Soil loss in Koshi Basin 1990

High levels of water-induced erosion in the transboundary Himalayan river basins are contributing to substantial changes in basin hydrology and inundation. Basin-wide information on erosion dynamics is needed for conservation planning, but field-based studies are limited. This study used remote sensing (RS) data and a geographic information system (GIS) to estimate the spatial distribution of soil erosion across the entire Koshi basin. The revised universal soil loss equation (RUSLE) was used in an ArcGIS environment with rainfall erosivity, soil erodibility, slope length and steepness, cover-management, and support practice factors as primary parameters. The estimated annual erosion from the basin was around 42 million tonnes.

跨境喜马拉雅山脉流域因水力侵蚀导致的高水平侵蚀，正引发该流域水文和淹没状况的显著变化。为了 Conservation planning（保护规划）之需，亟需获取全流域的侵蚀动力学信息，然而基于现场的调查研究却颇为有限。本研究采用遥感（RS）数据和地理信息系统（GIS）对整个科西河流域的土壤侵蚀空间分布进行了估算。在 ArcGIS 环境中，本研究运用了修订后的通用土壤侵蚀方程（RUSLE），以降雨侵蚀力、土壤侵蚀性、坡长和坡度、植被覆盖与管理以及支持性措施等因素作为主要参数。据此估算，该流域每年的土壤侵蚀量约为 4200 万吨。