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1.
The influence of karst features on environmental studies in Turkey   总被引:5,自引:0,他引:5  
 The carbonate rocks of Turkey, which underlie about one third of the country, possess major water resources with great potential for electricity generation and water supplies. The ongoing development of karst features, especially in the southern part of Turkey, demonstrates specific environmental problems that occur in many karst water supply projects. Karst aquifers, springs, sinkholes, dolines, poljes and other karst features are of great importance from the standpoint of karst water resources and environmental research studies. In karst regions, conservation and protection of groundwater resources for both qualitative and quantitative evaluations is possible only when the catchment area is determined accurately. Since the catchment area in karst terrains is not limited by the surface drainage boundaries and the groundwater flows through well-developed coduits or fissures, the equations used in non-karstic areas cannot be applied to such karstic regions. Studies on the development of karst features and its environmental impacts in Turkey are of recent origin. Therefore, many unreliable methods are being applied in karstic areas. For example, the use of "shallow holes or sinkholes and fault zones" for septic water waste disposal or as sewage by those who are not familiar with karst, sometimes causes very serious problems of extensive groundwater pollution. This paper discusses the development of different karstic features in Turkey and case studies on its environmental impacts. Received: 27 December 1995 · Accepted: 10 July 1996  相似文献   

2.
KARSTIC: a sensitivity method for carbonate aquifers in karst terrain   总被引:5,自引:2,他引:5  
. Groundwater in karstic aquifers can be dangerously sensitive to contamination. Many cities in the western USA rely on karstic carbonate aquifers for municipal water supplies. For example, Rapid City, South Dakota, pumps more than half of its drinking water from wells in the Madison Limestone. This work examined the sensitivity of karstic aquifers to surface contamination in mountainous terrain. Where karstic carbonate aquifers are exposed at their outcrop areas, they are particularly susceptible to the introduction of contamination through diffuse recharge or through point recharge at swallow holes along streams. Residential developments in mountainous regions of the western USA are encroaching on the recharge areas of karstic aquifers. Many of these residential developments are served by onsite wastewater disposal systems such as septic tanks and drain fields, with the attendant danger of introduction of pathogens from malfunctioning treatment systems above fractured limestone which offers little filtering. Where streams disappear into karstic aquifers at swallow holes, microbial contaminants such as Giardia or Cryptosporidium are a concern, as well as potential spills, leaks, or accidents along roads near these streams. The KARSTIC method developed and modified in this work puts greater emphasis on karst features than previous sensitivity procedures such as the US Environmental Protection Agency's DRASTIC method. The modified method gives increased attention to highly sensitive areas of karstic carbonate aquifers by weighting the synergistic effects of fracturing, karst development, and swallow holes of recharging streams. In a field application, hydrogeologic maps of a watershed in the Black Hills, USA, were digitized into a geographic information system. The resulting sensitivity map and report can be used by planners, managers, and the public as a screening tool for assessing groundwater sensitivity in regions which include karstic aquifers.  相似文献   

3.
Greece is dependent on groundwater resources for its water supply. The main aquifers are within carbonate rocks (karstic aquifers) and coarse grained Neogene and Quaternary deposits (porous aquifers). The use of groundwater resources has become particularly intensive in coastal areas during the last decades with the intense urbanization, tourist development and irrigated land expansion. Sources of groundwater pollution are the seawater intrusion due to over-exploitation of coastal aquifers, the fertilizers from agricultural activities and the disposal of untreated wastewater in torrents or in old pumping wells. In the last decades the total abstractions from coastal aquifers exceed the natural recharge; so the aquifer systems are not used safely. Over-exploitation causes a negative water balance, triggering seawater intrusion. Seawater intrusion phenomena are recorded in coastal aquifer systems. Nitrate pollution is the second major source of groundwater degradation in many areas in Greece. The high levels of nitrate are probably the result of over-fertilization and the lack of sewage systems in some urban areas.  相似文献   

4.
《Geodinamica Acta》2013,26(1-3):89-100
The study presents natural hazards in Slovenia's karst, focusing on flooding in karst poljes. A specific study was done on the flood dynamics of two typical and connected karst poljes (Cerknica and Planina) of the Classical Karst region. In the case of particularly extreme hydrological conditions in the autumn of 2008, detailed analyses of the recharge-discharge regime and the interrelationship of flooding on the two poljes were done. Daily precipitation, discharge, and water level values from several monitoring sites were analyzed and cross-correlated, and additional hydrological analyses were done using a digital elevation model in order to acquire water level increase and decrease intensity, flood water volumes, and the extent of flooding and to understand the conditions controlling karst flooding. The results reveal that the hydrological functioning of the studied karst poljes is influenced by the hydrogeological and temporary hydrological conditions in the catchment area. The response of the binary karst system (i.e., the influence of autogenic and allogenic recharge) is especially distinct. The study shows that during extremely intense recharge, the reactions of karst aquifer systems to precipitation are as rapid as the response of surface waters (the water level of Cerknica Lake increased with an intensity of 38-63 cm/day or 55 m3/s respectively) while retention capacities are negligible. In contrast to flash floods, floods in karst areas may last from several weeks to several months. For the observed period a three-dimensional simulation of the flooding was made. At the maximum recorded water level, the volume of water on the Cerknica polje was 51 million m3, and 26 million m3 on the Planina polje. The maximum extent of flooding on the Cerknica polje was 23 km2 and on the Planina polje 9.5 km2. On the basis of the study, information was provided regarding future hazard mitigation. However, the study demonstrated that a sufficiently dense monitoring network is necessary to predict the occurrence and duration of floods with greater certainty.  相似文献   

5.
It is widely recognized that karstification can substantially influence flow and transport characteristics in carbonate aquifers. Surface features such as sinkholes are widely used to diagnose the presence of a karst aquifer, but specific borehole tests for karst have not been well defined. Such tests are especially important in glaciated areas where karst features have been eroded or buried by till. One such area is Smithville, Ontario, where more than 60 boreholes at a PCB-contaminated dolostone site provided an opportunity for a wide range of downhole tests and monitoring to be carried out. It was found that there were a number of useful tests for indicating karstification. These included (1) the order of magnitude differences between pump, slug and packer test results, (2) the presence of water table troughs, (3) rapid water level response following recharge events, (4) the rapid changes in water quality following recharge events, (5) water undersaturated with respect to calcite following recharge events, and (6) a wide range in fracture apertures along major bedding planes. Most parameters vary over a similar range at Smithville as they do at Mammoth Cave, Kentucky, indicating that the Smithville aquifer behaves as a typical karst aquifer.  相似文献   

6.
忻州盆地边山岩溶水与盆地孔隙水存在密切的水力联系,岩溶水系统的圈划与分析对盆地孔隙水资源评价十分重要。文章运用地下水系统分析理论,基于地理信息系统技术,定量提取区域地质(岩相古地理、地层与构造)和水文地质信息,绘制了基于区域隔水底板等高线图、典型剖面图、盆地-山区两壁投影图等信息的岩溶水系统图;运用岩溶水系统图分析得出下马圈泉岩溶水系统与盆地孔隙水存在间接汇水、潜流和河流(泉)渗漏等补给关系,并给出了补给量的计算方法,为忻州盆地地下水资源评价与定量模拟提供了新的水文地质依据与基础。  相似文献   

7.
生态系统变化对湘西岩溶水资源的影响   总被引:3,自引:0,他引:3  
本文在分析岩溶山区典型生态系统类型及其演化特征和岩溶水资源特点的基础上,通过湘西20年来的生态系统变化的对比,就其对岩溶水资源的影响进行了详细的论述。认为生态的恶化是引起岩溶石山区水资源短缺的一个重要因素,生态系统变化对岩溶水资源的影响主要是通过对岩溶水的补给、迳流、排泄等的影响,使岩溶水资源产生水质和水量的变化。明确生态系统变化是如何影响岩溶水资源的质与量这一重大问题,将有助于岩溶水循环机制的深入研究,为揭示岩溶水资源的形成、演化规律及控制机理,建立岩溶水资源评价、开发利用和保护的系统理论,探索岩溶水资源可持续利用模式提供科学的依据。  相似文献   

8.
Dinarides南部是世界上岩溶发育最强烈的地区之一,同时也是欧洲降水量最大的地区。区内碳酸盐岩沉积厚度大于300m,平均岩溶发育深度从250m 至350m,沿断裂发育的岩溶,甚至更深。地下水平均流速变化较大,从0.002 cm/s至55.2cm/s。地下水滞留时间很短,水位变化非常迅速,变幅高达312m。地下水位对强降雨的响应小于4小时。岩溶大泉的主要特征是管道出口深,最大最小流量变化大。区内发育的落水洞有成千上百个,其中一些落水洞排水能力超过100m3/s,规模巨大并被洪水暂时淹没的岩溶坡立谷闻名世界各地。泉水天然流量和野生动物生存环境的改变,特别是当地特有物种的破坏,已经成为新近许多岩溶工程项目的焦点议题。由于该区极其复杂的水文地理和政治环境,不同国度间的跨界含水层似乎是一个非常敏感的问题。   相似文献   

9.
This study used optical brighteners (OB) released from septic systems to show that groundwater flow direction is largely controlled by the structural framework in a faulted karst groundwater system. Effective protection of groundwater resources requires that groundwater systems are adequately characterized and source water protection areas (SWPA) are developed for drinking water wells. Karst aquifers are among the most sensitive to contamination due to high recharge rates, and among the most difficult aquifers to characterize due to heterogeneity, and anisotropy. Because septic systems may be used to treat wastewater within SWPAs for karst aquifers there is a need to characterize these groundwater systems using tracers. The objective of this study was to characterize groundwater flow in a faulted portion of the Edwards aquifer in Bexar County, Texas using OB that are released as incidental tracers from septic systems. This study included measurement of water levels, sampling of groundwater and surface water, analysis for OB, and spatial analysis in a GIS. Results show that OB intensities were highest to the southwest of the septic area, a direction that is sub-parallel to the fault and fracture orientation and nearly perpendicular to the hydraulic gradient. This indicates that movement of OB, solutes, or non-aqueous liquids/solids in a faulted karst system can be largely controlled by fault/fracture orientation and structural relay ramps.  相似文献   

10.
Land application is the only currently available technique for sewage wastewater disposal along the Nile Valley in Upper Egypt. Wastewater disposal projects have been established in the lowland desert zone extending between the cultivated floodplain and the Eocene Limestone plateau. The plan is to use the treated wastewater in irrigating woody farmlands. Some wastewater disposal sites are already operating, and several others will be established in the near future. The proposed wastewater disposal sites are located in a sensitive desert zone that is extremely narrow and situated very close to vital resources including the cultivated floodplain, reclaimed lands, residential areas, and surface water resources. In addition, the subsurface sediments of this zone (Pleistocene sand–gravel succession) constitute a significant part of the Quaternary aquifer of the valley. The objective of this study is to characterize and investigate the wastewater disposal sites and assess their probable environmental hazards. The study showed that the available lands are insufficient to accommodate the projected quantities of wastewater. At the currently operating sites, excess raw wastewater is accumulating on the ground surface forming large uncontrolled ponds. Such wastewater ponds represent a potential environmental hazard and might cause disastrous health effects, where chemical and bacteriological pollution of soil, crops and water resources may occur.  相似文献   

11.
龙涧泉岩溶水系统特征   总被引:2,自引:2,他引:0  
文章以地下水系统理论为指导,对龙涧泉岩溶水系统的边界条件、人工干预条件下地下水动力场演化特征等方面进行了系统的研究。根据区域地质、构造、地形地貌和水文地质条件,探究了龙涧泉岩溶水系统,圈定了系统的范围、边界性质、流动系统内部及其与外部系统之间的关系,确定龙涧泉为系统的唯一天然排泄口,龙涧泉岩溶水系统与白浪岩溶水系统无直接水力联系。龙涧泉岩溶水系统岩溶水补给来源主要是大气降水、河流入渗及侧向径流补给,现状条件下总补给量为864.42万m3/a,多年平均补给量为836.81万m3/a;排泄主要是水源地开采和矿山排水,现状开采量为4 117.2万m3/a。由于开采量大于允许开采量,并超过了总补给量,区内岩溶水一直处于超采状态。2004—2008年矿区岩溶水实测年均下降1.61 m/a,多年(1984—2008)水位平均降幅为5.68 m/a,最大降幅17.42 m/a。此外还讨论了岩溶水系统的补给、排泄条件,提出了龙涧泉岩溶水开发、保护、复泉与管理龙涧泉岩溶水系统的建议。   相似文献   

12.
李潇  漆继红  许模 《中国岩溶》2020,39(3):375-383
西南地区典型紧窄褶皱控制下的浅层岩溶水,具有循环交替快、水量丰富等特点。精细刻画小尺度浅层岩溶水系统模式类型及其特征,对于探讨岩溶水资源量以及中—浅埋隧道涌水条件具有重要意义。本文以西南典型紧窄褶皱——重庆铜锣山背斜和遵义铜锣井背斜为研究对象,细致地梳理岩溶水系统特征的控制性因素,提出地层空间结构的细微差异导致含水介质及地下水补给、径流、排泄特征等不尽相同。据此,将研究区浅层岩溶水系统细分为四类小尺度模式,并基于各模式差异分析中—浅埋隧道涌水条件。研究认为:穿越不同小尺度岩溶水系统的隧址段,其涌水条件具有一定差异;间互式地层空间结构导致小尺度浅层岩溶水系统之间因地表水体的转换而存在联系,计算涌水量时需考虑相邻可溶岩地层外源补给,而包裹式结构则造成各系统相对独立,计算时需考虑相邻非可溶岩地层外源补给;深切河谷排泄边界,不可忽略降雨对隙流散排型模式的补给,计算涌水量时,降雨量参数应小于年均降雨量,但若边界为浅切河谷,降雨量参数可直接选用年均降雨量。   相似文献   

13.
Methods exist to obtain “new sources of water.” Examples include: (1) capturing and enhancing stormwater recharge and retention within diffuse-flow portions of karst and other aquifers; (2) recycling and reuse of waste water; (3) reducing evapotranspiration and rejected recharge; and (4) ameliorating atmospheric acid deposition through use of alkaline groundwater. These little used management methods have immense potential to sustain future water demands. Full utilization of “new” and traditional water resources requires an understanding of the hydrogeologic framework of karstic aquifers. Reliable conceptual, numerical flow and transport models are needed to help evaluate, select, and design viable water management options. Three such simulation examples are provided together with a discussion of Penn State’s Wastewater reuse project where recharge approaches 3.785 × 109l/year  相似文献   

14.
济南市玉符河多水源回灌岩溶水水质风险评价   总被引:1,自引:1,他引:0  
济南以泉城而闻名,保泉和供水安全问题是其面临的巨大挑战,利用多水源进行岩溶水回灌是解决问题的有效措施之一,但是补给水源水质相对岩溶水而言较差,回灌到地下可能存在一定健康和环境风险,需要对回灌系统的水质进行风险评价。本文对比地下水质量标准和地下水水质背景值,重点选择地表源水超标和劣于背景值的风险源监测指标,借鉴澳大利亚含水层补给管理指南,对玉符河多水源回灌岩溶含水层工程运行期的水质风险进行评价。2015年对黄河水、卧虎山水库两种水源多次回灌期间的源水、孔隙水和岩溶水的22项指标进行水质监测和指标分析,风险残余评价结果表明黄河水回灌补源期间,平均浊度的标准指数源水是1.4,孔隙水1.7,岩溶水0.93,硫酸盐平均含量的标准指数源水是0.93,孔隙水0.9,岩溶水0.73,氯离子虽没有超过地下水III类标准,但是在源水中含量是地下水含量的2倍多;卧虎山水库水回灌补源期间,平均浊度的标准指数源水是2.4,孔隙水1.1,岩溶水0.43,硫酸盐平均含量的标准指数在源水0.75,孔隙水0.84,岩溶水0.66,氨氮的平均含量的标准指数源水1.14,孔隙水1.47,岩溶水1.35。因此,浊度、硫酸盐和溶质在裂隙岩溶含水层迁移较快为两种水源玉符河回灌补源工程的共同高风险项和关键控制点。此外,黄河水补源还需注意盐度,卧虎山水库水补源还需控制营养物的污染风险。基于以上评价,还提出了限制回灌量占区域岩溶水资源量比例等建议。   相似文献   

15.
Proper management of karst aquifers requires a better understanding of flow and transport mechanisms in these systems. Flow in karst aquifers is inherently very complex due to the non-linear and non-stationary relationship between recharge and discharge. Information on this relationship has been acquired for a large (1,000 km2), mountainous (>3,500 m asl) karst aquifer with a deep unsaturated zone (>2,000 m) in the Aladaglar mountain range of south-central Turkey. All major discharges from the aquifer, which drain almost all the recharge, have been observed periodically for specific electrical conductivity, tritium and oxygen-18 variations during a period of 12 months. Observations reveal that the system’s response to recharge depends strongly on the competition between the infiltration and drainage velocities. These velocities, which are controlled by variables such as the time of precipitation, time of infiltration, intensity, and continuity of recharge, determine the degree of dominance of different types of flow mechanisms in the aquifer. Bypass, well-mixed and piston flow mechanisms are used to explain the response of the aquifer to the spatio-temporal variations in recharge. It appears that the aquifer switches among these flow mechanisms depending on the prevailing recharge mode and the competition between infiltration and drainage velocities.  相似文献   

16.
桂江流域地下水污染途径及防控措施研究   总被引:1,自引:1,他引:0  
何愿  张颖  朱明 《中国岩溶》2015,34(4):387-394
对桂江流域开展岩溶地下水污染调查发现:流域内地下水污染源分为“三氮”污染源、重金属污染源、有机污染源三类;“三氮”污染源主要包括工业、养殖和生活三类污水、生活垃圾渗滤液、农业施用氮肥等;重金属污染主要来自工矿企业;有机污染来自工业、养殖业。污染途径主要有孤峰平原的分散入渗式、孤峰平原的脚洞灌入式、峰丛洼地的消水洞灌入式、溶丘谷地的入渗式和峰丛峰林谷地的天窗灌入式等五类。并对88组地下水样品测试结果进行多指标地下水污染综合评价,结果表明36.5%的水点为“三氮”污染,多以分散入渗进入地下水,其污染形态呈面状分布;15.3%的水点为重金属污染,主要通过峰丛洼地消水洞灌入式补给和溶丘谷地入渗补给两种途径,呈点状分布于污染场地附近;3.49%的水点为有机污染,主要为分散入渗补给途径,污染呈短线状或点状分布。   相似文献   

17.
大兴迭隆起隐伏岩溶水资源评价及开采方案预测   总被引:2,自引:2,他引:0  
大兴迭隆起地区隐伏岩溶地下水是北京市的重要水源,为保障水源地能持续为大兴、通州地区提供优质的城镇生活用水,需对研究区岩溶地下水进行水资源评价和开采规划预测分析。利用数值模拟法,应用GMS模拟软件对研究区岩溶水系统进行地下水流数值模拟及水位变化预测。建立的岩溶水系统模型分为5层,模拟验证期为12年9个月。由模型评价的岩溶水系统补给资源量为14 425.74×10^4m3/a,可开采资源量为14 310.52×10^4m3/a,其中岩溶含水层可开采量为2 309.36×10^4m3/a。在模型识别验证后,分4种开采方案对水源地进行开采预测,通过对典型观测孔水位过程线拟合和研究区水均衡分析可知,按2020年之前维持现状开采,2020年后停采念坛水源地,2025年后全区按可开采量进行开采的开采方案最为合理,可分批逐次实现水源地的采补平衡。  相似文献   

18.
Karst aquifer studies often focus on allogenic water inputs and large conduit flow. However, diffuse recharge can be significant, particularly in unconfined eogenetic karst aquifers that retain high matrix permeability. This study examines an unconfined region of the upper Floridan aquifer (USA) that hosts a sinking stream, its resurgence, and a large conduit system. Daily diffuse recharge was approximated using a water-budget method and ranged from 17% of precipitation during a low precipitation year to >53% during the highest precipitation year, illustrating the highly variable nature of diffuse recharge in this region. The total allogenic input via the sinking stream over the 5 years of the study was significantly larger than the volume of diffuse recharge. However, only about 2% of the allogenic recharge flows from the conduit into the surrounding aquifer. That flow is restricted to storm events when hydraulic heads in the conduits exceed those in the surrounding aquifer. The estimated volume of dissolution is similar for allogenic recharge and diffuse recharge to the unconfined region surrounding the conduits, but dissolution from the diffuse recharge is distributed over a larger area than dissolution from allogenic recharge. These results exemplify how recharge type impacts flow and water–rock interactions in eogenetic karst aquifers.  相似文献   

19.
岩溶区多重介质水流模型研究进展   总被引:9,自引:7,他引:2  
数值模拟技术广泛应用于地下水资源评价工作中,为水资源合理开发利用提供科学依据。本文针对岩溶区的数值模拟技术展开研究,综述了岩溶区地下水流建模技术的主要方法和研究进展,介绍了SWMM模型、UGRFLOW模型、CAVE模型、CFP模型等多重介质模型的建模方式和运行原理。岩溶区地下水赋存介质复杂,管道、裂隙和空隙多重介质并存,水流特征多样,等效连续介质模型不能很好地刻画岩溶区复杂的地下水流特征。随着对岩溶水流系统研究的深入,二重和三重介质模型逐渐应用于岩溶区地下水流模拟工作中,取得较好成果,但仍存在如忽略中宽裂隙的导水作用、岩溶管道设置单一、模型适用性不强等问题。今后应从解析岩溶含水介质的结构特征入手,关注中宽裂隙在地下水流系统中的导水作用和水流特征,改进管道流模块以更好地刻画复杂的地下河管道,改进不同介质间水流交换量算法,提高模型精确性和适用性。   相似文献   

20.
陇东盆地西部岩溶地下水形成机制研究   总被引:3,自引:1,他引:3       下载免费PDF全文
陇东盆地西部处于鄂尔多斯盆地西缘逆冲推覆构造带,新元古-下古生界碳酸盐岩裸露或浅埋,构成-南北向展布的岩溶水富集带。通过运用构造控水分析、水化学同位素等方法,对岩溶裂隙水系统进行了深入的分析与讨论。指出本区岩溶水的空间分布明显受南北向逆冲推覆构造控制,储水空间以岩溶裂隙为主,构造条件是岩溶发育和岩溶水富集的主要制约因素。岩溶水化学特征具有明显的南北差异,在补给条件优越的中南部平凉-华亭地区,水化学主要由含水层岩性及其赋存条件决定。岩溶地下水以大气降水来源为主,对于埋藏型岩溶水表现为多源水混合而成。根据岩溶水的空间分布与水动力场特征及其补径排条件,全区可划分为平凉、华亭和环西3个相对独立的岩溶水系统.并以此可作为水资源评价的基础。这些认识对于深入了解西北干旱-半干旱地区岩溶水赋存及富集规律、形成与演化机理和在该区开发利用岩溶地下水资源具有重要的科学意义。  相似文献   

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