【作者】 李林立；

【导师】 袁道先；

【作者基本信息】 西南大学 ， 自然地理学， 2009， 博士

【摘要】 西南岩溶区是一种受地质背景制约的脆弱生态环境。受地质环境的特殊性,大气降雨很快渗入地下,造成水土资源空间配置严重失调,以致土壤贫瘠,水土流失严重,地表水资源匮乏。缺水干旱已成为岩溶石山区长期处于贫困和落后的主要原因之一。表层岩溶带地下水作为岩溶水有效开发利用资源的一部分,己成为岩溶石山地区居民用水的重要水源之一和石漠化治理的希望。表层岩溶带与生态环境一起对岩溶水文系统进行调蓄,构成岩溶地区特殊的上部以表层岩溶水系统为主体与下部以地下河管道为主体的二元水文地质结构。生态环境中植被土壤明显地影响表层岩溶水的循环特征。野外研究已经发现具有不同生态环境下的表层岩溶泉水文过程差异显著。石漠化环境条件下,表层岩溶泉水暴涨、暴落,雨季造成洪涝,旱季断流无水;而森林茂密的原始森林,表层岩溶泉水常流不断,动态相对比较稳定,因此,通过生态环境对表层岩溶水调蓄功能的影响研究,认识和把握生态环境调蓄表层岩溶水的功能和机制,这对于防治岩溶石山地区的石漠化和通过生态恢复来开发表层岩溶水资源具有非常重要的意义,同时也为建立适宜岩溶区的SVAT模型奠定基础。本文在重庆市南川区选择金佛山水房泉、柏树弯泉、兰花沟泉和向家院子泉四种不同生态环境下的表层岩溶泉域为研究对象,其中金佛山水房泉域主要土地覆被类型为亚高山草甸,柏树弯泉域主要土地覆被类型为马尾松林,兰花沟泉域主要土地覆被类型为玉米,而向家院子泉域主要土地覆被类型为次生樟树林。分别通过表层岩溶泉流量衰减曲线,降雨过程中土壤含水量、土壤水分增量以及降雨、穿透雨、土壤水和表层岩溶泉的水化学性质的对比分析,从不同生态环境下表层岩溶含水层介质特点、土壤调蓄功能和植被土壤对表层岩溶含水系统水质的影响三个方面,研究生态环境对表层岩溶水调蓄功能的影响。首先,通过对表层岩溶泉流量衰减曲线的分析,分别计算表层岩溶泉衰减的第一亚动态、第二亚动态和第三亚动态衰减系数和占水比例。研究发现:（1）良好的生态环境有利于表层岩溶含水层裂隙级空间的发育,促使裂隙级岩溶水衰减速度变小,衰减系数变小。（2）生态环境对表层岩溶含水层孔隙级岩溶水衰减系数影响较小,其主要由岩层孔隙度决定。（3）厚层枯枝落叶可能延缓岩溶管道水的衰减,使管道水衰减系数变小,降级,成为裂隙级岩溶水衰减系数。（4）良好生态环境下发育的表层岩溶带调蓄能力强。从占水比例比较,裂隙级岩溶水与孔隙级岩溶水的总量,也即最有意义的调蓄水量,都占90%以上。其次,通过对四种不同生态环境下表层岩溶泉域土壤水、大气降雨和表层岩溶泉流量的监测分析,采用连续等效介质模型,计算土壤水分增量及其对降雨的响应和表层岩溶泉流量的影响。研究发现:（1）土壤具有明显的调蓄功能。雨前,土壤水分增量为负,随着降雨进行,土壤水分增量开始增加,但都不立刻出现峰值,相比降雨有一定的滞后,同时土壤水分增量曲线起峰一般也早于泉水流量曲线。由于土壤的调蓄,降水对表层岩溶泉的补给存在明显滞后效应。（2）土壤调蓄功能主要集中在土壤的中上层,而非整个土壤剖面。（3）良好生态环境下土壤调蓄能力强。根据计算,柏树弯泉域、水房泉泉域、向家院子泉域和兰花沟泉域的土壤调蓄系数分别为90.74%、72.65%、52.12%和33.33%。最后在四个表层岩溶泉域收集大气降雨、穿透雨、土壤水和表层岩溶水,从大气降雨到表层岩溶含水系统出流为止,分不同层次对水质进行分析,研究HCO₃^-、Cl^-、Ca²⁺、Mg²⁺、Na⁺、K⁺、SO₄^2-在大气降雨-植被-土壤-表层岩溶泉各个不同层次的迁移状况和表层岩溶泉水化学对大气降雨的响应。研究发现:（1）生态环境对水的pH值有较大的调节作用,植被有酸化雨水的功效,而土壤则缓解环境酸化。从降雨到穿透雨,水的pH值降低,呈弱酸性。从穿透雨到土壤水,水的pH值逐步升高,呈弱碱性。（2）植被土壤能改变水的化学特征,促进元素迁移,增加表层岩溶泉水化学物质总量。从降水到表层岩溶水,各种离子浓度都升高,尤其是HCO₃^-,Ca²⁺,Mg²⁺浓度,表层岩溶水分别约为降水的25、14和70倍。（3）农业生态环境能促使土壤NO₃^-、SO₄^2-大量释放。兰花沟表层岩溶水NO₃^-与SO₄^2-的浓度与其上覆的土壤水相比,增幅分别为60.4%,60.7%,而向家院子泉只有5.5%和37%。（4）降雨条件下,生态环境对表层岩溶水化学变化具有明显的调蓄功能。表层岩溶水水温、pH、Ec峰值对应降雨峰值都有一定程度的滞后。综上所述,生态环境对表层岩溶水的调蓄具有明显的影响,它不仅影响表层岩溶水资源的量,也影响着表层岩溶水的质。良好的生态环境有利于对表层岩溶水的调蓄。因此在进行表层岩溶泉的恢复和石漠化治理过程中,必须加强水土保持林的建设,以促进岩溶石山生态环境向良性转变。更多还原

【Abstract】 Karst area in southwest of China is fragile environment. The rainwater fast infiltrates into underground for special geological background. It could lead that soil resources are not coherent with water resources in space distribution. So there are thin soil, seriously water loss and soil erosion and short surface water in these karst areas. Those local people lives much poor. One of the main matters of poverty is shortage of water and dry in karst mountainous district without soil. As a part of efficient exploitation karst water, the Epikarst water has become an important wellspring for those people living in mountainous area. Of course it could also be used to bring the karst stone desertification under control. The water of epikarst aquifer in karst hydrological system could be adjusted by epikarst zone and ecological environment. So the special dual hydrogeology structure was formed for karst aciton. It may be made of up and down parts. The upper is mainly consisting of the epikarst water. The lower is mainly made of underground rivers. Obviously soil and vegetation affect the water cycle of epikarst. There is distinct difference for hydrological course of epikarst spring under different ecological environment through abundant wild research. In desertification area the discharge of Epikarst spring increased and declined rapidly. There was flood in rain season while drought in arid season. But in a dense and primitive forest the discharge of epikarst did not be cut off ever and keep a stable flux. Thus the effects of ecological environment on regulated function of epikarst water should be known and holded throuth a lot of research. Furthermore to master the function and mechanism is great important for preventing and harnessing the desertification. It also includes exploitation epikarst water through ecological recovery. Homochronously it can also be built the base for SVAT（soil-vegetation-atmosphere transfer） model in karst area.The thesis aimed at four epikarst spring watersheds respectively formed under four kinds of different ecological environments in Nanchuan city of Chongqing, China. They are respectively Shuifang spring watershed in Mt.jinfo, Boshuwan spring watershed in Dapuzi village, Lanhuagou spring watershed and Xiangjiayuanzi Spring watershed in Nanping town. The main vegetation is subalpine meadow in Shuifang spring watershed, Pinus massoniana in Boshuwan spring watershed, corn in Lanhuagou spring watershed and camphor in Xiangjiayuanzi spring watershed. In the study, firstly, characters of epikarst aquifer were discovered through the recession curve of epikarst spring. Secondly, regulating function of soil could be known on the basis of the seriate same medium model through monitoring soil water content in rain. Thirdly, the effects of vegetaion-soil on the quality of epikarst water be knowed through the analysis of water quality on rainfall, throughfall, soil water and epikarst spring. In the end effects of ecological environment on regulated function of epikarst water were mastered on the base of the front analysis.Firstly recession process of epikarst spring can be divided into three stages. Recession coefficient of epikarst spring and the ratios of conduit water, fissure water and miscibility gap water in epikarst aquifer could be respectively calculated in the stage I, stage II and Stage III according to the analysis of recession curve of epikarst spring flux. The conclusions were as follows: （1） the amount of fissure in epikarst aquifer could more easily increase under good ecological environment. Recession Velocity of fissure water could become smaller and recession coefficient could become smaller too. （2） The effects of ecological environment on recession coefficient of miscibility gap water in epikarst aquifer were not obviously. The recession coefficient of miscibility gap water was mainly controlled by porosity of carbonates. （3） Heaver litter layer might slow down the recession velocity of conduit water. Its recession coefficient became small and conduit water might be recognized as fissure water in calculation. （4） Regulation function of epikarst was remarkable under good ecological environment. The total ratio of fissure water and miscibility gap water in the whole water in epikarst aquifer, the more important water, were all respectively above 90% in Shuifang spring watershed, Boshuwan spring watershed and Xiangjiayuanzi spring watershed.Secondly the increment of soil water could be calculated on the basis of the seriate same medium model through monitoring soil water content, rain and flux of epikarst spring. The characters of increment of soil water varied with rain could be analyzed. Correlation between the increment of soil water and flux of epikarst spring was gripped too. The conclusions were as follows: （1） soil was obviously of regulating epikarst water. Before it was raining the increment of soil water was negative. When it rained the increment of soil water began to increase. But it could not arrive at the maximum value right now. The maximum value of increment of soil water lagged behind the maximum value of rain. Synchronously it was earlier for the increment of soil water than the increment of epikarst spring flux. Because of regulation of soil the maximum of epikarst spring flux lagged behind the maximum of rain. （2） Storage capacity of soil was focused on the middle-up soil layers, not the whole soil layer. （3） Soil was obviously of regulating function in good ecological environment. According to obtained value the coefficient of soil regulation were respectively 90.74%, 72.65%. 52.13% and 33.33% in Boshuwan spring watershed and Shuifangquan spring and Xiangjiayuanzi spring watershed and Lanhuagou spring watershed.In the end on the basis of analysis of HCO₃^-、Cl^-、Ca²⁺、Mg²⁺、Na⁺、K⁺、SO₄^2- ions concentration in in rainwater, throughfall, soil water and epikarst water, Characters of these varied ions concentration were respectively obtained in four spring watersheds. Furthermore chemical characters of epikarst spring varied with rain could be analyzed. The conclusions were as follows: （1） ecological environment was relatively of regulating pH value of water. Based on the analysis of the pH value of rainwater contrasted with throughfall, vegetation played a role of acidification rainwater, while karst soil was of relieving acid through the pH value of soil water contrasted with throughfall. The pH value of water decreased and became thin acid from rainwater to throughfall. On the contrary the pH value of water increased and became thin alkali from throufall to soil water. （2） vegetation-soil could vary chemical characters of rainfall, accelerate elements to move and add the total amount of chemical materials of epikarst water. Those ions concentration increased from rainfall to epikarst water, especially for HCO₃^-, Ca²⁺ and Mg²⁺ ions. HCO₃^-, Ca²⁺ and Mg²⁺ ions concentration in epikarst water were respectively about 25, 14, 30 times of these ions concentration of rainwater. （3） Agricultural environment could accelerate NO₃^- and SO₄^2- ions in soil to be released. The increase of NO₃^- and SO₄^2- ions concentration were respectively 60.4% and 60.7% through epikarst water contrasted with rainfall in Lanhuagou spring watershed. While they were only 5.5% and 37% in Xiangjiayuanzi spring watershed. （4） Ecological was obviously of regulating function for chemical characters of epikarst water. For epikarst spring the max values of temperature, pH and conductivity all lagged behind the Maximum of rain.In summary ecological environment was obviously of affecting regulated function for epikarst water. It affected not only the amount of epikarst water, but also the quality of epikarst water. Good ecological environment was obviously of regulated function for epikarst water. So forest for water and soil conservation must be protected in Preventing and harnessing the desertification and Exploitation epikarst water through ecological recovery so that ecological environment in mountainous karst area would become more and more well.更多还原