Strategic ground water management for the reduction of karst land collapse hazard in Tangshan, China, 1997, Wang H. T. , Li Y. X. , Wang E. Z. , Zhao Z. Z. ,

Karst land collapse is a geological hazard caused mainly by human activities such as the pumping of ground water. The present study is aimed at determining a management strategy to minimize the risk of karst land collapse in the urban area of Tangshan, China. A method of groundwater management for multi-aquifer systems with groundwater confined and unconfined interchange properties has been developed. A groundwater simulation model and a management model are constructed for the studied area. The data used by the simulation and management models include the geometry of the aquifer systems, the parameters of hydrogeology, the distribution of recharge, and discharge in the simulation period and the historical water table elevations. The results of the model calculations show that the total balance between recharge and discharge for both Quaternary and bedrock aquifers is 4.7 x 106 m(3) in the period from November 1989 to October 1990. The optimal annual average pumping rate from the underlying bedrock aquifer is some 25.8 x 10(6) m(3), which is 54.4% of that which was pumped out of the aquifer in the hydrological year of 1990. If the management plan is carried out, the groundwater level in the bedrock aquifer will recover its confined state in most of the areas at risk of land collapse. This is the most resistant state to collapse in terms of groundwater flow.

The regional park of the Nebrodi Mts. (Sicily): a contribution to an integrated groundwater management, 1998, Cimino A, Abbate R, Martorana Tusa A,

Karst groundwater basin delineation, Fort Knox, Kentucky, 2002, Connair Dp, Murray Bs,

Evaluation of karst groundwater quality concern at Fort Knox Kentucky has required the development of a sitewide karst groundwater flow model and basin delineation investigation. The karst aquifer underlying Fort Knox is developed within approximately 60 m of the St. Louis Limestone and is bounded on three sides by surface streams that represent the local base level. The underlying Salem Limestone acts as a regional aquitard and provides a lower limit to karst aquifer development. The study area covers over 130 km(2) and contains over 200-inventoried karst features. As a part of this investigation, innovative multiple dye trace events were conducted throughout the study area using up to six dyes per event with a total of eight dyes used to conduct 14 dye traces during three seasonal events. Dye trace results, structural and topographic controls, spring characteristics, and normalized base flow were used to establish groundwater basin limits and boundary zones and to develop a conceptual sitewide groundwater flow model. The primary finding of this work indicates sitewide groundwater flow is controlled directly or indirectly by local stratigraphy, geologic structure, and changes in stream levels in the geologic past, and that two groundwater basins dominate the study area, accounting for approximately 80% of measured sitewide groundwater discharge. The findings of this investigation will be used to assess the groundwater contaminant contribution from source areas in individual basins, develop an effective groundwater monitoring program, and guide future groundwater management strategies. (C) 2002 Published by Elsevier Science B.V

Can we simulate regional groundwater flow in a karst system using equivalent porous media models? Case study, Barton Springs Edwards aquifer, USA, 2003, Scanlon B. R. , Mace R. E. , Barrett M. E. , Smith B. ,

Various approaches can be used to simulate groundwater flow in karst systems, including equivalent porous media distributed parameter, lumped parameter, and dual porosity approaches, as well as discrete fracture or conduit approaches. The purpose of this study was to evaluate two different equivalent porous media approaches: lumped and distributed parameter, for simulating regional groundwater flow in a karst aquifer and to evaluate the adequacy of these approaches. The models were applied to the Barton Springs Edwards aquifer, Texas. Unique aspects of this study include availability of detailed information on recharge from stream-loss studies and on synoptic water levels, long-term continuous water level monitoring in wells throughout the aquifer, and spring discharge data to compare with simulation results. The MODFLOW code was used for the distributed parameter model. Estimation of hydraulic conductivity distribution was optimized by using a combination of trial and error and automated inverse methods. The lumped parameter model consists of five cells representing each of the watersheds contributing recharge to the aquifer. Transient simulations were conducted using both distributed and lumped parameter models for a 10-yr period (1989-1998). Both distributed and lumped parameter models fairly accurately simulated the temporal variability in spring discharge; therefore, if the objective of the model is to simulate spring discharge, either distributed or lumped parameter approaches can be used. The distributed parameter model generally reproduced the potentiometric surface at different times. The impact of the amount of pumping on a regional scale on spring discharge can be evaluated using a lumped parameter model; however, more detailed evaluation of the effect of pumping on groundwater levels and spring discharge requires a distributed parameter modeling approach. Sensitivity analyses indicated that spring discharge was much more sensitive to variations in recharge than pumpage, indicating that aquifer management should consider enhanced recharge, in addition to conservation measures, to maintain spring flow. This study shows the ability of equivalent porous media models to simulate regional groundwater flow in a highly karstified aquifer, which is important for water resources and groundwater management. (C) 2003 Elsevier Science B.V. All rights reserved

Hydrogeologic and climatic influences on spatial and interannual variation of recharge to a tropical karst island aquifer, 2003, Jones I. C. , Banner J. L. ,

[1] The hydrology and geochemistry of groundwater in tropical island aquifers, such as on Barbados, are significantly influenced by tropical climatic conditions. Recharge to these aquifers is the product of regional and local climate patterns that control rainfall. Oxygen isotopes can be used to estimate the amount and timing of recharge on these islands because seasonal fluctuations of rainwater oxygen isotopic compositions are related to the amount of rainfall. This study shows that estimates of average annual recharge to the limestone aquifer on Barbados vary widely, displaying a more direct relationship to the distribution of rainfall throughout each year than to total annual rainfall. Recharge estimates are higher during years when rainfall is concentrated in the peak wet season months than during years when rainfall is more evenly distributed throughout the year. The El Nino-Southern Oscillation appears to be partially responsible for these rainfall and recharge fluctuations. Knowledge of interannual variation of recharge and processes responsible is important because recharge variation must be considered when setting groundwater management policies related to groundwater availability

Karst groundwater: a challenge for new resources, 2005, Bakalowicz M,

Karst aquifers have complex and original characteristics which make them very different from other aquifers: high heterogeneity created and organised by groundwater flow; large voids, high flow velocities up to several hundreds of m/h, high flow rate springs up to some tens of in 3/S. Different conceptual models, known from the literature, attempt to take into account all these particularities. The study methods used in classical hydrogeology-bore hole, pumping test and distributed models-are generally invalid and unsuccessful in karst aquifers, because the results cannot be extended to the whole aquifer nor to some parts, as is done in non-karst aquifers. Presently, karst hydrogeologists use a specific investigation methodology (described here), which is comparable to that used in surface hydrology. important points remain unsolved. Some of them are related to fundamental aspects such as the void structure only a conduit network, or a conduit network plus a porous matrix -, the functioning - threshold effects and nonlinearities -, the modeling of the functioning - double or triple porosity, or viscous flow in conduits - and of karst genesis. Some other points deal with practical aspects, such as the assessment of aquifer storage capacity or vulnerability, or the prediction of the location of highly productive zones

Karst groundwater management by defining protection zones based on regional geological structures and groundwater flow fields, 2006, Hao Yonghong, Yeh Tian Chyi, Hu Caihong, Wang Yanrong, Li Xia,

Validation of vulnerability mapping methods by field investigations and numerical modelling, 2008, Neukum Christoph, Hotzl Heinz, Himmelsbach Thomas

Vulnerability maps illustrate the potential threat of contaminants to groundwater and can be considered as important tools for land-use planning and related legislation. For karst areas with characteristic preferential infiltration conditions, vulnerability maps are also excellent tools for source and resource protection. However, the resulting qualitative maps are often inconsistent and even contradictive and thus might lead to inconclusive vulnerability assessments. The results of a validation of vulnerability maps produced using four different methods, DRASTIC, GLA, PI and EPIK, are reported for a karst area in southwest Germany. By means of measured hydraulic and transport parameters of the geological sequence, numerical simulations were used based on a conceptual model for the area under study. The mean transit time through the unsaturated zone (resource protection) was used as the validation parameter. The study demonstrates that the highest level of accuracy is achieved with the GLA- and PI methods. Both DRASTIC and EPIK are not able to incorporate highly variable distributions and thickness of cover sediments and their protective properties in the respective mapping procedure. Thus, vulnerability maps produced with DRASTIC, EPIK, and related methods should be used with care when employed in vulnerability assessments for land use planning and related decision-making.
Les cartes de vulnerabilite illustrent la menace potentielle des contaminants envers les eaux souterraines, et peuvent etre considerees comme des outils importants en matiere d'amenagement foncier et de reglementation associee. Sur les domaines karstiques, caracterises par des conditions d'infiltration preferentielle, ces cartes sont egalement d'excellents outils de protection des sources et des ressources. Cependant, les cartes qualitatives resultantes sont generalement incoherentes voire contradictoires, et peuvent par la-meme mener a des evaluations de vulnerabilite peu concluantes. La presente etude expose les resultats de validation de cartes de vulnerabilite produites selon quatre methodes differentes (DRASTIC, GLA, PI et EPIK), dans le cas d'un domaine karstique du sud-est de l'Allemagne. Par le biais des parametres de transport et hydrauliques mesures sur la sequence geologique, des simulations numeriques basees sur un modele conceptuel du secteur d'etude ont ete utilisees. Les temps de transit moyens a travers la zone non saturee (protection de la ressource) ont ete utilises comme parametres de validation. L'etude demontre que le niveau maximum de precision est obtenu par les methodes GLA et PI. Dans la phase de cartographie, les methodes EPIK et DRASTIC sont incapables d'integrer une forte variabilite dans les distributions et les epaisseurs de sediments de couverture, ainsi que dans leurs potentiels de protection. Aussi, les cartes de vulnerabilite produites par les methodes DRASTIC et EPIK doivent etre utilisees avec precaution dans le cadre des evaluations de vulnerabilite a but decisionnaire pour les amenagements fonciers.
Los mapas de vulnerabilidad ilustran la amenaza potencial de contaminantes para el agua subterranea y pueden ser considerados herramientas importantes para planeamiento del uso de la tierra y legislacion relacionada. Para areas carsticas con sus caracteristicas condiciones de infiltracion preferencial, los mapas de vulnerabilidad son tambien excelentes herramientas para proteccion de fuentes y recursos. Sin embargo, los mapas cualitativos resultantes son frecuentemente inconsistentes y hasta contradictorios y por lo tanto podrian conducir a evaluaciones de vulnerabilidad no concluyentes. Los resultados de una validacion de mapas de vulnerabilidad producidos usando cuatro metodos diferentes, DRASTIC, GLA, PI y EPIK, son presentados aqui para un area carstica en Alemania suroccidental. Se usaron simulaciones numericas usando parametros hidraulicos y de transporte medidos de la secuencia geologica y basandose en un modelo conceptual del area en estudio. El tiempo promedio de transito a traves de la zona no saturada (proteccion del recurso) fue utilizado como el parametro de validacion. El estudio demuestra que el maximo nivel de precision es alcanzado con los metodos GLA y PI. DRASTIC y EPIK no fueron capaces de incorporar distribuciones altamente variables ni espesor de sedimentos de cubierta y sus propiedades protectivas en el respectivo procedimiento de elaboracion de mapas. Por lo tanto los mapas de vulnerabilidad producidos con DRASTIC, EPIK y metodos relacionados deberian ser usados con cuidado cuando se usen en evaluaciones de vulnerabilidad para planeamiento del uso de tierra

Phreatic drainage conduits within quartz sandstone: Evidence from the Jurassic Precipice Sandstone, Carnarvon Range, Queensland, Australia, 2009, Wray R.

Discrete underground drainage conduits in quartz sandstones are far less common than in limestones. This paper provides field evidence from the quartzose Precipice Sandstone in the Carnarvon Range of south-central Queensland, Australia, for tubular underground drainage networks similar in many ways to limestone conduits. Diameters range from less than 1 or 2 cm to over 1.5 m, most display a near-circular to oval cross-section that seems to suggest phreatic or epiphreatic development, and the internal surfaces of many are case-hardened by secondary silica deposits. A number of the region's perennial springs appear to be fed by such tubes. The dominant vertical jointing of the quartz sandstone and relatively high permeability of the sandstone are important controls on tube formation. Solutional weathering of the sandstone is widespread, and is followed by the removal of loosened sand grains by flowing underground water, the process of ‘arenisation’. Tube development would appear to have been happening for a very long time, and may still be occurring. A model for tube network formation is proposed. These findings highlight our potentially poor understanding of groundwater flow within some quartz sandstones, and may have important groundwater management implications.

TIME SERIES ANALYSIS, MODELLING AND ASSESSMENT OF OPTIMAL EXPLOITATION OF THE NEMANJA KARST SPRINGS, SERBIA, 2010, Jemcov I. , Petri? M.

The time series analysis was applied in the case-study of a karst aquifer in Serbia in order to study its functioning, hydrodynamic behavior and hydraulic properties. Focusing on the definition of groundwater budget, due to very complex functioning of karst systems the correlation and spectral analyses were used to emphasize the importance of transforming the input data – precipitation to effective infiltration. Thee characterization of karst aquifer was further improved by separating the output component – discharge to base flow and flatfoot components. Additionally, the importance of these transformations was proved in application of the regression model for the simulation of discharges based on the effective infiltration functions. A recharge-discharge model was applied in accordance with the active groundwater management, defining optimal “exploitable” regimes, which included the analyses of storage changes in karst water reservoirs under natural conditions, and calculation of the potential exploitation conditions.

Relative importance of the saturated and the unsaturated zones in the hydrogeological functioning of karst aquifers: The case of Alta Cadena (Southern Spain), 2011, Mudarra M. , Andreo B.

From analysis of the hydrodynamic and hydrochemical responses of karst springs, it is possible to know the behaviour of the aquifers they drain. This manuscript aims to contribute to the characterization of infiltration process, and to determine the relative importance of the saturated zone and of the unsaturated zone in the hydrogeological functioning of carbonate aquifers, using natural hydrochemical tracers. Thus, chemical components together with temperature and electrical conductivity (both punctual and continuous records) have been monitored in three springs which drain Alta Cadena carbonate aquifer, Southern Spain. An evaluation of the percentage of the electrical conductivity frequency peaks determined for each of the three springs is linked to the chemical parameters that comprise the conductivity signal. One of these springs responds rapidly to precipitation (conduit flow system), due to the existence of a high degree of karstification in the unsaturated zone and in the saturated zone, both of which play a similar role in the functioning of the spring. Another spring responds to precipitation with small increases in water flow, somewhat lagged, because the aquifer has a low degree of karstification, even in the unsaturated zone, which seems to influence its functioning more strongly than does the saturated zone. The third spring drains a sector of the aquifer with a moderately developed degree of karstification, one that is intermediate between the other two, in which both the unsaturated zone and the saturated zone participate in the functioning of the spring, but with the latter zone having a stronger influence. These three springs show different hydrogeological functioning although they are in similar geological and climatic contexts, which show the heterogeneity of karst media and the importance of an adequate investigation for groundwater management and protection in karst areas.

Research highlights
- From analysis of the hydrodynamic and hydrochemical responses of karst springs. - Characterization of the relative importance of the saturated (SZ) and unsaturated (NSZ) zones - Villanueva del Rosario: NSZ and SZ play similar roles in the functioning of the system. ► Pita: NSZ seems to affect its functioning more than SZ. - Parroso: NSZ and SZ participate in the functioning of the system, but SZ is more active.

Karst Groundwater Management through Science and Education, 2011, Guo Fang, Jiang Guanghui

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

Review: The Yucatan Peninsula karst aquifer, Mexico , 2011, Bauergottwein Peter, Gondwe Bibi R. N. , Charvet Guillaume, Marin Luis E. , Rebolledovieyra Mario, Meredizalonso Gonzalo

The Yucatan Peninsula karst aquifer is one of the most extensive and spectacular karst aquifer systems on the planet. This transboundary aquifer system extends over an area of approximately 165,000 km2 in Mexico, Guatemala and Belize. The Triassic to Holocene Yucatan limestone platform is located in the vicinity of the North American/Caribbean plate boundary and has been reshaped by a series of tectonic events over its long geologic history. At the end of the Cretaceous period, the Yucatan Peninsula was hit by a large asteroid, which formed the Chicxulub impact crater. The Yucatan Peninsula karst aquifer hosts large amounts of groundwater resources which maintain highly diverse groundwater-dependent ecosystems. Large parts of the aquifer are affected by seawater intrusion. Anthropogenic pollution of the aquifer has been increasing over the past few decades, owing to relentless economic development and population growth on the Peninsula. This review summarizes the state of knowledge on the Yucatan Peninsula karst aquifer and outlines the main challenges for hydrologic research and practical groundwater-resources management on the Peninsula.

Modified DRASTIC assessment for intrinsic vulnerability mapping of karst aquifers: a case study , 2011, Mimi Ziad A. , Mahmoud Nidal, Abu Madi Maher

Groundwater in karstic aquifers can be dangerously sensitive to contamination. In this paper, DRASTIC assessment was modified and applied, for the first time, to address the intrinsic vulnerability for karst aquifers. The theoretical weights of two of DRASTIC’s parameters (aquifer media and hydraulic conductivity) were modified through sensitivity analysis. Two tests of sensitivity analyses were carried out: the map removal and the single parameter sensitivity analyses. The modified assessment was applied for the karst aquifers underlying Ramallah District (Palestine) as a case study. The aquifer vulnerability map indicated that the case study area is under low, moderate and high vulnerability of groundwater to contamination. The vulnerability index can assist in the implementation of groundwater management strategies to prevent degradation of groundwater quality. The modified DRASTIC assessment has proven to be effective because it is relatively straightforward, use data that are commonly available or estimated and produces an end product that is easily interpreted.

Review: The Yucatán Peninsula karst aquifer, Mexico, 2011, Bauergottwein P. , Gondwe B. R. N. , Charvet G. , Marín L. E. , Rebolledovieyra M. , Meredizalonso G.

The Yucatán Peninsula karst aquifer is one of the most extensive and spectacular karst aquifer systems on the planet. This transboundary aquifer system extends over an area of approximately 165,000 km2 in México, Guatemala and Belize. The Triassic to Holocene Yucatán limestone platform is located in the vicinity of the North American/Caribbean plate boundary and has been reshaped by a series of tectonic events over its long geologic history. At the end of the Cretaceous period, the Yucatán Peninsula was hit by a large asteroid, which formed the Chicxulub impact crater. The Yucatán Peninsula karst aquifer hosts large amounts of groundwater resources which maintain highly diverse groundwater-dependent ecosystems. Large parts of the aquifer are affected by seawater intrusion. Anthropogenic pollution of the aquifer has been increasing over the past few decades, owing to relentless economic development and population growth on the Peninsula. This review summarizes the state of knowledge on the Yucatán Peninsula karst aquifer and outlines the main challenges for hydrologic research and practical groundwater-resources management on the Peninsula