毛乌素沙地沙柳灌丛降雨截留与树干茎流特征

通过对毛乌素沙地沙柳灌丛降雨截留量及树干茎流的实验观测,分析了降雨量和降雨强度对沙柳灌丛的降雨截留量、穿透雨量和树干茎流量的影响,并确定了截留量、穿透雨量和树干茎流量在降雨分配中的百分数。实验期间降雨总量为136.5 mm,沙柳灌丛的截留量、穿透雨量和树干茎流量分别为34.0、98.5和4.0 mm,占降雨量的百分比分别为24.9%、72.2%和2.9%。沙柳灌丛的降雨截留量、穿透雨量和树干茎流量与降雨量和10 min最大雨强之间均呈显著正相关,而截留量、穿透雨量占降雨量的百分比与降雨量之间呈显著的双曲线函数关系。     

太行山地区不同植被林冠截留降水的研究

通过穿透降雨和树干径流自动采集系统,对油松、侧柏、刺槐三种植被截留实验数据进行了分析。结果表明,三种植被林内穿透降雨与林外天然降雨都具极显著的正相关线性关系,林冠截留量与林外降雨量呈幂函数关系,平均截留率大小关系为油松>侧柏>刺槐。相同林外降雨量下产生的树干径流量大小关系为刺槐>侧柏>油松。     

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。     

岩溶含水层降雨非线性入渗补给的处理方法

岩溶地区由于发育有溶隙、漏斗以及落水洞等特殊的地质结构,使其具有特殊的降雨入渗方式--不同的雨量级有不同的有效降雨入渗补给.本文根据岩溶地区这一特性,提出降雨量系数的概念,来调节不同的雨量级所产生的不同的降雨入渗量.并将降雨量系数用于山西延河泉岩溶水系统数值模拟中,得到了很好的效果.     

我国西南岩溶区表层岩溶带的水文动态分析

以西南地区10个表层岩溶泉的长期观测和自动化监测数据为基础,分析了表层岩溶带的水文动态特点。表层岩溶泉的月径流量变化和连续的水位变化表明表层岩溶带具有水文动态不稳定的共性,不稳定性和表层岩溶带的功能和降水有关。根据表层岩溶带的形态和水文动态变化特点进行分类,认为以间互型碳酸盐岩为基础的溶丘洼地表层岩溶带和以连续型碳酸盐岩为基础的峰丛洼地表层岩溶带是西南岩溶区两种重要的表层岩溶带类型。溶丘洼地表层岩溶带相对于峰丛洼地表层岩溶带具有较连续的土壤盖层和较大的表层岩溶泉密度以及较稳定的水文动态变化。白云岩上发育的表层岩溶带水文动态比灰岩稳定,森林覆盖下的表层岩溶带的水文动态比灌木林稳定。表层岩溶带的水文动态受控于它的补给类型和径流特征。土壤层的厚度和植被类型会使表层岩溶带集中补给的比例发生变化,而岩性则通过影响表层岩溶带的空隙类型来控制径流特征。     

柑桔园林下穿透雨的分布特征

研究了柑桔林下穿透雨的分布特征,结果表明:在测定期间,穿透雨量占总降雨量的68.3%,5月的穿透雨量最大(245.1 mm),而穿透雨率最大值(73.3%)出现在8月。穿透雨量与降雨量具有显著相关性(p<0.01),而穿透雨率与降雨量和降雨强度的相关性均达到显著水平(p<0.05)。柑桔林下穿透雨显示出明显的空间变化,各观测点间穿透雨率具有显著性的差异,而且穿透雨的空间异质性(穿透雨率的变异系数CV)随着降雨量或降雨强度的增加而降低,聚类分析也显示出穿透雨在不同观测点间具有差异性。柑桔林下穿透雨呈现明显的聚集效应。     

典型岩溶包气带洞穴滴水水文过程研究——以桂林硝盐洞为例

选取桂林丫吉试验场硝盐洞为研究对象,通过示踪试验和高分辨率水文水化学监测,确定滴水补给来源,研究典型岩溶包气带洞穴滴水对降雨响应的水文过程。研究结果表明,硝盐洞XY5滴水主要受到两种径流成分补给,即集中补给的管道流和弥散流。硝盐洞上部包气带中可能存在表层岩溶带含水层,长期维持滴水流量。滴水流量、电导率和示踪剂浓度的峰值均出现在强降雨时段,表现出快速响应的管道流特征,存在降雨阈值引起硝盐洞滴水降雨响应。降雨前岩溶含水层水分条件是包气带水文响应差异的主要原因,雨季滴水对降雨响应迅速,XY5滴水对降雨响应的滞后时间为10 h;而旱季对降雨的响应滞后明显,滞后时间达9.8天,体现了土壤和表层岩溶带的调蓄作用。74.4 mm降雨量是旱季转雨季滴水响应的降雨阈值。借助于洞穴滴水的水文动态变化和示踪试验技术对于研究包气带水文过程,深入了解岩溶含水层结构及特征,揭示岩溶区降雨入渗补给机制具有重要作用。     

表层岩溶带调蓄系数定量计算--以湘西洛塔赵家湾为例

本文以湖南洛塔赵家湾表层岩溶系统为例,综合利用水位、降雨量、蒸发量及泉流量等长观资料,分别对不同降雨特征下的表层岩溶带调蓄系数进行了定量计算,并对影响表层岩溶带调蓄能力的因素进行了分析。计算得到丰水期赵家湾表层岩溶带调蓄系数为0 14～0 2 8,明显小于枯水期调蓄系数0 44 ;但丰水期久旱后表层岩溶带的调蓄能力接近于枯水期;在丰水期,场雨和连续降雨时的调蓄能力比间歇降雨时的小近1倍。实例计算表明:赵家湾表层岩溶带具有一定的调蓄能力,其地下迳流滞后于降雨至少3d ,调蓄系数确实可以用来定量评价表层岩溶带的调蓄能力。     

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。     

降雨特征及小气候对秦岭油松林降雨再分配的影响

为了研究降雨特征及小气候对秦岭天然次生油松林冠层降雨再分配的影响,连续3年观测降雨事件发生时油松林林外降雨、穿透降雨、树干茎流以及降雨特征和小气候因子,进行各因子间的相关性和多元回归分析。结果表明:降雨量级是影响林冠降雨再分配的最主要因素,穿透降雨量与降雨量、降雨量和降雨历时交互项、相对湿度呈正相关,与降雨历时和温度呈负相关。树干茎流量与降雨量、降雨量和温度交互项呈正相关,与温度呈负相关。林冠截留量与降雨量、降雨历时和温度呈正相关,与降雨量和降雨历时、温度的交互项呈负相关。雨前干燥期、风向、风速、蒸发速率、光合有效辐射和净辐射与穿透降雨量、树干茎流量和林冠截留量均无相关性。     

利用EARTH模型计算河北栾城地下水垂向补给量

准确计算地下水的垂向入渗补给量是合理评价和利用地下水资源的基础.EARTH模型是一种集中参数的水文模型,可刻画水流在包气带中的运移过程,弥补黑箱模型的不足.以中国科学院栾城农业生态试验站的地下水位观测资料以及气象资料为基础,综合运用降水、蒸发、土壤水、地下水动态观测资料,利用EARTH模型计算了河北平原地下水垂向入渗补给量.计算结果表明,2003年1月1日至2005年8月31日期间,栾城农业生态试验站在降水量1404.1 mm、灌溉量1050.0 mm的条件下地下水入渗补给量为487.2 mm,平均年入渗补给量为182.6 mm, 占降水和灌溉总量(2454.1 mm)的19.9%.在模拟结果的基础上,对不同年份的降水量(含灌溉)和入渗补给量分布的对比分析表明,河北栾城地下水补给滞后现象明显,在研究时间段内峰值滞后18～35 d.     

The vulnerability of karst springs—a case study of the Hubelj spring (SW Slovenia)

The hydraulic behaviour of the karst aquifer in the Hubelj spring catchment area (SW Slovenia) was studied by using an indirect research method based on natural tracers. The variations of natural tracers (in precipitation and in groundwater) during the storm event made possible the separation of the Hubelj spring storm hydrograph by the three-component separation technique. The results produced information on the aquifer recharge, storage and discharge processes, as well as on the mechanisms that affected them. They verified the so-called epikarst hypothesis presuming that an important part of a karst aquifer recharge reaches rapidly and intensively from the epikarst zone. It was demonstrated that epikarst water could occupy up to 50% of the spring discharge during precipitation events. This phenomenon could have important consequences on protection and management of the problems of karst aquifers, including engineering problems in karst areas. With this respect the results could give way to new engineering ideas.     

Water source partitioning among trees growing on carbonate rock in a subtropical region of Guangxi, China

It is not clear how the water sources are used by trees in typical karst areas of Guangxi, China. Trees growing on rigid carbonate rock can primarily use spring water, precipitation-recharged soil water or a mixture of the two. In this study, the Nongla karst dynamic monitoring station in the southwest of Guangxi, China, was observed. To determine the water sources accessed by trees growing on rigid carbonate rock, seasonal change of isotope ratios (δ¹⁸O and δ D) in twig sap, soil water, rainfall and spring water were measured. Stem water samples plotted to the right of the meteoric water line indicates utilization of water sources subject to evaporative isotopic enrichment. Trees growing on rigid carbonate rock in the southwest of China used rainfall directly in the rainy season. Adult trees tended to use deeper water stored in the epikarst zone, while the young ones used soil water when precipitation decreased. In the dry season, all trees sampled depend mostly on water stored in the epikarst zone. Spring water was the major water source for all of the tree species investigated in the dry season. In conclusion, these data indicate that trees growing on rigid carbonate rock in southwest China depend mostly on water stored in the epikarst zone. Therefore, water storage in the epikarst zone is the essential water source for trees growing on carbonate rock in southwest China.     

Hydroecogeochemical effects of an epikarst ecosystem: case study of the Nongla Landiantang Spring catchment

A typical small-scale epikarst ecosystem usually consists of an epikarst zone, soil and vegetation. In this study, to determine the hydro-eco-geochemical effects of an epikarst ecosystem in subtropical humid area, the samples of vegetation, soil, soil microbes, rainfall, throughfall, stem flow, soil water and epikarst springs of Nongla Village, Mashan County, Guangxi in China were collected and analyzed. The research results have shown in the epikarst ecosystem, the conductivity, temporary hardness and total carbon increased continuously in hydro-ecochemical cycle; the vegetation–soil system conducted the transformation and transference of carbon in hydro-ecochemical cycle; the vegetation layer was the major source for organic carbon, while the soil layer was of the important chemical field for the conversion of organic/inorganic carbon and HCO₃ ^–, which would affect the epikarst dynamical system; for most ions, the vegetation layer and shallow soil layer presented more leaching effect than absorption, in contrast, the deep soil layer behaved oppositely. The vegetation layer and shallow soil layer leached ions, and deep soil layer absorbed them. With the plant community presenting in a positive succession, the epikarst ecosystem trended to be stabilized gradually, which made the hydro-eco-geochemical effects to be adjusted and controlled more effectively.     

湖南洛塔干河猪场表层岩溶泉BP人工神经网络分析

采用湖南洛塔地区干河猪场表层岩溶泉日降水— 日平均流量长期观测资料训练BP人工神经网络,建立了该泉的径流预测模型。通过模型训练输出结果中降水量对径流量的贡献率,分析了表层岩溶带对水资源的调蓄能力。结果表明,降水对泉流量的显著影响时间为6天,当天和前一天的降水对当天的流量影响最大;干河猪场表层岩溶带可调蓄26. 1%的岩溶水资源;干河猪场泉的全部流量可作为可采资源量,平均流量5. 8 L /s,可满足目前的引水需求;通过改善土壤和植被覆盖条件可提高其调蓄能力。      

Spatial and temporal variation of groundwater recharge in shallow aquifer in the Thepkasattri of Phuket,Thailand

Whether groundwater resources can be sustainably utilized is largely determined and characterized by hydrogeological parameters.Estimating the groundwater recharge is one of the essential parameters for managing water resources and protecting water resources from contamination.This study researched the spatial and temporal variation of groundwater recharge in the Thepkasattri sub-district through integrating chloride mass balance(CMB)and water table fluctuation(WTF)methods.The chloride content of representative rainfall and groundwater samples was analyzed.Besides,WTF method was adopted from groundwater level data from 2012 to 2015.According to the CMB method,the mean recharge was estimated to be 1172 mm per year,accounting for 47%of the annual rainfall.Moreover,the estimated recharge from the WTF method took 26%of annual rainfall in 2015.The recharge was underestimated according to the WTF method,because of the uncertainty in specific yield estimates and the number of representative wells in the study area.Moreover,the correlation between rainfall and water table fluctuation data indicated the positive linear relationship between two parameters.The spatial recharge prediction indicated that recharge was higher(1200-1400 mm/yr)in the eastern and western catchment,while that in the central floodplains was between 800 mm/yr and 1100 mm/yr.In addition,low recharge value between 450 mm/yr and 800 mm/yr was observed in the south-west part of Thepkasattri.The spatial variation of recharge partly reflects the influences of land use and land cover of the study area.     

Determining the groundwater potential recharge zone and karst springs catchment area: Saldoran region,western Iran

Assessing the groundwater recharge potential zone and differentiation of the spring catchment area are extremely important to effective management of groundwater systems and protection of water quality. The study area is located in the Saldoran karstic region, western Iran. It is characterized by a high rate of precipitation and recharge via highly permeable fractured karstic formations. Pire-Ghar, Sarabe-Babaheydar and Baghe-rostam are three major karstic springs which drain the Saldoran anticline. The mean discharge rate and electrical conductivity values for these springs were 3, 1.9 and 0.98 m³/s, and 475, 438 and 347 μS/cm, respectively. Geology, hydrogeology and geographical information system (GIS) methods were used to define the catchment areas of the major karstic springs and to map recharge zones in the Saldoran anticline. Seven major influencing factors on groundwater recharge rates (lithology, slope value and aspect, drainage, precipitation, fracture density and karstic domains) were integrated using GIS. Geology maps and field verification were used to determine the weights of factors. The final map was produced to reveal major zones of recharge potential. More than 80 % of the study area is terrain that has a recharge rate of 55–70 % (average 63 %). Evaluating the water budget of Saldoran Mountain showed that the total volume of karst water emerging from the Saldoran karst springs is equal to the total annual recharge on the anticline. Therefore, based on the geological and hydrogeological investigations, the catchment area of the mentioned karst springs includes the whole Saldoran anticline.     

Flow and solute transport monitoring in the karst aquifer in SW Slovenia

The role of the unsaturated zone in the karst aquifer hydraulic behaviour was brought into focus in these studies of the catchment of the Hubelj spring (SW Slovenia). The variations of natural tracers in precipitation and in groundwater during a summer storm event made it possible to trace local flow and solute transport in the observed aquifer. The results produced data on the aquifer recharge, storage and discharge processes, as well as on mechanisms that affected them, which reflects a karst groundwater dynamics also at a regional scale. They point out the significance of effects of the fast preferential flow—epiflow that is the main factor controlling solute/contaminant transport towards the aquifer saturated zone. Numerous arguments indicate that the karst aquifer flow and solute transport mechanisms depend on the hydraulic behaviour of the epikarst zone.