Author(s): Hong-Yuan Lee; Ying-Tien Lin; Yu-Jia Chiu; Jiung-Hsing Chao
Linked Author(s): Hong-Yuan Lee
Keywords: Soil erosion; Isotope 137 Cs; Mass balance; Spatial distribution; Sediment yield
Abstract: Soil erosion in the reservoir watershed, the main source of reservoir sedimentation, is a critical watershed management issue. Due to the difficulty of field investigations, empirical formulae are commonly used to estimate the soil erosion rate. However, these estimations are far from accurate. Instead, estimating soil erosion from spatial variations of 137 Cs inventory in the soil is one of the effective alternatives. 137 Cs is a manmade radioactive isotope, with a half-life of 30.2 years. It is generated mainly from either nuclear explosions or nuclear power plant leakages. Also, it can be absorbed by the soil and changes its distribution only when disturbed by a natural impact, such as rainfall. A theoretical relationship between 137 Cs inventory and soil erosion rate was established in this study. A sketch of the spatial distributions of the soil erosion rate was obtained in the Tsengwen Reservoir watershed. Using soil 137 Cs concentration to estimate soil loss is hereby proven to be a feasible soil erosion estimation approach in Taiwan. Methodologies of data sampling and analysis of this approach are given in this paper.
Year: 2004