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Evaluating the flood and drought hazards provides vital information for sustainable water resources management, particularly in semi-arid, water-deficit environments. Most prior studies were limited in exploring the flood and drought hazards, which are important for early warning systems and preparedness. This study characterized the hydrological extreme hazards on the Gereb-Geba reservoir, namely the Suluh, Genfel, and Agula rivers. Flood frequency analysis was performed using the fitted flood frequency distribution in MATLAB. The 2D hydrodynamic model HEC-RAS was implemented to produce a flood-inundation map. Meteorological, agricultural, and hydrological droughts were analyzed using the Standardized Precipitation Index (SPI), Vegetation Condition Index (VCI), and Streamflow Drought Index (SDI), respectively. Using the Generalized Extreme Value (GEV), the estimated flood magnitude showed an increasing tendency in all the rivers across all the return periods (2-, 5-, 10-, 20-, 50-, and 100-years). The reservoir inundated an area of 12.8 km2 at an elevation of 1830 m.a.s.l. with a water depth of 80 m at the outlet. Suluh experienced more severe to extreme hydrological drought episodes than the Agula and Genfel rivers. Severe to extreme meteorological droughts were also observed in the respective catchments. Moreover, severe agricultural drought prevalence was also detected across all the river catchments. This study provides vital and comprehensive flood and drought information for water resources planning, management, and development.

Abstract Human activities and climate change pose a significant threat to the dry Afromontane forests in Ethiopia, which are essential for millions of people both economically and ecologically. In Ethiopia, trees are planted elsewhere even if they are not likely to be well suited to the area. This study aims to identify the suitable habitat for the most exploited Juniperus procera (J. procera) and Olea europaea (O. europaea) tree species in northern Ethiopia. As inputs, least correlated temperature, moisture, soil, and topographic variables were selected through a stepwise procedure. The study evaluated five individual and ensemble models using the area under the curve (AUC) and true skill statistic (TSS) values. The ensemble model outperformed with mean AUC of 0.95 and TSS of 0.78 for J. procera, while securing the second position for O. europaea with an AUC of 0.88 and TSS of 0.71. Climatic factors emerged as the most influential, followed by soil and topography. Suitable areas for both species were found when Isothermality (Bio3) values range from 52% to 62%, temperature seasonality (Bio4) of 16–29°C. Moreover, well drained soils with soil texture not heavier than sandy clay, and soil organic carbon ranging from 5 to 42 g kg−1 were found suitable. The optimal suitable altitude for J. procera and O. europaea was determined to be 2200–2600 and 2100–2500 m.a.s.l., respectively. The suitable areas for J. procera and O. europaea were estimated to be 3130 and 3946 km2, respectively. Furthermore, potential plantation areas were identified beyond Desa'a and Hugumbirda Grat‐Kahsu protected forests, covering 2721 km2 (86.9%) for J. procera and 3576 km2 (90.6%) for O. europaea. These findings hold significance for the conservation and sustainable management of these valuable tree species in northern Ethiopia. We recommend implementing a similar approach for other locally restricted dry Afromontane tree species with wider potential distribution.

Abstract Background Below-normal availability of water for a considerable period of time induces occurrence of drought. This paper investigates the Spatio-temporal characteristics of meteorological drought under changing climate. The climate change was analyzed using delta based statistical downscaling approach of RCP 4.5 and RCP 8.5 in R software packages. The meteorological drought was assessed using the Reconnaissance Drought Index (RDI). Results The result of climate change projections showed that the average annual minimum temperature will be increased by about 0.8–2.9 °C. The mean annual maximum temperature will be also increased by 0.9–3.75 °C. The rainfall projection generally showed an increasing trend, it exhibited an average annual increase of 3.5–13.4 % over the study area. The projected drought events reached its maximum severity indicated extreme drought in the years 2043, 2044, 2073, and 2074. The RDI value shows drought will occurred after 1–6 and 2–7 years under RCP 4.5 and RCP 8.5 emission scenarios respectively over the study area. Almost more than 72 % of the current and future spatial coverage of drought in the study area will be affected by extreme drought, 22.3 % severely and 5.57 % also moderate drought. Conclusions Therefore, the study helps to provide useful information for policy decision makers to implement different adaptation and mitigation measures of drought in the region.

Purpose: We compared the distribution of the HLA-B27 allele among Ethiopian patients with acute anterior uveitis (AAU) and controls without that disease., Methods: The clinical features of patients were collected from their medical records. HLA-B27 genotyping was performed for 64 patients, with AAU using the real-time polymerase chain reaction (RT-PCR), and the results were compared to those from a panel of 192 healthy, unrelated volunteer control participants (refraction patients and volunteers) free of signs of anterior uveitis. Other outcomes were assessed comparing HLA-B27 positive vs. negative patients., Results: The histocompatibility antigen HLA-B27 was identified in 6 out of 64 (9.4%) AAU patients, compared with 1.0% in controls (Odds Ratio = 9.8, 95% CI (1.93, 50.01)). Sub-group analysis of the cases revealed that patients with HLA-B27 positivity had a higher incidence of ocular hypertension (Odds Ratio = 5.93, 95% CI (1.29, 27.2))., Conclusion: The antigen HLA-B27 was represented ~10-fold more frequently in the patient group than in the control group. HLA-B27 allele distribution in both cases and controls is lower than in reports from Caucasian and Asian populations, but similar to South Africa.