Land use and land cover (LULC) changes are continuous phenomena, often driven by natural and anthropogenic factors. In Ethiopia, a conversion of forest and grass lands into cultivated and urbanized lands has been reported. While such changes are known to have multidirectional impacts on river flows, erosion and sedimentation, and the socio-economic situation within a catchment, there is a lack of assessment on the scale and rate of these changes, and consequent impacts. This study quantifies the rate of LULC in the Gumara catchment (1,413 km 2 ), an important tributary to Lake Tana in northwest Ethiopia. Landsat images of three years (1986, 2001 and 2015) were processed using the supervised classification method. An extensive field survey generated over 150 ground truth points, which were used in the classification and accuracy assessment process. Then, a conceptual rainfall-runoff model (HBV) was calibrated and validated to assess the impacts of LULC changes on water balance componentsevapotranspiration, soil moisture, groundwater recharge and runoff. Additionally, the decadal means and trends of precipitation and discharge were analysed to further examine and quantify the observed changes (if any).A reasonably reliable LULC classification was achieved, with an overall accuracy of 90%. The results indicated that the catchment area under forest and grass land was about 11 and 18%, respectively, in 1986, which reduced to 5 and 10%, respectively, in 2015. In contrast, cultivated land increased from 70% in 1986 to 82% in 2015. Contrary to the expected impact of these © 2019 Manuscript version made available under CC-BY-NC-ND 4.0 license https:// creativecommons.org/licenses/by-nc-nd/4.0/ 2 LULC changes on hydrology, the HBV model, indicated only a slight change in the water balance components (±5%). Runoff and all other water balance components remained more or less stable despite considerable LULC changes. However, the uncertainties encountered in the modelling process (e.g. model structure, LULC representation) could have masked the LULC impacts on hydrology. This was supported by the significant increase in the observed discharge indicated by the statistical analysis, even in view of no substantial changes in precipitation.Therefore, LULC could cause considerable increase in discharge, which needs further testing (e.g. through physically based modelling with detailed inclusion of LULC processes).

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Article InformationSoil degradation is one of the most serious environmental problems in Ethiopia. The Ethiopian highlands have been experiencing declining soil fertility and severe soil erosion due to intensive farming on steep and fragile lands and other factors attributed to population pressure. Although different soil and water conservation structures have extensively been introduced over the past decades, sustained use of the measures was not as expected. The limited success of those efforts highlights the need to better understand the factors that influence sustainable use of structural soil and water conservation measures. This study used logistic model to investigate the major factors influencing the continued use of structural soil and water conservation measures in Farta district. Both purposive and simple random sampling techniques were applied to select sample kebeles and representative households respectively. Data collected from 162 sample households were used to estimate the logistic model. The result shows that only 47.2 percent of the respondents continually used the structural conservation measures and the remaining were not due to different determinant factors, of which perception of farmers on erosion and technology profitability was the major factor followed by institutional factors including tenure security, extension contact, access to training and membership in local organizations. Therefore, plan for intervention in soil conservation and sustainable use of measures should recognize these heterogeneous conditions and farmers' preferences.

This study examines the spatial relationship between land cover change and its drivers at varying scale in Mt. Guna. The recent land cover map was generated from Google Earth Image (2018), and the historical land cover map generated from the 1957 and 1980 aerial photos. Multi‐scale geographically weighted regression (GWR) and ordinary least square (OLS) were used to model the spatial relationship between land cover change and its drivers at varying scale. The change analysis revealed that Mt. Guna showed a dynamic land cover change between 1957 and 2018 dominated by conversions into cropland. Overall, 69% of the land cover change shows gains and losses, while 31% of the land cover of Mt. Guna showed persistence over 61 years. Furthermore, 77% of land cover was swapped and changed from its initial state. The result of modelling the spatial relationship between land cover change and its drivers showed that population density, slope gradient and clustered homestead density increases the likelihood of land cover change, while higher elevation, water source density and precipitation reduces the likelihood of land cover change. However, the spatial scale comparison indicated that the influence is stronger in large spatial scales than in small scales.