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1.
Multi-tracer investigation of groundwater residence time in a karstic aquifer: Bitter Lakes National Wildlife Refuge, New Mexico, USA 总被引：1，自引：1，他引：0
Several natural and anthropogenic tracers have been used to evaluate groundwater residence time within a karstic limestone aquifer in southeastern New Mexico, USA. Natural groundwater discharge occurs in the lower Pecos Valley from a region of karst springs, wetlands and sinkhole lakes at Bitter Lakes National Wildlife Refuge, on the northeast margin of the Roswell Artesian Basin. The springs and sinkholes are formed in gypsum bedrock that serves as a leaky confining unit for an artesian aquifer in the underlying San Andres limestone. Because wetlands on the Refuge provide habitat for threatened and endangered species, there is concern about the potential for contamination by anthropogenic activity in the aquifer recharge area. Estimates of the time required for groundwater to travel through the artesian aquifer vary widely because of uncertainties regarding karst conduit flow. A better understanding of groundwater residence time is required to make informed decisions about management of water resources and wildlife habitat at Bitter Lakes. Results indicate that the artesian aquifer contains a significant component of water recharged within the last 10–50 years, combined with pre-modern groundwater originating from deeper underlying aquifers, some of which may be indirectly sourced from the high Sacramento Mountains to the west. 相似文献
2.
Well-developed karst aquifers tend to be heterogeneous and consist of variable porosities. Groundwater monitoring and the
associated data interpretations in such aquifers are often more complicated than porous medium aquifers. Collection of representative
data in karst aquifers often requires monitoring at appropriately located wells and/or springs that are proven to connect
to the groundwater system. Water samples are to be collected under different flow conditions, including base flow, high-flow,
and low-flow. The sampling frequencies may vary from several months for base flows to minutes in response to recharge events.
The groundwater monitoring program presented in this paper is for a cement kiln dust mono-fill site in a karst area of southern
Indiana. Following dye tracing and extensive geophysical investigations, one spring was selected as a monitoring location.
A second spring should be used as a monitoring location when the last cell of the mono-fill begins receiving the wastes. The
paper discusses results from the first spring, at which nine background sampling events were completed to evaluate the natural
variations of the water quality. Based on the background data, a statistical evaluation plan was developed for 12 water-quality
parameters to determine the integrity of the landfill. The statistical power of the statistical analyses was evaluated by
Monte Carlo simulations. 相似文献
3.
The present groundwater monitoring network in Bavaria consists mostly of wells and only a small number of natural groundwater
springs, all of which are analyzed for mainly the common physical and chemical constituents in groundwater. In order to develop
a long-term groundwater management plan for all the groundwater resources of Bavaria, the Bavarian State Office for Water
Management intends to establish a separate spring-monitoring network throughout the 11 groundwater provinces of the state.
As a first step, significant physicochemical parameters that show considerable annual fluctuation (after monitoring 1–3 years)
were determined at 21 springs or spring systems to create a basic data set to guide future monitoring. A selection procedure
was developed around four parameters: (1) geological units, which includes the principal aquifers; (2) rate of spring discharge;
(3) land utilization within a catchment; and (4) approximate size of the subterranean catchment. However, in the initial phase
of the study, only the first three parameters were investigated. These parameters established a matrix for evaluating each
groundwater region of Bavaria to aid in the selection of additional springs for the proposed monitoring network.
Electronic Publication 相似文献
4.
40 多年来,我国西北地区大规模的地下水开发利用造成了部分地区地下水水位持续下降甚至泉水干涸,部分地区地下水仍能维持动态稳定,判断这类地区水资源开发利用是否具有可持续性是必须解决的重大科学问题。以黑河流域中游盆地作为研究对象,采用MK检验和连续小波分析等方法,分析长时间序列地下水水位数据的变化特点,研究区域地下水动态特征;结合区域水文地质条件,综合划分黑河流域中游盆地地下水补排平衡区与非平衡区;利用克里金插值法估算1990—2020 年盆地含水层对水资源的调节水量,并评价不同动态平衡区的调蓄能力。结果显示,黑河流域中游盆地地下水水位动态类型有:水文型、水文-开采型、开采型和蒸发-开采型4种长周期动态稳定型,过量开采型或上游过度引用地表水型2 种长周期持续下降型。黑河-梨园河倾斜平原、酒泉盆地和黑河中游下段侵蚀堆积平原的大厚度含水层是黑河流域中游盆地的地下水补排平衡区,其在1990—2001 年共输出地下水12.06×108 m3,2001—2020年共储存地下水9.06×108 m3。大厚度含水层为地下水的长周期调蓄提供了充足的空间,在合理控制开采量的前提下,该类含水层的天然调蓄能力可满足生产生活和下游生态用水需要。盆地地下水补排非平衡区,如黑河以东诸河倾斜平原、盐池盆地和榆木山山前诸小河流域等地区,目前的地下水开发利用方式和强度是不可持续的,应适当减少地下水开采量,调节盆地上游的引水量和开采量,抑制地下水资源枯竭。本研究成果可为西北干旱内陆地区水资源管理和持续开发利用提供参考。 相似文献
5.
Management of freshwater lenses on small Pacific islands 总被引：3，自引：0，他引：3
The nature of shallow aquifers and the impacts of seawater intrusion in small islands within the Pacific Ocean are reviewed. Many Pacific islands rely on shallow fresh groundwater lenses in highly permeable aquifers, underlain and surrounded by seawater, as their principal freshwater source. It is argued here that, in small islands, the nature of fresh groundwater lenses and their host aquifers coupled with frequent natural and ever-present anthropogenic threats make them some of the most vulnerable aquifer systems in the world. A simple steady-state approximation is used to provide insight into the key climatic, hydrogeological, physiographic, and management factors that influence the quantity of, and saline intrusion into freshwater lenses. Examples of the dynamic nature of freshwater lenses as they respond to these drivers are given. Natural and human-related threats to freshwater lenses are discussed. Long dry periods strongly coupled to sea surface temperatures impact on the quantity and salinity of fresh groundwater. The vulnerability of small island freshwater lenses dictates careful assessment, vigilant monitoring, appropriate development, and astute management. Strategies to aid future groundwater sustainability in small islands are presented and suggested improvements to donor and aid programs in water are also advanced. 相似文献
6.
Assessment and mapping of the intrinsic vulnerability to pollution: an example from Keritis River Basin (Northwestern crete, Greece) 总被引：1，自引：1，他引：0
Due to the geological and hydrogeological characteristics, the carbonate aquifers are frequently vulnerable to natural and/or anthropogenic polluting sources. The aim of the present study is to evaluate the intrinsic vulnerability to pollution of the Keritis River Basin (northwestern Crete, Greece). The huge amount of the flowing groundwater represents a strategic water resource to be allocated to drinking water purpose and to agricultural activities, too. The studied groundwater are characterized by quality degradation processes represented by the anthropogenic and natural pollution such as olive oil farming, agriculture activities, industrial waste and salt water intrusion. For a better management and protection of the water resources, the assessment and mapping of groundwater vulnerability to pollution are very important. From this investigation, the Keritis Basin showed an intrinsic vulnerability degree from extremely high to very low. This study allows to define the strategies which will permit a proper safeguard criteria, against the pollution sources of the Keritis Basin groundwater resources. 相似文献
7.
《Applied Geochemistry》2005,20(11):2063-2081
This paper deals with chemical and isotope analyses of 21 springs, which were monitored 3 times in the course of 2001; the monitoring program was focused on the groundwater of the Gran Sasso carbonate karst aquifer (Central Italy), typical of the mountainous Mediterranean area.Based on the hydrogeological setting of the study area, 6 groups of springs with different groundwater circulation patterns were distinguished. The hydrogeochemistry of their main components provided additional information about groundwater flowpaths, confirming the proposed classification. The spatial distribution of their ion concentrations validated the assumptions underlying the hydrogeological conceptual model, showing diverging groundwater flowpaths from the core to the boundaries of the aquifer. Geochemical modelling and saturation index computation elucidated water–carbonate rock interaction, contribution by alluvial aquifers at the karst aquifer boundaries, as well as impacts of human activities.The analysis of 18O/16O and 2H/H values and their spatial distribution in the aquifer substantiated the hydrogeology-based classification of 6 groups of springs, making it possible to trace back groundwater recharge areas based on mean isotope elevations; the latter were calculated by using two rain monitoring stations. 87Sr/86Sr analyses showed seasonal changes in many springs: in winter–spring, the changes are due to inflow of new recharge water, infiltrating into younger rocks and thus increasing 87Sr/86Sr values; in summer–autumn, when there is no recharge and spring discharge declines, changes are due to base flow groundwater circulating in more ancient rocks, with a subsequent drop in 87Sr/86Sr values.The results of this study stress the contribution that spatio-temporal isotope monitoring can give to the definition of groundwater flowpaths and hydrodynamics in fissured and karst aquifers, taking into account their hydrogeological and hydrogeochemical setting. 相似文献
8.
Some of the world’s deepest goldmines are located in the Far West Rand (FWR) goldfield operating below of up to 1.2-km-thick dolomites hosting some of the largest karst aquifers in South Africa. Associated impacts include the dewatering of the overlying karst aquifers as well as linking previously disconnected compartments by mining through aquicludes (dykes). The focus of the study is on predicting groundwater balances in re-watered aquifers after mining ceases as this will determine whether or not associated karst springs that dried-up due to dewatering will ever flow again. Critically revisiting, Swart et al. (Environ Geol 44:751–770, 2003a) who predict that all springs will flow again, this study uses significantly larger data sets and modified assumptions to increase the robustness of findings as the question is crucial for post-closure development. As a first of two papers, this part develops a conceptual model on the mega-compartment concept that predicts a flat water table across all linked compartments that would leave the springs dry. The model identifies the ratio between inflowing surface water (recharge) and underground water losses to downstream compartments via mined-through dykes (‘inter-compartmental groundwater flow’, IGF) as a key factor governing the elevation of the post-mining water table, creating the base for part 2, where the IGF and the post-mining water tables are determined using unique large data sets that have not been evaluated before. 相似文献
9.
Groundwater monitoring in the Polish-Lithuanian cross-border area was launched in 1994, utilizing 24 monitoring stations. Of these, 20 are installed in aquifers in Quaternary tills, which are the main source of fresh water for centralized use and single households. Hydro-chemical sampling has been performed twice a year (spring and autumn) over a seven-year period, with determination of main chemical compounds. Hydrochemical differences on both sides of the border appear to be related to the type of land use. The groundwater quality on the Lithuanian side may have been influenced by anthropogenic factors operating prior to 1991 in the Soviet-type collective farms. The main trends over the monitoring period involve increase in SO42+and Cl- ions on both sides of the border. The data demonstrate the importance of cross-border monitoring and exemplify groundwater chemistry as a direct geoindicator of the state of the environment. 相似文献
10.
金沙江河谷巧家段地下水化学特征 总被引：1，自引：0，他引：1
金沙江河谷巧家段地形切割强烈,最大相对高差可达2 719 m,水文地质条件差异大,河谷区内泉水出露众多。对河谷区内38组泉水水化学组分进行分析的结果表明:地下水化学类型较简单,主要为HCO3- Ca、HCO3- Ca?Mg、HCO3- Mg?Ca型;地下水溶解性总固体(TDS)浓度变化较大,总体上TDS浓度自河谷斜坡补给-径流区至谷底排泄区,具有逐步增高的趋势;孔隙水TDS浓度明显高于岩溶水;地下水宏量组分HCO3-、Ca2+、Mg2+、SO42-与TDS具有正相关关系。据水化学组分变化分析谷底第四系地层中出露大泉的形成条件,其为孔隙水与岩溶水相混合形成。 相似文献
11.
N. S. Magesh N. Chandrasekar L. Elango 《Journal of the Geological Society of India》2018,92(5):634-644
Abstraction of groundwater resources is increasing over the years to meet its ever-increasing demand for industrial, agricultural and domestic purposes throughout the world. The scenario is even worse in the east flowing rivers of the Western Ghats, where the demand of water is high under changing climatic conditions. Such situation may affect the groundwater resources of the river basin on a long run. The aim of the present study is to characterize the geochemistry of groundwater in Tamiraparani sub-basin through geochemical modeling and deduce the ionic interactions with the aid of geostatistical and multivariate statistical techniques. A total of 40 groundwater samples from shallow aquifers were collected randomly throughout the sub-basin for assessing its physicochemical parameters, which include physical properties of the water, major ions and nutrients. Two major hydrogeochemical facies were identified such as mixed Ca-Mg-Cl and Ca-HCO3 groups. The nutrients derived from agricultural runoff, urban discharge and organic decomposition alters the nutrient level in the groundwater. The dissolution/precipitation of minerals such as calcite and dolomite controls the chemical constituents of the groundwater. The multivariate statistical analysis indicates that natural weathering of source rocks is the main contributors of ions in the groundwater followed by anthropogenic activities such as agricultural practices and urbanization. The insights obtained from this study can be helpful for sustainable groundwater management and long-term monitoring studies. 相似文献
12.
Gropius M. Dahabiyeh M. Al Hyari M. Brückner F. Lindenmaier F. Vassolo S. 《Hydrogeology Journal》2022,30(6):1769-1787
Jordan suffers from water scarcity and groundwater covers the majority of Jordan’s water supply. Therefore, there is an urgent need to manage this resource conscientiously. A regional numerical groundwater flow model, developed as part of a decision support system for the country of Jordan, allows for quantification of the overexploitation of groundwater resources and enables determination of the extent of unrecorded agricultural groundwater abstraction. Groundwater in Jordan is abstracted from three main aquifers partly separated by aquitards. With updated geological, structural, and hydrogeological data available in the country, a regional numerical groundwater flow model for the whole of Jordan and the southernmost part of Syria was developed using MODFLOW. It was first calibrated for a steady-state condition using data from the 1960s, when groundwater abstraction was negligible. After transient calibration using groundwater level measurements from all aquifers, model results reproduce the large groundwater-level declines experienced in the last decades, which have led to the drying out of numerous springs. They show a reversal of groundwater flow directions in some regions, due to over-abstraction, and demonstrate that documented abstractions are not sufficient to cause the observed groundwater-level decline. Only after considering irrigation water demand derived from remote sensing data, the model is able to simulate these declines. Illegal abstractions can be quantified and predictive scenarios show the potential impact of different management strategies on future groundwater resources.
相似文献13.
Groundwater flow systems in turbidites of the Northern Apennines (Italy): natural discharge and high speed railway tunnel drainage 总被引：2，自引：0，他引：2
Alessandro Gargini Valentina Vincenzi Leonardo Piccinini Gian Maria Zuppi Paolo Canuti 《Hydrogeology Journal》2008,16(8):1577-1599
Turbidites crop out extensively in the Northern Apennine mountains (Italy). The huge amounts of groundwater drained by tunnels, built for the high speed railway connection between Bologna and Florence, demonstrate the aquifer-like behaviour of these units, up to now considered as aquitards. A conceptual model of groundwater flow systems (GFS) in fractured aquifers of turbidites is proposed, taking into account both system natural state and the perturbation induced by tunnel drainage. Analysis of hydrological data (springs, streams and tunnel discharge), collected over 10 years, was integrated with analysis of hydrochemical and isotopic data and a stream-tunnel tracer test. Hydrologic recession analysis of undisturbed conditions is a key tool in studying turbiditic aquifer hydrogeology, permitting the discrimination of GFS, the estimation of recharge relative to the upstream reach portion and the identification of springs most vulnerable to tunnel drainage impacts. The groundwater budgeting analysis provides evidence that the natural aquifer discharge was stream-focused through GFS, developed downslope or connected to main extensional tectonic lineaments intersecting stream beds; now tunnels drain mainly active recharge groundwater and so cause a relevant stream baseflow deplenishment (approximately two-thirds of the natural value), possibly resulting in adverse effects on local ecosystems. 相似文献
14.
The impact of groundwater withdrawals on the interaction between multi-layered aquifers with different water qualities in the Viterbo geothermal area (central Italy) was studied. In this area, deep thermal waters are used to supply thermal spas and public pools. A shallow overlying aquifer carries cold and fresh water, used for irrigation and the local drinking-water supply. Starting with a conceptual hydrogeological model, two simplified numerical models were implemented: a steady-state flow model of the entire groundwater system, and a steady-state flow and heat transport model of a representative area, which included complex interactions between the aquifers. The impact of increased withdrawals associated with potential future development of the thermal aquifer must be considered in terms of the water temperature of the existing thermal sources. However, withdrawals from the shallow aquifer might also influence the discharge of thermal sources and quality of the water withdrawn from the shallow wells. The exploitation of the two aquifers is dependent on the hydraulic conductivity and thickness of the intervening aquitard, which maintains the delicate hydrogeological equilibrium. Effective methods to control this equilibrium include monitoring the vertical gradient between the two aquifers and the residual discharge of natural thermal springs. 相似文献
15.
The Nebrodi Park, located in the north-eastern sector of Sicily, is of particular environmental and scientific interest.
This is due to the morphological heterogeneity of the protected region that presents a wide variety of landscapes and ecosystems.
In spite of the recent efforts of the Regional Government and Municipalities, environmental resources, especially groundwater,
risk progressive depauperation and pollution. In this paper, the authors consider the hydrogeological karst unit of Monte
Traura-Rocche del Crasto, the most productive in the Nebrodi belt (zone B of the regional park). This unit is underexploited
and needs a careful hydrogeological study in order to supply coastal aquifers. Geochemical and geophysical prospecting has
been carried out in this area. Analyses of water springs, sampled in different seasons, have suggested patterns of groundwater
circulation. Apparent resistivity measurements have yielded complementary information about the recharge processes of deep
aquifers. Goals of the project to which this research belongs are the rational exploitation and protection of reservoirs such
as Monte Traura and the recovery of the degraded aquifers, proposing new strategies of regional management for the water resources
in this comer of Sicily.
Received: 27 November 1996 · Accepted: 5 January 1998 相似文献
16.
Noureddıne Guezgouz Djamel Boutoutaou Houarı Zeggane Azzedıne Chefrour 《Arabian Journal of Geosciences》2017,10(15):336
Water resources in Algeria are mainly controlled by climate change which creates enormous problems in its planning, management and distribution. While the surface water resources are perfectly managed and operated by means of dams and small dams built for several years, the groundwater resources remain long unknown and unusable because of the lack of relevant working tools (e.g., methods, formulas, maps, etc.) for planners and engineers working in the field of water resources exploration. To highlight the hydrodynamic processes of groundwater in shallow aquifers of the basins of northern Algeria, we conducted a study using 81 subwatersheds collected from different locations at the basins; taking into account the climatic and geomorphological factors, to understand water usage trends, analyse patterns, tap good shallow aquifers and ensure long lasting supplies of water through arid periods, mapping and modelling of groundwater are fundamental to problem resolution. Multivariate statistical techniques as well as cluster and principal component analysis were applied to the data on groundwater flow, with the objective of defining the main controls on the groundwater flows at the basins. These statistical techniques showed the presence of three groundwater flow groups with increasing importance according to precipitation. The first group was mainly influenced by climatic factors, the second was more controlled by the communication between the surface and underground flows and the third group revealed the influence of geomorphological factors on groundwater flows. 相似文献
17.
Geologic and geochemical variations across a 4200 km2 area of south-central Wisconsin (USA) were used to examine their relationship to phosphorus concentrations in groundwater from more than four hundred private water supply wells. Surficial geology in the study area ranged from Cambrian sandstones to Ordovician dolomites. Groundwater phosphorus concentrations were higher in aquifers of older Cambrian age compared to the concentrations in aquifers of younger Cambrian and Ordovician age. Because iron concentrations were relatively low in these waters and agricultural land use was similar in all geologic regions, we propose that the differences in bedrock phosphorus and anthropogenic geochemical impacts explain the differences in phosphorus concentrations between aquifers. Within the older Cambrian aquifers, groundwater phosphorus concentrations were elevated in groundwater with higher nitrate-nitrogen concentrations. This finding is consistent with the presence of phosphorus within sediment in these strata and geologic conditions that weakly buffered pH reduction from anthropogenic acidification. In contrast, groundwater phosphorus concentrations in younger Cambrian and Ordovician aquifers were not elevated in samples with higher nitrate. Anthropogenic acidification in these carbonate-rich aquifers was neutralized through increased carbonate weathering, which led to higher groundwater calcium and alkalinity and would limit the dissolution of phosphate-rich minerals, such as apatite, where present. Low iron concentrations observed in most samples suggest that the phosphorus release in the Cambrian strata occurs beyond the zone of secondary mineral retention in the soil. These results have important implications for the eutrophication of inland surface waters in areas with bedrock phosphorus and anthropogenic acidity that is not neutralized before it contacts phosphatic rock. 相似文献
18.
H. Elhatip 《Environmental Geology》1997,31(1-2):27-33
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
19.
Kuo-Chin Hsu Hsin-Fu Yeh You-Cheng Chen Cheng-Haw Lee Chung-Ho Wang Feng-Sheng Chiu 《Hydrogeology Journal》2012,20(3):499-517
The sustainable use of groundwater has become increasingly challenging due to extreme hydrological events and anthropogenic activity. In this study, the basin-scale groundwater response to precipitation variation was analyzed using an integrated model that comprises lumped models for land and river recharges and a distributed model for groundwater. The integrated model was applied to the Chih-Ben watershed, Taiwan, using 20?years (1988?C2007) of data. The hydrological data were analyzed for trends using statistical tests. Based on decreasing trends in precipitation and groundwater levels and an increasing trend in stream flow, the oblique-cut method was applied to precipitation and excess infiltration to assess land and streambed recharge. Distributed numerical groundwater modeling was used to simulate the basin-scale groundwater responses to precipitation variation and anthropogenic pumping. The model was calibrated using stable-isotope and groundwater-level data. The safe yields were estimated for the Chih-Ben watershed for dry, wet, and normal precipitation scenarios. The safe yield of groundwater was shown to vary with precipitation, which does not guarantee the sustainable use of groundwater resources. Instead, water resources should be assessed at a basin scale, taking into account the whole ecosystem, rather than only considering water for human consumption in the alluvium. 相似文献
20.
从黑河流域地下水年龄论其资源属性 总被引：16，自引：1，他引：16
地下水资源的可持续性是当前干旱区流域水资源管理的首要问题之一 ,我国西北内陆干旱区地下水的可持续开发必须首先要了解地下水系统的更新能力 ,地下水的放射性同位素测年可以提供系统循环时间和更新能力的重要信息。本文利用地下水中放射性氚 (3H )和碳 (1 4C)测年方法 ,计算黑河流域地下水的年龄 ,进而讨论地下水的更新性。结果表明 :潜水年龄多数小于 5 0 a,具有可再生的资源的属性 ,其中山前戈壁带和张掖盆地细土平原潜水地下水年龄小于 4 0 a,为 196 3年以来补给。酒泉东盆地排泄区承压含水层中地下水的年龄为 2 338～5 5 6 9a,额济纳附近的深层承压含水层中 ,地下水的年龄为 5 4 86～ 86 30 a,地下水资源更新性较差。但是张掖盆地河流附近深层承压地下水年龄小于 5 0 a,具有一定的更新性。上述认识不仅对黑河流域水资源管理和生态环境建设具有重要意义 ,而且对西北类似的内流盆地的地下水系统的研究有着借鉴意义 相似文献