Your search found 5 records
1 McCartney, Matthew P.; Shiferaw, A.; Seleshi, Y.. 2008. Estimating environmental flow requirements downstream of the Chara Chara weir on the Blue Nile River. In Abtew, W.; Melesse, A. M. (Eds.). Proceedings of the Workshop on Hydrology and Ecology of the Nile River Basin under Extreme Conditions, Addis Ababa, Ethiopia, 16-19 June 2008. Sandy, UT, USA: Aardvark Global Publishing. pp.57-75.
Water management ; River basin management ; Ecology ; Rivers ; Environmental flows ; Environmental effects ; Downstream ; Weirs ; Hydrology ; Models ; Ecosystems ; Water power / Africa / Ethiopia / Sudan / Blue Nile River / Abay River / Chara Chara Weir / Lake Tana
(Location: IWMI HQ Call no: IWMI 577.64 G100 MCC Record No: H041346)
(1.27 MB)
Over the last decade flow in the Abay River (i.e., the Blue Nile) has been modified by operation of the Chara Chara weir and diversions to the Tis Abay hydropower stations, located downstream of the rivers source, Lake Tana. The most conspicuous impact of these human interventions has been significantly reduced flows over the Tis Issat Falls. This paper presents the findings of a hydrological study conducted to estimate environmental flow requirements downstream of the weir. The South African desktop reserve model was used to determine both high and low flow requirements in the reach containing the Falls. The results indicate that to maintain the basic ecological functioning in this reach requires an average annual allocation of 862 Mm3 (i.e. equivalent to 22% of the mean annual flow). Under natural conditions there was considerable seasonal variation, but the absolute minimum mean monthly allocation, even in dry years, should not be less than approximately 10 Mm3 (i.e. 3.7 m3s-1). These estimates make no allowance for maintaining the aesthetic quality of the Falls, which are popular with tourists. The study demonstrated that, in the absence of ecological information, hydrological indices can be used to provide a first estimate of environmental water requirements. However, to ensure proper management, much greater understanding of the relationships between flow and the ecological condition of the riverine ecosystem is needed.
2 Shiferaw, A.; McCartney, Matthew; Seleshi, Y.; Woldu, Z. 2008. Impacts of the Chara Chara Weir and environmental implications at the source of the Blue Nile River, Ethiopia. In Humphreys, E.; Bayot, R. S.; van Brakel, M.; Gichuki, F.; Svendsen, M.; Wester, P.; Huber-Lee, A.; Cook, S. Douthwaite, B.; Hoanh, Chu Thai; Johnson, N.; Nguyen-Khoa, Sophie; Vidal, A.; MacIntyre, I.; MacIntyre, R. (Eds.). Fighting poverty through sustainable water use: proceedings of the CGIAR Challenge Program on Water and Food, 2nd International Forum on Water and Food, Addis Ababa, Ethiopia, 10-14 November 2008. Vol.3. Water benefits sharing for poverty alleviation and conflict management; Drivers and processes of change. Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food. pp.75-78.
River basins ; Flow ; Weirs ; Dams ; Benefits ; Environmental impact assessment ; Social impact / Ethiopia / Blue Nile River / Tis Issat Falls / Chara Chara Weir / Lake Tana
(Location: IWMI HQ Call no: IWMI 333.91 G000 HUM Record No: H041680)
http://cgspace.cgiar.org/bitstream/handle/10568/3708/IFWF2_proceedings_Volume%20III.pdf?sequence=1
https://vlibrary.iwmi.org/pdf/H041680.pdf
https://vlibrary.iwmi.org/pdf/H041680.pdf
3 McCartney, Matthew; Shiferaw, A.; Seleshi, Y.. 2009. Estimating environmental flow requirements downstream of the Chara Chara weir on the Blue Nile River. Hydrological Processes, 23:3751-3758. [doi: https://doi.org/10.1002/hyp.7254]
Rivers ; Flow ; Ecosystems ; Dams ; Benefits ; Hydrology ; River basin management ; Models ; Environmental flows ; Water power ; Electrical energy ; Electricity supplies ; Water allocation / Ethiopia / Blue Nile River / Chara Chara weir / Tis Abay hydropower stations / Bahar Dar city / Tis Issat Falls / Lake Tana
(Location: IWMI HQ Call no: e-copy only Record No: H042242)
(0.20 MB)
Over the last decade, flow in the Abay River (i.e. the Blue Nile) has been modified by operation of the Chara Chara weir and diversions to the Tis Abay hydropower stations, located downstream. The most conspicuous impact of these human interventions is significantly reduced flows over the Tis Issat Falls. This paper presents the findings of a hydrological study conducted to estimate environmental flow requirements downstream of the weir. The Desktop Reserve Model (DRM) was used to determine both high and low flow requirements in the reach containing the Falls. The results indicate that to maintain the basic ecological functioning in this reach requires an average annual allocation of 862 Mm3 (i.e. equivalent to 22% of the mean annual flow). Under natural conditions there was a considerable seasonal variation, but the absolute minimum mean monthly allocation, even in dry years, should not be less than approximately 10 Mm3 (i.e. 3Ð7 m3 s1). These estimates make no allowance for maintaining the aesthetic quality of the Falls, which are popular with tourists. The study demonstrated that, in the absence of ecological information, hydrological indices can be used to provide a preliminary estimate of environmental flow requirements. However, to ensure proper management, much greater understanding of the relationships between flow and the ecological condition of the river ecosystem is needed.
4 Easton, Z. M.; Awulachew, Seleshi Bekele; Steenhuis, T. S.; Habte, S. A.; Zemadim, Birhanu; Seleshi, Y.; Bashar, K. E. 2012. Hydrological process in the Blue Nile. In Awulachew, Seleshi Bekele; Smakhtin, Vladimir; Molden, David; Peden D. (Eds.). The Nile River Basin: water, agriculture, governance and livelihoods. Abingdon, UK: Routledge - Earthscan. pp.84-111.
River basins ; Hydrological factors ; Rainfall-runoff relationships ; Watersheds ; Precipitation ; Infiltration ; Groundwater ; Water table ; Models ; Calibration ; Water balance ; Assessment ; Land use ; Land cover / Africa / Blue Nile River Basin
(Location: IWMI HQ Call no: IWMI Record No: H045313)
(2.14MB)
5 Alemu, A. M.; Seleshi, Y.; Meshesha, T. W. 2022. Modeling the spatial and temporal availability of water resources potential over Abbay River Basin, Ethiopia. Journal of Hydrology: Regional Studies, 44:101280. [doi: https://doi.org/10.1016/j.ejrh.2022.101280]
Water resources ; Water balance ; River basins ; Hydrological modelling ; Calibration ; Water yield ; Evapotranspiration ; Land use ; Land cover ; Watersheds ; Rain ; Sensitivity analysis / Ethiopia / Abbay River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H051531)
https://www.sciencedirect.com/science/article/pii/S2214581822002932/pdfft?md5=9bb4af3335275173ee03eda9dbe39f40&pid=1-s2.0-S2214581822002932-main.pdf
https://vlibrary.iwmi.org/pdf/H051531.pdf
https://vlibrary.iwmi.org/pdf/H051531.pdf
(11.80 MB) (11.8 MB)
Study region: Abbay River Basin, Ethiopia.
Study focus: This research focused on assessing the spatio-temporal availability and variability of water resources potential using physically based hydrological model. The availability and spatial variability of water balance components were modeled for each subbasins of Abbay River basin.
New hydrological insights for the region: Multi statistical performance criteria proved that ArcSWAT model has the capacity to reproduce flows that agree with the measured flows at daily time scale simulation and found as applicable over Abbay River basin. The Calibration and Validation were done at different subbasins. The result revealed that the performance of the model well improved as the basin was partitioned into subbasins. For reproduction of the measured flow at different flow segments, the model performed very good especially for high and peak flows segments. The rainfall distribution revealed that the basin is characterized by high spatial and temporal variation of rainfall. Three fourth of the annual rainfall was contributed from June to September. The water balance components analysis proved that Evapotranspiration is high over the basin which covers more than half (55.20 %) of the annual rainfall. Water yield (WYLD_Qmm) covers only 21.73 % of the annual rainfall. This research can be used as basis to give emphasis on water resources potential modeling in the future considering climate and land use changes.
Study focus: This research focused on assessing the spatio-temporal availability and variability of water resources potential using physically based hydrological model. The availability and spatial variability of water balance components were modeled for each subbasins of Abbay River basin.
New hydrological insights for the region: Multi statistical performance criteria proved that ArcSWAT model has the capacity to reproduce flows that agree with the measured flows at daily time scale simulation and found as applicable over Abbay River basin. The Calibration and Validation were done at different subbasins. The result revealed that the performance of the model well improved as the basin was partitioned into subbasins. For reproduction of the measured flow at different flow segments, the model performed very good especially for high and peak flows segments. The rainfall distribution revealed that the basin is characterized by high spatial and temporal variation of rainfall. Three fourth of the annual rainfall was contributed from June to September. The water balance components analysis proved that Evapotranspiration is high over the basin which covers more than half (55.20 %) of the annual rainfall. Water yield (WYLD_Qmm) covers only 21.73 % of the annual rainfall. This research can be used as basis to give emphasis on water resources potential modeling in the future considering climate and land use changes.
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