海南省松涛水库流域土壤侵蚀及控制方案

采用RS和GIS技术,基于USLE方程实现了热带地区海南岛松涛水库流域2003~2005年平均土壤侵蚀的定量模拟,通过情景分析研究了流域土壤侵蚀控制方案。结果表明:流域内潜在土壤侵蚀量约为4261万t/a,超过容许土壤流失量的60倍;在植被的保护下,现有年均土壤侵蚀量约为51.46万t/a,主要集中在退化的林地、浆纸林和橡胶林;流域平均土壤侵蚀模数略低于容许土壤流失量,但空间分布不均,部分区域侵蚀发育强烈;如对经济林、园地和耕地采取水土保持措施或恢复林草植被,能有效控制流域内土壤侵蚀,分别减少侵蚀量22.46万t和14.15万t,减少侵蚀面积98.48km²和65.90km²。

The situation and control scheme of soil erosion in Songtao Reservoir Basin of Hainan Island

As the most important water source region in Hainan Island, the Songtao Reservoir Basin has witnessed significant increases in both soil erosion and sediment in local rivers due to the exploration and utilization in recent years, so it is very important to study the situation and the control scheme of soil erosion in the basin for the protection of water environment. Taking Remote Sensed Imagery and Digital Elevation Model as basic data resource, we accomplished the quantitative simulation and analysis on the soil erosion in the Songtao Reservoir Basin based on Universal Soil Erosion Equation using Remote Sensing and Geographic Information System techniques through the wide investigation and experiments. Then we put forward a scheme for soil erosion control. The results showed that: (1) Potential soil erosion in the Songtao Reservoir Basin was about 42.6 million tons per year which was about more than 60 times of soil loss tolerance. Under the protection of vegetation, the soil erosion was about 514.6 thousand tons per year and mainly occurred to the degraded forestry, Eucalyptus forest and rubber plantation. The soil erosion in Eucalyptus forest plantation was the most severe. (2) The average soil erosion modulus in the basin was a little smaller than soil loss tolerance, but distributed unevenly. Some areas located in Xishui village were strongly eroded and reached acuity degree. (3) Vegetation was a main factor that controls soil erosion, therefore it is very essential to strengthen the protection of vegetation, especially those natural forests. According to the scene analysis, the establishment of relevant soil and water conservation facilities in plantation could help decrease soil erosion and loss coverage by 224.6 thousand tons per year and 98.48 km² respectively, while the rehabilitation of the destroyed forests and bare land could contribute to a reduction of soil losses by 65.9 km² and about 141.5 thousand tons per year. Both methods could control the soil erosion and non-point pollution effectively. From what is said above, we can draw a conclusion that the Songtao Reservoir Basin is facing serious potential soil erosion and more attention should be paid to taking specific measures to control soil erosion when this area is exploited.