the Coordinated Regional Downscaling Experiment (CORDEX-AFRICA) datasets for climate change impact assessment. It also evaluated the hydrologic impact of climate change in the sub-basin. The hydrologic model Soil and Water Assessment Tool (SWAT) was forced with the climate datasets to simulate the reference and future period streamflows under RCP 4.5 and RCP 8.5 scenarios. The seasonality and volumetric deviations of the average annual streamflows simulated using the climate models were used as criteria for selecting members of the ensemble. All the climate models in the bias-corrected NEX-GDDP datasets failed to satisfy the criteria. The ensemble average annual streamflows, simulated using the CORDEX-AFRICA dataset, are expected to increase towards the end of the century under both the climate scenarios. However, the ensemble average dry season streamflows are projected to decrease during the mid- and end-periods of the century. The expected decreases in streamflows during the dry and pre-wet seasons, along with excessive abstractions of water from Lake Ziway, would exacerbate water scarcity in the basin. Approaches need to be developed to capture the increase in water availability during the wet season to alleviate water scarcity during the dry season.
Mulugeta Musie; Sumit Sen; Puneet Srivastava. Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia. Journal of Hydrology: Regional Studies 2020, 31, 100721 .
AMA StyleMulugeta Musie, Sumit Sen, Puneet Srivastava. Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia. Journal of Hydrology: Regional Studies. 2020; 31 ():100721.
Chicago/Turabian StyleMulugeta Musie; Sumit Sen; Puneet Srivastava. 2020. "Application of CORDEX-AFRICA and NEX-GDDP datasets for hydrologic projections under climate change in Lake Ziway sub-basin, Ethiopia." Journal of Hydrology: Regional Studies 31, no. : 100721.
Hydrological impacts of human activities and climate variability on Ketar and Meki watersheds of Lake Ziway basin, Ethiopia were studied using the soil and water assessment tool. Three land-use change and two climate variability scenarios were considered to analyze the separate and combined impacts on annual water balance, monthly streamflow, and spatial distributions of evapotranspiration and water yield. The evaluation showed that changes in land use resulted in an increase in annual surface runoff and water yield for Ketar watershed and an increase in annual ET for Meki. Similarly, the climate variability resulted in a decrease in annual ET, surface runoff, and water yield for Ketar watershed and a decrease in ET for Meki. Overall, climate variability has greater impacts on the monthly streamflow compared to land-use change impacts. Similarly, greater sensitivity in hydrologic response was observed for Ketar watershed compared to Meki watershed.
Mulugeta Musie; Sumit Sen; Indrajeet Chaubey. Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia. Water 2020, 12, 164 .
AMA StyleMulugeta Musie, Sumit Sen, Indrajeet Chaubey. Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia. Water. 2020; 12 (1):164.
Chicago/Turabian StyleMulugeta Musie; Sumit Sen; Indrajeet Chaubey. 2020. "Hydrologic Responses to Climate Variability and Human Activities in Lake Ziway Basin, Ethiopia." Water 12, no. 1: 164.
The objective of this study was to evaluate the hydrologic performance of gridded precipitation datasets for streamflow simulation in Ethiopia. Four products are prominent in the literature, namely Climate Forecast System Reanalysis (CFSR), Climate Hazards Group Infra-Red Precipitation with Station (CHIRPS), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR), and Tropical Rainfall Measuring Mission (TRMM) 3B42 Version 7 (3B42V7). The datasets from these products were compared statistically with the gauge observation dataset. Furthermore, the hydrologic performance of the products was evaluated using the Soil and Water Assessment Tool (SWAT) hydrologic model in two watersheds of the Lake Ziway basin. Four statistical and three contingency indices were used to compare the precipitation products statistically, and Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS) and the ratio of mean square error (RSR) were used to compare streamflow simulations. All the satellite-based precipitation products (CHIRPS, PERSIANN-CDR, and TRMM) performed well for monthly streamflow simulations for both watersheds. The reanalysis product CFSR performed the worst with high mean error (ME) and relative bias ratio (BIAS). The high ME and BIAS values of CFSR adversely affected the hydrologic performance and resulted in unsatisfactory streamflow simulation. Performance of the CHIRPS precipitation product in capturing daily and monthly streamflows showed that it can provide valuable precipitation estimates for use as input in hydrologic models in data-sparse regions of developing countries such as Ethiopia.
Mulugeta Musie; Sumit Sen; Puneet Srivastava. Comparison and evaluation of gridded precipitation datasets for streamflow simulation in data scarce watersheds of Ethiopia. Journal of Hydrology 2019, 579, 124168 .
AMA StyleMulugeta Musie, Sumit Sen, Puneet Srivastava. Comparison and evaluation of gridded precipitation datasets for streamflow simulation in data scarce watersheds of Ethiopia. Journal of Hydrology. 2019; 579 ():124168.
Chicago/Turabian StyleMulugeta Musie; Sumit Sen; Puneet Srivastava. 2019. "Comparison and evaluation of gridded precipitation datasets for streamflow simulation in data scarce watersheds of Ethiopia." Journal of Hydrology 579, no. : 124168.