ISSN 1000-3665 CN 11-2202/P

    四川黄龙高山柳灌丛区钙华彩池地表水渗漏机制探究

    Exploration on the surface water leakage mechanism of travertine pools in Salix cupularis shrub area of Huanglong Scenic Spot, Sichuan Province

    • 摘要: 近年来,黄龙世界自然遗产地部分钙华景观群出现了程度不同的退化,其中地表水强渗漏及黑化、沙化等问题在高山柳灌丛密集分布区呈规模化出现,但是灌丛扩张和渗漏增强之间的关联机制尚未开展充分论证。为研究高山柳覆盖程度对钙华渗漏增强的影响,在黄龙上游映月彩池北部选取典型灌丛区彩池群,设置了4个灌丛盖度水平:无灌木(盖度<10%)、少灌木(盖度10%~30%)、多灌木(盖度30%~60%)、全灌木(盖度>60%), 实施原位入渗试验测定渗漏强度,评估灌丛区钙华孔隙结构和渗透参数变化,对比非灌丛区天然渗漏强度,进而总结高山柳灌丛影响下的钙华地表水渗漏机制。结果表明:(1)钙华彩池渗漏强度随高山柳盖度增加而增强,当盖度超过60%后,渗漏强度发生显著变异,应与大孔隙快速导流有关;(2)灌丛区因受藻类活动、植物残体分解等因素影响形成多孔隙、孔洞新生钙华,造成天然渗漏强度高于非灌丛区;(3)高山柳灌木根系活动导致钙华松散、孔隙直径增大、有效孔隙度增加、渗透系数提升,地下水渗流增强引起钙华彩池整体地表水渗漏增强;(4)高山柳根系对钙华孔隙结构改造以根劈作用为基础,并伴有根系水溶液对钙华胶结物的溶蚀作用,使钙华趋向均匀松散化,高山柳灌丛区根系和藻类活动等主要控制了地表水的渗漏增强过程。研究成果对黄龙钙华自然遗产景观演化分析和保育具有一定的参考价值。

       

      Abstract: Recently, some travertine landscape groups in Huanglong Scenic Spot have been degraded to varying degrees. Surface water leakage, blackening and desertification have occurred on a large scale in the dense distribution area of Salix cupularis shrub, which has adversely affected the core value of the Huanglong World Natural Heritage Site. The relationship between shrub expansion and leakage enhancement has not been fully understood. In this study, travertine pool group of typical shrub area was selected in the north of Yingyue Pool in the upper reaches of Huanglong, and 4 shrub cover levels were set: no shrub (coverage <10%), little shrub (coverage 10%−30%), many shrub (coverage 30%−60%), and whole shrub (coverage >60%). In-situ infiltration test was conducted to determine the leakage intensity and to evaluate the changes of travertine pore structure and permeability parameters in shrub area. With the comparison of the leakage intensities in different shrub cover level areas, the mechanism of surface water leakage of travertine under the influence of Salix cupularis scrub is summarized. The results show that (1) the leakage intensity increases with the increase of coverage. When the coverage of Salix cupularis shrub exceeds 60%, the leakage intensity changes significantly, which should be related to the rapid diversion of large pores. (2) Under the influence of algae activities and decomposition of plant residues, new travertine with more pores and holes is formed in the scrub area, resulting in higher natural leakage intensity than that in the non-scrub area. (3) The root activities of Salix cupularis shrub changes the primary travertine structure, leading to loose primary travertine and increases of pore diameter, effective porosity, and permeability coefficient. The enhanced groundwater seepage resulted in enhanced overall surface water leakage in the travertine pool. (4) The transformation of travertine pore structure by Salix cupularis roots is depended on the root cleavage. The dissolution of travertine cement by root solution leads travertine to uniform loose accumulation. The results show that the root and algal activities in Salix cupularis scrub area mainly control the process of surface water leakage enhancement. This study have basic value for the evolution analysis and conservation of Huanglong travertine natural heritage landscape.

       

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