Land Use Land Cover Dynamics on Sediment Yield Modeling of Angar Sub-Basin, Blue Nile Basin, Ethiopia

Miressa Bayisa,Dereje Adeba

doi:10.11648/j.ijepe.20211004.11

Miressa Bayisa, Dereje Adeba

Open Access

https://doi.org/10.11648/j.ijepe.20211004.11

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Abstract

The high land of Ethiopia is characterized as a region of high rates of land degradation and soil erosion, especially the Blue Nile Basin, where the eroded area is due to a significant change of land use/cover. This study aimed to estimate the sediment yield of Angar sub-basin using the Soil and Water Assessment Tool (SWAT) model interface of GIS at the outlet. The land use map of 1990, 2005, and 2018 was identified from TM, ETM+, and OLI_TIRS satellite images, and the accuracy was checked using the error matrix and Kappa statistic. The streamflow and sediment were calibrated and validated to check the model performance. The model performance has been evaluated using statistical parameters of coefficient of determination (R²) 0.75 to 0.94 for calibration & 0.77 to 0.95 for validation and Nash-Sutcliffe efficiency (NSE) 0.60 to 0.93 for calibration & 0.64 to 0.92 for validation. The annual average suspended sediment was 17.64 t/ha/yr. and the simulated annual average sediment yield was 18 t /ha/yr., 19 t/ha/yr. & 22 t/ha/yr. for land use of 1990, 2005, and 2018 respectively. The sediment severity percentage increased from land-use of 1990 to 2018 by 24.32%. due to the expansion of agricultural activities and settlement areas.

Highlights

Urbanization, deforestation, and the day-to-day activities of people settled in the Angar sub-basin resulted in a temporal and spatial change in land use land cover affected stream flow pathways and water balance [11]
Catchments are sensitive to land use induced by human activities [4] and land cover changes are predicted to have an important effect on river flows and sediment yields
The land use/cover changes in the Angar sub-basin were identified from TM, ETM+, and OLI_TIRS satellite images, and land use/cover maps of the years 1990, 2005, and 2018 were prepared and the accuracy assessments of the three maps were checked using the error matrix and Kappa statistic

Summary

Introduction

Expanding human requirements and economic activities are placing ever-increasing pressures on land resources, creating conflicts and resulting in sub-optimal use of both land and land resources. The dynamic nature of land use arising from an increasing population, expansion of the agricultural land, and climatic change. Urbanization, deforestation, and the day-to-day activities of people settled in the Angar sub-basin resulted in a temporal and spatial change in land use land cover affected stream flow pathways and water balance [11]. Land-use change is a very important issue considering global dynamics and their response to hydrologic characteristics of soil and water management in a catchment. Catchments are sensitive to land use induced by human activities [4] and land cover changes are predicted to have an important effect on river flows and sediment yields

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