A STUDY ON THE APPLICATION OF GEOGRAPHIC INFORMATION SYSTEMS (GIS) FOR ASSESSING RAINFALL - INDUCED SOIL EROSION IN SON LA PROVINCE

Abstract

Soil erosion is a natural phenomenon that affects land across all types of terrain. This process results in the leaching of essential surface nutrients, leading to soil degradation, directly impacting crop productivity and disrupting the natural balance of the soil environment. Rainfall is the primary cause of soil erosion, accounting for the highest proportion of water-induced erosion. Son La, a mountainous province in the Northwest region of Vietnam, is characterized by steep, strongly dissected terrain and a climate with two distinct seasons, including a rainy season with high precipitation concentrated over a short period. The province has abundant soil and forest resources along with a complex river system. These features, combined with the evident impacts of climate change, make Son La's land highly susceptible to degradation, particularly rainfall-induced erosion. In this study, a map of rainfall-induced soil erosion was developed using Geographic Information System (GIS) techniques based on the Revised Universal Soil Loss Equation (RUSLE). The model incorporates five factor maps: rainfall erosivity factor (R), soil erodibility factor (K), topographic factor (LS), cover-management factor (C), and support practice factor (P). Through map overlay techniques and statistical analysis using ArcGIS software, the levels and locations of soil erosion were identified and classified into four categories: no erosion, slight erosion, moderate erosion, and severe erosion.