Yonas Gebresilasie Hagos

Erosion of soil refers to the process of detaching and transporting topsoil from the land surface by natural forces such as water, wind, and other factors. As a result of this process, soil fertility is lost, water bodies’ depth is reduced, water turbidity rises, and flood hazard problems, etc. Using a numerical model of erosion rates and erosion risks in the Jejebe watershed of the Baro Akobo basin in western Ethiopia, this study mapped erosion risks to prioritize conservation measures. In this study, the Revised Universal Soil Loss Equation (RUSLE) model was used, which was adapted to Ethiopian conditions. To estimate soil loss with RUSLE, the rainfall erosivity (R) factor was generated by interpolating rainfall data, the soil erodibility (K) factor was derived from the soil map, the topography (LS) factor was determined from the digital elevation model (DEM), cover and management (C) factor derived from the land use/cover data, and conservation practices (P) factor generated from digital elevation model (DEM) and land use/cover data were integrated with remote sensing data and the GIS 10.5 environment. The findings indicated that the watershed annual soil loss varies from nearly 0 on a gentle slope of forest lands to 265.8 t ha⁻¹ year⁻¹ in the very steep slope upper part of the watershed, with a mean annual soil loss of 36.2 t ha⁻¹ year⁻¹. The total annual soil loss in the watershed is estimated to be around 919,886.5 tons per year. To minimize the amount of soil erosion in the watershed that had been most severely affected, we identified eight conservation strategies that could be implemented. These strategies were based on the participatory watershed development (PWD) principles established by the Ethiopian government and the severity of the erosion in the watershed. The study’s findings showed that a GIS-based RUSLE soil erosion assessment model can provide a realistic prediction of the amount of soil loss that will occur in the watershed. This tool can also help identify the priority areas for implementing effective erosion control measures.

Land suitability assessment for irrigation is critical to inform as well as manage current and future irrigated agriculture production systems. Land suitability analysis determines whether a given land area could potentially be used for specific crop production. The objective of this study was to identify the availability of suitable land for surface irrigation systems for the production of millet, sorghum, sugarcane, and wheat production in the Lower Omo Gibe plain, Southern Ethiopia. Land suitability analysis was performed by a parametric method using factors such as soil texture, effective soil depth, Calcium Carbonate (CaCO₃), soil electrical conductivity (ECe), drainage class, and slope. Five land suitability classes were identified that include highly suitable (S1), moderately suitable (S2), marginally suitable (S3), currently not suitable (N1), and permanently not suitable (N2). Results showed that 6.6, 7.5, 6.6, and 6.6% of the study area mostly located in the western part of the basin, were highly suitable (S1) for irrigated millets, sorghum, sugarcane, and wheat crops production, respectively. However, the mountainous areas in the central part of the basin were classified as N2 due to the steep slope and shallow soil depth. Overall, the results of the study revealed that the use of various suitability analysis techniques could assist in identifying suitable land for irrigated agriculture.

The erosion of soil is one of the most difficult and ongoing problems caused by deforestation, improper cultivation, uncontrolled grazing, and other anthropogenic activities. As a result, assessing the level and quantity of soil erosion is essential for agricultural productivity and natural resource management. Thus, the goal of this study was to quantify soil loss rates and identify hotspot locations in the Tashat watershed, Abay basin, Ethiopia. Thematic factor maps, comprising rainfall erosivity factor (R), soil erodibility factor (K), topography factor (LS), cover and management factor (C), and conservation practices factor (P), were integrated using remote sensing data and the GIS 10.3.1 environment to estimate soil loss using RUSLE. The findings indicated that the watershed annual soil loss varies from none in the lower part to 3970.6 t ha⁻¹ year⁻¹ in the middle, with a mean annual soil loss of 64.2 t ha⁻¹ year⁻¹. The total estimated annual soil loss was 61,885,742.9 tons from the total watershed area of 48,348.4 ha. The majority of these soil erosion-affected places are geographically located in the watershed middle steepest slope portion, where Cambic Arenosols with higher soil erodibility character than other soil types in the research area predominate. Thus, sustainable soil and water conservation techniques should be implemented in the steepest middle section of the study area by respecting and acknowledging watershed logic, people, and watershed potentials.

Floods have destroyed people’s lives as well as social and environmental assets. Flooding is becoming more severe and frequent as a result of climate change and an increase in human-induced land-use changes, which puts pressure on river channels and causes changes in river morphology. The study was aimed to assess flood danger and map inundation areas in Ethiopia’s Teji watershed, which is prone to flooding. The basic flood-producing factors in this study were derived from soil, slope, elevation, drainage-density and land use land cover data. The opinions of public institutions and expert decisions were gathered to determine the weight of the factors in the analytic hierarchy process. The collected data were processed using the ArcGIS environment and the analytic hierarchy method to produce a flood danger map. According to the findings of this study, approximately 43.28 and 13.09% of the area were vulnerable to high and very high flood risk zones, respectively. As a result, flood prediction, early warning and management practices could be implemented on a regular and sustainable basis.

Irrigation development necessitates suitable lands for higher yield production and the development of long-term irrigation systems. The purpose of this research was to identify appropriate irrigation lands for irrigation in the Minch Yekest watershed in West Amhara, Ethiopia. Geospatial and multi-criteria decision-making techniques were used in this study. For land suitability analysis for surface irrigation, slope, land use, altitude, distance from the water source, soil characteristics, and available water storage capacity parameters were used. To find the best location for surface irrigation, the values were weighted and combined using the weighted overlay tool. The irrigation land suitability of each physical land parameter was classified into four suitability classes (S1, S2, S3, and N) based on the Food and Agricultural Organization guideline. According to the findings, 63% of the watershed area is highly suitable, 6.25% is moderately suitable, 28.69% is marginally suitable, and 2.06% is not suitable for the aforementioned purposes. The methodological approach and study findings could help policymakers make better decisions when developing irrigation projects in Ethiopia.

Ethiopia is Africa's second-most populous country, after Nigeria, and is primarily a farming community with low productivity that is heavily reliant on rain-fed agriculture. Water scarcity, global warming, and rising population all necessitate more effective water conservation methods. As a result, the demand for dams is increasing dramatically in order to provide the community with safe drinking water, electricity, and irrigation to ensure food security. The goal of this study was to use remote sensing and geographic information system (GIS) techniques in conjunction with the dam suitability stream model and multi-criteria decision analysis to identify potential sites for multi-purpose dam construction. The study used six influencing factors to find suitable dam sites, with the model's suitability stream and overall suitability output maps proposed and evaluated as a result. Based on the topography and land use, the results showed that three proposed dam sites in the upper part of the watershed are likely preferable for irrigation, fishery, and clean drinking water supply. The three proposed dam sites in the watershed's lower reaches, however, are better suited to hydropower generation. In addition, remote sensing and GIS are useful in dam/reservoir site selection because they allow decision-makers to create, manipulate, and manage relevant thematic layers.

Background:Zariema watershed located in the Tekeze basin Northern highlands of Ethiopia has been a subject to serious problem of soil erosion. Soil degradation due to soil erosion is one of the key environmental and socioeconomic case which threats soil nutrient depletion and food security in northern Ethiopian highlands. This study was conducted to estimate the soil loss rate and identify hotspot areas using RUSLE model in the Zariema watershed, Tekeze basin, Ethiopia.Methods:The rainfall – runoff erosivity(R) factor was determined from mean annual rainfall, soil erodibility(K) factor from soil map, Topographic factor (Ls) were generated from DEM, Crop management factor (C) and Conservation support practice factor(P) obtained from land use/land cover map. Finally, the factors were integrated with Arc GIS 10.3 tools to estimate soil loss rates and landscape vulnerability to soil erosion of the study watershed. Results:Annual Soil losses rates were estimated to be between 0 ton ha^-1 year^-1 in plain areas and 989 ton ha^-1 year^-1 in steep slope areas of the study watershed. The total annual soil loss from the entire watershed area of 2239.33Sq. Km was about 3,603,895.23 tons. About 31.41% of the study areas were affected through the soil loss hazard which is above acceptable soil loss rate 11 ton ha^-1 year^-1. The spatial hazard classification rate was 68.59% of the watershed area categorized as slight (0 – 11 ton ha^-1 year^-1), 8.03% moderate (12 – 18 ton ha^-1 year^-1), 7.64% high (19 – 30 ton ha^-1 year^-1), 6.65% very high (31 – 50 ton ha^-1 year^-1) and 9.09% severe (>51 ton ha^-1 year^-1). Conclusion:As a result, In the cultivation land around steep slope the soil loss rate was in sever condition. To mitigate the severity of the soil erosion in the identified prone area which accounts for about 31.41% of the total watershed area immediate action of soil and water conservation required.