The Runoff Characteristics and Sediment Yield on Devastated Granite Mountain in Jiangxi, China

Abstract

Over the past three years, the authors observed the rainfall, runoff and sediment yield of devastated small forest basins located in the Jianxi province, in the southern part of China. The experimental basins are in a hilly mountainous area on weathered granite ground. The area has many bare slopes and ruined forests. The devastation resulted from the moving of ground-plants, and removal of fallen leaves for use as fuel. The authors analyzed the observed data consisting primarily of rainfall, runoff, and sediment yield data. Through the observations, the authors noted that, (1) Precipitation in this area is concentrated during the rainy season from March to August, the most rainfall is considered to be discharged by overland flow. (2) In the first half of the rainy season, there is much unstable sediment on the surface due mainly to “frost heaving”. And the most sediment is discharged by overland flow, which is indicated by the ratio of the peak discharge to the peak rainfall intensity. During this season, the ratio effects the sediment discharge, (3) In the latter half of the rainy season, there is less unstable sediment yield on the surface and the discharge depends on the maximum rainfall intensity.