Nitrogen Gas Saturation in Karst Springs Varies Throughout the Day

This experiment examined the fluctuations in nitrogen gas supersaturation throughout the day in three karst springs (upper, side, and lower) at McNenny State Fish Hatchery, rural Spearfish, Lawrence County, South Dakota, USA. Total gas pressures, oxygen percent saturation, and nitrogen percent saturation were recorded six times/day on eight days over a 26-day period in each of the three springs. Total gas pressure did not vary significantly throughout the day in any of the springs. However, percent oxygen and nitrogen saturation were significantly different throughout the day in all three springs. The highest mean (SE) nitrogen supersaturation value of 118.5 (1.1)% was observed in the lower spring at 07:00. The lowest mean nitrogen supersaturation values were 114.5 (1.1)% at 13:00 in the upper spring, and 114.2 (0.2)% and 113.1 (0.7)% at 15:00 in the side and lower spring, respectively. At 118% nitrogen supersaturation, gas bubble disease is likely to occur in fish, resulting in potentially high levels of mortality if untreated spring water was used for fish production. The results of this study indicate the importance of recording nitrogen gas levels at sunrise or early in the morning, when nitrogen is highest and oxygen is lowest, to obtain accurate and reproducible data.

Efficacy and Challenges of Using Springs for Early Detection of Contaminant Release from Waste Disposal Facilities Constructed in Karst Terranes

Early detection of groundwater contamination from waste disposal facilities is challenging in karst terranes. First, one needs to demonstrate that the groundwater system at the study site is monitorable. Both springs and wells are potential monitoring locations if they are effectively connected to the groundwater system, and they are not impacted by any other disposal facilities. Second, due to dynamic responses to recharge events, particularly discharge and chemical constituents at karst springs, multiple-parameter, long-term, and high-frequency monitoring may be required to collect background data. Sampling and analysis plans should be designed to reflect the unique characteristics of the monitoring locations. Characterization of the natural variations in water quality may require sampling efforts under different flow conditions. Third, evaluation of the potential impact of waste disposal units on the groundwater system requires an effective statistical evaluation program. Due to heterogeneity of karst aquifers, intra-locational comparison is generally preferred to inter-locational comparison. Sufficient groundwater monitoring data prior to construction of waste disposal units are required to develop the intra-locational statistical evaluation. In the case study presented in this paper, procedures to address these above-mentioned challenges were presented for two springs using seven dye tracing tests, two spring instrumentations, nine background sampling, flow-weighted concentrations, and an innovative statistical evaluation method were presented. These procedures were developed to evaluate potential contaminant release from a solid waste disposal facility constructed in a relatively isolated karst terrane. Although the specific procedures may not be duplicated, the overall technical approaches discussed in the paper may shed light on groundwater monitoring programs in other karst areas.

Hydrodynamic characteristics of a typical karst spring system based on time series analysis in northern China

In order to study the hydrodynamic characteristics of the karst aquifers in northern China,time series analyses(correlation and spectral analysis in addition with hydrograph recession analysis)are applied on Baotu Spring and Heihu Spring in Jinan karst spring system,a typical karst spring system in northern China.Results show that the auto-correlation coefficient of spring water level reaches the value of 0.2 after 123 days and 117 days for Baotu Spring and Heihu Spring,respectively.The regulation time obtained from the simple spectral density function in the same period is 187 days and 175 days for Baotu Spring and Heihu Spring.The auto-correlation coefficient of spring water level reaches the value of 0.2 in 34-82 days,and regulation time ranges among 40-59 days for every single hydrological year.The delay time between precipitation and spring water level obtained from cross correlation function is around 56 days for the period of 2012-2019,and varies among 30-79 days for every single hydrological year.In addition,the spectral bands in cross amplitude functions and gain functions are small with 0.02,and the values in the coherence functions are small.All these behaviors illustrate that Jinan karst spring system has a strong memory effect,large storage capacity,noticeable regulation effect,and time series analysis is a useful tool for studying the hydrodynamic characteristics of karst spring system in northern China.

Numerical simulation of karst groundwater system for discharge prediction and protection design of spring in Fangshan District, Beijing

As the rapid growth of population and social economy, the situation of water resources shortage in Beijing city becomes more and more serious. Karst groundwater in Beijing has great potential for development. The reasonable exploitation of karst groundwater can enhance the water-supply stability of Beijing city. Firstly, the distribution of springs has been investigated in Fangshan, Beijing, and the characteristics of these springs have also been analyzed. Secondly, the hydrogeological conceptual model has been built, based on this, the groundwater flow numerical simulation model was established, and the parameter identification and validation of the model were performed under groundwater level and spring discharge. The results shows that the simulated values of groundwater level and spring discharge are very close to measured values, and the model can be used for groundwater resources evaluation and spring discharge prediction. Finally, a reasonable exploitation design has been developed with three exploitation scenarios considering the spring discharge protection; meanwhile, the quantity of groundwater resources was evaluated in the karst aquifer. The simulation results indicate that different exploitation yields have a significant impact on spring discharge; and the effective measures should be taken to protect the spring discharge.

Numerical simulation and environmental impact prediction of karst groundwater in Sangu Spring Basin,China

The changes of development and utilization of karst groundwater in Sangu Spring Basin have made the original groundwater resource evaluation unable to meet the needs of future economic development.Based on analysis of existing data,combined with the characteristics of supplement,runoff and draining of regional karst groundwater,the Visual Modelflow software was used to build a numerical simulation model of Sangu spring Basin.The amount of karst groundwater resource and groundwater environment of the Basin were evaluated under different exploitation schemes,and the changes of karst groundwater environment in the future ten years were also predicted.The fitting error which is less than 0.5 m between the calculated value and measured value of the water level in the fitted borehole accounts for 93%.For the lithologically and structurally complex Sangu Spring Basin,the fitting effect of numerical simulation model was ideal.On the basis of the current mining amount of 111.80 million m3/a,the total redistributed exploited amount in the spring region was 61.79 million m3/a.Under the condition that the quantity of recoverable resources reached 173.59 million m3/a and under different precipitation schemes,all constraint conditions were satisfied,such as regional water level drawdown,maximum allowable water level drawdown in every simulated water source area and the flow rate of Guobi Spring.The results will provide a scientific basis for the rational development and utilization of karst groundwater in Sangu Spring Basin.

Hydrochemical Variations of the Karstic Spring and Its Environmental Effects

The groundwater was polluted in some extent by pesticides and fertilizers.There are few research on the monitoring groundwater in karst areas at present. This paper list a case study of the jiangjia spring in Qingmuguan karst valley experimental site,ChongQing China.Rainfall and physico-chemical variations of groundwater were monitored by HOBO

Particle Size Characteristics of Soil in Karst Area with Different Land Use Pattern—A Case Study of Shuifang Spring,Jinfo Mt.,Chongqing

This paper tried to analyze the particle size characteristics of the soil samples in Shuifang Spring catchment area,Jinfo Mt.,Chongqing with different land use patterns that are horse race grassland, rhododendron bush,bamboos,and the grassland near the Shuifang spring.The different land usepattern in karst area is of great affection to the particle size characteristics of soil.The median diameter of the karst surface layer soil becomes gradually smaller and smaller in following sequence:horse race grassland,grassland near the Shuifang Spring,

Influence of precipitation on bacterial structure in a typical karst spring,SW China

Micro-organisms are major components in the environment, which play a key role in groundwater environment. This study aims to investigate the bacterial diversity over time in a typical karst spring named S31 and its response to hydrogeochemical parameters. Quantitative PCR and 16S rRNA high-throughput sequencing was adopted to detect changes of the bacterial community structure. For the correlations between hydrogeochemical parameters and predominant phyla, redundancy analysis were adopted. According to the results, hydrochemical characteristics were controlled by carbonate equilibrium system and dynamic groundwater transformation which was influenced distinctly by precipitation. In addition, the redundancy analysis indicates that HCO_3^-, Ca^(2+), Eh, temperature and cumulative precipitation are the most important hydrogeochemical and environmental parameters to determine the bacterial community structures. That is to say, temperature can influence bacterial abundance by controlling dissolved oxygen content. Precipitation is another important factor which determines the community composition and bacterial structure directly or indirectly. Moreover, acidobacteria, proteobacteria, and bacteroidetes play key roles in response to the environmental factors in the groundwater of karst zones.

Karst caves and hydrology between geodesy and archeology:Field trip notes

The Geodynamics-Earth-Tides-meeting-2016 was held in the Karst, the origin of geologic karst- formation. Surface-rivers are absent, and water flows in channels over distances of 30 km, forming subsurface caves. Geodetic observations allow detecting caves and sense hydrologic flow. The Karst water had been recognized before Romans as provision for man and livestock. Proto-historic remains near the mouth of the underground river suggest the water outpouring from the Karst was associated with deities to be worshiped. Here the geodetic and cultural aspects of the Karst are summarized, illustrating the field trip that had been offered to the participants.

Macroalgae in a spring stream in Shanxi Province:composition and relation to physical and chemical variables

Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.

Karst Groundwater Management through Science and Education

In Southwestern China, karst covers an area of 540,000 km2, and supports a population of approximately 100 million people. This groundwater can easily become highly polluted without effective management. Sound management of karst areas requires the conscientious participation of citizens including homeowners, planners, government officials, farmers and other land-use decision makers. Lingshui Spring was a good example. A series of educational materials were developed and delivered to the local government, residents, and students. A groundwater polluted accident was tracked as a natural tracer test in a spring to increase understanding of the vulnerability of the area’s karst aquifer. More than 200 people attended the communication and training course on groundwater protection and environmental justice law. Several efforts have appeared as a result, such as a proposal for Lingshui water resources protection that was put forward for the first time by Wuming county political consultative conference.

Study on Jinan urban construction planning based on the protection of karst landscape

Study on urban construction planning based on karst landscape protection contributes to sustainable development of urban construction in karst area. Jinan is a city famous for karst spring water. Karst landscape plays a decisive role in urban construction. Through hydrogeological analysis, the distribution characteristics of karst mountain, cave, gully and flat dam in Jinan are analyzed. It is revealed that various karst landforms are involved in the spring circulation process to varying degrees. Some karst landforms have been destroyed in the process of urban construction and the karst landscape has been overexploited resulting in the direct or indirect weakening of spring water recharge and infiltration capacity and the decrease of spring water flow. Through the study of the principle of organic combination of karst landscape and urban construction planning, on the basis of protecting the ecological environment of the south, paying attention to the overall protection of the karst geomorphology system and the principle of accessibility of the karst landscape, the development countermeasures guided by urban planning are put forward based on karst landforms protection. On the basis of fully considering the special karst landform conditions in Jinan, the countermeasures are that the ecological control red line of urban construction planning should be set up based on karst mountains and valleys in southern of Jinan City. It is suggested that the bare carbonate rock continuous mountain foot line in the direct recharge area should be taken as the south control red line of urban development and included in the overall planning. The urban landscape is mainly displayed in the main axis based on karst mountains and springs, constructing East-West Axis-characteristic Landscape Belt along the Wufeng Mountain-Langmao Mountain-Hero Mountain-Qianfo Mountain-Long cave-Panlong cave-Jinping Mountain line and North-South Axis Landscape Belt along the Baotu SpringQianfo Mountain line, Baiquan-Panlong cave line, Baimai spring-Dajian Mountain line. Based on the karst river valleys and the river system, the urban spatial pattern is constructed, forming ecological corridor, restoring infiltration function of river. The form of urban construction should be shaped based on karst landform and the river system. The main form is semi-star like radiation type and the combination of central intensive type and zonal type. Based on the whole protection of karst geomorphology system and the scientific molding of karst landscape, the ecological landscape city with the symbiosis of spring and urban can be built.

晋祠泉域岩溶地下水防污性能评价与水质保护区划分

晋祠泉域岩溶水是太原市生活和工农业生产等重要的水源。文章以新划分的晋祠泉域岩溶水系统为评价对象,在欧洲方法及“水量脆弱性评价”的基础上,选取包气带厚度、入渗补给强度、上覆地层岩性及岩溶含水层的富水性4个指标,进行泉域岩溶水系统防污性能评价及水质保护区划分。结果表明:泉域泉源保护区主要分布在晋祠公园及周边;一级保护区主要分布在汾河主干流、西山山前碳酸盐岩裸露区,屯兰川、天池河及柳林河碳酸盐岩渗漏段等;二级保护区主要分布在泉域北部、汾河北岸等;准保护区主要分布在汾河南岸、东南部的太原盆地地区等。

基于机器学习的西南岩溶泉流量模拟研究

岩溶泉对西南岩溶区生态系统稳定和经济社会发展具有重要意义。受岩溶区独特水文地质结构与多重水流过程控制,岩溶泉流量具有复杂的动态变化特征,机器学习模型为其模拟和预测提供了有效手段。然而,岩溶泉域降雨−泉流量过程及其时空变异特征对机器学习模型结构与模拟精度的影响仍不明晰。本文选取西南典型岩溶泉,基于长短期记忆网络(LSTM)建立岩溶泉流量模拟模型,利用泉域实测逐小时降雨与泉流量序列进行模型训练与验证。在此基础上,分析了不同降雨−泉流量过程对岩溶泉流量模拟精度的影响,以及岩溶水文地质结构对降雨−泉流量响应滞时的控制作用。研究结果显示,山坡岩溶泉与流域出口岩溶泉训练期纳什效率系数(NSE)分别为0.942与0.951,验证期分别为0.831与0.834。对于山坡岩溶泉与流域出口岩溶泉,利用全年实测序列训练的模型预测雨季泉流量存在较大偏差,NSE分别为0.793与0.798,而利用雨季实测序列训练的模型预测雨季泉流量,精度显著提升,NSE分别为0.956与0.962,且此差异在暴雨频繁的5、6、7月尤为显著。受浅薄土壤与表层岩溶带分布影响,山坡岩溶泉LSTM模型时序步长显著小于流域出口岩溶泉。

基于数值模拟的隧洞施工排水地下水影响评价

由于自然条件的改变和人类活动的影响,岩溶泉域出现断流或衰减、区域水位趋势性下降以及水质持续恶化等诸多环境和地质问题,研究隧洞工程施工排水对泉域地下水的影响对于泉域生态环境保护十分必要。依托山西某工程深部隧洞穿越柳林泉域,构建了隧洞工程所在泉域的地下水数值模拟模型(采用MODFLOW软件开发盆地地下水模型),根据地下水长期观测井数据,对模型及相关参数进行验证和率定,通过模型模拟刻画出地下水系统补给、径流和排泄特征,分析工程前期施工以及后期排水对岩溶水水位动态、泉流量的影响以及可恢复性。研究成果表明,由于枝柯-车鸣裕泉域含水层地下水库的调蓄作用,前期和后续施工排水对柳林泉水补给量的影响较小;对枝柯泉域和车鸣裕泉域的区域地下水水位影响明显,预估到2025年底,枝柯镇北部形成降落漏斗。研究方法及成果对其他泉域生态环境保护具有参考价值。

岩溶泉水温度对降雨—流量响应的指示作用

岩溶区土-岩交错、裂隙和管道发育,加大了降雨入渗补给方式和多重水流辨识难度。文章利用贵州陈旗小流域场次降雨、泉流量以及大气、土壤和泉水温度观测数据,识别降雨入渗补给方式、泉流量来源以及热传导机制。结果表明:强度小、历时长的降雨,泉水温度缓慢上升且持续时间长,以“分散入渗补给”和热传导作用为主;随着降雨强度增大、持续时间缩短,泉水温度上升时段缩短、下降快速,以“径流集中入渗补给”和“直接集中入渗补给”为主,热传导减弱、平流作用增强。退水初期泉水温度比泉流量下降快速,后期则相反。指示退水初期泉流量来源于大量细小裂隙水向岩溶管道中释放,后期释放量减小并趋于稳定。

湖北秭归鱼泉洞泉域系统中六六六(HCHs)和滴滴涕(DDTs)的分布、来源与迁移

岩溶区特殊的地形地貌,使得地表环境中的有机氯农药(OCPs)很容易进入地下环境,对地下水的安全构成威胁。采用气相色谱-电子捕获检测器(GC-ECD)对湖北秭归鱼泉洞泉域系统中的典型OCPs——六六六(HCHs)和滴滴涕(DDTs)进行了检测,探究了其时空分布特征、潜在污染来源和迁移特征。结果表明:水体中HCHs质量浓度范围为0.09~5.17 ng/L,土壤和泉沉积物中HCHs质量分数范围分别为0.36~3.67,0.11~2.53 ng/g;水体中DDTs质量浓度范围为0.13~7.16 ng/L,土壤和泉沉积物中DDTs质量分数范围分别为0.22~19.13,0.73~11.53 ng/g,呈现出以DDTs为主的污染特征。水体中HCHs和DDTs质量浓度在冬季最高;土壤中HCHs和DDTs质量分数分别在夏季和冬季达到最高;泉沉积物中HCHs和DDTs质量分数分别在夏季和春季达到峰值。特征比值结果显示,水体、土壤和泉沉积物中HCHs主要源于林丹的使用;水体中DDTs主要源于历史残留,而土壤和泉沉积物中DDTs主要来源于近期使用。相关性分析结果表明,HCHs和DDTs可从补给区地表水和补给区土壤分别向排泄区泉水和泉沉积物中迁移。HCHs和DDTs在介质中的快速迁移证实了岩溶区地下水的脆弱性。本研究成果可以为岩溶地下水资源和环境的保护提供参考。

土耳其岩溶地质概况

土耳其岩溶分布面积约占其国土面积的40%,发育典型的地中海气候类型岩溶,根据构造特征,从北向南分为四个不同的岩溶区,其中托罗斯山脉是土耳其乃至地中海地区最大、最为发育的岩溶区,具有很高的研究价值。文章在系统收集地质、构造及水文地质等资料基础上,编制1∶100万土耳其岩溶地质图,分析了影响岩溶发育的因素,总结了土耳其岩溶分布规律、主要岩溶现象及资源开发利用现状,为“全球岩溶地质”数据库建设和服务全球岩溶大科学计划提供支撑。

泰山北翼岩溶含水介质分布及地下水循环规律研究

为了深入认识济南岩溶泉水及地热水循环过程,本文以泰山北翼碳酸盐岩含水介质空间分布特征为研究出发点,分析其埋藏条件和连续性特征,并利用数理统计、空间插值、Piper三线图、概念模型等方法,结合水动力场、水化学场、水温度场和水年龄场“四场”分析,揭示区域地下水循环规律。结果表明:地表分水岭与齐广断裂、禹王山断裂、聊考断裂等深大断裂控制了泰山北翼地区岩溶含水介质空间展布,大致呈现由南向北埋藏深度逐渐增大的变化趋势,受马山断裂、东坞断裂、文祖断裂等次级断裂影响岩溶含水介质上下盘有不同错动,但东西展布仍具有较好连续性;区域地下水循环过程极其复杂,泰山岩群、寒武纪及奥陶纪各类含水岩组通过排泄-渗漏、断裂垂向径流、水平地下径流等形式发生水流交汇,并在山前局部地区与第四纪松散孔隙水产生水量交换,最终通过泉或人工开采形式排泄。区域地下水流具有统一的“四场”,并且呈现明显的水平与垂向分带特征,大致沿东阿断裂及其延长线—吴家堡—华山—章丘区—淄博磁村一线划分冷泉与地热水的分界线,以600 m、1000 m划分出浅、中、深循环深度分界线;冷泉以浅循环为主,中、深循环为辅,地下水矿化度、温度、年龄偏低,而地热水以中、深循环为主,浅循环为辅,地下水矿化度、温度、年龄偏大。不同含水介质水流具有一定内在关联,构成一个完整的岩溶水系统。