Globally, land degradation causes annual fertile soil losses of around 75 billion tons. Erosion and sedimentation processes are particularly evident across the relatively young mountains of South Asia due to both natural (e.g., precipitation) and anthropogenic (e.g., road construction, agriculture/habitation on steep slopes) factors. Sediment load in the primary river basins of South Asia is there... view more
Globally, land degradation causes annual fertile soil losses of around 75 billion tons. Erosion and sedimentation processes are particularly evident across the relatively young mountains of South Asia due to both natural (e.g., precipitation) and anthropogenic (e.g., road construction, agriculture/habitation on steep slopes) factors. Sediment load in the primary river basins of South Asia is therefore very high.
Addressing high levels of erosion and sedimentation in South Asia is critical considering the high economic cost of erosion and sedimentation across multiple sectors and to the livelihoods of millions of people. In the agriculture sector, soil erosion and sedimentation lead to soil nutrient loss and reductions in crop yields and increase the need for farming inputs such as fertilizers. These processes also reduce the amount of soil available to hold water for crops and increase the need to acquire and transport water from other places. Erosion and sedimentation also affect water supply through siltation of waterways that reduces water quality, and impact water flow and recycling processes. Hydropower, a major source of strategic, clean energy in the South Asia region, is hindered by excessive sedimentation that reduces the lifespan of reservoirs by decreasing storage capacity while increasing short-term operational costs and reducing generation efficiency. Erosion, landslides, and flooding impact the roads sector, causing blockages and road washouts that cut off the flow of goods and people, in addition to requiring significant costs for repair. Climate change is projected to further exacerbate existing erosion and sedimentation challenges with the increase in intense weather patterns.
Watershed management – referring to a wide variety of practices such as slope correction using terracing, planting hedgerows and cover crops – is a form of nature-based solution that can significantly minimize the loss of soil and downstream sedimentation, with positive secondary impacts to the many sectors affected by sediment. Watershed management practices also sequester carbon. view less