Application of N-SPECT model and GIS for Soil erosion assessment in Sapa district, Lao Cai province

Abstract

Abstract. Sapa is a mountainous district in the western of Lao Cai province. Most of the area is mountainous terrain with steep slopes, annual precipitation of 1500 mm, plus the pressure of development activities to landforms, especially the farming operations on slope land leveling and infrastructure development, increasing the risk that the occurrence of natural disasters in this growing, including soil erosion.

The erosion of longstanding research in general and a number of studies on the Sa Pa area is largely based on the universal soil loss model of Wischmeier and Schmid (USLE) to calculate the amount of land is separated from the rib, which not only place / space of the distribution of material erosion and soil loss is real - the flow was sent. To address these limitations, the paper used N-SPECT model combined with GIS technology to assess risk of soil erosion along the stream basin system of Sa Pa. Evaluation results show that soil erosion in Sapa concentrated along the Dum, Bo Rivers. Volume erosion can be up to over 1.5 t / (ha.year), concentrated in areas with slopes greater length and poor vegetation cover, as areas in the west of San Sa Ho, Lao Chai, Su Pan, the area in the south of Ban Ho commune.

Keywords: Soil erosion, GIS, N-Spect, Sa Pa.