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Hydrological response to climate change for Gilgel Abay River, in the Lake Tana Basin -Upper Blue Nile Basin of Ethiopia.

Dile YT, Berndtsson R, Setegn SG - PLoS ONE (2013)

Bottom Line: Climate change appears to have negligible effect on low flow conditions of the river.Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River.Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin.

View Article: PubMed Central - PubMed

Affiliation: Stockholm Environment Institute, Stockholm, Sweden ; Stockholm Resilience Center, Stockholm University, Stockholm, Sweden.

ABSTRACT
Climate change is likely to have severe effects on water availability in Ethiopia. The aim of the present study was to assess the impact of climate change on the Gilgel Abay River, Upper Blue Nile Basin. The Statistical Downscaling Tool (SDSM) was used to downscale the HadCM3 (Hadley centre Climate Model 3) Global Circulation Model (GCM) scenario data into finer scale resolution. The Soil and Water Assessment Tool (SWAT) was set up, calibrated, and validated. SDSM downscaled climate outputs were used as an input to the SWAT model. The climate projection analysis was done by dividing the period 2010-2100 into three time windows with each 30 years of data. The period 1990-2001 was taken as the baseline period against which comparison was made. Results showed that annual mean precipitation may decrease in the first 30-year period but increase in the following two 30-year periods. The decrease in mean monthly precipitation may be as much as about -30% during 2010-2040 but the increase may be more than +30% in 2070-2100. The impact of climate change may cause a decrease in mean monthly flow volume between -40% to -50% during 2010-2040 but may increase by more than the double during 2070-2100. Climate change appears to have negligible effect on low flow conditions of the river. Seasonal mean flow volume, however, may increase by more than the double and +30% to +40% for the Belg (small rainy season) and Kiremit (main rainy season) periods, respectively. Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River. The increase in flow is likely to have considerable importance for local small scale irrigation activities. Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin.

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Related in: MedlinePlus

Percentage change in monthly, seasonal, and annual precipitation for the period 2010-2099 as compared to the baseline period (1990-2001) at Dangila station.a) A2a scenario and b) B2a Scenario. Bega season = October–January, Belg season = February–May, and Kiremit season = June -September.
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pone-0079296-g004: Percentage change in monthly, seasonal, and annual precipitation for the period 2010-2099 as compared to the baseline period (1990-2001) at Dangila station.a) A2a scenario and b) B2a Scenario. Bega season = October–January, Belg season = February–May, and Kiremit season = June -September.

Mentions: Results showed a general decrease in annual mean precipitation for the 2020s and an increase for the 2050s and 2080s (Figure 4). As shown in Figure 4, in the 2020s there may be a decrease in mean monthly precipitation for all months except May, June, and July for both scenarios (A2a and B2a). For the 2020s, the A2a and B2a scenarios displayed both a mean monthly precipitation decrease by -29% and -30%, respectively. In the 2020s, mean monthly precipitation increase reached +19% for the A2a scenario and +18% for the B2a scenario. The annual mean precipitation in the 2020s may decrease by -10% and -13% for the A2a scenario and B2a scenario, respectively. For the 2050s, there may be an early occurrence and early end of precipitation as compared with the baseline period. This is reflected by an increase of mean monthly precipitation in April and a decrease in September. The overall effect in the 2050s was a small increase of annual mean precipitation by +4% for the A2a case and +2% for the B2a case. For the 2050s, an increase in mean monthly precipitation was indicated by +29% for the A2a scenario and +28% for the B2a scenario. For the 2050s, a decrease in mean monthly precipitation was indicated corresponding to -12% for the A2a scenario and -14% for the B2a scenario. For the 2080s, results indicate an increase in mean monthly precipitation during all months except in September for the A2a scenario and September and October for the B2a scenario. The increase in mean monthly precipitation was +34% for the A2a scenario and +32% for the B2a scenario. The A2a and B2a scenarios showed an increase in annual mean precipitation by +19% and +12%, respectively.


Hydrological response to climate change for Gilgel Abay River, in the Lake Tana Basin -Upper Blue Nile Basin of Ethiopia.

Dile YT, Berndtsson R, Setegn SG - PLoS ONE (2013)

Percentage change in monthly, seasonal, and annual precipitation for the period 2010-2099 as compared to the baseline period (1990-2001) at Dangila station.a) A2a scenario and b) B2a Scenario. Bega season = October–January, Belg season = February–May, and Kiremit season = June -September.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3824061&req=5

pone-0079296-g004: Percentage change in monthly, seasonal, and annual precipitation for the period 2010-2099 as compared to the baseline period (1990-2001) at Dangila station.a) A2a scenario and b) B2a Scenario. Bega season = October–January, Belg season = February–May, and Kiremit season = June -September.
Mentions: Results showed a general decrease in annual mean precipitation for the 2020s and an increase for the 2050s and 2080s (Figure 4). As shown in Figure 4, in the 2020s there may be a decrease in mean monthly precipitation for all months except May, June, and July for both scenarios (A2a and B2a). For the 2020s, the A2a and B2a scenarios displayed both a mean monthly precipitation decrease by -29% and -30%, respectively. In the 2020s, mean monthly precipitation increase reached +19% for the A2a scenario and +18% for the B2a scenario. The annual mean precipitation in the 2020s may decrease by -10% and -13% for the A2a scenario and B2a scenario, respectively. For the 2050s, there may be an early occurrence and early end of precipitation as compared with the baseline period. This is reflected by an increase of mean monthly precipitation in April and a decrease in September. The overall effect in the 2050s was a small increase of annual mean precipitation by +4% for the A2a case and +2% for the B2a case. For the 2050s, an increase in mean monthly precipitation was indicated by +29% for the A2a scenario and +28% for the B2a scenario. For the 2050s, a decrease in mean monthly precipitation was indicated corresponding to -12% for the A2a scenario and -14% for the B2a scenario. For the 2080s, results indicate an increase in mean monthly precipitation during all months except in September for the A2a scenario and September and October for the B2a scenario. The increase in mean monthly precipitation was +34% for the A2a scenario and +32% for the B2a scenario. The A2a and B2a scenarios showed an increase in annual mean precipitation by +19% and +12%, respectively.

Bottom Line: Climate change appears to have negligible effect on low flow conditions of the river.Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River.Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin.

View Article: PubMed Central - PubMed

Affiliation: Stockholm Environment Institute, Stockholm, Sweden ; Stockholm Resilience Center, Stockholm University, Stockholm, Sweden.

ABSTRACT
Climate change is likely to have severe effects on water availability in Ethiopia. The aim of the present study was to assess the impact of climate change on the Gilgel Abay River, Upper Blue Nile Basin. The Statistical Downscaling Tool (SDSM) was used to downscale the HadCM3 (Hadley centre Climate Model 3) Global Circulation Model (GCM) scenario data into finer scale resolution. The Soil and Water Assessment Tool (SWAT) was set up, calibrated, and validated. SDSM downscaled climate outputs were used as an input to the SWAT model. The climate projection analysis was done by dividing the period 2010-2100 into three time windows with each 30 years of data. The period 1990-2001 was taken as the baseline period against which comparison was made. Results showed that annual mean precipitation may decrease in the first 30-year period but increase in the following two 30-year periods. The decrease in mean monthly precipitation may be as much as about -30% during 2010-2040 but the increase may be more than +30% in 2070-2100. The impact of climate change may cause a decrease in mean monthly flow volume between -40% to -50% during 2010-2040 but may increase by more than the double during 2070-2100. Climate change appears to have negligible effect on low flow conditions of the river. Seasonal mean flow volume, however, may increase by more than the double and +30% to +40% for the Belg (small rainy season) and Kiremit (main rainy season) periods, respectively. Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River. The increase in flow is likely to have considerable importance for local small scale irrigation activities. Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin.

Show MeSH
Related in: MedlinePlus