Hydrological Responses to Land Use/Land Cover Changes in Koga Watershed, Upper Blue Nile, Ethiopia

Abstract

Information on land use and land cover modification and their related problems for the streamflow and sediment yield are crucial for spatial planners and stakeholders to devise suitable catchment resources management plans and strategies. This research sought to assess the changes in land use and land cover (LULC) effects on the streamflow and sediment yield of the Koga watershed. Landsat-5 TM, Landsat-7 ETM+, and Landsat-8 OLI data were used to create the land use and land cover maps. The LULC type identification analysis was performed by using ERDAS Imagine 2015. After the supervised classification, the land use and land cover maps for three distinct years (1991, 2008, and 2018) were generated, and the accuracy of the maps was reviewed. The LULC change analysis results were pointed out, as there was an appreciable LULC change in the study watershed. Agricultural land increased by 14.21% over the research period, whereas grassland decreased by 22.91%. The other LULC classes (built-up area, forest area, water body, and wetland) increased by 0.39%, 6.36%, 4.30%, and 0.46%, respectively. Contrarily, bushland decreased by 2.80%. Human activities were decisive in the significant land use alterations within the catchment. The flow rate of the river basin increased over the rainy season in the years 1991–2008 and declined in the drier months. The watershed’s sediment yield increased from 1991 to 2008 as a result of the extension of its agricultural area. Thus, the findings of this investigation demonstrated that the flow and sediment yield characteristics are changed because of the modifications within the LULC in the catchment. Some downstream and upstream parts of the area are exposed to comparatively high erosion, and the maximum amount of sediment is generated during the rainy season.

Spatio-Temporal Dynamics and Physico-Hydrological Trends in Rainfall, Runoff and Land Use in Paraíba Watershed

“…According to [31], the low percentage of Caatinga vegetation cover and the predominance of farming are correlated with animal density by municipalities, indicating the strong influence of this activity on vegetation cover reduction. [18] identified a similar pattern of land use change and expansion of farming areas, listing the main consequences of these land cover alterations as erosion and soil degradation, rural-urban migration, fragmentation of farming lands, climate change, and reduced crop yields.…”

“…In this context, the temporal evolution of land use and water dynamics in the region becomes essential, especially in the context of the river basin [14]. Some research addresses analysis of the spatio [3,6,15] and temporal dynamics of rainfall [3,5,13] and water flows [16], as well as land use and cover [11,17,18]. However, studies that integrate these processes are still limited in the Semiarid region of Brazil.…”

Detecting land use/land cover changes and forest degradation: A case study of the lower Soummam valley, northern Algeria

“…LULCC coupled with climate change has directly affected the distribution of an important tree family in the Philippines (Pang et al 2021). Land cover change can affect the risk of flooding in a peri-urban environment as in the case of the metropolitan area of Rome in Italy (Recanatesi, Petroselli 2020), as well as stream flow and sediment yield in the Koga watershed (Ayele et al 2023), and also can impact soil degradation (Ma et al 2023). Several research studies have been carried out on LULCC, among which we cite the study of Juliev et al (2019) in the Bostanlik district of Uzbekistan, which describes significant changes occurring in a major class of land use and land cover of this area and observes an increase in forest.…”