Potential impact of climate change on streamflow of major Ethiopian rivers

Habimana²,

et al. 2021

Sustainability

Burundi is susceptible to future water-related disasters, but examining the influence of climate change on regional hydroclimatic features is challenging due to a lack of local data and adaptation planning. This study investigated the influence of climate change on hydroclimate-focused changes in the climatology of heavy precipitation (and streamflow) means and extremes based on the multi-model ensemble mean of earth system models in the sixth phase of the Coupled Model Intercomparison Project (CMIP). For runoff analysis, hydrologic responses to future climate conditions were simulated using the Soil and Water Assessment Tool (SWAT) model over the Ruvubu River basin, Burundi. Temperature increases by 5.6 °C, with strong robustness, under future climate conditions. The mean annual precipitation (and runoff) undergoes large seasonal variations, with weak robustness. Precipitation (and streamflow) changes between the wet and dry seasons differ in signal and magnitude. However, alterations in both the amount and frequency of precipitation reveal the intensification of the water cycle due to anthropogenic climate change. Thus, the highest variability in the maximum daily streamflow is shown in months of long wet seasons, especially in the far future (2085). Without considering the regional climate characteristics and shared socioeconomic pathway (SSP) scenarios, this behavior is expected to be enhanced in 2085 (compared with 2045) and increase the severity of extreme precipitation and flood risk. Climate change will cause alterations in the magnitude and seasonal distributions of extreme precipitation (and streamflow). These findings could be important for flood planning and mitigation measures to cope with climate change in Burundi.

Section: Introductionmentioning

confidence: 99%

Assessment of Climate Change Impacts on the Hydroclimatic Response in Burundi Based on CMIP6 ESMs

Habimana²,

et al. 2021

Sustainability

“…The 6 month analysis considered two seasons: (i) October-March and (ii) April-September. The 6 month SPI, RDI, and SDI indicated a mild to extreme drought at 40-50% of the analysed years at Holetta, Koka Dam, and Metehara, except for the SDI at Holetta, which showed a dry period at 54 2) at Koka Dam, and in 1988 (SDI = −2.8) at Metehara. The 6 month hydrological drought analysis showed the majority of the dry periods at Holetta, Koka Dam, and Metehara were mild droughts.…”

Section: The 6 Months Drought Indicesmentioning

confidence: 89%

“…Similarly, in the 2050s RCP8.5, the monthly PET increased from March to September. The periods of March-May (MAM) and June-September (JJAS) are the two main rainfall seasons as well as the main rain-fed agricultural seasons in Ethiopia [54,55]. The 2050s RCP4.5 and RCP8.5 simulations showed an increase in the monthly PET during these seasons in ARB.…”

Section: Discussionmentioning

confidence: 99%

Long-Term Variability in Potential Evapotranspiration, Water Availability and Drought under Climate Change Scenarios in the Awash River Basin, Ethiopia

2020

Understanding the hydrological processes of a watershed in response to climate change is vital to the establishment of sustainable environmental management strategies. This study aimed to evaluate the variability of potential evapotranspiration (PET) and water availability in the Awash River Basin (ARB) under different climate change scenarios and to relate these with long-term drought occurrences in the area. The PET and water availability of the ARB was estimated during the period of 1995–2009 and two future scenarios (2050s and 2070s). The representative concentration pathways (RCP4.5 and RCP8.5) simulations showed an increase in the monthly mean PET from March to August in the 2050s, and all the months in the 2070s. The study also identified a shortage of net water availability in the majority of the months investigated and the occurrence of mild to extreme drought in about 40–50% of the analysed years at the three study locations (Holetta, Koka Dam, and Metehara). The decrease in water availability and an increase in PET, combined with population growth, will aggravate the drought occurrence and food insecurity in the ARB. Therefore, integrated watershed management systems and rehabilitation of forests, as well as water bodies, should be addressed in the ARB to mitigate climate change and water shortage in the area.

“…Even though many research's have been conducted most of them has focused on trend and variability analysis of rainfall considering only the yield aspect. Even though (Tibebe et al, 2019;Gedefaw et al, 2018;Gizaw et al, 2017) has studied the hydrologic aspect still in a broader scale of Awash River basin not considering the specific condition. For instance Tibebe et al (2019) associated the streamflow at Modjo gauging station with only rainfall from Modjo station whereas there are four other station which are not considered but covering the larger area of the watershed and have immense contribution to the stream flow.…”

Section: Introductionmentioning

confidence: 99%

Hydro-climatic Variability and Trend Analysis of Modjo River Watershed, Awash River Basin of Ethiopia

2021

JEES

Climate change and variability is expected to trigger changes in temperature and precipitation series. This study aimed at assessing variability and trend of hydro-climatic variables at Modjo River watershed. Long-term climate data of 5 representative stations with in the watershed and streamflow data of Modjo gauging station (1983 -2010) were used. Rainfall variability was analyzed using Coefficient of variation (CV), Precipitation concentration index (PCI) and Standardized anomaly index (SAI). Climate trends were evaluated using Sen's slope estimator and Mann-Kendall trend test methods. The study revealed Most of the stations showed low variation in annual rainfall (CV% <20) while the main (Kiremt) and short (Belg) season rainfall exhibited CV ranging from low to high. Both annual and seasonal rainfall showed a non-significant trend at all stations for the past 30 years. However, majority of stations showed an increasing trend in annual daily average temperature ranging from 0.2 to 0.6ºC per decade. Following increases in temperature and the subsequent rise in evapotranspiration, streamflow has shown a high significant declining trend. The temporal decline in streamflow at Modjo watershed could likely affect downstream Koka dam water reserve. Thus, any watershed management strategy that can optimize water conservation for sustainable crop production and option that can improve flow to the reserve is vital.