Soil erosion by water is a serious problem in Ethiopia, contributing to diminishing crop yields and food shortages. Apart from understanding the magnitude, risk, and spatial distribution of the problem, identifying erosion hotspot areas is essential for effectively reversing the problem. This study aims to identify erosion hotspots in the Gotu watershed, in northeastern Ethiopia, using the revised universal soil loss equation (RUSLE) and incorporating local farmers' perspectives to prioritize conservation efforts. The RUSLE model reveals that 29,744.3 metric tons of soil is lost annually from the Gotu watershed, with an average loss of 65.3 to t ha(-)1 year(-)1. The main contributing factors to soil erosion in the watershed include undulating topography, loss of plant cover, and continuous cultivation. The highest soil loss rates (> 80 t ha(-)1 year(-)1) were found in the western, northern, and southern parts of the watershed, where cultivation occurs on moderate to steep slopes with sparse vegetation cover. These areas should be prioritized for conservation interventions. Farmers identified poor crop yields and damaged conservation structures as key indicators of soil erosion prevalence in the watershed. Increasing farmer's understanding of soil erosion and the importance of soil and water conservation is essential for effectively controlling soil erosion and improving food security in the area.

Due to underlying surface changes (USCs), the changes in the Taojiang River Basin's flood generation conditions could impact the flooding process in the basin. However, most studies have typically focused on either land-use changes (LUCs) or soil and water conservation measures (SWCMs) to assess the impact of the USCs on floods, which may not provide a more comprehensive understanding of the response of floods to the USCs. To investigate how the USCs have altered the floods in the Taojiang River Basin, located upstream of Poyang Lake, China, the HEC-HMS model, which incorporates the influence of the USCs into the parameter calibration, is established in this study to investigate the flood processes on an hourly scale. The flood peak and the maximum 72 h flood volume are selected as two indexes and are applied to analyze the changes in floods caused by the USCs. The 1981-2020 period is divided into three sub-periods (i.e., 1981-1992, 1993-2007, and 2008-2020) based on the conditions of the USCs. It is found that the two indexes have exhibited decreasing trends, mainly due to the USCs during 1981-2020. Benchmarked against the baseline period of 1981-1992, the two indexes decreased by 3.06% (the flood peak) and 4.00% (the maximum 72 h flood volume) during 1993-2007 and by 5.92% and 7.58% during 2008-2020. Moreover, the impacts of the LUCs and SWCMs are separated through parameter adjustments in the model, revealing that the SWCMs played a dominant role in the USCs in the Taojiang River Basin. The quantification and assessment of the impact of the USCs on floods of different magnitudes revealed that the influence decreases with increasing flood magnitude. The results of this study improve our understanding of how USCs affect the flooding process and therefore provide support for flood control management under changing environments.

Among the most widespread structures for successfully retaining water and checking erosion on the semi-arid portions of China's Loess Plateau, check dams retain silt at slower than projected rates, leading to flood control issues. Meanwhile, the shortage and the uneven distribution of time and space of water resources in semi-arid areas can easily cause droughts and floods, which seriously restricted the rapid development of the socioeconomic. However, some of the high-quality rain and flood resources accumulated in the check dams can be used to alleviate part of the water resources crisis instead of causing flood. With the goal of holistically maximizing a projected check dam array's water resource, ecosystem and socioeconomic benefits, a Check Dam Benefit Maximization Model (CDBMM) was first developed. The CDBMM was first applied to the Si Jiagou Basin, and the model showed the total costs represent 7.07% of the total and rather significant benefits. Water resources benefits accounting for 45.40% of the total benefits, indicating that the water resources benefits were substantial and should be considered as the main influencing factors in the basin's ecosystem-friendly design and construction. Use of the CDBMM in watershed planning will allow a more efficient use of water and soil resources and greatly alleviate water crises in the semi-arid area. It can further provide a reference for both check dam system planning and the system benefits analysis.