ANALYSING THE POTENTIAL IMPACT OF CLIMATE CHANGE ON SOIL EROSION A CASE STUDY OF THE NGERENGERE RIVER CATCHMENT IN TANZANIA

Abstract

The Ngerengere River watershed is identifiable by the concentration of sediment load, overgrazing, and clearing of bushes for agriculture, which reduces vegetation cover and increases erosion rates. The bulk of sediment originates from the river reaches and highland areas of Morogoro (the Uluguru Mountains), which have loose (Loam) soil and little vegetation cover. Human activities, deforestation, and climate change are visible challenges that are constantly reducing the quantity of water and the river flow from the Uluguru Mountains which act as the primary sources of water in Ruvu River which is the main supplier of water to almost 7,405,000 people in Dar es Salaam city Since land and water are the universe's precious assets and environmental healthiest, they must be properly preserved. Water resources are catalysts for economic growth, environmental sustainability, and human well-being. Effective management will be beneficial in ecosystem support, flood control, water head creation for hydropower plants, water supply, and storage for later use. Knowledge of erosion and sedimentation is one of the requirements for any appropriate planning for water resources management. Understanding how changes in climatic conditions can affect water availability, quality, and overall management of water resources is the first move that should be taken when evaluating climate change's impacts on reservoirs and the management of a watershed. Therefore, the study assesses how probable soil erosion is being affected by climate change that contributes to sedimentation in the Ngerengere River by using the SWAT model to estimate the amount of flow obtained in a watershed and sediment yield. A model and GIS analysis may provide a quantifiable and compatible method to assess soil and sediment yield erosion based on various circumstances. In this dissertation work, the analysis was done to identify how climate changes affect/contribute to soil erosion as erosion contributes to sediment deposition in the reservoir and affects other water resource structures (intake) and identify high erosion risk areas for planning and management of a watershed. Based on various conditions, modeling may provide a quantifiable and compatible method to assess soil and sediment yield erosion. A hydrological model based on soil water assessment (SWAT) compatible with the Geographic Information System (GIS) tool was used to approximate soil loss in the Ngerengere River watershed area.