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The study's aim was to assess the impact of using water from Lake Abaya for irrigation and its impact on soil quality at Mirab Abaya, Ethiopia. Six water samples from the edge of Lake Abaya and 30 (18 irrigated and 12 rain-fed) composite soil samples from farm lands in Wajifo, Fura and Algae were collected. Analyses showed that the use of water from Lake Abaya will bring a soil salinity hazard in future. The soil analyses showed variations in space and time in the physico-chemical components in the study area. The highest salinity was reported from Algae, the closest site to the Lake. The highest soil alkalinity was reported from Wajifo, which has a long irrigation history. The irrigated soils reported higher salinity than the rain-fed soils, indicating that water from Lake Abaya can affect irrigated soil quality. In general, Lake Abaya water is not suitable for salt-sensitive crops and caution is required in using it for irrigation.

In irrigation water management, it's critical to understand the infiltration rate and its properties. The study aimed to evaluate the ability of some empirical equations and Hydrus 1D models to predict soil infiltration and evaluate the effect of initial soil moisture content on infiltration characteristics. The experiment was conducted at Arba Minch demonstration farmland using a double-ring infiltrometer, and the performance of the various infiltration models (Horton’s, Philip’s, Kostiakov, and Modified Kostiakov) and Hydrus 1D were evaluated in the study area at five different initial water contents. The results showed that the Horton and Hydrus 1D models were fitted with the observed infiltration for the soil with three initial water contents (0.13, 0.256, 0.31, 0.354, and 0.375), and the goodness of fits was evaluated by R2 and RMSE with a range between 0.9967–0.997, 0.93–0.94 and 0.0054–0.006 and 0.024, respectively. Hence, Horton and Hydrus 1D, models could be used successfully to evaluate the cumulative infiltration of soil for the study area. Therefore, in this study, the Hydrus 1D model well captured the infiltration rates at different initial soil moisture contents.