Combined effect of land use/cover types and slope gradient in sediment and nutrient losses in Chancho and Sorga sub watersheds, East Wollega Zone, Oromia, Ethiopia

Abstract

Background: The use of existing land use/cover type exerts more pressure on the natural dynamism of the watersheds and hydrology due to continued cultivation and mismanagement of land resource. The objectives of this study was to assess the combined effects of land use/cover types and slope gradient on watershed hydrology in terms of sediment and nutrient losses/transport from HRU of each land use/cover types. Integrated soil and water assessment tools (SWAT) model with Arc-GIS was used for simulation of sediment and nutrient loss by using land use/cover, soil, slope and climatic data as input. Analysis of variance (ANOVA) for mean comparison and correlation was used for data analysis. Result: Combined effects of urban land and slope gradient produced more sediment than other land use/cover types followed by cultivated land. In cultivated land as slope gradient increased values of sediment and nutrient losses also increased until it reaches to 30% slope and then declined. In Forest and grassland sediment loss increased until 15% slope then after declined, but in urban land as slope gradient increases sediment and nutrient loss are also increased. Conclusion: Cultivated land and difference in its slope gradient had more significant effect on watershed dynamics and hydrology in terms of loss of fertile top soil from upland, downstream water quality reduction and sedimentation of water structures than others land use/cover types and need to avoid steep slope and continuous cultivation and implementing integrated watershed management strategies in order to keep the natural dynamism of the watersheds.

Hydrological Components and Sediment Yield Response to Land Use Land Cover Change in The Ajora-Woybo Watershed of Omo-Gibe Basin, Ethiopia

“…The sub-basin was classified in to different categories of soil erosion categorization based on study experiences in Ethiopia (Assfaw, 2020; Chimdessa et al, 2018; Choto & Fetene, 2019; Megersa et al, 2019). It was assumed to allocate the priority stages of I–VI (Table 11).…”

Advances in characterizing and monitoring land cover/use and associated ecosystem changes using remote sensing data

“…Past investigations have shown a large variety of hydrological models used for evaluating and predicting changes in water balance (Aredo et al, 2023) and soil erosion both worldwide (Zeiger and Hubbart, 2016;Gharibdousti et al, 2019) and in Ethiopian watersheds (Miheretu and Yimer, 2018), but most of them used the Soil and Water Assessment Tool (SWAT) (see, among many others, Gessese and Yonas, 2008;Senti et al, 2014;Yesuf et al, 2015;Ebabu et al, 2019;Megersa et al, 2019;Gebretekle et al, 2022;Mariye et al, 2022;Anteneh et al, 2023).…”

Study of the Soil Seed Bank Composition in Arjo-Diga Humid Afromontane Forest under Different Land Use Types and Its Implications for the Restoration of Degraded Lands in Western Ethiopia

“…Te study area features a diverse landscape that includes plains, slopes, gentle slopes, and steep hills [38]. Tree main types of soil are present in the study area: Dystrian Nitrosols, Dystrian Gleysols, and Orthoclastic Acrisols [38]. Geologically, the study area is characterized by Precambrian rocks of high origin and migmatites [39].…”