广西弄拉兰电堂岩溶泉水化学动态变化

利用多参数自动记录仪对广西弄拉兰电堂泉无降雨时的水化学动态变化监测表明, 水中CO₂ 分压、温度和包气带含水状况是驱动泉水水化学动态变化的主要因素。气温变化、降雨及太阳辐射的昼夜更替, 影响了植物生命活动的强弱。湿季泉水的溶蚀强度明显大于干季, 表现为方解石饱和指数 ( SIC ) 和白云石饱和指数( SID ) 较高。干湿季无降雨气候条件下, 温度对植物活动起主要控制作用。     

川东槽谷区岩溶泉水物理化学动态特征及其环境效应研究——以重庆青木关岩溶槽谷姜家泉为例

以重庆青木关岩溶槽谷姜家泉野外观测试验基地为例,利用CTDP300多参数水质自动记录仪、NITRATAX plussc在线硝氮分析仪及HOBO小型气象站,分别对岩溶泉在不同降雨条件下水化学的动态变化特征进行了监测研究。结果表明:岩溶泉水pH值受偏酸性雨水的影响而降低;水温变化取决于降雨量、持续时间及气温等因素影响。分析认为,电导率的变化随环境的不同而不同,一般降雨环境下雨水的稀释作用仅表现在降雨的开始阶段,之后裂隙含水介质起主要作用;暴雨环境下雨水的稀释作用贯穿整个降雨过程,地下河水质主要受岩溶管道裂隙控制,水动力作用占主要地位。NO3-含量与电导率变化呈正相关,都与降雨量密切相关,从而说明降雨是导致岩溶区土壤元素流失的主要原因,也是造成岩溶山区地下水污染的重要原因。岩溶泉水化学动态变化的监测研究对于解决岩溶石山区居民的饮水、水土保持及石漠化治理具有重要意义。     

垂直气候带岩溶动力系统特征研究——以重庆金佛山国家级自然保护区为例

利用CTDP300多参数自动记录仪对重庆金佛山国家级自然保护区碧潭泉和水房泉的降雨量、水位、水温、pH值、电导率进行了监测。结果表明,不同海拔高度的表层岩溶泉水化学对环境变化十分敏感,且具不同的表现形式,气温和土壤CO2浓度是引起水化学动态变化的两个重要因子。位于海拔较低的碧潭泉气温,土壤CO2浓度相对较高,岩溶作用也相对强,位于海拔较高的水房泉则相对较弱。受气温控制,前者的水温、pH表现出明显的白天高,夜间低的昼夜变化规律。降雨过程中,至少有两种效应在影响水化学性质:雨水的稀释效应和CO2效应,前者对碧潭泉水化学变化影响较大,降雨可引起泉水电导率、水温及pH的显著下降,降雨强度越大,下降速度与幅度越大,而从泉水电导率下降、pH值略有上升看,两者均对水房泉的水化学变化产生了影响。     

岩溶水系统的水化学曲线及其在水文地质研究中的应用

为了认识水文地质条件与岩溶泉水化学之间的关系,以西南地区的6个典型岩溶水系统丫吉试验场S31号泉、毛村地下河、官村地下河、陈旗岩溶泉、青木关地下河以及金佛山水房泉为例进行研究。通过对比发现,在这些强烈非均质的山区裸露型岩溶水系统中,仪器能够实现自动化监测的电导率、温度和pH值等指标的水化学曲线存在差异。分析可知控制水化学变化的主要因素如下:首先是降雨补给引起系统的水量与碳酸盐岩溶解过程的变化;其次是CO₂气体随降雨进入含水层,促进碳酸盐岩的溶解;最后是地表污染物的淋滤。当电导率、水温、pH曲线出现降低和碳酸盐岩矿物饱和指数下降时,反映的是岩溶水的稀释作用;当电导率曲线出现高峰时,反映的是岩溶水补给的CO₂效应,此时水中二氧化碳分压(p_CO2)升高;当场雨中水化学曲线的变化滞后于水文动态曲线时,反映的是岩溶管道的活塞流效应;与人类活动有关的NO₃^-等污染物质量浓度在降雨后出现高峰,反映土壤的降雨淋滤作用,并可能影响电导率的变化趋势。某个系统的水化学曲线趋向于经常出现某几种效应,并且彼此的类型不同,表明了降雨补给的面状渗流方式和集中灌入方式对岩溶水影响的强弱不同,以及系统在径流方式和调蓄机制上的差异。一般而言:以面状补给方式为主的系统,水化学曲线多表现为CO₂效应,较少出现稀释作用;而岩溶发育强烈的系统,降雨补给受控于溶蚀裂隙和管道,其水化学曲线较多出现稀释作用,较少出现CO₂效应;以管道为主要径流方式的系统易出现活塞流效应,而包气带厚度大和含水层储水能力强的系统水化学变化被减弱。     

典型表层岩溶泉水短时间尺度动态变化规律

通过多功能自动化监测记录仪CTDP300,对金佛山表层岩溶泉碧潭泉物理化学性质的昼夜变化过程进行了研究.短时间尺度监测表明,岩溶动力系统对环境变化比较敏感,响应及时,水的物理化学性质昼夜动态变化在不同气候条件下有不同表现.在无雨条件下,水温的变化与气温基本一致,电导率峰值区滞后温度数小时,这可能与植被从光合作用向呼吸作用转变导致大气CO₂浓度产生较大的梯度变化有关,而这种梯度十分有利于岩溶作用的进行,但由于植被覆盖和地质构造等因素的差异,滞后时间有较大不同;在暴雨期间,虽有植被和土壤的阻挡和调蓄作用,降雨对碧潭泉岩溶水还是有较强的稀释作用,但开始降雨后数小时左右,表层岩溶带高裂隙率和渗透性开始发挥作用,水动力作用和CO₂效应逐渐占主导地位.     

太行山北段金龙洞岩溶泉水化学及同位素动态特征

以太行山北段金龙洞岩溶泉为研究对象,通过数理统计.、离子比值及饱和指数等方法,分析泉水水化学和同位素动态特征、水中主要离子来源及演化、水-岩相互作用过程等内容。结果显示:(1)金龙洞泉补给来源为大气降水,泉流量对其响应程度高,泉流量较小时,水中主要离子含量相对高,水化学类型为HCO₃·SO₄-Ca·Mg型,泉流量大时,水中离子含量低,水化学类型为HCO₃-Ca、HCO₃·SO₄-Ca型,泉流量增加引起的稀释作用对离子含量影响明显;(2)控制泉水水化学特征的主要因素为溶滤作用和稀释作用,且Ca²⁺、Mg²⁺、HCO₃^-主要来源于碳酸盐岩溶解,SO₄^2-、Na⁺、K⁺、Sr主要来源于安山岩中长石、黄铁矿等矿物的风化溶解,NO₃^-则来源于人类活动;(3)降水集中期,泉...     

不同类型表层岩溶泉水源划分及对降雨的响应

表层岩溶泉的水文水化学特征是认识岩溶含水介质结构的重要手段。基于泉域水文地质调查,2018年对广西环江木连小流域内降水和泉水流量及电导率进行监测,利用端元模型与电导率频率分布分析方法,解析表层岩溶泉径流来源及对降雨的响应特征。结果表明：（1）年尺度上,受驱替作用排泄的水流分别占季节泉、常流泉总径流的32.3%和23%;(2)次降雨过程季节泉和常流泉径流均以驱替含水层中未联通的“旧水”为主,强降雨条件下存在的雨水稀释现象仅约占3.6%;(3)季节泉在次降雨过程中受多重水流补给且对降雨响应敏感,其中管道流和壤中流分别占23%、34.2%,以基质或岩溶裂隙释放的重力水流仅占10.5%,导致持续供水能力较差;（4）常流泉补给来源单一,次降雨过程中主要受到以基质或岩溶裂隙排泄的重力水补给（77%）,具有较高的有效涵养地下水资源功能及供水可持续性能力。     

典型表层岩溶动力系统的环境敏感性研究--以广西马山县弄拉峰丛洼地为例

利用多参数自动记录仪(CTDP300)对广西马山县弄拉监测站的降雨量及表层岩溶泉水的水位、水温、pH值、电导率进行了监测。结果表明,系统对环境变化响应及时。其地球化学行为表现为明显的季节与昼夜动态变化,且在不同的气候条件下,水化学动态变化有不同的表现。在正常气候(无雨)条件下,水温、pH与电导率之间具有较好的正相关关系。暴雨期间,降雨开始阶段稀释作用明显。降雨中后期,CO2效应逐渐占主导地位。因此有必要把水、岩、CO2气体作为一个整体来解释表层岩溶作用的水文地球化学行为。     

水-岩-气相互作用引起的水化学动态变化研究--以桂林岩溶试验场为例

利用多参数自动记录仪对桂林岩溶试验场的降水量、水位、水温、pH值和电导率进行了监测,数据采集间隔根据参数变化的程度由2min到1h不等。结果发现,岩溶裂隙水在洪水期间pH值呈降低趋势,而电导率呈升高的不寻常变化。与此相反,对于岩溶管道水,同样是在洪水期间,它的pH值是升高的,而电导率呈正常的降低。考虑到Ca2 和HCO-3分别为地下水中主要的阴阳离子(>90%),及它们与电导率的线性关系,计算得到了洪水期间方解石的饱和指数(SIc)和水的CO2分压(Pco2)的变化情况。发现洪水时裂隙水的Pco2高于正常情况的Pco2,而它的SIc值比正常情况低。与此相对,对于管道水,尽管同一洪水期间其SIc降低,但Pco2也降低。从这些结果,可以推断,至少有两个关键的过程控制着洪水期间的水化学变化。一个是雨水的稀释作用,另一个是水-岩-气的相互作用。然而,对于裂隙水来说,后者的作用可能更重要,即在洪水期间,高浓度的土壤CO2溶解于水中,则更具侵蚀性的水能溶解更多的石灰岩,从而增强水的电导率。而对于管道水,雨水的稀释作用更重要,因为研究区较高的pH和低电导率的雨水能更快地通过管道流出,所以,要了解岩溶系统水化学的变化,仅考虑水-岩相互作用是不够的,我们还必须重视CO2气体对岩溶系统中水化学变化的影响。总之,水-岩-气相互作     

岩溶溪流的脱气作用及碳酸钙沉积--以重庆市南川区柏树湾泉溪流为例

以一定间距监测水体中pH、电导率、溶解氧等水化学参数及HCO₃-、Ca2+等阴阳离子浓度,揭示了重庆市南川区柏树湾泉及其下游溪水的水化学的空间特征。泉水出露地表后,CO₂溢出导致溪流水的水化学特征沿流程发生有规律的变化,并促使溪水达到过饱和状态而产生明显的碳酸钙沉积。研究结果表明,脱气作用导致溪水的HCO₃-浓度、Ca2+浓度、电导率（EC）和CO₂分压沿流程逐渐递减,pH值及常见碳酸盐矿物的饱和指数逐渐升高。泉水出露时水中CO₂浓度与自由大气之间的浓度梯度是影响脱气速率的主要因素,但溪渠的水力坡度也对脱气速率也有一定影响。地下水出露至泉口处的脱气程度,是影响溪流碳酸钙沉积的决定性因素。旱季泉水流量较小,泉口处脱气程度较大,并且溪水的Ca2+浓度含量较高,再加上溪流沿途的水体扰动加速CO₂溢出,以及溪渠内的枯枝落叶和其他物质的吸附等,皆有利于碳酸钙沉积。     

High-resolution study on the hydrochemical variations caused by the dilution of precipitation in the epikarst spring: an example spring of Landiantang at Nongla,Mashan, China

In addition to rainfall, high-resolution measurements of water level, pH, specific conductivity and temperature of Landiantang epikarst spring at Nongla, Mashan county in Guangxi Province, China were recorded in summer rainy season by using a data logger with time interval of fifteen minutes. Water from the spring issues along a karst conduit. During the rainstorms in summer, it was found that the pH and temperature of Landiantang spring increased while its specific conductivity decreased. As HCO₃ ⁻, Ca²⁺ and Mg²⁺ are the dominant ions, linear relationships between concentrations of those ions and specific conductivity were developed. According to the ion concentrations from the linear relationships, the saturation indexes of calcite (SI_C), the saturation indexes of dolomite (SI_D) and CO₂ partial pressure (Log ) of the spring were calculated. Results indicated that the Log of the spring during the rainstorms was lower than that without rain, and its SI_C and SI_D was also lower. Combined with the characteristics of the epikarst zone, it was inferred that the above results were caused by the dilution of rainwater, because overland flow with high pH (due to neutralization of carbonate rock dusts in the air to rainwater) and low specific conductivity traveling through the conduit rapidly during rainstorms, showed greater influences on the hydrochemical variations of the epikarst spring.     

表层岩溶系统水化学成因及植被恢复条件下变化趋势——以广西马山弄拉兰电堂泉为例

常见的碳酸盐岩主要有灰岩和白云岩, 两者的岩溶作用机理不同, 因而常形成不同的地貌格局。在我国西南地区, 若在小范围内有灰岩和白云岩出露时, 往往在山体陡峭的部位出露质纯层厚的灰岩, 而山间平原多出露白云岩。这种地层组合结构致使表层岩溶带的发育具有独特的双重岩性结构。基于兰电堂表层岩溶系统的研究, 发现绝大部分水样的水化学类型均为HCO₃-Ca·Mg型, 其主要阳离子Ca²⁺和Mg²⁺质量浓度的季节动态变化趋势不明显, 但对短期降水稀释效应及森林植被CO₂效应的响应则非常迅速。将降水量小且比较均匀的8、9、10及12月水样的ρ(Ca²⁺)和ρ(Mg²⁺)关系曲线定义为"同比例溶解线", 并用其判别不同降水条件下泉水化学成分差异的成因。另外, 为了研究次生森林生态功能逐步恢复条件下岩溶作用强度的变化趋势, 对近10年来弄拉表层岩溶泉水化学组分进行分析对比, 发现岩溶水化学中主要阴、阳离子浓度均有增加趋势, 也进一步佐证了森林植被的岩溶效应。     

Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China

Nongla, a typical karst dynamic system (KDS) monitoring site, is located at Nongla Village, Mashan County, Guangxi, China. The data from a Greenspan CTDP300 multichannel data logger indicates that the KDS is highly sensitive to environmental changes. Multi-day and diurnal physico-chemical composition of epikarst spring water is quite different under different climatic conditions. During a day with no rainfall, water temperature and air temperature have similar variations. Electrical conductivity (EC) has good positive correlation with pH value and water temperature. During rainstorms, the physico-chemical composition of the spring water is initially strongly effected by dilution, pH and EC drop rapidly. However, half to one hour later, EC returns to normal and the CO₂ effects will be the dominant physical effect. This is due to the high fissure rates and high permeability in the epikarst zone. Dilution effects were observed during the entire rainstorm event,whereas, it only acts during the earliest period of light rain. Therefore, it is necessary to examine the water–rock–CO₂ combination as a whole system to explain the hydrochemical behavior of epikarst processes.     

Characterizing snowmelt anomalies in hydrochemographs of a karst spring,Cumberland Valley,Pennsylvania (USA): evidence for multiple recharge pathways

Conductivity, water level, air temperature, and depth of snowpack were monitored during a 26-day melt period of 88-cm-deep snowpack at a karst spring to characterize internal runoff and diffuse infiltration. Chloride from road salt provided a tracer and the snowpack a recharge source during the melt period. The melt period was divided into phases based on air temperature and chemograph pattern. For the first and third phases, mean air temperatures were below freezing, but above freezing during the second and fourth phases. During the first phase when the temperature peaked above freezing, conductivity typically spiked 10–50 μS/cm, suggesting input of road salt from conduits. When the snowpack continuously melted, conductivity and water-level trends were upward with smaller daily spikes in conductivity indicating infiltration from the dilute snowpack. This pattern suggests that road salt input continued when snowmelt recharged through the epikarst, but at lower concentrations than the conduit input. Refreezing of the snowpack and shallow subsurface for a brief period interrupted the recharge, and there was no longer a sawtooth pattern of conductivity. It is apparent that frozen conditions did not cease recharge because a dual recharge process was evident. While dual recharge from internal runoff and diffuse infiltration occurred, the portions varied because of changing melting rates. Observed patterns indicated internal runoff dominated during frozen periods because recharge water moved as overland flow across a frozen surface to focused pathways. Diffuse infiltration became available during warmer periods because subsurface thawing allowed the snowmelt to penetrate the epikarst. Results of snowmelt monitoring in spring discharge indicated the transient nature of karst recharge.     

湖南保靖县白岩洞地下河流域水文地球化学特征研究

白岩洞地下河系统工程主要是解决保靖县城供水水源问题。本文通过三个时段的大量野外实测数据,分析了白岩洞地下河流域内岩溶泉、地表水体和地下河水的岩溶水文地球化学特征及其动态变化。结果显示,该流域内岩溶泉可分为两个主要类型,一类是与深循环有关、沿区域断层带分布,其水文、水化学动态相对稳定,水化学变化受深源CO2 浓度控制; 另一类为岩溶表层带泉,受地表环境、降雨量影响大,水化学动态变化较大。而地下河及其支流水的水化学变化特征介于表层带岩溶泉和地表水之间,其三个时段的变化规律跟表层带泉相似,主要水化学指标枯季( 12月) > 雨季1(次年4月)> 雨季2(次年7月) ,说明明显受降雨的稀释作用控制。      

Functioning of a karst aquifer from S Spain under highly variable climate conditions,deduced from hydrochemical records

Over a period of three hydrological years during which precipitation was highly variable, measurements of discharge, electrical conductivity, temperature and chemical components of the water at the Cañamero spring (southern Spain) were taken in order to characterise the hydrogeological functioning of the karst aquifer that it drains. The results obtained from analysis of the frequency distribution of electrical conductivity data revealed histograms with a plurimodal morphology (up to 5 modes) and a range of variation that increased with greater pluviometry during the study period. The discharge from this spring increased sharply a few days after major rainfall episodes and, when the discharge reached a value of approximately 3.73 m³/s, an overflow spring started to function. During high-water periods, there were sudden and large falls in EC, temperature and all the chemical components dissolved in the water. This high variability reflects the predominance of groundwater flow through karst drains, a typical feature of conduit flow systems. The considerable hydrochemical heterogeneity observed is caused by the mobilisation of important volumes of recharge waters from shallow areas of the aquifer (soil, epikarst) towards the discharge point, with greater participation of the unsaturated zone during high-water conditions, and a more active role played by the saturated zone during low-water conditions. In karst systems such as the one drained by the Cañamero spring, it is important to monitor several responses (hydrodynamic, hydrothermal, hydrochemical, etc.), with an appropriate sampling frequency and under different hydrometeorological conditions, in order to achieve an adequate hydrological characterisation. This is fundamental for planning, management and protection of groundwater in karst aquifers.     

峰丛洼地的坡地径流成分划分

峰丛洼地的石质坡地具有独特的包气带结构和产流模式,其表面岩石裸露,土壤薄且呈现斑块状分布,下部发育表层岩溶带.表层岩溶带的存在决定了石质坡地的产流模式.原本不透水的岩石表面成为"筛子",表层岩溶带和下部包气带之间的界面成为重要的产流界面,称之为表层岩溶带产流.石质坡地的径流是表层岩溶带产流、超渗产流、饱和产流的集合.由于岩溶动力系统的差异导致来自不同界面的径流的温度、pH、电导率、方解石溶解饱和指数(SIc)和二氧化碳分压(P_(CO2))也不同.利用径流的物理、化学曲线对石质坡地的径流进行初步的定性划分,将径流分为洪峰和基流.洪峰的上升段由超渗产流和饱和产流构成,退水过程以及基流则主要是由表层岩溶带径流提供.     

森林覆盖的喀斯特地区表层岩溶带的产流阈值

选择中国南方喀斯特森林石山地区的表层岩溶带中出露的泉水为研究对象,通过对泉水水位、pH、电导率、水温和降水的连续监测,发现表层岩溶带的降水补给的产流阈值为12mm。同时分析了不同降水补给引起的表层岩溶泉pH、温度、电导率的变化规律。雨季pH在降水后出现暂时的降低,电导率和水温出现暂时的升高。旱季pH、电导率等表现出比雨季更复杂的变化。按照水位、pH、电导率、水温对降水补给的反应的强弱不同,将表层岩溶带对降水的反应分成三个等级。第一等级为表层岩溶泉的流量等都不发生变化;第二等级是表层岩溶泉的4个指标有部分发生微小缓慢的变化;第三等级是表层岩溶泉的4个指标发生显著的变化。表层岩溶带的产流阈值是区别有效降雨和无效降水的标准,并对理解岩溶地下水的形成有帮助。     

水化学对水体着生微型生物群落组成与丰度的影响 ——以桂林毛村表层岩溶泉、砂页岩裂隙泉为例

用载玻片作人工基质,放置在桂林毛村岩溶生态试验场碳酸盐岩分布区表层岩溶泉水和砂页岩区裂隙泉水中,开展着生微型生物群落结构研究。通过对比研究发现:毛村表层岩溶泉水中p H、游离CO2、固定CO2、K+ 、Na+ Ca2+ 、Mg2+ 、Cl- 、HCO3- 、NO3- 和SO42- 浓度均较砂页岩区裂隙泉水的高; 砂页岩区水体中着生生物群落的种数和总个体密度均比岩溶区的低;富钙、偏碱性的岩溶泉水体中形成的着生藻类群落结构以硅藻门为主,而砂页岩区裂隙泉水的着生藻类群落结构则以绿藻门为主。岩溶泉水体的这种着生藻类群落结构的形成与岩溶泉水的富钙、偏碱性有很大的关系。