华南地区水库消落带侵蚀状况与生态治理——以高州水库为例

Erosion States of Water-affected Reservoir Bank in South China and Vegetation Recovery,in Case of Gaozhou Reservoir

华南地区水库众多,消落带开阔,广泛分布有易侵蚀性红壤,在水库波浪和台风暴雨作用下,土壤侵蚀严重。以高州水库为例,波浪侵蚀使凸坡植被土壤全部流失,立坡侵蚀使凹坡不断缩陷甚至发生崩岗,径流又进一步侵蚀裸露坡面和周边沟谷。结果导致消落带水土资源环境恶劣、植被凋亡、生态功能尽失。为此,提出"桩-土-植被一体化"梯度治理方案:采用轻小群排桩护岸,截排水沟组织排水,阻隔波浪和径流侵蚀;抽取库尾淤泥回填桩后坡面形成梯级平台;种植和抚育适应周期性浸晒两栖乡土植物。方案具有适应地形、施工便捷、维护简易、清库扩容、护岸固土、改善生态和美化环境等经济实用高效的综合治理效果,预期可以在华南地区其他水库推广应用。

In South China,a plenty of reservoirs were constructed in the last century. Around many of them,especially around these medium and large reservoirs,water-affected banks are quite broad. Due to the easily erodible red soils which widely distributed in the region,under attacks of water waves,frequent heavy rainfalls and sometimes typhoons,reservoir banks were seriously eroded. For example at Gaozhou Reservoir in Guangdong Province,almost all surface soil was eroded by water waves on convex slopes which extend to the reservoir water. Due to the water waves,concave slopes were eroded vertically and collapsed toward upper hills continuously,and even finally resulted in landslides. Moreover,runoffs further erode these bare slopes and surrounding gulches. Accordingly,soil and water resources are too harsh over the reservoir banks that the vegetation is hard to survive. Their ecological functions almost completely lost. Therefore,a graded vegetation recovery scheme is proposed,named＂pile-soil-vegetation integration＂. A group of small piles are lined facing reservoir to protect bank slopes against water waves. A drainage system is deployed to prevent continuous runoff erosion. Sediments deposited at reservoir tails are dug and pumped to fill slopes behind row piles to form a set of graded platforms. Local amphibious plants,adapting South China climates and the periodic submerging and emerging conditions,are planted and well cultivated. The scheme has advantages such as well suiting to bank terrains,convenient and quick construction,easy and simple maintenance,cleaning the reservoir and increasing its capacity,protecting banks and preserving soils,improving ecological benefits and creating beautiful environments. As it is such an economical,practical,efficient and comprehensive measurement of vegetation recovery,it is expected to apply this scheme to other reservoirs in South China.