岩溶水柜集流坡面的径流模式和调控建议

Runoff pattern and adjusting measure of the karst slope for tanks

  • 摘要: 作为南方岩溶地区水柜水源的坡面径流,其形成和动态变化缺少精确且详细的解析。选择桂林丫吉试验场峰丛洼地的一个表层岩溶泉为对象,通过1个水文年多指标的监测,获得不同降雨条件下坡面径流的水文和水化学动态过程,以水文分析和水化学示踪解析径流水文特征、产流条件和水源组成。结果表明:坡面径流的水文过程季节性变化对比强烈,低水位总时长占全年的一半,连续时长超过3个月,全年连续断流有40多天,显示坡面径流水源不稳定,具有调控的必要性;受控于溶蚀作用的水化学动态展示了来自于多种界面的径流汇合过程;电导率等指标的波动共同指向降雨事件中形成于裸岩区的石面流发挥先锋作用。依据集流场的下垫面结构从3个方向提出调控建议:减少裸岩区径流渗漏;改善表层岩溶带通透性;揭露覆盖区隐伏径流。这些措施将有助于增加水柜蓄水量,提高径流利用效率。

     

    Abstract: The formation and dynamics of slope runoff as karst aquifer recharge process are rarely described specially for the karst area of South China. A spring which discharge epikarst in Yaji experimental site was selected as the research point. The hydrological and hydrochemical dynamic process under different precipitation conditions were obtained through multi-parameter monitoring for a hydrological year. Understanding the dynamic characteristics of runoff formation conditions as well as water source composition of slope flow were formed using hydrological and hydrochemical analyzes. According research there are strong seasonal changes which reflected on the hydrological processes for slope runoff. The total duration of low water level is half of the year, the continuous duration is more than 3 months, and more than 40 days are continuous dry-up throughout one hydrological period. All this indicates instability and variability in slope runoff, and it is necessary to apply certain measures in regulating this process. The hydrochemical dynamics controlled by carbonate dissolution show the merging of runoff from different geological formation. The oscillation of electrical conductivity as well as other indicators show that the runoff formed in bare rock surface plays vary important role. According to the geological structure of slope area regulation through three approaches is proposed: reducing runoff leakage in bare rock area; improving permeability of the epikarst zone; exploring karst conduits in dolines. These measures will help to increase the storage capacity of water tank and improve the utilization efficiency of runoff.

     

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