Land degradation is a series problem in Ethiopia highlands, particular in abbay basin reflected in the form of soil erosion and soil fertility decline from time to time. Beshilo catchment is one of the Abbay basin tributary, which covers 5,700 km2; this shows that the problem of the catchment is significant effect in Abbay basin development. In this study the impact of Land use/ Land cover change on annual outflow contribution of Beshilo Catchment is evaluated, distributed physically based hydrological model known as soil and water assessment tool (SWAT) model was used this study. Changes were analyzed and characterized impacts on surface runoff were evaluated. The model was calibrated and validated over the gauged upper reaches of catchments of Gummara River. The model was calibrated for the period from 1999–2008 and validated for the period from 2009–2014. The performance of the model was evaluated on the basis of performance rating criteria, coefficient of determination, Nash & Sutcliff efficiency. The overall performance of the models gives good result. For this study the land use land cover change scenario, were developed using its change. From the land cover change analysis results it was found that there has been a substantial decline of forest lands, shrub lands, grass lands and expansion of agricultural land. The SWAT modeling shows the result indicated that the mean annual stream flow were increase by 7.4% with 2004 LULC from 1996 LULC and increased by 6.8% with 2013 LULC from 1996 LULC.

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Scarcity of freshwater resource threatens sustainable agricultural production in arid and semi-arid regions of Ethiopia. Therefore improved irrigation technologies needed to be developed for water saving and increase productivity per unit of water. Deficit irrigation is a recent innovative approach of water-saving method that reduces irrigation amounts and maximizes water productivity. The field experiment on tomato crop was undertaken at Arba Minch, South Nations, Nationalities and Peoples Region of Ethiopia. The objectives of the study were assessing the impact of deficit irrigation at different growth stages on the phenology, crop yield, and water productivity, and identifying the sensitive crop growth stage of tomato to waters stress. The result of the study shows a highly significant difference (P ≤ 0.05) among treatments for phenology, yield and yield components, and Water use efficiency. The highest fruit yield (64.65ton/ha) was obtained from the control treatment which was not significantly different from treatment with 65%ETc applied at stage I (63.28 tons/ha). The highest crop water use efficiency 18.78kg/m3 and gross benefit 646073.04 Birr/ha were gained from treatment with the application of 65% of ETc during the vegetative stage. On the other hand, the crop yield response factor shows that the flowering and fruit development stage was highly sensitive to water stress. Whereas, the sensitivity of the vegetative growth stage to water stress was minimum. This shows that applying deficit irrigation at the flowering and fruit development stage results in a potential yield reduction and deficit irrigation at this stage is not recommended. The application of 65% ETc deficit irrigation during the vegetative stage can solve the water shortage problem without significant yield reduction.

Surface water pollution is a global problem and has been evident for a long period of time. Hence, the aim of the study was to evaluate the hydro-geochemical characteristics of Selamko farm reservoir water quality and its suitability for multipurpose uses using GIS-based water quality indices. The water sampling sites and parameters were selected systematically based on the land use, land cover, and anthropogenic activities around Selamko reservoir watershed in Debre Tabor, Ethiopia. Water samples were collected from 11 sampling stations from July 2019 to March 2020 using the composite sampling method and examined using standard procedures. The suitability of the reservoir's water quality for multipurpose use was investigated using drinking and irrigation water quality indices, and other tools. The spatial distribution maps of water quality parameters were prepared using the kriging method in ArcGIS 10.5. The results of the geospatial analysis indicated that the reservoir water quality parameters had spatial variation, which was caused by industrial and household wastewater inflow across the reservoir's watershed. Based on WHO and ES standards, the computed drinking water quality index results revealed that 81.81% and 18.18% of the reservoir's water quality fall into the poor to very poor classes, which indicates that the water in the reservoir is not fit for drinking. However, a Wilcox diagram, irrigation indices, and USEPA regulations revealed that the reservoir water quality is found to be safe and suitable for irrigation, fishing, and livestock purposes. The study concluded that Selamko reservoir's water quality is suitable for irrigation, fishing, and livestock watering with proper management accordingly.