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The Ogaden Basin is one of the largest sedimentary basins which covers an area of 350,000 km2 in Ethiopia. Since the middle of the last century, hydrocarbon exploration research has been conducted in the basin of the Calub Formation, and the Adigrat sandstone is identified to be the reservoir rocks of most Calub wells. Although enough studies have not been conducted on the reservoir rocks, to assess the potentiality of the reservoir rocks, this paper is focused on the determination of the observable porosity using petrographic methods and the estimation of the permeability and the hydrocarbon saturations using well-logging data. The used core samples were taken from Calub wells and a total of 24 core-cutting samples (Calub-4 six samples, Calub-5 six samples, Calub-7 six samples, and Calub-9 six samples) were carefully chosen, and the same number of thin sections were prepared from the core-cutting samples. The whole thin section samples collected from the laboratory were subjected to petrographic analysis and it was later interpreted. The maximum porosity and permeability observed in the reservoir Adigrat sandstone of Calub-4, Calub-5, Calub-7, and Calub-9 were 12.6% and 97.2×10−3m2 respectively while the minimum porosity and permeability observed were 3.5% and 0.1×10−3m2 respectively. The maximum porosity and permeability observed in the reservoir Calub sandstone of Calub-4, Calub-5, Calub-7, and Calub-9 were 11.3% and 18.5×10−3m2 respectively as the minimum porosity and permeability observed were 2.2% and 0.1×10−3m2 respectively. In conclusion, it can be said that the Adigrat and Calub Formations are highly hydrocarbon potential reservoirs. [ABSTRACT FROM AUTHOR]

Northwest Ethiopia (east Gojjam) has envisioned developing its Climate Resilient Green Economy strategy through the use of renewable energy sources. However, harvesting wind, solar, and geothermal energy is below the satisfactory level. Therefore, this paper aims to model and assess the potential of renewable energy to improve energy accessibility in the rural areas of northwest Ethiopia. Wind, cloud cover, temperature, and radiation data were obtained from the European Centre of Medium Range Weather Forecast (ECMWF) model. Logarithmic power-law interpolation, radiation flux, and irradiance power modeling are applied to this work. The study area model results indicated that the annual wind potential is limited for implementation. A minimum and maximum value of solar energy is found at 5.30 kWm−2 during summer and 9.75 kWm−2 during spring, respectively. The average value of the total energy flux for geothermal energy exploration is found 1500.00 Wm−2. Generally, the south and southwest parts of northwest Ethiopia have the potential to implement geothermal energy. Solar energy plantation is encouraged in the whole parts of the study area excluding Choke Mountain. Hence, a renewable energy implementation plan for energy resource management through a stakeholder engagement platform is required to convert this research into a project. [ABSTRACT FROM AUTHOR]

Climate change has been designated the most serious environmental challenge of the twenty-first century, and it will remain so in the future. To adapt to the ill effects of climate change and variability, location-specific climate analysis is essential to provide actionable evidence for informed decision making. The goal of this research was to evaluate current and future rainfall and temperature trends in central Ethiopia. We took 33 (1986–2018) years of daily rainfall and temperature data from ten stations from the National Meteorological Services Agency. The Markov chain model was used to fill in the missing values. Trends of climate variables and their extremes were analyzed using the Mann–Kendall trend test. The results showed that rainfall exhibited significant increasing trends (p < 0.05) at 80% of the stations included in the study. The start of the Kiremit season varied from June (Jun 4 at Bako) to July (Jul 1 at Shashemane) among stations; it starts June 4, June 6, and June 24 at Bako, Ambo, and Melkassa. For Asgori, the cessation date was October 1, and for Ambo, it was October 17. The average growing season varies from 95 to 136 days, and we found the shortest and longest growing seasons at Melkassa (95 days) and Ambo (136 days). The Sen's slope results showed that rainfall increased in most of the study sites from 0.2* to 12.44*, whereas it decreased from − 0.12* to − 0.21*. This has implications for agricultural practices and crop and variety choices for major crops grown in the area. To solve this problem, policymakers must work on creating awareness for the local community, which can help them withstand future climate change. [ABSTRACT FROM AUTHOR]

Seepage flow through pervious media or formations is one of the causative factors for dam failure. In order to reduce and control this problem, seepage modeling and analysis are very important. The main aim of this article is to present the comprehensive review on various modeling approaches and methods available for seepage evaluation through or beneath dam. Furthermore, an attempt is also made to assess the application and effectiveness of these techniques in dam seepage modeling and analysis. Moreover, case studies of dam seepage analysis in Ethiopia were also reviewed. For a century, various techniques have been developed that can be used to study the seepage cases of hydraulic structures including dams. Broadly, these techniques can be categorized in to continuum and discontinuum seepage modeling approaches. Continuum approach includes pore-network model, whereas discontinuum approach includes equivalent continuum, discrete fracture network, dual-porosity, and triple-porosity models. Each of these approaches may consider different causative factors and utilizes various methods for seepage analysis. The experimental, analytical, and numerical methods are commonly used in the modeling approaches based on Darcian and non-Darcian laws. The selection of appropriate modeling approaches depends on various factors and considerations including the spatial and temporal scale of flow regime, material type and properties, dam width and height, water level, availability of data, and modeler's skill. In comparison, each of these models has its own advantages and disadvantages over the other. [ABSTRACT FROM AUTHOR]

Sediment accumulation is a major factor in reducing irrigation reservoir useful life as well as reducing the reservoir capacity. Therefore, the goal of this study was to estimate the volume of sediment accumulated in the reservoir using a bathymetric survey and to assess the watershed sediment yield to reservoirs using the Modified Universal Soil Loss Equation (MUSLE) model. The bathymetric survey method involves subtracting the two-period capacities, one before dam construction and one after dam construction. On the other hand, the sediment inflow calculated by the MUSLE model over the last six years is estimated after determining the physical parameters (K, LS, C, and P factors) and runoff index (VQ and QP) from the watershed using ArcGIS 10.8 and Excel software. The bathymetric survey showed that 297,000m3 (362,340 tons) of sediment had accumulated in the reservoir over six years of operation, whereas the Modified Universal Soil Loss Equation estimated 256,262.86 tons of sediment yield at the outlet of the watershed (inflow to the reservoir). This means that the reservoir's total capacity has been reduced by 7.52 percent and 5.4 percent, respectively, over the last six years of operation, using a bathymetric survey and the Modified Universal Soil Loss Equation. According to the bathymetric survey results, the reservoir will not be functional for more than 15 years if the sediment rate remains the same as in the previous six years. Using the bathymetry method, the sedimentation rates of the dead storage and live storage zones were 31,666.67 m3/year and 48,333.33 m3/year, respectively. The watershed's sediment yield and specific sediment yield were determined using bathymetry survey results to be 61,371.95 tons/year and 45.46 tons/ha/year, respectively, whereas the sediment yield using the MUSLE model was 31.64 tons/ha/year. Since the watershed generated large amount of sediment, so to protect the filling of reservoir, the stake holders should have to apply watershed management techniques as well as should have to avoid farming near to the reservoir area. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate smallholder farmers' perceptions of climate change, adaptation strategies used to offset climate change's negative effects, and factors that influence their adaptation decisions. The respondents' survey, focus group discussion, and key informant interviews were used to gather data. Descriptive statistics and a multinomial logit model were used to examine the data. The findings indicated that smallholder farmers perceive climate change in their area. According to the findings, smallholder farmers are most likely to use adaptation measures such as crop diversification, enhanced crop variety, soil and water conservation, and altering sowing dates. The multinomial logistic regression (MNL) analysis indicated that the limitations of extension services, a lack of climate change information, a lack of financial resources, and a lack of farm experience are the key factors that influence farmers' decisions to adopt adaptation strategies. As a result, having access to extension and disseminating information regarding agricultural practices with available finance sources is a viable approach to enhance farmers' decisions to adopt strategies to reduce the impact of climate change. [ABSTRACT FROM AUTHOR]

The consensus of the scientific community across the globe showed that the planet's annual average temperature is likely to be 2 °C above pre-industrial levels of 2050 standards. It is believed that warming the globe by 2 °C due to greenhouse effect and/or climate change will result in severe rainfall amount and more frequent and intense droughts, floods, heat waves, and other extreme weather events. Gondar City of the Amhara Region will not be exceptional from this scenario. The objective of the study was to assess UHI caused by climate change in Gondar City of the Amhara Region, Ethiopia. Thirty temperature and thirty rainfall observations were taken from the Meteorological Agency. It was analyzed using Mann–Kendall trend test and homogeneity test using XLSTAT software. Analysis of the historical climate data in Gondar City revealed that there has been an increasing trend of maximum temperature and a decreasing trend in minimum temperature and a general tendency of decreasing rainfall. The results of Mann–Kendall trend test and homogeneity test also showed that the average amount of annual rainfall and maximum temperature change were significant at p < 0.05. The result also noted that there was a constant increase in maximum temperature, while high variability in rainfall from 2010 to 2020. However, there is a constant increase in rainfall from 1990 to 2020 in the study area. The increasing in temperature and the variability and increasing rainfall are evidences for the existence of climate change. The finding of Landsat temperature measurement indicates the rising temperature in Gondar City as compared to the surrounding rural areas. In conclusion, the test result and the Landsat measurement showed the presence of urban warming an indicator of UHI in the city of Gondar. [ABSTRACT FROM AUTHOR]

Crop yield prediction before harvest is a key issue in managing agricultural policies and making the best decisions for the future. Using remote sensing techniques in yield estimation studies is one of the important steps for many countries to reach their agricultural targets. However, crop yield estimates rely on labor-intensive surveys in Ethiopia. To solve this, we used Sentinel-2, crop canopy analyzer, and ground-truthing data to estimate grain yield (GY) and aboveground biomass (AGB) of two major crops, teff and finger millet, in 2020 and 2021 in Ethiopia's Aba Gerima catchment. We performed a supervised classification of October Sentinel-2 images at the tillering stage. Among vegetation indices and leaf area index (LAI) used to predict teff and finger millet GY and AGB, the enhanced vegetation index (EVI) and normalized-difference VI (NDVI) provided the best fit to the data. NDVI and EVI most influenced teff AGB (R2 = 0.87; RMSE = 0.50 ton/ha) and GY (R2 = 0.84; RMSE = 0.14 ton/ha), and NDVI most influenced finger millet AGB (R2 = 0.87; RMSE = 0.98 ton/ha) and GY (R2 = 0.87; RMSE = 0.22 ton/ha). We found a close association between GY and AGB and the satellite EVI and NDVI. This demonstrates that satellite images can be employed in yield prediction studies. Our results show that satellite and crop canopy analyzer-based monitoring can facilitate the management of teff and finger millet to achieve high yields and more sustainable food production and environmental quality in the area. The results could be reproducible under similar study catchment conditions and boost crop yield. Extrapolation of the models to other areas requires local validation. To improve crop monitoring for farmers and reduce expenses, we suggest integrating time series Sentinel-2 images along with LAI obtained from crop canopy analyzers collected during the cropping season. [ABSTRACT FROM AUTHOR]

The main aim of the study is to reveal burial history, thermal maturity and timing of petroleum generation of source rock bearing formations mainly Urandab Shale within Ogaden Basin. A study was carried out using collected core samples from wells Elkuran-1, Hilala-1, Shillabo-1, and Shillabo-2. Combinations of burial histories, geochemical analyses were used to characterize the potential source rocks and hydrocarbons generation of Lower Triassic to Upper Cretaceous Formations. Burial history showed that rapid sedimentation took place during the Jurassic-Cretaceous. Thermal modeling revealed that the obtained organic matter maturity is in the initial phase of the early oil window which is connected with subsidence due to rapid sedimentation during the Middle Jurassic to Lower Cretaceous. The amount of generated hydrocarbon is fairly good. The generated hydrocarbons are expected to be expelled from Urandab Source Rock. Overall ranking of burial-history locations in order of decreasing thermal maturity is Shilabo-1 > Hilala-1 > Elkuran-1 > Shilabo-2. Average maturation depths and hydrocarbon generative potential for Urandab Shale are as follows: Early oil at 1200 m in Elkuran-1 well, Early oil at 14,500 m and Main oil at 1750 m in Hilala-1 well, Early oil 1200 m and Main oil at 1700 m, in Shilabo-1 well and Early oil at 1100 m and Main oil at 1600 m, in Shilabo-2 well. The results indicated that gas and late oil were generated in older source intervals while good oil-prone source rocks which produce early and main oil occurred particularly in Urandab Source rock and peak petroleum generation for Urandab Shale started during the Lower Jurassic. [ABSTRACT FROM AUTHOR]

Geospatial technology is widely used to find and exploit a significant amount of groundwater in the critical zone of the Earth's crust. In fact, unconsolidated sediments are one of the main sources of aquifers in the Gelda watershed that deliver enough amount of water to the wells. The main objective of the present study has been focused on finding and assesses the most aquifer potential area for domestic, irrigation, and industrial uses. Moreover, the assimilation of geographic information system (GIS), remote sensing (RS), multicriteria decision analysis (MCDA), and analytical hierarchy process (AHP) were used to delineate the groundwater potential zone in the Gelda watershed. The methodology of this research was constructed from satellite and attribute-based geospatial data and prepared in GIS (GIS 10.4). For instance, the framework of the methodology has seven thematic factors, such as lithology, soil type, lineament density, drainage density, slope type, geomorphology, and land use/cover. Therefore, a groundwater potential zone map was developed through the use of weighted sum overlay analysis in the GIS (GIS 10.4). For most, MCDA and AHP also used to classify the groundwater potential zone, such as (1) excellent potential (37.51%), (2) good potential (42.61%), and (3) poor potential (19.87%). The accuracy and prediction of the investigation were used to validate through the spatial well data (23), receiver operating characteristics (ORC), and linear regression techniques. In general, the research predicts 86.9% of the time. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify most effective irrigation water management technique to improve yield and water productivity of onion. A combination of 3 furrow irrigation techniques, including every furrow irrigation (EFI), alternate furrow irrigation (AFI), and fixed furrow irrigation (FFI) and 2 mulch levels (grass mulch and non-mulch), was used in a factorial Randomized Complete Block Design with 3 replications. The effects of irrigation techniques and mulch on yield, yield components, water productivity, and water balance were investigated. SAS software was used for statistical analysis to investigate effects of treatments on yield and yield components. Hydrus1-D was used to simulate the soil water balance. The main and interaction effects of irrigation techniques and mulch were significant on yield, yield components, and irrigation water productivity (IWP) and on the soil water content. The maximum onion bulb yield of 29 ton/ha was recorded at EFI with mulch. The second highest bulb yield was found by AFI and FFI under mulch which was statically similar to the EFI without mulch. The minimum bulb yield of 20 ton/ha was obtained under FFI without mulch. The maximum IWP was found at AFI with mulch which was higher by 43.6% than EFI without mulch. AFI with mulch is recommended for optimum yield at maximum IWP and save water to cultivate additional land during dry season when available water is limited and land is idle. In the conditions where water availability is not limited, irrigation application should be done by EFI with mulch to maximize yield. [ABSTRACT FROM AUTHOR]