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Sample records for karst asfalta maisjuma

  1. Agriculture and Karst in Kentucky

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This publication describes the unique hydrologic and environmental issues found in karst environments. The publication describes karst landscapes, the importance of karst, different types of karst features, and how water moves through karst landscapes. The publication includes details on methods for...

  2. Recent Trends in Karst Geomorphology.

    ERIC Educational Resources Information Center

    Palmer, Arthur N.

    1984-01-01

    Recent trends related to the karst processes and the evolution of karst landscapes are discussed. The hydrochemical processes responsible for the origin of karst are expanded on to illustrate the present scope of karst studies. These geomorphological studies are combined with concepts and techniques from hydraulics, chemistry, and mathematics. (JN)

  3. Speleogenesis in Dinaric karst area

    NASA Astrophysics Data System (ADS)

    Garasic, Mladen; Garasic, Davor

    2015-04-01

    Dinaric Karst is one of the largest karst regions in Europe and in the World. It is the paramount karst of Europe and type site of many karst features. Dinaric Karst Area covers an extensive part of the Dinarides, a mountain chain in Southern Europe named after Dinara Mt., an impressive and outstanding rocky wall on the border between Dalmatian part of Croatia and Bosnia and Herzegovina. The Dinaric Karst occupies an area from the Friuli Plain (Doberdo Karst Plateau) and Slovenian mountains near Postojna cave on the northwest, to Skadar Lake and Prokletije Mt. on the southeast, from Central Bosnian Mountains on the northeast, and the Adriatic Sea seafloor with its islands. The Dinarides outspread in a so-called "Dinaric strike" (NW-SE) for 650 km in length and are up to 150 km wide across SW-NE. The biggest part of the Dinaric Karst Area is situated within Croatian territory (continental, Adriatic coastal and seafloor karst) comprising all karst features with exceptional examples exposed on the surface as well as in the underground. Classical karst area is the one situated in Slovenia, where typical karst features were described for the first time. Presentation of the outstanding values of Dinaric karst is based on the values that can be met in Italy, Bosnia and Herzegovina, Montenegro, Serbia and Albania, too. Dinaric Karst is the World's natural heritage because of its unique and outstanding geological characteristics and its living world; some of them are of outstanding natural beauty. Dinaric karst is an integral, compact karst area with extremely great thickness of carbonate rocks of predominantly Mesozoic age which in some areas exceeds 8.000 m. It bears several cycles of karstification thus giving world uniqueness to the area, especially regarding the wealth of submerged karst phenomena, among which vruljes are world unique features. Dinaric karst is one of the largest karst regions in the World. From the scientific perspective, the Dinaric Karst is one of

  4. Evaporite karst in Sicily

    NASA Astrophysics Data System (ADS)

    Liguori, V.; Manno, G.; Mortellaro, D.

    2008-01-01

    Karst areas are distributed over most of Sicily. The most widespread karst rocks are carbonates, particularly limestones, but karst phenomena can also be seen in evaporites and particularly in salt mines. This report provides an overview of evaporite karst in Sicily, along with a “case history” that shows some of the evaporite karst risks to the environment. In the centre and south of Sicily, a thick sequence of Messinian evaporite rocks are subject to dissolution from meteoric and formation waters. In areas where potassium salts and rock salts are being mined, some geomorphologic changes result from the drilling of boreholes and the collapse of underground mines, thus lowering or collapsing the land surface. An example is the old salt mine “Muti-Coffari”, situated in the commune of Cammarata, where there is a modification of the surface flow of the River Platani. Meteoric waters and runoff flow down through a borehole, enter the underground mine cavity and dissolve the salts, and then the resulting brine flows into a branch of the river, making it salty. Field investigations showed the presence of salt along the edges and on the bed of the stream where it comes out of the cave. Therefore, interventions for risk mitigation are necessary since the old mine constitutes a serious danger for damage or collapse of nearby infrastructures, and can lead to degradation of the river ecosystem and the natural environment.

  5. Landfills in karst terrains

    SciTech Connect

    Hughes, T.H. ); Memon, B.A.; LaMoreaux, P.E. )

    1994-06-01

    State and Federal regulations have established restrictions for location of hazardous waste and municipal, solid waste landfills. Regulations require owners/operators to demonstrate that the hydrogeology has been completely characterized at proposed landfills, and that locations for monitoring wells have been properly selected. Owners/operators are also required to demonstrate that engineering measures have been incorporated in the design of the municipal solid waste landfills, so that the site is not subject to destabilizing events, as a result of location in unstable areas, such as karst terrains. Karst terrains are typically underlain by limestone or dolomite, and may contain a broad continuum of karst features and karst activity. Preliminary investigation of candidate sites will allow ranking of the sites, rejection of some unsuitable sites, and selection of a few sites for additional studies. The complexity of hydrogeologic systems, in karst terrains, mandates thorough hydrogeologic studies to determine whether a specific site is, or can be rendered, suitable for a land disposal facility. Important components of hydrogeologic studies are: field mapping of structural and stratigraphic units; interpretation of sequential aerial photographs; test drilling and geophysical analyses; fracture analyses; seasonal variation in water-levels; spatial variation of hydraulic characteristics of the aquifer and aquiclude; velocity and direction of movement of ground water within aquifers; determination of control for recharge, discharge, and local base level; and evaluation of the effects of man's activities, such as pumping, dewatering and construction.

  6. Decade of karst risk assessment

    NASA Astrophysics Data System (ADS)

    Yolkin, Vladimir

    2010-05-01

    Karst is one of the most hazardous processes on the Earth, at about 13% of the Russian area, including more than 300 towns and thousands of smaller settlements with 19% of the total population of Russia, are subject to karst deformations (Ragozin, 1994). During the time period 2000-2004, regional karst hazard and risk assessment was developed as an example of the Tatarstan Republic (Ragozin and Yolkin, 2003). The published paper was the first Russian research paper dedicated the technique and cartographic examples of probabilistic-deterministic risk assessment from karst processes. At present time, the technique of assessment of karst risk is improved, as well as investigations with reference to various areal or linear recipients are performed. In particular, for the pipeline systems the assessment of karst economic risk adapts, according to two scenarios: the pessimistic one (the most adverse in consequences) and the most probable (Yolkin and Anikeev, 2007, Yolkin, 2008,2009). By karst risk we mean the probabilistic index of hazard of karst and karst-suffosion sinkholes and surface settlements established for a certain object as it possible losses in various spheres for a given time period. Quantitative karst-hazard and risk assessment is carried out on the basis of the analysis of geological structure of territory, hydrogeological and engineering-geological conditions of territory, identification and prediction of karst hazards in time and space, assessment of vulnerability of objects to karst hazards, ranking and mapping of karst hazards as well as karst economic, social risks of losses. The obtained values of economic or social risk are the basis for choosing engineering protection measures, alternative design solutions and for estimating service conditions. It is necessary to mention that the procedure of vulnerability assessment is poorly developed with reference not only to karst sinkholes, but also to dangerous geological processes in general. For

  7. Speleogenesis in Dinaric karst area

    NASA Astrophysics Data System (ADS)

    Garasic, Mladen; Garasic, Davor

    2015-04-01

    Dinaric Karst is one of the largest karst regions in Europe and in the World. It is the paramount karst of Europe and type site of many karst features. Dinaric Karst Area covers an extensive part of the Dinarides, a mountain chain in Southern Europe named after Dinara Mt., an impressive and outstanding rocky wall on the border between Dalmatian part of Croatia and Bosnia and Herzegovina. The Dinaric Karst occupies an area from the Friuli Plain (Doberdo Karst Plateau) and Slovenian mountains near Postojna cave on the northwest, to Skadar Lake and Prokletije Mt. on the southeast, from Central Bosnian Mountains on the northeast, and the Adriatic Sea seafloor with its islands. The Dinarides outspread in a so-called "Dinaric strike" (NW-SE) for 650 km in length and are up to 150 km wide across SW-NE. The biggest part of the Dinaric Karst Area is situated within Croatian territory (continental, Adriatic coastal and seafloor karst) comprising all karst features with exceptional examples exposed on the surface as well as in the underground. Classical karst area is the one situated in Slovenia, where typical karst features were described for the first time. Presentation of the outstanding values of Dinaric karst is based on the values that can be met in Italy, Bosnia and Herzegovina, Montenegro, Serbia and Albania, too. Dinaric Karst is the World's natural heritage because of its unique and outstanding geological characteristics and its living world; some of them are of outstanding natural beauty. Dinaric karst is an integral, compact karst area with extremely great thickness of carbonate rocks of predominantly Mesozoic age which in some areas exceeds 8.000 m. It bears several cycles of karstification thus giving world uniqueness to the area, especially regarding the wealth of submerged karst phenomena, among which vruljes are world unique features. Dinaric karst is one of the largest karst regions in the World. From the scientific perspective, the Dinaric Karst is one of

  8. Karst Map of Puerto Rico

    USGS Publications Warehouse

    Aleman-Gonzalez, Wilma B.

    2010-01-01

    This map is a digital compilation, combining the mapping of earlier geologists. Their work, cited on the map, contains more detailed descriptions of karst areas and landforms in Puerto Rico. This map is the basis for the Puerto Rico part of a new national karst map currently being compiled by the U.S. Geological Survey. In addition, this product is a standalone, citable source of digital karst data for Puerto Rico. Nearly 25 percent of the United States is underlain by karst terrain, and a large part of that area is undergoing urban and industrial development. Accurate delineations of karstic rocks are needed at scales suitable for national, State, and local maps. The data on this map contribute to a better understanding of subsidence hazards, groundwater contamination potential, and cave resources as well as serve as a guide to topical research on karst. Because the karst data were digitized from maps having a different scale and projection from those on the base map used for this publication, some karst features may not coincide perfectly with physiographic features portrayed on the base map.

  9. Karst hydrology and chemical contamination

    SciTech Connect

    Field, M.S.

    1993-01-01

    Ground-water flow in karst aquifers is very different from flow in granular or fractured aquifers. Chemical contamination may be fed directly to a karst aquifer via overland flow to a sinkhole with little or no attenuation and may contaminate downgradient wells, springs, and sinkholes within a few hours or a few days. Contaminants may also become temporarily stored in the epikarstic zone for eventual release to the aquifer. Flood pulses may flush the contaminants to cause transiently higher levels of contamination in the aquifer and discharge points. The convergent nature of flow in karst aquifers may result in contaminants becoming concentrated in conduits. Once contaminants have reached the subsurface conduits, they are likely to be rapidly transported to spring outlets. Traditional aquifer remediation techniques for contaminated aquifers are less applicable to karst aquifers.

  10. An In-Depth Exploration of Karst.

    ERIC Educational Resources Information Center

    Jackson, Julia A.; Zokaites, Carol; Smith, Michael J.; Crum, Emily; Callahan, Caitlin

    2001-01-01

    Explains how a karst is formed in the U.S. and introduces an activity in which students explore the fragile environment of a karst and study the interactions between human population and the earth system. (YDS)

  11. Wildfire on Karst: an Overview

    NASA Astrophysics Data System (ADS)

    Coleborn, K.; Lupingna, A.; Flemons, I.; Nagra, G.; Treble, P. C.; Andersen, M. S.; Baker, A.; Tozer, M.; Fairchild, I. J.; Baker, A.; Meehan, S.

    2015-12-01

    Wildfires dramatically change the surface environment by removing vegetation and soil microbial communities and altering soil structure and geochemistry. Karst subsurface processes such as dissolution, cave formation and speleothem deposition are sensitive to environmental change, which is precisely why speleothems have been widely used as recorders of surface and climate change at an annual to millennial temporal scale. The effect of fire on karst processes is poorly understood. We hypothesise that a wildfire induced change at the surface will impact karst dissolution and precipitation processes. Firstly, sterilisation of the soil by heating causes a reduction in soil CO2 concentration which is a key component in dissolution processes. Secondly, removal of vegetation alters surface albedo and soil water storage properties. This could change the hydrology and isotopic signature of speleothem-forming drip water. We also hypothesise that a wildfire will produce a unique biogeochemical signature due to a change in the organic and inorganic properties of soil, which can be transported into speleothem forming drip water. Fire changes the organic matter character which is an important component in the mobilisation and transport of trace metals. Combustion of vegetation results in addition of ash derived minerals to the soil. Quantifying the biogeochemical signature from a burnt landscape will enable us to determine whether this wildfire signature is preserved in speleothems. This would provide the opportunity to use speleothems as recorders of fire history for the first time. Determining the impact of fire on karst processes would inform fire management and karst conservation policies.

  12. Karst morphology and groundwater vulnerability of high alpine karst plateaus

    NASA Astrophysics Data System (ADS)

    Plan, Lukas; Decker, Kurt; Faber, Robert; Wagreich, Michael; Grasemann, Bernhard

    2009-07-01

    High alpine karst plateaus are recharge areas for major drinking water resources in the Alps and many other regions. Well-established methods for the vulnerability mapping of groundwater to contamination have not been applied to such areas yet. The paper characterises this karst type and shows that two common vulnerability assessment methods (COP and PI) classify most of the areas with high vulnerability classes. In the test site on the Hochschwab plateau (Northern Calcareous Alps, Austria), overlying layers are mostly absent, not protective or even enhance point recharge, where they have aquiclude character. The COP method classifies 82% of the area as highly or extremely vulnerable. The resulting maps are reasonable, but do not differentiate vulnerabilities to the extent that the results can be used for protective measures. An extension for the upper end of the vulnerability scale is presented that allows identifying ultra vulnerable areas. The proposed enhancement of the conventional approach points out that infiltration conditions are of key importance for vulnerability. The method accounts for karst genetical and hydrologic processes using qualitative and quantitative properties of karst depressions and sinking streams including parameters calculated from digital elevations models. The method is tested on the Hochschwab plateau where 1.7% of the area is delineated as ultra vulnerable. This differentiation could not be reached by the COP and PI methods. The resulting vulnerability map highlights spots of maximum vulnerability and the combination with a hazard map enables protective measures for a manageable area and number of sites.

  13. KarstALEA - a scientifically based method to predict karst-related hazards in underground constructions

    NASA Astrophysics Data System (ADS)

    Schmassmann, S.; Filliponi, M.; Jeannin, P.-Y.; Parriaux, A.; Malard, A.; Vouillamoz, J.

    2012-04-01

    In underground construction in carbonate rocks, karst is a major issue. Karst occurrences entail specific hazards such as large voids, massif water inflow or sediment-filled voids. The underground construction itself as well as the environment can be affected (e.g. drying springs, sinkhole formation). Karst-related hazards can cause amongst others important delays, additional costs, safety-related problems on the construction site or the abandonment of a project. Until know, most investigation methods considered karst occurrences as randomly distributed and unpredictable. However, recent research based on the 3D analysis of cave systems proved that up to 80% of karst conduits are located on few inception features. Inception features are discontinuities (e.g. bedding planes, beddings of mm to cm thickness with a contrasting mineralogy or primary permeability, joints, faults), which are particularly susceptible to karstification. Further, the karst conduit density and their characteristics depend on the locally dominant speleogenetic processes. Based on that, so-called speleogenetic zones can be delimitated. Karst conduit density is highest near the surface, where water drainage is concentrated with depth, and around the water table, where water is drained to the spring(s). As the spatial distribution of dominant speleogenetic processes change with time, paleo-speleogenetic zones can be delimitated. This is particularly important for the paleo-speleogenetic zones corresponding to past water tables. The KarstALEA method combines the inception feature concept, knowledge about the spatial distribution of dominant - actual and past - speleogenetic processes (speleogenetic zones) and hydrogeological considerations. These leads to two major results: (1) the spatial distribution of karst occurrence probability (zones of characteristic karst conduit density); (2) the spatial distribution and characteristics of karst-related hazards, e.g. size and geometry of karst conduits

  14. A glossary of Karst terminology

    USGS Publications Warehouse

    Monroe, Watson Hiner

    1970-01-01

    This glossary includes most terms used in describing karst geomorphologic features and processes. The terms are primarily those used in the literature of English-speaking countries, but a few of the more common terms in French, German, and Spanish are included, with references to the corresponding English terms where they are available. The glossary also includes simple definitions of the more common rocks and minerals found in karst terrain, common terms of hydrology, and a number of the descriptive terms used by speleologists. The glossary does not include definitions of most biospeleological terms, geologic structure terms, varieties of carbonate rock that require microscopic techniques for identification, or names describing tools and techniques of cave exploration.

  15. Karst subsidence in East Tennessee

    SciTech Connect

    Ketelle, R.H.; Newton, J.G.; Tanner, J.M.

    1988-01-01

    Waste disposal site selection and facility design in regions dominated by carbonate bedrock must carefully consider karst development and the factors which contribute to subsidence activity. The Department of Energy's (DOE) Oak Ridge National Laboratory has completed a three phase study of karst subsidence in East Tennessee to quantify historical subsidence activity. The purpose of the study was to determine the principal factors which cause karst subsidence in the region. Techniques used and results obtained in this study form a basis for more detailed risk assessment at the local scale within the region. As development pressures diminish available land for various uses, risk-based land use decisions must be made to site critical facilities. To fulfill the study objectives a three phase study was designed including, (1) collection of subsidence data and compilation of a database, (2) performance of detailed studies of subsidence in three, two-to-five square-mile areas, and (3) synthesis of data obtained to; quantify the predominant sinkhole collapse dimensions, and identify events prior to subsidence or collapse events which may have caused the event, and estimate the intensity of subsidence as a function of geologic unit within subregional areas of higher and lower subsidence risk. 4 refs., 7 figs., 2 tabs.

  16. Treating tar sands formations with karsted zones

    SciTech Connect

    Vinegar, Harold J.; Karanikas, John Michael

    2010-03-09

    Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

  17. Transport of agricultural contaminants through karst soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst landscapes are common in many agricultural regions in the US. Well-developed karst landscapes are characterized by shallow soils, sinkholes, sinking streams, underground conduits, and springs. In these landscapes surface runoff is minimal and most recharge enters the subsurface relatively quic...

  18. Karst development in central Butler County, Kansas

    SciTech Connect

    Bain, B.A.

    1993-02-01

    Research was conducted to study the geology and hydrology of sinkholes, springs, and caves formed in Lower Permian, Fort Riley Limestone, located in central Butler County, Kansas. The goal was to better understand the controlling factors of these karst features and the processes that produce them in a portion of Kansas that is undergoing rapid population growth and increased groundwater usage. Research was accomplished in seven phases: literature search, locating karst features, measuring bedrock fracture joint trends, surveying major caves, estimating discharge of springs, dye tracing, and water chemistry analysis. Recognizable karst landforms within the study area were plotted onto a base map to demonstrate their geographic, geologic, and hydrologic relationships. Karst features identified were 125 sinkholes, a major cave system composed of at least three enterable cave segments, and one large spring. The karst terrain found within the study area is clearly a system of interrelated features and processes. Long-term solution of the bedrock allows karst features to form, joints and bedding planes to enlarge, and creates an efficient network of subsurface drainage. Factors that control karst development in the study area are lithology, thickness, and dip of the bedrock; presence of well defined joints and bedding planes; relatively level topography; nearby entrenched river valleys; lack of thick surficial cover; and climate. Of these influences, solutional activity at joints plays a major role in the formation of sinkholes and cave passages; however, a complex combination of all the controlling factors is responsible for the present, unique, and dynamic karst system.

  19. Geophysical imaging of karst features in Missouri

    NASA Astrophysics Data System (ADS)

    Obi, Jeremiah Chukwunonso

    Automated electrical resistivity tomography (ERT) supported with multichannel analysis of surface waves (MASW) and boring data were used to map karst related features in Missouri in order to understand karst processes better in Missouri. Previous works on karst in Missouri were mostly surficial mapping of bedrock outcrops and joints, which are not enough to define the internal structure of karst system, since most critical processes in karst occur underground. To understand these processes better, the density, placement and pattern of karst related features like solution-widened joints and voids, as well as top of bedrock were mapped. In the course of the study, six study sites were visited in Missouri. The sites were in Nixa, Gasconade River Bridge in Lebanon, Battlefield, Aurora, Protem and Richland. The case studies reflect to a large extent some of the problems inherent in karst terrain, ranging from environmental problems to structural problems especially sinkhole collapses. The result of the study showed that karst in Missouri is mostly formed as a result of piping of sediments through solution-widened joints, with a pattern showing that the joints/fractures are mostly filled with moist clay-sized materials of low resistivity values. The highest density of mapped solution-widened joints was one in every one hundred and fifty feet, and these areas are where intense dissolution is taking place, and bedrock pervasively fractured. The study also showed that interpreted solution-widened joints trend in different directions, and often times conform with known structural lineaments in the area. About 40% of sinkhole collapses in the study areas are anthropogenic. Karst in Missouri varies, and can be classified as a combination of kI (juvenile), kIII (mature) and kIV (complex) karsts.

  20. Negative grouting consequences on karst environment

    NASA Astrophysics Data System (ADS)

    Bonacci, O.; Roje-Bonacci, T.; Gottstein, S.

    2009-04-01

    Grouting is a procedure by means of which grout is injected into different kinds of karst spaces (cracks, fissures, conduits and caves). It has a wide application in modern civil engineering, especially in karst terrains. It started nearly 200 years ago. In most cases the ingredients for the preparation of mortars and grouting suspensions are: cement, bentonite, clay and fillers, additives for stability and water. In practice the composition of grouting suspension is not standardized. A suspension injected under pressure will circulate in the karst spaces like a more or less viscous fluid until some of the larger suspended particles are blocked where the karst voids get narrower than the size of injected grains. The injection of materials into karst groundwater, i.e. the construction of grouting curtains, definitely could be the cause of unpredictable negative consequences on karst groundwater environments. The building of dams in karst areas always go along the construction of grouting curtains. During the construction of most dams in karst all over the world millions tons of injection mass have been injected in karst underground. It may impact water quantity in vadose zone and in karstic aquifer causing water table lowering and spring desiccation. In such cases the negative impact on local karst environment could be very dangerous. Physically as well as chemically this mass voraciously and quickly destroyed underground habitats and killed an enormous number of endangered and endemic species. Very often this is extremely expensive procedure and in many cases not very successful from the engineering point of view. From the ecological point of view it could causes catastrophic consequences. The greatest problem is that until now neither engineers nor ecologists took care of these great and massive negative influences on underground karst environments. In this paper few examples of different consequences of grouting on the hydrogeological as well as ecological regime

  1. Karst in evaporites in southeastern New Mexico

    SciTech Connect

    Bachman, G.O.

    1987-09-01

    Permian evaporites in southeastern New Mexico include gypsum, anhydrite, and salt, which are subject to both blanket and local, selective dissolution. Dissolution has produced many hundreds of individual karst features including collapse sinks, karst valleys, blind valleys, karst plains, caves, and breccia pipes. Dissolution began within some formations during Permian time and has been intermittent but continual ever since. Karst features other than blanket deposits of breccia are not preserved from the early episodes of dissolution, but some karst features preserved today - such as breccia pipes - are remnants of karst activity that was active at least as early as mid-Pleistocene time. Rainfall was much more abundant during Late Pleistocene time, and many features visible today may have been formed then. The drainage history of the Pecos River is related to extensive karstification of the Pecos Valley during mid-Pleistocene time. Large-scale stream piracy and dissolution of salt in the subsurface resulted in major shifts and excavations in the channel. In spite of intensive groundwater studies that have been carried out in the region, major problems in near-surface evaporite karst remain to be solved. Among these are determination of recharge areas and time of recharge. 109 refs., 31 figs., 1 tab.

  2. Sinking karst river Dobra hydrology (Croatia)

    NASA Astrophysics Data System (ADS)

    Bonacci, O.; Andrić, I.

    2009-04-01

    A case of special hydrological characteristics of sinking karst river Dobra is analysed. Its catchment is located in the central part of the Dinaric karst region of Croatia. The Dobra River has three parts. First one calls Upper or Ogulinska Dobra. Its length from the spring to the Djula sink is 51.2 km. The second part flows through karst underground from the Djula sink to the karst spring zone near village Gojak. In order to reappear at the karst springs zone of the Lower or Gojačka Dobra River it flows through cave system 16,396 km long. The shortest aerial distance between Djula sink and the Lower Dobra River karst spring zone is 4.6 km. The longitude of this third part of the Dobra River is 52.1 km. Along the some sections of the open watercourse of the Upper Dobra there are huge water losses through small karst sinks located on the bottom of its channel. The hydrological as well as hydrogeological regime of the Dobra River is strongly influenced by the construction of HEPP Gojak built in 1959. Water from the neighbouring Zagorska Mrežnica River is provided by tunnel to the hydroelectric power plant (HEPP) Gojak situated immediately downstream from the Gojak karst spring zone. By this way mean annual discharge of the Lower Dobra has increased doubly, from about 13.6 to 28 m3/s. At the end of July 1999, the town of Ogulin was flooded. This flood was caused by insufficient swallow capacity of the Djula spring. New changes of hydrological, hydrogeological and ecological characteristics of the Lower Dobra River should be expected in the near future. The HEPP Lešće on the Lower Dobra is currently under construction.

  3. Mapping karst regions of Illinois: Preliminary results

    SciTech Connect

    Weibel, C.P.; Panno, S.V. )

    1993-03-01

    Groundwater contamination may be significant in shallow aquifers in the parts of Illinois where karst occurs. Problems with ground-water contamination in shallow aquifers in karst areas may be significant in parts of Illinois. A study is underway to study factors that contribute to karst development and to map the karst areas of the state, including areas where obvious diagnostic karst geomorphic features are absent. The following generalizations can be made about the structural and stratigraphic factors that control the extent and maturity of karst areas and the development of karstic terrain in Illinois: (1) karstification is restricted to the flanks of the Illinois Basin because most of the basin interior contains carbonate-poor Pennsylvanian bedrock; (2) karstic terrain generally occurs in thick, flatlying, carbonate-rich lithologic units; (3) carbonate to non-carbonate facies changes in formations and the presence of disconformities affect the degree of karstification; (4) structures (folds, faults) may either increase or decrease the likelihood of karstification; and (5) karstification is potentially greater in areas where overlying regolith is absent or thin.

  4. Forecast Verification for North American Mesoscale (NAM) Operational Model over Karst/Non-Karst regions

    NASA Astrophysics Data System (ADS)

    Sullivan, Z.; Fan, X.

    2014-12-01

    Karst is defined as a landscape that contains especially soluble rocks such as limestone, gypsum, and marble in which caves, underground water systems, over-time sinkholes, vertical shafts, and subterranean river systems form. The cavities and voids within a karst system affect the hydrology of the region and, consequently, can affect the moisture and energy budget at surface, the planetary boundary layer development, convection, and precipitation. Carbonate karst landscapes comprise about 40% of land areas over the continental U.S east of Tulsa, Oklahoma. Currently, due to the lack of knowledge of the effects karst has on the atmosphere, no existing weather model has the capability to represent karst landscapes and to simulate its impact. One way to check the impact of a karst region on the atmosphere is to check the performance of existing weather models over karst and non-karst regions. The North American Mesoscale (NAM) operational forecast is the best example, of which historical forecasts were archived. Variables such as precipitation, maximum/minimum temperature, dew point, evapotranspiration, and surface winds were taken into account when checking the model performance over karst versus non-karst regions. The forecast verification focused on a five-year period from 2007-2011. Surface station observations, gridded observational dataset, and North American Regional Reanalysis (for certain variables with insufficient observations) were used. Thirteen regions of differing climate, size, and landscape compositions were chosen across the Contiguous United States (CONUS) for the investigation. Equitable threat score (ETS), frequency bias (fBias), and root-mean-square error (RMSE) scores were calculated and analyzed for precipitation. RMSE and mean bias (Bias) were analyzed for other variables. ETS, fBias, and RMSE scores show generally a pattern of lower forecast skills, a greater magnitude of error, and a greater under prediction of precipitation over karst than

  5. Stochastic simulation of karst conduit networks

    NASA Astrophysics Data System (ADS)

    Pardo-Igúzquiza, Eulogio; Dowd, Peter A.; Xu, Chaoshui; Durán-Valsero, Juan José

    2012-01-01

    Karst aquifers have very high spatial heterogeneity. Essentially, they comprise a system of pipes (i.e., the network of conduits) superimposed on rock porosity and on a network of stratigraphic surfaces and fractures. This heterogeneity strongly influences the hydraulic behavior of the karst and it must be reproduced in any realistic numerical model of the karst system that is used as input to flow and transport modeling. However, the directly observed karst conduits are only a small part of the complete karst conduit system and knowledge of the complete conduit geometry and topology remains spatially limited and uncertain. Thus, there is a special interest in the stochastic simulation of networks of conduits that can be combined with fracture and rock porosity models to provide a realistic numerical model of the karst system. Furthermore, the simulated model may be of interest per se and other uses could be envisaged. The purpose of this paper is to present an efficient method for conditional and non-conditional stochastic simulation of karst conduit networks. The method comprises two stages: generation of conduit geometry and generation of topology. The approach adopted is a combination of a resampling method for generating conduit geometries from templates and a modified diffusion-limited aggregation method for generating the network topology. The authors show that the 3D karst conduit networks generated by the proposed method are statistically similar to observed karst conduit networks or to a hypothesized network model. The statistical similarity is in the sense of reproducing the tortuosity index of conduits, the fractal dimension of the network, the direction rose of directions, the Z-histogram and Ripley's K-function of the bifurcation points (which differs from a random allocation of those bifurcation points). The proposed method (1) is very flexible, (2) incorporates any experimental data (conditioning information) and (3) can easily be modified when

  6. Evaporite karst in the United States

    USGS Publications Warehouse

    Johnson, K.S.

    1997-01-01

    Evaporites, including gypsum (or anhydrite) and salt, are the most soluble of common rocks; they are dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are found in limestones and dolomites. The four basic requirements for evaporite karst to develop are: (1) a deposit of gypsum or salt; (2) water, unsaturated with CaSO4 or NaCl; (3) an outlet for escape of dissolving water; and (4) energy to cause water to flow through the system. Evaporites are present in 32 of the 48 contiguous states, and they underlie about 35-40% of the land area; they are reported in rocks of every geologic system from the Precambrian through the Quaternary. Evaporite karst is known at least locally (and sometimes quite extensively) in almost all areas underlain by evaporites. The most widespread and pronounced examples of both gypsum and salt karst are in the Permian basin of the southwestern United States, but many other areas are also significant. Human activities have caused some evaporite-karst development, primarily in salt deposits. Boreholes may enable (either intentionally or inadvertently) unsaturated water to flow through or against salt deposits, thus allowing development of small to large dissolution cavities. If the dissolution cavity is large enough and shallow enough, successive roof failures above the cavity can cause land subsidence or catastrophic collapse.

  7. Predicting contaminant migration in karst aquifers

    SciTech Connect

    Field, M.S.

    1996-06-01

    Time-of-travel transport estimation is employed to predict contaminant migration in karst aquifers. Estimation of time-of-travel transport is conditioned on the set of hydraulic-flow that occur within karst conduits. These parameters are applied to surface-water models to reflect time-of-travel flow and geometries are determined empirically through quantitative ground-water tracing studies. Quantitative ground-water tracing studies are based on a comprehensive tracer budget and numerical analysis of the tracer recovery curves for time-of-travel parameters that include mean residence time, mean flow velocity, longitudinal dispersivity, karst conduit volume, cross-sectional area, diameter, and hydraulic depth for use in surface-water models.

  8. A groundwater conceptual model and karst-related carbon sink for a glacierized alpine karst aquifer, Southwestern China

    NASA Astrophysics Data System (ADS)

    Zeng, Cheng; Liu, Zaihua; Yang, Jianwen; Yang, Rui

    2015-10-01

    In the Jade Dragon Snow Mountain (JDSM) region, Yunnan Province, SW China, an extensive hydrochemical and stable isotopic study of a glacierized alpine karst aquifer was conducted during the period, 2011-2014. The objectives of the study were: first, to establish a conceptual hydrogeological model of the karst groundwater system; second, to estimate the proportion of extra glacier melt water infiltrating the karst aquifer that is being induced by the regional climate warming; third, to calculate the karst-related flux of carbon into the karst aquifer. Knowledge of the local hydrogeological background from previous work was the starting point of the hydrochemical and stable isotopic study. Some representative spring waters and recharge waters (i.e. glacier melt water and rainwater) were investigated both spatially and temporally by hydrochemical and isotopic techniques, including analysis of major and some minor ions and O and H stable isotopes. A conceptual hydrogeological model of a fracture-diffuse flow karst groundwater aquifer was proposed. The proportion of glacier melt water infiltrating into the karst aquifer was estimated by using the karst spring as a natural pluviometer, and with stable isotope analysis. Results show that (1) the JDSM karst aquifer is a diffuse flow system; (2) it has a number of discharge areas, and the Jinsha River is the karst drainage base level; (3) the proportion of the glacier melt water penetrating the karst aquifer is 29%; and (4) the karst-related carbon sink is 26.67 ± 3.44 t km-2 a-1 (as CO2), which is lower than that in non-glacierized karst aquifers but over ten times larger than the carbon sink flux from silicate weathering in non-karst areas, showing the control of both climate and lithology on the rock weathering-related carbon sink and the significance of carbonate weathering in the global carbon cycle.

  9. A review of stormwater management in karst

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stormwater management can be a challenge in any environment, but it is especially difficult in karst terrain. The characteristic dissolution of bedrock creates depressions in topography as well as voids in the subsurface, resulting in problems such as collapse sinkhole development, groundwater cont...

  10. [Feasibility of monitoring karst standing conditions with vegetation spectra].

    PubMed

    Yue, Yue-Min; Wang, Ke-Lin; Xiong, Ying

    2012-07-01

    Karst regions are typically ecological fragile zones constrained by geological setting, which resulted in high heterogeneity of vegetation standing conditions. The karst vegetation was featured with stone, dry and high calcium carbonate content growth conditions. Based on vegetation spectral analysis and canonical correspondence analysis (CCA), the present study aimed to examine the feasibility of using vegetation spectra to monitor the heterogeneous karst standing conditions. The results showed that there were significant differences between karst vegetation and non-karst vegetation within the spectral range of 1 300-2 500 nm reflectance and 400 - 680 nm first-derivative spectra. It was found that soil moisture and calcium carbonate contents had the most significant effects on vegetation spectral features in karst regions. Ordination diagrams of CCA could distinguish the differences of karst vegetation and non-karst vegetation. Our study demonstrates that vegetation spectra are highly related to karst standing conditions and it is feasible to monitor karst standing conditions with vegetation spectral features.

  11. Structural control on karst collapse sinkhole formation

    NASA Astrophysics Data System (ADS)

    Santo, Antonio; Ascione, Alessandra; Mazzoli, Stefano; Santangelo, Nicoletta

    2013-04-01

    Collapse sinkholes owing their formation to erosion and deformation phenomena caused by subsurface karstification are widespread in the carbonate massifs of peninsular Italy. In contrast with solution dolines, which are densely distributed on the subplanar top surfaces of the carbonate massifs, the collapse sinkholes (hereinafter labelled karst collapse sinkholes) generally occur as isolated landforms and mostly affect the slopes and piedmont areas. In the latter instances, the sinkholes also affect alluvial fan conglomerates, or slope debris, overlying the carbonate rocks. We investigated the karst collapse sinkholes of the southern-central Apennines mountain belt (Italy), which is representative of a young orogenic system, characterised by recent tectonic activity and strong seismicity. The aim of the study is the identification of the causative factors which control the occurrence of such hazardous phenomena. The study was based on a regional scale analysis on sinkhole distribution in relation to the local geological-structural, geomorphological and hydrogeological contexts, and was paralleled with field analysis of some selected areas. The regional scale analysis indicates that the karst collapse sinkholes are not the mere response to the concurrence of the climatic and lithological conditions which commonly favour the development of karst processes, the occurrence of such landforms appearing strongly influenced by distinctive structural and hydrogeological conditions. In particular, a close relationship between the karst collapse sinkholes and the main extensional faults showing evidence of late Quaternary activity may be envisaged. This is inferred from the spatial distribution of the karst collapse sinkholes, which is strikingly uneven, the sinkholes generally occurring in alignments following large late Quaternary fault zones, or being clustered at the terminations of those faults. In addition, areas affected by the occurrence of groups of sinkholes, are

  12. Hydrodinamic interactions between karst conduits and matrix: some example from Classical Karst

    NASA Astrophysics Data System (ADS)

    Cucchi, F.; Boschin, W.; Visintin, L.; Zini, L.

    2009-04-01

    Karst aquifers are very different from other aquifers due to the high heterogeneity of hydraulic characteristics which leads to complex groundwater flow dynamics and storage mechanism. In this context there are some point related to practical aspects; one of this is represented from the interaction between karst conduits and matrix especially during flood events. To better understand these processes the Department of Geological, Environmental and Marine Sciences of the University of Trieste is long time studying the Classical Karst plateau. The aquifer of the Classical Karst area (about 900 km2 wide), which is divided between Italy and Slovenia, is mainly replenished by rains (1400 - 1500 mm/year). Another important contribution is given by Škocjanske Jame, a huge swallow hole which drains the waters of the Reka river (average stream flow 8 m3/s) into the karst aquifer thus feeding the hypogeal system of the Timavo river. Timavo waters flow in depth, crossing the plateau longitudinally with SE - NW direction through a system of karst conduits which develop in phreatic and epiphreatic zones with very high hydraulic transmissivity. The spring system of the aquifer is located close to the north-western section of Karst and has a mean total water discharge of 40 m3/s, 75% of which is drained by the Timavo resurgent rivers (mean discharge approximately 30 m3/s). To focused the problem several years ago a water level and water physical-chemical characteristics monitoring network was set up. This network is composed by several water point: mainly springs, many caves reaching the groundwater level and the conduit network and some piezometer affecting the karst matrix groundwater circulation with various hydraulic conductivity conditions. Collected data show that the biggest water level oscillations are often strictly connected to Reka river flood pulses. The interaction mechanism between matrix and conduits is not always the same, but it depends on the entity of the

  13. Groundwater flood hazards in lowland karst terrains

    NASA Astrophysics Data System (ADS)

    Naughton, Owen; McCormack, Ted

    2016-04-01

    The spatial and temporal complexity of flooding in karst terrains pose unique flood risk management challenges. Lowland karst landscapes can be particularly susceptible to groundwater flooding due to a combination of limited drainage capacity, shallow depth to groundwater and a high level of groundwater-surface water interactions. Historically the worst groundwater flooding to have occurred in the Rep. of Ireland has been centred on the Gort Lowlands, a karst catchment on the western coast of Ireland. Numerous notable flood events have been recorded throughout the 20th century, but flooding during the winters of 2009 and 2015 were the most severe on record, inundating an area in excess of 20km2 and causing widespread and prolonged disruption and damage to property and infrastructure. Effective flood risk management requires an understanding of the recharge, storage and transport mechanisms during flood conditions, but is often hampered by a lack of adequate data. Using information gathered from the 2009 and 2015 events, the main hydrological and geomorphological factors which influence flooding in this complex lowland karst groundwater system under are elucidated. Observed flood mechanisms included backwater flooding of sinks, overland flow caused by the overtopping of sink depressions, high water levels in turlough basins, and surface ponding in local epikarst watersheds. While targeted small-scale flood measures can locally reduce the flood risk associated with some mechanisms, they also have the potential to exacerbate flooding down-catchment and must be assessed in the context of overall catchment hydrology. This study addresses the need to improve our understanding of groundwater flooding in karst terrains, in order to ensure efficient flood prevention and mitigation in future and thus help achieve the aims of the EU Floods Directive.

  14. The water relations of trees on karst

    NASA Astrophysics Data System (ADS)

    Schwinning, S.

    2008-05-01

    The ecohydrology of karst has not received much attention, despite the disproportionally large effect that karst ecosystems might have on the availability of global freshwater quantity and quality. Theoretical considerations suggest that the ecohydrology of woody plants in karst, specifically where soil cover is thin and trees take root in the epikarst, could be very different from that of woody plants in systems with deep soils. I explore the mechanistic basis and possible ecohydrologic consequences of these differences, as well as present the results of a field study into the water relations of trees in karst. The study examined the water sources and water relations of Quercus fusiformis (Small) and Juniperus ashei (Buchholz) in the karst region of the eastern Edwards Plateau, Texas (USA). Stable isotope analysis of stem water suggested that both trees used evaporatively enriched water stored in the epikarst. Q. fusiformis had consistently higher predawn water potentials than J. ashei during drought. However, epikarst structure had strong effects on the predawn water potentials experienced during drought. Although the water potentials of both species recovered after drought- breaking rain events, associated shifts in stem water isotope ratios did not indicate significant uptake of rainwater from the shallow soil. A hypothesis is developed to explain this phenomenon invoking a piston-flow mechanism that pushes water stored in macropores into the pseudomatrix and into the presumed active root zones of the trees. The study suggests that tree species of the Edwards Plateau do not commonly reduce aquifer recharge by tapping directly into macropores or perched water tables, but more likely by reducing water storage in the pseudomatrix of the epikarst.

  15. Karst database development in Minnesota: Design and data assembly

    USGS Publications Warehouse

    Gao, Y.; Alexander, E.C.; Tipping, R.G.

    2005-01-01

    The Karst Feature Database (KFD) of Minnesota is a relational GIS-based Database Management System (DBMS). Previous karst feature datasets used inconsistent attributes to describe karst features in different areas of Minnesota. Existing metadata were modified and standardized to represent a comprehensive metadata for all the karst features in Minnesota. Microsoft Access 2000 and ArcView 3.2 were used to develop this working database. Existing county and sub-county karst feature datasets have been assembled into the KFD, which is capable of visualizing and analyzing the entire data set. By November 17 2002, 11,682 karst features were stored in the KFD of Minnesota. Data tables are stored in a Microsoft Access 2000 DBMS and linked to corresponding ArcView applications. The current KFD of Minnesota has been moved from a Windows NT server to a Windows 2000 Citrix server accessible to researchers and planners through networked interfaces. ?? Springer-Verlag 2005.

  16. Stress on tropical karst cultivated with wet rice: Bohol, Philippines

    NASA Astrophysics Data System (ADS)

    Urich, P. B.

    1993-06-01

    Wet rice cultivation represents one of the most intensive uses of tropical karst. Under wet field conditions karstlands can be highly resilient, but nevertheless vulnerable to change. The karst environment in this study has been cultivated for at least five centuries. However, the post-World War II era has fostered a host of pressures that have altered the local ecology. Resulting stress in the irrigation systems and society threaten the maintenance of this viable karst-based agricultural economy.

  17. Processes in karst systems, physics, chemistry, and geology

    SciTech Connect

    Dreybrodt, W.

    1988-01-01

    Dreybrodt deals quantitatively with many of the chemical and hydrological processes involved in the formation of karst systems. The book is divided into 3 major parts. The first part develops the basic chemical and fluid-flow principles needed in modeling karst systems. The second part investigates the experimental kinetics of calcite dissolution and precipitation and applies the resulting kinetic laws to the modeling of these processes in systems both open and closed to carbon dioxide. The last part of the book includes a qualitative examination of karst systems, quantitative modeling of the development of karst features, and an examination and modeling of the growth of spelotherms in caves.

  18. Evaporite karst of northern lower Michigan

    USGS Publications Warehouse

    Black, T.J.

    1997-01-01

    Michigan has three main zones of evaporite karst: collapse breccia in Late Silurian deposits of the Mackinac Straits region; breccia, collapse sinks, and mega-block collapse in Middle Devonian deposits of Northern Lower Michigan, which overlaps the preceding area; and areas of soil swallows in sinks of Mississippian deposits between Turner and Alabaster in Arenac and Iosco counties, and near Grand Rapids in Kent County. The author has focused his study on evaporite karst of the Middle Devonian deposits. The Middle Devonian depos its are the Detroit River Group: a series consisting of limestone, dolomite, shale, salt, gypsum, and anhydrite. The group occurs from subcrop, near the surface, to nearly 1400 feet deep from the northern tip of the Southern Peninsula to the south edge of the "solution front" Glacial drift is from zero to 350 feet thick. Oil and gas exploration has encountered some significant lost-circulation zones throughout the area. Drilling without fluid returns, casing-seal failures, and lost holes are strong risks in some parts of the region. Lost fluid returns near the top of the group in nearby areas indicate some karst development shortly after deposition. Large and irregular lost-circulation zones, linear and patch trends of large sink holes, and 0.25 mile wide blocks of down-dropped land in the northern Lower Peninsula of Michigan were caused by surface- and ground-water movement along faults into the Detroit River Group. Glaciation has removed some evidence of the karst area at the surface. Sinkhole development, collapse valleys, and swallows developed since retreat of the glacier reveal an active solution front in the Detroit River Group.

  19. Destruction of dolines: the examples from Slovene karst

    NASA Astrophysics Data System (ADS)

    Kovacic, G.; Ravbar, N.

    2012-04-01

    Due to the absence of soil and flat agricultural land, in karst regions, the cultivation of doline bottoms and the clearing of stones on fields and meadows were traditional methods of adapting farming practices to the landscape with limited agricultural potential. In recent years, a variety of activities resulting from comprehensive economic and urban development have increased pressure on karst landscapes. In some areas the surface and the underground are increasingly threatened by industrial activities, uncontrolled settlement and spread of infrastructure, the development of tourism, and intensive agrarian land use. Unsupervised human encroachment on karst landscapes is causing the increasingly more frequent and more widespread degradation of karst relief forms. The intensive reshaping of the landscape has expanded beyond control largely as a result of technological development and mechanization. The excessive modern filling of dolines, as one of the most distinctive karst surface features, has become a major encroachment on the environment for leveling purposes. Such kind of human influence affects the shape of karst features and the appearance of the landscape as well as the intensity of karst processes such as corrosion. Many dolines are filled with general and construction waste, which threatens the existence of unique habitats and quality of groundwater and consequently water supply. This contribution presents some cases of inappropriate management of karst landscape in Slovenia and examines the national legislative framework on spatial planning in karst regions. Unfortunately, in the current legislation, the standards and conditions for the protection of karst landscape characteristics (e.g. dolines) are loose and not fully elaborated. Principally, there are no uniform mechanisms to protect specific relief forms or for the adequate protection of karst. To a large extent, the preservation of the characteristic karst landscape is left to local communities

  20. International Symposium on Karst Water Resources

    NASA Astrophysics Data System (ADS)

    Back, William

    The International Association of Hydrological Sciences (IAHS) and the International Association of Hydrogeologists (IAH) joined the Hacettepe University of Ankara, Turkey, in sponsoring the International Symposium on Karst Water Resources. The other sponsors of the symposium were the Karst Water Resources Research Center Project of Hacettepe University and the United Nations Development Program through the United Nations Department of Technical Cooperation for Development, in addition to the following government organizations of Turkey: Ministry of Energy and Natural Resources, State Hydraulic, Works (DSI), General Directorate of Mineral Research and Exploration (MTA), Electrical Power Resources Survey and Development Administration (EIE) and Geological Engineering Department of the Engineering Faculty and Karst Hydrogeology Research Group (KRG) at the Hacettepe University Earth Sciences Application and Research Center. Cooperating organizations included the Turkish National Committee of the International Hydrological Program, the United Nations Educational, Scientific, and Cultural Organization (UNESCO), and the International Water Resources Association (IWRA). The symposium was divided into two parts: a paper presentation session held at the new Turkish National Library in Ankara during July 7-12, 1985, and a field trip from Ankara through Konya and Antalya to Izmir during July 13-18. The symposium chairman was Gultekin Gunay of the Hydrogeological Engineering Department of Ankara's Hacettepe University, and the cochairman was A. Ivan Johnson, a water resources consultant from Denver, Colo., and editor of WaterWatch. Scientists from 27 countries were represented among the 200 or so participants in attendance.

  1. Hypogenic karst development in a regional discharge area: Buda Thermal Karst, Hungary

    NASA Astrophysics Data System (ADS)

    Erőss, A.; Mádl-Szőnyi, J.; Csoma, A. É.

    2012-04-01

    Europe's largest naturally flowing thermal water system can be found in Budapest. The springs and wells that supply the famous baths of Budapest discharge from a regional Triassic carbonate rock aquifer system. As the result of the interaction of discharging waters and carbonate rocks, extensive cave systems has developed and still developing today. These caves belong to the group of hypogenic caves, and their special morphology and peculiar minerals make Budapest, beside the city of spas, also "the capital of caves". According to the recent developments in the speleogenetic theories, hypogenic karsts and caves are viewed in flow system context, and can thus be considered as the manifestations of flowing groundwater. Being a marginal area at the boundary of uplifted carbonates and a sedimentary basin, the Buda Thermal Karst serves as a discharge zone of the regional fluid flow. This implies that it may receive fluid components (karstic and basinal) from several sources resulting in a wide range of discharge features including springs, caves, and mineral precipitates. In this study the discharge areas of the Buda Thermal Karst were investigated to determine how the discharging fluids and adjoining phenomena (e.g. caves, mineral precipitates) can be telltales of their parent fluid systems, the processes acting along the flow path and operating directly at the vicinity of the discharge zone. A comprehensive hydrogeological study was carried out for the investigation of these phenomena and for the characterization of processes acting today at the discharge zone of the Buda Thermal Karst. Methods included hydrogeochemical, mineralogical and microbiological investigations. Among the results of the study, several processes were identified which can be responsible for cave development and formation of minerals, among them mixing corrosion and microbially mediated sulphuric acid speleogenesis have crucial role. Furthermore, the role of the adjacent sedimentary basin was

  2. Evaluating the anthropogenic impact on karst environments: Karst Disturbance Index applied to West-Central Florida and Southeast Italy

    NASA Astrophysics Data System (ADS)

    North, L. A.; Parise, M.; van Beynen, P. E.

    2009-04-01

    Due to its high fragility, that derives from the intrinsic geological and hydrogeological characteristics, karst is extremely vulnerable to degradation and pollution. Although the carrying capacity of these natural environments is low, a variety of human activities is implemented on karst settings generating impacts at the surface and subsurface. The human-induced effects in karst can be assessed by applying a recently developed Karst Disturbance Index (KDI). The KDI consists of 31 environmental indicators contained within the five broad categories: geomorphology, hydrology, atmosphere, biota, and cultural. The purpose of this research is to apply the KDI to two distinct karst areas, West Florida, USA, and Apulia, Southeast Italy. Through its application, the utility of the index can be validated and other important comparisons can be made, such as differences in the karst legislations implemented in each region and the effect of time exposure to human occupation to each karst terrain. Humans have intensively impacted the karst of southeast Italy for thousands of years compared to only decades in west-central Florida. However, west-central Florida's higher population density allows the region to reach disturbance levels comparable to those reached over a longer period in Apulia. Similarly, Italian karst is more diverse than the karst found in west-central Florida, creating an opportunity to test all the KDI indicators. Overall, major disturbances for southeast Italy karst include quarrying, stone clearing, and the dumping of refuse into caves, while west-central Florida suffers most from the infilling of sinkholes, soil compaction, changes in the water table, and vegetation removal. The application of the KDI allows a benchmark of disturbance to be established and later revisited to determine the changing state of human impact for a region. The highlighting of certain indicators that recorded high levels of disturbance also allows regional planners to allocate

  3. Evaporite-karst problems and studies in the USA

    NASA Astrophysics Data System (ADS)

    Johnson, Kenneth S.

    2008-01-01

    Evaporites, including rock salt (halite) and gypsum (or anhydrite), are the most soluble among common rocks; they dissolve readily to form the same types of karst features that commonly are found in limestones and dolomites. Evaporites are present in 32 of the 48 contiguous states in USA, and they underlie about 40% of the land area. Typical evaporite-karst features observed in outcrops include sinkholes, caves, disappearing streams, and springs, whereas other evidence of active evaporite karst includes surface-collapse structures and saline springs or saline plumes that result from salt dissolution. Many evaporites also contain evidence of paleokarst, such as dissolution breccias, breccia pipes, slumped beds, and collapse structures. All these natural karst phenomena can be sources of engineering or environmental problems. Dangerous sinkholes and caves can form rapidly in evaporite rocks, or pre-existing karst features can be reactivated and open up (collapse) under certain hydrologic conditions or when the land is put to new uses. Many karst features also propagate upward through overlying surficial deposits. Human activities also have caused development of evaporite karst, primarily in salt deposits. Boreholes (petroleum tests or solution-mining operations) or underground mines may enable unsaturated water to flow through or against salt deposits, either intentionally or accidentally, thus allowing development of small to large dissolution cavities. If the dissolution cavity is large enough and shallow enough, successive roof failures can cause land subsidence and/or catastrophic collapse. Evaporite karst, natural and human-induced, is far more prevalent than is commonly believed.

  4. 76 FR 61379 - Final Recovery Plan, Bexar County Karst Invertebrates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... Bexar County karst invertebrates were listed as endangered species on December 26, 2000 (65 FR 81419... Fish and Wildlife Service Final Recovery Plan, Bexar County Karst Invertebrates AGENCY: Fish and... Invertebrates under the Endangered Species Act of 1973, as amended (Act). These species occur in Bexar...

  5. Contaminant transport in two central Missouri karst recharge areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst watersheds with significant losing streams represent a particularly vulnerable setting for ground water contamination because of the direct connection to surface water. Because of the existing agricultural land-use and future likelihood of urbanization, two losing stream karst basins were chos...

  6. Informal Karst Education in the United States and Internationally

    ERIC Educational Resources Information Center

    North, Leslie A.

    2011-01-01

    Despite the abundance of karst terrains and the important role they play in a wide variety of roles including supplying freshwater drinking supplies, no single, comprehensive study investigates the role of informal education for the improved understanding and protection of the terrains. Commonly overlooked anthropogenic karst disturbances…

  7. Karst mapping in the United States: past, present and future

    USGS Publications Warehouse

    Weary, David J.; Doctor, Daniel H.

    2015-01-01

    The earliest known comprehensive karst map of the entire USA was published by Stringfield and LeGrand (1969), based on compilations of William E. Davies of the U.S. Geological Survey (USGS). Various versions of essentially the same map have been published since. The USGS recently published new digital maps and databases depicting the extent of known karst, potential karst, and pseudokarst areas of the United States of America including Puerto Rico and the U.S. Virgin Islands (Weary and Doctor, 2014). These maps are based primarily on the extent of potentially karstic soluble rock types, and rocks with physical properties conducive to the formation of pseudokarst features. These data were compiled and refined from multiple sources at various spatial resolutions, mostly as digital data supplied by state geological surveys. The database includes polygons delineating areas with potential for karst and that are tagged with attributes intended to facilitate classification of karst regions. Approximately 18% of the surface of the fifty United States is underlain by significantly soluble bedrock. In the eastern United States the extent of outcrop of soluble rocks provides a good first-approximation of the distribution of karst and potential karst areas. In the arid western states, the extent of soluble rock outcrop tends to overestimate the extent of regions that might be considered as karst under current climatic conditions, but the new dataset encompasses those regions nonetheless. This database will be revised as needed, and the present map will be updated as new information is incorporated.

  8. Verification of the karst flow model under laboratory controlled conditions

    NASA Astrophysics Data System (ADS)

    Gotovac, Hrvoje; Andric, Ivo; Malenica, Luka; Srzic, Veljko

    2016-04-01

    Karst aquifers are very important groundwater resources around the world as well as in coastal part of Croatia. They consist of extremely complex structure defining by slow and laminar porous medium and small fissures and usually fast turbulent conduits/karst channels. Except simple lumped hydrological models that ignore high karst heterogeneity, full hydraulic (distributive) models have been developed exclusively by conventional finite element and finite volume elements considering complete karst heterogeneity structure that improves our understanding of complex processes in karst. Groundwater flow modeling in complex karst aquifers are faced by many difficulties such as a lack of heterogeneity knowledge (especially conduits), resolution of different spatial/temporal scales, connectivity between matrix and conduits, setting of appropriate boundary conditions and many others. Particular problem of karst flow modeling is verification of distributive models under real aquifer conditions due to lack of above-mentioned information. Therefore, we will show here possibility to verify karst flow models under the laboratory controlled conditions. Special 3-D karst flow model (5.6*2.6*2 m) consists of concrete construction, rainfall platform, 74 piezometers, 2 reservoirs and other supply equipment. Model is filled by fine sand (3-D porous matrix) and drainage plastic pipes (1-D conduits). This model enables knowledge of full heterogeneity structure including position of different sand layers as well as conduits location and geometry. Moreover, we know geometry of conduits perforation that enable analysis of interaction between matrix and conduits. In addition, pressure and precipitation distribution and discharge flow rates from both phases can be measured very accurately. These possibilities are not present in real sites what this model makes much more useful for karst flow modeling. Many experiments were performed under different controlled conditions such as different

  9. Occurrence and dynamics of micropollutants in a karst aquifer.

    PubMed

    Morasch, Barbara

    2013-02-01

    Karst systems represent important yet vulnerable drinking water resources. A wide spectrum of pollutants may be released into karst groundwater from agriculture, livestock farming, private households, and industry. This work provides an overview on the occurrence and dynamics of micropollutants in a karst system of the Swiss Jura. Ten months of intensive monitoring for micropollutants confirmed that the swallow hole draining an agricultural plain was the main entry path for pesticides into the karst system and the two connected springs. Elevated fungicide concentrations in winter and occasional quantification of pharmaceuticals suggested wood- or façade treatment and domestic sewer as additional sources of contamination. A continuous atrazine signal in the low ng/L range might affect the autochthonous endokarst microbial community and represents a potential risk for the human population through karst groundwater.

  10. Occurrence and dynamics of micropollutants in a karst aquifer.

    PubMed

    Morasch, Barbara

    2013-02-01

    Karst systems represent important yet vulnerable drinking water resources. A wide spectrum of pollutants may be released into karst groundwater from agriculture, livestock farming, private households, and industry. This work provides an overview on the occurrence and dynamics of micropollutants in a karst system of the Swiss Jura. Ten months of intensive monitoring for micropollutants confirmed that the swallow hole draining an agricultural plain was the main entry path for pesticides into the karst system and the two connected springs. Elevated fungicide concentrations in winter and occasional quantification of pharmaceuticals suggested wood- or façade treatment and domestic sewer as additional sources of contamination. A continuous atrazine signal in the low ng/L range might affect the autochthonous endokarst microbial community and represents a potential risk for the human population through karst groundwater. PMID:23202643

  11. A remote sensing study of regional variation in sinkhole morphology-Florida karst vs. Minnesota karst

    NASA Astrophysics Data System (ADS)

    Ernst, C. L.; Hadizadeh, J.; McCarty, J. L.

    2010-12-01

    In many regions of the United States, database technologies and GIS have facilitated spatial analysis of karst. The purpose of this research was to compare regional latitudinal variation in sinkhole karst morphology via remote sensing techniques. Such comparison may be significant because the development of a karst landscape depends primarily on climate and availability of water as well as lithology. Sinkhole karst, a common karst in the U.S., is morphologically defined as cone-shaped depressions with circular or oval opening to the surface that result from the dissolution of relatively soluble bedrock such as limestone or gypsum. The two regions of interest, north-central Florida and southeastern Minnesota, were selected based on structural and lithological similarity of limestone bedrock and the fact that the bedrock study areas are located in clearly different climate zones. This approach utilized topographic maps, digital elevation models, state karst feature databases, and high resolution 0.6m QuickBirdTM and 0.5m WorldView 1TM satellite images in a GIS environment. Morphological parameters - area, perimeter, minor axis and major axis length - were calculated on a total of 80 sinkholes in the study regions using the zonal geometry function, a tool in the spatial analysis extension provided by ESRITM. Our results show that north-central Florida and southeastern Minnesota karst are statistically different in terms of sinkhole shape and size distribution. Florida has larger sinkholes (2,835 square meter Mean) that are closer to circular shape. Minnesota has smaller (1,213 square meter Mean) and more elliptical sinkholes with a comparatively shorter minor axis. Of the possible explanations, climate appears to be the most likely cause for the observed differences. The higher amount of precipitation in Florida coupled with warmer year round temperatures provides an environment conducive to a more chemically involved hydrological regime, which may be responsible for

  12. Geomorphological significance of the palaeodrainage network on a karst plateau: The Una-Korana plateau, Dinaric karst, Croatia

    NASA Astrophysics Data System (ADS)

    Bočić, Neven; Pahernik, Mladen; Mihevc, Andrej

    2015-10-01

    Karst plateaus often have a complex geological and geomorphological history. It is widely accepted that their development requires a long period of karst denudation. This study reconstructs the palaeodrainage network of a karst plateau, analyses its properties and establishes its geomorphological significance. The main purpose of this research was to deepen our understanding of a key stage in the evolution of karst plateaus - the transition from a fluvial land surface to one dominated by karst surface processes. The study was conducted on a large part of the Una-Korana plateau, the largest plateau in the Dinaric karst. The majority of the plateau is made of carbonate rocks of Triassic, Jurassic and Cretaceous age that set the conditions for the development of the karst. We have reconstructed the palaeodrainage network based on 1:25,000 topographic maps with 10 m contours. The transition of the surface drainage network to the underground karst drainage network is still in progress, so, depending on the degree of karstification, the drainage network was divided into three categories: active, dry and relict. It was found that 90.5% of the pre-existing drainage network has undergone some degree of karstification. The active surface drainage network gradually shifted to a dry network, then to a relict network. The surface drainage network is gradually replaced by a dense network of dolines. Today, the flat and karstified inter-fluvial area is drained underground towards the main watercourses and these drain the entire region over the surface towards the Pannonian basin. This is the largest known karst palaeodrainage network in the Dinaric karst that has been reconstructed in this way.

  13. Karst on Mars? The thumbprint terrain

    NASA Technical Reports Server (NTRS)

    Schaefer, Martha W.

    1990-01-01

    The nature of the 'thumbprint' terrain noted by Guest et al. (1977) in high-resolution Viking Orbiter photographs of the northern plains of Mars is considered in light of plausible terrestrial analogs. At least some portion of such terrain may be due to differential solution of large carbonate deposits located in low-lying areas; comparative morphology may therefore indicate it to be an analog of the arid karst of Australia's Nullabor Plain, provided that groundwater flow was available during the terrain's formative period on Mars.

  14. Research approach to teaching groundwater biodegradation in karst aquifers

    USGS Publications Warehouse

    King, L.; Byl, T.; Painter, R.

    2006-01-01

    TSU in partnership with the USGS has conducted extensive research regarding biode??gradation of contaminants in karst aquifers. This research resulted in the development of a numerical approach to modeling biodegradation of contaminants in karst aquifers that is taught to environmental engineering students in several steps. First, environmental engineering students are taught chemical-reaction engineering principles relating to a wide variety of environmental fate and transport issues. Second, as part of TSU's engineering course curriculum, students use a non-ideal flow laboratory reactor system and run a tracer study to establish residence time distribution (RTD). Next, the students couple that formula to a first-order biodegradation rate and predict the removal of a biodegradable contaminant as a function of residence time. Following this, students are shown data collected from karst bedrock wells that suggest that karst aquifers are analogous to non-ideal flow reactors. The students are challenged to develop rates of biodegradation through lab studies and use their results to predict biodegradaton at an actual contaminated karst site. Field studies are also conducted to determine the accuracy of the students' predictions. This academic approach teaches biodegradation processes, rate-kinetic processes, hydraulic processes and numerical principles. The students are able to experience how chemical engineering principles can be applied to other situations, such as, modeling biodegradation of contaminants in karst aquifers. This paper provides background on the chemical engineering principles and karst issues used in the research-enhanced curriculum. ?? American Society for Engineering Education, 2006.

  15. Spatial distribution of nitrogen on grazed karst landscapes.

    PubMed

    Boyer, D G; Alloush, G A

    2001-11-27

    The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian region. Karst areas comprise about 18% of the region"s land area. An estimated one-third of the region"s farms, cattle, and agricultural market value are located on karst terrain. Mean nitrate concentrations in several karst springs in southeastern West Virginia exhibit a strong linear relationship with the percentage of agriculture land cover. Development of best management practices for efficient nitrogen (N) use and reduction of outflow of N to water from karst areas requires knowledge about N dynamics on those landscapes. Water extractable NO3-N and NH4-N were measured along transects at four soil depths in two grazed sinkholes and one wooded sinkhole. Distribution of soil NO3-N and NH4-N were related to frequency of animal presence and to topographic and hydrologic redistribution of soil and fecal matter in the grazed sinkholes. Karst pastures are characterized by under drainage and funneling of water and contaminants to the shallow aquifer. Control of NO3-N leaching from karst pasture may depend on management strategies that change livestock grazing behavior in sinkholes and reduce the opportunity for water and contaminants to quickly reach sinkhole drains.

  16. Thermal Signals as a Means of Characterizing Karst Aquifers

    NASA Astrophysics Data System (ADS)

    Covington, M. D.; Luhmann, A. J.; Alexander, E. C.; Alexander, S. C.; Saar, M. O.; Wicks, C. M.

    2009-12-01

    Karst springs display a wide variety of thermal behaviors, from quick responses during transient flow, to seasonal variations, to constant temperature. Since temperature is a reactive tracer, it carries information about both the nature of aquifer recharge and the geometry of the flow path taken. We use a combination of analytical, numerical, and field techniques to elucidate the fundamental types of thermal responses of karst aquifers, and to explore the connections between these responses and the recharge and geometry of the system. In particular, we derive a thermal penetration length, which describes the distance over which a temperature signal will decay while propagating through a karst aquifer. Calculation of this penetration length for typical parameter ranges of the various components of a karst aquifer (conduits, fractures, and matrix) enables some generalizations about the typical thermal response of each of these components. The theoretical work is combined with a field study of a number of karst aquifers in southeastern Minnesota, an ideal region for study of heat transport in karst because of its extreme seasonal surface temperature variations. We deploy five data loggers along a single cave stream to record thermal signals as they propagate down the system. Since the geometry of the main flow path is known, we can make explicit connections between the signal propagation and conduit geometry. We also deploy temperature sensors at about twenty karst springs throughout the region to sample the possible range of temperature signals. We interpret the variety of thermal patterns observed within the theoretical framework described above.

  17. Gypsum-karst problems in constructing dams in the USA

    NASA Astrophysics Data System (ADS)

    Johnson, Kenneth S.

    2008-01-01

    Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30-60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US 12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming.

  18. Gypsum-karst problems in constructing dams in the USA

    USGS Publications Warehouse

    Johnson, K.S.

    2008-01-01

    Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30-60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US $12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming. ?? 2007 Springer-Verlag.

  19. Karst geomorphology: From hydrological functioning to palaeoenvironmental reconstructions. Part II

    NASA Astrophysics Data System (ADS)

    De Waele, Jo; Gutierrez, Francisco; Audra, Philippe

    2015-10-01

    In January 2015, the first part of the special issue on karst, entitled "Karst geomorphology: From hydrological functioning to palaeoenvironmental reconstructions" was published (Geomorphology, Vol. 229). This second part of the special issue comprises seven research papers covering a broad geographical canvas including Japan, Slovenia, France, Spain, Croatia, and Poland-Ukraine. Both issues mainly emanate from the contributions presented in the Karst session of the 8th International Conference of Geomorphology (International Association of Geomorphologists), held in Paris in August 2013, enriched with some invited papers.

  20. Maya utilization of karst groundwater resources

    NASA Astrophysics Data System (ADS)

    Veni, George

    1990-07-01

    Much of the Maya civilization in pre-Columbian Meso-America was established on karst terrain that included parts of what are now Belize, Guatemala, northern Honduras and southern Mexico. By definition, little surface water exists in karst, so for the Maya to flourish on that terrain they had to effectively and efficiently utilize all their water resources. Access to groundwater was by means of springs and caves. Maya life, urban and rural, lay and elite, religious and secular was often a function of groundwater exploitation and surface water development. The Maya's use of groundwater was predominantly to supplement enhanced surface water supplies and was used more often in semiarid zones than in humid zones. The pattern of Maya settlements, especially in the semiarid zones, occurred in areas with greater access to the groundwater. Maya groundwater retrieval methods were primitive, inefficient, labor intensive, and uninnovative, as compared to their other technologic achievements. Groundwater contamination, from human effluent, could have resulted in widespread disease and contributed to the Maya's downfall.

  1. South Texas Quaternary karst: Paleoclimatic implications

    SciTech Connect

    Prouty, J.S. ); Lovejoy, D.W. )

    1993-02-01

    A beachrock correlative with the Ingleside complex of the late Pleistocene Beaumont Formation crops out discontinuously along the mainland shore of Laguna Madre, extending approximately 10 km southward from Baffin Bay, Texas. Carbon-14 dating yields ages of 23, 430 to 33,390 yrs. B.P.; the beachrock formed along a Gulf shoreline in a zone of converging longshore currents during the last sea level highstand of the late Wisconsinan. The beachrock shows intense karstification. Vertical, steep-walled solution pipes penetrate the outcrops, and reddish-brown laminated caliche crusts coat outcrop surfaces and solution-pipe walls in many places. These karst features probably formed by subaerial exposure and weathering of the beachrock during the latest sea level lowstand. Today in semiarid South Texas, rainfall averages only 28 inches per year. Local features of late Pleistocene age include river gravels coarser than modern loads of those same rivers, and relict drainage networks far denser than modern ones. Such features indicate that during the late Pleistocene this region was more humid than now. Karst is typical of humid to subhumid climates, also suggesting that during karstification of the beachrock wetter climates prevailed.

  2. Contamination investigation in a karst region

    SciTech Connect

    Bentowski, J.E. )

    1993-03-01

    A series of springs in the karst region of north central Kentucky appeared to have been contaminated. These springs are within 1/2 mile of two sinkholes which were filled-in as permitted landfills for inert waste and then developed into an industrial park. A pre-remedial site inspection was performed under the authority of the Superfund laws in late 1989. A preliminary site visit included site reconnaissance and geologic field work to locate the springs. A review of historical serial photos aided in the planning the investigation program consisting of magnetic and soil gas surveys and the taking environmental soil and water samples. The soil gas survey indicated potential soil sampling locations. Seventeen surface and subsurface soil samples were taken. Eleven water samples were taken from various springs, rivers and the local public water supply. The analytical results from soil samples taken over the largest sinkhole matched nine inorganic and eleven volatile organic compounds also found in the spring water and sediment samples. The springs are roughly on strike with major fracture systems reported in the literature. The success of this investigation emphasizes the importance of proper geologic consideration for contaminant monitoring in karst regions.

  3. Karst groundwater: a challenge for new resources

    NASA Astrophysics Data System (ADS)

    Bakalowicz, Michel

    2005-03-01

    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 m3/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 suc h as the void structure - only a conduit network, or a conduit network plus a porous matrix -, the functioning - threshold effects and non-linearities -, 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. Los acuíferos kársticos tienen características originales y complejas que los hacen muy diferentes de otros acuíferos: alta heterogeneidad creada y organizada por el flujo de agua subterránea, espacios grandes, velocidades altas de flujo de hasta varios cientos de m/h, manantiales con ritmo alto de flujo de hasta algunas decenas de m3/s. Diferentes modelos conceptuales que se conocen en la literatura tratan de tomar en cuenta todas estas particularidades. Los métodos de estudio usados en hidrogeología clásica- pozos, pruebas de bombeo y modelos distribuidos- son generalmente inválidos y no exitosos en acu

  4. Gypsum karst in Italy: a review

    NASA Astrophysics Data System (ADS)

    De Waele, Jo; Chiarini, Veronica; Columbu, Andrea; D'Angeli, Ilenia M.; Madonia, Giuliana; Parise, Mario; Piccini, Leonardo; Vattano, Marco; Vigna, Bartolomeo; Zini, Luca; Forti, Paolo

    2016-04-01

    Although outcropping only rarely in Italy, gypsum karst has been described in detail since the early XXth century (Marinelli, 1917). Gypsum caves are now known from almost all Italian regions (Madonia & Forti, 2003), but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche regions), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum quarries in Piedmont (Vigna et al., 2010). During the late 80s and 90s several multidisciplinary studies have been carried out in many gypsum areas. All this work converged into a comprehensive overview in 2003 (Madonia & Forti, 2003). Further detailed studies focused on the gypsum areas of Emilia Romagna (Chiesi et al., 2010; Forti & Lucci, 2010; Demaria et al., 2012; De Waele & Pasini, 2013; Ercolani et al., 2013; Columbu et al., 2015; Lucci & Piastra, 2015; Tedeschi et al., 2015) and of Sicily (Madonia & Vattano, 2011). Sinkholes related to Permo-Triassic gypsum have been studied in Friuli Venezia Giulia (Zini et al., 2015). This presentation will review the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results. References Chiesi M., et al. (2010) - Origin and evolution of a salty gypsum/anhydrite karst spring: the case of Poiano (Northern Apennines, Italy). Hydrogeology Journal, 18, pp. 1111-1124. Columbu A. et al. (2015) - Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region. Geology, 43(6), 539-542. Demaria D. et al. (Eds.) (2012), Le Grotte Bolognesi, GSB-USB, 431 p. De Waele J., Pasini G. (2013) - Intra-messinian gypsum palaeokarst in the northern Apennines and its palaeogeographic implications. Terra Nova 25, pp. 199-205. Ercolani M., et al. (Eds.) (2013), I Gessi e la Cave i Monte Tondo. Studio multidisciplinare di un'area carsica nella Vena del Gesso Romagnola. Memorie Ist. It. Spel. II(26), 559 p

  5. Climate, karst, and critters—A multidisciplinary evaluation of karst species vulnerability to climate change

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Musgrove, M.; Long, A. J.; Stamm, J. F.; Poteet, M. F.; Symstad, A.

    2015-12-01

    The complex hydrologic regimes of karst aquifers respond rapidly to the effects of climate change, and unique biological communities associated with karst are sensitive to hydrologic changes. To explore how climate change might affect karst-dependent species, we coupled a climate-change model, a hydrologic model, and a vulnerability assessment tool to evaluate projected hydrologic change and vulnerability of selected species at sites in the karstic Edwards aquifer (Texas) and Madison aquifer (South Dakota). The Advanced Research Weather and Research Forecasting (WRF) model was used to simulate projected climate from 2011 to 2050 at a 36-km grid spacing for 3 weather stations near the study sites. Daily climate projections from the WRF model were used as input for the hydrologic Rainfall-Response Aquifer and Watershed Flow (RRAWFLOW) model and the Climate Change Vulnerability Index (CCVI). RRAWFLOW is a lumped-parameter model that simulates hydrologic response at a single site, superposing the quick- and slow-flow responses that commonly characterize karst aquifers. CCVI uses historical and projected climate and hydrologic metrics to assess the vulnerability of a species. An upward trend in temperature was projected at all three weather stations; there was a trend (downward) in precipitation only for the Texas weather station. A downward trend in mean annual spring flow or groundwater level was projected for the three Edwards sites, but there was no significant trend for the two Madison sites. Of 16 Edwards aquifer species evaluated, 10 were scored as highly or moderately vulnerable under the projected climate change scenario. In contrast, all 8 Madison aquifer species evaluated were scored as moderately vulnerable, stable, or intermediate between the two. The inclusion of hydrologic projections in the vulnerability assessment was essential for interpreting the effects of climate change on aquatic species of conservation concern such as endemic salamanders.

  6. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida.

    PubMed

    Xu, Zexuan; Bassett, Seth Willis; Hu, Bill; Dyer, Scott Barrett

    2016-01-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 11 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This paper documents the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer. PMID:27557803

  7. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida.

    PubMed

    Xu, Zexuan; Bassett, Seth Willis; Hu, Bill; Dyer, Scott Barrett

    2016-08-25

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 11 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This paper documents the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

  8. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida

    NASA Astrophysics Data System (ADS)

    Xu, Zexuan; Bassett, Seth Willis; Hu, Bill; Dyer, Scott Barrett

    2016-08-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 11 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This paper documents the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

  9. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida

    PubMed Central

    Xu, Zexuan; Bassett, Seth Willis; Hu, Bill; Dyer, Scott Barrett

    2016-01-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 11 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This paper documents the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer. PMID:27557803

  10. Exploring a contagion model for karst terrane evolution

    SciTech Connect

    Kemmerly, P.R.

    1985-01-01

    The theoretical and geomorphic implications of a contagion model of karst depression and initiation are explored with particular emphasis on (1) identifying the parent versus daughter depression subpopulations; (2) analyzing the spatial characteristics of each subpopulation; and (3) defining the contagious karst mechanism and hot it is transmitted along solution-enlarged joints. The contagious karst mechanism suggests that the presence of one or more parent depressions does increase the the probability of daughter depressions developing along solution-enlarged joints that radiate outward from beneath parent depressions. In karst terranes where the contagious model applies, a well defined infrastructure exists with several important elements. The interaction of these elements in the infrastructure result in depressions occurring in clusters. The clusters tend to be randomly distributed and consist typically of a centrally located parent depression surrounded by numerous daughter depressions.

  11. [Dissolved organic matter (DOM) dynamics in karst aquifer systems].

    PubMed

    Yao, Xin; Zou, Sheng-Zhang; Xia, Ri-Yuan; Xu, Dan-Dan; Yao, Min

    2014-05-01

    Dissolved organic matter (DOM) and nutrients have a unique way of producing, decomposing and storing in southwest karst water systems. To understand the biogeochemical cycle of DOM in karst aquifer systems, we investigated the behavioral changes of DOM fluorescence components in Zhaidi karst river system. Two humic-like components (C1 and C2), and one autochthonous tyrosine-like component (C4) were identified using the parallel factor analysis (PARAFAC) model. Compared with the traditional physical and chemical indicators, spatial heterogeneity of DOM was more obvious, which can reflect the subtle changes in groundwater system. Traditional indicators mainly reflect the regional characteristics of karst river system, while DOM fluorescence components reflect the attribute gaps of sampling types.

  12. Detection of karst structures using airborne EM and VLF

    SciTech Connect

    Beard, L.P. Nyquist, J.E.; Carpenter, P.J.

    1994-12-31

    Through the combined use of multi-frequency helicopter electromagnetic and VLF data, it is possible to detect and delineate a wide variety of karst structures and possibly to assess their interconnectedness. Multi-frequency EM Can detect karst features if some element of the structure is conductive. This conductive aspect may derive from thick, moist soils in the depression commonly associated with a doline, from conductive fluids in the cavity, or from conductive sediments in the cavity if these occupy a significant portion of it. Multiple loop configurations may also increase the likelihood of detecting karst features. Preliminary evidence indicates total field VLF measurements may be able to detect interconnected karst pathways, so long as the pathways are water or sediment filled. Neither technique can effectively detect dry, resistive air-filled cavities.

  13. Karst groundwater: a challenge for new resources

    NASA Astrophysics Data System (ADS)

    Bakalowicz, Michel

    2005-03-01

    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 m3/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 suc h as the void structure - only a conduit network, or a conduit network plus a porous matrix -, the functioning - threshold effects and non-linearities -, 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. Los acuíferos kársticos tienen características originales y complejas que los hacen muy diferentes de otros acuíferos: alta heterogeneidad creada y organizada por el flujo de agua subterránea, espacios grandes, velocidades altas de flujo de hasta varios cientos de m/h, manantiales con ritmo alto de flujo de hasta algunas decenas de m3/s. Diferentes modelos conceptuales que se conocen en la literatura tratan de tomar en cuenta todas estas particularidades. Los métodos de estudio usados en hidrogeología clásica- pozos, pruebas de bombeo y modelos distribuidos- son generalmente inválidos y no exitosos en acu

  14. Evaporite-karst problems and studies in the USA

    USGS Publications Warehouse

    Johnson, K.S.

    2008-01-01

    Evaporites, including rock salt (halite) and gypsum (or anhydrite), are the most soluble among common rocks; they dissolve readily to form the same types of karst features that commonly are found in limestones and dolomites. Evaporites are present in 32 of the 48 contiguous states in USA, and they underlie about 40% of the land area. Typical evaporite-karst features observed in outcrops include sinkholes, caves, disappearing streams, and springs, whereas other evidence of active evaporite karst includes surface-collapse structures and saline springs or saline plumes that result from salt dissolution. Many evaporites also contain evidence of paleokarst, such as dissolution breccias, breccia pipes, slumped beds, and collapse structures. All these natural karst phenomena can be sources of engineering or environmental problems. Dangerous sinkholes and caves can form rapidly in evaporite rocks, or pre-existing karst features can be reactivated and open up (collapse) under certain hydrologic conditions or when the land is put to new uses. Many karst features also propagate upward through overlying surficial deposits. Human activities also have caused development of evaporite karst, primarily in salt deposits. Boreholes (petroleum tests or solution-mining operations) or underground mines may enable unsaturated water to flow through or against salt deposits, either intentionally or accidentally, thus allowing development of small to large dissolution cavities. If the dissolution cavity is large enough and shallow enough, successive roof failures can cause land subsidence and/or catastrophic collapse. Evaporite karst, natural and human-induced, is far more prevalent than is commonly believed. ?? 2007 Springer-Verlag.

  15. Karst collapse in cities and mining areas, China

    SciTech Connect

    Jian Chen )

    1988-08-01

    Karst collapse is a dynamic geological phenomenon, in which the rock mass or deposits overlying the karstified zone subsides down along the karst cavity, resulting in a collapse pit or sinkhole. After discussing the typical examples of collapse emerging in the karst cities and mines in provinces and regions of South China, such as Guangdong, Guangxi, Hunan, Hubei, Zhejiang, Yunnan, Guizhou, and Jiangxi, it is considered that human activities of economy and production have become a major effect in causing karst collapse. Man-made collapses make 66.4 percent of the total, whereas natural ones 33.6 percent. Most of the collapses occurred to the area with soil overburden (96.7 percent), only a few in areas of bedrock overburden (3.3 percent). The karst collapses have a close relationship with the extent of karst development, the character and the thickness of overburden, and the dynamic condition of underground water. Collapse usually occurs in those parts of an area that are more intensely karstified, with soil thickness less than 5 m and a high amplitude of water table fluctuation. Many kinds of mechanical effects are caused by pumping or draining on the over-burden and destroying its equilibrium, leading to the collapse. These effects included the support loss and load-added effect, penetrating suffusion, gas explosion, water-hammer, suction pressure erosion, and liquefaction effects. The collapses are the result of varied comprehensive effects, particularly the support loss and load-added, and penetrating suffusion.

  16. Management Can Reduce Mobility of Escherichia coli compared to traditional groundwater tracers within karst terrains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An understanding of fundamental processes controlling pathogen movement is necessary to protect water resources across the globe. Limited filtration and turbulent flow make karst aquifers susceptible to microbial contamination. Groundwater tracers typically used in karst terrains include fluorescent...

  17. FATE AND TRANSPORT OF PETROLEUM RELEASED FROM UNDERGROUND STORAGE TANKS in Areas of Karst Topography

    EPA Science Inventory

    The study determines the transport and ultimate fate of petroleum products within a region of karst geomorphology. The paper entails a complete literature review, including references that pertain to contaminant transport within karst aquifers

  18. Karst rocky desertification information extraction with EO-1 Hyperion data

    NASA Astrophysics Data System (ADS)

    Yue, Yuemin; Wang, Kelin; Zhang, Bing; Jiao, Quanjun; Yu, Yizun

    2008-12-01

    Karst rocky desertification is a special kind of land desertification developed under violent human impacts on the vulnerable eco-geo-environment of karst ecosystem. The process of karst rocky desertification results in simultaneous and complex variations of many interrelated soil, rock and vegetation biogeophysical parameters, rendering it difficult to develop simple and robust remote sensing mapping and monitoring approaches. In this study, we aimed to use Earth Observing 1 (EO-1) Hyperion hyperspectral data to extract the karst rocky desertification information. A spectral unmixing model based on Monte Carlo approach, was employed to quantify the fractional cover of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare substrates. The results showed that SWIR (1.9-2.35μm) portions of the spectrum were significantly different in PV, NPV and bare rock spectral properties. It has limitations in using full optical range or only SWIR (1.9-2.35μm) region of Hyperion to decompose image into PV, NPV and bare substrates covers. However, when use the tied-SWIR, the sub-pixel fractional covers of PV, NPV and bare substrates were accurately estimated. Our study indicates that the "tied-spectrum" method effectively accentuate the spectral characteristics of materials, while the spectral unmixing model based on Monte Carlo approach is a useful tool to automatically extract mixed ground objects in karst ecosystem. Karst rocky desertification information can be accurately extracted with EO-1 Hyperion. Imaging spectroscopy can provide a powerful methodology toward understanding the extent and spatial pattern of land degradation in karst ecosystem.

  19. Use of stable isotope-labeled Escherichia coli as a tracer in karst aquifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial contamination of karst aquifers is a large concern across the globe, yet bacterial transport in karst aquifers is not currently well understood. Groundwater tracers typically used in karst systems include fluorescent dyes and latex microspheres. Not only can these tracers can be cost-prohi...

  20. Karst catchments exhibited higher degradation stress from climate change than the non-karst catchments in southwest China: An ecohydrological perspective

    NASA Astrophysics Data System (ADS)

    Liu, Meixian; Xu, Xianli; Wang, Dingbao; Sun, Alexander Y.; Wang, Kelin

    2016-04-01

    Karst landform represents about 10% of the continental area and plays key roles in water supplies for almost a quarter of the global population. Knowledge of ecohydrological responses of karst landform to climate change is critical for both water resources management and ecological protection in these regions. This study investigated the effects of karst landform on the elasticity of actual evapotranspiration (derived by the Budyko equation), estimated the contribution of climate change and evaluated the implications, on the basis of 13 typical catchments that have different karst landform coverages in southwest China. Catchment properties, including the vegetation coverage, portion of karst landform (POK), drainage area, surface roughness, mean topographic wetness index, mean slope, and mean aspect, were selected to test the influencing factors for the elasticity of actual evapotranspiration. Results indicate that POK is the most influencing factor for the elasticity of actual evapotranspiration in this region. Moreover, the actual evapotranspiration in karst catchments is more sensitive to precipitation change and less sensitive to the potential evapotranspiration change than that in the non-karst catchments. On the other hand, the contribution of climate change to actual evapotranspiration was generally negative in this region. Furthermore, relatively large negative contributions mainly occurred in the karst-dominated catchments, suggesting that the karst catchments were exposed to higher degradation stress brought by the climate change than that in non-karst catchments.

  1. Hydrochemistry and coal mining activity induced karst water quality degradation in the Niangziguan karst water system, China.

    PubMed

    Zhang, Xiaobo; Li, Xue; Gao, Xubo

    2016-04-01

    Hydrogeochemical analysis, statistical analysis, and geochemical modeling were employed to evaluate the impacts of coal mining activities on karst water chemistry in Niangziguan spring catchment, one of the largest karst springs in Northern China. Significant water quality deterioration was observed along the flow path, evidenced from the increasing sulfate, nitrate, and TDS content in karst water. Karst water samples are Ca-Mg-HCO3 type in the recharge areas, Ca-Mg-HCO3-SO4 type in the coal mining areas, and Ca-Mg-SO4-HCO3/HCO3-SO4 type in the rural areas and discharge areas. A four-factor principal component analysis (PCA) model is conducted which explains over 82.9% of the total variation. Factor 1, which explained the largest portion (45.33%) of the total variance, reveals that coal mining activities and natural water-rock interaction as the primary factors controlling karst water quality. Anthropogenic effects were recognized as the secondary factor with high positive loadings for NO3 (-) and Cl(-) in the model. The other two factors are co-precipitation removal of trace elements and silicate mineral dissolution, which explained 20.96% of the total variance. A two-end mixing modeling was proposed to estimate the percentage of coal wastewater giving on karst water chemistry, based on the groundwater sulfate chemistry constrains rather than sulfur isotopes. Uncertainty of sulfur isotope sources led to an overestimation of coal mining water contribution. According to the results of the modeling, the contribution of coal mining waste on karst water chemistry was quantified to be from 27.05 to 1.11% which is ca. three times lower than the values suggested using a sulfur isotope method. PMID:26614450

  2. Hydrochemistry and coal mining activity induced karst water quality degradation in the Niangziguan karst water system, China.

    PubMed

    Zhang, Xiaobo; Li, Xue; Gao, Xubo

    2016-04-01

    Hydrogeochemical analysis, statistical analysis, and geochemical modeling were employed to evaluate the impacts of coal mining activities on karst water chemistry in Niangziguan spring catchment, one of the largest karst springs in Northern China. Significant water quality deterioration was observed along the flow path, evidenced from the increasing sulfate, nitrate, and TDS content in karst water. Karst water samples are Ca-Mg-HCO3 type in the recharge areas, Ca-Mg-HCO3-SO4 type in the coal mining areas, and Ca-Mg-SO4-HCO3/HCO3-SO4 type in the rural areas and discharge areas. A four-factor principal component analysis (PCA) model is conducted which explains over 82.9% of the total variation. Factor 1, which explained the largest portion (45.33%) of the total variance, reveals that coal mining activities and natural water-rock interaction as the primary factors controlling karst water quality. Anthropogenic effects were recognized as the secondary factor with high positive loadings for NO3 (-) and Cl(-) in the model. The other two factors are co-precipitation removal of trace elements and silicate mineral dissolution, which explained 20.96% of the total variance. A two-end mixing modeling was proposed to estimate the percentage of coal wastewater giving on karst water chemistry, based on the groundwater sulfate chemistry constrains rather than sulfur isotopes. Uncertainty of sulfur isotope sources led to an overestimation of coal mining water contribution. According to the results of the modeling, the contribution of coal mining waste on karst water chemistry was quantified to be from 27.05 to 1.11% which is ca. three times lower than the values suggested using a sulfur isotope method.

  3. The karst contagion model: Synopsis and environmental implications

    NASA Astrophysics Data System (ADS)

    Kemmerly, Phillip R.

    1989-03-01

    The contagion model of karst terrane evolution focuses on the environmental implications for a large karst depression population on the Pennyroyal Plain (southern Kentucky) and the adjacent Western Highland Rim (Tennessee) immediately south of the Mammoth Cave Plateau. In karst terranes where the contagion model applies, there is a well-defined infrastructure comprised of hydrologic, structural geologic and geomorphic interacting elements that result in clustered depressions underlain by a radial conduit system. Clusters tend to be randomly distributed and typically contain a parent depression surrounded by numerous daughters. Groundwater flow is assumed to be turbulent and confined largely to conduits that are 3-dimensionally configured between clusters in a dendritic to trellis network. Parent depressions serve as conduit nodes for collecting groundwater migrating from beneath daughter depressions. Flow velocities in the 3-dimensional “cluster-cell” conduits exceed those in granular media by several orders of magnitude making pathogen and chemical contaminant migration rapid. Groundwater quality assessment in karst conduit hydrogeologic settings is difficult because monitoring wells are inappropriate. Monitoring wells may have a low probability of intercepting a major conduit and therefore the sampling regime must take into consideration the pulse discharge of pollutants in karst conduits. Representative water quality data must come from springs located near the local base level.

  4. Karst in evaporite rocks of the United States

    USGS Publications Warehouse

    Johnson, Kenneth S.

    2002-01-01

    Evaporites are the most soluble of common rocks; they are dissolved readily to form the same range of karst features that typically are found in limestones and dolomites. Evaporites, including gypsum (or anhydrite) and salt, are present in 32 of the 48 contiguous United States, and they underlie about 35-40% of the land area. Evaporite outcrops typically contain sinkholes, caves, disappearing streams, and springs. Other evidence of active karst in evaporites includes surface-collapse features and saline springs or saline plumes that result from dissolution of salt. Many evaporites, including some in the deeper subsurface, also contain evidence of paleokarst that is no longer active; this evidence includes dissolution breccias, breccia pipes, slumped beds, and collapse structures. Evaporites occur in 24 separate structural basins or geographic districts in the United States, and either local or extensive evaporite karst is known in almost all of these basins or districts. Human activities also have caused development of evaporite karst, primarily in salt deposits. Boreholes or underground mines may enable (either intentionally or inadvertently) unsaturated water to flow through or against salt deposits, thus allowing development of small to large dissolution cavities. If the dissolution cavity is large enough and shallow enough, successive roof failures can cause land subsidence or catastrophic collapse. Evaporite karst, both natural and human-induced, is far more prevalent than commonly believed.

  5. Phosphorus retention and remobilization along hydrological pathways in karst terrain.

    PubMed

    Jarvie, Helen P; Sharpley, Andrew N; Brahana, Van; Simmons, Tarra; Price, April; Neal, Colin; Lawlor, Alan J; Sleep, Darren; Thacker, Sarah; Haggard, Brian E

    2014-05-01

    Karst landscapes are often perceived as highly vulnerable to agricultural phosphorus (P) loss, via solution-enlarged conduits that bypass P retention processes. Although attenuation of P concentrations has been widely reported within karst drainage, the extent to which this results from hydrological dilution, rather than P retention, is poorly understood. This is of strategic importance for understanding the resilience of karst landscapes to P inputs, given increasing pressures for intensified agricultural production. Here hydrochemical tracers were used to account for dilution of P, and to quantify net P retention, along transport pathways between agricultural fields and emergent springs, for the karst of the Ozark Plateau, midcontinent USA. Up to ∼ 70% of the annual total P flux and ∼ 90% of the annual soluble reactive P flux was retained, with preferential retention of the most bioavailable (soluble reactive) P fractions. Our results suggest that, in some cases, karst drainage may provide a greater P sink than previously considered. However, the subsequent remobilization and release of the retained P may become a long-term source of slowly released "legacy" P to surface waters.

  6. Modeling a network of turloughs in lowland karst

    NASA Astrophysics Data System (ADS)

    Gill, L. W.; Naughton, O.; Johnston, P. M.

    2013-06-01

    In lowland karst areas of Ireland topographic depressions which get intermittently flooded on an annual cycle via groundwater sources are termed turloughs. These are sites of high ecological interest as they have communities and substrate characteristic of wetlands. The flooding in many turlough basins is due to insufficient capacity of the underground karst system to take increased flows following excessive precipitation events, causing the conduit-type network to surcharge. Continuous water level measurements have been taken in five linked turloughs in the lowland karst area of south Galway over a 3 year period. These water level fluctuations, in conjunction with river inputs and precipitation, were then used to elucidate the hydrogeological controls forming the hydraulic system beneath the ground. A model of the karst network has been developed using a pipe network model with the turloughs represented as ponds. The contribution to the karst network from diffuse flow through the epikarst via the matrix and fracture flow has also been modeled using a combination of an infiltration module and network of permeable pipes. The final model was calibrated against two separate hydrological years and in general provided a good simulation for all of the turloughs water levels particularly for the year with one main filling event. The model also accurately picked up the tidal response observed in these turloughs at shallow depths. The model has been used to predict the groundwater discharge to the coast via the main spring which had not heretofore been possible to measure, being below the sea level.

  7. Morphology, genesis and distribution of subsidence features in Dinaric karst in Slovenia

    NASA Astrophysics Data System (ADS)

    Mihevc, Andrej

    2016-04-01

    Dinaric karst is built mostly of Mesozoic limestones and dolomites. Because of large uninterrupted areas of karst, long geomorphic evolution and pure karst rocks there is not much sediment cover over karst. In spite of that the appearing of subsidence are very common. They are connected to parts of karst with specific geomorphic evolution, mostly contact karst and karst poljes where thick clastic sediments are deposited. Contact karst is the karst that developed under the impact of allogenic streams. As the contact of surface and underground flow is sensitive in some past climatic conditions these areas were often zones of sedimentation. At present washing of sediments into karst prevails sedimentation causing subsidence in ponor zones of blind valleys or border depressions very frequent. Karst poljes are the areas of karst where karst water table is close to the surface. This means low vertical gradient in karst and sedimentation or good sediment preservation. However, because of regular seasonal oscillations of water level, part of the year these sediments are in conditions where piping and subsidence can occur. In both areas collapses occur after the floods or after drop of the level of karst water below surface, mostly close to ponors or estavelles. On other geomorphic settings where collapses occur like relict poljes, dry valleys or on levelled surfaces they occur after heavy rains, often connected with thawing of snow. Collapse features are mostly cylindrical or steep-sided, usually a few metres to tens of metres in diameter. With time they transform to shallow depressions or funnel like dolines. From the point of view of geohazard the main zones of subsidence are well known and respected by locals. Even land use in endangered zones is usual less intensive and the damage caused by them is relatively small. However with loosing traditional knowledge, disobeying recommendations and growth of settlements and infrastructure the likelihood of damage increases.

  8. Sinkhole structure imaging in covered Karst terrain

    NASA Astrophysics Data System (ADS)

    Kruse, S.; Grasmueck, M.; Weiss, M.; Viggiano, D.

    2006-08-01

    Ground penetrating radar (GPR) and resistivity techniques have been widely used to map the locations of sinkholes in covered karst terrain. To determine whether a sinkhole is a likely preferential conduit for groundwater flow, however, requires higher-resolution imaging than that used in conventional sinkhole mapping surveys. Field observations combined with simulated surveys for a 15-m diameter 3-m deep sinkhole in west-central Florida are used to assess the resolution of GPR and resistivity surveys targeting the semiconfining unit that floors the sinkhole depression. 2D resistivity surveys clearly show the central depression as well as resistivity contrasts between the cover sediments within and outside of the sinkhole, but are inadequate for resolving breaches in the semiconfining unit or underlying conduits. A 3D GPR survey resolves vertical structure on the order of tens of centimeters within the semiconfining unit, as well as indicators of conduits that extend several meters beneath the central depression. 3D GPR thus holds promise for imaging hydrologically significant features of sinkholes.

  9. Hydrogeology of the karst of Puerto Rico

    USGS Publications Warehouse

    Giusti, Ennio V.

    1978-01-01

    About one-fifth of Puerto Rico is covered by a tropical karst formed on a series of six limestone formations ranging in age from middle-Oligocene to middle Miocene. These formations strike east to west and crop out over the north coast of the island. Structurally, the rocks form a simple wedge abutting southward against a mountain chain of volcanic origin and thickening northward to about 1,400 meters by the seashore. All stages of karstification are present: from the incipient, found at the western end of the belt to the residual, found at the eastern end. Maximum development of sinkholes occurs on the Aguada Limestone and upper part of the Aymanom Limestone. These formations have a CaCO3 content range from about 85 to 95 percent. The denudation rate of the Limestone belt through solution is computed as 0.70 mm per year with some evidence that abrasion may increase the denudation rate locally by as much as 40 percent. (Woodard-USGS)

  10. Thermographic Data Analyses for Karst Watersheds

    NASA Technical Reports Server (NTRS)

    Campbell, C. Warren; McCaleb, Rebecca C. (Technical Monitor)

    2001-01-01

    Aerial thermography is an emerging technology unsurpassed for locating groundwater discharges. Thermography can be used to locate submerged discharges that are extremely difficult to find by other means. In two large projects, thermography was used to identify almost every significant spring at sites underlain by karst aquifers. This technology effectively converts Brown's Type 5 topology to types 1 or 2 (all discharges known), which has a significant impact on dye tracing. At a north Alabama site, springs located by thermography quadrupled the known groundwater discharge in and around the site. For submerged discharges, thermographic temperatures can be measured down the center of the groundwater plume that rises to the surface in the winter. Using the Cornell Mixing (CORMIX) model, flow rate for one submerged spring was estimated. Once identified, estimates of spring recharge area were desired. The size of the area of recharge was estimated by hydrograph separation of flow data from nearby, unregulated surface streams. Monthly recharge estimates were also made and used to show that in north Alabama the mean annual recharge/discharge occurs during May and December. Spring flow measurements for the same county of north Alabama were averaged to obtain mean flows. Then measurements for May only, were averaged. The two averages usually agreed to within 20 percent. This provides evidence that hydrograph separation determinations of recharge are valid.

  11. Radon transport and entry in hilly karst terrains

    SciTech Connect

    Gammage, R.B.; Dudney, C.S.; Wilson, D.L.

    1991-08-01

    This report consists of copies of the view graphs used for the talk Radon Transport and Entry in Hilly Karst Terrains,'' presented at the DOE-OHER Radon Contractors' Meeting held in Albuquerque in August, 1991. The report describes how aerostatic effects can alter indoor radon concentrations, using houses in Oak Ridge and Huntsville as examples. Due to differing terrain topologies, houses in Huntsville have peak radon concentrations in the summer, roughly twice as high as winter values; Oak Ridge houses have peak radon concentrations in the winter, up to 50 times higher than summer values. A critical parameter for subsurface aerostatic transport of radon is the temperature differential between outside air and air in the underground solution cavities. The transport mechanism identified here should operate in other hilly region with karst or fractured/porous bedrock; some of the 100,000 hottest'' houses in the US are in karst regions. 3 figs., 1 tab. (MHB)

  12. A GPGPU accelerated modeling environment for quantitatively characterizing karst systems

    NASA Astrophysics Data System (ADS)

    Myre, J. M.; Covington, M. D.; Luhmann, A. J.; Saar, M. O.

    2011-12-01

    The ability to derive quantitative information on the geometry of karst aquifer systems is highly desirable. Knowing the geometric makeup of a karst aquifer system enables quantitative characterization of the systems response to hydraulic events. However, the relationship between flow path geometry and karst aquifer response is not well understood. One method to improve this understanding is the use of high speed modeling environments. High speed modeling environments offer great potential in this regard as they allow researchers to improve their understanding of the modeled karst aquifer through fast quantitative characterization. To that end, we have implemented a finite difference model using General Purpose Graphics Processing Units (GPGPUs). GPGPUs are special purpose accelerators which are capable of high speed and highly parallel computation. The GPGPU architecture is a grid like structure, making it is a natural fit for structured systems like finite difference models. To characterize the highly complex nature of karst aquifer systems our modeling environment is designed to use an inverse method to conduct the parameter tuning. Using an inverse method reduces the total amount of parameter space needed to produce a set of parameters describing a system of good fit. Systems of good fit are determined with a comparison to reference storm responses. To obtain reference storm responses we have collected data from a series of data-loggers measuring water depth, temperature, and conductivity at locations along a cave stream with a known geometry in southeastern Minnesota. By comparing the modeled response to those of the reference responses the model parameters can be tuned to quantitatively characterize geometry, and thus, the response of the karst system.

  13. The role of the subcutaneous zone in karst hydrology

    NASA Astrophysics Data System (ADS)

    Williams, Paul W.

    1983-02-01

    The subcutaneous zone is the upper weathered layer of rock beneath the soil, but above the permanently saturated (phreatic) zone. It is of particular hydrological importance in karst because of its high secondary permeability, arising from the considerable chemical solution in this zone. However, corrosional enlargement of fissures diminishes with depth; thus permeability decreases in the same direction with the result that percolation is inhibited, except down widened master joints and faults. Storage of water consequently occurs in this zone, particularly after storms. The upper surface of this suspended saturated layer in the subcutaneous zone is defined by a perched water table, which slopes towards points of rapid vertical percolation. The potential induces lateral water movement converging on the most permeable areas such as beneath dolines. Leakage from the subcutaneous store sustains slow percolation in the vadose zone. Cross-correlation of rainfall with percolation rates in caves in New Mexico, U.S.A., and New Zealand reveal response lags of 2-14 weeks with no apparent relationship to depth below the surface. Other percolation sites show no correlation with rainfall; interpreted as being a consequence of considerable friction in tight fissure networks. The recognition of storage and rapid as well as very slow percolation from the subcutaneous zone requires re-interpretation of the components of hydrographs from karst springs and of some conceptual models of karst aquifers. The importance of subcutaneous storage in sustaining baseflow discharge at some sites must be recognised, as must the contribution of subcutaneous water to flood hydrographs. Methods of estimating the volumes of subcutaneous and phreatic components of karst-spring flood hydrographs are presented. The paper concludes with a discussion of the significance of subcutaneous hydrologic processes for an understanding of karst geomorphology. The desirability of explaining karst landform

  14. Limestone types used from the classic Karst region in Slovenia

    NASA Astrophysics Data System (ADS)

    Kramar, Sabina; Mirtič, Breda; Mladenović, Ana; Rožič, Boštjan; Bedjanič, Mojca; Kortnik, Jože; Šmuc, Andrej

    2014-05-01

    The paper presents a variety of limestones from the Karst Region that is one of the most interesting areas containing reserves of natural stones in Slovenia. The region is mainly composed of Cretaceous shallow-water limestone, with the most common type currently excavated being the rudist limestone of the Lipica Formation, which dates to the Santonian to Campanian. Limestones of this formation are mainly represented by a light grey, thick-bedded to massive Lipica limestone rich in (largely fragmented) rudists. Rudist shells can be either relatively well preserved (such as in Lipica Fiorito quarried limestone) or almost completely disintegrated and intensively endolitised (Lipica Unito quarried limestone). Beside the Lipica Formation, natural stone types have been excavated from two other formations or members in the Karst region: the Repen Formation (Repen and Kopriva limestones), and the Tomaj Limestone (dark, laminated limestone within the Lipica Formation). As documented, the region has been associated with the quarrying and processing of stone at least for over two thousand years, i.e. since the Roman period. Although a large number of quarries in all mentioned formations are documented in the Karst region, many are inactive nowadays. Some of the quarries are declared as geological monuments of national importance or officially protected as a natural monument. Karst limestones are considered the highest quality calcareous natural stones in Slovenia. They are characterised by high density, low water absorption and low open porosity; consequently they also exhibit high frost and salt resistance as well as high compressive and flexural strength. Besides in the Karst region and other parts of Slovenia, the Karst limestones were used in the construction of several important buildings and monuments in many other European Countries, and worldwide. Nowadays, they are most commonly used in the construction of façade cladding, pavements, window sills, staircases, indoor

  15. Comprehensive geophysical prediction and treatment measures of karst caves in deep buried tunnel

    NASA Astrophysics Data System (ADS)

    Li, S. C.; Zhou, Z. Q.; Ye, Z. H.; Li, L. P.; Zhang, Q. Q.; Xu, Z. H.

    2015-05-01

    While tunneling in karst terrains, engineers may encounter hazardous geotechnical structures such as faults, karst caves and collapse columns which may induce geohazards and seriously endanger the construction safety. Geological processes significantly affect the varieties and characteristics of karst caves, and therefore engineering geological and hydrogeological conditions of Shangjiawan Tunnel were analyzed firstly. In order to accurately predict the geometric characteristics of karst caves and their spatial relationship with the tunnel, the Ground Penetrating Radar (GPR) and Geological Drilling (Geo-D) were applied comprehensively in the present study. The Tunnel Seismic Prediction (TSP) system was also applied to forecast whether any karst cave existed in front of the tunnel face and the detection results generally agree well with the field investigation. Furthermore, the Beam-Slab method was carried out for the treatment of the karst cave which situated under the tunnel floor, while the Backfill method was applied for the karst cave which was exposed during the construction.

  16. The characteristic trends of karst springs discharges in relation to climate change (examples from the Classical Karst, SE Slovenia)

    NASA Astrophysics Data System (ADS)

    Ravbar, Natasa; Kovacic, Gregor

    2016-04-01

    Changes in the large-scale hydrological cycle induced by global warming are among the biggest actual concerns. The observed records and climate simulations are consistent in projecting changing precipitation and temperature patterns worldwide. Particularly the incidence of changed precipitation amount, intensity and variability may increase changes in hydrological regimes, and could have implications on water quantity and quality in many areas. This may affect freshwater dependant ecosystems and several socio-economic activities. Groundwater resources availability, stability of access and utilisation may further provoke difficulties for many services, such as drinking water supply, agriculture, industry, hydropower, etc. Karst aquifers are due to their specific nature (i.e. rapid infiltration rates and underground water flow, highly controlled by conduits) highly dependent on respective hydrological conditions. The goal of this study was to better understand how and to what extent impacts of the climate change may affect karst groundwater resources and to quantify the role of karst aquifers in flood attenuation and baseflow maintenance. The characteristic linear trends of mean, minimal and maximal annual discharge values of nine selected karst springs in SE Slovenia have been assessed and compared with the linear trends of annual precipitation amount and air temperature covering a 52-year period (1961 - 2013). The data have also been evaluated in respect to the individual spring's catchment characteristics (e.g. storage capacity). Obtained results and analysis reveal the impacts of climate (environmental) change on karst groundwater and call for urgent adherence of standards for karst water sources protection, monitoring and rational use in the relevant management strategies.

  17. Karstification, Caves and Karst Aquifers on the Adriatic Islands (Croatia)

    NASA Astrophysics Data System (ADS)

    Garasic, M.; Terzic, J.

    2009-04-01

    This article deals with the Adriatic karst island aquifers especially from the point of view of karstification and how karst phenomena influence the accumulation of groundwater, its movements inside the system and its outflow. Flow through karst channels has been separated from flow through fractures within the rock mass regarding the scale of study. Although it is usually understood that groundwater flow in karst aquifers is usually turbulent, it has been shown that this phenomenon should also be taken into consideration regarding the scale. Turbulent flows are present in karst channels, but on most islands the majority of flow is happening through the network of fractures and joints within the rock mass, and that flow is predominantly laminar proven by statistic processing of step-drawdown pumping test. It has been shown how extensive and systematical research of karst aquifers must cover both phenomena. The most significant method of karst channel flows research as well as for disintegrated fault zones tracing is pointed out. On the other hand, while rock mass behaves according to the Darcy's law to a certain extent, hydraulic parameters can be used for description of such an aquifer. Still, in karst terrains all hydraulic values should be taken only as approximations. Based on all known findings it is possible to conclude that karstification processes are very important for hydrogeologic research on the Adriatic islands. In order to understand those processes, besides the karstification process, it is also important to know about the changes in sea level during recent geologic past - especially in Holocene. Karst phenomena from earlier karstification phases also exist and participate in the whole hydrogeologic setting, but because of the latter processes, they don't have the significance of recent ones which are still hydrogeologically active. Due to karstification and the presence of dissolution cavities, channels, and speleological objects, a very

  18. Microbial Source Tracking in Adjacent Karst Springs

    PubMed Central

    Vaizel-Ohayon, Dalit; Rom, Meir; Guttman, Joseph; Berger, Diego; Kravitz, Valeria; Pilo, Shlomo; Huberman, Zohar; Kashi, Yechezkel; Rorman, Efrat

    2015-01-01

    Modern man-made environments, including urban, agricultural, and industrial environments, have complex ecological interactions among themselves and with the natural surroundings. Microbial source tracking (MST) offers advanced tools to resolve the host source of fecal contamination beyond indicator monitoring. This study was intended to assess karst spring susceptibilities to different fecal sources using MST quantitative PCR (qPCR) assays targeting human, bovine, and swine markers. It involved a dual-time monitoring frame: (i) monthly throughout the calendar year and (ii) daily during a rainfall event. Data integration was taken from both monthly and daily MST profile monitoring and improved identification of spring susceptibility to host fecal contamination; three springs located in close geographic proximity revealed different MST profiles. The Giach spring showed moderate fluctuations of MST marker quantities amid wet and dry samplings, while the Zuf spring had the highest rise of the GenBac3 marker during the wet event, which was mirrored in other markers as well. The revelation of human fecal contamination during the dry season not connected to incidents of raining leachates suggests a continuous and direct exposure to septic systems. Pigpens were identified in the watersheds of Zuf, Shefa, and Giach springs and on the border of the Gaaton spring watershed. Their impact was correlated with partial detection of the Pig-2-Bac marker in Gaaton spring, which was lower than detection levels in all three of the other springs. Ruminant and swine markers were detected intermittently, and their contamination potential during the wet samplings was exposed. These results emphasized the importance of sampling design to utilize the MST approach to delineate subtleties of fecal contamination in the environment. PMID:26002893

  19. Microbial Source Tracking in Adjacent Karst Springs.

    PubMed

    Ohad, Shoshanit; Vaizel-Ohayon, Dalit; Rom, Meir; Guttman, Joseph; Berger, Diego; Kravitz, Valeria; Pilo, Shlomo; Huberman, Zohar; Kashi, Yechezkel; Rorman, Efrat

    2015-08-01

    Modern man-made environments, including urban, agricultural, and industrial environments, have complex ecological interactions among themselves and with the natural surroundings. Microbial source tracking (MST) offers advanced tools to resolve the host source of fecal contamination beyond indicator monitoring. This study was intended to assess karst spring susceptibilities to different fecal sources using MST quantitative PCR (qPCR) assays targeting human, bovine, and swine markers. It involved a dual-time monitoring frame: (i) monthly throughout the calendar year and (ii) daily during a rainfall event. Data integration was taken from both monthly and daily MST profile monitoring and improved identification of spring susceptibility to host fecal contamination; three springs located in close geographic proximity revealed different MST profiles. The Giach spring showed moderate fluctuations of MST marker quantities amid wet and dry samplings, while the Zuf spring had the highest rise of the GenBac3 marker during the wet event, which was mirrored in other markers as well. The revelation of human fecal contamination during the dry season not connected to incidents of raining leachates suggests a continuous and direct exposure to septic systems. Pigpens were identified in the watersheds of Zuf, Shefa, and Giach springs and on the border of the Gaaton spring watershed. Their impact was correlated with partial detection of the Pig-2-Bac marker in Gaaton spring, which was lower than detection levels in all three of the other springs. Ruminant and swine markers were detected intermittently, and their contamination potential during the wet samplings was exposed. These results emphasized the importance of sampling design to utilize the MST approach to delineate subtleties of fecal contamination in the environment.

  20. Supai salt karst features: Holbrook Basin, Arizona

    SciTech Connect

    Neal, J.T.

    1994-12-31

    More than 300 sinkholes, fissures, depressions, and other collapse features occur along a 70 km (45 mi) dissolution front of the Permian Supai Formation, dipping northward into the Holbrook Basin, also called the Supai Salt Basin. The dissolution front is essentially coincident with the so-called Holbrook Anticline showing local dip reversal; rather than being of tectonic origin, this feature is likely a subsidence-induced monoclinal flexure caused by the northward migrating dissolution front. Three major areas are identified with distinctive attributes: (1) The Sinks, 10 km WNW of Snowflake, containing some 200 sinkholes up to 200 m diameter and 50 m depth, and joint controlled fissures and fissure-sinks; (2) Dry Lake Valley and contiguous areas containing large collapse fissures and sinkholes in jointed Coconino sandstone, some of which drained more than 50 acre-feet ({approximately}6 {times} 10{sup 4} m{sup 3}) of water overnight; and (3) the McCauley Sinks, a localized group of about 40 sinkholes 15 km SE of Winslow along Chevelon Creek, some showing essentially rectangular jointing in the surficial Coconino Formation. Similar salt karst features also occur between these three major areas. The range of features in Supai salt are distinctive, yet similar to those in other evaporate basins. The wide variety of dissolution/collapse features range in development from incipient surface expression to mature and old age. The features began forming at least by Pliocene time and continue to the present, with recent changes reportedly observed and verified on airphotos with 20 year repetition. The evaporate sequence along interstate transportation routes creates a strategic location for underground LPG storage in leached caverns. The existing 11 cavern field at Adamana is safely located about 25 miles away from the dissolution front, but further expansion initiatives will require thorough engineering evaluation.

  1. Karst is a repository for old sediments

    SciTech Connect

    Hobbs, H.C. )

    1994-04-01

    The Paleozoic plateau of southeastern Minnesota has been repeatedly glaciated, and has accumulated several sheets of loess. In the eastern part of this area, most of the older sediments have been eroded away and the late Wisconsinan Peoria loess directly overlies limestone. A lag of erratics from one or more older tills occurs sporadically on the bedrock surface. A more complete record is preserved in some sinkholes and solution cavities. Sinkholes (surface depressions) contain material that washed or collapsed into the hole, as well as material that was deposited directly (such as loess). Solution cavities contain only material sorted by water. Sinkhole fills exposed in roadcuts and quarry walls commonly lack the surface expression and black-dirt funnel'' of active sinkholes. Several of these contain erratic-bearing sediment interpreted as slopewash and mudflow. One appears to contain actual till--unsorted, unbedded pebble-loam that is not mixed with other materials commonly found on the limestone surface, such as red clay or loess. It cannot be determined whether this material was deposited directly or collapsed in later. Solution cavities are typically packed with sediment right up to the top. The bulk of such deposits is typically clay and silt; however, erratic pebbles are present in some. The fine sediment is sorted and bedded, at least in places. In one large cavity fill, a layer of rip-up clay clasts occurs near the top. Study of the stratigraphy of karst sediments in southeastern Minnesota is still preliminary. Techniques which are used to correlate them include: physical characteristics, texture analysis (on material that has not been sorted), sand and pebble lithology, and magnetic polarity. Techniques that could be used include clay mineralogy, geochemical analysis, and thermoluminescence.

  2. Carbon uptake by karsts in the Houzhai Basin, southwest China

    NASA Astrophysics Data System (ADS)

    Yan, Junhua; Wang, Y. P.; Zhou, Guoyi; Li, Shenggong; Yu, Guirui; Li, Kun

    2011-12-01

    Using an estimated bicarbonate concentration ([HCO3-]) in water and discharge rates of surface water and underground water from the Houzhai Basin, southwest China, from 1986 to 2007, we estimate that the mean carbon uptake rate was 20.7 g C m-2 yr-1. The surface water and underground water contribute about equally to the total carbon uptake from 1986 to 2007. About 97% of the interannual variation of annual carbon uptake can be explained by the discharge rate. Within a year, the net carbon uptake rate by karst during the wet season (May-October) was found to be about 2.4 times that during the dry season (November-April). If the seasonal variations of discharge rate and bicarbonate concentrations are not accounted for, estimates of annual net carbon uptake by karst can be biased by >25%, but that bias becomes very small (<5%) when averaged from 1986 to 2007 for the Houzhai Basin. We also found that one of the empirical models as used in global modeling overestimated the net carbon uptake by karst at Houzhai Basin by 29%. Carbon uptake from chemical weathering of all karsts in China is estimated to be about 12 Tg C yr-1 at present (1 Tg = 1012 g), or about 57% of the rate of net carbon accumulated in the forest biomass from 1981 to 1998 in China; we therefore recommend the inclusion of carbon uptake from chemical weathering in the regional carbon budget of China.

  3. Model validation for karst flow using sandbox experiments

    NASA Astrophysics Data System (ADS)

    Ye, M.; Pacheco Castro, R. B.; Tao, X.; Zhao, J.

    2015-12-01

    The study of flow in karst is complex due of the high heterogeneity of the porous media. Several approaches have been proposed in the literature to study overcome the natural complexity of karst. Some of those methods are the single continuum, double continuum and the discrete network of conduits coupled with the single continuum. Several mathematical and computing models are available in the literature for each approach. In this study one computer model has been selected for each category to validate its usefulness to model flow in karst using a sandbox experiment. The models chosen are: Modflow 2005, Modflow CFPV1 and Modflow CFPV2. A sandbox experiment was implemented in such way that all the parameters required for each model can be measured. The sandbox experiment was repeated several times under different conditions. The model validation will be carried out by comparing the results of the model simulation and the real data. This model validation will allows ud to compare the accuracy of each model and the applicability in Karst. Also we will be able to evaluate if the results of the complex models improve a lot compared to the simple models specially because some models require complex parameters that are difficult to measure in the real world.

  4. Evaluating Transmissivity Estimates from Well Hydrographs in Karst Aquifers

    SciTech Connect

    Powers, J.g.; Shevenell, l

    1999-07-01

    Hydrograph recessions from rainfall events have previously been analyzed for discharge at springs and streams; however, relatively little quantitative research has been conducted with regard to hydrograph analysis of recessions from monitoring wells screened in karst aquifers. In previous work a quantitative hydrography analysis technique has been proposed born which matrix transmissivity (i.e., transmissivity of intergranular porosity) and specific yields of matrix, fracture, and conduit components of the aquifer may be determined from well hydrography. The technique has yielded realistic results at three sites tested by the authors thus far (Y-12, Oak Ridge, TN; Crane, IN, and Ft. Campbell, KY). Observed field data, as well as theoretical considerations, show that karst well hydrography are valid indicators of hydraulic properties of the associated karst aquifers. Results show matrix transmissivity (T) values to be in good agreement with values calculated using more traditional parameter estimation techniques such as aquifer pumping tests and slug tests in matrix dominated wells. While the hydrograph analysis technique shows promise for obtaining reliable estimates of karst aquifer T with a simple, relatively inexpensive and passive method, the utility of the technique is limited in its application depending on site-specific hydrologic conditions, which include shallow, submerged conduit systems located in areas with sufficient rainfall for water levels to respond to precipitation events.

  5. Environmental and engineering problems of karst geology in China

    SciTech Connect

    Yuan Daoxian )

    1988-10-01

    Karst terrane is generally regarded as a fragile and vulnerable environment. Its underground drainage system can aggravate both drought and flood problems; the lack of filtration in an underground conduit makes waste disposal more difficult; and the lack of soil cover in bare karstland can enhance deforestation. Moreover, karst terranes are quite often haunted by a series of engineering problems, such as water gushing into mines or transportation tunnels; leakage from reservoirs; and failure of building foundations. In China, there are more than 200 cases of karst collapse, which include many thousands of individual collapse points. Some of these are paleo and natural collapses, but most of them are modern collapses induced by human activities and they have caused serious damage. Many factors such as geologic structure, overburden thickness and character, lithologic features of karstified rock, and intensity of karstification are related to development and distribution of modern collapses. However, China's karst is mainly developed in pre-Triassic, old phase, hard, compact, carbonate rock. Consequently most modern collapses have occurred only in the overlying soil. So it is understandable that the fluctuation of the water table in the underlying karstified strata plays an important role in the process of collapse. Nevertheless, there are different explanations as to how the groundwater activities can induce collapse.

  6. Simulation of Cavern Formation and Karst Development Using Salt

    ERIC Educational Resources Information Center

    Kent, Douglas C.; Ross, Alex R.

    1975-01-01

    A salt model was developed as a teaching tool to demonstrate the development of caverns and karst topography. Salt slabs are placed in a watertight box to represent fractured limestone. Erosion resulting from water flow can be photographed in time-lapse sequence or demonstrated in the laboratory. (Author/CP)

  7. FECAL BACTERIAL CONTAMINATION OF A KARST WATERSHED IN CENTRAL MISSOURI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Bonne Femme watershed of Boone County, Missouri has a varied surface geology that includes karst topography with losing streams that are an especially vulnerable setting for ground water contamination. The study objective was to compare fecal contamination and detection of specific pathogenic wa...

  8. Natural and anthropogenic hazards in the Bohol karst

    NASA Astrophysics Data System (ADS)

    Day, Mick; Urich, Peter

    2010-05-01

    About 40% of the island of Bohol is karst landscape, and karstic hazards affect much of this area, which contains about 75% of the population of 1.1 million. The inland karst consists of broad, alluviated valleys or poljes punctuated by isolated residuals (mogotes) and separated by uplands which are dissected by underdrained and abandoned dry valley systems, themselves dismembered by polygonal enclosed depressions (cockpits) and bordered by sinuous residual interfluvial ridges, which adjacent to the enclosed depressions have been reduced to isolated or connected residual hills. With population and urbanization increasing, and as infrastructure is developed, karstic hazards are becoming more prevalent and risks are increasing. One major natural hazard is seasonal drought, which disrupts water supplies, particularly in upland areas where groundwater resources are poorly developed and residents depend on rainwater and springs. Conversely, seasonal flooding, particularly that associated with tropical storms and extreme events, causes property damage and human death, injury and displacement in the valleys. Ground surface subsidence and collapse threatens developing infrastructure, dwellings and livestock, but the potential for catastrophic karstic failure appears to be limited. Slope failure also occurs, but is not often recognized as a hazard and has not been studied in detail. Human impacts include quarrying, groundwater abstraction, groundwater contamination, urbanization, agricultural development and tourism. Less than ten percent of the karst area is within protected areas and the karst is the setting for contemporary civil strife.

  9. A simulation model to assess groundwater recharge over Europe's karst regions

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Gleeson, T.; Rosolem, R.; Pianosi, F.; Wada, Y.; Wagener, T.

    2014-11-01

    Karst develops through the dissolution of carbonate rock and is a major source of groundwater contributing up to half of the total drinking water supply in some European countries. Previous approaches to model future water availability in Europe are either too-small scale or do not incorporate karst processes, i.e. preferential flow paths. This study presents the first simulations of groundwater recharge in all karst regions in Europe with a parsimonious karst hydrology model. A novel parameter confinement strategy combines a priori information with recharge-related observations (actual evapotranspiration and soil moisture) at locations across Europe while explicitly identifying uncertainty in the model parameters. Europe's karst regions are divided into 4 typical karst landscapes (humid, mountain, Mediterranean and desert) by cluster analysis and recharge is simulated from 2002 to 2012 for each karst landscape. Mean annual recharge ranges from negligible in deserts to > 1 m a-1 in humid regions. The majority of recharge rates ranges from 20-50% of precipitation and are sensitive to sub-annual climate variability. Simulation results are consistent with independent observations of mean annual recharge and significantly better than other global hydrology models that do not consider karst processes (PCR-GLOBWB, WaterGAP). Global hydrology models systematically underestimate karst recharge implying that they over-estimate actual evapotranspiration and surface runoff. Karst water budgets and thus information to support management decisions regarding drinking water supply and flood risk are significantly improved by our model.

  10. Past and present management of water resources in karst environments

    NASA Astrophysics Data System (ADS)

    Parise, Mario

    2010-05-01

    Karst is a very peculiar environment, and has a number of intrinsic features that clearly distinguish it from any other natural setting. Hydrology of karst is dominated by absence or very scarce presence of surface runoff, since water rapidly infiltrates underground through the complex network of conduits and fissures that are at the origin of the development of karst caves. The limited presence of water at the surface represented the main problem to be faced by man, starting from the very first historic phases of establishing settlements in karst territories. As often happens in areas with limited natural resources, man was however able to understand the local environment through observations and direct experience, develop technique in order to collect the limited available water resources, and adapt his way of life to the need of the natural environment. In a few words, a sustainable use of the water resources was reached, that went on for many centuries, allowing development of human settlements and agriculture, and, at the same time, protecting and safeguarding the precious hydric resources. Some of the most typical rural architectures built in karst areas of the Mediterranean Basin can be described as examples of such efforts: from the dry stone walls, to many types of storage-houses or dwellings, known with different names, depending upon the different countries and regions. Dry stone walls, in particular, deserve a particular attention, since they had multiple functions: to delimit the fields and properties, to act as a barrier to soil erosion, to allow terracing the high-gradient slopes, to collect and store water. At this latter aim, dry stone walls were build in order to create a small but remarkable micro-environment, functioning as collectors of moisture and water vapour. In the last centuries, with particular regard to the last decades of XX century, the attention paid by man to the need of the natural environment has dramatically changed. This

  11. On ground water residence time in karst aquifers

    NASA Astrophysics Data System (ADS)

    Gabrovsek, Franci; Petric, Metka; Kogovšek, Janja; Dreybrodt, Wolfgang

    2015-04-01

    Residence time of groundwater in karst aquifers span several orders of magnitude. To demonstrate some parts of this wide spectrum, several approaches are presented here. First, a genetic numerical model is used to study the spreading of plumes through confined telogenetic karst aquifer. Digital models of fractured karst aquifer at different stages of early karstification with well defined flow velocities are used as a "test sites". A particle tracking algorithm is applied to study the advective spreading of plumes caused by instantaneous input into selected region of the modelling domain. The simulations shows high variability of the resulting transfer functions, depending on the stage of evolution, the structure of initial network, the boundary conditions and the location of particle injection. Besides idealistic modelling scenario, several field studies in Dinaric karst systems in Slovenia are reviewed with focus to the ground water residence time. The methods include dye tracing experiments and continuous monitoring of ground water in epiphreatic caves. The studied systems have evolved in complex tectonic settings and are characterised by the network of epiphreatic conduits, interrupted by large collapse chambers and dolines. Dye tracing experiments revealed surprising flow paths and high variations of residence time at different hydrological conditions. Important information on the velocity of groundwater flow in large epiphreatic conduits can be obtained from continuous and simultaneous monitoring of ground water parameters in active caves in a selected system. Such cases from Reka - Timavo system and Postojna - Planina cave system are presented, where temperature is used as a ground water tracer and the results were compared to the results of dye tracing. Vadose zone presents the biggest challenge for characterisation of groundwater flow in karst. Many different flow paths show extremely high variability in flow velocities/residence times. These is

  12. Eogenetic karst hydrology: insights from the 2004 hurricanes, peninsular Florida.

    PubMed

    Florea, Lee J; Vacher, H L

    2007-01-01

    Eogenetic karst lies geographically and temporally close to the depositional environment of limestone in warm marine water at low latitude, in areas marked by midafternoon thunderstorms during a summer rainy season. Spring hydrographs from such an environment in north-central Florida are characterized by smooth, months-long, seasonal maxima. The passage of Hurricanes Frances and Jeanne in September 2004 over three field locations shows how the eogenetic karst of the Upper Floridan Aquifer responds to unequivocal recharge events. Hydrographs at wells in the High Springs area, Rainbow Springs, and at Morris, Briar, and Bat Caves all responded promptly with a similar drawn-out rise to a maximum that extended long into the winter dry season. The timing indicates that the typical hydrograph of eogenetic karst is not the short-term fluctuations of springs in epigenic, telogenetic karst, or the smoothed response to all the summer thunderstorms, but rather the protracted response of the system to rainfall that exceeds a threshold. The similarity of cave and noncave hydrographs indicates distributed autogenic recharge and a free communication between secondary porosity and permeable matrix-both of which differ from the hydrology of epigenic, telogenetic karst. At Briar Cave, drip rates lagged behind the water table rise, suggesting that recharge was delivered by fractures, which control the cave's morphology. At High Springs, hydrographs at the Santa Fe River and a submerged conduit apparently connected to it show sharp maxima after the storms, unlike the other cave hydrographs. Our interpretation is that the caves, in general, are discontinuous. PMID:17600574

  13. [Characteristic of ammonia nitrogen adsorption on karst underground river sediments].

    PubMed

    Guo, Fang; Chen, Kun-Kun; Jiang, Guang-Hui

    2011-02-01

    Karst aquifers are one of the most important aquifers in Southwestern China. One of the characteristics of karst aquifers is the enhanced permeability permits high flow velocities are capable of transporting suspended and bedload sediments. Mobile sediment in karst may act as a vector for the transport of contaminates. 14 sediment samples were collected from two underground rivers in two typical karst areas in Liuzhou city, Guangxi Autonomous Region, China. According to simulated experiment methods, characteristic of adsorption of ammonia nitrogen on sediment was studied. The results of ammonia nitrogen adsorption dynamics on sediments showed that the maximum adsorption velocity was less than 2 h. The adsorption balance quantity in 5 h accounted for 71% - 98% of the maximum adsorption quantity. The maximum adsorption quantity of ammonia nitrogen was 385.5 mg/kg, which was sediment from a cave in the middle areas of Guancun underground river system. The study of isotherm adsorption indicated adsorption quantity of NH4+ increase followed by incremental balance concentration of NH4+ in the aquatic phase. Adsorption quantity of ammonia nitrogen in sediments has a relative linear relationship with adsorption balance concentrations. Adsorption-desorption balance concentrations were all low, indicating sediments from underground rivers have great adsorption potential. Under the condition of low and high concentrations of ammonia nitrogen in overlying water, Langmuir and Tempkin couldn't simulate or simulate results couldn't reach remarkable level, whilst Linear and Freundlich models could simulate well. Research on different type sediments, sampling times and depths from two underground rivers shows characteristic of ammonia nitrogen adsorption on karst underground river sediments doesn't have good correspondence with the type of sediments. One of the reasons is there is no big difference between sediments in the development of climate, geology, hydrological conditions

  14. Eogenetic karst hydrology: insights from the 2004 hurricanes, peninsular Florida.

    PubMed

    Florea, Lee J; Vacher, H L

    2007-01-01

    Eogenetic karst lies geographically and temporally close to the depositional environment of limestone in warm marine water at low latitude, in areas marked by midafternoon thunderstorms during a summer rainy season. Spring hydrographs from such an environment in north-central Florida are characterized by smooth, months-long, seasonal maxima. The passage of Hurricanes Frances and Jeanne in September 2004 over three field locations shows how the eogenetic karst of the Upper Floridan Aquifer responds to unequivocal recharge events. Hydrographs at wells in the High Springs area, Rainbow Springs, and at Morris, Briar, and Bat Caves all responded promptly with a similar drawn-out rise to a maximum that extended long into the winter dry season. The timing indicates that the typical hydrograph of eogenetic karst is not the short-term fluctuations of springs in epigenic, telogenetic karst, or the smoothed response to all the summer thunderstorms, but rather the protracted response of the system to rainfall that exceeds a threshold. The similarity of cave and noncave hydrographs indicates distributed autogenic recharge and a free communication between secondary porosity and permeable matrix-both of which differ from the hydrology of epigenic, telogenetic karst. At Briar Cave, drip rates lagged behind the water table rise, suggesting that recharge was delivered by fractures, which control the cave's morphology. At High Springs, hydrographs at the Santa Fe River and a submerged conduit apparently connected to it show sharp maxima after the storms, unlike the other cave hydrographs. Our interpretation is that the caves, in general, are discontinuous.

  15. Eogenetic karst hydrology: Insights from the 2004 hurricanes, peninsular Florida

    USGS Publications Warehouse

    Florea, L.J.; Vacher, H.L.

    2007-01-01

    Eogenetic karst lies geographically and temporally close to the depositional environment of limestone in warm marine water at low latitude, in areas marked by midafternoon thunderstorms during a summer rainy season. Spring hydrographs from such an environment in north-central Florida are characterized by smooth, months-long, seasonal maxima. The passage of Hurricanes Frances and Jeanne in September 2004 over three field locations shows how the eogenetic karst of the Upper Floridan Aquifer responds to unequivocal recharge events. Hydrographs at wells in the High Springs area, Rainbow Springs, and at Morris, Briar, and Bat Caves all responded promptly with a similar drawn-out rise to a maximum that extended long into the winter dry season. The timing indicates that the typical hydrograph of eogenetic karst is not the short-term fluctuations of springs in epigenic, telogenetic karst, or the smoothed response to all the summer thunderstorms, but rather the protracted response of the system to rainfall that exceeds a threshold. The similarity of cave and noncave hydrographs indicates distributed autogenic recharge and a free communication between secondary porosity and permeable matrix - both of which differ from the hydrology of epigenic, telogenetic karst. At Briar Cave, drip rates lagged behind the water table rise, suggesting that recharge was delivered by fractures, which control the cave's morphology. At High Springs, hydrographs at the Santa Fe River and a submerged conduit apparently connected to it show sharp maxima after the storms, unlike the other cave hydrographs. Our interpretation is that the caves, in general, are discontinuous. ?? 2007 National Ground Water Association.

  16. A new species of karst-adapted Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) from a threatened karst region in Pahang, Peninsular Malaysia.

    PubMed

    Grismer, L Lee; Wood, Perry L; Mohamed, Maketab; Chan, Kin Onn; Heinz, Heather M; Sumarli, Alex S-I; Chan, Jacob A; Loredo, Ariel I

    2013-12-12

    A new species of karst-adapted gekkonid lizard of the genus Cnemaspis Strauch is described from Gua Gunting and Gua Goyang in a karst region of Merapoh, Pahang, Peninsular Malaysia whose unique limestone formations are in immediate danger of being quarried. The new species differs from all other species of Cnemaspis based on its unique suite of morphological and color pattern characters. Its discovery underscores the unique biodiversity endemic to karst regions and adds to a growing list of karst-adapted reptiles from Peninsular Malaysia. We posit that new karst-adapted species endemic to limestone forests will continue to be discovered and these regions will harbor a significant percentage of Peninsular Malaysia's biodiversity and thusly should be conserved rather than quarried.

  17. Karst water resources in a changing world: Review of hydrological modeling approaches

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Goldscheider, N.; Wagener, T.; Lange, J.; Weiler, M.

    2014-09-01

    Karst regions represent 7-12% of the Earth's continental area, and about one quarter of the global population is completely or partially dependent on drinking water from karst aquifers. Climate simulations project a strong increase in temperature and a decrease of precipitation in many karst regions in the world over the next decades. Despite this potentially bleak future, few studies specifically quantify the impact of climate change on karst water resources. This review provides an introduction to karst, its evolution, and its particular hydrological processes. We explore different conceptual models of karst systems and how they can be translated into numerical models of varying complexity and therefore varying data requirements and depths of process representation. We discuss limitations of current karst models and show that at the present state, we face a challenge in terms of data availability and information content of the available data. We conclude by providing new research directions to develop and evaluate better prediction models to address the most challenging problems of karst water resources management, including opportunities for data collection and for karst model applications at so far unprecedented scales.

  18. Inventory of karst subsidence in the Valley and Ridge Province of East Tennessee

    SciTech Connect

    Ketelle, R.H.; Newton, J.G.

    1986-01-01

    The first regional inventory of karst activity in the Valley and Ridge Province of East Tennessee was performed as a part of ongoing studies at Oak Ridge National Laboratory pertaining to environmental impact assessment of waste disposal in karst settings. More than half the land area in the Valley and Ridge Province of East Tennessee is underlain by karst-prone carbonate bedrock. The regional karst inventory was initiated to obtain current information on the extent of active karst subsidence in the region for use in decision making by the Department of Energy in planning future waste disposal facilities at Oak Ridge, Tennessee. The inventory was performed by contacting personnel of federal, state, and county agencies to obtain reports of known active karst subsidence within the region. Data from these interviews were tabulated resulting in identificaton of more than 250 karst subsidence incidents in East Tennessee, most of which have occurred since 1980. Although the infomation obtained was largely anecdotal, approximate location, date, size, and circumstances under which the collapses occurred were recorded for as many cases as could be documented. The study also included detailed reconnaissance of selected areas similar in geology and hydrology to a study area at Oak Ridge, Tennessee to identify causative factors which contribute to karst subsidence in the region and for comparison of the occurrence of visible karst features at different sites. Human activities affecting site hydrology such as large scale land clearing and earthmoving projects were related to most of the subsidence incidents inventoried.

  19. GIS thematic layers for assessing karst hazard in Murgia region (Italy)

    NASA Astrophysics Data System (ADS)

    Canora, Filomena; D'Angella, Annachiara; Fidelibus, Dolores; Lella, Angela; Pellicani, Roberta; Spilotro, Giuseppe

    2013-04-01

    The assessment of karst hazard in a carbonate area may be somewhat complex for the multiplicity of involved factors (geological, hydrological, morphological, anthropogenic, etc.), their history and the slow rate of evolution of the processes. In coastal areas, moreover, the long term sea level variations and the short term oscillations generally influence the generation and evolution of the karst process. Another peculiarity of the karst hazard assessment consists in the difficulty for identifying the location of subsurface forms, which may develop over very large areas without any kind of surface signal. The karst processes and landforms often require specific methods of investigation and mitigation, due to the unique and highly variable characters of karst environments. In addition, the hidden character of the karst processes, often accelerated by human activity, is an issue with significant economic impact, affecting many regions of the world. The assessment of karst hazard in the Murgia plateau (in central-west of Apulia region) is the main goal of this research. For this aim, the typologies of karst phenomena, able to produce hazard in the study area, were individuated and collected in a specific database. The hazard was evaluated on the basis of the probability of occurrence of a phenomenon of instability, active (produced by human activities) or passive (natural evolution of karst process), in relation to the presence, evolution or generation of karst forms on surface or at critical distance from the surface. The critical distance from the surface is defined as the distance at which the local or general destructive evolution of a karst process can produce a variation of the usability of the area or of the value of elements involved in the instability. The thematic layers relative to the factors influencing karst processes and landforms (doline, sinkholes, polje, lame, gravine, caves) were elaborated and managed in a GIS system. The archives of the main karst

  20. Origin of the term ``karst,'' and the transformation of the classical karst (kras)

    NASA Astrophysics Data System (ADS)

    Gams, I.

    1993-06-01

    The limestone region northeast of Trieste Bay is named “kras” in Slovenian, “karst” in German, and “carso” in Italian, from a pre-Indo-European word “karra” meaning stony. The natural vegetation was deciduous forest. Clearance and burning to create pasture for sheep began in the first millenium BC and resulted in considerable losses of soil into underground karstic channels. By the Middle Ages, the region was known as a rocky, treeless land; the first legislation to conserve or re-establish forests was passed but it did not succeed. In the 19th century the regional name came to be adopted as the generic name for all dissolutional landscapes and hydrogeological systems, whether natural or modified. During this period a change from sheep rearing to dairying with cattle, plus new legislation and experimental plantings with black pine ( Pinus nigra), began the restoration of the forests in the Karst itself. Since 1945 their extent has more than doubled again, partly as consequences of rural depopulation and the banning of goats; approximately 50 percent of the region is now covered by woodlands. Soil erosion is much reduced, but evapotranspiration losses have probably increased. It is hypothesized that there will be effects of restoration upon such karstic parameters as the discharge of springs or rates of travertine deposition in the caves.

  1. Phylogenetic analysis on the soil bacteria distributed in karst forest

    PubMed Central

    Zhou, JunPei; Huang, Ying; Mo, MingHe

    2009-01-01

    Phylogenetic composition of bacterial community in soil of a karst forest was analyzed by culture-independent molecular approach. The bacterial 16S rRNA gene was amplified directly from soil DNA and cloned to generate a library. After screening the clone library by RFLP, 16S rRNA genes of representative clones were sequenced and the bacterial community was analyzed phylogenetically. The 16S rRNA gene inserts of 190 clones randomly selected were analyzed by RFLP and generated 126 different RFLP types. After sequencing, 126 non-chimeric sequences were obtained, generating 113 phylotypes. Phylogenetic analysis revealed that the bacteria distributed in soil of the karst forest included the members assigning into Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi (Green nonsulfur bacteria), Bacteroidetes, Verrucomicrobia, Nitrospirae, Actinobacteria (High G+C Gram-positive bacteria), Firmicutes (Low G+C Gram-positive bacteria) and candidate divisions (including the SPAM and GN08). PMID:24031430

  2. Karst in Permian evaporite rocks of western Oklahoma

    SciTech Connect

    Johnson, K.S. )

    1993-02-01

    Bedded evaporites (gypsum and salt) of Permian age have been dissolved naturally by ground water to form a major evaporite-karst region in western Oklahoma. The Blaine Formation and associated evaporites comprise 100--800 ft of strata that dip gently into broad, structural basins. Outcropping gypsum, dolomite, and red-bed shales of the Blaine display typical karstic features, such as sinkholes, caves, disappearing streams, and springs. Large caves are developed in gypsum beds 10--30 ft thick at several places, and a major gypsum/dolomite karst aquifer provides irrigation water to a large region in southwestern Oklahoma, where salt layers above and below the Blaine Formation have been partly dissolved at depths of 30--800 ft below the land surface. Salt dissolution causes development of brine-filled cavities, into which overlying strata collapse, and the brine eventually is emitted at the land surface in large salt plains.

  3. PaPRIKa: a method for estimating karst resource and source vulnerability—application to the Ouysse karst system (southwest France)

    NASA Astrophysics Data System (ADS)

    Kavouri, Konstantina; Plagnes, Valérie; Tremoulet, Joël; Dörfliger, Nathalie; Rejiba, Fayçal; Marchet, Pierre

    2011-03-01

    The intrinsic vulnerability mapping method, PaPRIKa, is proposed as a common basis for karst groundwater protection in France. PaPRIKa is a specialized method for studying karst aquifers, derived from updating the RISKE and EPIK methods. Both the structure and functioning of karst aquifers are considered in order to develop a resource and source-vulnerability mapping method. PaPRIKa means Protection of aquifers from the assessment of four criteria: P for protection (considering the most protective aspects among parameters related to soil cover, unsaturated zone and epikarst behavior), R for rock type, I for infiltration and Ka for karstification degree. The Ouysse karst system, located in the Causses area in southwest France, is one of the nine pilot sites where this method was tested and standardized. The specificities of the Ouysse system such as the size of the catchment area, the spatial variability of the karst network development, the thick infiltration zone and the system's dual character (both karst and non-karst areas), have provided a valuable field of application. The vulnerability of the resource was assessed for the entire catchment area, while source-orientated cartography was attempted for the catchment areas of the three different capture works used for drinking water.

  4. Sediment storage and yield in an urbanized karst watershed

    NASA Astrophysics Data System (ADS)

    Hart, Evan A.; Schurger, Stephen G.

    2005-08-01

    In karst watersheds, sinkholes and other drainage features control the temporal and spatial pattern of sediment storage across the landscape. However, studies dealing with sedimentation in karst watersheds are scarce and the sediment storage function of sinkholes and caves has not been investigated using a sediment budget approach. In this study, we use estimates of channel erosion, sinkhole sedimentation, and suspended sediment yield to examine changes in sediment storage in the 9 km 2 Upper Pigeon Roost Creek fluviokarst watershed near Cookeville, TN. The study watershed has undergone urbanization over the last ˜ 50 years, and sinkholes and caves in the area show signs of recent sedimentation (buried tree roots, buried cultural artifacts, etc.). While sinkholes are generally considered to be sediment sinks, sinkholes examined in this study are shown to cycle between periods of net sediment storage and net sediment loss. Using copyright dates on trash items buried in sinkhole deposits, we estimated the residence time of sinkhole-stored sediment to range from 6 to 10 years. However, other evidence indicates that some sinkholes may store sediment for several centuries. We propose that sediment storage within sinkholes is controlled by several factors including sinkhole drainage area, sinkhole morphology, and basin sediment yield. In addition, changes in sediment storage in karst watersheds are contingent upon random events such as sinkhole collapses. Annual sediment yield was estimated to be 111 Mg km - 2 year - 1 for the entire study watershed and ranged from 11 to 128 Mg km - 2 year - 1 for 3 sub-watersheds. Sediment eroded from the watershed, perhaps during historic settlement of the area, is stored within a large cave system underlying the city. However, the results of a partial sediment budget indicate that the cave is presently a net sediment source. Overall, the findings indicate that the sediment storage function of caves and sinkholes varies spatially and

  5. Impact of karst water on coal mining in North China

    NASA Astrophysics Data System (ADS)

    Li, Gongyu; Zhou, Wanfang

    2006-01-01

    Coalfields in North China encompass more than ten Provinces. They contain six to seven coal seams in the Permo-Carboniferous strata. The lower three seams account for 37% of the total reserves and are threatened with intrusion of karst water from the underlying Ordovician limestone. Hundreds of water inrush incidences have occurred, in which a large amount of water suddenly flows into tunnels or working faces under high potentiometric pressure. Over 50 mines have been flooded over the last 30 years. Large-scale dewatering or depressurizing of the karst aquifer was considered essential to avoid water inrushes and keep the mines safely operational. This practice, however, has caused sinkholes, dry springs, water supply shortage, and groundwater contamination in the surrounding areas. One alternative water control measure is to make full use of the rock layer between the coal seam and the karst aquifer as a protective barrier to prevent or constrain water flow from the underlying aquifer into the mines. Grouting is effective when the hydrogeological conditions are favorable to this technique. Proper design of the grouting program and experience of the contractor are also important for a successful application.

  6. How to Quantify the Quality of Karst Network Models?

    NASA Astrophysics Data System (ADS)

    Renard, P.

    2014-12-01

    In the last years, new models have been developed for the geometry of karstic conduit networks. Some are based on purely statistical techniques, others are based on process based methods. Are the resulting models properly representing the main features of real karstic systems? In this talk, we introduce a set of statistical indicators to characterize the geometry and topology of karstic networks. These indicators have been applied on a relatively large set of real karst networks. We then use these measures to compare synthetic karstic networks with their field counter parts. We use a supervised learning algorithm to automatically classify any new simulated network based on its statistical properties. Issues such as incomplete mapping of the karst system or systematic bias due to exploration conditions are discussed. We show that the method is able to estimate objectively how distant the simulated network is from the real karst networks. This distance can then be used as a quality measure of the simulation and may indicate the direction to take in order to improve future simulations.

  7. Time series analysis as a tool for karst water management

    NASA Astrophysics Data System (ADS)

    Fournier, Matthieu; Massei, Nicolas; Duran, Léa

    2015-04-01

    Karst hydrosystems are well known for their vulnerability to turbidity due to their complex and unique characteristics which make them very different from other aquifers. Moreover, many parameters can affect their functioning. It makes the characterization of their vulnerability difficult and needs the use of statistical analyses Time series analyses on turbidity, electrical conductivity and water discharge datasets, such as correlation and spectral analyses, have proven to be useful in improving our understanding of karst systems. However, the loss of information on time localization is a major drawback of those Fourier spectral methods; this problem has been overcome by the development of wavelet analysis (continuous or discrete) for hydrosystems offering the possibility to better characterize the complex modalities of variation inherent to non stationary processes. Nevertheless, from wavelet transform, signal is decomposed on several continuous wavelet signals which cannot be true with local-time processes frequently observed in karst aquifer. More recently, a new approach associating empirical mode decomposition and the Hilbert transform was presented for hydrosystems. It allows an orthogonal decomposition of the signal analyzed and provides a more accurate estimation of changing variability scales across time for highly transient signals. This study aims to identify the natural and anthropogenic parameters which control turbidity released at a well for drinking water supply. The well is located in the chalk karst aquifer near the Seine river at 40 km of the Seine estuary in western Paris Basin. At this location, tidal variations greatly affect the level of the water in the Seine. Continuous wavelet analysis on turbidity dataset have been used to decompose turbidity release at the well into three components i) the rain event periods, ii) the pumping periods and iii) the tidal range of Seine river. Time-domain reconstruction by inverse wavelet transform allows

  8. Selected Micropollutants as Indicators in a Karst Catchment

    NASA Astrophysics Data System (ADS)

    Zirlewagen, Johannes; Schiperski, Ferry; Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Scheytt, Traugott

    2015-04-01

    High flow dynamics and variations in water quality are typical for karst springs and reflect the complex interaction of different flow and storage components within a karst system. Event-based monitoring of mobile micropollutants in spring water combined with information on their input is used (1) to quantify the impact of certain contamination scenarios on spring water quality and (2) to gain additional information on the intrinsic characteristics of a karst system. We employ the artificial sweeteners acesulfame and cyclamate as source specific indicators for sewage along with the herbicides atrazine and isoproturon for agriculture. The study site is the 45 km² rural catchment of the perennial karst spring Gallusquelle in SW-Germany (mean discharge: 0.5 m³/s). Overflow events of a stormwater detention basin (SDB, combined sewer system) are known to impact water quality. Most of the sewer system is situated in the SW of the catchment. Most agricultural land is found in the NE. Neither atrazine nor significant amounts of isoproturon were detected in wastewater. Concentrations and mass fluxes of acesulfame and cyclamate in wastewater were determined. The combined evaluation of the persistent compound acesulfame with the rather degradable cyclamate allows for the distinction of long and short transit times and thus slow and fast flow components. The same applies for atrazine (persistent) and isoproturon (degradable). In Germany, acesulfame was licensed in 1990, atrazine was banned shortly after, in 1991. During low flow conditions only atrazine (max. 4 ng/L) and acesulfame (max. 20 ng/L) were detected in spring water. After a recharge event without SDB overflow concentrations as well as mass fluxes of both compounds decreased, reflecting an increasing portion of event water in spring discharge. A breakthrough of isoproturon (max. 9 ng/L) indicated the arrival of water from croplands. After a recharge event accompanied by a SDB overflow cyclamate was detected at max

  9. Interregional comparison of karst disturbance: west-central Florida and southeast Italy.

    PubMed

    North, Leslie A; van Beynen, Philip E; Parise, Mario

    2009-04-01

    The karst disturbance index (KDI) consists of 31 environmental indicators contained within the five broad categories: geomorphology, hydrology, atmosphere, biota, and cultural. The purpose of this research is to apply the KDI to two distinct karst areas, west Florida, USA, and Apulia, Italy. Through its application, the utility of the index can be validated and other important comparisons can be made, such as differences in the karst legislations implemented in each region and the effect of time exposure to human occupation to each karst terrain. Humans have intensively impacted the karst of southeast Italy for thousands of years compared to only decades in west-central Florida. However, west-central Florida's higher population density allows the region to reach disturbance levels comparable to those reached over a longer period in Apulia. Similarly, Italian karst is more diverse than the karst found in west-central Florida, creating an opportunity to test all the KDI indicators. Overall, major disturbances for southeast Italy karst include quarrying, stone clearing, and the dumping of refuse into caves, while west-central Florida suffers most from the infilling of sinkholes, soil compaction, changes in the water table, and vegetation removal. The application of the KDI allows a benchmark of disturbance to be established and later revisited to determine the changing state of human impact for a region. The highlighting of certain indicators that recorded high levels of disturbance also allows regional planners to allocate resources in a more refined manner. PMID:19135774

  10. Vulnerability of karst aquifers to agricultural contaminants: A case study in the Pennyroyal Plateau of Kentucky

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst landscapes are common in many agricultural regions in the US. Well-developed karst landscapes are characterized by shallow soils, sinkholes, sinking streams, underground conduits, and springs. In these landscapes surface runoff is minimal and most recharge enters the subsurface relatively quic...

  11. Interregional comparison of karst disturbance: west-central Florida and southeast Italy.

    PubMed

    North, Leslie A; van Beynen, Philip E; Parise, Mario

    2009-04-01

    The karst disturbance index (KDI) consists of 31 environmental indicators contained within the five broad categories: geomorphology, hydrology, atmosphere, biota, and cultural. The purpose of this research is to apply the KDI to two distinct karst areas, west Florida, USA, and Apulia, Italy. Through its application, the utility of the index can be validated and other important comparisons can be made, such as differences in the karst legislations implemented in each region and the effect of time exposure to human occupation to each karst terrain. Humans have intensively impacted the karst of southeast Italy for thousands of years compared to only decades in west-central Florida. However, west-central Florida's higher population density allows the region to reach disturbance levels comparable to those reached over a longer period in Apulia. Similarly, Italian karst is more diverse than the karst found in west-central Florida, creating an opportunity to test all the KDI indicators. Overall, major disturbances for southeast Italy karst include quarrying, stone clearing, and the dumping of refuse into caves, while west-central Florida suffers most from the infilling of sinkholes, soil compaction, changes in the water table, and vegetation removal. The application of the KDI allows a benchmark of disturbance to be established and later revisited to determine the changing state of human impact for a region. The highlighting of certain indicators that recorded high levels of disturbance also allows regional planners to allocate resources in a more refined manner.

  12. Techniques to better understand complex epikarst hydrogeology and contaminant transport in telogenetic karst settings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The movement of autogenic recharge through the shallow epikarstic zone in soil-mantled karst aquifers is important in understanding recharge areas and rates, groundwater storage, and contaminant transport processes. The groundwater flow in agricultural karst areas, such as Kentucky’s Pennyroyal Plat...

  13. Submerged karst landforms observed by multibeam bathymetric survey in Nagura Bay, Ishigaki Island, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Kan, Hironobu; Urata, Kensaku; Nagao, Masayuki; Hori, Nobuyuki; Fujita, Kazuhiko; Yokoyama, Yusuke; Nakashima, Yosuke; Ohashi, Tomoya; Goto, Kazuhisa; Suzuki, Atsushi

    2015-01-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the southern Ryukyu Islands, Japan. The coastal seafloor at depths shallower than ~ 130 m has been subjected to repeated and alternating subaerial erosion and sedimentation during periods of Quaternary sea-level lowstands. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. Although these submerged karst landforms are covered by thick postglacial reef and reef sediments, their shapes and sizes are distinct from those associated with coral reef geomorphology. The submerged landscape of Nagura Bay likely formed during multiple glacial and interglacial periods. According to our bathymetric results and the aerial photographs of the coastal area, this submerged karst landscape appears to have developed throughout Nagura Bay (i.e., over an area of approximately 6 × 5 km) and represents the largest submerged karst in Japan.

  14. Karst water: An important factor for the drinking water supply in Austria

    NASA Astrophysics Data System (ADS)

    Zötl, J. G.

    1985-12-01

    Approximately one-sixth of Austria’s land surface is karstified One-fourth of the precipitation falling in Austria lands in these karst areas, providing one-third of the population with drinking water If the projected future water needs of Austria are to be met, optimal utilization and protection of these karst water supplies is necessary To achieve these goals, community officials and civil engineers must understand the nature of karst water resources and the problems associated with their utilization At the recommendation fo the Federal Ministry for Agriculture and Forestry of the Republic of Austria, a pamphlet designed to provide this critical information has been written. The four major areas discussed in the pamphlet are definitions and descriptions of karst water flow and occurrence, discharge and physiochemical requirements for karst water supplies, requisite environmental studies of all possible sources of qualitative and/or quantitative damage to the karst water supply and engineering methods that can aid in preventing such damage, and legislative provisions necessary to protect karst water resources from water quality or quantity degradation In addition, the role of the public in karst water supply protection is discussed.

  15. Transport of free and particulate-associated bacteria in karst

    USGS Publications Warehouse

    Mahler, B.J.; Personne, J.-C.; Lods, G.F.; Drogue, C.

    2000-01-01

    Karst aquifers, because of their unique hydrogeologic characteristics, are extremely susceptible to contamination by pathogens. Here we present the results of an investigation of contamination of a karst aquifer by fecal indicator bacteria. Two wells intercepting zones with contrasting effective hydraulic conductivities, as determined by pump test, were monitored both during the dry season and in response to a rain event. Samples were also collected from the adjacent ephemeral surface Stream, which is known to be impacted by an upstream wastewater treatment plant after rainfall. Whole water and suspended sediment samples were analyzed for fecal coliforms and enterococci. During the dry season, pumping over a 2-day period resulted in increases in concentrations of fecal coliforms to greater than 10,000 CFU/100 ml in the high-conductivity well; enterococci and total suspended solids also increased, to a lesser degree. Toward the end of the pumping period, as much as 50% of the fecal coliforms were associated with suspended sediment. Irrigation of an up-gradient pine plantation with primary-treated wastewater is the probable source of the bacterial contamination. Sampling after a rain event revealed the strong influence of water quality of the adjacent Terrieu Creek on the ground water. Bacterial concentrations in the wells showed a rapid response to increased concentrations in the surface water, with fecal coliform concentrations in ground water ultimately reaching 60,000 CFU/100 ml. Up to 100% of the bacteria in the ground water was associated with suspended sediment at various times. The results of this investigation are evidence of the strong influence of surface water on ground water in karst terrain, including that of irrigation water. The large proportion of bacteria associated with particulates in the ground Water has important implications for public health, as bacteria associated with particulates may be more persistent and more difficult to inactivate. The

  16. East Chestnut Ridge hydrogeologic characterization: A geophysical study of two karst features

    SciTech Connect

    Not Available

    1991-01-01

    Permitting and site selection activities for the proposed East Chestnut Ridge landfill, located on the Oak Ridge Reservation, have required additional hydrogeologic studies of two karst features. Geophysical testing methods were utilized for investigating these karst features. The objectives of the geophysical testing was to determine the feasibility of geophysical techniques for locating subsurface karst features and to determine if subsurface anomalies exist at the proposed landfill site. Two karst features, one lacking surface expression (sinkhole) but with a known solution cavity at depth (from previous hydrologic studies), and the other with surface expression were tested with surface geophysical methods. Four geophysical profiles, two crossing and centered over each karst feature were collected using both gravimetric and electrical resistivity techniques.

  17. Change analysis of karst rocky desertification for almost 40 years: a case study of Guangxi, China

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Zhou, Guoqing; Mao, Guodong; Shi, Yujun; Zhang, Rongting; Su, Chengjie

    2015-12-01

    The paper first studied the geometric correction of historical CORONA satellite imagery in the 1960s and used the historical imagery to extract KRD (karst rocky desertification). The study area is located in the karst region of Guangxi Province, China. Finally, we used the Landsat-5 imagery to extract rocky desertification in 2005, then we could find the changes of the karst rocky desertification in Guangxi from 1960s to 2005 about nearly 40 years. And comparison analysis was conducted and the results showed that, over the 40 years, Guangxi karst rocky desertification area has significantly changed. Guangxi has typical karst environment and is one of the most serious areas of rocky desertification in southwest China provinces, thus our research on this has great practical significance.

  18. Karst Lands: The dissolution of carbonate rock produces unique landscapes and poses significant hydrological and environmental concerns

    SciTech Connect

    White, W.B.; Culver, D.C.; Herman, J.S.

    1995-09-01

    Karst lands are produced by the action of water on soluble rocks, a process among the most dynamic of all erosive forces that counterbalance the uplifting forces of tectonics. The dissolution of carbonate rock, primarily limestone and dolomite, produces unique landscapes and poses significant hydrological and environmental concerns. The major topic areas discussed in this article include the following: processes that form karst; karst drainage basins; discharge from karst aquifers; caves as paleoclimatic recorders; caves as ecosystems; water issues in karst regions; and sinkholes, soil piping and subsidence. 20 refs., 9 figs.

  19. Some Caves in tunnels in Dinaric karst of Croatia

    NASA Astrophysics Data System (ADS)

    Garasic, Mladen; Garasic, Davor

    2016-04-01

    In the last 50 years during the construction of almost all the tunnels in the Croatian Dinaric Karst thousands of caves have been encountered that represented the major problems during the construction works. Geological features (fissures, folding, faults, etc.) are described in this contribution, together with the hydrogeological conditions (rapid changes in groundwater levels). Special engineering geological exploration and survey of each cave, together with the stabilization of the tunnel ceiling, and groundwater protection actions according to basic engineering geological parameters are also presented. In karst tunneling in Croatia over 150 caves longer than 500 m have been investigated. Several caves are over 300 m deep (St. Ilija tunnel in Biokovo Mt), and 10 are longer than 1000 m (St.Rok tunnel, HE Senj and HE Velebit tunnels in Velebit Mt, Ucka tunnel in Ucka Mt, Mala kapela tunnel in Kapela Mt, caverns in HE Plat tunnel etc). Different solutions were chosen to cross the caves depending on the size and purpose of the tunnels (road, rail, pedestrian tunnel, or hydrotechnical tunnels). This is presentations of interesting examples of ceiling stabilization in big cave chambers, construction of bridges inside tunnels, deviations of tunnels, filling caves, grouting, etc. A complex type of karstification has been found in the cavern at the contact between the Palaeozoic clastic impervious formations and the Mesozoic complex of dolomitic limestones in the Vrata Tunnel and at the contact with flysch in the Učka Tunnel. However, karstification advancing in all directions at a similar rate is quite rare. The need to have the roadway and/or tunnel above water from a spring is the biggest possible engineering-geological, hydrogeological and civil engineering challenge. Significant examples are those above the Jadro spring (Mravinci tunnel) in flysch materials or above the Zvir spring in Rijeka (Katarina tunnel), and in fractured Mesozoic carbonates. Today in Croatian

  20. Turbidity dynamics of the karst spring Ombla (Croatia)

    NASA Astrophysics Data System (ADS)

    Denic-Jukic, V.; Juras, T.; Plenkovic, M.; Kadic, A.; Jukic, D.

    2012-04-01

    Hydrogeological characteristics of the karst are complex and significantly different from the characteristics of granular media. Underground structures of pores, fissures, fractures and conduits of various size and forms with significant spatial and temporal variability and discontinuity of hydraulic and geometric parameters create complex hydrogeological conditions for groundwater flow. Karst aquifers are important fresh water resources but are frequently contaminated by turbidity because of the presence of various degrees of karstified limestone with highly transmissive conduits. Many analyses have shown that the period of turbidity represents the period of increased water pollution with bacteria. The present study presents the Ombla spring karstic system (Dubrovnik, Croatia). The Ombla Spring is located at an elevation of 2.5 m above sea-level and the river immediately flows into the Adriatic Sea. The water from the Ombla Spring is used for the water supply for the city of Dubrovnik. The precipitation regime is changeable. The average annual rainfall measured in Dubrovnik was 1220 mm. At Vukovići raingauge station, 7 km away, it amounted to 1800 mm and at the Hum raingauge station, 12.5 km from Dubrovnik it reached 2100 mm. The method applied is based essentially on time series analysis which has wide application in hydrogeological system analysis. A simple analysis gave a definition of the pattern signals of three types of records: rainfall, discharge rate and turbidity. Cross-correlation and spectral analysis were made between rainfall and discharge rates that were considered to be input signal and turbidity values which were considered to be the output signal. Both the simple and cross-analysis were made taking into account time and frequency domain. Analyzing turbidity as additional output signal parameter and parallel analysis of two responses reveals additional valuable information about the karst spring functioning. Turbidity of water in the Ombla karst

  1. Fate and Transport of TCE Solvents Through Saturated Karst Aquifer

    NASA Astrophysics Data System (ADS)

    Padilla, I. Y.; Carmona, M.; Anaya, A. A.

    2014-12-01

    Dense Nonaqueous-Phase Liquids (DNAPLs) are a group of organic compounds that have been a serious problem for groundwater pollution in karst. The industrial production and utilization of these chemicals spread since 1940, and are present at tens of thousands of contaminated sites worldwide. The physic-chemical properties of DNAPLs in conjunction with the hydraulic properties of the karst systems create the perfect condition for DNAPLs to penetrate the epikarst, reach the groundwater, and more within the karst system to zones of potential exposure, such as wells, streams and wetlands. Trichloroethylene (TCE) is the most common DNPAL found in the subsurface environment. This research studies the fate and transport of TCE DNAPL in a karstified limestone physical model (KLPM). Experiments are carried out in KLPM. The KLPM is an enclosed stainless steel tank packed with a rectangular limestone block (15cm x 15cm x 76cm) that simulates a saturated confine karst aquifer. DNAPL experiment involve the injection of 40 ml of pure TCE into steady groundwater flow at the upstream boundary of the KLPM model, while sampling spatially and temporally along the block. Samples are analyzed for TCE on the pure and dissolved phase. Pure TCE is analyzed volumetrically and dissolved phase concentrations are analyze using a High Performance Liquid Chromatography (HPLC). TCE data is used to construct temporal distributions curves (TDCs) at different spatial locations. Results show that pure TCE volumes are collected at the beginnings of the experiment in sampling ports located near the injection port and along preferential flow paths. TCE concentration TDCs show spatial variations related to the limestone block heterogeneously. Rapid response to TCE concentrations is associated with preferential flow paths. Slow response and long tailing of TCE of TCE concentration are associated with diffusive transport in rock matrix and mass transport rates limitations. Bimodal distributions are

  2. Analysis of the maximum discharge of karst springs

    NASA Astrophysics Data System (ADS)

    Bonacci, Ognjen

    2001-07-01

    Analyses are presented of the conditions that limit the discharge of some karst springs. The large number of springs studied show that, under conditions of extremely intense precipitation, a maximum value exists for the discharge of the main springs in a catchment, independent of catchment size and the amount of precipitation. Outflow modelling of karst-spring discharge is not easily generalized and schematized due to numerous specific characteristics of karst-flow systems. A detailed examination of the published data on four karst springs identified the possible reasons for the limitation on the maximum flow rate: (1) limited size of the karst conduit; (2) pressure flow; (3) intercatchment overflow; (4) overflow from the main spring-flow system to intermittent springs within the same catchment; (5) water storage in the zone above the karst aquifer or epikarstic zone of the catchment; and (6) factors such as climate, soil and vegetation cover, and altitude and geology of the catchment area. The phenomenon of limited maximum-discharge capacity of karst springs is not included in rainfall-runoff process modelling, which is probably one of the main reasons for the present poor quality of karst hydrological modelling. Résumé. Les conditions qui limitent le débit de certaines sources karstiques sont présentées. Un grand nombre de sources étudiées montrent que, sous certaines conditions de précipitations extrêmement intenses, il existe une valeur maximale pour le débit des sources principales d'un bassin, indépendante des dimensions de ce bassin et de la hauteur de précipitation. La modélisation des débits d'exhaure d'une source karstique n'est pas facilement généralisable, ni schématisable, à cause des nombreuses caractéristiques spécifiques des écoulements souterrains karstiques. Un examen détaillé des données publiées concernant quatre sources karstiques permet d'identifier les raisons possibles de la limitation de l'écoulement maximal: (1

  3. Colonization by aerobic bacteria in karst: laboratory and in situ experiments.

    PubMed

    Personné, J C; Poty, F; Mahler, B J; Drogue, C

    2004-01-01

    Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton.

  4. Colonization by aerobic bacteria in karst: Laboratory and in situ experiments

    USGS Publications Warehouse

    Personne, J.-C.; Poty, F.; Mahler, B.J.; Drogue, C.

    2004-01-01

    Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton.

  5. Evidence for Bacterial Sulfate Reduction in a Fissured-porous Karst System in Southern Germany

    NASA Astrophysics Data System (ADS)

    Einsiedl, F.; Mayer, B.

    2005-12-01

    Twenty five percent of the world's population uses karst water as drinking water resources. Since karst groundwater systems are highly vulnerable to contamination, groundwater protection and self purification is a major challenge. Up to now research in karst groundwater systems has predominantly concentrated on hydrodynamic processes. Little is known about anoxic processes in oxygen dominated, fracture-matrix diffusion controlled karst aquifers. Isotope measurements comprise a promising tool to identify biogeochemical processes such as bacterial (dissimilatory) sulfate reduction in karstic aquifers. The goal of this study was to determine the sources and the processes affecting sulfate in an oxygen-rich karst aquifer in southern Germany and their dependence on hydrogeological parameters. This was achieved by interpreting tritium data with a simple lumped parameter approach and assessing variations in concentrations and isotopic compositions of sulfate and dissolved inorganic carbon (DIC) with respect to groundwater age. Young groundwater (<30 years) was characterized by comparatively high sulfate concentrations (0.36 mM) and δ34S values similar to those of recent atmospheric deposition (1.5‰). In contrast groundwater with mean residence times >60 years had significantly lower sulfate concentrations (0.08 mM) and markedly higher δ34S values (7.5‰). These results indicate that in karst systems with matrix porosity, bacterial (dissimilatory) sulfate reduction may occur. This process has the potential to contribute to long-term biodegradation of contaminants in the porous rock matrix representing the dominant water reservoir in fissured-porous karst aquifers.

  6. Karst of the Mid-Atlantic region in Maryland, West Virginia, and Virginia

    USGS Publications Warehouse

    Doctor, Daniel H.; Weary, David J.; Brezinski, David K.; Orndorff, Randall C.; Spangler, Lawrence E.; Brezinski, David K.; Halka, Jeffrey; Ortt, Richard A.

    2015-01-01

    The Mid-Atlantic region hosts some of the most mature karst landscapes in North America, developed in highly deformed rocks within the Piedmont and Valley and Ridge physiographic provinces. This guide describes a three-day excursion to examine karst development in various carbonate rocks by following Interstate 70 west from Baltimore across the eastern Piedmont, across the Frederick Valley, and into the Great Valley proper. The localities were chosen in order to examine the structural and lithological controls on karst feature development in marble, limestone, and dolostone rocks with an eye toward the implications for ancient landscape evolution, as well as for modern subsidence hazards. A number of caves will be visited, including two commercial caverns that reveal strikingly different histories of speleogenesis. Links between karst landscape development, hydrologic dynamics, and water resource sustainability will also be emphasized through visits to locally important springs. Recent work on quantitative dye tracing, spring water geochemistry, and groundwater modeling reveal the interaction between shallow and deep circulation of groundwater that has given rise to the modern karst landscape. Geologic and karst feature mapping conducted with the benefit of lidar data help reveal the strong bedrock structural controls on karst feature development, and illustrate the utility of geologic maps for assessment of sinkhole susceptibility.

  7. [Microbial community abundance and diversity in typical karst ecosystem to indicate soil carbon cycle].

    PubMed

    Jin, Zhen-Jiang; Tang, Hua-Feng; Li, Min; Huang, Bing-Fu; Li, Qiang; Zhang, Jia-Yu; Li, Gui-Wen

    2014-11-01

    The soil microbial characteristics were detected to clarify their indications in organic carbon cycle in karst system. Soil samples from three karst types (saddle, depression and slop) at 0-10 cm, 10-20 cm and 20-30 cm layers were collected in the Yaji Karst Experimental Site, a typical karst ecosystem. The microbial diversity and abundance were assayed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and fluorescence quantitative PCR. The data showed that the highest abundance of 16S rRNA and 18S rRNA were in depression with 1.32 x 10(11) copies x g(-1) and in saddle with 1.12 x 10(10) copies x g(-1), respectively. The abundance of 16S rRNA in saddle and depression decreased from top to bottom, while that of 18S rRNA in three karst forms decreased, which showed that the abundance changed consistently with soil organic carbon (SOC). The 3 diversity indices of 16S rRNA and 6 diversity indices of 18S rRNA increased from top to bottom in soil profiles of three karst forms. These results showed that microbial diversity changed conversely with the abundance and SOC in soil profile. It can be concluded that the abundance was more important than the diversity index for soil carbon cycle in karst system.

  8. Hazard connected to tunnel construction in Mt Stena karstic area (Rosandra Valley, Classical Karst)

    NASA Astrophysics Data System (ADS)

    Cucchi, F.; Boschin, W.; Visintin, L.; Zini, L.

    2009-04-01

    Rosandra Valley -a unique geomorphological environment- is located in the western side of the Classical Karst plateau. This deep limestone gorge is crossed by a stream that is fed by a large basin located in Slovenia. Rosandra Valley is the only example of Classical Karst river valley with surface hydrography; the torrent digs a deep gully into the rock, rich in rapids, swirl holes, small waterfalls, enclosed meanders and basins; here, the first seepage phenomena occur, and part of the water feeds the underground aquifer. Rosandra Valley is theatre to complex structural situation; the NE slope culminates in the structure of Mt Stena, a limestone tectonic scale located between two faults and firmly rooted in the karst platform. Tectonics is quite important for the development of deep karst in this area; Mt Stena, in particular, hosts a comprehensive net of articulated and diversely shaped caves, basically organised on several levels, which stretches over a total of 9,000 metres, bearing testimony to ancient geological and hydrogeological origins. The deepest areas of the system reach a suspended aquifer that is probably sustained by an overthrust and placed about 100 meters above Rosandra torrent underground aquifer. During feasibility studies about Trieste-Divača high velocity railway link, interaction between project and karst features was examined; in fact the proximity of proposal project and Mt Stena karst system suggest to improve the knowledge related to karst and hydrogeological aspects of the massif. Compatibly with the project requirements, risk of voids intersection and water contamination were analyzed. In fact the Mt Stena suspended aquifer partially feeds Rosandra torrent which flows in a protected natural area. Karst features were represented in a 3D model in order to better understand the spatial relationship between railway project and karst system.

  9. Karst hazard assessment in the design of the main gas pipeline (South Yakutia)

    NASA Astrophysics Data System (ADS)

    Strokova, L. A.; Dutova, E. M.; Ermolaeva, A. V.; Alimova, I. N.; Strelnikova, A. B.

    2015-11-01

    The paper represents the description of the zonal and regional geological factors of geoengineering conditions which characterize the territory in South Yakutia crossed by the designed main gas pipeline. Cryogenic processes and karst are considered to be the most dangerous hazards for gas pipeline maintenance. Karst hazard assessment of the gas pipeline section made in the course of the research has involved a complex of geological methods: geoengineering, geophysical, hydrogeological, and mapping. Sections prone to karst development have been identified. The authors have suggested the measures to protect potentially hazardous sections and to ensure timely informing on sinkhole collapses.

  10. Karst and artificial recharge: Theoretical and practical problems. A preliminary approach to artificial recharge assessment

    NASA Astrophysics Data System (ADS)

    Daher, Walid; Pistre, Séverin; Kneppers, Angeline; Bakalowicz, Michel; Najem, Wajdi

    2011-10-01

    SummaryManaged Aquifer Recharge (MAR) is an emerging sustainable technique that has already generated successful results and is expected to solve many water resource problems, especially in semi-arid and arid zones. It is of great interest for karst aquifers that currently supply 20-25% of the world's potable water, particularly in Mediterranean countries. However, the high heterogeneity in karst aquifers is too complex to be able to locate and describe them simply via field observations. Hence, as compared to projects in porous media, MAR is still marginal in karst aquifers. Accordingly, the present work presents a conceptual methodology for Aquifer Rechargeability Assessment in Karst - referred to as ARAK. The methodology was developed noting that artificial recharge in karst aquifers is considered an improbable challenge to solve since karst conduits may drain off recharge water without any significant storage, or recharge water may not be able to infiltrate. The aim of the ARAK method is to determine the ability of a given karst aquifer to be artificially recharged and managed, and the best sites for implementing artificial recharge from the surface. ARAK is based on multi-criteria indexation analysis modeled on karst vulnerability assessment methods. ARAK depends on four independent criteria, i.e. Epikarst, Rock, Infiltration and Karst. After dividing the karst domain into grids, these criteria are indexed using geological and topographic maps refined by field observations. ARAK applies a linear formula that computes the intrinsic rechargeability index based on the indexed map for every criterion, coupled with its attributed weighting rate. This index indicates the aptitude for recharging a given karst aquifer, as determined by studying its probability first on a regional scale for the whole karst aquifer, and then by characterizing the most favorable sites. Subsequently, for the selected sites, a technical and economic feasibility factor is applied, weighted

  11. Comparative analysis of surface soil moisture retrieval using VSWI and TVDI in karst areas

    NASA Astrophysics Data System (ADS)

    Yan, Hongbo; Zhou, Guoqing; Lu, Xianjian

    2015-12-01

    Vegetation Supply Water Index (VSWI) and Temperature Vegetation dryness Index (TVDI) are two most commonly used methods for surface soil moisture (SSM) retrieval using electromagnetic spectrum of visible, near infrared and thermal infrared band. Both of them take into account the effect of vegetation index (VI) and surface temperature (Ts) on SSM. A comparative analysis of the ability and effect of the two methods for SSM retrieval in karst areas was carried out, using the remote sensing data of Landsat 8 OLI_TIRS. The study area is located in Guilin, which is a typical karst area. The experimental results show that TVDI is more suitable for SSM retrieval in karst areas.

  12. Classification of thermal patterns at karst springs and cave streams.

    PubMed

    Luhmann, Andrew J; Covington, Matthew D; Peters, Andrew J; Alexander, Scott C; Anger, Cale T; Green, Jeffrey A; Runkel, Anthony C; Alexander, E Calvin

    2011-01-01

    Thermal patterns of karst springs and cave streams provide potentially useful information concerning aquifer geometry and recharge. Temperature monitoring at 25 springs and cave streams in southeastern Minnesota has shown four distinct thermal patterns. These patterns can be divided into two types: those produced by flow paths with ineffective heat exchange, such as conduits, and those produced by flow paths with effective heat exchange, such as small fractures and pore space. Thermally ineffective patterns result when water flows through the aquifer before it can equilibrate to the rock temperature. Thermally ineffective patterns can be either event-scale, as produced by rainfall or snowmelt events, or seasonal scale, as produced by input from a perennial surface stream. Thermally effective patterns result when water equilibrates to rock temperature, and the patterns displayed depend on whether the aquifer temperature is changing over time. Shallow aquifers with seasonally varying temperatures display a phase-shifted seasonal signal, whereas deeper aquifers with constant temperatures display a stable temperature pattern. An individual aquifer may display more than one of these patterns. Since karst aquifers typically contain both thermally effective and ineffective routes, we argue that the thermal response is strongly influenced by recharge mode.

  13. Karst processes evidences on a Martian evaporite Dome

    NASA Astrophysics Data System (ADS)

    Baioni, D.; Zupan Hajna, N.; Wezel, F. C.

    2009-04-01

    In the eastern part of Tithonium Chasma (Mars) a body displaying a dome shape morphology is located. According to OMEGA mineralogical data (OMEGA data orbit 531_3) and further studies the dome appears to consist of kieserite, an evaporitic mineral also found on the Earth. Previous works highlighted the presence on the dome surface of karst-like landforms and morphologies that strongly resemble the evaporitic karst morphologies found on the Earth. Through the analysis of the new MRO HIRISE images we have investigated the Martian landform and the possible processes involved in their formation and shaping in great detail. The results of our study out show that the landforms observed clearly indicate the presence of solutional processes that also acted in a selective way just as in the evaporite rocks on the Earth. The analysis carried out highlight that the Martian dome can be also formed of different materials with different solutional proprieties. The dome quite probably it is constituted mainly by salts such as carnallite, kainite and halite (a mineral without spectral signatures that might be present in the dome). Our observation also suggest that on the dome liquid water must have existed in the past for enough time so that the solution features we investigated could be formed.

  14. Application of a karst disturbance index in Hillsborough County, Florida.

    PubMed

    van Beynen, Philip; Feliciano, Nilda; North, Leslie; Townsend, Kaya

    2007-02-01

    Hillsborough County, Florida, is a karst region that is heavily urbanized, yet no study has been undertaken measuring the degree of human disturbance. Van Beynen and Townsend (2005) created a hierarchical and standardized disturbance index specifically designed for karst environments. To address the problem of determining human disturbance in the county, the above index was successfully applied and it was found that Hillsborough was highly disturbed (disturbance score of 0.69 of 1.0) because of its predominant urban and rural land use. Furthermore, the application of the index allowed for its refinement and the highlighting of environmental aspects in need of remediation such as soil compaction, deforestation, disturbance of archaeological sites, and the expanding urban footprint. Several minor issues arose during the application: the need for broader indicator descriptions that encompass a variety of scenarios, the need for a revised water quality indicator, inadequate data on sinkholes, and a lack of data for species richness and species population density. The utility of the index to resource managers arises from emphasizing certain areas of the environment that require immediate attention and determining temporal changes in environmental quality. Future application of the index requires potential retooling of the biota indicators, tightening of scoring descriptions for certain indicators, and further examination of the scale at which the index can be applied.

  15. Morphometric techniques for orientation analysis of karst in northern Florida

    SciTech Connect

    Jenkins, D.T.; Beck, B.F.

    1985-01-01

    Morphometric techniques for the analysis of karst landscape orientation data based on swallet catchment areas can be highly inadequate. The long axes of catchment areas may not coincide with structural control, especially in regions having very low relief. Better structural correlation was observed using multiply linear trend measurements of closed depressions rather than drainage basins. Trend analysis was performed on four areas, approximately 25 km/sup 2/ each, forming a sequence from the Suwannee River to the Cody Escarpment in northern Florida. This area is a karst plain, mantled by 12 to 25 meters of unconsolidated sands and clays. Structural control was examined by tabulating the azimuths of distinct linear trends as determined from depression shape based on 1:24,000 topographic maps. The topography was characterized by 1872 individual swallet catchment areas or 1457 closed depressions. The common geomorphic technique of analyzing orientation data in 10/sup 0/ increments beginning with O/sup 0/ may yield incorrect peak width and placement. To correctly detect all significant orientation peaks all possible combinations of peak width and placement must be tested. Fifty-five different plots were reviewed and tested for each area.

  16. Classification of Thermal Patterns at Karst Springs and Cave Streams

    USGS Publications Warehouse

    Luhmann, A.J.; Covington, M.D.; Peters, Albert J.; Alexander, S.C.; Anger, C.T.; Green, J.A.; Runkel, Anthony C.; Alexander, E.C.

    2011-01-01

    Thermal patterns of karst springs and cave streams provide potentially useful information concerning aquifer geometry and recharge. Temperature monitoring at 25 springs and cave streams in southeastern Minnesota has shown four distinct thermal patterns. These patterns can be divided into two types: those produced by flow paths with ineffective heat exchange, such as conduits, and those produced by flow paths with effective heat exchange, such as small fractures and pore space. Thermally ineffective patterns result when water flows through the aquifer before it can equilibrate to the rock temperature. Thermally ineffective patterns can be either event-scale, as produced by rainfall or snowmelt events, or seasonal scale, as produced by input from a perennial surface stream. Thermally effective patterns result when water equilibrates to rock temperature, and the patterns displayed depend on whether the aquifer temperature is changing over time. Shallow aquifers with seasonally varying temperatures display a phase-shifted seasonal signal, whereas deeper aquifers with constant temperatures display a stable temperature pattern. An individual aquifer may display more than one of these patterns. Since karst aquifers typically contain both thermally effective and ineffective routes, we argue that the thermal response is strongly influenced by recharge mode. ?? 2010 The Author(s). Journal compilation ?? 2010 National Ground Water Association.

  17. Subsidence of residual soils in a karst terrain

    SciTech Connect

    Drumm, E.C.; Kane, W.F.; Ben-Hassine, J.; Scarborough, J.A. ); Ketelle, R.H. )

    1990-06-01

    Siting and operating landfills for solid waste disposal in eastern Tennessee that can operate with minimum impact on groundwater is problematic. The operational requirement of thick, excavational soils and the regulatory requirement of a buffer between disposal units and an aquifer result in siting most operating East Tennessee landfills in outcrop areas of the Knox Group. However, the common occurrence of karst terrain and sinkholes in the Knox Group indicates the vulnerability of such sites to rapid groundwater recharge and flow and the potential for subsidence or collapse of soil into bedrock cavities. To address the potential for subsidence or collapse of soils at the East Chestnut Ridge site on the Department of Energy's (DOE) Oak Ridge Reservation (ORR), the following activities and analyses were completed: The locations of karst features on the site were determined by field reconnaissance; several sinkholes were selected for detailed examination; soil boring, sampling, and physical testing were performed in soils located within, adjacent to, and outside of sinkholes to characterize soil strength at various depths; detailed plane surveys were made for 11 sinkholes to measure accurately their dimension and shape for use in determining profile functions for subsidence basins at the site; The stress-deformation response of a typical soil profile overlying a hypothetical bedrock cavity was analyzed numerically for a range of soil thickness and a range of cavity radii. A consistent estimate of the relationship between subsidence basin dimension, soil thickness, and cavity radius has been derived. 30 refs., 41 figs., 7 tabs.

  18. Spatial organization of the impulse response in a karst aquifer

    NASA Astrophysics Data System (ADS)

    Delbart, C.; Valdés, D.; Barbecot, F.; Tognelli, A.; Couchoux, L.

    2016-06-01

    Karst aquifers are characterized by a strong heterogeneity in their physical properties. The purpose of the study is the spatial variability of water transfers in a carbonated karstic aquifer. To this end, a high spatial density of information about the water transfer is needed. The characteristics of the site, a topographic hill of 13 km2 with eight boreholes, which was monitored hourly over four years, allows the study of the spatial variability of water transfers. The variability of the impulse response of the system is studied using autocorrelation and cross-correlation analysis between the rainfall and piezometric level time series. The shapes of the autocorrelation and cross-correlation functions vary according to the geographical location of the boreholes, that proves a spatial organization of the groundwater transfer. The response time varies depending on the thickness of the unsaturated zone by an unusual inverse correlation. In this case, the water level signal spatially integrates the signal transfer of the unsaturated zone and the signal transfer of the saturated part of the aquifer. Consequently, inertia and response time increased with the distance between the borehole and the top of piezometric dome. This description supports highly organized fast transfers in this karst aquifer and a highly connected fracture network.

  19. [Theoretical model for rocky desertification control in karst area].

    PubMed

    Liang, Liang; Liu, Zhi-Xiao; Zhang, Dai-Gui; Deng, Kai-Dong; Zhang, You-Xiang

    2007-03-01

    Based on the basic principles of restoration ecology, the trigger-action model for rocky desertification control was proposed, i. e. , the ability that an ecosystem enables itself to develop was called dominant force, and the interfering factor resulting in the deviation of the climax of ecological succession from its preconcerted status was called trigger factor. The ultimate status of ecological succession was determined by the interaction of dominant force and trigger factor. Rocky desertification was the result of serious malignant triggers, and its control was the process of benign triggers in using the ecological restoration method of artificial designs to activate the natural designing ability of an ecosystem. The ecosystem of Karst rocky desertification in Fenghuang County with restoration measures was taken as a case to test the model, and the results showed that the restoration measures based on trigger-action model markedly improved the physical and chemical properties of soil and increased the diversity of plant. There was a benign trigger between the restoration measures and the Karst area. The rationality of the trigger-action model was primarily tested by the results in practice. PMID:17552199

  20. Using stormwater hysteresis to characterize karst spring discharge.

    PubMed

    Toran, Laura; Reisch, Chad E

    2013-01-01

    Discharge from karst springs contains a mixture of conduit and matrix water, but the variations in groundwater mixing are poorly known. Storm events present an opportunity to try to map flow components because water entering during storms is more dilute and provides a tracer as it mixes with pre-event water along the flowpath from the recharge area to discharge at a spring. We used hysteresis plots of Mg/Ca ratios in a spring in the Cumberland Valley of Pennsylvania to map conduit (higher Ca) vs. diffuse (higher Mg) sources of recharge. We observed two types of temporal heterogeneity: within a storm event and from storm to storm. The timing of the variation in Mg/Ca suggested sources of mixing waters. An increase in the Mg/Ca ratio at the beginning of some storms while conductivity declined suggested diffuse recharge through the epikarst. The rapid changes in Mg/Ca ratios for low-intensity events probably occurred as the rainfall waxed and waned and illustrate that a variety of flowpaths are available at this spring because additional flushing of Mg occurred. In contrast, the conductivity hysteresis began with dilute water initially and rotation was similar from storm to storm. Hysteresis plots of the Mg/Ca ratio have the potential of revealing more of the complexity in discharge than conductivity alone. A better understanding of flow components in karst is needed to protect these aquifers as a groundwater resource. PMID:22974348

  1. Peculiarity and vulnerability of karst settings, analyzed through a review of available environmental indices

    NASA Astrophysics Data System (ADS)

    Parise, Mario; Mazzei, Marianna

    2016-04-01

    Karst is a unique environment on Earth, characterized by a variety of peculiar geological and hydrological features, that are expressed by typical landforms at the surface (doline, ponor, polje, etc.) and underground (single cave, sinkhole, complex hypogean systems consisting of sequences of pits and galleries, etc.). Among the main characters of karst, the direct connection between the surface and the underground is at the origin of the fragility of karst settings, and the related high vulnerability. Many different types of natural geological hazards (or geo-hazards) may potentially affect karst lands, with sinkholes and flash floods being the most frequent and typical. In addition, karst is exposed to a variety of anthropogenic disturbances as well, including loss of natural landscapes, destruction of caves and speleothems, and contamination and pollution problems. At this latter regard, it has to be reminded that karst aquifers host high quality groundwaters, that are used as source of drinking water worldwide, with estimates indicating that the supply of drinking water from karst is going to have a significant increase in the next decades, From all of this, the importance in fully defining the karst setting, and in a detail examination of all the natural and anthropogenic events that may cause negative effects on it, comes out. Uniqueness of karst has been acknowledged since a long time, but only in recent years efforts have been made to develop approaches and methods specifically dedicated to this peculiar environment. Such approaches represent definitely a mandatory step in the correct management of karst terranes, providing useful elements to stakeholders, land managers and people living in karst lands about their fragility, and the need to safeguard them and the natural resources therein contained. Starting from these considerations, in this contribution we review the main environmental indices dedicated to karst that have been recently proposed in the

  2. The current status of mapping karst areas and availability of public sinkhole-risk resources in karst terrains of the United States

    NASA Astrophysics Data System (ADS)

    Kuniansky, Eve L.; Weary, David J.; Kaufmann, James E.

    2016-05-01

    Subsidence from sinkhole collapse is a common occurrence in areas underlain by water-soluble rocks such as carbonate and evaporite rocks, typical of karst terrain. Almost all 50 States within the United States (excluding Delaware and Rhode Island) have karst areas, with sinkhole damage highest in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania. A conservative estimate of losses to all types of ground subsidence was 125 million per year in 1997. This estimate may now be low, as review of cost reports from the last 15 years indicates that the cost of karst collapses in the United States averages more than 300 million per year. Knowing when a catastrophic event will occur is not possible; however, understanding where such occurrences are likely is possible. The US Geological Survey has developed and maintains national-scale maps of karst areas and areas prone to sinkhole formation. Several States provide additional resources for their citizens; Alabama, Colorado, Florida, Indiana, Iowa, Kentucky, Minnesota, Missouri, Ohio, and Pennsylvania maintain databases of sinkholes or karst features, with Florida, Kentucky, Missouri, and Ohio providing sinkhole reporting mechanisms for the public.

  3. The current status of mapping karst areas and availability of public sinkhole-risk resources in karst terrains of the United States

    USGS Publications Warehouse

    Kuniansky, Eve L.; Weary, David J.; Kaufmann, James E.

    2016-01-01

    Subsidence from sinkhole collapse is a common occurrence in areas underlain by water-soluble rocks such as carbonate and evaporite rocks, typical of karst terrain. Almost all 50 States within the United States (excluding Delaware and Rhode Island) have karst areas, with sinkhole damage highest in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania. A conservative estimate of losses to all types of ground subsidence was $125 million per year in 1997. This estimate may now be low, as review of cost reports from the last 15 years indicates that the cost of karst collapses in the United States averages more than $300 million per year. Knowing when a catastrophic event will occur is not possible; however, understanding where such occurrences are likely is possible. The US Geological Survey has developed and maintains national-scale maps of karst areas and areas prone to sinkhole formation. Several States provide additional resources for their citizens; Alabama, Colorado, Florida, Indiana, Iowa, Kentucky, Minnesota, Missouri, Ohio, and Pennsylvania maintain databases of sinkholes or karst features, with Florida, Kentucky, Missouri, and Ohio providing sinkhole reporting mechanisms for the public.

  4. Praxisorientierter Ansatz zur kartographischen Darstellung von Karst-Grundwasserressourcen. Erfahrungen aus dem SWISSKARST-Projekt A practical approach for mapping karst groundwater resources

    NASA Astrophysics Data System (ADS)

    Malard, Arnauld; Jeannin, Pierre-Yves; Sinreich, Michael; Weber, Eric; Vouillamoz, Jonathan; Eichenberger, Urs

    2014-12-01

    In spite of their abundant water resources, in Switzerland as well as in other countries, the location and extent of karst aquifers have not yet been systematically studied and documented - mainly due to the lack of systematic and dedicated approaches for their characterization. In the framework of a project aiming at documenting the karst aquifers in Switzerland (SWISSKARST Project) the pragmatic KARSYS approach has been developed to systematically assess the main characteristics of karst aquifers and karst systems. One part of this project deals with the development of a practical method for mapping 2D hydrogeological karst systems, which is designed to address both scientific and applied issues. A series of maps based on the approach is proposed to describe the main characteristics of karst groundwater systems resulting in a synthesized map which suitably combines all relevant information.

  5. Modeling Flow and Pollutant Transport in a Karst Watershed with SWAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst hydrology is characterized by multiple springs, sinkholes, and losing streams resulting from acidic water percolating through limestone. These features provide direct connections between surface water and groundwater and increase the risk of groundwater, springs and stream contamination. Anthr...

  6. Possibilities and Challenges for Modeling Flow and Pollutant Transport in a Karst Watershed with SWAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Karst hydrology is characterized by multiple springs, sinkholes, and losing streams resulting from acidic water percolating through limestone. These features provide direct connections between surface water and groundwater and increase the risk of groundwater, spring and stream contamination. Anthro...

  7. Vulnerability mapping and protection zoning of karst springs. Validation by multitracer tests.

    PubMed

    Marín, A I; Andreo, B; Mudarra, M

    2015-11-01

    Protection zoning of karst springs and wells used for water supply is a key aspect in many countries, calling for specific methodologies adapted to the particular characteristics of karst media. This work presents a new approach, in view of the present state of the art and based on experiences with contamination vulnerability mapping at the pilot site of the Villanueva del Rosario karst system (southern Spain). Source (intrinsic) vulnerability maps were prepared and compared using three European procedures for karst aquifers. The vulnerability maps were then tested using dye tracers. The COP+K method and Slovene Approach appear to provide reliable results in terms of intrinsic vulnerability mapping. Nevertheless, all the methods have a margin of error. The COP+K map is adopted as the baseline to delineate the protection zones, through the conversion from vulnerability classes to degrees of protection.

  8. Vulnerability mapping and protection zoning of karst springs. Validation by multitracer tests.

    PubMed

    Marín, A I; Andreo, B; Mudarra, M

    2015-11-01

    Protection zoning of karst springs and wells used for water supply is a key aspect in many countries, calling for specific methodologies adapted to the particular characteristics of karst media. This work presents a new approach, in view of the present state of the art and based on experiences with contamination vulnerability mapping at the pilot site of the Villanueva del Rosario karst system (southern Spain). Source (intrinsic) vulnerability maps were prepared and compared using three European procedures for karst aquifers. The vulnerability maps were then tested using dye tracers. The COP+K method and Slovene Approach appear to provide reliable results in terms of intrinsic vulnerability mapping. Nevertheless, all the methods have a margin of error. The COP+K map is adopted as the baseline to delineate the protection zones, through the conversion from vulnerability classes to degrees of protection. PMID:26093222

  9. Applicability of Supercritical CO2 Speleogenesis to Exo-Planetary Karst Systems

    NASA Astrophysics Data System (ADS)

    Decker, D. D.; Polyak, V. J.; Asmerom, Y.

    2015-10-01

    Supercritical CO2 hypogene speleogenesis and its applications to exo-planetary karst features are discussed. What to look for on the planet's surface to find these types of caves and their possible use is also visited.

  10. Evolution of collapse valleys in karst - examples from the Carpatho-Balkanides of Serbia

    NASA Astrophysics Data System (ADS)

    Petrović, Aleksandar S.; Ćalić, Jelena; Spalević, Aleksandra; Pantić, Marko

    2016-04-01

    Development of valleys in karst is an issue which has not been sufficiently studied in karst surface morphology. THESE valleys are long linear forms whose orthogonal projections resemble normal valleys, but most of their characteristics are strongly influenced by karst process. In largest number of relevant references, this subject is either only briefly mentioned or completely lacking. This paper presents the examples of a particular type of valley in karst formed by cave ceiling collapse close to the topographical surface. Karst of the Carpatho-Balkanides in eastern Serbia is characterized by uneven spatial distribution in several large massifs, but also in a large number of relatively small outcrops (patches and belts), which enable the development of contact karst and fluviokarst. Many morphological elements are of fluvial origin, subsequently modified by karst process. Collapse valleys occur mostly at the downstream contacts (where a seasonal watercourse leaves limestones) or in karst/limestone belts. In the first phase, which is visible on the example of the Radovanska Reka, the river course sinks to the swallets in the riverbed and forms a blind valley. After sinking, the water flows through the tunnel cave, while largest part of the valley remains above the cave. The bottom of the dry valley is dissected by deep dolines, reaching almost to the cave roof. In this part of the study, the area was scanned by a multistation Leica Nova MS 50 (resolution 20 cm @ 10 m). In the second phase, the doline bottoms reach the cave ceilings which develop holes at certain points, as it is case at the Zamna River valley. These hollows tend to enlarge with time, and the surface of the cave ceiling is reduced. The third, final phase is characterised by collapse of larger segments of cave ceilings. Only the natural bridges remain, as the remnants of former caves (e.g. in the Vratna River valley, Ravna Reka valley). These parts of valleys in karst are usually narrow, steep

  11. Influence of karst genesis on aperture distributions determined by means of numerical modelling

    NASA Astrophysics Data System (ADS)

    Hubinger, B.; Birk, S.

    2009-04-01

    A considerable portion of the global drinking water supply originates from karst aquifers. However, karst waters often suffer from high vulnerability concerning contaminants due to the inherent characteristics of the aquifers, namely the rapid contaminant transport through solution conduits. Generic research on karst aquifers helps understanding how the processes of karstification determine the transport properties of the conduit systems. Karst spring responses to precipitation events, isotopic measurements and tracer tests typically suggest different flow paths across the aquifers including very diverse residence times of solutes. Residence times are evidently dependent on the structure of the conduit system and the size of the openings. Yet direct field investigation provides only limited information about the properties of the conduit system. Thus, field investigations may be complemented by modelling of the evolution of conduit systems (karst genesis). In this work, a numerical model simulating karst genesis is used to investigate factors controlling the aperture distribution in karst aquifers. The karst aquifer is conceptualized as a network of different discrete, hydraulically connected and water filled voids representing solution conduits. The water flow and the dissolution rates are calculated for individual solution conduits and the conduits are widened accordingly. The dissolutional widening of the apertures from the mm-range (and below) to the range of several metres is studied with respect to the influences of geological and hydrological boundary conditions. Variations of the initial aperture distributions lead to differences in the hydraulic conductivity throughout the aquifer and consequently the evolution of different preferred flow paths. Therefore, different scenarios representing very homogeneous to very heterogeneous networks are considered. At the early stage of karst evolution a fixed hydraulic gradient is assumed. Yet this leads to

  12. Application of dye-tracing techniques for determining solute-transport characteristics of ground water in karst terranes

    SciTech Connect

    Mull, D.S.; Liebermann, T.D.; Smoot, J.L.; Woosley, L.H.

    1988-10-01

    Approximately 20% of the United States is underlain by karst aquifers. This approximation includes roughly 50% of both Kentucky and Tennessee, substantial portions of northern Georgia and Alabama, and parts of other Region IV states. The prevalence of karst aquifers in the southeast, the common use of karst aquifers as drinking water sources and the vulnerability of these aquifers to contamination highlighted the need to provide a mechanism to assist in ground-water management and protection in karst terranes. In an attempt to meet this need, the U.S. Environmental Protection Agency (EPA)--Region IV and the Kentucky District of the U.S. Geological Survey (USGS), have been cooperating to document the application of dye tracing techniques and concepts to ground-water protection in karst aquifers. These efforts have resulted in the preparation of the manual. The information presented herein should be viewed as another analytical 'tool' to assist in the management and protection of karst water supplies.

  13. Assessing the vulnerability of a karst groundwater system to contamination by pharmaceuticals

    NASA Astrophysics Data System (ADS)

    Einsiedl, Florian; Radke, Michael

    2010-05-01

    Contamination of drinking water supplies is a serious problem and a potential threat to public health. Organic micropollutants such as pharmaceuticals and personal care products are identified as an environmental risk and concern has been raised about their environmental presence and fate. These compounds are present in effluents of wastewater treatment plants (WWTPs) in concentrations of up to several µg/L, and they have frequently been detected in surface waters and groundwater systems. A popular method for wastewater disposal in karst areas is the injection of wastewater into open sinkholes. Subsequently, the wastewater infiltrates rapidly along conduits and through the fractured karst aquifer. This is a major contributing factor to the contamination of karst aquifers. To address the vulnerability of such systems against relatively mobile organic micropollutants, we investigated the occurrence of two pharmaceuticals (diclofenac, ibuprofen) in combination with the groundwater heterogeneity and flow pathways in the aquifer. Groundwater samples and effluents of three WWTPs were repeatedly collected during a field campaign in the Franconian Alb karst system which is located in southern Germany. These results were coupled with hydrogeological investigations such as tracer tests, application of environmental isotopes (3H), and modeling. The results of this study demonstrated that (i) both pharmaceuticals are mobile in the karst aquifer and thus represent a risk for contamination of karst water, (ii) the transport of pharmaceuticals in the fractured system with mean transit times of some years affects the karst groundwater contamination, and (iii) long-term wastewater injection containing organic micropollutants into karst ecosystems may contribute to water quality deterioration over years.

  14. Pesticides and biocides in a karst catchment: Identification of contaminant sources and related flow components

    NASA Astrophysics Data System (ADS)

    Wagner, Thomas; Bollmann, Ulla E.; Bester, Kai; Birk, Steffen

    2013-04-01

    Karst aquifers are widely used as drinking water resources. However, their high vulnerability to chemical and bacterial contamination due to the heterogeneity in aquifer properties (highly conductive solution conduits embedded in the less conductive fissured rock) is difficult to assess and thus poses major challenges to the management of karst water resources. Contamination of karst springs by organic micro-pollutants has been observed in recent studies. Within this study the water from different springs draining one karst aquifer as well as the main sinking stream replenishing it were analysed before, during and after a storm water event in order to examine the occurrence of different pesticides and biocides. Contaminants from both urban as well as agricultural origin could be detected in the water with concentrations in the low ng/L range (tebuconazole, carbendazim, diuron, isoproturon, terbutryn, atrazine, dichlorobenzamide (BAM), which is a metabolite of dichlobenil). While some compounds could be followed from the sinking stream to the springs (e.g. dichlorobenzamide) some seem to have a source in the autogenic recharge from the karst plateau (Tebuconazole: wood preservative in buildings). These compounds appear to be related to fast flow components with residence times in the order of days, which are known from a number of tracer tests with fluorescent dyes. However, the occurrence of the pesticide atrazine (banned since 1995 in Austria) in the springs, while on the other hand no current input into the karst occurs, shows that some compounds have long residence times in the karst aquifer. These differences in residence times can hardly be attributed to differences in physico-chemical properties of the compounds and must thus be due to the presence of slow and fast flow components. This is in agreement with the duality of karst aquifers due to highly conductive networks of solution conduits embedded in less conductive fissured carbonate rocks.

  15. Revison of an Atheloptic Visean Trilobite Association in the Moravian Karst (Czech Republic)

    NASA Astrophysics Data System (ADS)

    Rak, Štěpán; Viktorýn, Tomáš; Otava, JiŘí

    2015-01-01

    Recently two new trilobite occurrences were discovered during geological mapping of fossiliferous shales of the Březina Formation around the village of Březina in the Moravian Karst (Czech Republic). The newly discovered localities are extraordinary because of the unexpected occurrence of articulated trilobite exoskeletons associated with brachiopods including supporting spines. The new atheloptic association of Mississippian trilobites is described for the first time from the Moravian Karst.

  16. Influence of karst evolution on solute transport evaluated by process-based numerical modelling

    NASA Astrophysics Data System (ADS)

    Hubinger, Bernhard; Birk, Steffen

    2010-05-01

    Karst waters are of major interest in water resources management. Because of their inherent properties karst systems show great vulnerability with regard to contaminants. Karst systems include highly permeable solution conduit networks formed by chemical aggressive water embedded in a fissured matrix. Small initial voids are widened and thus act as preferential passages, where flow is rapid and often turbulent. Water discharging at karst spring originates from different pathways with different residence times. Contaminant transport through conduit pathways is very rapid, whereas flow through the fissured porous matrix is much slower. Thus, on the one hand, pollutants may be rapidly transported and reach high concentrations at the karst spring shortly after their release; on the other hand, the existence of slow flow components may cause the pollution to last for long times. In this work, solute transport properties of karst aquifers are investigated using generic conduit networks of hydraulically connected proto-conduits with initially log-normally distributed apertures in the millimetre range and below. Conduit evolution is modelled by coupling flow, transport, and dissolution processes, whereby single conduits are widened up to the metre range. Thus, different stages of karst evolution can be distinguished. The resulting flow systems provide the basis for modelling advective-dispersive transport of non-reactive solutes through the network of more or less widened (proto-)conduits. The general transport characteristics in karst systems as well as the influence of heterogeneities and structures on solute transport are illustrated for cases of direct injection into the conduit systems at different evolutionary stages. The resulting breakthrough curves typically show several distinct, chronologically shifted peaks with long tailings, which appears to be similar to data from field tracer experiments.

  17. Characterization of a binary karst aquifer using process time scales

    NASA Astrophysics Data System (ADS)

    Birk, Steffen; Wagner, Thomas

    2013-04-01

    Within "a theoretical framework for the interpretation of karst spring signals" (Covington, EGU2012-853-1) process length scales that characterize the travel distances required for damping pulses of physicochemical parameters of spring waters such as electrical conductivity and temperature were derived (Covington et al., J. Geophys. Res., 2012). These length scales can be converted to corresponding process time scales characterizing the travel times needed for damping the pulses. This is particularly convenient if the travel distance is unknown. In this case the time lag between the increase of spring discharge and subsequent physicochemical responses at the spring may provide an estimate of the travel time. In binary karst aquifers with localized recharge from a sinking stream, the recharge pulse can be directly observed and thus travel times are readily obtained from the time delay of the physicochemical spring responses. If the spring response is strongly damped travel times can be inferred from artificial tracer testing. In this work, time scales for carbonate dissolution and heat transport were used for characterizing the binary Lurbach-Tanneben karst aquifer (Austria). This aquifer receives allogenic recharge from the sinking stream Lurbach and is drained by two springs, namely the Hammerbach and the Schmelzbach. The two springs show different thermal responses to two recharge events in December 2008: Whereas the temperature of the Schmelzbach responds within one day after the flood pulse in the Lurbach, the temperature signal is strongly damped at the Hammerbach. The evaluation based on the thermal time scale thus suggests that the Schmelzbach spring is fed by conduits with hydraulic diameters at least in the order of decimetres. In contrast, the damping of the thermal responses at the Hammerbach may be due to lower hydraulic diameters and/or longer residence times. Interestingly, the Hammerbach did show thermal responses in the time before a flood event in

  18. Morphometric analysis of sinkholes in a karst coastal area

    NASA Astrophysics Data System (ADS)

    Basso, A.; Bruno, E.; Parise, M.; Pepe, M.

    2012-04-01

    Salento, the southern portion of Apulia region (SE Italy) is a narrow and elongated peninsula in carbonate rocks, with prevailing low coastlines, locally interrupted by high rock cliffs. The long stretches of low coasts are marked by typical karst landforms consisting of collapse sinkholes. These are locally designated with the dialectal term "spunnulate" (deriving from the verb "spunnare", which means to break, to sink; PARISE et al., 2003). As observed in many other karst coastal settings worldwide (FORTH et al., 1999), development of sinkholes may be particularly severe along the coast, where both natural and anthropogenic processes contribute to accelerate the dissolution of carbonate rocks and subsidence processes, influencing the coastline evolution. Following a previous study, where the main features of sinkholes at Torre Castiglione (Taranto province) were investigated and described, and a preliminary susceptibility map produced (BRUNO et al., 2008), in the present paper we perform a detailed morphometric analysis on the sample of identified sinkholes. The main morphometric parameters generally used for sinkhole characterization have been considered in this study: shape of the sinkhole, azimuth and length of major and minimum axes, depth, elongation ratio, distance from the shorelines. Each of them is described, both as individual parameter and in conjunction with the others, in the attempt to identify the main factors controlling development of sinkholes in the area, and their evolution as well. As regards this latter aspect, beside simple morphometry of the sample of sinkholes at Torre Castiglione, we also focused our attention on the likely relationships existing between distribution and shape of the sinkholes and the tectonic discontinuities. The role played by discontinuities in controlling both distribution and evolution of sinkholes has been pointed out by several authors (WHITE & WHITE, 1987; DENIZMAN, 2003; FLOREA, 2005). To investigate the matter

  19. Effects of precipitation events on colloids in a karst aquifer

    NASA Astrophysics Data System (ADS)

    Shevenell, Lisa; McCarthy, John F.

    2002-01-01

    The effects of precipitation events on colloid mobilization were evaluated during several storms from six wells in a karstic aquifer at the Oak Ridge Y-12 Plant in eastern Tennessee (USA). Turbidity increases and rapidly recedes following rain events. Although the magnitude of the turbidity increases are relatively small (≤4.78 NTU), the increased turbidity suggests transient increases in colloid abundance during storm versus non-storm periods. During the larger storms (>19 mm), the increased turbidity is associated with increases in pH, total organic carbon (TOC) and temperature, and with decreases in dissolved oxygen (DO). These larger storms result in flushing of a greater proportion of higher pH, TOC (and lower DO) soil or matrix waters into the fractures and conduits than occurs during smaller storms. Smaller storms also result in increases in turbidity, but show increases in DO and decreases in pH reflecting less influence on the water chemistry from the longer residence time epikarst or and matrix waters, and greater impact from the more dilute, newly recharged waters. Due to the complexity of karst flow and temporal variations in flow and chemistry, controls on turbidity are not consistent through time and space at the wells. During smaller storms, recharge by lower ionic strength waters may promote colloid release and thus contribute to observed increases in turbidity. During larger storms, elevated turbidity may be more related to pH increases resulting from greater influx of matrix and soil waters into fractures and conduits. Chemical factors alone cannot account for the changes in turbidity observed during the various storms. Because of the complicated nature of flow and particle transport in karst aquifers, the presence of colloids during precipitation events is dictated by a complex interplay of chemical reactions and the effects of physical perturbations due to increased flow through the conduits and fractures. Simple trends in water quality

  20. Karst medium characterization and simulation of groundwater flow in Lijiang Riversed, China

    NASA Astrophysics Data System (ADS)

    Hu, B. X.

    2015-12-01

    It is important to study water and carbon cycle processes for water resource management, pollution prevention and global warming influence on southwest karst region of China. Lijiang river basin is selected as our study region. Interdisciplinary field and laboratory experiments with various technologies are conducted to characterize the karst aquifers in detail. Key processes in the karst water cycle and carbon cycle are determined. Based on the MODFLOW-CFP model, new watershed flow and carbon cycle models are developed coupled subsurface and surface water flow models, flow and chemical/biological models. Our study is focused on the karst springshed in Mao village. The mechanisms coupling carbon cycle and water cycle are explored. Parallel computing technology is used to construct the numerical model for the carbon cycle and water cycle in the small scale watershed, which are calibrated and verified by field observations. The developed coupling model for the small scale watershed is extended to a large scale watershed considering the scale effect of model parameters and proper model structure simplification. The large scale watershed model is used to study water cycle and carbon cycle in Lijiang rivershed, and to calculate the carbon flux and carbon sinks in the Lijiang river basin. The study results provide scientific methods for water resources management and environmental protection in southwest karst region corresponding to global climate change. This study could provide basic theory and simulation method for geological carbon sequestration in China karst region.

  1. The Soil Biota Composition along a Progressive Succession of Secondary Vegetation in a Karst Area

    PubMed Central

    He, Xunyang; Liu, Lu; Wang, Kelin

    2014-01-01

    Karst ecosystems are fragile and are in many regions degraded by anthropogenic activities. Current management of degraded karst areas focuses on aboveground vegetation succession or recovery and aims at establishing a forest ecosystem. Whether progressive succession of vegetation in karst areas is accompanied by establishment of soil biota is poorly understood. In the present study, soil microbial and nematode communities, as well as soil physico-chemical properties were studied along a progressive succession of secondary vegetation (from grassland to shrubland to forest) in a karst area in southwest China. Microbial biomass, nematode density, ratio of fungal to bacterial biomass, nematode structure index, and nematode enrichment index decreased with the secondary succession in the plant community. Overall, the results indicated a pattern of declines in soil biota abundance and food web complexity that was associated with a decrease in soil pH and a decrease in soil organic carbon content with the progressive secondary succession of the plant community. Our findings suggest that soil biota amendment is necessary during karst ecosystem restoration and establishment and management of grasslands may be feasible in karst areas. PMID:25379741

  2. Karst in the United States: a digital map compilation and database

    USGS Publications Warehouse

    Weary, David J.; Doctor, Daniel H.

    2014-01-01

    This report describes new digital maps delineating areas of the United States, including Puerto Rico and the U.S. Virgin Islands, having karst or the potential for development of karst and pseudokarst. These maps show areas underlain by soluble rocks and also by volcanic rocks, sedimentary deposits, and permafrost that have potential for karst or pseudokarst development. All 50 States contain rocks with potential for karst development, and about 18 percent of their area is underlain by soluble rocks having karst or the potential for development of karst features. The areas of soluble rocks shown are based primarily on selection from State geologic maps of rock units containing significant amounts of carbonate or evaporite minerals. Areas underlain by soluble rocks are further classified by general climate setting, degree of induration, and degree of exposure. Areas having potential for volcanic pseudokarst are those underlain chiefly by basaltic-flow rocks no older than Miocene in age. Areas with potential for pseudokarst features in sedimentary rocks are in relatively unconsolidated rocks from which pseudokarst features, such as piping caves, have been reported. Areas having potential for development of thermokarst features, mapped exclusively in Alaska, contain permafrost in relatively thick surficial deposits containing ground ice. This report includes a GIS database with links from the map unit polygons to online geologic unit descriptions.

  3. Occurrence and transport of pharmaceuticals in a karst groundwater system affected by domestic wastewater treatment plants.

    PubMed

    Einsiedl, Florian; Radke, Michael; Maloszewski, Piotr

    2010-09-20

    The occurrence of two pharmaceuticals, ibuprofen and diclofenac, in a vulnerable karst groundwater system was investigated. The hydrogeology of the karst system was identified by collecting (3)H samples in groundwater over 27years and by performing tracer tests. The isotopes and tracer data were interpreted by mathematical modeling to estimate the mean transit time of water and to characterize the hydrogeological flow paths in the groundwater system. By this approach, a mean (3)H transit time of 4.6 years for the fissured-porous karst aquifer was determined, whereas the fast flowing water in the conduit system showed a mean transit time of days. Both pharmaceuticals which infiltrated along sinkholes and small streams into the karst system were detected in concentrations of up to approximately 1 microg/L in effluent water of the wastewater treatment plants. Diclofenac was present in most samples collected from four springs discharging the karst groundwater to the rivers Altmühl and Anlauter in concentrations between 3.6 and 15.4 ng/L. In contrast, ibuprofen was rarely detected in groundwater. The results of this study suggest that both pharmaceuticals move into the fractured system of the karst system and go into storage. Thus dilution processes are the dominant control on the concentrations of both pharmaceuticals in the fractured system, whereas biodegradation is likely less important.

  4. The soil biota composition along a progressive succession of secondary vegetation in a karst area.

    PubMed

    Zhao, Jie; Li, Shengping; He, Xunyang; Liu, Lu; Wang, Kelin

    2014-01-01

    Karst ecosystems are fragile and are in many regions degraded by anthropogenic activities. Current management of degraded karst areas focuses on aboveground vegetation succession or recovery and aims at establishing a forest ecosystem. Whether progressive succession of vegetation in karst areas is accompanied by establishment of soil biota is poorly understood. In the present study, soil microbial and nematode communities, as well as soil physico-chemical properties were studied along a progressive succession of secondary vegetation (from grassland to shrubland to forest) in a karst area in southwest China. Microbial biomass, nematode density, ratio of fungal to bacterial biomass, nematode structure index, and nematode enrichment index decreased with the secondary succession in the plant community. Overall, the results indicated a pattern of declines in soil biota abundance and food web complexity that was associated with a decrease in soil pH and a decrease in soil organic carbon content with the progressive secondary succession of the plant community. Our findings suggest that soil biota amendment is necessary during karst ecosystem restoration and establishment and management of grasslands may be feasible in karst areas.

  5. Dynamics and anthropogenic impacts of multiple karst flow systems in a mountainous area of South China

    NASA Astrophysics Data System (ADS)

    Luo, Mingming; Chen, Zhihua; Criss, Robert E.; Zhou, Hong; Huang, He; Han, Zhaofeng; Shi, Tingting

    2016-08-01

    The Xiangxi River basin, South China, is a steep terrane with well-developed karst features and an important Cambrian-Ordovician aquifer. Meteoric water in this mountainous area features a mean δ18O elevation gradient of -2.4 ‰/km. This gradient was used to estimate mean recharge elevations of 760 m for Shuimoxi (SMX) spring, 1,060 m for Xiangshuidong (XSD) spring, and 1,430 m for drill hole ZK03, indicating multiple flow paths in the Cambrian-Ordovician karst aquifer. Mean residence times of 230 and 320 days and ˜2 years were estimated for these features, respectively, using the damped running average model that predicts the isotopic variations in groundwater from those in precipitation. Groundwater in the regional karst flow system has the longest residence time, the highest recharge elevation, the longest flow paths, the lowest addition of anthropogenic components, and the greatest amount of water-rock interaction as indicated by its higher dissolved solids, Mg2+ concentrations and Mg/Ca ratios than the springs. In contrast, the local and shallow karst flow systems respond rapidly to recharge events. Artificial tracer tests prove that these shallow karst systems can also quickly transmit anthropogenic contaminants, indicating that they are highly vulnerable to human impacts, which include the enrichment of NO3 -. The intensity of water-rock interaction and groundwater vulnerability are mainly determined by the structure and dynamics of the multiple karst flow systems.

  6. Occurrence and transport of pharmaceuticals in a karst groundwater system affected by domestic wastewater treatment plants

    NASA Astrophysics Data System (ADS)

    Einsiedl, Florian; Radke, Michael; Maloszewski, Piotr

    2010-09-01

    The occurrence of two pharmaceuticals, ibuprofen and diclofenac, in a vulnerable karst groundwater system was investigated. The hydrogeology of the karst system was identified by collecting 3H samples in groundwater over 27 years and by performing tracer tests. The isotopes and tracer data were interpreted by mathematical modeling to estimate the mean transit time of water and to characterize the hydrogeological flow paths in the groundwater system. By this approach, a mean 3H transit time of 4.6 years for the fissured-porous karst aquifer was determined, whereas the fast flowing water in the conduit system showed a mean transit time of days. Both pharmaceuticals which infiltrated along sinkholes and small streams into the karst system were detected in concentrations of up to approximately 1 μg/L in effluent water of the wastewater treatment plants. Diclofenac was present in most samples collected from four springs discharging the karst groundwater to the rivers Altmühl and Anlauter in concentrations between 3.6 and 15.4 ng/L. In contrast, ibuprofen was rarely detected in groundwater. The results of this study suggest that both pharmaceuticals move into the fractured system of the karst system and go into storage. Thus dilution processes are the dominant control on the concentrations of both pharmaceuticals in the fractured system, whereas biodegradation is likely less important.

  7. SWISSKARST Project - how to document the karst aquifers in Switzerland using the KARSYS approach.

    NASA Astrophysics Data System (ADS)

    Malard, A.; Vouillamoz, J.; Jeannin, P.-Y.; Weber, E.; Eichenberger, U.

    2012-04-01

    Swiss karst aquifers are poorly documented although they represent a resource estimated to around 120 km3 of fresh water - which is comparable to the water volume of all Swiss lakes. Within the framework of the Swiss National Research Program 61 an opportunity was given to develop a systematic way to characterize karst aquifers and to describe their hydrological behaviour. The project aims at providing methodologies or guidelines to approach karst systems and to improve their management. This covers a large range of fields such as water supply, civil engineering, renewable energies, natural hazards, etc. In this context SISKA developed a dedicated approach named KARSYS for KARst SYStems characterization. It is based on iterations of 3D geological models combined with some basic hydraulic principles taking place in karst media. The main principles are: (i) The 3D geometry of the aquifer set the framework in which flow processes take place (ii) Aquifers are flooded below the level of the main perennial springs (iii) The expansion of the water table upstream of the main springs is lower than 1% (low water stage). High water gradients are simulated according to the elevation of temporary springs or observations in existing boreholes or caves. The approach explicitly shows through 3D visual that some groundwater bodies may be separated at low water stage and connected at high water. Such 3D views bring often explanations to the interpretation of "strange" or "not repeatable" dye tracer's results. A major input of KARSYS approach is to provide a systematic construction of a conceptual model for all hydrological karst systems. It also considers interactions between adjacent systems, providing new concepts on the delineation of karst systems. KARSYS approach can be applied in a quick and approximate way and improved along in order to reach a precision according to the question to be addressed. Results of KARSYS applications are: (i) The delineation of catchment areas of

  8. Sinkhole Imaging With Multiple Geophysical Methods in Covered Karst Terrain

    NASA Astrophysics Data System (ADS)

    Weiss, M.

    2005-05-01

    A suite of geophysical surveys was run at the Geopark at the University of South Florida campus in Tampa in attempt to determine the degree to which methods could image a collapsed sinkhole with a diameter of ~4m and maximum depth of ~2.5m. Geologically, the Geopark is part of a covered karst terrane, with collapsed sinkholes filled in by overlying unconsolidated sand separated from the weathered limestone beneath by a clayey sand layer. The sinkholes are hydrologically significant as they may serve as sites of concentrated recharge. The methods used during the study include: refraction seismics, resistivity, electromagnetics (TEM and EM), and ground penetrating radar (GPR). Geophysical data are compared against cores. The resistivity, GPR, and seismic refraction profiles yield remarkably consistent images of the clayey sand layer. EM-31 data revealed regional trends in subsurface geology, but could not delineate specific sinkhole features with the desired resolution.

  9. Application of continuum- and hybrid models in karst spring catchments

    NASA Astrophysics Data System (ADS)

    Rehrl, Christoph; Birk, Steffen

    2010-05-01

    Flow in karst aquifers is concentrated along highly permeable solution conduits embedded in the much less permeable fissured system of the surrounding rock. This complex and heterogeneous flow regime can be conceptualized as dual flow systems composed of slow, laminar flow in the fractured porous matrix as opposed to rapid, often turbulent flow in solution conduits. Flow in the fractured porous rock can be treated as a continuous flow field (continuum model), whereas flow in the conduit system is spatially localized and can be modelled by a discrete pipe network model. Hybrid models couple both flow systems and have frequently been employed in basic research, e.g., to simulate and analyse the mechanism of speleogenesis. In many practical applications, however, continuum models are employed. In these models the two flow components are lumped together and the conduits are represented by highly permeable cells (smeared conduit approach). Standard groundwater models imply that conduit flow is represented by a Darcian approach, thus ignoring potential effects of turbulent flow. On this account the USGS has recently released a MODFLOW-2005 Conduit Flow Process (CFP), which makes it possible to account for turbulent flow in the continuum approach (CFP mode 2). Additionally a discrete pipe network model can be coupled to MODFLOW. This hybrid model (CFP mode 1) employs the Darcy-Weisbach equation to represent turbulent flow in the karst conduits. In this work, it is attempted to simulate the discharge hydrographs of a hypothetical karst spring catchment in which conduit systems are embedded in fissured porous rock using both the single-continuum approach (CFP mode 2) and the hybrid model (CFP mode 1). This study shows that the hydraulic response of the spring signal is influenced by the flow conditions in the conduit, i.e. the shape of the spring hydrograph predicted by a model that accounts for turbulent flow differs from that obtained with a laminar flow model. This

  10. Combining hydraulic model, hydrogeomorphological observations and chemical analyses of surface waters to improve knowledge on karst flash floods genesis

    NASA Astrophysics Data System (ADS)

    Raynaud, F.; Borrell-Estupina, V.; Pistre, S.; Van-Exter, S.; Bourgeois, N.; Dezetter, A.; Servat, E.

    2015-06-01

    During a flood event over a karst watershed, the connections between surface and ground waters appear to be complex ones. The karst may attenuate surface floods by absorbing water or contribute to the surface flood by direct contribution of karst waters in the rivers (perennial and overflowing springs) and by diffuse resurgence along the hillslopes. If it is possible to monitor each known outlet of a karst system, the diffuse contribution is yet difficult to assess. Furthermore, all these connections vary over time according to several factors such as the water content of the soil and underground, the rainfall characteristics, the runoff pathways. Therefore, the contribution of each compartment is generally difficult to assess, and flood dynamics are not fully understood. To face these misunderstandings and difficulties, we analysed surface waters during six recent flood events in the Lirou watershed (a karst tributary of the Lez, in South of France). Because of the specific chemical signature of karst waters, chemical analyses can supply information about water pathways and flood dynamics. Then, we used the dilution law to combine chemical results, flow data and field observations to assess the dynamics of the karst component of the flood. To end, we discussed the surface or karst origin of the waters responsible for the apparent runoff coefficient rise during flash karst flood.

  11. U.S. Geological Survey Karst Interest Group: proceedings, St Petersburg, Florida February 13-16, 2001

    USGS Publications Warehouse

    Kuniansky, Eve L.

    2001-01-01

    Karst and similar landscapes are found in a wide range of biogeographic classes. In the U.S. for example, Everglades, Mammoth Cave, and Hawaii Volcanoes National Parks have little in common - except karst or pseudokarst, and a cultural past (even though these are very different). This diversity of geologic settings makes karst difficult to categorize and work with when designing a national program such as the recent NPS-USGS Geo-Indicators effort. A GIS-based approach with multiple datalayers is the only sane way to understand and convey the many relationships, in X, Y, and Z axes, between component ecosystems and cultural resources within karst and pseudokarst landscapes. Obviously, karst and cultural landscapes cross modern political as well as biogeographic boundaries. Here again, three-dimensional data are the foundation for understanding similar to that in anatomy and physiology: structure and function. In understanding where the most vulnerable 'pressure points' exist within karst landscapes, we can target landscape-scale ecosystem management to greatest effect. USGS and the National Cave and Karst research Institute could play an extremely significant role in cave and karst management on a national scale beyond NPS or other agency boundaries via cooperative management of three-dimensional karst datasets analogous to programs in several states.

  12. U.S. Geological Survey Karst Interest Group Proceedings, Bowling Green, Kentucky, May 27-29, 2008

    USGS Publications Warehouse

    Kuniansky, Eve L.

    2008-01-01

    *INTRODUCTION AND ACKNOWLEDGMENTS* Karst aquifer systems are present throughout parts of the United States and some of its territories. The complex depositional environments that form carbonate rocks combined with post-depositional tectonic events and the diverse climatic regimes under which these rocks were formed result in unique hydrologic systems. The dissolution of calcium carbonate and the subsequent development of distinct and beautiful landscapes, caverns, and springs have resulted in some karst areas of the United States being designated as national or state parks and commercial caverns. Karst aquifers and landscapes that form in tropical areas, such as the north coast of Puerto Rico, differ greatly from karst areas in more arid climates, such as central Texas or western South Dakota. Many of these public and private lands contain unique flora and fauna associated with the hydrologic systems in these karst areas. As a result, multiple Federal, State, and local agencies have an interest in the study of karst terrains. Carbonate sediments and rocks (limestone and dolomite) are composed of greater than 50 percent carbonate minerals and the predominant carbonate mineral is calcium carbonate or limestone (CaCO3). Unlike terrigenous clastic sedimentation, the depositional processes that produce carbonate rocks are complex, involving both biological and physical processes. These depositional processes impact greatly the development of permeability of the sediments. Carbonate minerals readily dissolve or precipitate depending on the chemistry of the water flowing through the rock, thus the study of both marine and meteoric diagenesis of carbonate sediments is multidisciplinary. Even with a better understanding of the depositional environment and subsequent diagenesis, the dual porosity nature of karst aquifers presents challenges to scientists attempting to study ground-water flow and contaminant transport. Many of the major springs and aquifers in the United

  13. Diurnal hydrochemical variations in a karst spring and two ponds, Maolan Karst Experimental Site, China: Biological pump effects

    NASA Astrophysics Data System (ADS)

    Liu, Huan; Liu, Zaihua; Macpherson, G. L.; Yang, Rui; Chen, Bo; Sun, Hailong

    2015-03-01

    A karst spring and two downstream ponds fed by the spring at the Maolan Karst Experimental Site, Guizhou Province, China, were used to investigate the effect of submerged plants on the CO2-H2O-CaCO3 system during a time of spring base flow in summer when underwater photosynthesis was strongest. Temperature, pH, electrical conductivity (EC) and dissolved oxygen (DO) were recorded at 15 min intervals for a period of 30 h (12:00 29 August-18:00 30 August, 2012). [Ca2+], [HCO3-], CO2 partial pressure (pCO2) and saturation index of calcite (SIC) were estimated from the high-frequency measurements. Water samples were also collected three times a day (early morning, midday and evening) for δ13CDIC determination. A floating CO2-flux monitoring chamber was used to measure CO2 flux at the three locations. Results show that there was little or no diurnal variation in the spring water parameters. In the midstream pond with flourishing submerged plants, however, all parameters show distinct diurnal changes: temperature, pH, DO, SIc, δ13CDIC increased during the day and decreased at night, while EC, [HCO3-], [Ca2+], and pCO2 behaved in the opposite sense. In addition, maximum DO values (16-23 mg/L) in the midstream pond at daytime were two to three times those of water equilibrated with atmospheric O2, indicating strong aquatic photosynthesis. The proposed photosynthesis is corroborated by the low calculated pCO2 of 20-200 ppmv, which is much less than atmospheric pCO2. In the downstream pond with fewer submerged plants but larger volume, all parameters displayed similar trends to the midstream pond but with much less change, a pattern that we attribute to the lower biomass/water volume ratio. The diurnal hydrobiogeochemical variations in the two ponds depended essentially on illumination, indicating that photosynthesis and respiration by the submerged plants are the dominant controlling processes. The large loss of DIC between the spring and midstream pond, attributed to

  14. Hazards in the coastal karst of Balai (NW Sardinia, Italy)

    NASA Astrophysics Data System (ADS)

    Sanna, Laura; Uda, Michele; Pascucci, Vincenzo

    2016-04-01

    The coastal karst area of Balai headland is located in the central part of the Gulf of Asinara (North-West Sardinia, Italy) near the city of Porto Torres, comprised between the homonymous harbour and Platamona beach. This karst plateau has a monocline geometry truncated by the coastal escarpment, up to 40 m-high, that in the last decades has been affected by slope instability related to human activities and/or climate change. The area is characterised by a flat morphology constituted of Miocene limestone gently dipping towards the North-West. Its altitude ranges from 0 to 50 m asl. The 3 km-long cliff is locally interrupted by some small gravelly coves. Along the longitudinal profile of the headland, three main morphological steps have been identified at 15, 8 and 6.5 m asl. They represent past wave cut platforms. The shoreline is well marked and the coves cut into the land up to 50 m in length, perpendicularly to the coast. They follow the direction of a series of parallel NE-facing fractures. The modern tidal notch is well exposed along the carbonate cliff at the present sea level. Along the limestone cliff, notch development is amplified by mixing of sea and fresh water coming from submerged springs. Moreover, this marine erosion feature is a good sea level marker in microtidal conditions, such as Mediterranean Sea, and an indicator of tectonic stability, of the Sardinian microplate. In some coves, two generations of fossil notches have been observed at 6.5 m asl and -1 m bsl, respectively, along with lithophaga boreholes up to 8 m asl. Both indicate the past eustatic conditions. All these geomorphic features make Balai promontory an interesting geological spot for studying past sea level fluctuations and present slope movements, trying to distinguish hazards due to climate change from those directly related to anthropogenic forces such as wave-induced damage due to waterborne navigation.

  15. Karst aquifer dynamic modelling by evolutionary polynomial regression

    NASA Astrophysics Data System (ADS)

    Doglioni, Angelo; Giustolisi, Orazio; Simeone, Vincenzo

    2010-05-01

    Evolutionary Polynomial Regression (EPR) is an evolutionary modelling technique which has been successfully applied to multiple problems related to environmental engineering. In particular, it proved quite effective at modelling the dynamic relationship between groundwater levels and rainfall heights for a specific case study related to a porous aquifer. This paper introduces an application of EPR aimed at modelling the relationship between rainfall heights and groundwater tables of a karst aquifer. From a hydrogeological point of view, a karst aquifer is characterized by a quick response to rainfall due to the preferential paths through the ground. It has been monitored over the years thus producing a reasonably long dataset covering about 44 years. On the one hand, these data show some discontinuities, but on the other hand, they are available from a well located in a neighbourhood where there is almost no pumping as well as further disturbances related to human activities. The use of multiobjective EPR will allow finding a set of feasible symbolic models which helps to make a robust choice of models as well as to investigate about the structures of the models and how the aquifer response is influenced by rainfall. The authors makes also a comparison with the results they found for the porous aquifer, thus trying to assess which differences exist, from the physical point of view, between the two cases study and the capability of EPR at catching a quicker dynamics. Finally, it is noteworthy that the investigated aquifer is relatively geographically close to the already investigated one, about 40 km. This will also allow for investigating the effect of rainfall change, in terms of intensity variations, on differently structured aquifers whereas there is a similar climate regime.

  16. Kinetic controls on early karst aquifer porosity development

    SciTech Connect

    Groves, C.G. ); Howard, A.D. . Dept. of Environmental Sciences)

    1992-01-01

    A series of simulations using the newly developed model KARST has been performed to investigate limiting kinetic controls on limestone dissolution during the earliest stages of karst aquifer porosity development. This FORTRAN model couples fluid flow within and dissolution of circular cross section conduits, and considers surface reaction rates (both far from and close to thermodynamic equilibrium), mass transfer rates of reaction products to the bulk fluid, and rates of homogeneous reactions associated with dissolution of CO[sub 2] gas in water. Mass transfer theory for both laminar and turbulent flow cases is included. Runs were made with a wide variety of initial conditions of passage geometry, head gradient, and initial PCO[sub 2]. Results show a consistent pattern of kinetic control that varies as functions of time as well as position along the conduit. Slow, higher order surface reaction rates (close to equilibrium), diffusion rates, and rapid, lower order reaction rates (far from equilibrium) are found to be limiting steps at various times and location. Under no conditions in the simulations did the rate of CO[sub 2] hydration limit dissolution. Thresholds between the various kinetic regimes were found to be associated with a critical distance from equilibrium, as well as the transition from laminar to turbulent flow. As a result of interactions between flow and chemical conditions, passage growth (measure by fluid discharge rates) can be divided into an initial, slow period initiation and a more rapid one (enlargement). The onset of the enlargement phase was not found to coincide with any single kinetic event.

  17. Using nitrate to quantify quick flow in a karst aquifer

    USGS Publications Warehouse

    Mahler, B.J.; Garner, B.D.

    2009-01-01

    In karst aquifers, contaminated recharge can degrade spring water quality, but quantifying the rapid recharge (quick flow) component of spring flow is challenging because of its temporal variability. Here, we investigate the use of nitrate in a two-endmember mixing model to quantify quick flow in Barton Springs, Austin, Texas. Historical nitrate data from recharging creeks and Barton Springs were evaluated to determine a representative nitrate concentration for the aquifer water endmember (1.5 mg/L) and the quick flow endmember (0.17 mg/L for nonstormflow conditions and 0.25 mg/L for stormflow conditions). Under nonstormflow conditions for 1990 to 2005, model results indicated that quick flow contributed from 0% to 55% of spring flow. The nitrate-based two-endmember model was applied to the response of Barton Springs to a storm and results compared to those produced using the same model with ??18O and specific conductance (SC) as tracers. Additionally, the mixing model was modified to allow endmember quick flow values to vary over time. Of the three tracers, nitrate appears to be the most advantageous because it is conservative and because the difference between the concentrations in the two endmembers is large relative to their variance. The ??18O- based model was very sensitive to variability within the quick flow endmember, and SC was not conservative over the timescale of the storm response. We conclude that a nitrate-based two-endmember mixing model might provide a useful approach for quantifying the temporally variable quick flow component of spring flow in some karst systems. ?? 2008 National Ground Water Association.

  18. Biodegradation of chlorinated ethenes at a karst site in middle Tennessee

    USGS Publications Warehouse

    Byl, Thomas Duane; Williams, Shannon D.

    2000-01-01

    This report presents results of field and laboratory investigations examining the biodegradation of chlorinated ethenes in a karst aquifer contaminated with trichloroethylene (TCE). The study site, located in Middle Tennessee, was selected because of the presence of TCE degradation byproducts in the karst aquifer and available site hydrologic and chlorinated-ethene information. Additional chemical, biological, and hydrologic data were gathered to evaluate whether the occurrence of TCE degradation byproducts in the karst aquifer was the result of biodegradation within the aquifer or simply transport into the aquifer. Geochemical analysis established that sulfate-reducing conditions, essential for reductive dechlorination of chlorinated solvents, existed in parts of the contaminated karst aquifer. Other areas of the aquifer fluctuated between anaerobic and aerobic conditions and contained compounds associated with cometabolism, such as ethane, methane, ammonia, and dissolved oxygen. A large, diverse bacteria population inhabits the contaminated aquifer. Bacteria known to biodegrade TCE and other chlorinated solvents, such as sulfate-reducers, methanotrophs, and ammonia-oxidizers, were identified from karst-aquifer water using the RNA-hybridization technique. Results from microcosms using raw karst-aquifer water found that aerobic cometabolism and anaerobic reductive-dechlorination degradation processes were possible when appropriate conditions were established in the microcosms. These chemical and biological results provide circumstantial evidence that several biodegradation processes are active in the aquifer. Additional site hydrologic information was developed to determine if appropriate conditions persist long enough in the karst aquifer for these biodegradation processes to be significant. Continuous monitoring devices placed in four wells during the spring of 1998 indicated that pH, specific conductance, dissolved oxygen, and oxidation-reduction potentials

  19. Karst development in the Tobosa basin (Ordovician-Devonian) strata in the El Paso border region of west Texas

    SciTech Connect

    Lemone, D.V. . Dept. of Geological Sciences)

    1993-02-01

    Karst development within the Tobosa basin strata in the El Paso border region is best displayed during two time intervals: Middle Ordovician (27 Ma) developed on the Lower Ordovician El Paso Group and Middle Silurian to Middle Devonian (40 Ma) karst developed on the Lower-Middle Fusselman Formation. These major exposure intervals are recognized in regional outcrops as well as in the subsurface of the Permian Basin where they form major reservoirs. Minor local karsting is noted also within and upon the Upper Ordovician (Montoya Group) and within the shoaling upward members of overlying the Fusselman Formation. Middle Ordovician karsting with major cavern development extends down into McKellingon Canyon Formation approximately 1,000 feet below the top of the Lower Ordovician El Paso Group. The McKellingon is overlain by the cavern roof-forming early diagenetic dolomites, lower Scenic Drive Formation which in turn is overlain by the locally karsted upper Scenic Drive and Florida Mountains formations. Collapse of the overlying Montoya Group into El Paso Group rocks is observed. The Fusselman Formation rests disconformably on the Montoya Group. It is a massive, vuggy, fine- to coarsely-crystalline, whitish dolomite. Extensive karsting has developed on the top of the Fusselman. The middle Devonian Canutillo Formation with a basal flooding deposit overlies this karst surface. Minor karsting following fracture systems extends from the major karst of the El Paso Group up into the major karst in the Fusselman. The karst seems to be following and developing along the same linear fracture systems. If so, it is not unreasonable to interpret these fracture systems as being inherited from the earlier Precambrian structures underlying them.

  20. An examination of the factors governing the development of karst topography in the Cumberland Valley of Pennsylvania

    SciTech Connect

    Ackerman, R.V. . Dept. of Geological Sciences)

    1993-03-01

    The landscape of the Cumberland Valley of South Central Pennsylvania is dominated by karst topography. A study was initiated to determine if the development of karst was controlled primarily by geologic structure or by lithologic differences. Existing data concerning the geographic locations of karst features, the hydrogeologic characteristics of the Cumberland Valley, and the chemistry of the eleven carbonate formations within the 518 km[sup 2] study area were compiled. Data concerning 366 mapped sinkholes and over 9,000 additional karst features and their relations to the structural, lithological and spatial characteristics of the study area were collected and compiled into the database. Other factors contributing to karst development such as groundwater flow, soil and colluvium characteristics, and geographic distribution were considered. The data suggest that structure dominates lithology in the development of karst features within the study area. Structural features such as fractures, joints and folds, which create secondary porosity, are prerequisite for solution of the carbonate bedrock. Joint systems, fold axes, igneous intrusions, caves, springs and groundwater flow have a significant impact on the development of karst features. The presence of faults proved inconclusive. There are a greater number of karst features per unit area in areas of purer limestones (units with a lower percentage of acid insoluble residue). Lithological variations impact karst development only when structural features are present to provide secondary porosity that enhances chemical weathering. The distribution of karst features and the geologic factors governing their development and distribution should be taken into account when land-use decisions in karst terrains are made.

  1. Advances in Dynamic Transport of Organic Contaminants in Karst Groundwater Systems

    NASA Astrophysics Data System (ADS)

    Padilla, I. Y.; Vesper, D.; Alshawabkeh, A.; Hellweger, F.

    2011-12-01

    Karst groundwater systems develop in soluble rocks such as limestone, and are characterized by high permeability and well-developed conduit porosity. These systems provide important freshwater resources for human consumption and ecological integrity of streams, wetlands, and coastal zones. The same characteristics that make karst aquifers highly productive make them highly vulnerable to contamination. As a result, karst aquifers serve as an important route for contaminants exposure to humans and wildlife. Transport of organic contaminants in karst ground-water occurs in complex pathways influenced by the flow mechanism predominating in the aquifer: conduit-flow dominated systems tend to convey solutes rapidly through the system to a discharge point without much attenuation; diffuse-flow systems, on the other hand, can cause significant solute retardation and slow movement. These two mechanisms represent end members of a wide spectrum of conditions found in karst areas, and often a combination of conduit- and diffuse-flow mechanisms is encountered, where both flow mechanisms can control the fate and transport of contaminants. This is the case in the carbonate aquifers of northern Puerto Rico. This work addresses advances made on the characterization of fate and transport processes in karst ground-water systems characterized by variable conduit and/or diffusion dominated flow under high- and low-flow conditions. It involves laboratory-scale physical modeling and field-scale sampling and historical analysis of contaminant distribution. Statistical analysis of solute transport in Geo-Hydrobed physical models shows the heterogeneous character of transport dynamics in karstic units, and its variability under different flow regimes. Field-work analysis of chlorinated volatile organic compounds and phthalates indicates a large capacity of the karst systems to store and transmit contaminants. This work is part of the program "Puerto Rico Testsite for Exploring Contamination

  2. Estimating annual effective infiltration coefficient and groundwater recharge for karst aquifers of the southern Apennines

    NASA Astrophysics Data System (ADS)

    Allocca, V.; Manna, F.; De Vita, P.

    2013-08-01

    To assess the mean annual groundwater recharge of the karst aquifers in southern Apennines (Italy), the estimation of the mean annual effective infiltration coefficient (AEIC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. We studied a large part of the southern Apennines that is covered by a meteorological network and containing 40 principal karst aquifers. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926-2012, the annual effective precipitation (AEP) was estimated, and its distribution was modelled, by considering the orographic barrier and rain shadow effects of the Apennines chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AEIC by means of the hydrological budget equation. The resulting AEIC values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst-rock, morphological settings, land use and covering soil type. A simple correlation relationship between AEIC, lithology and the summit flat and endorheic areas was found. This empirical model has been used to estimate AEIC and mean annual groundwater recharge in other regional karst aquifers. The estimated AEIC values ranged between 48% and 78%, thus matching intervals estimated for other karst aquifers in European and Mediterranean countries. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterisations are also perceived as useful for the assessment of mean annual runoff over carbonate mountains, which is another important

  3. Organic carbon storage in four ecosystem types in the karst region of southwestern China.

    PubMed

    Liu, Yuguo; Liu, Changcheng; Wang, Shijie; Guo, Ke; Yang, Jun; Zhang, Xinshi; Li, Guoqing

    2013-01-01

    Karst ecosystems are important landscape types that cover about 12% of the world's land area. The role of karst ecosystems in the global carbon cycle remains unclear, due to the lack of an appropriate method for determining the thickness of the solum, a representative sampling of the soil and data of organic carbon stocks at the ecosystem level. The karst region in southwestern China is the largest in the world. In this study, we estimated biomass, soil quantity and ecosystem organic carbon stocks in four vegetation types typical of karst ecosystems in this region, shrub grasslands (SG), thorn shrubbery (TS), forest - shrub transition (FS) and secondary forest (F). The results showed that the biomass of SG, TS, FS, and F is 0.52, 0.85, 5.9 and 19.2 kg m(-2), respectively and the corresponding organic cabon storage is 0.26, 0.40, 2.83 and 9.09 kg m(-2), respectively. Nevertheless, soil quantity and corresponding organic carbon storage are very small in karst habitats. The quantity of fine earth overlaying the physical weathering zone of the carbonate rock of SG, TS, FS and F is 38.10, 99.24, 29.57 and 61.89 kg m(-2), respectively, while the corresponding organic carbon storage is only 3.34, 4.10, 2.37, 5.25 kg m(-2), respectively. As a whole, ecosystem organic carbon storage of SG, TS, FS, and F is 3.81, 4.72, 5.68 and 15.1 kg m(-2), respectively. These are very low levels compared to other ecosystems in non-karst areas. With the restoration of degraded vegetation, karst ecosystems in southwestern China may play active roles in mitigating the increasing CO2 concentration in the atmosphere.

  4. Studying the flow dynamics of a karst aquifer system with an equivalent porous medium model.

    PubMed

    Abusaada, Muath; Sauter, Martin

    2013-01-01

    The modeling of groundwater flow in karst aquifers is a challenge due to the extreme heterogeneity of its hydraulic parameters and the duality in their discharge behavior, that is, rapid response of highly conductive karst conduits and delayed drainage of the low-permeability fractured matrix after recharge events. There are a number of different modeling approaches for the simulation of the karst groundwater dynamics, applicable to different aquifer as well as modeling problem types, ranging from continuum models to double continuum models to discrete and hybrid models. This study presents the application of an equivalent porous model approach (EPM, single continuum model) to construct a steady-state numerical flow model for an important karst aquifer, that is, the Western Mountain Aquifer Basin (WMAB), shared by Israel and the West-Bank, using MODFLOW2000. The WMAB was used as a catchment since it is a well-constrained catchment with well-defined recharge and discharge components and therefore allows a control on the modeling approach, a very rare opportunity for karst aquifer modeling. The model demonstrates the applicability of equivalent porous medium models for the simulation of karst systems, despite their large contrast in hydraulic conductivities. As long as the simulated saturated volume is large enough to average out the local influence of karst conduits and as long as transport velocities are not an issue, EPM models excellently simulate the observed head distribution. The model serves as a starting basis that will be used as a reference for developing a long-term dynamic model for the WMAB, starting from the pre-development period (i.e., 1940s) up to date.

  5. Variations of the spatiotemporal patterns of CVOCs concentrations in northern karst of Puerto Rico

    NASA Astrophysics Data System (ADS)

    Yu, X.; Ghasemizadeh, R.; Padilla, I. Y.; Irizarry, C.; Yegen, C.; Kaeli, D.; Alshawabkeh, A. N.

    2013-12-01

    The northern Puerto Rico is characterized as karst topography, where the groundwater is a major source of water use to the island. Various types of Chlorinated Volatile Organic Compounds (CVOCs), which are due to improper disposal of industrial waste, are detected in these karst aquifers. It is important to study the spatiotemporal distribution patterns of the CVOCs in this region, which are posing a serious threat to both the ecological and human health. In this study, various historical CVOCs data from 264 wells across the northern karst region from January 1982 to December 2000 were collected from a number of reports and studies. We found that 38% (99 out of 264) of the sites had at least one sample with CVOC concentration above the standards established to protect human health over the study period. We found that the distribution of the CVOCs spatially varied with areas containing clusters of sites contaminated by different organic compound. The response of CVOC concentrations were occasionally retarded even though they were depleted significantly in the source zones. The study confirmed that the measured CVOC concentrations decreased during the study period at most of the sites. The source origin (toxics release locations and quantities) and the intrinsic characteristics of the karst (high heterogeneity and complex hydraulic behavior) are most likely related with the spatial and temporal distribution patterns of CVOCs. The study of the spatiotemporal patterns of CVOCs concentrations in the northern karst aquifers has important implications on the public water use, especially when it coincides with the recent population growth in this region. Locations of Puerto Rico, the northern karst region of Puerto Rico and 264 sampling sites in the karst region.

  6. Natural and Artificial (fluorescent) Tracers to Characterise Hydrogeological Functioning and to Protect Karst Aquifers

    NASA Astrophysics Data System (ADS)

    Andreo, B.; Mudarra, M.; Marin, A. I.; Barberá, J. A.

    2012-12-01

    The hydrogeological functioning and response of karst aquifers can be determined by the joint use of natural hydrogeochemical tracers, especially total organic carbon (TOC) and intrinsic fluorescence of water, together with artificial (fluorescent) tracers, under the same hydrodynamic conditions. Sharp and rapid variations in discharge, temperature, electrical conductivity and water chemistry, particularly of natural tracers of infiltration (TOC, intrinsic fluorescence and NO3-) recorded in karst spring water, confirm the existence of well developed karst conduits in the sector of the aquifer being drained, with rapid flows and very short water transit times from the surface to the springs (Mudarra et al., 2011). This is in agreement with the evidence obtained from breakthrough curves of fluorescent dye tracers (uranine, eosine, etc.). However, time lags between maximum concentrations of natural (especially TOC and intrinsic fluorescence) and artificial tracers show that the global system response is faster than that produced from a recharge concentrated at a point on the surface, even in karst sinkholes. Response and transit times of water through the karst can be calculated using both natural and artificial tracers, but flow velocities can really only be quantified using artificial tracers. Analysis of the responses obtained by natural tracers of infiltration (global system response) and artificial tracers (single response) in karst waters has revealed the usefulness and complementarity of both techniques for characterising the hydrogeological functioning of karst aquifers and, even more important, for validating contamination vulnerability mapping in these medium (Zwahlen, 2004; Andreo et al., 2006). In recent decades, several methods have been developed for such vulnerability mapping, but little progress has been made in validating their results. This validation is essential for the adequate protection of water resources in karst media, as has been shown in

  7. Carbonate speleothems from western Mediterranean gypsum karst: palaeoclimate implications

    NASA Astrophysics Data System (ADS)

    Columbu, Andrea; Drysdale, Russell; Woodhead, Jon; Chiarini, Veronica; De Waele, Jo; Hellstrom, John; Forti, Paolo; Sanna, Laura

    2016-04-01

    Gypsum caves are uncommon environments for carbonate speleothems (cave deposits). Contrary to limestone caves, the only source of non-atmospheric carbon is from biogenic CO2 produced by the overlying soils. Enhanced CO2 content in soils is in turn related with climate, where warm temperatures and high humidity favour plant activity .().....(Fairchild and Baker, 2012). Although poorly decorated, the exploration of northern Italian and Spanish gypsum karst systems reveals the existence of several generations of carbonate speleothems, which have been dated with the U-Th series method .()......(Hellstrom, 2003; Scholz and Hoffmann, 2008). Their ages coincide with current and previous two interglacials (MIS 1, 5e and 7e and Greenland interstadials (GIS) 19, 20, 21 and 24. Considering that these periods are amongst the most pronounced warm-wet pulsations over the last 250,000 ...(Martrat et al., 2007; NGRIP, 2004), and that CO2 has a fundamental role in this karst process, this study explores the climate-driven hydrogeological conditions necessary to trigger carbonate deposition in gypsum voids. The further correlation with sapropel events 5, 4, 3 and 1, considered symptomatic of enhanced rainfall across the whole Mediterranean basin .(.)(Emeis et al., 1991), highlights the importance of flow-rate in the fracture network and infiltration of meteoric water into the caves. The combination of high CO2 and a phreatic status of the fracture network is thus indispensable for the formation of carbonate speleothems in gypsum karst. This condition appears to be triggered by periods of orbital precession minimum, when the monsoonal activity peaked in the Atlantic area. Stable oxygen isotope signatures suggest that the speleothems did not grow during any interglacial-glacial or main interstadial-stadial transitions, confirming that variations from optimum climate conditions may hamper the formation of this category of speleothems. New speleological exploration and sampling campaign

  8. Process studies of water percolation in a Mediterranean karst area

    NASA Astrophysics Data System (ADS)

    Lange, J.; Arbel, Y.; Greenbaum, N.; Grodek, T.

    2009-04-01

    In drylands karst environments comprise large areas and their groundwater resources are important for local and regional water supply. Recharge estimations are usually based on long term averages and hence uncertain, because they do not explicitly account for the accentuated variability of dryland precipitation, where a large fraction of annual rainfall is concentrated in a small number of high magnitude events. To provide process information in adequate temporal resolution the present study directly investigates percolation processes in an Eastern Mediterranean karst system, Mt. Carmel, Israel. Therefore the drip response of stalactites in a karstic cave 28m below a sprinkling experiment was measured. Besides hydrometric measurements (soil moisture, surface runoff, stalactite dripping rates) also tracers were applied. Sprinkling water was pumped from two wells of the underlying karst aquifer. The experiment took place at the end of the dry season. Simulating a series of two high intensity storms, 190 mm of artificial rainfall was sprinkled over two days on a 143 m2 plot. Two types of tracers were used: (i) the relatively high conductivity of the sprinkling water facilitated the separation between old (pre-sprinkling) and new (sprinkling) water by mixing analysis, (ii) before second day sprinkling bromide was injected as a dirac impulse on top of selected soil pockets to facilitate direct insights into percolation fluxes. On the plot surface saturation excess runoff was observed towards the end of first day sprinkling and entire soil saturation occurred down to the deepest soil moisture sensor. During the second day the entire soil reached quickly saturation and remained at field capacity until the end of data collection. In the cave the drip response depended on stalactite type: (i) perennial stalactites were already dripping continuously before sprinkling onset. Conductivity dynamics resulted in high percentages of pre-sprinkling water suggesting continuous input

  9. Estimating annual groundwater recharge coefficient for karst aquifers of the southern Apennines (Italy)

    NASA Astrophysics Data System (ADS)

    Allocca, V.; Manna, F.; De Vita, P.

    2014-02-01

    To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P - ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926-2012, the mean annual P - ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an

  10. Evaluation of subsidence hazard in mantled karst setting: a case study from Val d'Orléans (France)

    NASA Astrophysics Data System (ADS)

    Perrin, Jérôme; Cartannaz, Charles; Noury, Gildas; Vanoudheusden, Emilie

    2015-04-01

    Soil subsidence/collapse is a major geohazard occurring in karst region. It occurs as suffosion or dropout sinkholes developing in the soft cover. Less frequently it corresponds to a breakdown of karst void ceiling (i.e., collapse sinkhole). This hazard can cause significant engineering challenges. Therefore decision-makers require the elaboration of methodologies for reliable predictions of such hazards (e.g., karst subsidence susceptibility and hazards maps, early-warning monitoring systems). A methodological framework was developed to evaluate relevant conditioning factors favouring subsidence (Perrin et al. submitted) and then to combine these factors to produce karst subsidence susceptibility maps. This approach was applied to a mantled karst area south of Paris (Val d'Orléans). Results show the significant roles of the overburden lithology (presence/absence of low-permeability layer) and of the karst aquifer piezometric surface position within the overburden. In parallel, an experimental site has been setup to improve the understanding of key processes leading to subsidence/collapse and includes piezometers for measurements of water levels and physico-chemical parameters in both the alluvial and karst aquifers as well as surface deformation monitoring. Results should help in designing monitoring systems to anticipate occurrence of subsidence/collapse. Perrin J., Cartannaz C., Noury G., Vanoudheusden E. 2015. A multicriteria approach to karst subsidence hazard mapping supported by Weights-of-Evidence analysis. Submitted to Engineering Geology.

  11. Peculiarity and vulnerability of karst settings, analyzed through a review of available environmental indices

    NASA Astrophysics Data System (ADS)

    Parise, Mario; Mazzei, Marianna

    2016-04-01

    Karst is a unique environment on Earth, characterized by a variety of peculiar geological and hydrological features, that are expressed by typical landforms at the surface (doline, ponor, polje, etc.) and underground (single cave, sinkhole, complex hypogean systems consisting of sequences of pits and galleries, etc.). Among the main characters of karst, the direct connection between the surface and the underground is at the origin of the fragility of karst settings, and the related high vulnerability. Many different types of natural geological hazards (or geo-hazards) may potentially affect karst lands, with sinkholes and flash floods being the most frequent and typical. In addition, karst is exposed to a variety of anthropogenic disturbances as well, including loss of natural landscapes, destruction of caves and speleothems, and contamination and pollution problems. At this latter regard, it has to be reminded that karst aquifers host high quality groundwaters, that are used as source of drinking water worldwide, with estimates indicating that the supply of drinking water from karst is going to have a significant increase in the next decades, From all of this, the importance in fully defining the karst setting, and in a detail examination of all the natural and anthropogenic events that may cause negative effects on it, comes out. Uniqueness of karst has been acknowledged since a long time, but only in recent years efforts have been made to develop approaches and methods specifically dedicated to this peculiar environment. Such approaches represent definitely a mandatory step in the correct management of karst terranes, providing useful elements to stakeholders, land managers and people living in karst lands about their fragility, and the need to safeguard them and the natural resources therein contained. Starting from these considerations, in this contribution we review the main environmental indices dedicated to karst that have been recently proposed in the

  12. Adaptive Molecular Evolution of PHYE in Primulina, a Karst Cave Plant

    PubMed Central

    Tao, Junjie; Qi, Qingwen; Kang, Ming; Huang, Hongwen

    2015-01-01

    Limestone Karst areas possess high levels of biodiversity and endemism. Primulina is a typical component of Karst endemic floras. The high species richness and wide distribution in various Karst microenvironments make the genus an idea model for studying speciation and local adaptation. In this study, we obtained 10 full-length sequences of the phytochrome PHYE from available transcriptome resources of Primulina and amplified partial sequences of PHYE from the genomic DNA of 74 Primulina species. Then, we used maximum-likelihood approaches to explore molecular evolution of PHYE in this Karst cave plant. The results showed that PHYE was dominated by purifying selection in both data sets, and two sites were identified as potentially under positive selection. Furthermore, the ω ratio varies greatly among different functional domains of PHYE and among different species lineages. These results suggest that potential positive selection in PHYE might have played an important role in the adaption of Primulina to heterogeneous light environments in Karst regions, and different species lineages might have been subjected to different selective pressures. PMID:26030408

  13. Estimation of underground river water availability based on rainfall in the Maros karst region, South Sulawesi

    NASA Astrophysics Data System (ADS)

    Arsyad, Muhammad; Ihsan, Nasrul; Tiwow, Vistarani Arini

    2016-02-01

    Maros karst region, covering an area of 43.750 hectares, has water resources that determine the life around it. Water resources in Maros karst are in the rock layers or river underground in the cave. The data used in this study are primary and secondary data. Primary data includes characteristics of the medium. Secondary data is rainfall data from BMKG, water discharge data from the PSDA, South Sulawesi province in 1990-2010, and the other characteristics data Maros karst, namely cave, flora and fauna of the Bantimurung Bulusaraung National Park. Data analysis was conducted using laboratory test for medium characteristics Maros karst, rainfall and water discharge were analyzed using Minitab Program 1.5 to determine their profile. The average rainfall above 200 mm per year occurs in the range of 1999 to 2005. The availability of the water discharge at over 50 m3/s was happened in 1993 and 1995. Prediction was done by modeling Autoregressive Integrated Moving Average (ARIMA), with the rainfall data shows that the average precipitation for four years (2011-2014) will sharply fluctuate. The prediction of water discharge in Maros karst region was done for the period from January to August in 2011, including the type of 0. In 2012, the addition of the water discharge started up in early 2014.

  14. Hydrological role of karst in the Chalk aquifer of Upper Normandy, France

    NASA Astrophysics Data System (ADS)

    El Janyani, Sanae; Dupont, Jean-Paul; Massei, Nicolas; Slimani, Smail; Dörfliger, Nathalie

    2014-05-01

    The role of karst on large-scale groundwater flow is defined for the Chalk aquifer of Upper Normandy (western Paris Basin), France. In the regional context, chalk plateaus occupy the greater part of watersheds and are the main sites of groundwater recharge. Previous studies focused on karstic output systems in the valleys and less on water-level variations in the recharge zones upstream. This study assesses the relevant hydrogeological processes using time-series data (boreholes and springs) recorded along a down-gradient hydrologeological cross-section in two selected watersheds. These hydrological data are interpreted in the framework of previous descriptions of the morphological organization of the study area's karst network. The results highlight the hydrological role of (1) the input karst (vertical conduits) which drains recharging water, (2) the output karst (sub-horizontal conduits widely developed in the vicinity of valleys in the surface watersheds) which drains the output flows, and (3) the connections between these two (input and output) networks, which control the upstream water levels and allow quick transfer to springs, particularly after strong rainfall events. A conceptual model of the hydrological functioning of this covered karst aquifer is established, which should serve for the structuring and parameterization of a numerical model.

  15. Adaptive Molecular Evolution of PHYE in Primulina, a Karst Cave Plant.

    PubMed

    Tao, Junjie; Qi, Qingwen; Kang, Ming; Huang, Hongwen

    2015-01-01

    Limestone Karst areas possess high levels of biodiversity and endemism. Primulina is a typical component of Karst endemic floras. The high species richness and wide distribution in various Karst microenvironments make the genus an idea model for studying speciation and local adaptation. In this study, we obtained 10 full-length sequences of the phytochrome PHYE from available transcriptome resources of Primulina and amplified partial sequences of PHYE from the genomic DNA of 74 Primulina species. Then, we used maximum-likelihood approaches to explore molecular evolution of PHYE in this Karst cave plant. The results showed that PHYE was dominated by purifying selection in both data sets, and two sites were identified as potentially under positive selection. Furthermore, the ω ratio varies greatly among different functional domains of PHYE and among different species lineages. These results suggest that potential positive selection in PHYE might have played an important role in the adaption of Primulina to heterogeneous light environments in Karst regions, and different species lineages might have been subjected to different selective pressures.

  16. [Variation Characteristics and Sources of Heavy Metals in an Urban Karst Groundwater System during Rainfall Event].

    PubMed

    Ren, Kun; Yang, Ping-heng; Jiang, Ze-li; Wang, Zun-bo; Shi, Yang; Wang, Feng-kang; Li, Xiao-chun

    2015-04-01

    The groundwater discharge and heavy metal concentrations (Mn, Pb, Cu and As) at the outlet of Nanshan Laolongdong karst subterranean river, located at the urban region in Chongqing, were observed during the rainfall events. Analysis of flow and concentrations curves was employed to study their responses to the rainfall events and explore the internal structure of karst hydrological system. Principal component analysis (PCA) and measurements were used to identify the sources of heavy metals during rainfall. The result showed that the discharge and concentrations of the heavy metals responded promptly to the rainfall event. The variation characteristics of flow indicated that Laolongdong subterranean river system belonged to a karst hydrological system including fractures together with conduits. Urban surface runoff containing large amounts of Mn, Pb and Cu went directly to subterranean river via sinkholes, shafts and karst windows. As a result, the peak concentrations of contaminants (Mn, Pb and Cu) flowed faster than those of discharge. The major sources of water pollution were derived from urban surface runoff, soil and water loss. Cave dripwater and rainwater could also bring a certain amount of Mn, Pb and As into the subterranean river. Urban construction in karst areas needs scientific and rational design, perfect facilities and well-educated population to prevent groundwater pollution from the source.

  17. Validation of a numerical indicator of microbial contamination for karst springs.

    PubMed

    Butscher, Christoph; Auckenthaler, Adrian; Scheidler, Stefan; Huggenberger, Peter

    2011-01-01

    Rapid changes in spring water quality in karst areas due to rapid recharge of bacterially contaminated water are a major concern for drinking water suppliers and users. The main objective of this study was to use field experiments with fecal indicators to verify the vulnerability of a karst spring to pathogens, as determined by using a numerical modeling approach. The groundwater modeling was based on linear storage models that can be used to simulate karst water flow. The vulnerability of the karst groundwater is estimated using such models to calculate criteria that influence the likelihood of spring water being affected by microbial contamination. Specifically, the temporal variation in the vulnerability, depending on rainfall events and overall recharge conditions, can be assessed and quantified using the dynamic vulnerability index (DVI). DVI corresponds to the ratio of conduit to diffuse flow contributions to spring discharge. To evaluate model performance with respect to predicted vulnerability, samples from a spring were analyzed for Escherichia coli, enterococci, Clostridium perfringens, and heterotrophic plate count bacteria during and after several rainfall events. DVI was shown to be an indication of the risk of fecal contamination of spring water with sufficient accuracy to be used in drinking water management. We conclude that numerical models are a useful tool for evaluating the vulnerability of karst systems to pathogens under varying recharge conditions.

  18. [Study on the relation between fraction cover and mixed spectra in karst environment].

    PubMed

    Liu, Bo; Yue, Yue-min; Li, Ru; Wang, Ke-lin; Zhang, Bing; Tong, Qing-xi

    2010-09-01

    Karst rocky desertification is one of the most serious eco-environmental problems of land degradation in karst regions, southwest China. The fractional cover of vegetation and exposed bedrock are the main land surface symptoms and essential assessing indicators of karst rocky desertification. To assess the extent of rocky desertification in complex karst environments, the information of multiple land cover types fraction is needed. Based on in situ spectral reflectance data, this study proposed several spectral indices and explored the relationship between spectral features of main land cover types and their responding fractional cover. The results showed that spectral indices have much higher correlation coefficients with fractional cover than does spectral reflectance. Vegetation indices have good linear relation with fractional cover of photosynthetic vegetation (PV). The proposed spectral indices have high correlation coefficients with fractional cover of non-photosynthetic vegetation (NPV) and bare soil, with R2 0.70 and 0.73, respectively. Lower correlation coefficients (R2 = 0.55) with the factional cover of exposed bedrock, were observed. The absorption depth of four forms of the proposed indices has the highest correlation coefficient with the fractional cover of NPV, bare soil, and exposed rock. This study indicates that hyperspectral remote sensing has the potential for the extraction of karst rocky desertification information.

  19. Characterisation of dissolved organic matter in karst spring waters using intrinsic fluorescence: relationship with infiltration processes.

    PubMed

    Mudarra, M; Andreo, B; Baker, A

    2011-08-15

    From analysis of spectrophotometric properties of dissolved organic matter (OM) and the hydrochemical responses of some karst springs under different hydrologic conditions, an assessment of the origin and transfer pathway of OM present in karst spring waters, from soil and epikarst toward the spring, has been conducted for three karst aquifers in southern Spain: Alta Cadena, Sierra de Enmedio and Los Tajos. Intrinsic fluorescence (excitation-emission matrices or EEMs), together with major water chemistry (electrical conductivity, temperature, alkalinity, Cl⁻, Mg⁺²) and P(CO₂) along with natural hydrochemical tracers (TOC and NO₃⁻, have been monitored in 19 springs which drain the three karst aquifers examined in this study. The spring water EEM spectra indicate that fulvic acid-like substances, produced in the soil as a consequence of the decomposition of OM, are the dominant fluorophores, although some of the OM appears to originate from in situ microbiological activity but could be indicative of contamination present in recharge waters from livestock. During each recharge event, TOC and NO₃⁻ concentrations increased and variations in fluorescence intensities of peaks attributed to fulvic acid-like compounds were observed. In areas with minimal soil development, spatial and temporal variations in the fluorescence intensity of fulvic acid-like substances and other fluorophores derived from microbiological activity, together with other hydrochemical parameters, provide insights into the hydrogeological functioning of karst aquifers and the infiltration velocity of water from soil and facilitate assessment of contamination vulnerability in these aquifers.

  20. Sagging and collapse sinkholes over hypogenic hydrothermal karst in a carbonate terrain

    NASA Astrophysics Data System (ADS)

    Frumkin, Amos; Zaidner, Yossi; Na'aman, Israel; Tsatskin, Alexander; Porat, Naomi; Vulfson, Leonid

    2015-01-01

    We show that clusters of karst sinkholes can occur on carbonate hypogene karst terrains. Unlike common doline karst of dissolution origin, the studied sinkholes form mainly by sagging and collapse. Thermal survey, OSL dating and morphologic analysis during quarrying and excavations are applied to study the sinkholes at the Ayyalon karst, Israel. The thermal survey shows the spatial pattern of rising warm water plumes, whose temperature is > 2 °C warmer than the surrounding aquifer water. These plumes dissolve the limestone, creating large voids and maze caves. Mass wasting forms surface sinkholes mainly by sagging and collapse. Both types of deformation often occur within the same depression. Lack of hydrologic connection between the surface and underground voids constrain drainage and promote rapid accumulation of colluvium, dust and pedogenic clays. These have filled the sinkholes up to their rim before the late Holocene. OSL dating constrains the rate of sediment accumulation within the sinkholes. The average filling rate (thickness divided by elapsed time) is ~ 47 mm ka- 1 for the last 53 ± 4 ka in Sinkhole 1, while in Sinkhole 2 ("Nesher Ramla karst depression"), the rate is ~ 61 mm ka- 1 from ~ 200 to 78 ka, and ~ 173 mm ka- 1 since ~ 78 ka. Between ~ 170 and 78 ka, Sinkhole 2 was intensively used by Middle Paleolithic hominins. The studied sinkholes may be considered as a type locality for hypogene sinkhole terrain on carbonate rocks.

  1. Chemograph analysis of two herbicides in a German karst aquifer

    NASA Astrophysics Data System (ADS)

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2013-04-01

    The dynamic of spring discharge of mature karst aquifers shows after strong precipitation events: Karst spring discharge increases rapidly and strongly, the chemical composition of the spring water is altered and contaminants may be transported from the land-surface towards the spring with the percolating rainwater. Contrary to rapid water transport, high travel times have been observed for parts of the spring discharge, employing stable isotopes as indicators. Monitoring the concentrations of Ca2+ and Cl- in spring water after a precipitation event one may observe the following: After a first increase, the concentrations of Ca2+ drop below the pre-event value, due to dilution with lowly mineralized rain water. On the other hand the concentrations of Cl- increase quickly and return to their background values nearly as fast. This difference in behavior arises from the different origins of these two inorganic ions. Ca2+ in spring water originates mainly from the dissolution of the carbonatic bedrock, while Cl- might be transported from the land-surface (e.g. from road salt) towards the spring. To investigate the dynamic of water in the Gallusquelle catchment in southwest Germany a one year sampling campaign was conducted, using different herbicides as indicator compounds. Depending on discharge conditions the sampling interval varied between 3 hours and several days. Among others, the currently applied and chemically unstable metazachlor was observed together with atrazine, which is prohibited since more than 20 years in Germany. While the detection frequency of atrazine in the spring water samples was nearly 100%, the concentrations ranged only up to 5.2 ng/L. On the other hand, the currently applied metazachlor was only detected in 30.7% of the samples, but its maximum concentration was 71.9 ng/L. An interesting feature was the different temporal concentration pattern of the two investigated herbicides: After precipitation events the concentration of metazachlor in

  2. U.S. Geological Survey Karst Interest Group Proceedings, Carlsbad, New Mexico, April 29-May 2, 2014

    USGS Publications Warehouse

    Kuniansky, Eve L.; Spangler, Lawrence E.; Kuniansky, Eve L.; Spangler, Lawrence E.

    2014-01-01

    Introduction and Acknowledgments Karst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex, and involve biological, chemical, and physical changes. These factors, combined with the diverse climatic regimes under which karst development in these rocks has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains. The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs has resulted in the most exceptional karst areas of the United States being designated as national or state parks; commercial caverns and known privately owned caves number in the tens of thousands. Both public and private properties provide access for scientists to study the flow of groundwater in situ. Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these karst hydrogeologic systems. As a result, numerous federal

  3. SP Monitoring of Intermittent Flow Through Covered-Karst Sinkholes

    NASA Astrophysics Data System (ADS)

    Bumpus, P. B.; Kruse, S. E.

    2010-12-01

    A year of continuous SP (self-potential) monitoring was combined with high-resolution 3-D GPR surveys and intermittent water table monitoring over two small covered-karst conduits in Tampa, Florida. SP readings were logged over ~30 electrodes at 2-minute intervals. Positive and negative SP anomalies episodically manifested over conduits, suggesting that conduit flow is dynamic, not static. Three distinct SP flow regimes in the conduits are postulated: fast flow through the conduit to the underlying aquifer, slow flow to the confining layer through the collapse conduit walls, and a conduit plugged high enough to behave like the rest of the confining layer. SP responses after rain events appear to measure the effects of two wetting front curves, one striking the monitoring electrode, one the reference. By comparing curve shapes for all possible pairs of electrodes, it may be possible to establish surficial infiltration and flow patterns. SP is also strongly affected by soil conductivity, rainfall history, and cultural noise. Further concurrent study of moisture content and SP with a suite of reference electrodes placed in various topographic, vegetative, geologic, and climatic settings will help distinguish groundwater flow from other sources affecting SP measurements.

  4. Chemical fluctuations in karst springflow storm responses, southeastern Missouri

    SciTech Connect

    Dreiss, S.J.; Summa, C.L.

    1985-01-01

    The interaction between groundwater flow in conduits and in pores in well-developed karst regions is complex and poorly understood. Chemical analyses of springflow samples, collected at 4 to 24 hour intervals from two large springs in southeastern Missouri, enable interpretation of the mechanics of this interaction. Ca and Mg concentrations in spring discharge exhibit distinct seasonal trends; large variations are superimposed in response to storms. Initial, rapid, oscillatory fluctuations in concentration occur generally coincident with the hydrograph peak for a given event. Interestingly, concentrations then decrease during hydrograph recession. Recovery to pre-event baseline concentrations requires several weeks for large events. Initial oscillations in discharge chemistry probably result from rapid, local recharge to the system through sinkholes, swallow holes and fractures near the spring outlet. The chemical response observed during hydrograph recession results from transport of lesser saturated waters through a regional fracture network. The arrival time of these low concentration waters is consistent with measured tracer travel times from previously delineated regional recharge areas. Thus, the lesser saturated waters represent a regionally transported pulse derived, in part, from the rainfall event.

  5. [Hydrogeochemical characteristics of a typical karst groundwater system in Chongqing].

    PubMed

    Yang, Ping-Heng; Lu, Bing-Qing; He, Qiu-Fang; Chen, Xue-Bin

    2014-04-01

    The two-year hydrologic process, hydrochemistry, and a portion of deltaD, delta18O of both the surface water at the inlet and the groundwater at the outlet, were investigated to identify the spatial and temporal variations of hydrogeochemistry in the Qingmuguan karst groundwater system. Research results show that there are wet and dry periods in the groundwater system owing to the striking influence of seasonal rainfall. The evolution of the chemical compositions in the groundwater is significantly influenced by the water and rock interaction, anthropogenic activities and rainwater dilution. The variations of the chemical compositions in the groundwater exhibit obvious spatiality and temporality. The deltaD and delta18O of the surface water beneath the local Meteoric Water Line of Chonqing indicate that the surface water is strongly evaporated. Furthermore, the deltaD and delta18O of the surface water are more positive in the dry period than in the wet period, showing a distinct seasonal effect. The deltaD and delta18O of the groundwater are quite stable and much negative compared with those of the surface water, which suggests that the rainwater recharge the groundwater via two pathways, one directly through sinkholes and the other via the vadose zone.

  6. Drinking water treatment for a rural karst region in Indonesia

    NASA Astrophysics Data System (ADS)

    Matthies, K.; Schott, C.; Anggraini, A. K.; Silva, A.; Diedel, R.; Mühlebach, H.; Fuchs, S.; Obst, U.; Brenner-Weiss, G.

    2016-09-01

    An interdisciplinary German-Indonesian joint research project on Integrated Water Resources Management (IWRM) focused on the development and exemplary implementation of adapted technologies to improve the water supply situation in a model karst region in southern Java. The project involving 19 sub-projects covers exploration of water resources, water extraction, distribution as well as water quality assurance, and waste water treatment. For the water quality assurance, an appropriate and sustainable drinking water treatment concept was developed and exemplarily implemented. Monitoring results showed that the main quality issue was the contamination with hygienically relevant bacteria. Based on the gained results, a water treatment concept was developed consisting of a central sand filtration prior to the distribution network, a semi-central hygienization where large water volumes are needed to remove bacteria deriving from water distribution and a final point-of-use water treatment. This paper focuses on the development of a central sand filtration plant and some first analysis for the development of a recipe for the local production of ceramic filters for household water treatment. The first results show that arsenic and manganese are leaching from the filters made of local raw material. Though discarding the first, filtrates should be sufficient to reduce arsenic and manganese concentration effectively. Moreover, hydraulic conductivities of filter pots made of 40 % pore-forming agents are presented and discussed.

  7. Permian karst topography in the Wichita uplift, southwestern Oklahoma

    SciTech Connect

    Donovan, R.N. Busbey, A.B. . Geology Dept.)

    1993-02-01

    The Wichita uplift in southwestern Oklahoma is one part of a record of Pennsylvania and early Permian deformation that affected the Southern Oklahoma aulacogen. As a result of a partial inversion, the Lower Paleozoic section of this aulacogen was sequentially stripped off an uplift between the Wichita uplift and the Anadarko basin, resulting in the exposure of ultrabasic rocks deep in the Cambrian igneous fill of the aulacogen. Following the late Paleozoic tectonism, the topography of the uplift was entombed beneath Permian sediments and remained essentially undisturbed until exhumation during the present erosional cycle. Modern erosion is gradually exposing this topography, permitting morphometric analysis of the Permian hill forms. Because of the variation of lithology in the uplift, it is possible to isolate the effects of weathering processes such as intense hydrolysis of the igneous rocks (producing, among other features, or topography) and limestone dissolution, in the form of a surface and subsurface karst imprint. The latter process resulted in a network of small caves that are essentially fissures eroded along tectonic fractures. These small caves can be found in all the exposed areas of limestone. They are particularly noteworthy for three reasons: in at least five examples they contain a complex fauna of Permian vertebrates (mostly fragmentary), speleothems in some examples contain hydrocarbon inclusions, derived from the underlying Anadarko basin, some of the caves yield evidence of post burial evolution in the form of clay infiltration from the surface and brine flushing from the underlying Anadarko basin.

  8. Karst Groundwater Hydrologic Analyses Based on Aerial Thermography

    NASA Technical Reports Server (NTRS)

    Campbell, C. Warren; Keith, A. G.

    2000-01-01

    On February 23, 1999, thermal imagery of Marshall Space Flight Center, Alabama was collected using an airborne thermal camera. Ground resolution was I in. Approximately 40 km 2 of thermal imagery in and around Marshall Space Flight Center (MSFC) was analyzed to determine the location of springs for groundwater monitoring. Subsequently, forty-five springs were located ranging in flow from a few ml/sec to approximately 280 liter/sec. Groundwater temperatures are usually near the mean annual surface air temperature. On thermography collected during the winter, springs show up as very warm spots. Many of the new springs were submerged in lakes, streams, or swamps; consequently, flow measurements were difficult. Without estimates of discharge, the impacts of contaminated discharge on surface streams would be difficult to evaluate. An approach to obtaining an estimate was developed using the Environmental Protection Agency (EPA) Cornell Mixing Zone Expert System (CORMIX). The thermography was queried to obtain a temperature profile down the center of the surface plume. The spring discharge was modeled with CORMIX, and the flow adjusted until the surface temperature profile was matched. The presence of volatile compounds in some of the new springs also allowed MSFC to unravel the natural system of solution cavities of the karst aquifer. Sampling results also showed that two springs on either side of a large creek had the same water source so that groundwater was able to pass beneath the creek.

  9. Locating groundwater flow in karst by acoustic emission surveys

    SciTech Connect

    Stokowski, S.J. Jr.; Clark, D.A.

    1985-01-01

    An acoustic emission survey of Newala Fm. (primarily dolomite) karst has helped to locate subsurface water flow. This survey was performed on the Rock Quarry Dome, Sevier County, Tennessee. A Dresser RS-4 recording seismograph, adjusted to provide a gain of 1000, collected acoustic emission data using Mark Products CN368 vertical geophones with 3-inch spikes. Data was collected for 5-15 second intervals. The geophones were laid out along traverses with 10, 20, or 30-ft spacing and covered with sand bags in locations of high ambient noise. Traverses were laid out: along and across lineaments known to correspond with groundwater flow in natural subsurface channels; across and along a joint-controlled sink suspected of directing groundwater flow; and across a shallow sinkhole located tangentially to the Little Pigeon River and suspected of capturing river water for the groundwater system. Acoustic emissions of channelized flowing groundwater have a characteristic erratic spiked spectral signature. These acoustic emission signatures increase in amplitude and number in the immediate vicinity of the vertical projection of channelized groundwater flow if it occurs within approximately 30 feet of the surface. If the groundwater flow occurs at greater depths the emissions may be offset from the projection of the actual flow, due to propagation of the signal along rock pinnacles or attenuation by residual soils.

  10. Drinking water treatment for a rural karst region in Indonesia

    NASA Astrophysics Data System (ADS)

    Matthies, K.; Schott, C.; Anggraini, A. K.; Silva, A.; Diedel, R.; Mühlebach, H.; Fuchs, S.; Obst, U.; Brenner-Weiss, G.

    2016-06-01

    An interdisciplinary German-Indonesian joint research project on Integrated Water Resources Management (IWRM) focused on the development and exemplary implementation of adapted technologies to improve the water supply situation in a model karst region in southern Java. The project involving 19 sub-projects covers exploration of water resources, water extraction, distribution as well as water quality assurance, and waste water treatment. For the water quality assurance, an appropriate and sustainable drinking water treatment concept was developed and exemplarily implemented. Monitoring results showed that the main quality issue was the contamination with hygienically relevant bacteria. Based on the gained results, a water treatment concept was developed consisting of a central sand filtration prior to the distribution network, a semi-central hygienization where large water volumes are needed to remove bacteria deriving from water distribution and a final point-of-use water treatment. This paper focuses on the development of a central sand filtration plant and some first analysis for the development of a recipe for the local production of ceramic filters for household water treatment. The first results show that arsenic and manganese are leaching from the filters made of local raw material. Though discarding the first, filtrates should be sufficient to reduce arsenic and manganese concentration effectively. Moreover, hydraulic conductivities of filter pots made of 40 % pore-forming agents are presented and discussed.

  11. Karst development and speleogenesis, Isla de Mona, Puerto Rico

    USGS Publications Warehouse

    Frank, E.F.; Mylroie, J.; Troester, J.; Alexander, E.C.; Carew, J.L.

    1998-01-01

    Isla de Mona consists of a raised table-top Miocene-Pliocene reef platform bounded on three sides by vertical cliffs, up to 80 m high. Hundreds of caves ring the periphery of the island and are preferentially developed in, but not limited to, the Lirio Limestone/Isla de Mona Dolomite contact. These flank margin caves originally formed at sea level and are now exposed at various levels by tectonic uplift of the island (Franbk 1983; Mylroie et al. 1995b). Wall cusps, a characteristic feature of flank margin caves, are ubiquitois features. Comparisons among similar caves formed in the Bahamas and Isla de Mona reveal the same overall morphology throughout the entire range of sizes and complexities. The coincidence of the primary cave development zone with the Lirio Limestone/Isla de Mona Dolomite contact may result from syngenetic speleogenesis and dolomitization rather than preferential dissolution along a lithologic boundary. Tectonic uplift and glacioeustatic sea level fluctuations produced caves at a variety of elevations. Speleothem dissolution took place in many caves under phreatic conditions, evidence these caves were flooded after an initial period of subaerial exposure and speleothem growth. Several features around the perimeter of the island are interpreted to be caves whose roofs were removed by surficial denudation processes. Several large closed depressions and dense pit cave fields are further evidence of surficial karst features. The cliff retreat around the island perimeter since the speleogenesis of the major cave systems is small based upon the distribution of the remnant cave sections.

  12. Hydrological and Ecological Problems of Karst Regions: Hydrological actions on limestone regions cause distinctive ecological problems.

    PubMed

    Legrand, H E

    1973-03-01

    Climate exerts a universal dominant influence on ecology, but processes of karstification have an equally high ecological influence in carbonate rock regions. Development of karst features depends greatly on the degree to which water containing carbon dioxide has been able to move on and through carbonate rocks and to remove some of the rock in solution. Distinctive features of many karst terranes include scarcity of soils, scarcity of surface streams, and rugged topography; less distinctive are the highly permeable and cavernous rocks, especially at the shallow depths. This high permeability gives rise to many practical problems, including (i) scarcity and poor predictability of groundwater supplies, (ii) scarcity of surface streams, (iii) instability of the ground, (iv) leakage of surface reservoirs, and (v) an unreliable waste-disposal environment. Natural karst processes in some carbonate rock regions have caused a greater restriction in the development of biota than man can ever be suspected of causing.

  13. Methods for karst hazard forecast and pipeline protection in South Yakutia

    NASA Astrophysics Data System (ADS)

    Strokova, L. A.; Teterin, E. A.

    2015-11-01

    The objective of this paper is to consider the ways of monitoring and protecting the pipeline «The Power of Siberian from karst hazards. The method of protection with bored piles has been recommended and the forecasting methods have been overviewed. Thus, ground penetrating radar allows discovering a soil cavity when the overburden layer is not very deep and predicting sinkhole collapse when used in combination with a balance arch model. Monitoring of triggering factors is widely used to forecast karst collapse when the opening is caused by pumping as the data on dynamic groundwater conditions can be obtained in realtime. However, the suggested protection method is expensive and some forecasts might be difficult to make. The authors have suggested the ways to improve the current situation and to reduce the damage caused by karst collapse.

  14. Late Pleistocene-early Holocene karst features, Laguna Madre, south Texas: A record of climate change

    SciTech Connect

    Prouty, J.S.

    1996-09-01

    A Pleistocene coquina bordering Laguna Madre, south Texas, contains well-developed late Pleistocene-early Holocene karst features (solution pipes and caliche crusts) unknown elsewhere from coastal Texas. The coquina accumulated in a localized zone of converging longshore Gulf currents along a Gulf beach. The crusts yield {sup 14}C dates of 16,660 to 7630 B.P., with dates of individual crust horizons becoming younger upwards. The karst features provide evidence of regional late Pleistocene-early Holocene climate changes. Following the latest Wisconsinan lowstand 18,000 B.P. the regional climate was more humid and promoted karst weathering. Partial dissolution and reprecipitation of the coquina formed initial caliche crust horizons; the crust later thickened through accretion of additional carbonate laminae. With the commencement of the Holocene approximately 11,000 B.P. the regional climate became more arid. This inhibited karstification of the coquina, and caliche crust formation finally ceased about 7000 B.P.

  15. Fractal dimension, walk dimension and conductivity exponent of karst networks around Tulum.

    NASA Astrophysics Data System (ADS)

    Hendrick, Martin; Renard, Philippe

    2016-06-01

    Understanding the complex structure of karst networks is a challenge. In this work, we characterize the fractal properties of some of the largest coastal karst network systems in the world. They are located near the town of Tulum (Quintana Roo, Mexico). Their fractal dimension d_f, conductivity exponent tilde{mu} and walk dimension d_w are estimated using real space renormalization and numerical simulations. We obtain the following values for these exponents: d_f≈ 1.5, d_w≈ 2.4, tilde{mu}≈ 0.9. We observe that the Einstein relation holds for these structures tilde{mu} ≈ -d_f + d_w. These results indicate that coastal karst networks can be considered as critical systems and this provides some foundations to model them within this framework.

  16. Possible karst landforms in two unnamed craters in Tyrrhena Terra, Mars

    NASA Astrophysics Data System (ADS)

    Baioni, Davide; Tramontana, Mario

    2016-11-01

    Tyrrhena Terra, an area in the cratered highlands south of the Martian equator, contains two unnamed craters. The mineralogical composition of light-toned deposits (LTDs) within these craters is unknown. We performed morphologic and morphometric analyses of the surfaces of these LTDs through an integrated study of images available through the Reconnaissance Mars Orbiter High-Resolution Imaging Science Experiment. Our analysis revealed that the Martian landforms contain dolines of polygenetic origin. These dolines are similar to karst landforms observed in different karst terrains on Earth and other regions on Mars. The observed karst landforms might highlight the possible evaporitic origin of these materials, suggesting a climatic change and the presence of liquid water caused by ice melting during the Amazonian age.

  17. Mobile sediment in an urbanizing karst aquifer: Implications for contaminant transport

    USGS Publications Warehouse

    Mahler, B.J.; Lynch, L.; Bennett, P.C.

    2000-01-01

    Here we investigate geochemical characteristics of sediment in different compartments of a karst aquifer and demonstrate that mobile sediments in a karst aquifer can exhibit a wide range of properties affecting their contaminant transport potential. Sediment samples were collected from surface streams, sinkholes, caves, wells, and springs of a karst aquifer (the Barton Springs portion of the Edwards (Balcones Fault Zone) Aquifer, Central Texas) and their mineralogy, grain-size distribution, organic carbon content, and specific surface area analyzed. Statistical analysis of the sediments separated the sampling sites into three distinct groups: (1) streambeds, sinkholes, and small springs; (2) wells; and (3) caves. Sediments from the primary discharge spring were a mix of these three groups. High organic carbon content and increased potential to transport contaminants; the volume of these sediments is likely to increase with continued urbanization of the watershed.

  18. Application of a discrete-continuum model to karst aquifers in North China.

    PubMed

    Wu, Qiang; Zhou, Wanfang; Pan, Guoying; Ye, Siyuan

    2009-01-01

    A generalized discrete-continuum model is developed to simulate ground water flow in the karst aquifers of North China. The model is a hybrid numerical flow model, which takes into account both quick conduit flow and diffusive fissure flow. The conduit flow is represented by a discrete network model, and the fissure flow is modeled by a continuum approach. The developed model strongly emphasizes the function of the conduits in the flow fields. They control the general drainage pattern, as demonstrated in the simulation of a complex karst aquifer in North China. The model reproduces reasonably well the flow field in response to an unanticipated discharge of ground water from the karst aquifer into an underground mine based on the aquifer parameters that are manually calibrated from a multiple-well pumping test. Sensitivity of the model to the aquifer parameters was evaluated in the context of the case study.

  19. Identification of the attenuation potential of a karst aquifer by an artificial dualtracer experiment with caffeine.

    PubMed

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2012-10-15

    Little is known with respect to the attenuation capacity of karst aquifers. Even less is known about the risk posed by emerging micropollutants in these systems. In order to identify the attenuation potential of karst aquifers in-situ and to estimate the risk posed by micropollutants, a dualtracer test was conducted in this study in order to investigate differential transport in the subsurface: The reactive compound caffeine was used as a tracer to indicate the attenuation capacity within the aquifer in-situ. Due to the low limit of quantification, only small amounts of caffeine needed to be injected. To calibrate a model and to visualize the attenuation of caffeine a conservative reference tracer (uranine) is injected simultaneously. The methodology is tested in a well-characterised karst system in southwest Germany. The results indicate a significantly higher attenuation rate than was expected for karst aquifers. The attenuation is decribed as a first-order process. The corresponding half-life is 104 h. This low half-life suggests that a generally assumed low natural attenuation capacity of karst aquifers is unjustified. The observed mass loss of caffeine illustrates the potential of caffeine to be used as reactive tracer for indicating in-situ attenuation capacity within highly hydraulically conductive systems, such as karst aquifers. Due to the high attenuation rate of caffeine it does not pose a threat as a long-time contaminant. In combination with a conservative reference tracer an economical and environmentally benign method is presented in this manuscript for the in-situ determination of the attenuation capacity of highly conductive aquifer systems.

  20. Identification of the attenuation potential of a karst aquifer by an artificial dualtracer experiment with caffeine.

    PubMed

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2012-10-15

    Little is known with respect to the attenuation capacity of karst aquifers. Even less is known about the risk posed by emerging micropollutants in these systems. In order to identify the attenuation potential of karst aquifers in-situ and to estimate the risk posed by micropollutants, a dualtracer test was conducted in this study in order to investigate differential transport in the subsurface: The reactive compound caffeine was used as a tracer to indicate the attenuation capacity within the aquifer in-situ. Due to the low limit of quantification, only small amounts of caffeine needed to be injected. To calibrate a model and to visualize the attenuation of caffeine a conservative reference tracer (uranine) is injected simultaneously. The methodology is tested in a well-characterised karst system in southwest Germany. The results indicate a significantly higher attenuation rate than was expected for karst aquifers. The attenuation is decribed as a first-order process. The corresponding half-life is 104 h. This low half-life suggests that a generally assumed low natural attenuation capacity of karst aquifers is unjustified. The observed mass loss of caffeine illustrates the potential of caffeine to be used as reactive tracer for indicating in-situ attenuation capacity within highly hydraulically conductive systems, such as karst aquifers. Due to the high attenuation rate of caffeine it does not pose a threat as a long-time contaminant. In combination with a conservative reference tracer an economical and environmentally benign method is presented in this manuscript for the in-situ determination of the attenuation capacity of highly conductive aquifer systems. PMID:22877878

  1. The use of karst geomorphology for planning, hazard avoidance and development in Great Britain

    NASA Astrophysics Data System (ADS)

    Cooper, Anthony H.; Farrant, Andrew R.; Price, Simon J.

    2011-11-01

    Within Great Britain five main types of karstic rocks - dolomite, limestone, chalk, gypsum and salt - are present. Each presents a different type and severity of karstic geohazard which are related to the rock solubility and geological setting. Typical karstic features associated with these rocks have been databased by the British Geological Survey (BGS) with records of sinkholes, cave entrances, stream sinks, resurgences and building damage; data for more than half of the country has been gathered. BGS has manipulated digital map data, for bedrock and superficial deposits, with digital elevation slope models, superficial deposit thickness models, the karst data and expertly interpreted areas, to generate a derived dataset assessing the likelihood of subsidence due to karst collapse. This dataset is informed and verified by the karst database and marketed as part of the BGS GeoSure suite. It is currently used by environmental regulators, the insurance and construction industries, and the BGS semi-automated enquiry system. The database and derived datasets can be further combined and manipulated using GIS to provide other datasets that deal with specific problems. Sustainable drainage systems, some of which use soak-aways into the ground, are being encouraged in Great Britain, but in karst areas they can cause ground stability problems. Similarly, open loop ground source heat or cooling pump systems may induce subsidence if installed in certain types of karstic environments such as in chalk with overlying sand deposits. Groundwater abstraction also has the potential to trigger subsidence in karst areas. GIS manipulation of the karst information is allowing Great Britain to be zoned into areas suitable, or unsuitable, for such uses; it has the potential to become part of a suite of planning management tools for local and National Government to assess the long term sustainable use of the ground.

  2. First cavernicolous trechine beetle discovered in Guilin karst, northeastern Guangxi (Coleoptera, Carabidae, Trechinae)

    PubMed Central

    Sun, Feifei; Tian, Mingyi

    2015-01-01

    Abstract A new subgenus and new species of anophthalmic trechine beetles, Oodinotrechus (Pingleotrechus) yinae subgen. n., sp. n., is described and illustrated from a limestone cave called Chaotianyan in southern part of Guilin karst, northeastern Guangxi Zhuang Autonomous Region. The new taxon is very different from the Maolan-Mulun congeners belonging to the nominate subgenus Oodinotrechus (s. str.) Uéno, 1998, in several important character states including pronotal structure, elytral chaetotaxy and male genitalia. It is the first record of a cavernicolous trechine beetle in Guilin karst, and in the eastern part of Guangxi. In addition, a distribution map for the genus Oodinotrechus Uéno, 1998, is provided. PMID:26798298

  3. Natural and Artificial (fluorescent) Tracers to Characterise Hydrogeological Functioning and to Protect Karst Aquifers

    NASA Astrophysics Data System (ADS)

    Andreo, B.

    2013-12-01

    Bartolomé Andreo; andreo@uma.es Co-workers: Matías Mudarra, Ana Isabel Marín and Juan Antonio Barberá Centre of Hydrogeology and Department of Geology. University of Malaga. http://cehiuma.uma.es/ The hydrogeological functioning and response of karst aquifers can be determined by the combined use of natural hydrogeochemical tracers, especially Total Organic Carbon (TOC) and intrinsic fluorescence of water, together with artificial (fluorescent) tracers; all them under the same hydrodynamic conditions. Sharp and rapid variations in discharge, temperature, electrical conductivity and water chemistry, particularly of natural tracers of infiltration (TOC, intrinsic fluorescence and NO3-) recorded in karst spring waters suggest the existence of a conduit flow system, with rapid flows and very short transit times from the surface to the springs. This is in agreement with the evidences obtained from breakthrough curves of fluorescent dye tracers. However, each type of tracer provides information about different aspects of the system in response to rainfall: natural tracers show the global response of the entire recharge area, while dye tracers reflect the response to concentrated recharge from specific points on the surface (karst swallow holes). Recent experiences on time lags between maximum concentrations of natural (especially TOC and intrinsic fluorescence) and artificial tracers has demonstrated that the global system response is faster and more sensitive than that produced from infiltration concentrated at a single point on the surface, even in karst sinkholes. Both natural and dye tracers permit to estimate response and transit times of water through the karst, but flow velocities can only be quantified using artificial tracers. These findings are crucial for water resources management and protection, with particular emphasis in the functioning of the aquifer and the different rates of response to input signals. Analysis of the responses obtained by natural

  4. Wellhead protection in confined, semi-confined, fractured and karst aquifer settings

    SciTech Connect

    Not Available

    1993-09-01

    Protection areas around wells producing from confined, fractured, and karst aquifers are, because of their complex hydrogeology, more difficult to define than protection areas for wells in porous media settings. The factsheet provides background information explaining the need to define protection areas for wells that draw public drinking water from several complex hydrogeologic settings: confined, semi-confined, fractured, and karst aquifers. These settings include aquifers in which the ground water is not open to the atmosphere, or the aquifer does not consist of unconsolidated porous media. Several figures illustrate these settings in a general way.

  5. Stable isotope analysis of the karst hydrological systems in the Bay of Kvarner (Croatia).

    PubMed

    Mance, D; Hunjak, T; Lenac, D; Rubinić, J; Roller-Lutz, Z

    2014-08-01

    Here we present the results of the first systematic analysis of the stable isotope composition of the karst hydrological systems in the Bay of Kvarner. Gaussian mixture modelling, time series analysis and autoregressive integrated moving average (ARIMA) modelling were applied using the stable isotope compositions of the karst groundwater. This study revealed that the recharge is dominated by winter precipitation, the dual-porosity system is dominated by baseflow, the hinterlands of the individual springs have different degrees of karstification and the springs within the Rječina River catchment have higher recharge elevations than the springs in the Bakar Bay catchment.

  6. Unprotected karst resources in western Iran: the environmental impacts of intensive agricultural pumping on the covered karstic aquifer, a case in Kermanshah province

    NASA Astrophysics Data System (ADS)

    Taheri, Kamal; Taheri, Milad; Parise, Mario

    2015-04-01

    Bare and covered karst areas, with developed karstic aquifers, cover 35 percent of the Kermanshah province in western Iran. These aquifers are the vital sources for drinking and agricultural water supplies. Over the past decade, intensive groundwater use (exploitation) for irrigation imposed a significant impact on the carbonate environments. The huge amount of groundwater over-exploitations has been carried out and still goes on by local farmers in the absence of appropriate governance monitoring control. Increasing in water demands, for more intense crop production, is an important driving force toward groundwater depletion in alluvial aquifers. Progressive groundwater over-exploitations from underlying carbonate rocks have led to dramatic drawdown in alluvial aquifers and deep karst water tables. Detecting new sources of groundwater extractions and prohibiting the karst water utilization for agricultural use could be the most effective strategy to manage the sustainability of covered karst aquifers. Anthropogenic pressures on covered karst aquifers have magnified the drought impacts and caused dryness of most of the karst springs and deep wells. In this study, the combination of geophysical and geological studies was used to estimate the most intensively exploited agricultural zones of Islam Abad plain in the southwestern Kermanshah province using GIS. The results show that in the past decade a great number of deep wells were drilled through the overburden alluvial aquifer and reached the deep karst water resources. However, the difficulties involved in monitoring deep wells in covered karst aquifer were the main cause of karst water depletion. Overexploitation from both alluvial and karst aquifers is the main reason for drying out the Arkawazi, Sharafshah, Gawrawani karst springs, and the karst drinking water wells 1, 3 and 5 of Islam Abad city. Karst spring landscape destructions, fresh water supply deficit for inhabitants, decreasing of tourism and

  7. Exploring the relationship between vegetation spectra and eco-geo-environmental conditions in karst region, Southwest China.

    PubMed

    Yue, Yuemin; Wang, Kelin; Zhang, Bing; Chen, Zhengchao; Jiao, Quanjun; Liu, Bo; Chen, Hongsong

    2010-01-01

    Remote sensing of local environmental conditions is not accessible if substrates are covered with vegetation. This study explored the relationship between vegetation spectra and karst eco-geo-environmental conditions. Hyperspectral remote sensing techniques showed that there were significant differences between spectral features of vegetation mainly distributed in karst and non-karst regions, and combination of 1,300- to 2,500-nm reflectance and 400- to 680-nm first-derivative spectra could delineate karst and non-karst vegetation groups. Canonical correspondence analysis (CCA) successfully assessed to what extent the variation of vegetation spectral features can be explained by associated eco-geo-environmental variables, and it was found that soil moisture and calcium carbonate contents had the most significant effects on vegetation spectral features in karst region. Our study indicates that vegetation spectra is tightly linked to eco-geo-environmental conditions and CCA is an effective means of studying the relationship between vegetation spectral features and eco-geo-environmental variables. Employing a combination of spectral and spatial analysis, it is anticipated that hyperspectral imagery can be used in interpreting or mapping eco-geo-environmental conditions covered with vegetation in karst region.

  8. A review of the potential and actual sources of pollution to groundwater in selected karst areas in Slovenia

    NASA Astrophysics Data System (ADS)

    Kovačič, G.; Ravbar, N.

    2005-02-01

    Slovenian karst areas extend over 43% of the country; limestones and dolomites of the Mesozoic era prevail. In Slovenia karst groundwater contributes up to 50% of the total drinking water supply. The quality of water is very high, despite the fact that it is extremely vulnerable to pollution. The present article is a study and a review of the potential and actual sources of pollution to the groundwater in the selected karst aquifers (the Kras, Velika planina and Snežnik plateaus), which differ in their natural characteristics. Unlike the other selected plateaus, the Kras plateau is inhabited. There are several settlements in the area and the industrial, agricultural and traffic activities carried out that represent a serious threat to the quality of karst groundwater. The Velika planina and Snežnik plateaus do not have permanent residents, however there are some serious hazards to the quality of the karst springs arising from sports, tourist, construction and farming activities, as well as from the traffic related to them. Despite relatively favourable conditions for protection, many important karst aquifers and springs are improperly protected in Slovenia. The reason is the lack of knowledge about sustainable water management in karst regions and the confusion in drinking water protection policy.

  9. Anthropogenic contaminants as tracers in an urbanizing karst aquifer

    NASA Astrophysics Data System (ADS)

    Mahler, Barbara; Massei, Nicolas

    2007-04-01

    Karst aquifers are uniquely vulnerable to contamination. In the Barton Springs segment of the karstic Edwards aquifer (Texas, U.S.A.), urban contaminants such as pesticides and volatile organic compounds frequently are detected in spring base flow. To determine whether contaminant concentrations change in response to storms, and if they therefore might act as tracers of focused recharge, samples were collected from Barton Springs at closely spaced intervals following three storms. Two herbicides (atrazine and simazine), two insecticides (carbaryl and diazinon), and a solvent (tetrachloroethene) described breakthrough curves over a 1-week period following one or more storms. The breakthrough curves were decomposed into two to five log-normal subcurves, which were interpreted as representing pulses of contaminants moving through the aquifer. Each subcurve could be used in the same way as an artificial tracer to determine travel time to and recovery at the spring. The contaminants have several advantages over artificial tracers: they represent the actual compounds of interest, they are injected essentially simultaneously at several points, and they are injected under those conditions when transport is of the most interest, i.e., following storms. The response of storm discharge, specific conductance, and contaminant loading at the spring depended on initial aquifer flow conditions, which varied from very low (spring discharge of 0.48 m 3/s) to high (spring discharge of 2.7 m 3/s): concentrations and recovery were the highest when initial aquifer flow conditions were low. This behavior provides information about aquifer structure and the influence of aquifer flow condition on transport properties.

  10. Anthropogenic contaminants as tracers in an urbanizing karst aquifer.

    PubMed

    Mahler, Barbara; Massei, Nicolas

    2007-04-01

    Karst aquifers are uniquely vulnerable to contamination. In the Barton Springs segment of the karstic Edwards aquifer (Texas, U.S.A.), urban contaminants such as pesticides and volatile organic compounds frequently are detected in spring base flow. To determine whether contaminant concentrations change in response to storms, and if they therefore might act as tracers of focused recharge, samples were collected from Barton Springs at closely spaced intervals following three storms. Two herbicides (atrazine and simazine), two insecticides (carbaryl and diazinon), and a solvent (tetrachloroethene) described breakthrough curves over a 1-week period following one or more storms. The breakthrough curves were decomposed into two to five log-normal subcurves, which were interpreted as representing pulses of contaminants moving through the aquifer. Each subcurve could be used in the same way as an artificial tracer to determine travel time to and recovery at the spring. The contaminants have several advantages over artificial tracers: they represent the actual compounds of interest, they are injected essentially simultaneously at several points, and they are injected under those conditions when transport is of the most interest, i.e., following storms. The response of storm discharge, specific conductance, and contaminant loading at the spring depended on initial aquifer flow conditions, which varied from very low (spring discharge of 0.48 m3/s) to high (spring discharge of 2.7 m3/s): concentrations and recovery were the highest when initial aquifer flow conditions were low. This behavior provides information about aquifer structure and the influence of aquifer flow condition on transport properties.

  11. Anthropogenic contaminants as tracers in an urbanizing karst aquifer

    USGS Publications Warehouse

    Mahler, B.; Massei, N.

    2007-01-01

    Karst aquifers are uniquely vulnerable to contamination. In the Barton Springs segment of the karstic Edwards aquifer (Texas, U.S.A.), urban contaminants such as pesticides and volatile organic compounds frequently are detected in spring base flow. To determine whether contaminant concentrations change in response to storms, and if they therefore might act as tracers of focused recharge, samples were collected from Barton Springs at closely spaced intervals following three storms. Two herbicides (atrazine and simazine), two insecticides (carbaryl and diazinon), and a solvent (tetrachloroethene) described breakthrough curves over a 1-week period following one or more storms. The breakthrough curves were decomposed into two to five log-normal subcurves, which were interpreted as representing pulses of contaminants moving through the aquifer. Each subcurve could be used in the same way as an artificial tracer to determine travel time to and recovery at the spring. The contaminants have several advantages over artificial tracers: they represent the actual compounds of interest, they are injected essentially simultaneously at several points, and they are injected under those conditions when transport is of the most interest, i.e., following storms. The response of storm discharge, specific conductance, and contaminant loading at the spring depended on initial aquifer flow conditions, which varied from very low (spring discharge of 0.48??m3/s) to high (spring discharge of 2.7??m3/s): concentrations and recovery were the highest when initial aquifer flow conditions were low. This behavior provides information about aquifer structure and the influence of aquifer flow condition on transport properties. ?? 2006 Elsevier B.V. All rights reserved.

  12. Flow Classification and Cave Discharge Characteristics in Unsaturated Karst Formation

    NASA Astrophysics Data System (ADS)

    Mariethoz, G.; Mahmud, K.; Baker, A.; Treble, P. C.

    2015-12-01

    In this study we utilize the spatial array of automated cave drip monitoring in two large chambers of the Golgotha Cave, SW Australia, developed in Quaternary aeolianite (dune limestone), with the aim of understanding infiltration water movement via the relationships between infiltration, stalactite morphology and groundwater recharge. Mahmud et al. (2015) used the Terrestrial LiDAR measurements to analyze stalactite morphology and to characterize possible flow locations in this cave. Here we identify the stalactites feeding the drip loggers and classify each as matrix (soda straw or icicle), fracture or combined-flow. These morphology-based classifications are compared with flow characteristics from the drip logger time series and the discharge from each stalactite is calculated. The total estimated discharge from each area is compared with infiltration estimates to better understand flow from the surface to the cave ceilings of the studied areas. The drip discharge data agrees with the morphology-based flow classification in terms of flow and geometrical characteristics of cave ceiling stalactites. No significant relationships were observed between the drip logger discharge, skewness and coefficient of variation with overburden thickness, due to the possibility of potential vadose-zone storage volume and increasing complexity of the karst architecture. However, these properties can be used to characterize different flow categories. A correlation matrix demonstrates that similar flow categories are positively correlated, implying significant influence of spatial distribution. The infiltration water comes from a larger surface area, suggesting that infiltration is being focused to the studied ceiling areas of each chamber. Most of the ceiling in the cave site is dry, suggesting the possibility of capillary effects with water moving around the cave rather than passing through it. Reference:Mahmud et al. (2015), Terrestrial Lidar Survey and Morphological Analysis to

  13. Submerged Humid Tropical Karst Landforms Observed By High-Resolution Multibeam Survey in Nagura Bay, Ishigaki Island, Southwestern Japan

    NASA Astrophysics Data System (ADS)

    Kan, H.; Urata, K.; Nagao, M.; Hori, N.; Fujita, K.; Yokoyama, Y.; Nakashima, Y.; Ohashi, T.; Goto, K.; Suzuki, A.

    2014-12-01

    Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the South Ryukyu Islands, Japan. This is the first description of submerged humid tropical karst using multibeam bathymetry. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results with a grid size of 1 m over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. We assume that Nagura Bay was a large karst basin in which older limestone remained submerged, thus preventing corrosion and the accumulation of reef sediments during periods of submersion, whereas the limestone outcropping on land was corroded during multiple interglacial and glacial periods. Based on our bathymetric result together with aerial photographs of the coastal area, we conclude that the submerged karst landscape has likely developed throughout the whole of Nagura Bay, covering an area of ~6 × 5 km. Accordingly, this area hosts the largest submerged karst in Japan. We also observed abundant coral communities during our SCUBA observations. The present marine conditions of Nagura Bay are characterized by low energy (calm sea) and low irradiance owing to the terrestrial influence. Such conditions have been emphasized by the presence of large undulating landforms, which cause decreases in wave intensity and irradiance with depth. These characteristics have acted to establish unique conditions compared to other coral reef areas in the Ryukyu Islands. It may play an important role in supporting the regional coral reef ecosystem.

  14. Crveno jezero - the biggest sinkhole in Dinaric Karst (Croatia)

    NASA Astrophysics Data System (ADS)

    Garasic, M.

    2012-04-01

    Crveno jezero is a karst phenomenon known throughout the world for its size and specific features. In the course of the 1950's, some hydrological measurements were made on the surface of the lake, including depth measurement at 39 points (academician M. Petrik and his associates). The information about the maximum depth of 254 meters actually originates from that research (PETRIK, 1960). This depth has been "attracting" geologists, hydrogeologists and speleologists for many years now. On numerous occasions, people descended to the surface of the lake but, in the period prior to speleohydrogeological research conducted in 1998, no attempt had been made to dive underwater and document the lake depth, nor to investigate by other methods the interior of the lake and give a scientifically documented representation of this karst phenomenon from the speleohydrogeological aspect (GARAŠIĆ, 2000; 2001). The Red Lake, located one kilometer to the west of Imotski, is the biggest of all lakes situated in the area (featuring 18 big or small dry or water-filled depressions) and this by both its visible (superficial) and invisible (submerged) portions. Its name originates from red rocks perched on cliffs extending to more than 250 meters in height. The lake color is dark blue, and it measures about 150 x 180 meters, depending on water level, i.e. on the time of the year. The easiest way to reach the lake (belay, descend and ascend with ropes) is to approach it from the east side. Here we have a vertical cliff about 60 meters in height, followed by 300 meters of a very steep soil creep zone, after which there is yet another vertical cliff of at least ten meters in height (depending on lake water level). In other words, a special descending technique must be used to access any point along the lake perimeter in summer months. Vertical and overhanging cliffs rising above the surface of the lake range from 160 to 250 meters in height. However, the depth of the lake is even more

  15. A mathematical model for simulating spring discharge and estimating sinkhole porosity in a karst watershed

    NASA Astrophysics Data System (ADS)

    Li, Guangquan; Field, Malcolm S.

    2014-03-01

    Documenting and understanding water balances in a karst watershed in which groundwater and surface water resources are strongly interconnected are important aspects for managing regional water resources. Assessing water balances in karst watersheds can be difficult, however, because karst watersheds are so very strongly affected by groundwater flows through solution conduits that are often connected to one or more sinkholes. In this paper we develop a mathematical model to approximate sinkhole porosity from discharge at a downstream spring. The model represents a combination of a traditional linear reservoir model with turbulent hydrodynamics in the solution conduit connecting the downstream spring with the upstream sinkhole, which allows for the simulation of spring discharges and estimation of sinkhole porosity. Noting that spring discharge is an integral of all aspects of water storage and flow, it is mainly dependent on the behavior of the karst aquifer as a whole and can be adequately simulated using the analytical model described in this paper. The model is advantageous in that it obviates the need for a sophisticated numerical model that is much more costly to calibrate and operate. The model is demonstrated using the St. Marks River Watershed in northwestern Florida.

  16. Microbial diversity and impact on carbonate geochemistry across a changing geochemical gradient in a karst aquifer

    PubMed Central

    Gray, Cassie J; Engel, Annette S

    2013-01-01

    Although microbes are known to influence karst (carbonate) aquifer ecosystem-level processes, comparatively little information is available regarding the diversity of microbial activities that could influence water quality and geological modification. To assess microbial diversity in the context of aquifer geochemistry, we coupled 16S rRNA Sanger sequencing and 454 tag pyrosequencing to in situ microcosm experiments from wells that cross the transition from fresh to saline and sulfidic water in the Edwards Aquifer of central Texas, one of the largest karst aquifers in the United States. The distribution of microbial groups across the transition zone correlated with dissolved oxygen and sulfide concentration, and significant variations in community composition were explained by local carbonate geochemistry, specifically calcium concentration and alkalinity. The waters were supersaturated with respect to prevalent aquifer minerals, calcite and dolomite, but in situ microcosm experiments containing these minerals revealed significant mass loss from dissolution when colonized by microbes. Despite differences in cell density on the experimental surfaces, carbonate loss was greater from freshwater wells than saline, sulfidic wells. However, as cell density increased, which was correlated to and controlled by local geochemistry, dissolution rates decreased. Surface colonization by metabolically active cells promotes dissolution by creating local disequilibria between bulk aquifer fluids and mineral surfaces, but this also controls rates of karst aquifer modification. These results expand our understanding of microbial diversity in karst aquifers and emphasize the importance of evaluating active microbial processes that could affect carbonate weathering in the subsurface. PMID:23151637

  17. Karst features detection and mapping using airphotos, DSMs and GIS techniques

    NASA Astrophysics Data System (ADS)

    Kakavas, M. P.; Nikolakopoulos, K. G.; Zagana, E.

    2015-10-01

    The aim of this work is to detect and qualify natural karst depressions in the Aitoloakarnania Prefecture, Western Greece, using remote sensing data in conjunction with the Geographical Information Systems - GIS. The study area is a part of the Ionian geotectonic zone, and its geological background consists of the Triassic Evaporates. The Triassic carbonate breccias where formed as a result of the tectonic and orogenetic setting of the external Hellenides and the diaper phenomena of the Triassic Evaporates. The landscape characterized by exokarst features closed depressions in the Triassic carbonate breccias. At the threshold of this study, an in situ observation was performed in order to identify dolines and swallow holes. The creation of sinkholes, in general, is based on the collapse of the surface layer due to chemical dissolution of carbonate rocks. In the current study airphotos stereopairs, DSMs and GIS were combined in order to detect and map the karst features. Thirty seven airphotos were imported in Leica Photogrammetry Suite and a stereo model of the study area was created. Then in 3D view possible karst features were detected and digitized. Those sites were verified during the in situ survey. ASTER GDEM, SRTM DEM, high resolution airphoto DSM created from the Greek Cadastral and a DEM from digitized contours from the 1/50,000 topographic were also evaluated in GIS environment for the automatic detection of the karst depressions. The results are presented in this study.

  18. Hydrology of autogenic percolation systems in some tropical karst outcrops, West Malaysia

    NASA Astrophysics Data System (ADS)

    Crowther, J.

    1983-01-01

    This paper reports on the flow regimes of underground seepages in three tower-karst outcrops and in the Setul Boundary Range, West Malaysia. Groundwater movement in the tower-karst hills, which comprise very pure, massive marbles, is confined to vertical and subvertical joints. Although flow is primarily diffuse and the discharges of the majority of seepages correlate most closely with rainfall in antecedent periods of 1-16 days or more, some stormflow occurs along conduits in the upper parts of these aquifers. Many of these conduits appear to peter out at depth into tight rock fractures, thereby forming funnel-shaped underground reservoirs which serve to moderate discharge variations. In contrast, the limestones of the Setul Boundary Range are less pure and retain much of their original bedding. The presence of near-horizontal bedding plane fractures favours lateral groundwater movement and the development of integrated drainage networks within the rock. Compared with the tower-karst caves, seepage rates are generally higher and more responsive to short-term variations in rainfall. The marked difference in topography between the tower-karst hills and the Setul Boundary Range is largely attributable to the contrasted geohydrological properties of the limestones.

  19. Hyporheic exchange in a karst conduit and sediment system - A laboratory analog study

    NASA Astrophysics Data System (ADS)

    Wu, Yuexia; Hunkeler, Daniel

    2013-09-01

    Karst conduits are often partly filled by clastic sediments. Flow through such sediments can have a strong impact on the fate of sediment-entrapped contaminants. In contrast to stream bed sediments, hyporheic flow in karst sediments has received little attention so far. For karst sediments, conduit bends could induce hyporheic flow, in addition to bedforms or obstacles. The main aim of this study was to investigate flow processes in a conduit-sediment system using a laboratory model resembling a siphon and numerical modeling. In the laboratory system, zones with forward and reserve flow occurred in the sediment due to the conduit bends. As demonstrated with sediment-source tracer test, entrapped solutes were generally flushed out more rapidly at a higher flow rate and steeper conduit angle. Numerical modeling assuming pressure continuity across the conduit-sediment interface reproduced the flow patterns and breakthrough curves (BTCs) well. Based on the model, the magnitude of hyporheic exchange is expected to increase linearly with the flow rate and was higher for a steeper conduit angle. However, the increase in flushing intensity was not evenly distributed throughout the sediments but occurred mainly adjacent to the conduit bends consistent with observations from tracer tests. This study confirms that conduit bends could have a strong influence on hyporheic flow in karst sediments.

  20. Comparison of a karst groundwater model with and without discrete conduit flow

    NASA Astrophysics Data System (ADS)

    Saller, Stephen P.; Ronayne, Michael J.; Long, Andrew J.

    2013-11-01

    Karst aquifers exhibit a dual flow system characterized by interacting conduit and matrix domains. This study evaluated the coupled continuum pipe-flow framework for modeling karst groundwater flow in the Madison aquifer of western South Dakota (USA). Coupled conduit and matrix flow was simulated within a regional finite-difference model over a 10-year transient period. An existing equivalent porous medium (EPM) model was modified to include major conduit networks whose locations were constrained by dye-tracing data and environmental tracer analysis. Model calibration data included measured hydraulic heads at observation wells and estimates of discharge at four karst springs. Relative to the EPM model, the match to observation well hydraulic heads was substantially improved with the addition of conduits. The inclusion of conduit flow allowed for a simpler hydraulic conductivity distribution in the matrix continuum. Two of the high-conductivity zones in the EPM model, which were required to indirectly simulate the effects of conduits, were eliminated from the new model. This work demonstrates the utility of the coupled continuum pipe-flow method and illustrates how karst aquifer model parameterization is dependent on the physical processes that are simulated.

  1. Factors Affecting Public-Supply Well Vulnerability in Two Karst Aquifers

    PubMed Central

    Musgrove, MaryLynn; Katz, Brian G; Fahlquist, Lynne S; Crandall, Christy A; Lindgren, Richard J

    2014-01-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearby monitoring wells and regional PSWs. Geochemistry results were integrated with age tracers, flow modeling, and depth-dependent data to refine aquifer conceptual models and to identify factors that affect contaminant movement to PSWs. The oxic Edwards aquifer is vertically well mixed at the selected PSW/wellfield, although regionally the aquifer is geochemically variable downdip. The mostly anoxic Upper Floridan aquifer is affected by denitrification and also is geochemically variable with depth. In spite of considerable differences in geology and hydrogeology, the two aquifers are similarly vulnerable to anthropogenic contamination. Vulnerability in studied PSWs in both aquifers is strongly influenced by rapid karst flowpaths and the dominance of young (<10 years) groundwater. Vulnerability was demonstrated by the frequent detection of similar constituents of concern in both aquifers (nitrate, atrazine, deethylatrazine, tetrachloroethene, and chloroform). Specific consideration of water-quality protection efforts, well construction and placement, and aquifer response times to land-use changes and contaminant loading are discussed, with implications for karst groundwater management. PMID:24841501

  2. Carbamazepine breakthrough as indicator for specific vulnerability of karst springs: application on the Jeita spring, Lebanon

    NASA Astrophysics Data System (ADS)

    Doummar, J.; Geyer, T.; Noedler, K.; Sauter, M.

    2014-12-01

    The pharmaceutical drug carbamazepine is considered an effective wastewater marker. The varying concentration of this drug was analyzed in a mature karst spring following a precipitation event. The results show that carbamazepine is an indicator of wastewater entering the system through a fast flow pathway, leading to an increase of the drug concentrations in spring water shortly after a strong rainfall event. The analysis of the breakthrough curve of carbamazepine along with the electrical conductivity signal and major ions chemograph allowed the development of a conceptual model for precipitation event-based flow and transport in the investigated karst system. Furthermore the amount of newly recharged water and the mass of carbamazepine reaching the aquifer system during the event could be estimated using a simple mixing approach. The distance between the karst spring and the potential carbamazepine source was estimated by the combination of results from artificial tracer tests and the carbamazepine breakthrough curve. The assessment of spring responses to precipitation event using persistent drugs like carbamazepine helps assess the effect of waste water contamination at a spring and gives therefore insights to the specific vulnerability of a karst spring.

  3. Applications of GIS and database technologies to manage a Karst Feature Database

    USGS Publications Warehouse

    Gao, Y.; Tipping, R.G.; Alexander, E.C.

    2006-01-01

    This paper describes the management of a Karst Feature Database (KFD) in Minnesota. Two sets of applications in both GIS and Database Management System (DBMS) have been developed for the KFD of Minnesota. These applications were used to manage and to enhance the usability of the KFD. Structured Query Language (SQL) was used to manipulate transactions of the database and to facilitate the functionality of the user interfaces. The Database Administrator (DBA) authorized users with different access permissions to enhance the security of the database. Database consistency and recovery are accomplished by creating data logs and maintaining backups on a regular basis. The working database provides guidelines and management tools for future studies of karst features in Minnesota. The methodology of designing this DBMS is applicable to develop GIS-based databases to analyze and manage geomorphic and hydrologic datasets at both regional and local scales. The short-term goal of this research is to develop a regional KFD for the Upper Mississippi Valley Karst and the long-term goal is to expand this database to manage and study karst features at national and global scales.

  4. Comparison of Recharge Estimation Methods During a Wet Period in a Karst Aquifer.

    PubMed

    Guardiola-Albert, Carolina; Martos-Rosillo, Sergio; Pardo-Igúzquiza, Eulogio; Durán Valsero, Juan José; Pedrera, Antonio; Jiménez-Gavilán, Pablo; Liñán Baena, Cristina

    2015-01-01

    Management of water resources, implying their appropriate protection, calls for a sound evaluation of recharge. Such assessment is very complex in karst aquifers. Most methods are developed for application to detrital aquifers, without taking into account the extraordinary heterogeneity of porosity and permeability of karst systems. It is commonly recommended to estimate recharge using multiple methods; however, differences inherent to the diverse methods make it difficult to clarify the accuracy of each result. In this study, recharge was estimated in a karst aquifer working in a natural regime, in a Mediterranean-type climate, in the western part of the Sierra de las Nieves (southern Spain). Mediterranean climate regions are characterized by high inter-annual rainfall variability featuring long dry periods and short intense wet periods, the latter constituting the most important contribution to aquifer water input. This paper aims to identify the methods that provide the most plausible range of recharge rate during wet periods. Six methods were tested: the classical method of Thornthwaite-Mather, the Visual Balan code, the chloride balance method, and spatially distributed methods such as APLIS, a novel spatiotemporal estimation of recharge, and ZOODRM. The results help determine valid methods for application in the rest of the unit of study and in similar karst aquifers.

  5. Mechanism and prevention of karst collapse near mine areas in China

    SciTech Connect

    Xu Weiguo; Zhao Guirong )

    1988-08-01

    The authors of this article have described essential conditions and environmental forms of collapse in covered karst mine areas in China as well as external causes such as drastic lowering of the ground water surface. The authors present a theory of suction action causing collapse, and an air-charging method to prevent the collapse. The result obtained by this method is favorable.

  6. Transport and Attenuation of Particles of Different Density and Surface Charge: A Karst Aquifer Field Study.

    PubMed

    Schiperski, Ferry; Zirlewagen, Johannes; Scheytt, Traugott

    2016-08-01

    Although karst aquifers are far more susceptible to contamination than porous aquifers, with the transport of particulate matter being an important factor, little is known about the attenuation of solutes within karst aquifers and even less about the attenuation of particulate matter. These in situ investigations have therefore aimed to systematically identify the processes that influence the transport and attenuation of particles within a karst aquifer through multitracer testing, using four different types of 1 μm fluorescent particles and the fluorescent dye uranine. Each of the types of particles used were detected at the observed spring, which drains the investigated aquifer. However, the transport behavior varied significantly between the various particles and the uranine dye, with the breakthrough of particles occurring slightly earlier than that of uranine. Attenuation was determined from the tracer recovery and attributed to filtration processes. These processes were affected by the hydrophobicity and surface charge of the particles. Carboxylated polystyrene particles with a density and surface charge comparable to pathogenic microorganisms were found to be mobile in groundwater over a distance of about 3 km. No attenuation was observed for plain silica particles. Particles with these characteristics thus pose a major threat to karst spring water as they might occur as contaminants themselves or facilitate the transport of other contaminants.

  7. Comparison of a karst groundwater model with and without discrete conduit flow

    USGS Publications Warehouse

    Saller, Stephen P.; Ronayne, Michael J.; Long, Andrew J.

    2013-01-01

    Karst aquifers exhibit a dual flow system characterized by interacting conduit and matrix domains. This study evaluated the coupled continuum pipe-flow framework for modeling karst groundwater flow in the Madison aquifer of western South Dakota (USA). Coupled conduit and matrix flow was simulated within a regional finite-difference model over a 10-year transient period. An existing equivalent porous medium (EPM) model was modified to include major conduit networks whose locations were constrained by dye-tracing data and environmental tracer analysis. Model calibration data included measured hydraulic heads at observation wells and estimates of discharge at four karst springs. Relative to the EPM model, the match to observation well hydraulic heads was substantially improved with the addition of conduits. The inclusion of conduit flow allowed for a simpler hydraulic conductivity distribution in the matrix continuum. Two of the high-conductivity zones in the EPM model, which were required to indirectly simulate the effects of conduits, were eliminated from the new model. This work demonstrates the utility of the coupled continuum pipe-flow method and illustrates how karst aquifer model parameterization is dependent on the physical processes that are simulated.

  8. Factors affecting public-supply well vulnerability in two karst aquifers

    USGS Publications Warehouse

    Musgrove, MaryLynn; Katz, Brian G.; Fahlquist, Lynne S.; Crandall, Christy A.; Lindgren, Richard J.

    2014-01-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearby monitoring wells and regional PSWs. Geochemistry results were integrated with age tracers, flow modeling, and depth-dependent data to refine aquifer conceptual models and to identify factors that affect contaminant movement to PSWs. The oxic Edwards aquifer is vertically well mixed at the selected PSW/wellfield, although regionally the aquifer is geochemically variable downdip. The mostly anoxic Upper Floridan aquifer is affected by denitrification and also is geochemically variable with depth. In spite of considerable differences in geology and hydrogeology, the two aquifers are similarly vulnerable to anthropogenic contamination. Vulnerability in studied PSWs in both aquifers is strongly influenced by rapid karst flowpaths and the dominance of young (<10 years) groundwater. Vulnerability was demonstrated by the frequent detection of similar constituents of concern in both aquifers (nitrate, atrazine, deethylatrazine, tetrachloroethene, and chloroform). Specific consideration of water-quality protection efforts, well construction and placement, and aquifer response times to land-use changes and contaminant loading are discussed, with implications for karst groundwater management.

  9. Going Underground: A Field Investigation and Lab Activity on Karst Topography and Water Systems

    ERIC Educational Resources Information Center

    O'Dell, Gary; Gonzalez-Espada, Wilson

    2011-01-01

    Students learn science best with activities that mirror the way scientists work. This article describes how geologists investigate groundwater flow systems in areas of karst topography--geologic formations shaped by dissolving bedrock--and provides a way for students to replicate this research. Students also use electric current to model water…

  10. Advanced karst hydrological and contaminant monitoring techniques for real-time and high resolution applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In telogenetic and soil-mantled karst aquifers, the movement of autogenic recharge through the epikarstic zone and into the regional aquifer can be a complex process and have implications for flooding, groundwater contamination, and other difficult to capture processes. Recent advances in instrument...

  11. Tracing fecal pollution sources in karst groundwater by Bacteroidales genetic biomarkers, bacterial indicators, and environmental variables.

    PubMed

    Zhang, Ya; Kelly, Walton R; Panno, Samuel V; Liu, Wen-Tso

    2014-08-15

    Fecal contamination in Midwestern karst regions was evaluated by simultaneously measuring traditional bacterial indicators (coliforms and Escherichia coli), Bacteroidales-based biomarkers, and environmental variables. Water samples from springs and wells were collected from karst regions in Illinois (IL), Wisconsin (WI), Kentucky (KY), and Missouri (MO). Quantitative PCR (Q-PCR) with seven primer sets targeting different members of Bacteroidales was used to determine the origin of fecal contamination (i.e., from human waste, livestock waste, or both). Most samples were contaminated by both human and animal waste, with a few samples showing pollution solely by one or the other. Spring water tended to have higher levels of contamination than well water, and higher concentrations of fecal biomarkers were detected in urban springs compared to rural spring systems. However, there were discrepancies on contamination profile determined by Bacteroidales-based biomarkers and by traditional bacterial indicators. Among all the environmental parameters examined, E. coli, sulfate, total dissolved solids (TDS), and silicon were significantly correlated (p<0.05) with the level of Bacteroidales-based fecal indicators. A rapid screening method using total nitrogen (TN) and chloride (Cl(-)) concentrations to determine fecal contamination was shown to be effective and correlated well with Bacteroidales-based MST. The results suggest that human and livestock feces co-contaminated a large portion of karst groundwater systems in Midwestern regions, and the inclusion of traditional bacterial indicators, environmental variables, and Bacteroidales-based MST is an effective approach for identifying fecal contamination in karst regions.

  12. Karst-controlled reservoir heterogeneity in Ellenburger group carbonates of west Texas: Reply

    SciTech Connect

    Kerans, C. )

    1990-07-01

    A reply to a comment made on Kerans' paper (AAGP Bull. 1988) by S.J. Mazzullo is presented. The author takes exception that Mazzullo's contention that he left out important types of hydrocarbon reservoirs in the Permian basin of west Texas and points out that his original intention was to model karst-controlled reservoir rocks only.

  13. Microbial diversity and impact on carbonate geochemistry across a changing geochemical gradient in a karst aquifer.

    PubMed

    Gray, Cassie J; Engel, Annette S

    2013-02-01

    Although microbes are known to influence karst (carbonate) aquifer ecosystem-level processes, comparatively little information is available regarding the diversity of microbial activities that could influence water quality and geological modification. To assess microbial diversity in the context of aquifer geochemistry, we coupled 16S rRNA Sanger sequencing and 454 tag pyrosequencing to in situ microcosm experiments from wells that cross the transition from fresh to saline and sulfidic water in the Edwards Aquifer of central Texas, one of the largest karst aquifers in the United States. The distribution of microbial groups across the transition zone correlated with dissolved oxygen and sulfide concentration, and significant variations in community composition were explained by local carbonate geochemistry, specifically calcium concentration and alkalinity. The waters were supersaturated with respect to prevalent aquifer minerals, calcite and dolomite, but in situ microcosm experiments containing these minerals revealed significant mass loss from dissolution when colonized by microbes. Despite differences in cell density on the experimental surfaces, carbonate loss was greater from freshwater wells than saline, sulfidic wells. However, as cell density increased, which was correlated to and controlled by local geochemistry, dissolution rates decreased. Surface colonization by metabolically active cells promotes dissolution by creating local disequilibria between bulk aquifer fluids and mineral surfaces, but this also controls rates of karst aquifer modification. These results expand our understanding of microbial diversity in karst aquifers and emphasize the importance of evaluating active microbial processes that could affect carbonate weathering in the subsurface.

  14. Factors affecting public-supply well vulnerability in two karst aquifers.

    PubMed

    Musgrove, MaryLynn; Katz, Brian G; Fahlquist, Lynne S; Crandall, Christy A; Lindgren, Richard J

    2014-09-01

    Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geochemistry of samples from a selected PSW or wellfield in each aquifer was compared with that from nearby monitoring wells and regional PSWs. Geochemistry results were integrated with age tracers, flow modeling, and depth-dependent data to refine aquifer conceptual models and to identify factors that affect contaminant movement to PSWs. The oxic Edwards aquifer is vertically well mixed at the selected PSW/wellfield, although regionally the aquifer is geochemically variable downdip. The mostly anoxic Upper Floridan aquifer is affected by denitrification and also is geochemically variable with depth. In spite of considerable differences in geology and hydrogeology, the two aquifers are similarly vulnerable to anthropogenic contamination. Vulnerability in studied PSWs in both aquifers is strongly influenced by rapid karst flowpaths and the dominance of young (<10 years) groundwater. Vulnerability was demonstrated by the frequent detection of similar constituents of concern in both aquifers (nitrate, atrazine, deethylatrazine, tetrachloroethene, and chloroform). Specific consideration of water-quality protection efforts, well construction and placement, and aquifer response times to land-use changes and contaminant loading are discussed, with implications for karst groundwater management.

  15. Coarse fragments affects soil properties in a mantled-karst landscape of the Ozark Highlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper investigates the effect of rock fragments on soil physical hydraulic properties within the mantled karst landscapes of the Savoy Experimental Watershed (SEW), a setting typical of much of the Ozark Plateaus. Water resources in these settings are highly susceptible to contamination. As a r...

  16. Prediction and assessment of the disturbances of the coal mining in Kailuan to karst groundwater system

    NASA Astrophysics Data System (ADS)

    Sun, Wenjie; Wu, Qiang; Liu, Honglei; Jiao, Jian

    Coal resources and water resources play an essential and strategic role in the development of China's social and economic development, being the priority for China's medium and long technological development. As the mining of the coal extraction is increasingly deep, the mine water inrush of high-pressure confined karst water becomes much more a problem. This paper carried out research on the hundred-year old Kailuan coal mine's karst groundwater system. With the help of advanced Visual Modflow software and numerical simulation method, the paper assessed the flow field of karst water area under large-scale exploitation. It also predicted the evolution ofgroundwaterflow field under different mining schemes of Kailuan Corp. The result shows that two cones of depression are formed in the karst flow field of Zhaogezhuang mining area and Tangshan mining area, and the water levels in two cone centers are -270 m and -31 m respectively, and the groundwater generally flows from the northeast to the southwest. Given some potential closed mines in the future, the mine discharge will decrease and the water level of Ordovician limestone will increase slightly. Conversely, given increase of coal yield, the mine drainage will increase, falling depression cone of Ordovician limestone flow field will enlarge. And in Tangshan's urban district, central water level of the depression cone will move slightly towards north due to pumping of a few mines in the north.

  17. Transport and Attenuation of Particles of Different Density and Surface Charge: A Karst Aquifer Field Study.

    PubMed

    Schiperski, Ferry; Zirlewagen, Johannes; Scheytt, Traugott

    2016-08-01

    Although karst aquifers are far more susceptible to contamination than porous aquifers, with the transport of particulate matter being an important factor, little is known about the attenuation of solutes within karst aquifers and even less about the attenuation of particulate matter. These in situ investigations have therefore aimed to systematically identify the processes that influence the transport and attenuation of particles within a karst aquifer through multitracer testing, using four different types of 1 μm fluorescent particles and the fluorescent dye uranine. Each of the types of particles used were detected at the observed spring, which drains the investigated aquifer. However, the transport behavior varied significantly between the various particles and the uranine dye, with the breakthrough of particles occurring slightly earlier than that of uranine. Attenuation was determined from the tracer recovery and attributed to filtration processes. These processes were affected by the hydrophobicity and surface charge of the particles. Carboxylated polystyrene particles with a density and surface charge comparable to pathogenic microorganisms were found to be mobile in groundwater over a distance of about 3 km. No attenuation was observed for plain silica particles. Particles with these characteristics thus pose a major threat to karst spring water as they might occur as contaminants themselves or facilitate the transport of other contaminants. PMID:27348254

  18. Delineating small karst watersheds based on digital elevation model and eco-hydrogeological principles

    NASA Astrophysics Data System (ADS)

    Jie Luo, Guang; Jie Wang, Shi; Bai, Xiao Yong; Liu, Xiu Ming; Cheng, An Yun

    2016-03-01

    Dominated by specific eco-hydrogeological backgrounds, a small watershed delineated by using the traditional method is always inauthentic in karst regions because it cannot accurately reflect the eco-hydrological process of the dual structure of the surface and subsurface. This study proposes a new method for the delineation of small watersheds based on digital elevation models (DEMs) and eco-hydrogeological principles in karst regions. This method is applied to one section of the tributary area (Sancha River) of the Yangtze River in China. By comparing the quantity, shape, superimposition, and characteristics of the internal hydrological process of a small watershed extracted by using the digital elevation model with that extracted by using the proposed method of this study, we conclude that the small karst watersheds extracted by the new method accurately reflect the hydrological process of the river basin. Furthermore, we propose that the minimum unit of the river basin in karst regions should be the watershed, whose exit is the corrosion and corrasion baselevel and a further division of watershed may cause a significant inconsistency with the true eco-hydrological process.

  19. Investigating relationships between rainfall and karst-spring discharge by higher-order partial correlation functions

    NASA Astrophysics Data System (ADS)

    Jukić, Damir; Denić-Jukić, Vesna

    2015-11-01

    Time series of rainfall and karst-spring discharge are influenced by various space-time-variant processes involved in the transfer of water in hydrological cycle. The effects of these processes can be exhibited in auto-correlation and cross-correlation functions. Consequently, ambiguities with respect to the effects encoded in the correlation functions exist. To solve this problem, a new statistical method for investigating relationships between rainfall and karst-spring discharge is proposed. The method is based on the determination and analysis of higher-order partial correlation functions and their spectral representations. The study area is the catchment of the Jadro Spring in Croatia. The analyzed daily time series are the air temperature, relative humidity, spring discharge, and rainfall at seven rain-gauges over a period of 19 years, from 1995 to 2013. The application results show that the effects of spatial and temporal variations of hydrological time series and the space-time-variant behaviours of the karst system can be separated from the correlation functions. Specifically, the effect of evapotranspiration can be separated to obtain the forms of correlation functions that represent the hydrogeological characteristics of the karst system. Using the proposed method, it is also possible to separate the effects of the process of groundwater recharge that occurs in neighbouring parts of a catchment to identify the specific contribution of each part of the catchment to the karst-spring discharge. The main quantitative results obtained for the Jadro Spring show that the quick-flow duration is 14 days, the intermediate-flow duration is 80 days, and the pure base flow starts after 80 days. The base flow consists of an inter-catchment groundwater flow. The system memory of the spring is 80 days. The presented results indicate the far-reaching applicability of the proposed method in the analyses of relationships between rainfall and karst-spring discharge; e

  20. Hydrogeological studies in high mountains karst environment: the example of Picos de Europa (Spain)

    NASA Astrophysics Data System (ADS)

    Meléndez, Mónica; Ballesteros, Daniel; Jiménez-Sanchez, Montserrat; García-Sansegundo, Joaquín

    2015-04-01

    Karst aquifers are very vulnerable to contamination due their high infiltration coefficient, elevated hydraulic conductivity, high speed of circulation, and very low self-purification capacities. The functioning of that type of aquifer is quite complicated by the high heterogeneity and anisotropy of the karst and the presence of three different types of porosity. It is necessary to understand the functioning of a karst aquifer in order to protect and manage them properly. Therefore, it is necessary to develop working methods to establish the aquifer hydrodynamics, especially in high mountain areas with many methodological constrains (e. g. difficulty to access). The Picos de Europa karst aquifer, located in theNational Park of Picos de Europa (North Spain), presents a high environmental, geomorphological and hydrogeological value; it is included in the "Spanish geological contexts with global relevance" by the Law of Natural Heritage and Biodiversity of Spain, being considered as a Global Geosite by the Geological and Mining Institute of Spain. In addition, the karst massif is included in several figures of environmental protection, both at global and national levels. Hydrogeological and geomorphological research is developed together in this area under the GEOCAVE project (MAGRAMA-580/12 OAPN) and the "Investigación hidrogeológica en las masas de agua subterránea 012.014 Picos de Europa-Panes y 012.018 Alto Deva-Alto Cares. (IGME-73.3.00.41.00/2013)". The aim of this study is to characterize the hydrodynamics of the karst aquifer, considering the snow as an important component of the aquifer recharge. The proposed methodology includes the installation of an integrated pressure sensor and data logger for level and temperature measurement in two karst spring related to two groundwater bodies (GWB) with 86 and 14 km2 extension. The store of data to regular intervals with punctual values of discharge measures has provided, at least, an annual series of data in

  1. Geomorphometric correlations of vegetation cover properties and topographic karst features based on high-resolution LiDAR DTM of Aggtelek Karst, NE Hungary

    NASA Astrophysics Data System (ADS)

    Székely, Balázs; Telbisz, Tamás; Koma, Zsófia; Kelemen, Kristóf; Szmorad, Ferenc; Deák, Márton; Látos, Tamás; Standovár, Tibor

    2015-04-01

    Topography and lithology are two major factors influencing the vegetation cover, its mosaic pattern and lateral transitions. In karstic areas the topography has a high diversity, microtopographic landforms influence the local ecological setting, vegetation structure. Presence of sinkholes of various sizes and geometric arrangements causes rapid lateral variation of the slope, aspect patterns as well as highly modify the soil water balance in time and space. These diversity of factors defines a mosaicked habitat pattern for vegetation assemblages. The World Heritage Site Aggtelek Karst/Slovakian Karst Caves has characteristic natural and environmental properties concerning the geomorphological as well as the ecological values. In order to be able to study the topographic influence on the ecological setting, a high-resolution digital terrain model (DTM) and digital surface model (DSM) have been derived from airborne laser scanning data depicting the karstic micro- and macrotopographic Landscape elements and the envelope surface of the canopy. Additional vegetation parameters like closure and average height have been derived from a normalized digital surface model (nDSM). Extensive mapping of vegetation properties has been carried out: centered on points of a grid array several vegetation-specific data - including composition and structure of tree and shrub layers, herbacesous vegetation and tree regeneration - have been acquired. Various classification patterns - based on trees pecies composition, vertical vegetation structure - have been derived from this data set. The comparison of the vegetation classification data and the geomorphometric DTM derivatives yielded interesting results. Certain vegetation characteristics often correlate with the geomorphometric properties. We interpret this similarity as sensitivity of vegetion to fine-scale variations in geomorphic properties like aspect, illumination conditions and soil properties. However, in many cases the

  2. Research about the Control of Geological Structure on Karst Groundwater system in Zhangfang, Beijing,China.

    NASA Astrophysics Data System (ADS)

    Qiao, X.

    2015-12-01

    Carbonate formations are intensively distributed throughout Zhangfang, fangshan, in West Mountain area in Beijing. Karst groundwater exits among the geological fracture network which is characterized by the different arrangements and levels in different types of fracture networks and structures. The influence of the tectonic environment on the dynamic change rule and the enrichment regulation of karst system is significant for the exploitation and protection of karst groundwater resources. From the control function of fault and fracture point of view, based on the developmental and distribution pattern of multi-episodic tectonism, this study analyzed fractures in the three-fold structural units characterized by NE-NW and NS trends and discussed the influence of multi-episodic tectonism on the groundwater flow system and rich water zones. The results showed that the geological fracture underwent two episodes of tectonism, thrusting nappe in the Jurassic and extension in the Cretaceous. The overprint of two episodes resulted in a number of faults with high hydraulic conductivity, which serve as conduits. The superiority joints groups are in the NE and NW directions, with conjugated characteristics. The high-angle or vertical dips directly benefit infiltration. The fractures in the intersection areas have formed groundwater runoff channels and strong space, controlling water-rich zones such as Baidai, Ganchi-Changgou and Gaozhuang-Shiwo. Magmatic rock and the aquiclude also contribute to the rich water zones and the location of springs, all of which have important significance for water supply. Keywords: system of Karst groundwater, geological structure, fracture network, hydrogeological flow field, Zhangfang karst area

  3. Mobilisation or dilution? Nitrate response of karst springs to high rainfall events

    NASA Astrophysics Data System (ADS)

    Huebsch, M.; Fenton, O.; Horan, B.; Hennessy, D.; Richards, K. G.; Jordan, P.; Goldscheider, N.; Butscher, C.; Blum, P.

    2014-11-01

    Nitrate (NO3-) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e. rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in South Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and on the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on the high

  4. Demographic pressure over the Environmental Protected Area of the Lagoa Santa Karst, Minas Gerais State, Brazil

    NASA Astrophysics Data System (ADS)

    Travassos, L. E. P.

    2009-04-01

    The State of Minas Gerais, Brazil, is approximately 586.528 km2. From this total, it is believed that about 29,000 km2(Piló 1997; 1999) are composed by carbonatic rocks. With a total of 853 municipalities and some evident environmental problems, the biggest problem is the proper final waste disposal as noticed by Travassos et al (2008). This work is intended to demonstrate the potential degradation of karst scenarios due to the increasing urbanization in the so called "North Vector". There are two State Parks and six other Conservation Units in this region. Historically the cities near this region have been used as dormitory towns. Further north, various ranches, country houses for the weekend and rural hostels are set on karst terrains. The municipalities of Vespasiano, Pedro Leopoldo, Confins, Lagoa Santa, Matozinhos, Funilândia and Prudente de Morais are within the 360 km2-large Environmental Protected Area of the Lagoa Santa Karst. All these municipalities have been facing demographic growth and consequently generate the anthropogenic pressure over the karst. Up to the date on which this abstract was written, the Decree n˚ 6640/2008, signed by the Brazilian government, is in effect. It substituted the previous one, Decree n˚ 99556/1990, which protected the Brazilian speleological heritage. According to the new Decree, now there are no warranties that caves will be protected against infra-structure constructions and mining companies. Besides, it also establishes relevance criteria that point out which caves which can be destroyed without any compensation at all. Certainly the speleological community is already mobilized against this new Decree. Keywords: karst, endokarst, exokarst, Cordisburgo region, Minas Gerais, Brazil.

  5. The Tony Grove Karst Region in Northern Utah: From Cave Sediments to Fluvial Geomorphology

    NASA Astrophysics Data System (ADS)

    Smith, H. D.

    2013-12-01

    The Tony Grove lake area is a dolomitic karst region in the Bear River Range of the Middle Rocky Mountain Province (Hintze 1973, Wilson 1976). The 5 km study area (Figure 1) is strewn with boulders and consists of a combination of subsurface dissolution caves underlying the highly-eroded karst surface reminiscent of past glaciation. Traces of the dynamic mountain structure can be seen in faults, fractures, and folds with the largest being the Logan Syncline (Wilson, 1976) formed during the Sevier Orogeny. The Tony Grove area stratigraphy is dominated by the Ordovician (505 MYR) Fish Haven dolomite and Silurian (438 MYR) Laketown dolomite units topped with some Devonian (406 MYR) aged inter-bedded quartzite, shale, and dolostone from the Water Canyon Formation (Morgan 1992, Spangler 2001). The 5 km study area contains over 90 karst features formed through vadose water flow due to the alpine proximity. The development and exhumation of these features have been greatly influenced over time by plate tectonics and water. We investigate cave formation and sediments as an indicator of past water flow and watershed dynamics. Figure 1. Site location of the Tony Grove lake area including an image of the karst terrain and geologic map showing the Logan Peak Syncline. The area is home to about 90 karst features including both do lines and caves. Figure 2. The cave sediments in this image of Thundershower Cave in the Tony Grove lake area show the flow pattern and a step and pool channel morphology with a side channel formed to the right during times of higher flow.

  6. Mobilisation or dilution? Nitrate response of karst springs to high rainfall events

    NASA Astrophysics Data System (ADS)

    Huebsch, M.; Fenton, O.; Horan, B.; Hennessy, D.; Richards, K. G.; Jordan, P.; Goldscheider, N.; Butscher, C.; Blum, P.

    2014-04-01

    Nitrate (NO3-) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e., rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in south Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on high resolution

  7. The Tony Grove Karst Region in Northern Utah: From Cave Sediments to Fluvial Geomorphology

    NASA Astrophysics Data System (ADS)

    Smith, H. D.

    2012-12-01

    The Tony Grove lake area is a dolomitic karst region in the Bear River Range of the Middle Rocky Mountain Province (Hintze, 1973; Wilson, 1976). Figure 1. The 5 km study area is strewn with boulders and consists of a combination of subsurface dissolution caves underlying the highly-eroded karst surface remnancent of past glaciation. Traces of the dynamic mountain structure can be seen in faults, fractures, and folds with the largest being the Logan Syncline (Wilson, 1976) formed during the Sevier Orogeny. The Tony Grove area stratigraphy is dominated by the Ordovician (505 MYR) Fish Haven dolomite and Silurian (438 MYR) Laketown dolomite units topped with some Devonian (406 MYR) aged inter-bedded quartzite, shale, and dolostone from the Water Canyon Formation (Morgan 1992, Spangler 2001). The 5 km study area contains over 90 karst features formed through vadose water flow due to the alpine proximity. The development and exhumation of these features have been greatly influenced over time by plate tectonics and water. We investigate cave formation and sediments as an indicator of past water flow and watershed dynamics (Figure 2). Figure 1. Site location of the Tony Grove Lake Area including an image of the karst terrain and geologic map showing the Logan Peak Syncline. The area is home to about 90 karst features inculding both dolines and caves. Figure 2. The cave sediments in this image of Thundershower Cave in the Tony Grove Lake Area show the flow pattern and a step and pool channel morphology with a side channel formed to the right during times of higher flow.

  8. [Distribution of 137Cs and relative influencing factors on typical karst sloping land].

    PubMed

    Zhang, Xiao-Nan; Wang, Ke-Lin; Zhang, Wei; Chen, Hong-Song; He, Xun-Yang; Zhang, Xin-Bao

    2009-11-01

    Based on the field survey and the analysis of a large number of soil samples, the distribution of 137 Cs and its influencing factors were studied using 137 Cs tracer technology on typical karst sloping land. The results indicate that the distribution of 137 Cs in soil profile in karst areas show the similar characteristics as that in non-karst areas, fitted an exponential pattern in forest soils and a uniform pattern in cultivated soils. In the sinkhole points in karst areas, 137 Cs exists in deep soil layers and its specific activity vary from 1.7 to 3.3 Bq/kg in soil layers above 45cm, suggesting the existing soil around karst sinkhole is mainly formed by the accumulation of erosion materials. The 137 Cs specific activity in the soil from two rock cracks are 16.8 Bq/kg and 37.6 Bq/kg respectively, which are much higher than that in the soil around the rock, this phenomenon indicates that bare rock is an important influencing factor for 137 Cs spatial movement. With the increment of altitude, the 137 Cs area activity exhibits an irregular fluctuation and evident spatial heterogeneity. On the forest land, the 137 Cs area activities which range from 299.4 to 1 592.6 Bq/m2 are highly positively correlated with the slope gradient and positively correlated with the altitude; while on the cultivated land, the 137 Cs area activities which range from 115.8 to 1478.6 Bq/m2 are negatively correlated with the slope gradient but negatively correlated with the altitude. Topography, geomorphology and human disturbance intensity are the key factors influencing 137 Cs spatial distribution.

  9. A new species of karst forest Bent-toed Gecko (genus Cyrtodactylus Gray) not yet threatened by foreign cement companies and a summary of Peninsular Malaysia's endemic karst forest herpetofauna and the need for its conservation.

    PubMed

    Grismer, L Lee; Wood, P L Jr; Anuar, Shahrul; Davis, H R; Cobos, A J; Murdoch, M L

    2016-01-01

    A new species of Bent-toed Gecko, Cyrtodactylus gunungsenyumensis sp. nov. of the sworderi complex, is described from Hutan Lipur Gunung Senyum, Pahang, Peninsular Malaysia and is differentiated from all other species in the sworderi complex by having a unique combination of characters including a maximum SVL of 74.7 mm; low, rounded, weakly keeled, body tubercles; 34-40 paravertebral tubercles; weak ventrolateral body fold lacking tubercles; 38-41 ventral scales; an abrupt transition between the posterior and ventral femoral scales; 20-23 subdigital lamellae on the fourth toe; enlarged femoral scales; no femoral or precloacal pores; no precloacal groove; wide caudal bands; and an evenly banded dorsal pattern. Cyrtodactylus gunungsenyumensis sp. nov. is a scansorial, karst forest-adapted specialist endemic to the karst ecosystem surrounding Gunung Senyum and occurs on the vertical walls of the limestone towers as well as the branches, trunks, and leaves of the vegetation in the associated karst forest. Cyrtodactylus gunungsenyumensis sp. nov. is the seventh species of karst forest-adapted Cyrtodactylus and the sixteenth endemic species of karst ecosystem reptile discovered in Peninsular Malaysia in the last seven years from only 12 different karst forests. This is a clear indication that many species remain to be discovered in the approximately 558 isolated karst ecosystems in Peninsular Malaysia not yet surveyed. These data continue to underscore the importance of karst ecosystems as reservoirs of biodiversity and microendemism and that they constitute an important component of Peninsular Malaysia's natural heritage and should be protected from the quarrying interests of foreign industrial companies. PMID:27395475

  10. A new species of karst forest Bent-toed Gecko (genus Cyrtodactylus Gray) not yet threatened by foreign cement companies and a summary of Peninsular Malaysia's endemic karst forest herpetofauna and the need for its conservation.

    PubMed

    Grismer, L Lee; Wood, P L Jr; Anuar, Shahrul; Davis, H R; Cobos, A J; Murdoch, M L

    2016-01-04

    A new species of Bent-toed Gecko, Cyrtodactylus gunungsenyumensis sp. nov. of the sworderi complex, is described from Hutan Lipur Gunung Senyum, Pahang, Peninsular Malaysia and is differentiated from all other species in the sworderi complex by having a unique combination of characters including a maximum SVL of 74.7 mm; low, rounded, weakly keeled, body tubercles; 34-40 paravertebral tubercles; weak ventrolateral body fold lacking tubercles; 38-41 ventral scales; an abrupt transition between the posterior and ventral femoral scales; 20-23 subdigital lamellae on the fourth toe; enlarged femoral scales; no femoral or precloacal pores; no precloacal groove; wide caudal bands; and an evenly banded dorsal pattern. Cyrtodactylus gunungsenyumensis sp. nov. is a scansorial, karst forest-adapted specialist endemic to the karst ecosystem surrounding Gunung Senyum and occurs on the vertical walls of the limestone towers as well as the branches, trunks, and leaves of the vegetation in the associated karst forest. Cyrtodactylus gunungsenyumensis sp. nov. is the seventh species of karst forest-adapted Cyrtodactylus and the sixteenth endemic species of karst ecosystem reptile discovered in Peninsular Malaysia in the last seven years from only 12 different karst forests. This is a clear indication that many species remain to be discovered in the approximately 558 isolated karst ecosystems in Peninsular Malaysia not yet surveyed. These data continue to underscore the importance of karst ecosystems as reservoirs of biodiversity and microendemism and that they constitute an important component of Peninsular Malaysia's natural heritage and should be protected from the quarrying interests of foreign industrial companies.

  11. Karst evolution in the Cordillera de la Sal (Atacama, Chili)

    NASA Astrophysics Data System (ADS)

    de Waele, J.; Forti, P.; Picotti, V.; Zini, L.; Cucchi, F.; Brook, G.

    2009-04-01

    Rock salt composed of halite is at least three orders of magnitude more soluble than limestone. Because of this very high solubility rock salt rarely crops out extensively at the surface and is readily dissolved leaving insoluble residue (mainly clays and marls). Rock salt can only survive at the surface where climate is extremely arid and normally displays a large set of typical solution morphologies similar to those developed on limestone. Solution of rock salt also leads to the formation of underground caves several km long. Close to the village of San Pedro de Atacama, North of the Salar de Atacama basin, there is an important NNE-SSW trending elongated anticlinal ridge composed of Oligo-Miocene evaporitic rocks known under the name Cordillera de la Sal. The thick salt beds of this ridge, even in this hyperarid climate (mean annual rainfall is below 20 mm/y and there may be no rain for several years), have been karstified by occasional rains and have a well developed surface karst geomorphology with extremely sharp rillenkarren often isolating salt pinnacles of up to 15 m in height. During the past 10 years interesting salt caves have been discovered in these halite beds and a detailed morphological study has been carried out both at the surface and in the most important caves with the aim of understanding the mechanisms responsible for their formation and evolution. Sixteen wood and bone fragments from the ceilings of caves and from diamictons in passages have been AMS radiocarbon dated, allowing us to determine when the cave systems formed and when the major sediment units were emplaced. In fact, cave formation appears to have been very rapid, with development of huge cave passages in salt (more than 10 m wide and 30 m high) in less than 2,000 years. Moreover, detailed surveys of cave morphology (e.g. meanders, erosion benches) and sediments (diamictons) suggest that the caves were formed by short-lived flash floods, probably produced by single extreme

  12. Geological and environmental implications of the evaporite karst in Spain

    NASA Astrophysics Data System (ADS)

    Gutiérrez, F.; Calaforra, J. M.; Cardona, F.; Ortí, F.; Durán, J. J.; Garay, P.

    2008-01-01

    In Spain, evaporite outcrops cover approximately 7% of the total area of the country. Most of the evaporitic formations are made up of Ca-sulfates (gypsum/anhydrite) or Ca-sulfates and halite. Certain Paleogene marine evaporites also contain K-Mg-chlorides, and some Tertiary continental formations bear substantial amounts of Na-sulfates in the subsurface (glauberite and thenardite). Mesozoic evaporitic formations commonly wedge out towards the ground surface, passing into condensed sequences and dissolution-collapse breccias. Some of these highly porous breccias constitute major regional aquifers. In several areas, interstratal karstification of the evaporites has given rise to gravitational deformations such as basin structures, monoclines, and collapse structures covering several square kilometers that record a cumulative subsidence in excess of 200 m (Teruel and Calatayud Grabens). A widespread consequence of evaporite dissolution processes in Spain is the hydrochemical degradation of surface waters. Some of the largest and most outstanding lake systems, from an environmental perspective, occur in karstic depressions developed in evaporitic formations (Fuente de Piedra, Gallocanta, Bujaraloz, and Bañolas lakes). Sinkhole activity is a major geohazard in several evaporite karst areas. The sinkhole risk has a particularly high impact in sectors where Tertiary evaporites are overlain by Quaternary alluvial aquifers (Calatayud, Zaragoza, and Madrid areas). Some of the detrimental effects of subsidence include severe damage to historical monuments (Calatayud), the demolition of a whole village (Puilatos), or the derailment of a freight train (Zaragoza area). The deepest gypsum caves are found in Triassic diapiric structures (El Sumidor Cave, 210 m deep), and the longest ones are developed in horizontally lying Neogene sequences (Sorbas caves, and Estremera maze cave). The Cardona diapir hosts salt caves up to 4,300 m long whose genesis is related to flooding of mine

  13. Sulfuric Acid Speleogenesis: Microbial Karst and Microbial Crust

    NASA Astrophysics Data System (ADS)

    Engel, A. S.; Bennett, P. C.; Stern, L. A.

    2001-12-01

    Sulfuric acid speleogenesis is a fundamental mechanism of karst formation, and is potentially responsible for the formation of some of the most extensive cave systems yet discovered. Speleogenesis occurs from the rapid dissolution of the host limestone by sulfuric acid produced from biotic and abiotic sulfide oxidation, and with the release of carbon dioxide, secondary gypsum crusts form. This crust develops predominately on the cave walls, often preserving original bedding indicators, until it finally collapses under its own weight to expose fresh limestone for dissolution. While this general speleogenetic process can be inferred from secondary residues in some caves, directly observing this process is difficult, and involves entry into an extreme environment with toxic atmospheres and low pH solutions. Kane Cave, Big Horn County, WY, offers the unique opportunity to study microbe-rock interactions directly. Kane Cave presently contains 3 springs that discharge hydrogen sulfide-rich waters, supporting thick subaqueous mats of diverse microbial communities in the stream passage. Condensation droplets and elemental sulfur form on subaerially exposed gypsum surfaces. Droplets have an average pH of 1.7, and are dominated by dissolved sulfate, Ca, Mg, Al, and Si, with minor Sr and Fe, and trace Mn and U. SEM and EDS examination of the crusts reveal the presence of C, O, and S, as well as authigenic, doubly-terminated quartz crystals. An average δ 13C value of -36 ‰ suggests that the crusts are biogenic and are composed of chemoautotrophic microorganisms. Enrichment cultures of biofilms and acid droplets rapidly produce sulfuric acid, demonstrating the dominance of sulfur-oxidizing bacteria. Colonization of gypsum surfaces by acidophilic microorganisms enhances acid dissolution of the limestone, and hence the growth of the cave itself. Limestone dissolution also results in mineralized crusts and biofilms that accumulate insoluble residues, which serve as sources of

  14. Processes Affecting Nitrogen Speciation in a Karst Aquifer

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Musgrove, M.; Wong, C. I.

    2011-12-01

    Like many karst aquifers, the Barton Springs segment of the Edwards aquifer, in central Texas, is in an area undergoing rapid growth in population, and there is concern as to how increased amounts of wastewater might affect groundwater quality. We measured concentrations and estimated loads of nitrogen (N) species in recharge to and discharge from the Barton Springs segment of the Edwards aquifer, central Texas, to evaluate processes affecting the transport and fate of N species in groundwater. Water samples were collected during 17 months (November 2008-March 2010) from five streams that contribute about 85% of recharge to the aquifer segment and from Barton Springs, the principal point of discharge from the segment. The sampling period spanned a range of climatic conditions from exceptional drought to above-normal rainfall. Samples were analyzed for N species (organic N + ammonia, ammonia, nitrate + nitrite, nitrite); loads of organic N and nitrate were estimated with LOADEST, a regression-based model that uses a time series of streamflow and measured constituent concentrations to estimate constituent loads. Concentrations of organic nitrogen and dissolved oxygen were higher and concentrations of nitrate were lower in surface water than in spring discharge, consistent with conversion of organic nitrogen to nitrate and associated consumption of dissolved oxygen in the aquifer. During the period of the study, the estimated load of organic N in recharge from streams (average daily load [adl] of 39 kg/d) was about 10 times that in Barton Springs discharge (adl of 9.4 kg/d), whereas the estimated load of nitrate in recharge from streams (adl of 123 kg/d) was slightly less than that in Barton Springs discharge (adl of 148 kg/d). The total average N load in recharge from streams and discharge from Barton Springs was not significantly different (adl of 162 and 157 kg/d, respectively), indicating that surface-water recharge can account for all of the N in Barton Springs

  15. Ultra-Wideband GPR Imaging of the Vaucluse Karst Aquifer

    NASA Astrophysics Data System (ADS)

    Dauvignac, J.; Fortino, N.; Sénéchal, G.; Cresp, A.; Yedlin, M.; Gaffet, S.; Rousset, D.; Pichot, C.

    2008-12-01

    In this paper, we present the validation of an Ultra Wide band measurement system which is the first experimental step of the French MAXWELL Research Project devoted to the survey of the karst aquifer located in the Vaucluse in Provence. This radar system employs Exponentially Tapered Slot Antennas (ETSA), with a usable bandwidth from 100 MHz to 2.5 GHz. The antenna is driven by a .01- 26.5 GHz Agilent vector network analyzer (VNA), with a noise floor of -120dB under test conditions and a noise floor of -100 dB in a field setting. A synthetic pulse is applied to the antenna by using a classical step frequency sweeping. The recorded amplitudes and phases of the reflection coefficient (S11 parameter) are filtered and inverse Fourier transformed to obtain the time-domain data. In principal, due to the flat radiation characteristic of the frequency generator, appropriate synthetic pulses can be generated for analysis. The advantages of this approach are mainly, 1) a large depth resolution due to increased bandwidth, 2) a wider dynamic range for detection of weak late underground echoes, 3) a low signal distortion due to absence of pulse deconvolution post-processing. The foregoing system was deployed inside a tunnel in the Low-Noise Underground Laboratory (LSBB) located in Rustrel (France) which allows the use of low power radiation. Minimization of noise interference was accomplished by : 1) using low noise and low-loss cables, 2) using a PVC structure covered with absorbers to shield the ETSA from unwanted tunnel wall reflections and from radiation from the vector network analyzer, 3) an effective calibration of long cables to the antenna connector with careful cable unwinding to reduce phase errors, 4) a power level fixed at 8 dBm in the frequency band of interest to avoid distortion in the mixer of the VNA. Monostatic or multistatic data, were collected by moving manually the antennas along the PVC frame, in 5 cm increments over a length of 6 m. Both parallel and

  16. Oil and Gas Drilling and Operations in Cave and Karst area: Background and development of a BLM approach

    SciTech Connect

    Goodbar, J.R. )

    1994-03-01

    Karst lands pose a unique set of problems for the oil and gas industry, as well as for the cave and karst environments. Since 1987, the Bureau of Land Management (BLM) has been working with the oil and gas industry to develop acceptable practices for drilling and operation in karst lands. The mutual goals of industry and of the BLM is to minimize the potential of encountering those problems and reduce the extent of the problems, if they are encountered. BLM's approach is described in their [open quotes]Draft Guide for Oil and Gas Drilling and Operations in Cave and Karst Areas.[close quotes] This paper discusses the background and development of this guide with an emphasis on the conflict resolution approach of the BLM.

  17. Structural control in sinkhole development and speleogenesis: a case study from the High Murge karst landscape (Apulia, Italy)

    NASA Astrophysics Data System (ADS)

    Pepe, M.; Parise, M.

    2012-04-01

    The Murge plateau is the main karst sector of Apulia, an almost entirely carbonate region of SE Italy. It can be, in turn, subdivided into two sectors: High Murge, the inland plateau, where remnants of an ancient tropical karst are still recognizable; and Low Murge, closer to the Adriatic Sea, with smoother karst morphologies and landforms, but, at the same time, hosting some of the longest underground karst system in the region (Parise, 1998, 2006). Even though showing low energy relief, the landscape of High Murge is very articulated when examined at greater detail, with several interesting karst features. Among these, sinkholes are definitely the most significant, showing a variety of typologies and, at the same time, a high frequency, both as individual features and as coalescent landforms, giving origin to more complex depressions (Parise, 2011). Previous studies carried out in the High Murge through morphometric analysis of the main sinkholes identified on the 1:25,000 scale topographic maps from the Italian Army Geographical Institute indicated their likely genesis in a low relief cockpit karst (Sauro, 1991). Over such landscape, developed in Upper Tertiary, a hydrographic pattern was superimposed, that partly opened some of the depressions, also dismantling sectors of the karst relief and producing talus deposits (Caldara & Ciaranfi, 1988). In the present work we take into consideration the southern countryside of Ruvo di Puglia. Choice of the area, which extends over 15 km2, was dictated by presence of a high number of sinkholes, and of several important caves with prevailing vertical development, including the deepest pit ever explored in Apulia (Grave della Ferratella, depth - 320 m). The cave is nowadays not accessible, due to clogging caused by land use changes during the 80's. Based upon extensive field surveys and interpretation of multi-year aerial photographs (time range 1955-2003), integrated by surveying in selected caves, the main hydro

  18. Reducing the ambiguity of karst aquifer models by pattern matching of flow and transport on catchment scale

    NASA Astrophysics Data System (ADS)

    Oehlmann, S.; Geyer, T.; Licha, T.; Sauter, M.

    2015-02-01

    Assessing the hydraulic parameters of karst aquifers is a challenge due to their high degree of heterogeneity. The unknown parameter field generally leads to a high ambiguity for flow and transport calibration in numerical models of karst aquifers. In this study, a distributed numerical model was built for the simulation of groundwater flow and solute transport in a highly heterogeneous karst aquifer in south-western Germany. Therefore, an interface for the simulation of solute transport in one-dimensional pipes was implemented into the software COMSOL Multiphysics® and coupled to the three-dimensional solute transport interface for continuum domains. For reducing model ambiguity, the simulation was matched for steady-state conditions to the hydraulic head distribution in the model area, the spring discharge of several springs and the transport velocities of two tracer tests. Furthermore, other measured parameters such as the hydraulic conductivity of the fissured matrix and the maximal karst conduit volume were available for model calibration. Parameter studies were performed for several karst conduit geometries to analyse the influence of the respective geometric and hydraulic parameters and develop a calibration approach in a large-scale heterogeneous karst system. Results show that it is possible not only to derive a consistent flow and transport model for a 150 km2 karst area but also to combine the use of groundwater flow and transport parameters thereby greatly reducing model ambiguity. The approach provides basic information about the conduit network not accessible for direct geometric measurements. The conduit network volume for the main karst spring in the study area could be narrowed down to approximately 100 000 m3.

  19. Reducing the ambiguity of karst aquifer models by pattern matching of flow and transport on catchment scale

    NASA Astrophysics Data System (ADS)

    Oehlmann, S.; Geyer, T.; Licha, T.; Sauter, M.

    2014-08-01

    Assessing the hydraulic parameters of karst aquifers is a challenge due to their high degree of heterogeneity. The unknown parameter field generally leads to a high ambiguity for flow and transport calibration in numerical models of karst aquifers. In this study, a distributive numerical model was built for the simulation of groundwater flow and solute transport in a highly heterogeneous karst aquifer in south western Germany. Therefore, an interface for the simulation of solute transport in one-dimensional pipes was implemented into the software Comsol Multiphysics® and coupled to the three-dimensional solute transport interface for continuum domains. For reducing model ambiguity, the simulation was matched for steady-state conditions to the hydraulic head distribution in the model area, the spring discharge of several springs and the transport velocities of two tracer tests. Furthermore, other measured parameters such as the hydraulic conductivity of the fissured matrix and the maximal karst conduit volume were available for model calibration. Parameter studies were performed for several karst conduit geometries to analyse the influence of the respective geometric and hydraulic parameters and develop a calibration approach in a large-scale heterogeneous karst system. Results show that it is not only possible to derive a consistent flow and transport model for a 150 km2 karst area, but that the combined use of groundwater flow and transport parameters greatly reduces model ambiguity. The approach provides basic information about the conduit network not accessible for direct geometric measurements. The conduit network volume for the main karst spring in the study area could be narrowed down to approximately 100 000 m3.

  20. Picos de Europa National and Regional parks (Northern Spain): the karst underground landscape

    NASA Astrophysics Data System (ADS)

    Ballesteros, Daniel; Jiménez-Sánchez, Montserrat; Rodríguez-Rodríguez, Laura; José Domínguez-Cuesta, María; Meléndez-Asensio, Mónica; García-Sansegundo, Joaquín

    2015-04-01

    Karst caves represent an environmental with a high value from the Geoheritage and Geodiversity points of view given by hidden underground landscape practically reserved to the speleologists. Nevertheless, cave surveys, 3d models of caves and DEMs, and pictures can be used to approach the endokarst geoheritage characterization. The Picos de Europa National and Regional parks include the 14% of World's Deepest Caves (>1 km depth); moreover these parks shows a high environmental value related with seven protection figures: Biosphere Reserve, Special Protection Area, the Site of Community Importance, and four Natural Monument. The aim of this work is to present the Geoheritage values of the underground landscape of the Picos de Europa National and Regional parks. These parks involve several alpine karst massifs up to 700 km2 and 2,600 m asl, as the Picos de Europa mountains (declared Global Geosite by its geomorphological interest), the Mampodre Massif, and the Peñas Pintas and Yordas peaks (sited in Riaño dam area). The alpine karst involves a large underground landscape formed by more than 3,700 epigenic caves with 403 km of conduits. The 95 % of the cave conduits are located in the Picos de Europa mountains and correspond to caves up to 18.9 km length and 1.6 km depth; the 5 % of cave conduits are sited in other small karst areas and include caves up to 1.5 km length and 200 m depth. The karst caves present high natural, scientific and cultural values. The natural value corresponds to the singularity and the spectacular vertical development of the caves and a very high Geodiversity of cave features. The karst shows a high concentration of deep caves (81 caves deeper than 500 m) that is twice higher than the concentration of other karst areas, as Arabika Massif (Western Caucasus). The natural value is mainly related to the presence of geomorphological and hydrogeological features, highlighting high vadose canyons and shafts, old phreatic and epiphreatic conduits

  1. Effects of karst and geologic structure on the circulation of water and permeability in carbonate aquifers

    USGS Publications Warehouse

    Stringfield, V.T.; Rapp, J.R.; Anders, R.B.

    1979-01-01

    The results of the natural processes caused by solution and leaching of limestone, dolomite, gypsum, salt and other soluble rocks, is known as karst. Development of karst is commonly known as karstification, which may have a pronounced effect on the topography, hydrology and environment, especially where such karst features as sinkholes and vertical solution shafts extend below the land surface and intersect lateral solution passages, cavities, caverns and other karst features in carbonate rocks. Karst features may be divided into two groups: (1) surficial features that do not extend far below the surface; and (2) karst features such as sinkholes that extend below the surface and affect the circulation of water below. The permeability of the most productive carbonate aquifers is due chiefly to enlargement of fractures and other openings by circulation of water. Important controlling factors responsible for the development of karst and permeability in carbonate aquifers include: (1) climate, topography, and presence of soluble rocks; (2) geologic structure; (3) nature of underground circulation; and (4) base level. Another important factor is the condition of the surface of the carbonate rocks at the time they are exposed to meteoric water. A carbonate rock surface, with soil or relatively permeable, less soluble cover, is more favorable for initiation of karstification and solution than bare rocks. Water percolates downward through the cover to the underlying carbonate rocks instead of running off on the surface. Also, the water becomes more corrosive as it percolates through the permeable cover to the underlying carbonate rocks. Where there is no cover or the cover has been removed, the carbonate rocks become case hardened and resistant to erosion. However, in regions underlain not only by carbonate rocks but also by beds of anhydrite, gypsum and salt, such as the Hueco Plateau in southeastern New Mexico, subsurface solution may occur where water without natural

  2. Effectiveness of airborne multispectral thermal data for karst groundwater resources recognition in coastal areas

    NASA Astrophysics Data System (ADS)

    Pignatti, Stefano; Fusilli, Lorenzo; Palombo, Angelo; Santini, Federico; Pascucci, Simone

    2013-04-01

    Currently the detection, use and management of groundwater in karst regions can be considered one of the most significant procedures for solving water scarcity problems during periods of low rainfall this because groundwater resources from karst aquifers play a key role in the water supply in karst areas worldwide [1]. In many countries of the Mediterranean area, where karst is widespread, groundwater resources are still underexploited, while surface waters are generally preferred [2]. Furthermore, carbonate aquifers constitute a crucial thermal water resource outside of volcanic areas, even if there is no detailed and reliable global assessment of thermal water resources. The composite hydrogeological characteristics of karst, particularly directions and zones of groundwater distribution, are not up till now adequately explained [3]. In view of the abovementioned reasons the present study aims at analyzing the detection capability of high spatial resolution thermal remote sensing of karst water resources in coastal areas in order to get useful information on the karst springs flow and on different characteristics of these environments. To this purpose MIVIS [4, 5] and TASI-600 [6] airborne multispectral thermal imagery (see sensors' characteristics in Table 1) acquired on two coastal areas of the Mediterranean area interested by karst activity, one located in Montenegro and one in Italy, were used. One study area is located in the Kotor Bay, a winding bay on the Adriatic Sea surrounded by high mountains in south-western Montenegro and characterized by many subaerial and submarine coastal springs related to deep karstic channels. The other study area is located in Santa Cesarea (Italy), encompassing coastal cold springs, the main local source of high quality water, and also a noticeable thermal groundwater outflow. The proposed study shows the preliminary results of the two airborne deployments on these areas. The preprocessing of the multispectral thermal imagery

  3. A Compilation of Provisional Karst Geospatial Data for the Interior Low Plateaus Physiographic Region, Central United States

    USGS Publications Warehouse

    Taylor, Charles J.; Nelson, Hugh L.

    2008-01-01

    Geospatial data needed to visualize and evaluate the hydrogeologic framework and distribution of karst features in the Interior Low Plateaus physiographic region of the central United States were compiled during 2004-2007 as part of the Ground-Water Resources Program Karst Hydrology Initiative (KHI) project. Because of the potential usefulness to environmental and water-resources regulators, private consultants, academic researchers, and others, the geospatial data files created during the KHI project are being made available to the public as a provisional regional karst dataset. To enhance accessibility and visualization, the geospatial data files have been compiled as ESRI ArcReader data folders and user interactive Published Map Files (.pmf files), all of which are catalogued by the boundaries of surface watersheds using U.S. Geological Survey (USGS) eight-digit hydrologic unit codes (HUC-8s). Specific karst features included in the dataset include mapped sinkhole locations, sinking (or disappearing) streams, internally drained catchments, karst springs inventoried in the USGS National Water Information System (NWIS) database, relic stream valleys, and karst flow paths obtained from results of previously reported water-tracer tests.

  4. GIS-based assessment of groundwater level on extensive karst areas

    NASA Astrophysics Data System (ADS)

    Kopecskó, Zsanett; Józsa, Edina

    2016-04-01

    Karst topographies represent unique geographical regions containing caves and extensive underground water systems developed especially on soluble rocks such as limestone, marble and gypsum. The significance of these areas is evident considering that 12% of the ice-free continental area consists of landscapes developed on carbonate rocks and 20-25% of the global population depends mostly on groundwater obtained from these systems. Karst water reservoirs already give the 25% of the freshwater resources globally. Comprehensive studies considering these regions are the key to explore chances of the exploitation and to analyze the consequences of contamination, anthropogenic effects and natural processes within these specific hydro-geological characteristics. For the proposed work we chose several of the largest karst regions over the ice-free part of continents, representing diverse climatic and topographic characteristics. An important aspect of the study is that there are no available in situ hydrologic measurements over the entire research area that would provide discrete sampling of soil, ground and surface water. As replacement for the detailed surveys, multi remote sensing data (Gravity Recovery and Climate Experiment (GRACE) satellite derivatives products, Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products and Tropical Rainfall Measuring Mission (TRMM) monthly rainfalls satellite datasets) are used along with model reanalysis data (Global Precipitation Climate Center data (GPCC) and Global Land Data Assimilation System (GLDAS)) to study the variation on extensive karst areas in response to the changing climate and anthropogenic effects. The analyses are carried out within open source software environment to enable sharing of the proposed algorithm. The GRASS GIS geoinformatic software and the R statistical program proved to be adequate choice to collect and analyze the above mentioned datasets by taking advantage of their interoperability

  5. Carbon Storage in an Extensive Karst-distributed Region of Southwestern China based on Multiple Methods

    NASA Astrophysics Data System (ADS)

    Guo, C.; Wu, Y.; Yang, H.; Ni, J.

    2015-12-01

    Accurate estimation of carbon storage is crucial to better understand the processes of global and regional carbon cycles and to more precisely project ecological and economic scenarios for the future. Southwestern China has broadly and continuously distribution of karst landscapes with harsh and fragile habitats which might lead to rocky desertification, an ecological disaster which has significantly hindered vegetation succession and economic development in karst regions of southwestern China. In this study we evaluated the carbon storage in eight political divisions of southwestern China based on four methods: forest inventory, carbon density based on field investigations, CASA model driven by remote sensing data, and BIOME4/LPJ global vegetation models driven by climate data. The results show that: (1) The total vegetation carbon storage (including agricultural ecosystem) is 6763.97 Tg C based on the carbon density, and the soil organic carbon (SOC) storage (above 20cm depth) is 12475.72 Tg C. Sichuan Province (including Chongqing) possess the highest carbon storage in both vegetation and soil (1736.47 Tg C and 4056.56 Tg C, respectively) among the eight political divisions because of the higher carbon density and larger distribution area. The vegetation carbon storage in Hunan Province is the smallest (565.30 Tg C), and the smallest SOC storage (1127.40 Tg C) is in Guangdong Province; (2) Based on forest inventory data, the total aboveground carbon storage in the woody vegetation is 2103.29 Tg C. The carbon storage in Yunnan Province (819.01 Tg C) is significantly higher than other areas while tropical rainforests and seasonal forests in Yunnan contribute the maximum of the woody vegetation carbon storage (account for 62.40% of the total). (3) The net primary production (NPP) simulated by the CASA model is 68.57 Tg C/yr, while the forest NPP in the non-karst region (account for 72.50% of the total) is higher than that in the karst region. (4) BIOME4 and LPJ

  6. The water circulation in the fractured rock: the role of stylolites in the development of karst

    NASA Astrophysics Data System (ADS)

    Magni, Silvana

    2015-04-01

    Karst development is strongly influenced by the tectonic deformation of the area where they occur.This is because, the structure of the rock mass in which it occurs (eg. lithology, primary porosisty, environmental conditions, etc) affects the water circulation, thereby affecting permeability and porosity.Traditionally, in the field of karstology, it is maintained that water circulation is essentially related to extensional structures which, it is assumed, are more favorable to water circulation. In fact, the permeability of the fault zone is sufficiently high only in the early stages of the movement , because after a short period the deposition of minerals (e.g., calcite) coming from these same fluids reduces its porosity/permeability.Fault zones and fractures play an important role in fluid circulation, acting as permeability barriers or conductors, depending on the specific conditions (lithological and structural in particular), and on the distribution of other structures associated with them. Therefore, structural analysis can provide both qualitative and quantitative assessments of the relationship between structure and fluid circulation and allow us to determine whether a fault zone acts as a barrier or as a hydraulic conductor (Caine 1996).The stylolites (Rawling 2001), structure associated with the faults play an important role in the fluid circulation and in particular in the development of the karst.In this study, conducted in the karst area of Fasano(south Italy) it was verified that the karst tends to develop along tectonic stylolites formed by compression. The analysis performed(structural, XRD, on permeability) are allowing us to take the first considerations on the importance of stylolites in the development of karst. The relationship between stylolites, karst and fluid circulation is nowadays very important and of great interest in the study of carbonate reservoirs. Indeed,the aquifers represent about 40% of sources of drinking water and their

  7. ADAPTATIONS OF INDIGENOUS BACTERIA TO FUEL CONTAMINATION IN KARST AQUIFERS IN SOUTH-CENTRAL KENTUCKY

    USGS Publications Warehouse

    Byl, Thomas D.; Metge, David W.; Daniel T. Agymang,; Bradley, Michael W.; Hileman, Gregg; Harvey, Ronald W.

    2014-01-01

    The karst aquifer systems in southern Kentucky can be dynamic and quick to change. Microorganisms that live in these unpredictable aquifers are constantly faced with environmental changes. Their survival depends upon adaptations to changes in water chemistry, taking advantage of positive stimuli and avoiding negative environmental conditions. The U.S. Geological Survey conducted a study in 2001 to determine the capability of bacteria to adapt in two distinct regions of water quality in a karst aquifer, an area of clean, oxygenated groundwater and an area where the groundwater was oxygen depleted and contaminated by jet fuel. Water samples containing bacteria were collected from one clean well and two jet fuel contaminated wells in a conduit-dominated karst aquifer. Bacterial concentrations, enumerated through direct count, ranged from 500,000 to 2.7 million bacteria per mL in the clean portion of the aquifer, and 200,000 to 3.2 million bacteria per mL in the contaminated portion of the aquifer over a twelve month period. Bacteria from the clean well ranged in size from 0.2 to 2.5 mm, whereas bacteria from one fuel-contaminated well were generally larger, ranging in size from 0.2 to 3.9 mm. Also, bacteria collected from the clean well had a higher density and, consequently, were more inclined to sink than bacteria collected from contaminated wells. Bacteria collected from the clean portion of the karst aquifer were predominantly (,95%) Gram-negative and more likely to have flagella present than bacteria collected from the contaminated wells, which included a substantial fraction (,30%) of Gram-positive varieties. The ability of the bacteria from the clean portion of the karst aquifer to biodegrade benzene and toluene was studied under aerobic and anaerobic conditions in laboratory microcosms. The rate of fuel biodegradation in laboratory studies was approximately 50 times faster under aerobic conditions as compared to anaerobic, sulfur-reducing conditions. The

  8. An Examination of the Application of Professional Reliance To Management of Karst Resources In British Columbia (Canada)

    NASA Astrophysics Data System (ADS)

    Ramsey, Carolyn L.; Griffiths, Paul A.

    2010-05-01

    British Columbia (BC), Canada's most ecologically diverse province, is home to some of the nation's finest karst resources. Many of these are in forested settings, and are often associated with special/unique natural attributes ranging from geomorphology to hydrology, biology and ecology. Karst management in BC forests was shaped initially by concerns for caves and their recreation management, but as of 1997 there was a significant shift to an ecosystem approach to management of karst and cave resources. This new management approach was supported in due course by standards and guidelines for karst assessment and management. The approach also recognized the inherently multidisciplinary nature of this type of work and the frequent need to engage professionals with specialized knowledge of karst, and its natural and cultural resource values. In 2004, the BC Government introduced the Forest and Range Practices Act, a new results-based regulatory framework for forest practices. Government orders made pursuant to regulations under the Act identify categories of karst terrain and associated resource features that must be protected from the potentially damaging effects of roadbuilding and road maintenance, timber harvesting, and silviculture activities. In support of a general shift toward more results-based regulation and "freedom to manage" forest resources, it was argued that the forestry sector and its professionals are qualified, and competent enough, to formulate strategies for protecting and managing forest resources (including karst) without as much government oversight. As a result, forest tenure holders and their professionals are now responsible for assessing protected categories of karst resource features and developing and applying appropriate forest practices for them. Where knowledge beyond the area of forest professionals' expertise is required, the knowledge gaps are to be addressed by hiring suitably qualified professional consultants for advice and

  9. Assessment of the potential for karst in the Rustler Formation at the WIPP site.

    SciTech Connect

    Lorenz, John Clay

    2006-01-01

    This report is an independent assessment of the potential for karst dissolution in evaporitic strata of the Rustler Formation at the Waste Isolation Pilot Plant (WIPP) site. Review of the available data suggests that the Rustler strata thicken and thin across the area in depositional patterns related to lateral variations in sedimentary accommodation space and normal facies changes. Most of the evidence that has been offered for the presence of karst in the subsurface has been used out of context, and the different pieces are not mutually supporting. Outside of Nash Draw, definitive evidence for the development of karst in the Rustler Formation near the WIPP site is limited to the horizon of the Magenta Member in drillhole WIPP-33. Most of the other evidence cited by the proponents of karst is more easily interpreted as primary sedimentary structures and the localized dissolution of evaporitic strata adjacent to the Magenta and Culebra water-bearing units. Some of the cited evidence is invalid, an inherited baggage from studies made prior to the widespread knowledge of modern evaporite depositional environments and prior to the existence of definitive exposures of the Rustler Formation in the WIPP shafts. Some of the evidence is spurious, has been taken out of context, or is misquoted. Lateral lithologic variations from halite to mudstone within the Rustler Formation under the WIPP site have been taken as evidence for the dissolution of halite such as that seen in Nash Draw, but are more rationally explained as sedimentary facies changes. Extrapolation of the known karst features in Nash Draw eastward to the WIPP site, where conditions are and have been significantly different for half a million years, is unwarranted. The volumes of insoluble material that would remain after dissolution of halite would be significantly less than the observed bed thicknesses, thus dissolution is an unlikely explanation for the lateral variations from halite to mudstone and siltstone

  10. Surface-water and karst groundwater interactions and streamflow-response simulations of the karst-influenced upper Lost River watershed, Orange County, Indiana

    USGS Publications Warehouse

    Bayless, E. Randall; Cinotto, Peter J.; Ulery, Randy L.; Taylor, Charles J.; McCombs, Gregory K.; Kim, Moon H.; Nelson, Hugh L.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers (USACE) and the Indiana Office of Community and Rural Affairs (OCRA), conducted a study of the upper Lost River watershed in Orange County, Indiana, from 2012 to 2013. Streamflow and groundwater data were collected at 10 data-collection sites from at least October 2012 until April 2013, and a preliminary Water Availability Tool for Environmental Resources (WATER)-TOPMODEL based hydrologic model was created to increase understanding of the complex, karstic hydraulic and hydrologic system present in the upper Lost River watershed, Orange County, Ind. Statistical assessment of the optimized hydrologic-model results were promising and returned correlation coefficients for simulated and measured stream discharge of 0.58 and 0.60 and Nash-Sutcliffe efficiency values of 0.56 and 0.39 for USGS streamflow-gaging stations 03373530 (Lost River near Leipsic, Ind.), and 03373560 (Lost River near Prospect, Ind.), respectively. Additional information to refine drainage divides is needed before applying the model to the entire karst region of south-central Indiana. Surface-water and groundwater data were used to tentatively quantify the complex hydrologic processes taking place within the watershed and provide increased understanding for future modeling and management applications. The data indicate that during wet-weather periods and after certain intense storms, the hydraulic capacity of swallow holes and subsurface conduits is overwhelmed with excess water that flows onto the surface in dry-bed relic stream channels and karst paleovalleys. Analysis of discharge data collected at USGS streamflow-gaging station 03373550 (Orangeville Rise, at Orangeville, Ind.), and other ancillary data-collection sites in the watershed, indicate that a bounding condition is likely present, and drainage from the underlying karst conduit system is potentially limited to near 200 cubic feet per second. This

  11. Carbon dioxide, ground air and carbon cycling in Gibraltar karst

    NASA Astrophysics Data System (ADS)

    Mattey, D. P.; Atkinson, T. C.; Barker, J. A.; Fisher, R.; Latin, J.-P.; Durrell, R.; Ainsworth, M.

    2016-07-01

    We put forward a general conceptual model of CO2 behaviour in the vadose zone of karst aquifers, based on physical principles of air flow through porous media and caves, combined with a geochemical interpretation of cave monitoring data. This 'Gibraltar model' links fluxes of water, air and carbon through the soil with the porosity of the vadose zone, the circulation of ground air and the ventilation of caves. Gibraltar hosts many natural caves whose locations span the full length and vertical range of the Rock. We report results of an 8-year monitoring study of carbon in soil organic matter and bedrock carbonate, dissolved inorganic carbon in vadose waters, and gaseous CO2 in soil, cave and ground air. Results show that the regime of cave air CO2 results from the interaction of cave ventilation with a reservoir of CO2-enriched ground air held within the smaller voids of the bedrock. The pCO2 of ground air, and of vadose waters that have been in close contact with it, are determined by multiple factors that include recharge patterns, vegetation productivity and root respiration, and conversion of organic matter to CO2 within the soil, the epikarst and the whole vadose zone. Mathematical modelling and field observations show that ground air is subject to a density-driven circulation that reverses seasonally, as the difference between surface and underground temperatures reverses in sign. The Gibraltar model suggests that cave air pCO2 is not directly related to CO2 generated in the soil or the epikarstic zone, as is often assumed. Ground air CO2 formed by the decay of organic matter (OM) washed down into the deeper unsaturated zone is an important additional source of pCO2. In Gibraltar the addition of OM-derived CO2 is the dominant control on the pCO2 of ground air and the Ca-hardness of waters within the deep vadose zone. The seasonal regime of CO2 in cave air depends on the position of a cave in relation to the density-driven ground air circulation pattern which

  12. Hydrologically-driven variations in the karst-related carbon sink fluxes: Insights from high-resolution monitoring of three karst catchments in Southwest China

    NASA Astrophysics Data System (ADS)

    Zeng, Cheng; Liu, Zaihua; Zhao, Min; Yang, Rui

    2016-02-01

    Rainfall (P), discharge (Q), water temperature, pH, and specific electrical conductivity (EC) of the three karst catchments, Banzhai, Huanghou and Houzhai, with different land uses and carbonate lithologies but similar subtropical monsoonal climate, in Guizhou Province, Southwest China, were monitored with CTDP 300 high-resolution multi-parameter data loggers during the period of May 2007-October 2013. In addition, HCO3- and calcium concentrations were titrated in the field and the other major ions determined in the laboratory once every one or two months. Simple linear regression models were used to link the continuous chemical data to in situ measured data to estimate the concentration of HCO3-, the CO2 partial pressures and the calcite saturation indices on the high-resolution logger data. Continuous karst-related carbon sink fluxes (CSFs) were also estimated with the continuous Q and HCO3- concentrations in each catchment area. The primary goal of this study is to understand how discharge and HCO3- concentration determine the CSFs at the storm scale, seasonal scale and annual scale, and to estimate the CSFs for the three studied catchments. Results show that the variation in runoff (river discharge) played a more important role in controlling the CSFs than the variation in HCO3- for all the karst catchments, because of the chemostatic behavior of HCO3- in the catchments. Soil coverage, vegetation and bedrock lithology determined the CSFs by controlling the proportion of precipitation that recharges groundwater (and thus Q), and controlling the soil CO2 productivity (and thus HCO3-). The average CSFs in the Banzhai, Huanghou and Houzhai karst catchments were 29 ± 3, 33 ± 5 and 39 ± 8 t-CO2 km-2 a-1, respectively, which are 15 times higher than those CSFs by silicate weathering in the silicate-rock catchments with similar hydrology, showing the dominant role of carbonate weathering in the rock-weathering-related carbon sink. The interannual change in CSFs was

  13. Community diversity, structure and carbon footprint of nematode food web following reforestation on degraded Karst soil.

    PubMed

    Hu, Ning; Li, Hui; Tang, Zheng; Li, Zhongfang; Tian, Jing; Lou, Yilai; Li, Jianwei; Li, Guichun; Hu, Xiaomin

    2016-01-01

    We examined community diversity, structure and carbon footprint of nematode food web along a chronosequence of T. Sinensis reforestation on degraded Karst. In general, after the reforestation: a serious of diversity parameters and community indices (Shannon-Weinier index (H'), structure index (SI), etc.) were elevated; biomass ratio of fungivores to bacterivores (FFC/BFC), and fungi to bacteria (F/B) were increased, and nematode channel ratio (NCR) were decreased; carbon footprints of all nematode trophic groups, and biomass of bacteria and fungi were increased. Our results indicate that the Karst aboveground vegetation restoration was accompanied with belowground nematode food web development: increasing community complexity, function and fungal dominance in decomposition pathway, and the driving forces included the bottom-up effect (resource control), connectedness of functional groups, as well as soil environments. PMID:27311984

  14. Freshwater biodissolution rates of limestone in the temperate climate of the Dinaric karst in Slovenia

    NASA Astrophysics Data System (ADS)

    Mulec, J.; Prelovšek, M.

    2015-01-01

    Dissolution rates in two freshwater karst systems were determined by using tablets of dense micrite-biopelmicrite Cretaceous limestone. Submerged limestone tablets in riverbeds were subjected to a natural gradient from complete darkness to direct sunlight. Higher light rates significantly (p < 0.05) increased the epilithic biomass of phototrophs and the overall dissolution rates, which were highest at the Unica spring (- 49.2 μm a- 1), but the exact portion of light-dependent dissolution remains elusive. In the karst river Unica, with its big fluctuations in environmental parameters (e.g., discharge), light rates can be used in estimating the dissolution rates enhanced by phototrophs. Natural biofilms in aquatic systems have important implications for landform evolution, and the impact on limestone dissolution rates is comparable with rates of debris falling from steep slopes.

  15. Distribution of polycyclic aromatic hydrocarbons in Datuo karst Tiankeng of South China.

    PubMed

    Theodore, Oramah I; Qi, Shihua; Kong, Xiangsheng; Liu, Huafeng; Li, Jun; Li, Jie; Wang, Xiangqing; Wang, Yinhui

    2008-10-01

    Levels of polycyclic aromatic hydrocarbons (PAHs) were measured in surface soils of Datuo karst Tiankeng (large sinkholes) in South China with the use of a gas chromatography-mass spectroscopy (GC-MS) system. This paper provides data on the levels and distribution of PAHs from the top to the bottom of the Datuo karst Tiankeng. The results showed that the sum of the 16 EPA priority PAHs from the sampled locations from top to bottom had a relative increment in PAHs concentration. summation operatorPAHs ranged from 16.93 ng/g to 68.07 ng/g with a mean concentration of 42.15 ng/g. The correlated results showed the bottom of the large sinkhole, which accounts for the higher concentrations, probably acts like a trap for the PAHs. Thus, the low evaporation rate at the bottom may play a key role in controlling the high concentration of PAHs at the bottom.

  16. Study on the contamination of fracture-karst water in Boshan District, China

    SciTech Connect

    Zhu, X.Y.; Xu, S.H.; Zhu, J.J.; Zhou, N.Q.; Wu, C.Y.

    1997-05-01

    Boshan is an industrial city in the center of Shandong Province where ground water is the only source for the urban water supply. The major water resource is fracture-karst water in the middle Ordovician carbonate rocks. Based on the hydrogeologic investigation and mapping in this area, the authors studied the geologic and hydrogeologic settings, the major pollution sources and the pathways of contamination, the principal contaminants, and their spatial distribution in ground water. The ground-water quality has also been estimated by the fuzzy mathematic method. The geostatistical method, such as the kriging method, was taken to simulate spatial distribution of the contaminants. The grey system method was adopted to forecast future contamination. An attempt at the remediation of Cr{sup 6+} contamination in fracture-karst water was also discussed. Finally, some proposals for the protection of the ground-water environment in Boshan District are offered.

  17. U.S. Geological Survey Karst Interest Group Proceedings, Fayetteville, Arkansas, April 26-29, 2011

    USGS Publications Warehouse

    Kuniansky, Eve L.

    2011-01-01

    This fifth workshop is a joint workshop of the USGS Karst Interest Group and University of Arkansas HydroDays workshop, sponsored by the USGS, the Department of Geosciences at the University of Arkansas in Fayetteville. Additional sponsors are: the National Cave and Karst Research Institute, the Edwards Aquifer Authority, San Antonio, Texas, and Beaver Water District, northwest Arkansas. The majority of funding for the proceedings preparation and workshop was provided by the USGS Groundwater Resources Program, National Cooperative Mapping Program, and the Regional Executives of the Northeast, Southeast, Midwest, South Central and Rocky Mountain Areas. The University of Arkansas provided the rooms and facilities for the technical and poster presentations of the workshop, vans for the field trips, and sponsored the HydroDays banquet at the Savoy Experimental Watershed on Wednesday after the technical sessions.

  18. USGS geologic Mapping and karst research in the Ozark National Scenic Riverways, Missouri, USA

    USGS Publications Warehouse

    Weary, David J.; Grant, Victoria M

    2014-01-01

    The Ozark National Scenic Riverways (ONSR) was created in 1964 to protect 134 miles of the Current River and its major tributary, the Jacks Fork, that are located in south-central Missouri (fig. 1). The park includes numerous large karst springs including Big Spring, by flow volume this is the largest spring in the National Park system. The National Park Service (NPS) administers a narrow, nearly continuous corridor of land adjacent to the two rivers. Base flow for the rivers is chiefly supplied by groundwater that has traveled through the karst landscape from as far as 38 miles away from the spring (Imes and Frederick, 2002). The watershed is vulnerable to pollution, but the area remains largely rural with few industries. The springs and rivers provide habitat for numerous aquatic species as well as recreational resources for floaters, fishermen, and campers. The ONSR is a major cave park with hundreds of known caves and diverse in-cave resources.

  19. Community diversity, structure and carbon footprint of nematode food web following reforestation on degraded Karst soil

    NASA Astrophysics Data System (ADS)

    Hu, Ning; Li, Hui; Tang, Zheng; Li, Zhongfang; Tian, Jing; Lou, Yilai; Li, Jianwei; Li, Guichun; Hu, Xiaomin

    2016-06-01

    We examined community diversity, structure and carbon footprint of nematode food web along a chronosequence of T. Sinensis reforestation on degraded Karst. In general, after the reforestation: a serious of diversity parameters and community indices (Shannon-Weinier index (H‧), structure index (SI), etc.) were elevated; biomass ratio of fungivores to bacterivores (FFC/BFC), and fungi to bacteria (F/B) were increased, and nematode channel ratio (NCR) were decreased; carbon footprints of all nematode trophic groups, and biomass of bacteria and fungi were increased. Our results indicate that the Karst aboveground vegetation restoration was accompanied with belowground nematode food web development: increasing community complexity, function and fungal dominance in decomposition pathway, and the driving forces included the bottom-up effect (resource control), connectedness of functional groups, as well as soil environments.

  20. Community diversity, structure and carbon footprint of nematode food web following reforestation on degraded Karst soil.

    PubMed

    Hu, Ning; Li, Hui; Tang, Zheng; Li, Zhongfang; Tian, Jing; Lou, Yilai; Li, Jianwei; Li, Guichun; Hu, Xiaomin

    2016-06-17

    We examined community diversity, structure and carbon footprint of nematode food web along a chronosequence of T. Sinensis reforestation on degraded Karst. In general, after the reforestation: a serious of diversity parameters and community indices (Shannon-Weinier index (H'), structure index (SI), etc.) were elevated; biomass ratio of fungivores to bacterivores (FFC/BFC), and fungi to bacteria (F/B) were increased, and nematode channel ratio (NCR) were decreased; carbon footprints of all nematode trophic groups, and biomass of bacteria and fungi were increased. Our results indicate that the Karst aboveground vegetation restoration was accompanied with belowground nematode food web development: increasing community complexity, function and fungal dominance in decomposition pathway, and the driving forces included the bottom-up effect (resource control), connectedness of functional groups, as well as soil environments.

  1. Community diversity, structure and carbon footprint of nematode food web following reforestation on degraded Karst soil

    PubMed Central

    Hu, Ning; Li, Hui; Tang, Zheng; Li, Zhongfang; Tian, Jing; Lou, Yilai; Li, Jianwei; Li, Guichun; Hu, Xiaomin

    2016-01-01

    We examined community diversity, structure and carbon footprint of nematode food web along a chronosequence of T. Sinensis reforestation on degraded Karst. In general, after the reforestation: a serious of diversity parameters and community indices (Shannon-Weinier index (H′), structure index (SI), etc.) were elevated; biomass ratio of fungivores to bacterivores (FFC/BFC), and fungi to bacteria (F/B) were increased, and nematode channel ratio (NCR) were decreased; carbon footprints of all nematode trophic groups, and biomass of bacteria and fungi were increased. Our results indicate that the Karst aboveground vegetation restoration was accompanied with belowground nematode food web development: increasing community complexity, function and fungal dominance in decomposition pathway, and the driving forces included the bottom-up effect (resource control), connectedness of functional groups, as well as soil environments. PMID:27311984

  2. The occurrence of coliform bacteria in the cave waters of Slovak Karst, Slovakia.

    PubMed

    Seman, Milan; Gaálová, Barbora; Cíchová, Marianna; Prokšová, Miloslava; Haviarová, Dagmar; Fľaková, Renáta

    2015-05-01

    The diversity and abundance of coliform bacteria (taxonomically enterobacterias), an important quality water indicator, were determined for four representative caves in Slovak Karst: Domica Cave, Gombasecká Cave, Milada Cave and Krásnohorská Cave. Three hundred and fifty-two enterobacterial isolates were successfully identified by biochemical testing (commercial ENTEROtest 24) and selected isolates confirmed by molecular techniques (PCR, 16S rDNA sequence analysis). A total of 39 enterobacterial species were isolated from cave waters, with predominance of Escherichia coli, Serratia spp. and Enterobacter spp. PCR amplification of lacZ gene is not specific enough to provide a reliable detection of coliform bacteria isolated from the environment. Sequence analysis of 16S rDNA confirmed that all of the selected isolates belong to the family Enterobacteriaceae. In general, physical and chemical parameters of cave waters in Slovak Karst corresponded to national drinking water quality standards.

  3. Preliminary conceptual models of the occurrence, fate, and transport of chlorinated solvents in karst regions of Tennessee

    USGS Publications Warehouse

    Wolfe, W.J.; Haugh, C.J.; Webbers, Ank; Diehl, T.H.

    1997-01-01

    Published and unpublished reports and data from 22 contaminated sites in Tennessee were reviewed to develop preliminary conceptual models of the behavior of chlorinated solvents in karst aquifers. Chlorinated solvents are widely used in many industrial operations. High density and volatility, low viscosity, and solubilities that are low in absolute terms but high relative to drinkingwater standards make chlorinated solvents mobile and persistent contaminants that are difficult to find or remove when released into the groundwater system. The major obstacle to the downward migration of chlorinated solvents in the subsurface is the capillary pressure of small openings. In karst aquifers, chemical dissolution has enlarged joints, bedding planes, and other openings that transmit water. Because the resulting karst conduits are commonly too large to develop significant capillary pressures, chlorinated solvents can migrate to considerable depth in karst aquifers as dense nonaqueous-phase liquids (DNAPL?s). Once chlorinated DNAPL accumulates in a karst aquifer, it becomes a source for dissolved-phase contamination of ground water. A relatively small amount of chlorinated DNAPL has the potential to contaminate ground water over a significant area for decades or longer. Conceptual models are needed to assist regulators and site managers in characterizing chlorinated-solvent contamination in karst settings and in evaluating clean-up alternatives. Five preliminary conceptual models were developed, emphasizing accumulation sites for chlorinated DNAPL in karst aquifers. The models were developed for the karst regions of Tennessee, but are intended to be transferable to similar karst settings elsewhere. The five models of DNAPL accumulation in karst settings are (1) trapping in regolith, (2) pooling at the top of bedrock, (3) pooling in bedrock diffuse-flow zones, (4) pooling in karst conduits, and (5) pooling in isolation from active ground-water flow. More than one conceptual

  4. Molecular systematics of the Labeonini inhabiting the karst regions in southwest China (Teleostei, Cypriniformes).

    PubMed

    Zheng, Lan-Ping; Chen, Xiao-Yong; Yang, Jun-Xing

    2016-01-01

    The major phylogenetic pattern of the cyprinid tribe Labeonini has been revealed by previous molecular studies; however, the relationships within a clade that mainly inhabits the karst regions, which we refer to as the "karst group", in southwest China remain unresolved due to the low taxon sampling. This group includes more than 50% of the genera and species of Labeonini in China. Moreover, more than 90% of the genera of this group are endemic to China. In addition, some new genera and species of Labeonini have been discovered from these karst regions, but their taxonomic validity and phylogenetic position have not been examined. In this contribution, partial sequences of four nuclear (exon 3 of recombination activating protein 1, rhodopsin, early growth response protein 2B gene and interphotoreceptor retinoid binding protein gene) and three mitochondrial genes (cytochrome b, cytochrome oxidase subunit I and 16S ribosomal RNA) from 36 ingroup taxa and 25 outgroup taxa were analyzed to provide a hypothesis of the phylogenetic relationships within the labeonins of the karst regions in China. We propose that the monophyly of Parasinilabeo, Ptychidio, Rectoris and Semilabeo are supported. A new genus, Prolixicheilus, is erected for Pseudogyrinocheilus longisulcus. Cophecheilus bamen is the sister to Prolixicheilus longisulcus. Ptychidio, Pseudocrossocheilus, Semilabeo, Rectoris and Stenorynchoacrum are closely related with high support values. Sinocrossocheilus, Pseudogyrinocheilus, Paraqianlabeo, Hongshuia, Discogobio and Discocheilus form a clade together with high support. Considering molecular results and morphological differences, Parasinilabeo longicorpus and Ptychidio macrops might be the synonyms of Parasinilabeo assimilis and Ptychidio jordani respectively. Comprehensive taxonomic revisions of the two genera Parasinilabeo and Ptychidio may be necessary. PMID:27667927

  5. Chemical Source Tracking of Bacterial Contamination Using Micropollutants - A Karst Aquifer Case Study

    NASA Astrophysics Data System (ADS)

    Zirlewagen, Johannes; Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Schiperski, Ferry; Stange, Claudia; Tiehm, Andreas; Scheytt, Traugott

    2015-04-01

    Karst aquifers are important drinking water resources in many parts of the world, though they are well known for their high vulnerability to contamination. Rainfall and snowmelt often trigger temporary contamination of karst water resources. Free-range animal breeding and application of manure on the one hand and sewage leakage or spillage on the other hand are usually regarded as main sources for fecal contamination. But distinction of their respective contributions is difficult. This study investigates the feasibility to track the origin of fecal contamination from the occurrences of indicator bacteria and chemical source indicators in karst spring water. The study site is the 45 km² rural catchment of the perennial karst spring Gallusquelle in SW-Germany (mean discharge: 0.5 m³/s). Overflow events of a stormwater detention basin (combined sewer system) are known to impact water quality at the spring. There is no free-range animal breeding in the catchment but intense application of manure. Following two heavy rainfall events with overflow of the stormwater detention basin, spring water was sampled over several days. Samples were analysed for indicator bacteria (total Coliform, E. coli, Enterococci) and 57 micropollutants, among them cyclamate and metazachlor. For the Gallusquelle catchment the artificial sweetener cyclamate and the herbicide metazachlor have been established as source specific indicators, the former for the sewer system and the latter for cropland. Though recharge in the Gallusquelle catchment is predominantly diffuse, there is a significant portion of direct recharge reflected by distinct breakthrough curves for cyclamate and metazachlor. The breakthrough of indicator bacteria coincides very well with the occurrence of both, cyclamate and metazachlor. However, indicator bacteria cannot be unambiguously tracked back to a specific source.

  6. Changes in groundwater quality in a conduit-flow-dominated karst aquifer, following BMP implementation

    USGS Publications Warehouse

    Currens, J.C.

    2002-01-01

    Water quality in the Pleasant Grove Spring karst groundwater basin, Logan County, Kentucky, was monitored to determine the effectiveness of best management practices (BMPs) in protecting karst aquifers. Ninety-two percent of the 4,069-ha (10,054-acre) watershed is used for agriculture. Water-quality monitoring began in October 1992 and ended in November 1998. By the fall of 1995 approximately 72% of the watershed was enrolled in BMPs sponsored by the US Department of Agriculture Water Quality Incentive Program (WQIP). Pre-BMP nitrate-nitrogen concentration averaged 4.65 mg/1. The median total suspended solids concentration was 127 mg/1. The median triazine concentration measured by immunosorbent assay was 1.44 ??tg/l. Median bacteria counts were 418 colonies per 100 ml (col/100 ml) for fecal coliform and 540 col/100 ml for fecal streptococci. Post-BMP, the average nitrate-nitrogen concentration was 4.74 mg/1. The median total suspended solids concentration was 47.8 mg/1. The median triazine concentration for the post-BMP period was 1.48 ??g/1. The median fecal coliform count increased to 432 col/100 ml after BMP implementation, but the median fecal streptococci count decreased to 441 col/100 ml. The pre- and post-BMP water quality was statistically evaluated by comparing the annual mass flux, annual descriptive statistics, and population of analyses for the two periods. Nitrate-nitrogen concentration was unchanged. Increases in atrazine-equivalent flux and triazine geometric averages were not statistically significant. Total suspended solids concentration decreased slightly, whereas orthophosphate concentration increased slightly. Fecal streptococci counts were reduced. The BMPs were only partially successful because the types available and the rules for participation resulted in less effective BMPs being chosen. Future BMP programs in karst areas should emphasize buffer strips around sinkholes, excluding livestock from streams and karst windows, and withdrawing

  7. Evaluating susceptibility of karst dolines (sinkholes) for collapse in Sango, Tennessee, USA

    PubMed Central

    Siska, Peter P.; Goovaerts, Pierre; Hung, I-K

    2016-01-01

    Dolines or sinkholes are earth depressions that develop in soluble rocks complexes such as limestone, dolomite, gypsum, anhydrite, and halite; dolines appear in a variety of shapes from nearly circular to complex structures with highly curved perimeters. The occurrence of dolines in the studied karst area is not random; they are the results of geomorphic, hydrologic, and chemical processes that have caused partial subsidence, even the total collapse of the land surface when voids and caves are present in the bedrock and the regolith arch overbridging these voids is unstable. In the study area, the majority of collapses occur in the regolith (bedrock cover) that bridges voids in the bedrock. Because these collapsing dolines may result in property damage and even cause the loss of lives, there is a need to develop methods for evaluating karst hazards. These methods can then be used by planners and practitioners for urban and economic development, especially in regions with a growing population. The purpose of this project is threefold: 1) to develop a karst feature database, 2) to investigate critical indicators associated with doline collapse, and 3) to develop a doline susceptibility model for potential doline collapse based on external morphometric data. The study has revealed the presence of short range spatial dependence in the distribution of the dolines’ morphometric parameters such as circularity, the geographic orientation of the main doline axes, and the length-to-width doline ratios; therefore, geostatistics can be used to spatially evaluate the susceptibility of the karst area for doline collapse. The partial susceptibility estimates were combined into a final probability map enabling the identification of areas where, until now, undetected dolines may cause significant hazards. PMID:27616807

  8. Transport of antibiotic-resistant Escherichia coli in a public rural karst water supply

    NASA Astrophysics Data System (ADS)

    Laroche, Emilie; Petit, Fabienne; Fournier, Matthieu; Pawlak, Barbara

    2010-10-01

    SummaryThe goal of this study was to determine the conditions promoting the transport of antibiotic-resistant faecal bacteria, in a rural karst system providing drinking water (Northwest France). For this purpose, the resistance of the Escherichia coli population (436 isolates) to 17 antibiotics was investigated by analysing water samples from four representative interconnected sites: a creek, a swallow hole, a spring, and a well. The samples were collected during four contrasting hydrologic and grazing periods. The transport of resistant E. coli from the creek to the well appeared to be dominated by run-off and leaching phenomena. Less than 7% of the E. coli isolated during a wet period without grazing or during a dry period with grazing were antibiotic-resistant, whereas, during rainfall events with grazing, between 30% and 55% of the E. coli detected were resistant; 10-23% of these isolates were resistant to two or three antibiotics. The resistance most often found was to either chloramphenicol or tetracycline. To better describe the dynamics of the antibiotic-resistant population of E. coli entering the karst aquifer, the swallow hole was monitored over a 24-h period during a rainfall event (90 isolates). The antibiotic resistance of E. coli isolates and the occurrence of class 1 integrons, genetic elements involved multi-resistance, were determined. The origin of this E. coli population was also investigated. This monitoring demonstrated that multi-antibiotic-resistant E. coli, representing 23% of the total population, infiltrated the karst aquifer at the peak of a rainfall event, with some isolates being resistant to up to eight antibiotics. No intI1 gene was detected. The search for the origin of the resistant E. coli isolated during this rainfall event demonstrated that they were of both animal and human origin. This work demonstrates that drinking water resources taken from the groundwater in a rural karst terrain is vulnerable to contamination by

  9. River Intrusion in Karst Springs in Eogenetic Aquifers: Implications for Speleogenesis

    NASA Astrophysics Data System (ADS)

    Martin, J. B.; Gulley, J.; Screaton, E. J.

    2008-12-01

    Conceptual models of speleogenesis generally assume uni-directional transport in integrated conduit systems from discrete recharge points to discharge at karst springs. Estavelles, however, are karst springs that function intermittently as discrete recharge points when river stage rises more rapidly than local aquifer heads. As river water chemistry changes between baseflow and floods, estavelles should influence mass transport through (e.g. organic carbon, nutrients, and oxygen) and speleogenesis within karst systems. Estavelles are common in our study area in north-central Florida, particularly along the lower reaches of the Santa Fe River, where it flows across the unconfined karstic Floridan aquifer. River stage in this unconfined region can rise much faster than aquifer heads when large amounts of rain fall on the confined regions in its upper reaches. Backflooding into the estavelles during elevated river stage drives river water into the ground, causing some springs to reverse and other springs to recirculate large volumes of river water. Floodwaters originating in the confined region are highly undersaturated with respect to calcite, and thus river water transitions from slightly supersaturated to highly undersaturated with respect to calcite during flood events. As a result, conduits connected to estavelles are continuously enlarged as springs reverse or recirculate calcite-undersaturated river water. It has been suggested that currently flooded caves (i.e. karst conduits) associated with springs in Florida formed entirely underwater because speleothems, which are prevalent in flooded caves in the Yucatan and Bahamas, have not been observed by cave divers. Results of this study indicate that the absence of speleothems does not necessarily provide evidence of a continuous phreatic history for underwater caves. Instead speleothems that formed in caves while dry could have been dissolved by backflooding of estavelles with undersaturated water

  10. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.

    PubMed

    Musgrove, M; Opsahl, S P; Mahler, B J; Herrington, C; Sample, T L; Banta, J R

    2016-10-15

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3(-)) loading to surface and groundwater. We investigate variability and sources of NO3(-) in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008-12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3(-) stable isotopes (δ(15)N and δ(18)O). These data were augmented by historical data collected from 1937 to 2007. NO3(-) concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3(-) concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3(-) concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3(-). These results highlight the vulnerability of karst aquifers to NO3(-) contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008-10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3(-) than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously unrecognized

  11. Multitracer experiment to evaluate the attenuation of selected organic micropollutants in a karst aquifer.

    PubMed

    Hillebrand, Olav; Nödler, Karsten; Sauter, Martin; Licha, Tobias

    2015-02-15

    The increasing pressure on drinking water resources necessitates an efficient management of potential and actual drinking water resources. Karst aquifers play a key role in the supply of the world's population with drinking water. Around one quarter of all drinking water is produced from these types of aquifers. Unfortunately due to the aquifer characteristics with extremely high hydraulic conductivities and short residence times, these systems are vulnerable to contamination. For successful management, a fundamental understanding of mass transport and attenuation processes with respect to potential contaminants is vital. In this study, a multitracer experiment was performed in a karst aquifer in SW-Germany for determining the attenuation capacity of a karst environment by assessing the environmental fate of selected relevant micropollutants. Uranine, acesulfame and carbamazepine were injected into a sinkhole as reference tracers together with the reactive compounds atenolol, caffeine, cyclamate, ibuprofen and paracetamol (also known as acetaminophen). The breakthrough of the tracers was monitored at a karst spring at a distance of ca. 3 km. The breakthrough curves of the reactive compounds were interpreted relative to the reference substances. No significant retardation was found for any of the investigated micropollutants. The determined half-lives of the reactive compounds range from 38 to 1,400 h (i.e. persistent within the investigation period) in the following order (from high to no observed attenuation): paracetamol>atenolol≈ibuprofen>caffeine≫cyclamate. The attenuation rates are generally in agreement with studies from other environmental compartments. The occurrence of the biotransformation product atenolol acid served as evidence for in-situ biodegradation within the aquifer system.

  12. Molecular systematics of the Labeonini inhabiting the karst regions in southwest China (Teleostei, Cypriniformes).

    PubMed

    Zheng, Lan-Ping; Chen, Xiao-Yong; Yang, Jun-Xing

    2016-01-01

    The major phylogenetic pattern of the cyprinid tribe Labeonini has been revealed by previous molecular studies; however, the relationships within a clade that mainly inhabits the karst regions, which we refer to as the "karst group", in southwest China remain unresolved due to the low taxon sampling. This group includes more than 50% of the genera and species of Labeonini in China. Moreover, more than 90% of the genera of this group are endemic to China. In addition, some new genera and species of Labeonini have been discovered from these karst regions, but their taxonomic validity and phylogenetic position have not been examined. In this contribution, partial sequences of four nuclear (exon 3 of recombination activating protein 1, rhodopsin, early growth response protein 2B gene and interphotoreceptor retinoid binding protein gene) and three mitochondrial genes (cytochrome b, cytochrome oxidase subunit I and 16S ribosomal RNA) from 36 ingroup taxa and 25 outgroup taxa were analyzed to provide a hypothesis of the phylogenetic relationships within the labeonins of the karst regions in China. We propose that the monophyly of Parasinilabeo, Ptychidio, Rectoris and Semilabeo are supported. A new genus, Prolixicheilus, is erected for Pseudogyrinocheilus longisulcus. Cophecheilus bamen is the sister to Prolixicheilus longisulcus. Ptychidio, Pseudocrossocheilus, Semilabeo, Rectoris and Stenorynchoacrum are closely related with high support values. Sinocrossocheilus, Pseudogyrinocheilus, Paraqianlabeo, Hongshuia, Discogobio and Discocheilus form a clade together with high support. Considering molecular results and morphological differences, Parasinilabeo longicorpus and Ptychidio macrops might be the synonyms of Parasinilabeo assimilis and Ptychidio jordani respectively. Comprehensive taxonomic revisions of the two genera Parasinilabeo and Ptychidio may be necessary.

  13. Using MODFLOW drains to simulate groundwater flow in a karst environment

    SciTech Connect

    Quinn, J.; Tomasko, D.; Glennon, M.A.; Miller, S.F.; McGinnis, L.D.

    1998-07-01

    Modeling groundwater flow in a karst environment is both numerically challenging and highly uncertain because of potentially complex flowpaths and a lack of site-specific information. This study presents the results of MODFLOW numerical modeling in which drain cells in a finite-difference model are used as analogs for preferential flowpaths or conduits in karst environments. In this study, conduits in mixed-flow systems are simulated by assigning connected pathways of drain cells from the locations of tracer releases, sinkholes, or other karst features to outlet springs along inferred flowpaths. These paths are determined by the locations of losing stream segments, ephemeral stream beds, geophysical surveys, fracture lineaments, or other surficial characteristics, combined with the results of dye traces. The elevations of the drains at the discharge ends of the inferred flowpaths are estimated from field data and are adjusted when necessary during model calibration. To simulate flow in a free-flowing conduit, a high conductance is assigned to each drain to eliminate the need for drain-specific information that would be very difficult to obtain. Calculations were performed for a site near Hohenfels, Germany. The potentiometric surface produced by the simulations agreed well with field data. The head contours in the vicinity of the karst features behaved in a manner consistent with a flow system having both diffuse and conduit components, and the sum of the volumetric flow out of the drain cells agreed closely with spring discharges and stream flows. Because of the success of this approach, it is recommended for regional studies in which little site-specific information (e.g., location, number, size, and conductivity of fractures and conduits) is available, and general flow characteristics are desired.

  14. Molecular systematics of the Labeonini inhabiting the karst regions in southwest China (Teleostei, Cypriniformes)

    PubMed Central

    Zheng, Lan-Ping; Chen, Xiao-Yong; Yang, Jun-Xing

    2016-01-01

    Abstract The major phylogenetic pattern of the cyprinid tribe Labeonini has been revealed by previous molecular studies; however, the relationships within a clade that mainly inhabits the karst regions, which we refer to as the “karst group”, in southwest China remain unresolved due to the low taxon sampling. This group includes more than 50% of the genera and species of Labeonini in China. Moreover, more than 90% of the genera of this group are endemic to China. In addition, some new genera and species of Labeonini have been discovered from these karst regions, but their taxonomic validity and phylogenetic position have not been examined. In this contribution, partial sequences of four nuclear (exon 3 of recombination activating protein 1, rhodopsin, early growth response protein 2B gene and interphotoreceptor retinoid binding protein gene) and three mitochondrial genes (cytochrome b, cytochrome oxidase subunit I and 16S ribosomal RNA) from 36 ingroup taxa and 25 outgroup taxa were analyzed to provide a hypothesis of the phylogenetic relationships within the labeonins of the karst regions in China. We propose that the monophyly of Parasinilabeo, Ptychidio, Rectoris and Semilabeo are supported. A new genus, Prolixicheilus, is erected for Pseudogyrinocheilus longisulcus. Cophecheilus bamen is the sister to Prolixicheilus longisulcus. Ptychidio, Pseudocrossocheilus, Semilabeo, Rectoris and Stenorynchoacrum are closely related with high support values. Sinocrossocheilus, Pseudogyrinocheilus, Paraqianlabeo, Hongshuia, Discogobio and Discocheilus form a clade together with high support. Considering molecular results and morphological differences, Parasinilabeo longicorpus and Ptychidio macrops might be the synonyms of Parasinilabeo assimilis and Ptychidio jordani respectively. Comprehensive taxonomic revisions of the two genera Parasinilabeo and Ptychidio may be necessary. PMID:27667927

  15. Soil bacterial community composition and diversity respond to cultivation in Karst ecosystems.

    PubMed

    Chen, Xiangbi; Su, Yirong; He, Xunyang; Wei, Yawei; Wei, Wenxue; Wu, Jinshui

    2012-01-01

    Soil microorganisms play vital roles in recovering and maintaining the health of ecosystems, particularly in fragile Karst ecosystems that are easily degraded after cultivation. We investigated the composition and diversity of soil bacterial communities, based on RFLP and 16S rDNA sequencing, in a cropland, a naturally revegetated land with former cultivation disturbance and a primeval forest in the subtropical Karst of southwest China. Our results illustrated that Proteobacteria accounted for 44.8% of the 600 tested clones, making it the most dominant phylum observed. This phylum was followed by Acidobacteria and Planctomycetes for the three Karst soils analyzed. Compared with the primeval forest soil, the proportions of Proteobacteria were decreased by 30.2 and 37.9%, while Acidobacteria increased by 93.9 and 87.9%, and the Shannon-Wiener diversity indices and the physicochemical parameters declined in the cropland and the revegetated land, respectively. Among the three soils, the proportion of dominant bacterial phyla and the diversity indices in the revegetated land were similar to the cropland, implying the bacterial community in the cropland was relatively stable, and the after-effects of cultivation were difficult to eliminate. However, similar distributions of the four Proteobacteria subphyla were observed between the revegetated land and the primeval forest soil. Furthermore, the proportion of Rhizobiales belonging to α-Proteobacteria was sharply decreased with cultivation compared to the primeval forest soil, while a small cluster of Rhizobiales recurred with vegetation recovery. These results indicated that although the subphyla of the dominant bacterial phylum had some positive responses to 20 years of vegetation recovery, it is a slow process. Our results suggest that priority should be given to conserve the primeval forest and inoculation of functional microorganisms on the basis of vegetation recovery may be more effective for the restoration of

  16. Possible conduit-matrix water exchange signatures outlined at a karst spring.

    PubMed

    Mitrofan, Horia; Marin, Constantin; Povară, Ioan

    2015-04-01

    During a significant flood event, reversible water exchanges may occur between a karst conduit and its adjacent porous rock (frequently designated as "matrix"): while the flood pulse rises, some conduit-derived water is forced into the matrix; then, as the flood recedes, the same water flows back into the stream passage. The present note addresses such a karst setting in the Carpathian Mountains (Romania), where in addition, a usually stable flux of chloride originating in a natural saline inflow, was being mixed with a variable flow of karst freshwater. For that particular case, with the above-mentioned process of matrix storage/release from storage assumedly taking place downstream of the mixing site, two distinct chemical signatures could be noticed during a flood event: an initial depletion in the spring flow chloride flux, subsequently followed by a comparable chloride flux enrichment (the depletion and the enrichment being outlined with respect to the essentially stable chloride flux value that had been noticed to persist at the spring over a long period of flow rate recession). Concomitantly with such flood-induced fluctuations in the spring chloride flux, the spring discharge displayed, for long periods, abnormally slow variations: the latter likely indicated that the spring supply rate actual oscillations were buffered by the reversible water exchanges which took place between the karst conduit and its adjacent matrix. On the whole, these results show that conduit-matrix water exchanges could be interpreted by simple mass balance calculations that involved fluxes of a conservative tracer (the chloride ion in that particular case).

  17. Effects of dynamically variable saturation and matrix-conduit coupling of flow in karst aquifers

    USGS Publications Warehouse

    Reimann, T.; Geyer, T.; Shoemaker, W.B.; Liedl, R.; Sauter, M.

    2011-01-01

    Well-developed karst aquifers consist of highly conductive conduits and a relatively low permeability fractured and/or porous rock matrix and therefore behave as a dual-hydraulic system. Groundwater flow within highly permeable strata is rapid and transient and depends on local flow conditions, i.e., pressurized or nonpressurized flow. The characterization of karst aquifers is a necessary and challenging task because information about hydraulic and spatial conduit properties is poorly defined or unknown. To investigate karst aquifers, hydraulic stresses such as large recharge events can be simulated with hybrid (coupled discrete continuum) models. Since existing hybrid models are simplifications of the system dynamics, a new karst model (ModBraC) is presented that accounts for unsteady and nonuniform discrete flow in variably saturated conduits employing the Saint-Venant equations. Model performance tests indicate that ModBraC is able to simulate (1) unsteady and nonuniform flow in variably filled conduits, (2) draining and refilling of conduits with stable transition between free-surface and pressurized flow and correct storage representation, (3) water exchange between matrix and variably filled conduits, and (4) discharge routing through branched and intermeshed conduit networks. Subsequently, ModBraC is applied to an idealized catchment to investigate the significance of free-surface flow representation. A parameter study is conducted with two different initial conditions: (1) pressurized flow and (2) free-surface flow. If free-surface flow prevails, the systems is characterized by (1) a time lag for signal transmission, (2) a typical spring discharge pattern representing the transition from pressurized to free-surface flow, and (3) a reduced conduit-matrix interaction during free-surface flow. Copyright 2011 by the American Geophysical Union.

  18. Karst-controlled reservoir heterogeneity in Ellenburger group carbonates of west Texas

    SciTech Connect

    Kerans, C.

    1988-10-01

    Petroleum production from restricted shelf carbonates of the Lower Ordovician Ellenburger group is commonly considered to have been a result of a pervasive, relatively homogeneous tectonic fracture system within the reservoir rock. However, regional facies and diagenetic (paleokarst) studies of Ellenburger strata, based on cores and wireline logs, have demonstrated that significant reservoir compartmentalization was caused by karst modification in the upper part of the unit. 19 figures.

  19. Enhanced Nitrogen Availability in Karst Ecosystems by Oxalic Acid Release in the Rhizosphere.

    PubMed

    Pan, Fujing; Liang, Yueming; Zhang, Wei; Zhao, Jie; Wang, Kelin

    2016-01-01

    In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM) and causes nitrogen (N) and/or phosphorus (P) limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015) where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass carbon (MBC), and β-1,4-N-acetylglucosaminidase (NAG) on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees) in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems.

  20. Multitracer experiment to evaluate the attenuation of selected organic micropollutants in a karst aquifer.

    PubMed

    Hillebrand, Olav; Nödler, Karsten; Sauter, Martin; Licha, Tobias

    2015-02-15

    The increasing pressure on drinking water resources necessitates an efficient management of potential and actual drinking water resources. Karst aquifers play a key role in the supply of the world's population with drinking water. Around one quarter of all drinking water is produced from these types of aquifers. Unfortunately due to the aquifer characteristics with extremely high hydraulic conductivities and short residence times, these systems are vulnerable to contamination. For successful management, a fundamental understanding of mass transport and attenuation processes with respect to potential contaminants is vital. In this study, a multitracer experiment was performed in a karst aquifer in SW-Germany for determining the attenuation capacity of a karst environment by assessing the environmental fate of selected relevant micropollutants. Uranine, acesulfame and carbamazepine were injected into a sinkhole as reference tracers together with the reactive compounds atenolol, caffeine, cyclamate, ibuprofen and paracetamol (also known as acetaminophen). The breakthrough of the tracers was monitored at a karst spring at a distance of ca. 3 km. The breakthrough curves of the reactive compounds were interpreted relative to the reference substances. No significant retardation was found for any of the investigated micropollutants. The determined half-lives of the reactive compounds range from 38 to 1,400 h (i.e. persistent within the investigation period) in the following order (from high to no observed attenuation): paracetamol>atenolol≈ibuprofen>caffeine≫cyclamate. The attenuation rates are generally in agreement with studies from other environmental compartments. The occurrence of the biotransformation product atenolol acid served as evidence for in-situ biodegradation within the aquifer system. PMID:25460968

  1. Enhanced Nitrogen Availability in Karst Ecosystems by Oxalic Acid Release in the Rhizosphere

    PubMed Central

    Pan, Fujing; Liang, Yueming; Zhang, Wei; Zhao, Jie; Wang, Kelin

    2016-01-01

    In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM) and causes nitrogen (N) and/or phosphorus (P) limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015) where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass carbon (MBC), and β-1,4-N-acetylglucosaminidase (NAG) on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees) in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems. PMID:27252713

  2. Evaluating susceptibility of karst dolines (sinkholes) for collapse in Sango, Tennessee, USA

    PubMed Central

    Siska, Peter P.; Goovaerts, Pierre; Hung, I-K

    2016-01-01

    Dolines or sinkholes are earth depressions that develop in soluble rocks complexes such as limestone, dolomite, gypsum, anhydrite, and halite; dolines appear in a variety of shapes from nearly circular to complex structures with highly curved perimeters. The occurrence of dolines in the studied karst area is not random; they are the results of geomorphic, hydrologic, and chemical processes that have caused partial subsidence, even the total collapse of the land surface when voids and caves are present in the bedrock and the regolith arch overbridging these voids is unstable. In the study area, the majority of collapses occur in the regolith (bedrock cover) that bridges voids in the bedrock. Because these collapsing dolines may result in property damage and even cause the loss of lives, there is a need to develop methods for evaluating karst hazards. These methods can then be used by planners and practitioners for urban and economic development, especially in regions with a growing population. The purpose of this project is threefold: 1) to develop a karst feature database, 2) to investigate critical indicators associated with doline collapse, and 3) to develop a doline susceptibility model for potential doline collapse based on external morphometric data. The study has revealed the presence of short range spatial dependence in the distribution of the dolines’ morphometric parameters such as circularity, the geographic orientation of the main doline axes, and the length-to-width doline ratios; therefore, geostatistics can be used to spatially evaluate the susceptibility of the karst area for doline collapse. The partial susceptibility estimates were combined into a final probability map enabling the identification of areas where, until now, undetected dolines may cause significant hazards.

  3. Groundwater balance estimation in karst by using simple conceptual rainfall-runoff model

    NASA Astrophysics Data System (ADS)

    Željković, Ivana; Kadić, Ana; Denić-Jukić, Vesna

    2014-05-01

    The objective of this work is the study of Opačac karst spring which geographically lies in Dalmatia (Croatia). Numerous studies have been carried out in karst aiming the investigation of groundwater regime. The karst spring hydrograph can reflect the groundwater regime and consequently the analysis is based on them. A simple conceptual rainfall-runoff model is proposed for the estimation of groundwater balance components including the influences of time invariant catchment boundaries and intercatchment flows. The proposed parameter estimation procedure merges the soil-moisture balance and the groundwater balance approaches to obtain the complete groundwater budget. The effective rainfall is calculated by using mathematical model based on soil-moisture balance equations i.e. Palmer's fluid mass balance method. The parameters of model of effective rainfall are determined by using simple conceptual rainfall-runoff model consisting of two linear reservoirs representing the fast and slow flow component of the recession. The weight coefficient between the fast and slow component is determined by using BFI (Base Flow Index) analysis of hydrograph. Recession coefficient of the slow flow component and the weight coefficient are determined from hydrograph analysis. Available data from nearby meteorological station includes on daily basis daily average discharge, the amount of precipitation, the average temperature and the humidity from 1995-2010. The average catchment area is also estimated with the average yearly runoff deficit using Turc's method and compared with the values obtained from the application of the rainfall-runoff model. Nash-Sutcliffe model efficiency coefficient for simulated hydrograph is applied to assess the predictive power of model. Calculated groundwater balance shows that the Opačac Spring aquifer contains a significant storage capacity. The application of series of linear reservoirs is a classical and common technique, but the proposed simple

  4. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.

    PubMed

    Musgrove, M; Opsahl, S P; Mahler, B J; Herrington, C; Sample, T L; Banta, J R

    2016-10-15

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3(-)) loading to surface and groundwater. We investigate variability and sources of NO3(-) in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008-12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3(-) stable isotopes (δ(15)N and δ(18)O). These data were augmented by historical data collected from 1937 to 2007. NO3(-) concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3(-) concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3(-) concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3(-). These results highlight the vulnerability of karst aquifers to NO3(-) contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008-10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3(-) than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously unrecognized

  5. Molecular systematics of the Labeonini inhabiting the karst regions in southwest China (Teleostei, Cypriniformes)

    PubMed Central

    Zheng, Lan-Ping; Chen, Xiao-Yong; Yang, Jun-Xing

    2016-01-01

    Abstract The major phylogenetic pattern of the cyprinid tribe Labeonini has been revealed by previous molecular studies; however, the relationships within a clade that mainly inhabits the karst regions, which we refer to as the “karst group”, in southwest China remain unresolved due to the low taxon sampling. This group includes more than 50% of the genera and species of Labeonini in China. Moreover, more than 90% of the genera of this group are endemic to China. In addition, some new genera and species of Labeonini have been discovered from these karst regions, but their taxonomic validity and phylogenetic position have not been examined. In this contribution, partial sequences of four nuclear (exon 3 of recombination activating protein 1, rhodopsin, early growth response protein 2B gene and interphotoreceptor retinoid binding protein gene) and three mitochondrial genes (cytochrome b, cytochrome oxidase subunit I and 16S ribosomal RNA) from 36 ingroup taxa and 25 outgroup taxa were analyzed to provide a hypothesis of the phylogenetic relationships within the labeonins of the karst regions in China. We propose that the monophyly of Parasinilabeo, Ptychidio, Rectoris and Semilabeo are supported. A new genus, Prolixicheilus, is erected for Pseudogyrinocheilus longisulcus. Cophecheilus bamen is the sister to Prolixicheilus longisulcus. Ptychidio, Pseudocrossocheilus, Semilabeo, Rectoris and Stenorynchoacrum are closely related with high support values. Sinocrossocheilus, Pseudogyrinocheilus, Paraqianlabeo, Hongshuia, Discogobio and Discocheilus form a clade together with high support. Considering molecular results and morphological differences, Parasinilabeo longicorpus and Ptychidio macrops might be the synonyms of Parasinilabeo assimilis and Ptychidio jordani respectively. Comprehensive taxonomic revisions of the two genera Parasinilabeo and Ptychidio may be necessary.

  6. Enhanced Nitrogen Availability in Karst Ecosystems by Oxalic Acid Release in the Rhizosphere.

    PubMed

    Pan, Fujing; Liang, Yueming; Zhang, Wei; Zhao, Jie; Wang, Kelin

    2016-01-01

    In karst ecosystems, a high level of CaCO3 enhances the stabilization of soil organic matter (SOM) and causes nitrogen (N) and/or phosphorus (P) limitation in plants. Oxalic acid has been suggested to be involved in the nutrient-acquisition strategy of plants because its addition can temporarily relieve nutrient limitation. Therefore, understanding how oxalic acid drives N availability may help support successful vegetation restoration in the karst ecosystems of southwest China. We tested a model suggested by Clarholm et al. (2015) where oxalate reacts with Ca bridges in SOM, thus exposing previously protected areas to enzymatic attacks in a way that releases N for local uptake. We studied the effects of oxalic acid, microbial biomass carbon (MBC), and β-1,4-N-acetylglucosaminidase (NAG) on potential N mineralization rates in rhizosphere soils of four plant species (two shrubs and two trees) in karst areas. The results showed that rhizosphere soils of shrubs grown on formerly deforested land had significantly lower oxalic acid concentrations and NAG activity than that of trees in a 200-year-old forest. The levels of MBC in rhizosphere soils of shrubs were significantly lower than those of trees in the growing season, but the measure of shrubs and trees were similar in the non-growing season; the potential N mineralization rates showed a reverse pattern. Positive relationships were found among oxalic acid, MBC, NAG activity, and potential N mineralization rates for both shrubs and trees. This indicated that oxalic acid, microbes, and NAG may enhance N availability for acquisition by plants. Path analysis showed that oxalic acid enhanced potential N mineralization rates indirectly through inducing microbes and NAG activities. We found that the exudation of oxalic acid clearly provides an important mechanism that allows plants to enhance nutrient acquisition in karst ecosystems. PMID:27252713

  7. Evolutionary history of relict Congeria (Bivalvia: Dreissenidae): unearthing the subterranean biodiversity of the Dinaric Karst

    PubMed Central

    2013-01-01

    Background Patterns of biodiversity in the subterranean realm are typically different from those encountered on the Earth’s surface. The Dinaric karst of Croatia, Slovenia and Bosnia and Herzegovina is a global hotspot of subterranean biodiversity. How this was achieved and why this is so remain largely unresolved despite a long tradition of research. To obtain insights into the colonisation of the Dinaric Karst and the effects of the subterranean realm on its inhabitants, we studied the tertiary relict Congeria, a unique cave-dwelling bivalve (Dreissenidae), using a combination of biogeographical, molecular, morphological, and paleontological information. Results Phylogenetic and molecular clock analyses using both nuclear and mitochondrial markers have shown that the surviving Congeria lineage has actually split into three distinct species, i.e., C. kusceri, C. jalzici sp. nov. and C. mulaomerovici sp. nov., by vicariant processes in the late Miocene and Pliocene. Despite millions of years of independent evolution, analyses have demonstrated a great deal of shell similarity between modern Congeria species, although slight differences in hinge plate structure have enabled the description of the two new species. Ancestral plesiomorphic shell forms seem to have been conserved during the processes of cave colonisation and subsequent lineage isolation. In contrast, shell morphology is divergent within one of the lineages, probably due to microhabitat differences. Conclusions Following the turbulent evolution of the Dreissenidae during the Tertiary and major radiations in Lake Pannon, species of Congeria went extinct. One lineage survived, however, by adopting a unique life history strategy that suited it to the underground environment. In light of our new data, an alternative scenario for its colonisation of the karst is proposed. The extant Congeria comprises three sister species that, to date, have only been found to live in 15 caves in the Dinaric karst. Inter

  8. Subsurface flow in a soil-mantled subtropical dolomite karst slope: A field rainfall simulation study

    NASA Astrophysics Data System (ADS)

    Fu, Z. Y.; Chen, H. S.; Zhang, W.; Xu, Q. X.; Wang, S.; Wang, K. L.

    2015-12-01

    Soil and epikarst co-evolve resulting in complex structures, but their coupled structural effects on hydrological processes are poorly understood in karst regions. This study examined the plot-scale subsurface flow characteristics from an integrated soil-epikarst system perspective in a humid subtropical cockpit karst region of Southwest China. A trench was excavated to the epikarst lower boundary for collecting individual subsurface flows in five sections with different soil thicknesses. Four field rainfall simulation experiments were carried out under different initial moisture conditions (dry and wet) and rainfall intensities (114 mm h- 1 (high) and 46 mm h- 1 (low) on average). The soil-epikarst system was characterized by shallow soil overlaying a highly irregular epikarst surface with a near-steady infiltration rate of about 35 mm h- 1. The subsurface flows occurred mainly along the soil-epikarst interface and were dominated by preferential flow. The subsurface flow hydrographs showed strong spatial variability and had high steady-state coefficients (0.52 and 0.36 for high and low rainfall intensity events). Irregular epikarst surface combining with high vertical drainage capacity resulted in high threshold rainfall depths for subsurface flows: 67 mm and 263 mm for initial wet and dry conditions, respectively. The above results evidenced that the irregular and permeable soil-epikarst interface was a crucial component of soil-epikarst architecture and consequently should be taken into account in the hydrological modeling for karst regions.

  9. Modeling spatiotemporal impacts of hydroclimatic extremes on groundwater recharge at a Mediterranean karst aquifer

    NASA Astrophysics Data System (ADS)

    Hartmann, Andreas; Mudarra, Matías; Andreo, Bartolomé; Marín, Ana; Wagener, Thorsten; Lange, Jens

    2014-08-01

    Karst aquifers provide large parts of the water supply for Mediterranean countries, though climate change is expected to have a significant negative impact on water availability. Recharge is therefore a key variable that has to be known for sustainable groundwater use. In this study, we present a new approach that combines two independent methods for karst recharge estimation. The first method derives spatially distributed information of mean annual recharge patterns through GIS analysis. The second is a process-based karst model that provides spatially lumped but temporally distributed information about recharge. By combining both methods, we add a spatial reference to the lumped simulations of the process-based model. In this way, we are able to provide spatiotemporal information of recharge and subsurface flow dynamics also during varying hydroclimatic conditions. We find that there is a nonlinear relationship between precipitation and recharge rates resulting in strong decreases of recharge following even moderate decreases of precipitation. This is primarily due to almost constant actual evapotranspiration amounts despite varying hydroclimatic conditions. During the driest year in the record, almost the entire precipitation was consumed as actual evapotranspiration and only little diffuse recharge took place at the high altitudes of our study site. During wettest year, recharge constituted a much larger fraction of precipitation and occurred at the entire study site. Our new method and our findings are significant for decision makers in similar regions that want to prepare for possible changes of hydroclimatic conditions in the future.

  10. Updating an equivalent porous medium karst aquifer model using the coupled continuum pipe-flow method

    NASA Astrophysics Data System (ADS)

    Saller, S. P.; Ronayne, M. J.; Long, A. J.

    2013-12-01

    Karst conduits are commonly treated as high-conductivity zones in equivalent porous medium (EPM) models. In this study, an EPM model for a Paleozoic age carbonate aquifer was updated to include discrete conduits, and flow was simulated using the coupled continuum pipe-flow method. The modeled area, encompassing 2000 square km of the Madison aquifer in western South Dakota (USA), includes four karst springs with contributing conduit networks. The updated model considered the same observation data that were used to calibrate the EPM model: measured hydraulic heads at matrix observation wells and estimated springflow. Adjusted parameters included the conduit locations and hydraulic properties, as well as the matrix hydraulic conductivity distribution. Inferred karst pathways from environmental tracer analysis were used to guide the placement of conduits. The new coupled continuum pipe-flow model is characterized by a simpler conductivity distribution; extreme high-K values used in the EPM model are not necessary when conduit flow is explicitly simulated. Results are presented to illustrate the influence of conduits on simulated flow behavior.

  11. HISTORICAL CONTAMINATION OF GROUNDWATER RESOURCES IN THE NORTH COAST KARST AQUIFERS OF PUERTO RICO

    PubMed Central

    Padilla, Ingrid; Irizarry, Celys; Steele, Katherine

    2012-01-01

    The North Coast Karst Aquifer System of Puerto Rico is the island’s most productive aquifer. The characteristics that make it highly productive also make it vulnerable to contamination. This research, which addresses the historical contamination of groundwater resources in the northern karst region was conducted through integration of spatial hydrogeologic and contaminant concentration data in the La Plata-Arecibo area. The study used GIS technologies and focused on phthalates and chlorinated volatile organic compounds (CVOCs) and phthalates due to their ubiquitous presence in the environment as well as their presence in listed and potential superfund sites in Puerto Rico and U.S. and potential for exposure and health impacts. Results show an extensive historical contamination of the groundwater resources in the northern karst aquifers. Long-term contamination indicates the aquifers’ large capacity for storing and releasing contaminants and reflects a long-term potential for exposure. The degradation of this important water resource has resulted in a subsequent reduction of the extraction capacity and an increase in the cost of use. PMID:24772197

  12. Hydrogeologic controls on the groundwater interactions with an acidic lake in karst terrain, Lake Barco, Florida

    USGS Publications Warehouse

    Lee, T.M.

    1996-01-01

    Transient groundwater interactions and lake stage were simulated for Lake Barco, an acidic seepage lake in the mantled karst of north central Florida. Karst subsidence features affected groundwater flow patterns in the basin and groundwater fluxes to and from the lake. Subsidence features peripheral to the lake intercepted potential groundwater inflow and increased leakage from the shallow perimeter of the lake bed. Simulated groundwater fluxes were checked against net groundwater flow derived from a detailed lake hydrologic budget with short-term lake evaporation computed by the energy budget method. Discrepancies between modeled and budget- derived net groundwater flows indicated that the model underestimated groundwater inflow, possibly contributed to by transient water table mounding near the lake. Recharge from rainfall reduced lake leakage by 10 to 15 times more than it increased groundwater inflow. As a result of the karst setting, the contributing groundwater basin to the lake was 2.4 ha for simulated average rainfall conditions, compared to the topographically derived drainage basin area of 81 ha. Short groundwater inflow path lines and rapid travel times limit the contribution of acid-neutralizing solutes from the basin, making Lake Barco susceptible to increased acidification by acid rain.

  13. Hydrograph separation for karst watersheds using a two-domain rainfall-discharge model

    USGS Publications Warehouse

    Long, A.J.

    2009-01-01

    Highly parameterized, physically based models may be no more effective at simulating the relations between rainfall and outflow from karst watersheds than are simpler models. Here an antecedent rainfall and convolution model was used to separate a karst watershed hydrograph into two outflow components: one originating from focused recharge in conduits and one originating from slow flow in a porous annex system. In convolution, parameters of a complex system are lumped together in the impulse-response function (IRF), which describes the response of the system to an impulse of effective precipitation. Two parametric functions in superposition approximate the two-domain IRF. The outflow hydrograph can be separated into flow components by forward modeling with isolated IRF components, which provides an objective criterion for separation. As an example, the model was applied to a karst watershed in the Madison aquifer, South Dakota, USA. Simulation results indicate that this watershed is characterized by a flashy response to storms, with a peak response time of 1 day, but that 89% of the flow results from the slow-flow domain, with a peak response time of more than 1 year. This long response time may be the result of perched areas that store water above the main water table. Simulation results indicated that some aspects of the system are stationary but that nonlinearities also exist.

  14. Geologic and anthropogenic factors influencing karst development in the Frederick region of Maryland

    USGS Publications Warehouse

    Brezinski, D.K.

    2007-01-01

    Karst features pervade the outcrop belts of Triassic, Ordovician, and Cambrian rocks in the Frederick Valley region of Maryland's western Piedmont. Detailed stratigraphic analysis and geologic and karst mapping demonstrate that individual stratigraphic units have differing susceptibilities of karst feature creation. Although the Triassic Leesburg Member of the Bull Run Formation and Rocky Springs Station Member of the Cambrian Frederick Formation have many surface depressions within their outcrop belts, the Lime Kiln Member of the Frederick Formation and the Ceresville, Fountain Rock, and Woodsboro members of the Ordovician Grove Formation have the greatest potential for development of catastrophic collapse sinkholes. Although these four members have the highest relative susceptibility, human activity can increase the potential for sinkhole activation in all units. Rerouting of surface drainage patterns, unlined drainage, and storm-water management areas and removal of significant overburden deposits significantly increase sinkhole development, but mainly, these units are inherently more susceptible to begin with. Copyright ?? 2007. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

  15. Groundwater monitoring for cement kiln dust disposal units in karst aquifers

    NASA Astrophysics Data System (ADS)

    Zhou, Wanfang; Beck, Barry F.; Wang, Jie; Pettit, Arthur J.

    2007-04-01

    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.

  16. Evaluating karst geotechnical risk in the urbanized area of Sete Lagoas, Minas Gerais, Brazil

    NASA Astrophysics Data System (ADS)

    Galvão, Paulo; Halihan, Todd; Hirata, Ricardo

    2015-11-01

    An increase in groundwater consumption in the municipality of Sete Lagoas (Minas Gerais, Brazil) has induced subsidence and collapse in the last three decades. The area is associated with natural karst conditions. The primary objective of this research was to evaluate and identify the potential subsidence or collapse risk zones. Aerial photographs, lithologic well profiles, optical well logs, and geologic mapping were utilized to categorize risk factors influencing karst subsidence and collapse, which were then applied to an index system. The study showed that the majority of the urbanized area overlies mantled limestone from the Sete Lagoas Formation covered with unconsolidated sediments, contained within a graben, resulting in barrier boundaries for groundwater flow. This structure, together with natural karst processes, explains the location of solutionally enlarged bedding-plane conduits and high hydraulic conductivity in the limestone. Five risks zones in the municipality were identified (negligible, low, moderate, considerable, and high risks) related to geologic and hydrologic risk factors. The urbanized area is located largely in the high risk zone where the majority of the collapse features are located. Additional intensive groundwater extraction in that area will likely generate additional events.

  17. Influence of karst hydrology on water quality management in southeast South Australia

    NASA Astrophysics Data System (ADS)

    Emmett, A. J.; Telfer, A. L.

    1994-03-01

    Southeast South Australia has large reserves of potable groundwater, generally close to the surface. European settlement has had a major impact on groundwater quality due to the presence of extensive karst in the unconfined aquifer. Historically, industries such as cheese factories were often sited close to karst features (e.g. caves and sinkholes) because they provided a convenient means of waste disposal. Although most have long since closed, they have left a legacy of pollution plumes of varying sizes. In Mount Gambier, the main regional centre, the presence of both exposed and subterranean karst features provided a “perfect system” for the disposal of stormwater. Prior to the provision of a sewerage system within Mount Gambier, all toilet and household wastewaters were disposed to ground. These activities and the subsequent problems that began emerging in the 1960s have led to a concerted effort over the last 20 years to change the philosophy of waste disposal and to generate an understanding and responsibility by those who live in the region and depend on groundwater for the major part of their water supply. Mount Gambier's water supply comes from the Blue Lake. Groundwater inflow from a highly karstic Tertiary limestone aquifer provides 90% of the recharge to the Blue Lake. The lake is a high-value resource in a high-risk environment and in order to minimize this risk, a water-quality management plan for the lake is currently being developed.

  18. Pepino (Solanum muricatum) planting increased diversity and abundance of bacterial communities in karst area

    PubMed Central

    Hu, Jinxiang; Yang, Hui; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-01-01

    Soil nutrients and microbial communities are the two key factors in revegetation of barren environments. Ecological stoichiometry plays an important role in ecosystem function and limitation, but the relationships between above- and belowground stoichiometry and the bacterial communities in a typical karst region are poorly understood. We used pepino (Solanum muricatum) to examine the stoichiometric traits between soil and foliage, and determine diversity and abundance of bacteria in the karst soil. The soil had a relatively high pH, low fertility, and coarse texture. Foliar N:P ratio and the correlations with soil nitrogen and phosphorus suggested nitrogen limitation. The planting of pepino increased soil urease activity and decreased catalase activity. Higher diversity of bacteria was determined in the pepino rhizosphere than bulk soil using a next-generation, Illumina-based sequencing approach. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. On a genus level, all 625 detected genera were found in all rhizosphere and bulk soils, and 63 genera showed significant differences among samples. Higher Shannon and Chao 1 indices in the rhizosphere than bulk soil indicated that planting of pepino increased diversity and abundance of bacterial communities in karst area. PMID:26902649

  19. Assessing the Nonlinearity of Karst Response Function under Variable Boundary Conditions.

    PubMed

    Duran, Léa; Fournier, Matthieu; Massei, Nicolas; Dupont, Jean-Paul

    2016-01-01

    The hydraulic and transfer response of karst aquifers is complex and often highly nonlinear: due to their high transmissivity and connection with the surface, such systems are very sensitive to modifications of their boundary conditions. The aim of this study was to assess the variation of the response depending on both upstream and downstream parameters, and propose a methodology to simulate the response of the karst system depending on those parameters. The impact of the variations of multiple environmental parameters on the response of a karstic system submitted to tidal variations (Normandy, France) was investigated after a campaign of artificial tracer tests acquired in very different hydrologic conditions (rainfall events, low tide, high tide, low/high piezometric level, and low/high waters). Principal components analysis and hierarchical clustering were applied on both environmental variables and karstic system response variables (parameters of the residence time distribution [RTD] curves). Equations between the RTD parameters and the most relevant variables were established using a symbolic regression algorithm. It appeared that the variations of the RTD parameters depend mainly on the cumulated rainfall preceding the injection, the piezometric level of the aquifer, and on the tide parameters. The hydraulic conditions downstream of the aquifer have a strong influence on the hydraulic and transfer response of the aquifer. The response of the aquifer in various and extreme conditions has been simulated using the equations resulting from the symbolic regression algorithm. Such relationships can be useful for management of water resources in karst media, and support decision making.

  20. Pepino (Solanum muricatum) planting increased diversity and abundance of bacterial communities in karst area.

    PubMed

    Hu, Jinxiang; Yang, Hui; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-02-23

    Soil nutrients and microbial communities are the two key factors in revegetation of barren environments. Ecological stoichiometry plays an important role in ecosystem function and limitation, but the relationships between above- and belowground stoichiometry and the bacterial communities in a typical karst region are poorly understood. We used pepino (Solanum muricatum) to examine the stoichiometric traits between soil and foliage, and determine diversity and abundance of bacteria in the karst soil. The soil had a relatively high pH, low fertility, and coarse texture. Foliar N:P ratio and the correlations with soil nitrogen and phosphorus suggested nitrogen limitation. The planting of pepino increased soil urease activity and decreased catalase activity. Higher diversity of bacteria was determined in the pepino rhizosphere than bulk soil using a next-generation, Illumina-based sequencing approach. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. On a genus level, all 625 detected genera were found in all rhizosphere and bulk soils, and 63 genera showed significant differences among samples. Higher Shannon and Chao 1 indices in the rhizosphere than bulk soil indicated that planting of pepino increased diversity and abundance of bacterial communities in karst area.

  1. Classification of karst springs for flash-flood-prone areas in western Turkey

    NASA Astrophysics Data System (ADS)

    Demiroglu, Muhterem

    2016-06-01

    Flash floods are caused by heavy rainfall that has become more frequent. They are more prominent in low-storage karst regions, although karst terrain often acts as a natural flood control particularly when it is bare and dominated by conduits. A study using a hydrogeochemical approach and assessing data from several springs in different carbonate rock in western Turkey has made it possible to classify karst aquifers based on their response to heavy rainfall events. According to this aim, physico-chemical measurements in wet and dry seasons and discharge rates in springs are compared in order to explain aquifer characteristics. Groundwater samples have a pH ranging from 6.3 to 8.9, temperature (T) varying from 7 to 35 °C and electrical conductivity (EC) ranging from 140 to 998 µs cm-1. Groundwater samples with high EC, high T and low dissolved oxygen (DO) represent the deep circulating water, while low EC, low T and high DO are linked to the shallow circulating water. Lower variability between wet and dry seasons reveals that fracture permeability is predominantly controlled by diffuse groundwater flow with low or high storage, and conduit permeability with high storage. However, variability of the physico-chemical characteristics is higher in a conduit permeability with low storage. These types of aquifers with high transfer capability, predominantly controlled by turbulent groundwater flow, affect flash floods.

  2. Effect of karst rocky desertification on soil fungal communities in Southwest China.

    PubMed

    Wang, P C; Mo, B T; Chen, Y; Zeng, Q F; Wang, L B

    2016-07-29

    Karst mountainous ecosystems are associated with karst rocky desertification (KRD), which can greatly impact soil structure and function. Despite the importance of soil microbes as a major factor maintaining ecosystem stability, we know little about the effect on soil fungal communities of KRD in karst regions. We investigated this relationship across a gradient of KRD soils from Guizhou, China by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE). Fungal diversity indices (Shannon-Wiener, richness, and evenness) significantly differed (P < 0.05) based on KRD severity, being lowest in moderately affected areas. Cluster analysis showed that the five sites examined clustered into two main groups according to KRD grade (high and low). Moreover, a homology search using sequences recovered from PCR-DGGE bands showed that the dominant fungi in each community varied remarkably, and included Aspergillus, Aphanoascus, Blastomyces, Fusarium, Glomus, Geomyces, Gibberella, Mortierella, Tetracladium, and Tumularia species, and an unclassified group. In conclusion, these findings demonstrate that KRD has a significant impact on soil fungal communities.

  3. HISTORICAL CONTAMINATION OF GROUNDWATER RESOURCES IN THE NORTH COAST KARST AQUIFERS OF PUERTO RICO.

    PubMed

    Padilla, Ingrid; Irizarry, Celys; Steele, Katherine

    2011-01-01

    The North Coast Karst Aquifer System of Puerto Rico is the island's most productive aquifer. The characteristics that make it highly productive also make it vulnerable to contamination. This research, which addresses the historical contamination of groundwater resources in the northern karst region was conducted through integration of spatial hydrogeologic and contaminant concentration data in the La Plata-Arecibo area. The study used GIS technologies and focused on phthalates and chlorinated volatile organic compounds (CVOCs) and phthalates due to their ubiquitous presence in the environment as well as their presence in listed and potential superfund sites in Puerto Rico and U.S. and potential for exposure and health impacts. Results show an extensive historical contamination of the groundwater resources in the northern karst aquifers. Long-term contamination indicates the aquifers' large capacity for storing and releasing contaminants and reflects a long-term potential for exposure. The degradation of this important water resource has resulted in a subsequent reduction of the extraction capacity and an increase in the cost of use.

  4. Microbial atrazine breakdown in a karst groundwater system and its effect on ecosystem energetics.

    PubMed

    Iker, Brandon C; Kambesis, Pat; Oehrle, Stuart A; Groves, Chris; Barton, Hazel A

    2010-01-01

    In the absence of sunlight energy, microbial community survival in subterranean aquifers depends on integrated mechanisms of energy and nutrient scavenging. Because karst aquifers are particularly sensitive to agricultural land use impacts due to rapid and direct hydrologic connections for pollutants to enter the groundwater, we examined the fate of an exogenous pesticide (atrazine) into such an aquifer and its impact on microbial ecosystem function. Atrazine and its degradation product deethylatrazine (DEA) were detected in a fast-flowing karst aquifer underlying atrazine-impacted agricultural land. By establishing microbial cultures with sediments from a cave conduit within this aquifer, we observed two distinct pathways of microbial atrazine degradation: (i) in cave sediments previously affected by atrazine, apparent surface-derived catabolic genes allowed the microbial communities to rapidly degrade atrazine via hydroxyatrazine, to cyanuric acid, and (ii) in low-impact sediments not previously exposed to this pesticide, atrazine was also degraded by microbial activity at a much slower rate, with DEA as the primary degradation product. In sediments from both locations, atrazine affected nitrogen cycling by altering the abundance of nitrogen dissimulatory species able to use nitrogenous compounds for energy. The sum of these effects was that the presence of atrazine altered the natural microbial processes in these cave sediments, leading to an accumulation of nitrate. Such changes in microbial ecosystem dynamics can alter the ability of DEA to serve as a proxy for atrazine contamination and can negatively affect ecosystem health and water quality in karst aquifers.

  5. Caffeine as an indicator for the quantification of untreated wastewater in karst systems.

    PubMed

    Hillebrand, Olav; Nödler, Karsten; Licha, Tobias; Sauter, Martin; Geyer, Tobias

    2012-02-01

    Contamination from untreated wastewater leakage and related bacterial contamination poses a threat to drinking water quality. However, a quantification of the magnitude of leakage is difficult. The objective of this work is to provide a highly sensitive methodology for the estimation of the mass of untreated wastewater entering karst aquifers with rapid recharge. For this purpose a balance approach is adapted. It is based on the mass flow of caffeine in spring water, the load of caffeine in untreated wastewater and the daily water consumption per person in a spring catchment area. Caffeine is a source-specific indicator for wastewater, consumed and discharged in quantities allowing detection in a karst spring. The methodology was applied to estimate the amount of leaking and infiltrating wastewater to a well investigated karst aquifer on a daily basis. The calculated mean volume of untreated wastewater entering the aquifer was found to be 2.2 ± 0.5 m(3) d(-1) (undiluted wastewater). It corresponds to approximately 0.4% of the total amount of wastewater within the spring catchment.

  6. Effect of karst rocky desertification on soil fungal communities in Southwest China.

    PubMed

    Wang, P C; Mo, B T; Chen, Y; Zeng, Q F; Wang, L B

    2016-01-01

    Karst mountainous ecosystems are associated with karst rocky desertification (KRD), which can greatly impact soil structure and function. Despite the importance of soil microbes as a major factor maintaining ecosystem stability, we know little about the effect on soil fungal communities of KRD in karst regions. We investigated this relationship across a gradient of KRD soils from Guizhou, China by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE). Fungal diversity indices (Shannon-Wiener, richness, and evenness) significantly differed (P < 0.05) based on KRD severity, being lowest in moderately affected areas. Cluster analysis showed that the five sites examined clustered into two main groups according to KRD grade (high and low). Moreover, a homology search using sequences recovered from PCR-DGGE bands showed that the dominant fungi in each community varied remarkably, and included Aspergillus, Aphanoascus, Blastomyces, Fusarium, Glomus, Geomyces, Gibberella, Mortierella, Tetracladium, and Tumularia species, and an unclassified group. In conclusion, these findings demonstrate that KRD has a significant impact on soil fungal communities. PMID:27525893

  7. [Kriging analysis of vegetation index depression in peak cluster karst area].

    PubMed

    Yang, Qi-Yong; Jiang, Zhong-Cheng; Ma, Zu-Lu; Cao, Jian-Hua; Luo, Wei-Qun; Li, Wen-Jun; Duan, Xiao-Fang

    2012-04-01

    In order to master the spatial variability of the normal different vegetation index (NDVI) of the peak cluster karst area, taking into account the problem of the mountain shadow "missing" information of remote sensing images existing in the karst area, NDVI of the non-shaded area were extracted in Guohua Ecological Experimental Area, in Pingguo County, Guangxi applying image processing software, ENVI. The spatial variability of NDVI was analyzed applying geostatistical method, and the NDVI of the mountain shadow areas was predicted and validated. The results indicated that the NDVI of the study area showed strong spatial variability and spatial autocorrelation resulting from the impact of intrinsic factors, and the range was 300 m. The spatial distribution maps of the NDVI interpolated by Kriging interpolation method showed that the mean of NDVI was 0.196, apparently strip and block. The higher NDVI values distributed in the area where the slope was greater than 25 degrees of the peak cluster area, while the lower values distributed in the area such as foot of the peak cluster and depression, where slope was less than 25 degrees. Kriging method validation results show that interpolation has a very high prediction accuracy and could predict the NDVI of the shadow area, which provides a new idea and method for monitoring and evaluation of the karst rocky desertification.

  8. Soil gas screening for chlorinated solvents at three contaminated karst sites in Tennessee

    USGS Publications Warehouse

    Wolfe, W.J.; Williams, S.D.

    2002-01-01

    Soil gas was sampled using active sampling techniques and passive collectors at three sites in Tennessee to evaluate the effectiveness of these techniques for locating chlorinated solvent sources and flowpaths in karst aquifers. Actively collected soil gas samples were analyzed in the field with a portable gas chromatograph, and the passive soil gas collectors were analyzed in the lab with gas chromatography/mass spectrometry. Results of the sampling indicate that the effectiveness of both techniques is highly dependent on the distribution of the contaminants in the subsurface, the geomorphic and hydrogeologic characteristics of the site, and, in one case, on seasonal conditions. Both active and passive techniques identified areas of elevated subsurface chlorinated solvent concentrations at a landfill site where contamination remains concentrated in the regolith. Neither technique detected chlorinated solvents known to be moving in the bedrock at a manufacturing site characterized by thick regolith and an absence of surficial karst features. Passive soil gas sampling had varied success detecting flowpaths for chloroform in the bedrock at a train derailment site characterized by shallow regolith and abundant surficial karst features. At the train derailment site, delineation of the contaminant flowpath through passive soil gas sampling was stronger and more detailed under Winter conditions than summer.

  9. Groundwater vulnerability assessment for the karst aquifer of Tanour and Rasoun spring using EPIK, COP, and travel time methods

    NASA Astrophysics Data System (ADS)

    Hamdan, Ibraheem; Sauter, Martin; Margane, Armin; Ptak, Thomas; Wiegand, Bettina

    2016-04-01

    Key words: Karst, groundwater vulnerability, EPIK, COP, travel time, Jordan. Karst aquifers are especially sensitive to short-lived contaminants because of fast water travel times and a low storage capacity in the conduit system. Tanour and Rasoun karst springs located around 75 km northwest of the city of Amman in Jordan represent the main domestic water supply for the surrounding villages. Both springs suffer from pollution events especially during the winter season, either by microbiological contamination due to wastewater leakage from septic tanks or by wastewater discharge from local olive oil presses. To assess the vulnerability of the karst aquifer of Tanour and Rasoun spring and its sensitivity for pollution, two different intrinsic groundwater vulnerability methods were applied: EPIK and COP. In addition, a travel time vulnerability method was applied to determine the time water travels from different points in the catchment to the streams, as a function of land surface gradients and presumed lateral flow within the epikarst. For the application of the COP and EPIK, a detailed geological survey was carried out to determine karst features and the karst network development within the catchment area. In addition, parameters, such as soil data, long term daily precipitation data, land use and topographical data were collected. For the application of the travel time vulnerability method, flow length, hydraulic conductivity, effective porosity, and slope gradient was used in order to determining the travel time in days. ArcGIS software was used for map preparation. The results of the combined vulnerability methods (COP, EPIK and travel time) show a high percentage of "very high" to "moderate" vulnerable areas within the catchment area of Tanour and Rasoun karst springs. Therefore, protection of the catchment area of Tanour and Rasoun springs from pollution and proper management of land use types is urgently needed to maintain the quality of drinking water in the

  10. Attenuation of arsenic in a karst subterranean stream and correlation with geochemical factors: a case study at Lihu, South China.

    PubMed

    Zhang, Liankai; Yang, Hui; Tang, Jiansheng; Qin, Xiaoqun; Yu, Au Yik

    2014-11-01

    Arsenic (As) pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucidate the reaction mechanisms of arsenic in karst subterranean streams, physical-chemical analysis was conducted by an inductively coupled plasma mass spectrometer and an X-ray fluorescence spectrometer. The results show that inorganic species account for most of the total arsenic, whereas organic arsenic is not detected or occurs in infinitesimal amounts. As(III) accounts for 51.0%±9.9% of the total inorganic arsenic. Arsenic attenuation occurs and the attenuation rates of total As, As(III) and As(V) in the Lihu subterranean stream are 51%, 36% and 59%, respectively. To fully explain the main geochemical factors influencing arsenic attenuation, SPSS 13.0 and CANOCO 4.5 bundled with CanoDraw for Windows were used for simple statistical analysis and redundancy analysis (RDA). Eight main factors, i.e., sediment iron (SFe), sediment aluminum (SAl), sediment calcium (SCa), sediment organic matter (SOM), sediment manganese (SMn), water calcium (WCa(2+)), water magnesium (WMg(2+)), and water bicarbonate ion (WHCO3(-)) were extracted from thirteen indicators. Their impacts on arsenic content rank as: SFe>SCa>WCa(2+)>SAl>WHCO3(-)>SMn>SOM>WMg(2+). Of these factors, SFe, SAl, SCa, SOM, SMn, WMg(2+) and WCa(2+) promote arsenic attenuation, whereas WHCO3(-) inhibits it. Further investigation revealed that the redox potential (Eh) and pH are adverse to arsenic removal. The dramatic distinction between karst and non-karst terrain is that calcium and bicarbonate are the primary factors influencing arsenic migration in karst areas due to the high calcium concentration and alkalinity of karst water.

  11. Improved 2-D resistivity imaging of features in covered karst terrain with arrays of implanted electrodes

    NASA Astrophysics Data System (ADS)

    Kiflu, H. G.; Kruse, S. E.; Harro, D.; Loke, M. H.; Wilkinson, P. B.

    2013-12-01

    Electrical resistivity tomography is commonly used to identify geologic features associated with sinkhole formation. In covered karst terrain, however, it can be difficult to resolve the depth to top of limestone with this method. This is due to the fact that array lengths, and hence depth of resolution, are often limited by residential or commercial lot dimensions in urban environments. Furthermore, the sediments mantling the limestone are often clay-rich and highly conductive. The resistivity method has limited sensitivity to resistive zones beneath conductive zones. This sensitivity can be improved significantly with electrodes implanted at depth in the cover sediments near the top of limestone. An array of deep electrodes is installed with direct push technology in the karst cover. When combined with a surface array in which each surface electrode is underlain by a deep electrode, the array geometry is similar to a borehole array turned on its side. This method, called the Multi-Electrode Resistivity Implant Technique (MERIT), offers the promise of significantly improved resolution of epikarst and cover collapse development zones in the overlying sediment, the limestone or at the sediment-bedrock interface in heterogeneous karst environments. With a non-traditional array design, the question of optimal array geometries arises. Optimizing array geometries is complicated by the fact that many plausible 4-electrode readings will produce negative apparent resistivity values, even in homogeneous terrain. Negative apparent resistivities cannot be used in inversions based on the logarithm of the apparent resistivity. New algorithms for seeking optimal array geometries have been developed by modifying the 'Compare R' method of Wilkinson and Loke. The optimized arrays show significantly improved resolution over basic arrays adapted from traditional 2D surface geometries. Several MERIT case study surveys have been conducted in covered karst in west-central Florida, with

  12. Factors affecting ground-water exchange and catchment size for Florida lakes in mantled karst terrain

    USGS Publications Warehouse

    Lee, Terrie Mackin

    2002-01-01

    In the mantled karst terrain of Florida, the size of the catchment delivering ground-water inflow to lakes is often considerably smaller than the topographically defined drainage basin. The size is determined by a balance of factors that act individually to enhance or diminish the hydraulic connection between the lake and the adjacent surficial aquifer, as well as the hydraulic connection between the surficial aquifer and the deeper limestone aquifer. Factors affecting ground-water exchange and the size of the ground-water catchment for lakes in mantled karst terrain were examined by: (1) reviewing the physical and hydrogeological characteristics of 14 Florida lake basins with available ground-water inflow estimates, and (2) simulating ground-water flow in hypothetical lake basins. Variably-saturated flow modeling was used to simulate a range of physical and hydrogeologic factors observed at the 14 lake basins. These factors included: recharge rate to the surficial aquifer, thickness of the unsaturated zone, size of the topographically defined basin, depth of the lake, thickness of the surficial aquifer, hydraulic conductivity of the geologic units, the location and size of karst subsidence features beneath and onshore of the lake, and the head in the Upper Floridan aquifer. Catchment size and the magnitude of ground-water inflow increased with increases in recharge rate to the surficial aquifer, the size of the topographically defined basin, hydraulic conductivity in the surficial aquifer, the degree of confinement of the deeper Upper Floridan aquifer, and the head in the Upper Floridan aquifer. The catchment size and magnitude of ground-water inflow increased with decreases in the number and size of karst subsidence features in the basin, and the thickness of the unsaturated zone near the lake. Model results, although qualitative, provided insights into: (1) the types of lake basins in mantled karst terrain that have the potential to generate small and large

  13. Linking climate change and karst hydrology to evaluate species vulnerability: The Edwards and Madison aquifers (Invited)

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Long, A. J.; Stamm, J. F.; Poteet, M.; Symstad, A.

    2013-12-01

    Karst aquifers present an extreme case of flow along structurally variable pathways, making them highly dynamic systems and therefore likely to respond rapidly to climate change. In turn, many biological communities and ecosystems associated with karst are sensitive to hydrologic changes. We explored how three sites in the Edwards aquifer (Texas) and two sites in the Madison aquifer (South Dakota) might respond to projected climate change from 2011 to 2050. Ecosystems associated with these karst aquifers support federally listed endangered and threatened species and state-listed species of concern, including amphibians, birds, insects, and plants. The vulnerability of selected species associated with projected climate change was assessed. The Advanced Research Weather and Research Forecasting (WRF) model was used to simulate projected climate at a 36-km grid spacing for three weather stations near the study sites, using boundary and initial conditions from the global climate model Community Climate System Model (CCSM3) and an A2 emissions scenario. Daily temperature and precipitation projections from the WRF model were used as input for the hydrologic Rainfall-Response Aquifer and Watershed Flow (RRAWFLOW) model and the Climate Change Vulnerability Index (CCVI) model. RRAWFLOW is a lumped-parameter model that simulates hydrologic response at a single site, combining the responses of quick and slow flow that commonly characterize karst aquifers. CCVI uses historical and projected climate and hydrologic metrics to determine the vulnerability of selected species on the basis of species exposure to climate change, sensitivity to factors associated with climate change, and capacity to adapt to climate change. An upward trend in temperature was projected for 2011-2050 at all three weather stations; there was a trend (downward) in annual precipitation only for the weather station in Texas. A downward trend in mean annual spring flow or groundwater level was projected for

  14. Can one identify karst conduit networks geometry and properties from hydraulic and tracer test data?

    NASA Astrophysics Data System (ADS)

    Borghi, Andrea; Renard, Philippe; Cornaton, Fabien

    2016-04-01

    Karst aquifers are characterized by extreme heterogeneity due to the presence of karst conduits embedded in a fractured matrix having a much lower hydraulic conductivity. The resulting contrast in the physical properties of the system implies that the system reacts very rapidly to some changes in the boundary conditions and that numerical models are extremely sensitive to small modifications in properties or positions of the conduits. Furthermore, one major issue in all those models is that the location and size of the conduits is generally unknown. For all those reasons, estimating karst network geometry and their properties by solving an inverse problem is a particularly difficult problem. In this paper, two numerical experiments are described. In the first one, 18,000 flow and transport simulations have been computed and used in a systematic manner to assess statistically if one can retrieve the parameters of a model (geometry and radius of the conduits, hydraulic conductivity of the conduits) from head and tracer data. When two tracer test data sets are available, the solution of the inverse problems indicate with high certainty that there are indeed two conduits and not more. The radius of the conduits are usually well identified but not the properties of the matrix. If more conduits are present in the system, but only two tracer test data sets are available, the inverse problem is still able to identify the true solution as the most probable but it also indicates that the data are insufficient to conclude with high certainty. In the second experiment, a more complex model (including non linear flow equations in conduits) is considered. In this example, gradient-based optimization techniques are proved to be efficient for estimating the radius of the conduits and the hydraulic conductivity of the matrix in a promising and efficient manner. These results suggest that, despite the numerical difficulties, inverse methods should be used to constrain numerical

  15. Nitrogen budget of a typical subterranean river in peak cluster karst area

    NASA Astrophysics Data System (ADS)

    Guo, Fang; Jiang, Guanghui

    2009-10-01

    Karst groundwater is one of the important water resources for people in the world. There is an estimate that by 2028 karst groundwater will supply more than 80% of people in the world. However, several areas in the world are characterized by high nitrate concentrations in karst aquifers. In China, karst groundwater is also threatened by extensive use of fertilizer and pesticides, industry waste, septic systems and poultry, hog or cattle manure. In order to understand the water quality of a subterranean river in south China, especially the dynamic variation of nitrate, nitrogen input and output were determined via auto-monitored apparatus, manual observation and samples from 2004 to 2008 in Guancun subterranean river drainage area. Land use and anthropogenic activities were also investigated frequently. The results showed the range of nitrate variation was 2.56-15.40 mg l-1, with an average value of 6.60 mg l-1. Spatial variation of nitrate concentrations showed nitrate rose where there were villages and agriculture distribution. Long series of nitrate and discharge monitoring revealed there was a nitrate peak in spring just before the beginning of rainy season. Three rainfall events were selected for analysis of relations among hydrological process, water chemistry, and nitrate of the spring. The flood processes of the spring were divided into three or four phases according to change of water level and water chemistry. They were dominated by initial condition of aquifer, piston flow in soil and vadose, piston flow in conduit, diffuse recharge, and bypass recharge. The original condition of aquifer and rainfall pulse controlled recharge flow and changes of nitrate and hydro-chemical graphs of the spring. The quantity of nitrogen input in a year was 66.61 t, and the output was 21.24 t. Nitrogen leaching loss in base flow accounted for 76.11% in a year. Some measures should be taken to protect karst water in the very near future, so that health risks to the local

  16. Determination of the sources of nitrate contamination in karst springs using isotopic and chemical indicators

    USGS Publications Warehouse

    Panno, S.V.; Hackley, Keith C.; Hwang, H.-H.; Kelly, W.R.

    2001-01-01

    The sources of nitrate (NO-3) in groundwater of the shallow karst aquifer in southwestern Illinois' sinkhole plain were investigated using chemical and isotopic techniques. The groundwater in this aquifer is an important source of potable water for about half of the residents of the sinkhole plain area. Previous work has shown that groundwater from approximately 18% of the wells in the sinkhole plain has NO-3 concentrations in excess of the USEPA's drinking water standard of 10 mg N/1. Relative to background levels, the NO-3 concentrations in water from 52% of the wells, and probably all of the springs in the study area, are anomalously high, suggesting that sources other than naturally occurring soil organic matter have contributed additional NO-3 to groundwater in the shallow karst aquifer. This information, and the dominance of agriculture in the study area, suggest that agrichemical contributions may be significant. To test this hypothesis, water samples from 10 relatively large karst springs were collected during four different seasons and analyzed for inorganic constituents, dissolved organic carbon, atrazine, and ??15N and ??18O of the NO-3 ions. The isotopic data were most definitive and suggested that the sources of NO-3 in spring water are dominated by N-fertilizer with some possible influence of atmospheric NO-3 and, to a much lesser extent, human and/or animal waste. Differences in the isotopic composition of NO-3 and some of the chemical characteristics were observed during the four consecutive seasons in which spring water samples were collected. Isotopic values for ??15N and ??18O of the NO-3 ranged from 3.2??? to 19.1??? and from 7.2??? to 18.7???, respectively. The trend of ??15N and ??18O data for NO-3 also indicated that a significant degree of denitrification is occurring in the shallow karst hydrologic system (within the soil zone, the epikarst and the shallow karst aquifer) prior to discharging to springs. ?? 2001 Elsevier Science B.V. All

  17. Geo-Hydro Statistical Characterization of Preferential Flow and Transport Processes in Karst Groundwater Systems

    NASA Astrophysics Data System (ADS)

    Anaya, A. A.; Padilla, I. Y.; Macchiavelli, R. E.

    2011-12-01

    Karst groundwater systems are highly productive and provide an important fresh water resource for human development and ecological integrity. Their high productivity is often associated with conduit flow and high matrix permeability. The same characteristics that make these aquifers productive also make them highly vulnerable to contamination and a likely for contaminant exposure. Of particular interest are chlorinated organic contaminants and phthalates derived from industrial solvents and plastic by-products. These chemicals have been identified as potential precursors of pre-term birth, a leading cause of neonatal complications with a significant health and societal cost. The general objectives of this work are to: (1) develop fundamental knowledge and determine the processes controlling the release, mobility, persistence, and possible pathways of contaminants in karst groundwater systems, and (2) characterize transport processes in conduit and diffusion-dominated flow under base flow and storm flow conditions. The work presented herein focuses on the development of geo-hydro statistical tools to characterize flow and transport processes under different flow regimes. Multidimensional, laboratory-scale Geo-Hydrobed models were developed and tested for this purpose. The models consist of stainless-steel tanks containing karstified limestone blocks collected from the karst aquifer formation of northern Puerto Rico. The models a network of sampling wells to monitor flow, pressure, and solute concentrations temporally and spatially. Experimental work entailed making a series of point injections in wells while monitoring the hydraulic response in other wells. Statistical mixed models were applied to spatial probabilities of hydraulic response and weighted injected volume data, and were used to determinate the best spatial correlation structure to represent paths of preferential flow in the limestone units under different groundwater flow regimes. Preliminary testing

  18. Quantification of frequency-components contributions to the discharge of a karst spring

    NASA Astrophysics Data System (ADS)

    Taver, V.; Johannet, A.; Vinches, M.; Borrell, V.; Pistre, S.; Bertin, D.

    2013-12-01

    Karst aquifers represent important underground resources for water supplies, providing it to 25% of the population. Nevertheless such systems are currently underexploited because of their heterogeneity and complexity, which make work fields and physical measurements expensive, and frequently not representative of the whole aquifer. The systemic paradigm appears thus at a complementary approach to study and model karst aquifers in the framework of non-linear system analysis. Its input and output signals, namely rainfalls and discharge contain information about the function performed by the physical process. Therefore, improvement of knowledge about the karst system can be provided using time series analysis, for example Fourier analysis or orthogonal decomposition [1]. Another level of analysis consists in building non-linear models to identify rainfall/discharge relation, component by component [2]. In this context, this communication proposes to use neural networks to first model the rainfall-runoff relation using frequency components, and second to analyze the models, using the KnoX method [3], in order to quantify the importance of each component. Two different neural models were designed: (i) the recurrent model which implements a non-linear recurrent model fed by rainfalls, ETP and previous estimated discharge, (ii) the feed-forward model which implements a non-linear static model fed by rainfalls, ETP and previous observed discharges. The first model is known to better represent the rainfall-runoff relation; the second one to better predict the discharge based on previous discharge observations. KnoX method is based on a variable selection method, which simply considers values of parameters after the training without taking into account the non-linear behavior of the model during functioning. An amelioration of the KnoX method, is thus proposed in order to overcome this inadequacy. The proposed method, leads thus to both a hierarchization and a quantification

  19. Transit time distributions to assess present and future contamination risk of karst aquifers over Europe and the Mediterranean

    NASA Astrophysics Data System (ADS)

    Hartmann, Andreas; Gleeson, Tom; Wada, Yoshihide; Wagener, Thorsten

    2016-04-01

    Karst develops through the dissolution of carbonate rock. Karst groundwater in Europe is a major source of fresh water contributing up to half of the total drinking water supply in some countries. Climate model projections suggest that in the next 100 years, karst regions will experience a strong increase in temperature and a serious decrease of precipitation - especially in the Mediterranean region. Previous work showed that the karstic preferential recharge processes result in enhanced recharge rates and future climate sensitivity. But as there is fast water flow form the surface to the aquifer, there is also an enhanced risk of groundwater contamination. In this study we will assess the contamination risk of karst aquifers over Europe and the Mediterranean using simulated transit time distributions. Using a new type of semi-distributed model that considers the spatial heterogeneity of the karst system by distribution functions we simulated a range of spatially variable pathways of karstic groundwater recharge. The model is driven by the bias-corrected 5 GCMs of the ISI-MIP project (RCP8.5). Transit time distributions are calculated by virtual tracer experiments. These are repeated several times in the present (1991-2010) and the future (2080-2099). We can show that regions with larger fractions of preferential recharge show higher risks of contamination and that spatial patterns of contamination risk change towards the future.

  20. Using streamflow and hydrochemical tracers to conceptualise hydrological function of underground channel system in a karst catchment of southwest China

    NASA Astrophysics Data System (ADS)

    Zhang, Zhicai; Chen, Xi; Wang, Jinli

    2016-04-01

    Karst hydrodynamic behaviour is complex because of special karst geology and geomorphology. The permeable multi-media consisting of soil, epikarst fractures and conduits has a key influence on karst hydrological processes. Spatial heterogeneity is high due to special landforms of vertical shafts, caves and sinkholes, which leads to a high dynamic variability of hydrological processes in space and time, and frequent exchange of surface water and groundwater. Underground water in different reach were sampled over the 1996-2001 in a karst catchment of Houzhai, with 81km2, located in Guizhou province of southwest China. Samples were analysed for water temperature, pH, conductivity and four solute concentrations. The monitoring sought to assess the combined utility of flow discharge and natural geochemical tracers in upscaling flow structure understanding in karst area. Based on previous researches and field investigation, the catchment characteristics were explored with the use of a GIS. Both flow discharge and solute concentrations exhibited clear seasonal patterns at every groundwater sampling sites. The variations of flow and chemistry are more dramatic in upstream site with less soil cover and more sinkholes development, which affect the hydrological pathways significantly. There was clear evidence that the differences in geology and soil were the main controls on hydrology and flow chemistry, which was spatially variable in different sites of underground channel. Conceptual flow structures in main hydrological response units for different area in the catchment were developed according to the variation of discharge and flow chemistry.

  1. [Nitrate storage and transport within a typical karst aquifer system in the paralleled ridge-valley of east Sichuan].

    PubMed

    Yang, Ping-Heng; Yuan, Dao-Xian; Ren, You-Rong; Xie, Shi-You; He, Qiu-Fang; Hu, Xiao-Feng

    2012-09-01

    In order to investigate the nitrate storage and transport in the karst aquifer system, the hydrochemical dynamics of Qingmuguan underground river system was monitored online by achieving high-resolution data during storm events and monthly data in normal weather. The principal component analysis was employed to analyze the karst water geochemistry. Results showed that nitrate in Jiangjia spring did not share the same source with soluble iron, manganese and aluminum, and exhibited different geochemical behaviors. Nitrate was derived from land surface and infiltrated together with soil water, which was mainly stored in fissure, pore and solution crack of karst unsaturated zone, whereas soluble iron, manganese and aluminum were derived from soil erosion and directly recharged the underground river through sinkholes and shafts. Nitrate transport in the karst aquifer system could be ideally divided into three phases, including input storage, fast output and re-inputting storage. Under similar external conditions, the karstification intensity of vadose zone was the key factor to determine the dynamics of nitrate concentrations in the groundwater during storm events. Nitrate stored in the karst vadose zone was easily released, which would impair the aquatic ecosystem and pose seriously threats to the local health. Thus, to strengthen the management of ecological system, changing the land-use patterns and scientifically applying fertilizer could effectively make a contribution to controlling mass nutrient input from the surface.

  2. [Characteristics of foliar delta13C values of common shrub species in various microhabitats with different karst rocky desertification degrees].

    PubMed

    Du, Xue-Lian; Wang, Shi-Jie; Rong, Li

    2011-12-01

    By measuring the foliar delta13C values of 5 common shrub species (Rhamnus davurica, Pyracantha fortuneana, Rubus biflorus, Zanthoxylum planispinum, and Viburnum utile) growing in various microhabitats in Wangjiazhai catchment, a typical karst desertification area in Guizhou Province, this paper studied the spatial heterogeneity of plant water use at niche scale and the response of the heterogeneity to different karst rocky desertification degrees. The foliar delta13C values of the shrub species in the microhabitats followed the order of stony surface > stony gully > stony crevice > soil surface, and those of the majority of the species were more negative in the microhabitat soil surface than in the others. The foliar delta13C values decreased in the sequence of V. utile > R. biflorus > Z. planispinum > P. fortuneana > R. davurica, and the mean foliar delta13C value of the shrubs and that of typical species in various microhabitats all increased with increasing karst rocky desertification degree, differed significantly among different microhabitats. It was suggested that with the increasing degree of karst rocky desertification, the structure and functions of karst habitats were impaired, microhabitats differentiated gradually, and drought degree increased.

  3. Determination of pollution and recovery time of karst springs, an example from a carbonate aquifer in Israel.

    PubMed

    Magal, Einat; Arbel, Yuval; Caspi, Sarit; Glazman, Hilel; Greenbaum, Noam; Yechieli, Yoseph

    2013-02-01

    This work combines the monitoring of two incidents of spring water pollution in the Western Galilee region of Israel, together with artificial tracer tests that provided valuable information regarding karst system connections and direct estimation of groundwater velocities. Almost simultaneous contamination of seven springs endangered the water supply for the region. The variations over time in contaminant concentration in the different springs were not similar, indicating more than one contamination source. Tracer tests revealed two different pollution sources that contributed to two different conduit pathways in the karst system. Breakthrough data for the tracers were modeled by a two-region non-equilibrium transport model, which provided the transport parameters of the karst conduit. Groundwater velocities in the conduits were found to be in a range of 2-3 km/day. The rapid response of the system was also demonstrated by the short recovery time of the springs, where, after the elimination of the pollution source, most water quality parameters reverted to their background concentrations in less than 3 months. The coexistence of highly polluted springs and uncontaminated groundwater in boreholes penetrating into the same aquifer demonstrates the complexity of groundwater flow in karst systems. In such systems, the fast groundwater flow in localized karst conduits seems to coexist with a slower flow within other portions of the aquifer.

  4. U.S. Geological Survey Karst Interest Group Proceedings, Carlsbad, New Mexico, April 29-May 2, 2014

    USGS Publications Warehouse

    Kuniansky, Eve L.; Spangler, Lawrence E.; Kuniansky, Eve L.; Spangler, Lawrence E.

    2014-01-01

    Introduction and Acknowledgments Karst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex, and involve biological, chemical, and physical changes. These factors, combined with the diverse climatic regimes under which karst development in these rocks has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains. The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs has resulted in the most exceptional karst areas of the United States being designated as national or state parks; commercial caverns and known privately owned caves number in the tens of thousands. Both public and private properties provide access for scientists to study the flow of groundwater in situ. Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these karst hydrogeologic systems. As a result, numerous federal

  5. Review: Groundwater flow and transport modeling of karst aquifers, with particular reference to the North Coast Limestone aquifer system of Puerto Rico.

    PubMed

    Ghasemizadeh, Reza; Hellweger, Ferdinand; Butscher, Christoph; Padilla, Ingrid; Vesper, Dorothy; Field, Malcolm; Alshawabkeh, Akram

    2012-12-01

    Karst systems have a high degree of heterogeneity and anisotropy, which makes them behave very differently from other aquifers. Slow seepage through the rock matrix and fast flow through conduits and fractures result in a high variation in spring response to precipitation events. Contaminant storage occurs in the rock matrix and epikarst, but contaminant transport occurs mostly along preferential pathways that are typically inaccessible locations, which makes modeling of karst systems challenging. Computer models for understanding and predicting hydraulics and contaminant transport in aquifers make assumptions about the distribution and hydraulic properties of geologic features that may not always apply to karst aquifers. This paper reviews the basic concepts, mathematical descriptions, and modeling approaches for karst systems. The North Coast Limestone aquifer system of Puerto Rico (USA) is introduced as a case study to illustrate and discuss the application of groundwater models in karst aquifer systems to evaluate aquifer contamination. PMID:23645996

  6. Review: Groundwater flow and transport modeling of karst aquifers, with particular reference to the North Coast Limestone aquifer system of Puerto Rico

    PubMed Central

    Ghasemizadeh, Reza; Hellweger, Ferdinand; Butscher, Christoph; Padilla, Ingrid; Vesper, Dorothy; Field, Malcolm; Alshawabkeh, Akram

    2013-01-01

    Karst systems have a high degree of heterogeneity and anisotropy, which makes them behave very differently from other aquifers. Slow seepage through the rock matrix and fast flow through conduits and fractures result in a high variation in spring response to precipitation events. Contaminant storage occurs in the rock matrix and epikarst, but contaminant transport occurs mostly along preferential pathways that are typically inaccessible locations, which makes modeling of karst systems challenging. Computer models for understanding and predicting hydraulics and contaminant transport in aquifers make assumptions about the distribution and hydraulic properties of geologic features that may not always apply to karst aquifers. This paper reviews the basic concepts, mathematical descriptions, and modeling approaches for karst systems. The North Coast Limestone aquifer system of Puerto Rico (USA) is introduced as a case study to illustrate and discuss the application of groundwater models in karst aquifer systems to evaluate aquifer contamination. PMID:23645996

  7. Review: Groundwater flow and transport modeling of karst aquifers, with particular reference to the North Coast Limestone aquifer system of Puerto Rico.

    PubMed

    Ghasemizadeh, Reza; Hellweger, Ferdinand; Butscher, Christoph; Padilla, Ingrid; Vesper, Dorothy; Field, Malcolm; Alshawabkeh, Akram

    2012-12-01

    Karst systems have a high degree of heterogeneity and anisotropy, which makes them behave very differently from other aquifers. Slow seepage through the rock matrix and fast flow through conduits and fractures result in a high variation in spring response to precipitation events. Contaminant storage occurs in the rock matrix and epikarst, but contaminant transport occurs mostly along preferential pathways that are typically inaccessible locations, which makes modeling of karst systems challenging. Computer models for understanding and predicting hydraulics and contaminant transport in aquifers make assumptions about the distribution and hydraulic properties of geologic features that may not always apply to karst aquifers. This paper reviews the basic concepts, mathematical descriptions, and modeling approaches for karst systems. The North Coast Limestone aquifer system of Puerto Rico (USA) is introduced as a case study to illustrate and discuss the application of groundwater models in karst aquifer systems to evaluate aquifer contamination.

  8. Dynamic Vulnerability of Karst Systems: a Concept to understand qualitative and quantitative Aspects of Karst springs due to Changes in Groundwater Recharge

    NASA Astrophysics Data System (ADS)

    Huggenberger, P.; Butscher, C.; Epting, J.; Auckenthaler, A.

    2015-12-01

    Karst groundwater resources represent valuable water resources, which may be affected by different types of pollution and changes of groundwater recharge by climate change. In many parts of Europe, it has been predicted that record-breaking heat waves, such as the one experienced in 2003 and 2015, will become more frequent. At the same time, even as summers become drier, the incidence of severe precipitation events could increase. What is the influence such changes to the quantitative and qualitative aspects of Karst groundwater systems? A factor to be considered in conjunction with groundwater quality is the vulnerability of the resource, which is defined as the sensitivity of a groundwater system to pollution. Intrinsic vulnerability refers to the sensitivity to pollution when considering only natural, geogenic conditions without the effects of human activities such as contaminant release. Intrinsic vulnerability depends on the recharge conditions, which are dependent on the surface and subsurface structure and on precipitation and evaporation patterns. The latter are highly time dependent. Therefore, our groundwater vulnerability concept also includes dynamic aspects of the system, the variations of spatial and temporal components. We present results of combined monitoring and modelling experiments of several types of Karst systems in the Tabular and the Folded Jura of NW Switzerland. The recharge, conduit flow, diffuse flow(RCD) rainfall-discharge model "RCD-seasonal" was used to simulate the discharge and substance concentration of several spring. This lumped parameter model include: the recharge system (soil and epikarst system), the conduit flow system, and the diffuse flow system. The numerically derived Dynamic Vulnerability Index (DVI) can indicate qualitative changes of spring water with sufficient accuracy to be used for drinking water management. In addition, the results obtained from the test sites indicate a decrease in short-lived contaminants in

  9. An evaluation method of the sustainability of water resource in karst region: a case study of Zunyi, China

    NASA Astrophysics Data System (ADS)

    Li, Bo; Wang, Ganlu; Ding, Hanghang; Chen, Yulong

    2015-11-01

    Water resource is of great significance to the survival and development of human. However, the water resource system in karst regions is sensitive to external interference owing to the special geological processes which cause soil impoverishment, severe rocky desertification and large topographic height difference. Therefore, evaluating the sustainability of the water resource in karst regions is beneficial to reasonably use and protect water resource. This paper puts forward to evaluate the water resource from four aspects, including water resources system, water requirement system, ecosystem and social economic system. Moreover, on this basis, 18 evaluation indexes were selected to construct the sustainability evaluation index system and method. This method was used to evaluate the sustainability of the water resource in the typical karst region—Zunyi, Guizhou province, China, and was verified according to the actual situation in the research area. All these provide reference for the evaluation of the sustainability of the water resource in similar regions.

  10. Hydrogeological approach to investigation in karst for possible modification of groundwater regime and increase of recoverable reserves

    NASA Astrophysics Data System (ADS)

    Komatina, Miomir

    1990-09-01

    An artificial contribution to groundwater reserves in the areas of interest for water supply is a principal methodological target in modern hydrogeology. Investigations directed to this goal are of increasing significance all over the world to meet the growing demand for good water, which groundwater generally can be. Progress has been made in the sphere of practical development in permeable rocks of intergranular porosity, which cannot be said of discontinuous karst media, although it seems to offer greater opportunities. The ingrained notion and fear, even among specialists, of the inherent risk and uncertainty were invariably present wherever a resource was discovered in karst of a geosynclinal area; consequently progress has been limited. The reasons, however, for such a cautious approach are diminishing, because much knowledge has been gained about these aquiferous rocks, especially through investigations in the regions of surface storage reservoirs. Better knowledge of karst features and the results achieved in construction and consolidation of surface reservoirs have indicated that large amounts of groundwater can be recovered. The conventional water investigation and recovery methods have made available only small safe yields equal to the lowest natural discharge on the order of 100 I/sec). A reasonable use of a karst water resource and its better management cannot be considered without artificial control of the groundwater regime, i.e., without adjusting the regime to human demands. Groundwater flow balance in karst is becoming one of the principal problems, and future activities should be directed to the search for a bolder solution. A multidisciplinary team of geologists, geomorphologists, hydrogeologists, hydrologists, hydraulic engineers, etc., is required. In this paper a variety of solutions for water resource utilization in naked geosynclinal karst is suggested and far greater activity in this field is encouraged.

  11. Improving Geologic and Engineering Models of Midcontinent Fracture and Karst-Modified Reservoirs Using New 3-D Seismic Attributes

    SciTech Connect

    Susan Nissen; Saibal Bhattacharya; W. Lynn Watney; John Doveton

    2009-03-31

    Our project goal was to develop innovative seismic-based workflows for the incremental recovery of oil from karst-modified reservoirs within the onshore continental United States. Specific project objectives were: (1) to calibrate new multi-trace seismic attributes (volumetric curvature, in particular) for improved imaging of karst-modified reservoirs, (2) to develop attribute-based, cost-effective workflows to better characterize karst-modified carbonate reservoirs and fracture systems, and (3) to improve accuracy and predictiveness of resulting geomodels and reservoir simulations. In order to develop our workflows and validate our techniques, we conducted integrated studies of five karst-modified reservoirs in west Texas, Colorado, and Kansas. Our studies show that 3-D seismic volumetric curvature attributes have the ability to re-veal previously unknown features or provide enhanced visibility of karst and fracture features compared with other seismic analysis methods. Using these attributes, we recognize collapse features, solution-enlarged fractures, and geomorphologies that appear to be related to mature, cockpit landscapes. In four of our reservoir studies, volumetric curvature attributes appear to delineate reservoir compartment boundaries that impact production. The presence of these compartment boundaries was corroborated by reservoir simulations in two of the study areas. Based on our study results, we conclude that volumetric curvature attributes are valuable tools for mapping compartment boundaries in fracture- and karst-modified reservoirs, and we propose a best practices workflow for incorporating these attributes into reservoir characterization. When properly calibrated with geological and production data, these attributes can be used to predict the locations and sizes of undrained reservoir compartments. Technology transfer of our project work has been accomplished through presentations at professional society meetings, peer-reviewed publications

  12. Spatial analysis for susceptibility of second-time karst sinkholes: A case study of Jili Village in Guangxi, China

    NASA Astrophysics Data System (ADS)

    Zhou, Guoqing; Yan, Hongbo; Chen, Kunhua; Zhang, Rongting

    2016-04-01

    After a big karst sinkhole happened in Jili Village of Guangxi, China, the local government was eager to quantitatively analyze and map susceptible areas of the potential second-time karst sinkholes in order to make timely decisions whether the residents living in the first-time sinkhole areas should move. For this reason, karst sinkholes susceptibility geospatial analysis is investigated using multivariate spatial data, logistic regression model (LRM) and Geographical Information System (GIS). Ten major karst sinkholes related factors, including (1) formation lithology, (2) soil structure, (3) profile curvature, (4) groundwater depth, (5) fluctuation of groundwater level, (6) percolation rate of soil, (7) degree of karst development, (8) distance from fault, (9) distance from the traffic route, and (10) overburden thickness were selected, and then each of factors was classified and quantitated with the three or four levels. The LRM was applied to evaluate which factor makes significant contributions to sinkhole. The results demonstrated that formation lithology, soil structure, profile curvature, groundwater depth, ground water level, percolation rate of soil, and degree of karst development, the distance from fault, and overburden thickness are positive, while one factor, the distance from traffic routes is negative, which is deleted from LRM model. The susceptibility of the potential sinkholes in the study area is estimated and mapped using the solved impact factors. The susceptible degrees of the study area are classified into five levels, very high, high, moderate, low, and ignore susceptibility. It has been found that that both very high and high susceptibility areas are along Datou Hill and the foothills of the study area. This finding is verified by field observations. With the investigations conducted in this paper, it can be concluded that the susceptibility maps produced in this paper are reliable and accurate, and useful as a reference for local

  13. Single event time series analysis in a binary karst catchment evaluated using a groundwater model (Lurbach system, Austria).

    PubMed

    Mayaud, C; Wagner, T; Benischke, R; Birk, S

    2014-04-16

    The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and the

  14. Single event time series analysis in a binary karst catchment evaluated using a groundwater model (Lurbach system, Austria)

    PubMed Central

    Mayaud, C.; Wagner, T.; Benischke, R.; Birk, S.

    2014-01-01

    Summary The Lurbach karst system (Styria, Austria) is drained by two major springs and replenished by both autogenic recharge from the karst massif itself and a sinking stream that originates in low permeable schists (allogenic recharge). Detailed data from two events recorded during a tracer experiment in 2008 demonstrate that an overflow from one of the sub-catchments to the other is activated if the discharge of the main spring exceeds a certain threshold. Time series analysis (autocorrelation and cross-correlation) was applied to examine to what extent the various available methods support the identification of the transient inter-catchment flow observed in this binary karst system. As inter-catchment flow is found to be intermittent, the evaluation was focused on single events. In order to support the interpretation of the results from the time series analysis a simplified groundwater flow model was built using MODFLOW. The groundwater model is based on the current conceptual understanding of the karst system and represents a synthetic karst aquifer for which the same methods were applied. Using the wetting capability package of MODFLOW, the model simulated an overflow similar to what has been observed during the tracer experiment. Various intensities of allogenic recharge were employed to generate synthetic discharge data for the time series analysis. In addition, geometric and hydraulic properties of the karst system were varied in several model scenarios. This approach helps to identify effects of allogenic recharge and aquifer properties in the results from the time series analysis. Comparing the results from the time series analysis of the observed data with those of the synthetic data a good agreement was found. For instance, the cross-correlograms show similar patterns with respect to time lags and maximum cross-correlation coefficients if appropriate hydraulic parameters are assigned to the groundwater model. The comparable behaviors of the real and

  15. Lanthanide-labeled clay: A new method for tracing sediment transport in Karst

    USGS Publications Warehouse

    Mahler, B.J.; Bennett, P.C.; Zimmerman, M.

    1998-01-01

    Mobile sediment is a fundamental yet poorly characterized aspect of mass transport through karst aquifers. Here the development and field testing of an extremely sensitive particle tracer that may be used to characterize sediment transport in karst aquifers is described. The tracer consists of micron-size montmorillonite particles homoionized to the lanthanide form; after injection and retrieval from a ground water system, the lanthanide ions are chemically stripped from the clay and quantified by high performance liquid chromatography. The tracer meets the following desired criteria: low detection limit; a number of differentiable signatures; inexpensive production and quantification using standard methods; no environmental risks; and hydrodynamic properties similar to the in situ sediment it is designed to trace. The tracer was tested in laboratory batch experiments and field tested in both surface water and ground water systems. In surface water, arrival times of the tracer were similar to those of a conservative water tracer, although a significant amount of material was lost due to settling. Two tracer tests were undertaken in a karst aquifer under different flow conditions. Under normal flow conditions, the time of arrival and peak concentration of the tracer were similar to or preceded that of a conservative water tracer. Under low flow conditions, the particle tracer was not detected, suggesting that in low flow the sediment settles out of suspension and goes into storage.Mobile sediment is a fundamental yet poorly characterized aspect of mass transport through karst aquifers. Here the development and field testing of an extremely sensitive particle tracer that may be used to characterize sediment transport in karst aquifers is described. The tracer consists of micron-size montmorillonite particles homoionized to the lanthanide form; after injection and retrieval from a ground water system, the lanthanide ions are chemically stripped from the clay and

  16. Impact of the hurricanes Gustav and Ike in the karst areas of the Vi

    NASA Astrophysics Data System (ADS)

    Farfàn Gonzalez, H.; Corvea Porras, J. L.; Martinez Maquiera, Y.; Diaz Guanche, C.; Aldana Vilas, C.; de Bustamante, I.; Parise, M.

    2009-04-01

    Among the many natural hazards affecting the island of Cuba, the hydro-meteorological hazards include extreme rainstorms, tropical cyclones and hurricanes. At Cuba, as in the rest of the Caribbean Islands, the cyclonic period generally starts at the beginning of June and ends in late November; during this time period, hurricanes represent the most powerful expression of the tropical cyclones. As shown by historical data, the effects of hurricanes interest the whole island, with a particular focus at its western regions. Intensity of these events causes severe damage to the environment and the society. Hurricanes are classified into five categories according to the Saffir-Simpson Hurricane Scale, essentially on the basis of the velocity reached by the winds. In this scale, category I is the less intense, and V the highest. In 2008, two strong hurricanes affected the province of Pinar del Rio, in western Cuba, during August and September, with a 10-days interval between the two events. Many effects were produced by the passage of the hurricanes, especially in the karst areas of the Viñales National Park. The first hurricane (named Gustavo) was registered on August 30, 2008. Classified as category IV, it hit the area with wind velocities over 250 km/h, gusts over 300 km/h, and a total rainfall of approximately 100 mm. The hurricane affected the southern slope of the area of mogotes, that is the isolated cone or tower left by intense development of karst processes in tropical climate conditions. The vegetation cover was strongly hit, and largely stripped away, thus exposing several situations of hazards in karst that were previously undetected. Local flooding was also recorded, generally in the lowest topographic areas, and with short duration, due to bedrock characteristics. Ten days after Gustavo, the second hurricane (named Ike) affected the whole Cuba on September 9, 2008. Even though classified as category I, it caused severe damage to the man-made environment

  17. Source to sink characterization of dissolved organic matter in a tropical karst system

    NASA Astrophysics Data System (ADS)

    Lechleitner, Franziska; Lang, Susan Q.; McIntyre, Cameron; Baldini, James U. L.; Dittmar, Thorsten; Eglinton, Timothy I.

    2016-04-01

    Karst systems are widespread surface features present on all continents. They are characterized by complex hydrology with a multitude of possible flow regimes, from diffuse seepage through the host rock to fracture flow in larger conduits. As stalagmite proxy records are important indicators of past terrestrial climate conditions, detailed understanding of the biogeochemistry of cave systems and their relationships to the overlying karst network is crucial. Microbial communities that drive the carbon cycle in caves are nourished by dissolved organic matter (DOM) carried with water into the cave system. Water samples from the Yok Balum cave in Belize were collected for DOM analysis, including soil waters, drip waters and pool waters from inside the cave. Additionally, DOM extracts from a stalagmite from the same cave were analysed to examine DOM signatures and test their applicability for reconstruction of environmental conditions. Ultrahigh-resolution mass spectrometry (via the ESI-FT-ICR-MS technique) yielded detailed molecular fingerprints on DOM from these samples. Several thousand molecular formulae of DOM compounds were identified. In addition, radiocarbon analyses were performed on the DOM samples to gain information on karst turnover times. A principal component analysis of the molecular data revealed a clear gradient between soil waters and cave waters, as soil waters were enriched in highly unsaturated oxygen-rich compounds (typical for vascular plants), which were much less abundant in drip waters. Conversely, peptides, which can originate from bacterial processes, were present only in the drip waters. Our data clearly show connectivity between the cave and overlaying soils, and reworking of DOM by the cave bacterial community. Furthermore, we found molecular evidence for the selective removal of vascular plant-derived DOM in the caves, possibly due to abiotic interactions with minerals.

  18. Ratosa playa lake in southern Spain. Karst pan or compound sink?

    PubMed

    Rodríguez-Rodríguez, Miguel; Martos-Rosillo, Sergio; Pedrera, Antonio; Benavente-Herrera, José

    2015-04-01

    In Andalusia (Spain), there are more than 45 semiarid playa lakes protected as natural reserves and related to karstic outcrops. Some of them are located over regional karstic aquifers and have internal drainage networks with sporadic surface outlets, such as sinkholes (compound sinks), but the majority of such playas have no internal drainage systems, so the only water output is evaporation (karst pans). Karst pans are perched and disconnected from the groundwater system. The fact that the Ratosa playa lake is partially located over a karstic Sierra, as well as other hydromorphological observations, it is suggested that the system could be of a compound type, but a detailed hydrogeological analysis showed that the playa is disconnected from the aquifer, so it is in fact a karst pan. Once the hydrological functioning had been established, a monthly water balance for a 10-year period (1998-2008), enabled us to reproduce the evolution of the water level of the playa lake. Estimations of runoff were carried out by a soil water estimate for a water holding capacity in the soil of 191 mm. Results show a good correlation (>90%) after calibration with the time series of water level in the lake for the same period confirming geological observations. Our results highlight that this water body is extremely vulnerable to hydrological alterations of its watershed caused by human activities, particularly those related to land-use change for agriculture. For this reason, we propose a new protection zone, based on hydrological knowledge, instead of the present Peripheral Area of Protection. PMID:25810083

  19. A model of depressional wetland formation in low-relief karst landscapes

    NASA Astrophysics Data System (ADS)

    Heffernan, J. B.; Murray, A. B.; Cohen, M. J.; Martin, J. B.; Mclaughlin, D. L.; Bianchi, T. S.; Watts, A.

    2014-12-01

    Karst landscapes are formed by the self-reinforcing dissolution of limestone and other soluble rocks, and these positive feedbacks can create a variety of landforms depending on initial topography, climate, bedrock characteristics, and potentially, the activity of biota. In Big Cypress National Preserve (BICY), a low-relief karst landscape in southwestern FL (USA), depressional wetlands, are interspersed within an upland matrix in a regular pattern. This landscape is characterized by over-dispersion of wetland patches, periodic variation in bedrock depth and soil thickness, and distinct bi-modality of these and other soil properties. We hypothesize that the structure of the BICY landscape reflects the concurrent effects of local positive feedbacks among hydroperiod, vegetation productivity and bedrock dissolution; these local processes may ultimately be constrained by landscape scale limitations of water volume. We further hypothesize that low relief and shallow water tables are essential boundary conditions for the emergence of regular patterning of wetlands. To explore these hypotheses, we have developed a quasi-spatial model of a single nascent wetland and its catchment, where the expansion of the wetland basin is driven by acidity associated with belowground root production and aquatic metabolism and their effects on carbonate mineral dissolution, and by the lateral and vertical discharge of water between wetlands and bedrock porosity. This model can, depending on boundary conditions, recreate a range of karst features, including vertical dissolution holes, extensive wetlands that overtake the entire basin, or smaller wetlands whose size equilibrates at a small proportion of the catchment area. This last endpoint, a landform similar to those observed in BICY, occurs only in response to relatively shallow water tables, limited hydrologic inputs, and strong positive feedbacks of biotic activity on dissolution.

  20. Carbonic anhydrase: a key regulatory and detoxifying enzyme for Karst plants.

    PubMed

    Müller, Werner E G; Qiang, Li; Schröder, Heinz C; Hönig, Natalie; Yuan, Daoxian; Grebenjuk, Vlad A; Mussino, Francesca; Giovine, Marco; Wang, Xiaohong

    2014-01-01

    Karstification is a rapid process during which calcidic stones/limestones undergo dissolution with the consequence of a desertification of karst regions. A slow-down of those dissolution processes of Ca-carbonate can be approached by a reforestation program using karst-resistant plants that can resist alkaline pH and higher bicarbonate (HCO₃⁻) concentrations in the soil. Carbonic anhydrases (CA) are enzymes that mediate a rapid and reversible interconversion of CO₂ and HCO₃⁻. In the present study, the steady-state expression of a CA gene, encoding for the plant carbonic anhydrase from the parsley Petroselinum crispum, is monitored. The studies were primarily been performed during germination of the seeds up to the 12/14-day-old embryos. The CA cDNA was cloned. Quantitative polymerase chain reaction (qPCR) analysis revealed that the gene expression level of the P. crispum CA is strongly and significantly affected at more alkaline pH in the growth medium (pH 8.3). This abolishing effect is counteracted both by addition of HCO₃⁻ and by addition of polyphosphate (polyP) to the culture medium. In response to polyP, the increased pH in the vacuoles of the growing plants is normalized. The effect of polyP let us to propose that this polymer acts as a buffer system that facilitates the adjustment of the pH in the cytoplasm. In addition, it is proposed that polyP has the potential to act, especially in the karst, as a fertilizer that allows the karstic plants to cope with the adverse pH and HCO₃⁻ condition in the soil. PMID:24385198

  1. Equivalent Porous Media (EPM) Simulation of Groundwater Hydraulics and Contaminant Transport in Karst Aquifers

    PubMed Central

    Ghasemizadeh, Reza; Yu, Xue; Butscher, Christoph; Hellweger, Ferdi; Padilla, Ingrid; Alshawabkeh, Akram

    2015-01-01

    Karst aquifers have a high degree of heterogeneity and anisotropy in their geologic and hydrogeologic properties which makes predicting their behavior difficult. This paper evaluates the application of the Equivalent Porous Media (EPM) approach to simulate groundwater hydraulics and contaminant transport in karst aquifers using an example from the North Coast limestone aquifer system in Puerto Rico. The goal is to evaluate if the EPM approach, which approximates the karst features with a conceptualized, equivalent continuous medium, is feasible for an actual project, based on available data and the study scale and purpose. Existing National Oceanic Atmospheric Administration (NOAA) data and previous hydrogeological U. S. Geological Survey (USGS) studies were used to define the model input parameters. Hydraulic conductivity and specific yield were estimated using measured groundwater heads over the study area and further calibrated against continuous water level data of three USGS observation wells. The water-table fluctuation results indicate that the model can practically reflect the steady-state groundwater hydraulics (normalized RMSE of 12.4%) and long-term variability (normalized RMSE of 3.0%) at regional and intermediate scales and can be applied to predict future water table behavior under different hydrogeological conditions. The application of the EPM approach to simulate transport is limited because it does not directly consider possible irregular conduit flow pathways. However, the results from the present study suggest that the EPM approach is capable to reproduce the spreading of a TCE plume at intermediate scales with sufficient accuracy (normalized RMSE of 8.45%) for groundwater resources management and the planning of contamination mitigation strategies. PMID:26422202

  2. Impact of the lithographic discontinuities on the karst conduit development - insights from modelling

    NASA Astrophysics Data System (ADS)

    Petrus, Karine; Szymczak, Piotr

    2016-04-01

    Karst formation is controlled by the processes of the fluid flow and reactant transport coupled to the chemical erosion of the limestone rock [1]. The coupling between these processes can lead to a number of different instabilities, resulting in the formation of dissolutional voids, caverns and conduits. Arguably the simplest systems of this kind are solution pipes, in which gravitationally driven water movement carves vertical conduits in limestone rocks. In the homogeneous rocks these conduits are often cylindrical, with almost a constant diameter along their length. However, in a stratified medium, the morphology of the pipes changes. For example, if a number of less porous layers is introduced in an otherwise homogeneous medium, then the pipes are observed to narrow as they cross the layers and then widen up to form bulbous caverns as they emerge from the layer [1]. In this communication, we investigate these effects more closely, considering different kind of lithographic discontinuities to be present in the system: the layers of increased/decreased porosity and/or permeability as well as the solubility which is different from the rest of the system. Using a Darcy-scale numerical model we analyze the effects these layers have on the shape and growth of solution pipes and compare the results on the piping morphologies observed in nature. Finally we comment on the possible relevance of these results to the cave-formation phenomena and the inception horizon concept [3]. References: 1.Howard A. D., The development of karst features, Bull. Natl. Spel. Soc. 25, 45-65 (1963) 2. Petrus, K. and Szymczak, P., Influence of layering on the formation and growth of solution pipes. Frontiers in Physics (submitted) 3.Filipponi , M., Jeannin, P. and Tacher, L., Evidence of inception horizons in karst conduit networks, Geomorphology, 106, 86-99 (2009)

  3. Ratosa playa lake in southern Spain. Karst pan or compound sink?

    PubMed

    Rodríguez-Rodríguez, Miguel; Martos-Rosillo, Sergio; Pedrera, Antonio; Benavente-Herrera, José

    2015-04-01

    In Andalusia (Spain), there are more than 45 semiarid playa lakes protected as natural reserves and related to karstic outcrops. Some of them are located over regional karstic aquifers and have internal drainage networks with sporadic surface outlets, such as sinkholes (compound sinks), but the majority of such playas have no internal drainage systems, so the only water output is evaporation (karst pans). Karst pans are perched and disconnected from the groundwater system. The fact that the Ratosa playa lake is partially located over a karstic Sierra, as well as other hydromorphological observations, it is suggested that the system could be of a compound type, but a detailed hydrogeological analysis showed that the playa is disconnected from the aquifer, so it is in fact a karst pan. Once the hydrological functioning had been established, a monthly water balance for a 10-year period (1998-2008), enabled us to reproduce the evolution of the water level of the playa lake. Estimations of runoff were carried out by a soil water estimate for a water holding capacity in the soil of 191 mm. Results show a good correlation (>90%) after calibration with the time series of water level in the lake for the same period confirming geological observations. Our results highlight that this water body is extremely vulnerable to hydrological alterations of its watershed caused by human activities, particularly those related to land-use change for agriculture. For this reason, we propose a new protection zone, based on hydrological knowledge, instead of the present Peripheral Area of Protection.

  4. Bryophyte communities as biomonitors of environmental factors in the Goujiang karst bauxite, southwestern China.

    PubMed

    Wang, Shiqiang; Zhang, Zhaohui; Wang, Zhihui

    2015-12-15

    Bauxite mining on karst results in several ecological and environmental issues including heavy metal pollution, soil erosion and the destruction of vegetation. In turn, these may affect the distribution of plant communities and endanger human health. In general, bryophytes (mosses, liverworts and hornworts) are pioneer plants, lacking roots, vascular systems and well-developed cuticles. Due to their high sensitivity to the environment, they are often used to monitor air and soil pollution. A total of 25 bryophyte taxa from 19 genera and 9 families were recorded on Goujiang karst bauxite near the city of Zunyi in the Guizhou Province of southwestern China. Eleven principal bryophyte communities were identified, most of which consisted of only one species (monospecific assemblage), although the proportion of these single-species communities differed at the six locations. The levels of heavy metals also differed in soil from the six locations: iron, 8748.9-10,023μg/g; zinc, 146.7-240.9μg/g; copper, 24.6-60.4μg/g; and nickel, 35.6-95.1μg/g. A canonical correspondence analysis (CCA) of the bryophyte communities and environmental variables revealed the effect of gradient (slope), altitude and heavy metals in the soil on the distribution of the principal bryophyte communities. More than 36% of bryophyte taxa identified reproduced asexually by gemmae, as gemmiferous bryophyte communities tolerate substrates with high levels of heavy metals more readily than non-gemmiferous communities do. The distribution of heavy metals in the soil is reflected in the distribution of the bryophyte communities. The distribution characteristics of the principal bryophyte communities and of the gemmiferous bryophyte communities are useful in monitoring heavy metal pollution in karst bauxite.

  5. Equivalent Porous Media (EPM) Simulation of Groundwater Hydraulics and Contaminant Transport in Karst Aquifers.

    PubMed

    Ghasemizadeh, Reza; Yu, Xue; Butscher, Christoph; Hellweger, Ferdi; Padilla, Ingrid; Alshawabkeh, Akram

    2015-01-01

    Karst aquifers have a high degree of heterogeneity and anisotropy in their geologic and hydrogeologic properties which makes predicting their behavior difficult. This paper evaluates the application of the Equivalent Porous Media (EPM) approach to simulate groundwater hydraulics and contaminant transport in karst aquifers using an example from the North Coast limestone aquifer system in Puerto Rico. The goal is to evaluate if the EPM approach, which approximates the karst features with a conceptualized, equivalent continuous medium, is feasible for an actual project, based on available data and the study scale and purpose. Existing National Oceanic Atmospheric Administration (NOAA) data and previous hydrogeological U. S. Geological Survey (USGS) studies were used to define the model input parameters. Hydraulic conductivity and specific yield were estimated using measured groundwater heads over the study area and further calibrated against continuous water level data of three USGS observation wells. The water-table fluctuation results indicate that the model can practically reflect the steady-state groundwater hydraulics (normalized RMSE of 12.4%) and long-term variability (normalized RMSE of 3.0%) at regional and intermediate scales and can be applied to predict future water table behavior under different hydrogeological conditions. The application of the EPM approach to simulate transport is limited because it does not directly consider possible irregular conduit flow pathways. However, the results from the present study suggest that the EPM approach is capable to reproduce the spreading of a TCE plume at intermediate scales with sufficient accuracy (normalized RMSE of 8.45%) for groundwater resources management and the planning of contamination mitigation strategies.

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

    NASA Astrophysics Data System (ADS)

    Karami, Gholam Hossein; Bagheri, Rahim; Rahimi, Fahimeh

    2016-08-01

    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.

  7. Bryophyte communities as biomonitors of environmental factors in the Goujiang karst bauxite, southwestern China.

    PubMed

    Wang, Shiqiang; Zhang, Zhaohui; Wang, Zhihui

    2015-12-15

    Bauxite mining on karst results in several ecological and environmental issues including heavy metal pollution, soil erosion and the destruction of vegetation. In turn, these may affect the distribution of plant communities and endanger human health. In general, bryophytes (mosses, liverworts and hornworts) are pioneer plants, lacking roots, vascular systems and well-developed cuticles. Due to their high sensitivity to the environment, they are often used to monitor air and soil pollution. A total of 25 bryophyte taxa from 19 genera and 9 families were recorded on Goujiang karst bauxite near the city of Zunyi in the Guizhou Province of southwestern China. Eleven principal bryophyte communities were identified, most of which consisted of only one species (monospecific assemblage), although the proportion of these single-species communities differed at the six locations. The levels of heavy metals also differed in soil from the six locations: iron, 8748.9-10,023μg/g; zinc, 146.7-240.9μg/g; copper, 24.6-60.4μg/g; and nickel, 35.6-95.1μg/g. A canonical correspondence analysis (CCA) of the bryophyte communities and environmental variables revealed the effect of gradient (slope), altitude and heavy metals in the soil on the distribution of the principal bryophyte communities. More than 36% of bryophyte taxa identified reproduced asexually by gemmae, as gemmiferous bryophyte communities tolerate substrates with high levels of heavy metals more readily than non-gemmiferous communities do. The distribution of heavy metals in the soil is reflected in the distribution of the bryophyte communities. The distribution characteristics of the principal bryophyte communities and of the gemmiferous bryophyte communities are useful in monitoring heavy metal pollution in karst bauxite. PMID:26312404

  8. Estimation of baseflow and water transfer in karst catchments in Mediterranean Turkey by nonlinear recession analysis

    NASA Astrophysics Data System (ADS)

    Eris, Ebru; Wittenberg, Hartmut

    2015-11-01

    Because of water transfers through fissures, cavities, caves and phreatic channels of various sizes and unknown directions, the topographic watersheds of karst catchments have little significance for their aquifers. Most of the flow in the Manavgat River in South Anatolia has its origin outside of the surface watershed and is transferred through karst pathways. Previous investigations found evidence for this by groundwater tracing techniques. In this study, flow recession analysis and baseflow separation are applied to the time series of daily flows 1992-2008 from three gauging stations. Flow recessions were found corresponding to the nonlinear storage-baseflow relationship S = a·Qb, with b values around 0.5 as typical for unconfined groundwater, while the coefficient a showed marked seasonal variations with higher values in the rainy winter time and decreasing values towards the dry summer. For catchments which receive water transfers from other areas, the decrease of a is retarded. Flow recession is slower since more water is available. Baseflow separation by using the same nonlinear model revealed that direct flow, which is mainly surface flow, corresponds roughly to the surface catchments while baseflow, which accounts for most of the total flow, is highly influenced by transfers from karst sink areas outside the surface watersheds. The subsurface transfer was simulated by a nonlinear reservoir routing algorithm. Time series of monthly baseflow from catchments which receive transfer water were compared with those of sinkhole (loss) areas. The procedure allows inferring the origin area of the inflows and estimating the retention or lag time of the transfer.

  9. Multi-scale hydrogeological and hydrogeophysical approach to monitor vadose zone hydrodynamics of a karst system

    NASA Astrophysics Data System (ADS)

    Watlet, Arnaud; Poulain, Amaël; Van Camp, Michel; Francis, Olivier; Triantafyllou, Antoine; Rochez, Gaëtan; Hallet, Vincent; Kaufmann, Olivier

    2016-04-01

    The vadose zone of karst systems plays an important role on the water dynamics. In particular, temporary perched aquifers can appear in the subsurface due to changes of weather conditions, reduced evapotranspiration and the vertical gradients of porosity and permeability. Although many difficulties are usually encountered when studying karst environments due to their heterogeneities, cave systems offer an outstanding opportunity to investigate vadose zone from the inside. We present a multi-scale study covering two years of hydrogeological and geophysical monitoring of the Lomme Karst System (LKS) located in the Variscan fold-and-thrust belt (Belgium), a region (~ 3000 ha) that shows many karstic networks within Devonian limestone units. Hydrogeological data cover the whole LKS and involve e.g. flows and levels monitoring or tracer tests performed in both vadose and saturated zones. Such data bring valuable information on the hydrological context of the studied area at the catchment scale. Combining those results with geophysical measurements allows validating and imaging them at a smaller scale, with more integrative techniques. Hydrogeophysical measurements are focused on only one cave system of the LKS, at the Rochefort site (~ 40 ha), taking benefit of the Rochefort Cave Laboratory (RCL) infrastructures. In this study, a microgravimetric monitoring and an Electrical Resistivity Tomography (ERT) monitoring are involved. The microgravimetric monitoring consists in a superconducting gravimeter continuously measuring gravity changes at the surface of the RCL and an additional relative gravimeter installed in the underlying cave located 35 meters below the surface. While gravimeters are sensible to changes that occur in both the vadose zone and the saturated zone of the whole cave system, combining their recorded signals allows enhancing vadose zone's gravity changes. Finally, the surface ERT monitoring provide valuable information at the (sub)-meter scale on the

  10. Effects of fire on soil CO2 - Implications for karst processes

    NASA Astrophysics Data System (ADS)

    Coleborn, K.; Spate, A.; Tozer, M.; Treble, P. C.; Andersen, M. S.; Fairchild, I. J.; Baker, A.; Meehan, S.; Baker, A.

    2014-12-01

    Fire reduces soil CO2 concentration by destroying vegetation and soil dwelling microbial communities thus reducing both heterotrophic and autotrophic contributions to soil respiration. While reductions in microbial respiration are short-lived, root respiration can take longer to recover, depending on the dominant growth forms (e.g. trees vs herbs) and modes of post-fire recovery (e.g. resprouting vs seedling establishment). This study aimed to quantify whether soil CO2 concentration was reduced ~5 years and ~10 years after a fire in a subalpine karst environment in south-eastern Australia and to consider the implications for karst dissolution processes and speleothem growth rate. Paired sites with burnt and unburnt soil were compared with regards to CO2 concentrations, soil moisture and soil temperature. Samples were taken from a grassland site and woodland site burnt ~5 years ago and a woodland site burnt ~10 years ago. The results showed that soil respiration was depressed in burnt sites relative to the unburnt pair in both the grassland and woodland sites after ~5 years; however, after ~10 years there was no significant difference between the burnt and control woodland sites. This indicates that soil CO2 concentration takes between 5-10 years to return to pre-fire levels in subalpine environments in south-eastern Australia. In a karst environment, this long-term reduction in soil CO2 concentration caused by fire is likely to cause a decreased stalagmite growth that could be incorrectly attributed to multiannual climatic drying, such as the El Nino Southern Oscillation, when reconstructing past environmental change from stalagmite records.

  11. Source, variability, and transformation of nitrate in a regional karst aquifer: Edwards aquifer, central Texas.

    USGS Publications Warehouse

    Musgrove, Marylynn; Opsahl, Stephen P.; Mahler, Barbara J.; Herrington, Chris; Sample, Thomas; Banta, John (Ryan)

    2016-01-01

    Many karst regions are undergoing rapid population growth and expansion of urban land accompanied by increases in wastewater generation and changing patterns of nitrate (NO3−) loading to surface and groundwater. We investigate variability and sources of NO3− in a regional karst aquifer system, the Edwards aquifer of central Texas. Samples from streams recharging the aquifer, groundwater wells, and springs were collected during 2008–12 from the Barton Springs and San Antonio segments of the Edwards aquifer and analyzed for nitrogen (N) species concentrations and NO3− stable isotopes (δ15N and δ18O). These data were augmented by historical data collected from 1937 to 2007. NO3− concentrations and discharge data indicate that short-term variability (days to months) in groundwater NO3− concentrations in the Barton Springs segment is controlled by occurrence of individual storms and multi-annual wet-dry cycles, whereas the lack of short-term variability in groundwater in the San Antonio segment indicates the dominance of transport along regional flow paths. In both segments, longer-term increases (years to decades) in NO3− concentrations cannot be attributed to hydrologic conditions; rather, isotopic ratios and land-use change indicate that septic systems and land application of treated wastewater might be the source of increased loading of NO3−. These results highlight the vulnerability of karst aquifers to NO3− contamination from urban wastewater. An analysis of N-species loading in recharge and discharge for the Barton Springs segment during 2008–10 indicates an overall mass balance in total N, but recharge contains higher concentrations of organic N and lower concentrations of NO3−than does discharge, consistent with nitrification of organic N within the aquifer and consumption of dissolved oxygen. This study demonstrates that subaqueous nitrification of organic N in the aquifer, as opposed to in soils, might be a previously

  12. Geological contribution to the GHG budget of the Capo Caccia karst ecosystem (NW Sardinia, Italy)

    NASA Astrophysics Data System (ADS)

    Sanna, Laura; Arca, Angelo; Casula, Marcello; Ventura, Andrea; Zara, Pierpaolo; Duce, Pierpaolo

    2016-04-01

    Capo Caccia karst area (North-West Sardinia, Italy) is one of the monitoring points of the Italian ICOS infrastructure. The carbon flux in this region is continuously performed by direct measurement of gas exchanges across canopy-atmosphere interface using an eddy covariance tower placed over a Mediterranean maquis, constituted by sclerophyl species. As the net ecosystem carbon balance in this terrestrial ecosystem does not only respond to physiological features of its vegetation, the geological contribution to the GHG budget has been investigated through the relationships among atmosphere-biosphere-geosphere gas exchanges. Since carbon dioxide is involved in the geochemical cycle of the karst processes, the environmental monitoring programme has been extended to the underground atmosphere using micrometeorological stations installed within caves. The preliminary data show a static cave air CO2 concentration ranging from 500 ppm to 1600 ppm, with periodic gas plumes that reach up to 18,000 ppm. Correlation analysis point out that subsurface-atmosphere gas exchange reflects environmental forcing related to atmospheric variables. In fact the degassing mainly occurs by barometric pressure changes and via density driven flow. Subsurface air ventilation can be also induced by water table oscillations, so future step of the study will take into account the relationship between the unsatured zone and the near marine ecosystem. Even though underground air mass is reasonably small respect to the outside atmosphere, when considering the high density of karst features of Capo Caccia karst ecosystem, its temporal CO2 pattern provides evidence that the amounts of carbon that might be released from subsurface could be noticeable at both local and regional scale. Integrated monitoring of atmosphere dynamic can give clues for understanding carbon cycle model and multidisciplinary approaches contribute for filling the gap in global carbon budget. Acknowledgements This research was

  13. Natural hazards in the karst areas of the Viñales National Park, Cuba

    NASA Astrophysics Data System (ADS)

    Govea Blanco, Darlenys; Farfan Gonzalez, Hermes; Dias Guanche, Carlos; Parise, Mario; Ramirez, Robert

    2010-05-01

    Cuban karst is subject to several natural hazards, the great majority of which is hydro-meteorological in character: intense rainstorms, tropical cyclones, seawater inundation, etc. A further, serious problem is represented by droughts, that have become very severe during the recent years, due to longer persistence of the dry season. Beside these hazards, seismic shocks in the eastern part of the country, and mass movements in the mountain areas have also to be mentioned. In general, it has to be noted that both casualties and economic losses from natural disasters have slowly decreased during the last decades at Cuba. Viñales National Park, as many other natural landforms in the Cuban karst, has a great potential for development and exploitation in several different fields, from agriculture, to tourism and recreational activities. At these aims, it is necessary to preserve the natural landscape, its beauty and resources, and, at the same time, improve the quality of people living in these environments. In particular, to face the social changes at present occurring in the area is one of the most difficult task for those people that are in charge of land management and development. It has also to be remembered that "Valle de Viñales" has been included by UNESCO in the World Cultural Heritage List. The main scenarios of natural hazards in the Viñales National Park are described in this contribution, and analyzed by means of different methodologies. Flooded areas have been mapped in the field soon after the occurrence of an extreme event as the hurricane Ike, characterized by rainfall higher than 300 mm/day, and preceded only ten days before by hurricane Gustav, that discharged in the area an amount of 120 mm/day of rain. As a consequence of the temporal vicinity of the two events, the terranes were already highly saturated at the time of occurrence of hurricane Ike, which thus resulted to be one of the most extreme floods ever recorded in the area. Electrostatic

  14. Analysis of TCE Fate and Transport in Karst Groundwater Systems Using Statistical Mixed Models

    NASA Astrophysics Data System (ADS)

    Anaya, A. A.; Padilla, I. Y.

    2012-12-01

    Karst groundwater systems are highly productive and provide an important fresh water resource for human development and ecological integrity. Their high productivity is often associated with conduit flow and high matrix permeability. The same characteristics that make these aquifers productive also make them highly vulnerable to contamination and a likely for contaminant exposure. Of particular interest are trichloroethylene, (TCE) and Di-(2-Ethylhexyl) phthalate (DEHP). These chemicals have been identified as potential precursors of pre-term birth, a leading cause of neonatal complications with a significant health and societal cost. Both of these contaminants have been found in the karst groundwater formations in this area of the island. The general objectives of this work are to: (1) develop fundamental knowledge and determine the processes controlling the release, mobility, persistence, and possible pathways of contaminants in karst groundwater systems, and (2) characterize transport processes in conduit and diffusion-dominated flow under base flow and storm flow conditions. The work presented herein focuses on the use of geo-hydro statistical tools to characterize flow and transport processes under different flow regimes, and their application in the analysis of fate and transport of TCE. Multidimensional, laboratory-scale Geo-Hydrobed models (GHM) were used for this purpose. The models consist of stainless-steel tanks containing karstified limestone blocks collected from the karst aquifer formation of northern Puerto Rico. The models integrates a network of sampling wells to monitor flow, pressure, and solute concentrations temporally and spatially. Experimental work entails injecting dissolved CaCl2 tracers and TCE in the upstream boundary of the GHM while monitoring TCE and tracer concentrations spatially and temporally in the limestone under different groundwater flow regimes. Analysis of the temporal and spatial concentration distributions of solutes

  15. [Soil fertility characteristics under different land use patterns in depressions between karst hills].

    PubMed

    Liu, Yan; Song, Tong-Qing; Cai, De-Suo; Zeng, Fu-Ping; Peng, Wan-Xia; Du, Hu

    2014-06-01

    Soil samples were collected from the depressions between karst hills by grid sampling method (5 m x 5 m), soil pH, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) in surface layer (0-20 cm) under different land use patterns (burning, cutting, cutting plus root removal, enclosure, maize plantation, and pasture plantation) were measured, the main factors of influencing the soil fertility was identified by principal component analysis (PCA), and the relationships between soil nutrients and microorganisms were demonstrated by canonical correlation analysis (CCA). The results showed that the soil was slightly alkaline (pH 7.83-7.98), and the soil fertility differed under the different land use patterns, with 76.78-116.05 g x kg(-1) of SOC, 4.29-6.23 g x kg(-1) of TN, 1.15-1.47 g x kg(-1) of TP, 3.59-6.05 g x kg(-1) of TK, 331.49-505.49 mg x kg(-1) of AN), 3.92-10.91 mg x kg(-1) of AP, and 136.28-198.10 mg x kg(-1) of AK. These soil indexes except pH showed moderate or strong variation. Different land use patterns had various impacts on soil fertility: Soil nutrients such as SOC, TN, TP, and AN were most significantly influenced by land use patterns in the depressions between karst hills; Followed by soil microorganisms, especially soil actinomycetes, and the effect decreased with the increasing gradient of human disturbance from enclosure, burning, cutting, cutting plus root removal, pasture plantation, and maize plantation. CCA elucidated that considerable interactions existed in soil TP with MBP (microbial biomass phosphorus), TK with MBC (microbial biomass carbon), TN with actinomycetes in the burned area, while TN and MBC in the cutting treatment, AP and MBN (microbial biomass nitrogen) in the treatment of cutting plus root removal, pH with MBC and fungus in the enclosure treatment, TN and TK with MBP in the maize plantation, pH with fungi

  16. Trade-offs among ecosystem services in a typical Karst watershed, SW China.

    PubMed

    Tian, Yichao; Wang, Shijie; Bai, Xiaoyong; Luo, Guangjie; Xu, Yan

    2016-10-01

    Nowadays, most research results on ecosystem services in Karst areas are limited to a single function of an ecosystem service. Few scholars conduct a comparative study on the mutual relationships among ecosystem services, let alone reveal the trade-off and synergic relationships in typical Karst watershed. This research aims to understand and quantitatively evaluate the relationships among ecosystem services in a typical Karst watershed, broaden the depth and width of trade-off and synergic relationships in ecosystem services and explore a set of technical processes involved in these relationships. With the Shibantang Karst watershed in China as the research site, we explore the trade-off and synergic relationships of net primary productivity (NPP), water yield, and sediment yield by coupling Soil and Water Assessment Tool (SWAT) and Carnegie-Ames-Stanford Approach (CASA), and simulating and evaluating these three ecosystem services between 2000 and 2010. Results of this study are as follows. (1) The annual average water yield decreased from 528mm in 2000 to 513mm in 2010, decreasing by 2.84%. (2) The annual average sediment yield decreased from 26.15t/ha in 2000 to 23.81t/ha in 2010, with an average annual reduction of 0.23t/ha. (3) The annual average NPP increased from 739.38gCm(-2)a(-1) in 2000 to 746.25gCm(-2)a(-1) in 2010, increasing by 6.87gCm(-2)a(-1) . (4) Water yield and sediment yield are in a synergic relationship. The increase of water yield can accumulate the soil erosion amount. NPP is in a trade-off relationship with water yield and sediment yield. The improvement of NPP is good for decreasing water yield and soil erosion amount and increasing soil conservation amount. This study provides policy makers and planners an approach to develop an integrated model, as well as design mapping and monitoring protocols for land use change and ecosystem service assessments.

  17. Hydrological monitoring of experimental karst catchment Sutina - Karakašica

    NASA Astrophysics Data System (ADS)

    Bonacci, O.; Andrić, I.

    2012-04-01

    The Sutina - Karakašica is an ungauged karst catchment in southern part of Croatia with relative small area but with existing records of several events of flash flood that compromised the structures as bridge and roads along the stream. This poster gives an overview of the creation of the experimental catchment and establishment of the hydrological monitoring system which has for a goal a better understanding of runoff processes within the experimental karst area as well as flash flood occurrence analysis. The studied catchment is located in Dalmatia, southern part of Croatia, a region of Dinaric karst. Although it is very difficult to determine catchment borders in the karstic terrain, for the porpoises of the study the area of the catchment is estimated to 8 km2. The length of the stream flow up to the control cross section is 4.4 km. The highest point of the studied catchment area is on the 941 m a.s.l. and the lowest at the 300 m a.s.l. The geological settings of the catchment are characterized by the sedimentary rocks, mostly limestone and dolomites with discontinuities (cracks, and fractures) filled up with terra rossa and breccias. The presence of mudstone patches in the surface ensures the continuous surface flow of the studied stream. Some caves are also to be found in the catchment area. In the karst watersheds the occurrence of flash floods can be registered due to the exceptional meteorologic events during the year. The intensive rainfall in the short time period can trigger a flash flood that can induce overbank flow, immense changes in channel morphology and in sediment distribution. In order to produce a hydrological model that could predict the events of flash flood in the studied area, a continuous monitoring of meteorological and hydrological parameters in the catchment is established. The predictions of exceptional flooding events derived from a useful hydrological model based on the study site can be used further on to quantify the possible

  18. Carbon Exchange and Water Use in Karst Landscapes: Impact of Woody Encroachment

    NASA Astrophysics Data System (ADS)

    Heilman, J. L.; Litvak, M. E.

    2008-05-01

    Woody plant invasion into grasslands and savannas, and its impact on water use are critical issues in karst landscapes because 25% of the world's population obtains its water from karst aquifers. It is well documented that woody encroachment increases carbon sequestration, but its impact on water use is less clear. It is widely presumed that woody plants increase evapotranspiration (ET), in part because deep root systems provide access to a more stable supply of water than what is available to grasses. If this is true, woody encroachment should reduce the sensitivity of carbon exchange and ET to rainfall pulses and water deficits, and vulnerability to drought. Since 2004, we have been investigating, via eddy covariance, carbon exchange and water use on a grassland, a savanna with approximately 35% woody cover, and a dense live oak-Ashe juniper forest on the karst Edwards Plateau in south and west central Texas. The Plateau is a 93,000 km2 karst ecoregion that is dominated by live oak-Ashe juniper savannas underlain by mixed C3/C4 grasses, and soils are generally shallow. The Plateau contains the Edwards Aquifer which supplies drinking water to over 2 million people, and is home to a number of threatened and endangered species, many of them aquatic. Populations of juniper are expanding due to suppression of wildfires, and public funds are being spent to remove juniper in an attempt to increase water availability. Our measurements show large differences in carbon sequestration among the ecosystems (highest in savanna and lowest in grassland), and small differences in ET (~0.2 mm day-1 higher in the forest than in the grassland). We attribute increased ET to increases in net radiation, and proportionally greater partitioning of available energy into sensible heat flux at the expense of latent heat flux. We found little differences in response of carbon exchange and ET to rainfall and water deficits, regardless of the amount of woody cover, intensity of rainfall, or

  19. [Soil fertility characteristics under different land use patterns in depressions between karst hills].

    PubMed

    Liu, Yan; Song, Tong-Qing; Cai, De-Suo; Zeng, Fu-Ping; Peng, Wan-Xia; Du, Hu

    2014-06-01

    Soil samples were collected from the depressions between karst hills by grid sampling method (5 m x 5 m), soil pH, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) in surface layer (0-20 cm) under different land use patterns (burning, cutting, cutting plus root removal, enclosure, maize plantation, and pasture plantation) were measured, the main factors of influencing the soil fertility was identified by principal component analysis (PCA), and the relationships between soil nutrients and microorganisms were demonstrated by canonical correlation analysis (CCA). The results showed that the soil was slightly alkaline (pH 7.83-7.98), and the soil fertility differed under the different land use patterns, with 76.78-116.05 g x kg(-1) of SOC, 4.29-6.23 g x kg(-1) of TN, 1.15-1.47 g x kg(-1) of TP, 3.59-6.05 g x kg(-1) of TK, 331.49-505.49 mg x kg(-1) of AN), 3.92-10.91 mg x kg(-1) of AP, and 136.28-198.10 mg x kg(-1) of AK. These soil indexes except pH showed moderate or strong variation. Different land use patterns had various impacts on soil fertility: Soil nutrients such as SOC, TN, TP, and AN were most significantly influenced by land use patterns in the depressions between karst hills; Followed by soil microorganisms, especially soil actinomycetes, and the effect decreased with the increasing gradient of human disturbance from enclosure, burning, cutting, cutting plus root removal, pasture plantation, and maize plantation. CCA elucidated that considerable interactions existed in soil TP with MBP (microbial biomass phosphorus), TK with MBC (microbial biomass carbon), TN with actinomycetes in the burned area, while TN and MBC in the cutting treatment, AP and MBN (microbial biomass nitrogen) in the treatment of cutting plus root removal, pH with MBC and fungus in the enclosure treatment, TN and TK with MBP in the maize plantation, pH with fungi

  20. Characterizing aperture distributions in karst aquifers by simulating the evolution of solution conduits

    NASA Astrophysics Data System (ADS)

    Rehrl, C.; Hubinger, B.; Birk, S.

    2009-12-01

    Karst aquifers develop where solutional enlargement of small interconnected openings such as fractures and bedding planes creates highly permeable conduits embedded in the much less permeable fissured porous rock. The hydrogeological characterization of these heterogeneous flow systems can be supported by simulating the evolution of solution conduits. In this work, both generic models representing hypothetical carbonate environments and site-related models referring to the gypsum karst settings of the Western Ukraine are used to examine how the hydrogeological environment determines the evolving aperture distributions. The generic models comprise regular networks of interconnected protoconduits with spatially uncorrelated lognormally distributed apertures of about one millimeter and less. For each model setting several realizations are performed and statistically analyzed. Different hydraulic boundary conditions are considered to account for the limited availability of flow inherent in any type of hydrogeological environment. Thus, the initial hydraulic gradient is reduced with ongoing conduit development such that the predefined maximum flow rate is not exceeded. If the maximum flow rate in the karst system is not strongly limited conduit development is found to be competitive and leads to stable bimodal aperture distributions; only a limited number of conduits continue to grow and the remaining apertures stay small. The number of large-sized conduits tends to decrease with increasing variance of the initial apertures and with decreasing maximum flow rate. However, strongly limited flow rates lead to more uniform aperture distributions. The results from the above-described generic scenarios agree with those from site-related models representing the multi-storey artesian settings of the gypsum karst terrain of the Western Ukraine (Rehrl et al., Water Resourc. Res. 44, W11425). In this type of setting, a soluble unit is sandwiched between less soluble formations and

  1. Modeling turbidity and flow at daily steps in karst using ARIMA/ARFIMA-GARCH error models

    NASA Astrophysics Data System (ADS)

    Massei, N.

    2013-12-01

    Hydrological and physico-chemical variations recorded at karst springs usually reflect highly non-linear processes and the corresponding time series are then very often also highly non-linear. Among others, turbidity, as an important parameter regarding water quality and management, is a very complex response of karst systems to rain events, involving direct transfer of particles from point-source recharge as well as resuspension of particles previously deposited and stored within the system. For those reasons, turbidity modeling has not been well taken in karst hydrological models so far. Most of the time, the modeling approaches would involve stochastic linear models such ARIMA-type models and their derivatives (ARMA, ARMAX, ARIMAX, ARFIMA...). Yet, linear models usually fail to represent well the whole (stochastic) process variability, and their residuals still contain useful information that can be used to either understand the whole variability or to enhance short-term predictability and forecasting. Model residuals are actually not i.i.d., which can be identified by the fact that squared residuals still present clear and significant serial correlation. Indeed, high (low) amplitudes are followed in time by high (low) amplitudes, which can be seen on residuals time series as periods of time during which amplitudes are higher (lower) then the mean amplitude. This is known as the ARCH effet (AutoRegressive Conditional Heteroskedasticity), and the corresponding non-linear process affecting residuals of a linear model can be modeled using ARCH or generalized ARCH (GARCH) non-linear modeling, which approaches are very well known in econometrics. Here we investigated the capability of ARIMA-GARCH error models to represent a ~20-yr daily turbidity time series recorded at a karst spring used for water supply of the city of Le Havre (Upper Normandy, France). ARIMA and ARFIMA models were used to represent the mean behavior of the time series and the residuals clearly

  2. A new small karst-dwelling species of Cyrtodactylus (Reptilia: Squamata: Gekkonidae) from Java, Indonesia.

    PubMed

    Riyanto, Awal; Bauer, Aaron M; Yudha, Donan Satria

    2014-04-07

    A new small karst-dwelling species of the genus Cyrtodactylus is described from East Java and Special Province of Yogyakarta, Indonesia. Cyrtodactylus semiadii sp. nov. is a small species (SVL to 47.1 mm in females, 42.1 mm in males) distinguished from all other congeners by unique characters combination: short, robust, cylindrical tail, indistinct ventrolateral folds, absence of precloacal groove, absence of enlarged femoral scales, absence of precloacal and femoral pores and lack of enlarged median subcaudal scales. It is the third member of the genus recorded from Java. 

  3. Trade-offs among ecosystem services in a typical Karst watershed, SW China.

    PubMed

    Tian, Yichao; Wang, Shijie; Bai, Xiaoyong; Luo, Guangjie; Xu, Yan

    2016-10-01

    Nowadays, most research results on ecosystem services in Karst areas are limited to a single function of an ecosystem service. Few scholars conduct a comparative study on the mutual relationships among ecosystem services, let alone reveal the trade-off and synergic relationships in typical Karst watershed. This research aims to understand and quantitatively evaluate the relationships among ecosystem services in a typical Karst watershed, broaden the depth and width of trade-off and synergic relationships in ecosystem services and explore a set of technical processes involved in these relationships. With the Shibantang Karst watershed in China as the research site, we explore the trade-off and synergic relationships of net primary productivity (NPP), water yield, and sediment yield by coupling Soil and Water Assessment Tool (SWAT) and Carnegie-Ames-Stanford Approach (CASA), and simulating and evaluating these three ecosystem services between 2000 and 2010. Results of this study are as follows. (1) The annual average water yield decreased from 528mm in 2000 to 513mm in 2010, decreasing by 2.84%. (2) The annual average sediment yield decreased from 26.15t/ha in 2000 to 23.81t/ha in 2010, with an average annual reduction of 0.23t/ha. (3) The annual average NPP increased from 739.38gCm(-2)a(-1) in 2000 to 746.25gCm(-2)a(-1) in 2010, increasing by 6.87gCm(-2)a(-1) . (4) Water yield and sediment yield are in a synergic relationship. The increase of water yield can accumulate the soil erosion amount. NPP is in a trade-off relationship with water yield and sediment yield. The improvement of NPP is good for decreasing water yield and soil erosion amount and increasing soil conservation amount. This study provides policy makers and planners an approach to develop an integrated model, as well as design mapping and monitoring protocols for land use change and ecosystem service assessments. PMID:27265738

  4. BIOCHEMICAL MECHANISMS OF RESISTANCE TO p-NITROCHLOROBENZENE OF KARST CAVES MICROORGANISMS.

    PubMed

    Suslova, O S; Rokitko, P V; Bondar, K M; Golubenko, O O; Tashyrev, A B

    2015-01-01

    The biochemical mechanisms of resistance to persistent organic xenobiotic p-nitrochlorobenzene (NCB) of bacterial strains isolated from two cave clays ecosystems-Mushkarova Yama (Podolia, Ukraine) and Kuybyshevskaya (Western Caucasus, Abkhazia) have been established It has been determined that chemoorganotrophic karst caves strains could interact with NCB and transform it reducing the nitro group withformation of p-chloroaniline (ClA) followed by further destruction of NCB aromatic ring. This explained high resistance of caves strains to NCB. The studied strains could potentially be used in wastewater treatment from nitrochloraromatic compounds. PMID:26547961

  5. [Responses of soil properties to ecosystem degradation in Karst region of northwest Guangxi, China].

    PubMed

    Wei, Ya-wei; Su, Yi-rong; Chen, Xiang-bi; He, Xun-yang

    2010-05-01

    Four typical ecosystems, i.e., maize-sweet potato rotational cultivated land (KMS), grazing grassland burned annually in winter (KGB), natural restoration land (KNR), and primary forest land (KPF), in Karst region of northwest Guangxi were selected to investigate the responses of soil nutrients (C, N and P), soil microbial biomass, and soil structure to the degradation of ecosystem. The contents of soil organic C, total N and P, and soil microbial biomass C, N, and P were significantly higher in KPF than in KMS, KGB, and KNR (P < 0.01). In the latter three degraded ecosystems, the contents of soil organic C and total N were in the sequence of KNR>KGB> KMS but the difference was not significant, soil total P content in KMS (0.87 g x kg(-1)) was 2.07 and 9.67 times of that in KNR and KGB, respectively (P < 0.01), and soil microbial biomass C, N and P contents were significantly higher in KGB and KNR than in KMS (P < 0.05). The soil microbial biomass C was significantly higher in KGB than in KNR (P < 0.05), but there were no significant differences in soil microbial biomass N and P between the two ecosystems. These results illustrated that the reduction of human activity could induce a slight increase of soil organic C in Karst degraded ecosystems, and proper grazing and natural restoration could be the feasible modes for the restoration of degraded ecosystem. Soil microbial biomass was more sensitive in response to the change of ecosystem, being able to be used as a sensitive indicator to reflect the change of degraded ecosystem in Karst region. In KPF, KNR, and KGB, soil water-stable macro-aggregates (> 0.25 mm) accounted for more than 70%, and dominated by >2 mm aggregates; while in KMS, soil water-stable macro-aggregates only occupied 40.34%, and dominated by 2-0.25 mm aggregates. The destruction rate of soil structure in KMS, KGB, KNR, and KPF was 51.62%, 23.48%, 9.09%, and 9.46%, respectively (P < 0.05), indicating that human disturbance or farming practice

  6. A New Methodology for Open Pit Slope Design in Karst-Prone Ground Conditions Based on Integrated Stochastic-Limit Equilibrium Analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Ke; Cao, Ping; Ma, Guowei; Fan, Wenchen; Meng, Jingjing; Li, Kaihui

    2016-07-01

    Using the Chengmenshan Copper Mine as a case study, a new methodology for open pit slope design in karst-prone ground conditions is presented based on integrated stochastic-limit equilibrium analysis. The numerical modeling and optimization design procedure contain a collection of drill core data, karst cave stochastic model generation, SLIDE simulation and bisection method optimization. Borehole investigations are performed, and the statistical result shows that the length of the karst cave fits a negative exponential distribution model, but the length of carbonatite does not exactly follow any standard distribution. The inverse transform method and acceptance-rejection method are used to reproduce the length of the karst cave and carbonatite, respectively. A code for karst cave stochastic model generation, named KCSMG, is developed. The stability of the rock slope with the karst cave stochastic model is analyzed by combining the KCSMG code and the SLIDE program. This approach is then applied to study the effect of the karst cave on the stability of the open pit slope, and a procedure to optimize the open pit slope angle is presented.

  7. The post-Fusselman karst of the northern Franklin Mountains, west Texas and south-central New Mexico

    SciTech Connect

    Colleary, W.M. ); Crafton, J.W. Gas Research Institute, Chicago, IL ); Farraro, J.T.; LeMone, D.V. )

    1992-04-01

    The uppermost Fusselman Formation (Crazy Cat Member) at Anthony's Gap in the northern Franklin Mountains exhibits extensive karsting as documented by the presence of such features as sinkholes, breccia-filled solution channels, and preserved terra rosa. Karst control, post-El Paso as well as post-Fusselman, probably is developed by jointing resulting from recurrent fault movements in a pattern inherited from an ancestral Precambrian framework. The post-Fusselman karsting (Middle Silurian-Middle Devonian) in the Franklins developed over more than 40 m.y. The Fusselman represents the uppermost Tippecanoe sequence, and the disconformably overlying Canutillo Formation is the basal Kaskaskia in the Franklin Mountains. Overlying the Fusselman karst is a thin transgressive unit interpreted to be a silicified lag deposit. The unit has been observed to be only sporadically deposited in local swales and reaches a maximum thickness on the order of 30 cm. This dark-brown to black unit contains subrounded dolomitic pebbles of the Fusselman, as well as scattered fossil material, which in the vertebrates includes apparent teeth and bone material. This lag deposit is interpreted to represent an initial transgressive or flooding surface. This deposit has produced a significant radioactive 'hot' gamma-ray spike in a profile taken through the formation using a hand-held scintillometer. The top of the Fusselman in the Permian basin typically is marked on subsurface well logs by a 'hot' gamma-ray spike.

  8. Isotopic evolution of groundwater in a telogenetic karst aquifer: A method to study recharge and contaminant transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There exists a limited understanding of hydrogeologic flow and contaminant transport within karst aquifers, particularly in the epikarst zone, which are highly susceptible to natural and anthropogenic contamination, such as agricultural runoff, due to the interconnected nature of the surface and sub...

  9. Numerical long-term assessment of managed aquifer recharge from a reservoir into a karst aquifer in Jordan

    NASA Astrophysics Data System (ADS)

    Xanke, Julian; Jourde, Hervé; Liesch, Tanja; Goldscheider, Nico

    2016-09-01

    In semi-arid regions with high seasonal variability of water availability, adaptive management strategies and technical measures are required to ensure the sustainable use of water resources. In this study, managed recharge of storm water into a karst aquifer and the water level fluctuations related to pumping in a nearby wellfield were simulated at Wadi Wala, Jordan. We used a numerical equivalent porous medium (EPM) approach with specific adaptations to account for the heterogeneity and anisotropy of the karst aquifer. The model domain was vertically projected along the wadi course, resulting in a 2-dimensional model, and subdivided into hydraulic zones representing the karst-specific flow pattern of fast flow and slow depletion. Results show satisfying agreement of measured and simulated groundwater tables from 2002 to 2012 and predict a lowering of the average groundwater table until 2022 of around 2.7 m in the immediate surroundings of the reservoir and an increased depletion towards the wellfield, mainly caused by sedimentation in the reservoir and an associated decrease in infiltration. Abstraction at the wellfield changed considerably over the regarded time period and strongly influences the groundwater fluctuations, which shows the need of improved pumping management and monitoring. The results can serve as a basis for decision makers regarding an optimization of water management at the reservoir and wellfield. Furthermore, the presented numerical approach can be transferred to karst regions with similar physio-geographical conditions to assess managed aquifer recharge.

  10. Fate and transport of petroleum released from leaking underground-storage tanks in areas of karst topography. Technical report

    SciTech Connect

    Compton, E.

    1988-01-01

    This study determines the transport and ultimate fate of petroleum products within a region of karst geomorphology. The paper entails a complete literature review, including references that pertain to contaminant transport within karst aquifers and the remediation of hydrocarbon spills. Rapid dispersal of contaminants within cavernous karstic terrain demands prevention as the only solution, in addition to the recommended technological advances for optimal cleanup of leaking underground storage tanks. Because numerous and widespread service stations have hydrocarbon storage tanks, the contamination problem is considered a nonpoint source of pollution. Stricter standards must be imposed for regulating underground storage tanks that overly karst. Preventative measures to improve inventory control, leak detection, and upgraded tank specifications (rather than corrective actions) are necessary to protect the quality of drinking water provided by carbonate aquifers. Arkansas, louisiana, New Mexico, Oklahoma, and Texas (the five states forming U.S. EPA Region VI) constitute the designated study area. With the exception of Louisiana, each state within the region has considerably large, karst aquifers.

  11. Implementing a comprehensive approach for evaluating significance and disturbance in protected karst areas to guide management strategies.

    PubMed

    Angulo, Bárbara; Morales, Tomás; Uriarte, Jesús A; Antigüedad, Iñaki

    2013-11-30

    Many environmental studies have acquired an almost exclusively biotic perspective over the years, neglecting important key land characteristics like those of a geological and hydrological nature. This situation leads to incomplete, and even inappropriate, management strategies, particularly unjustified in the case of karst environments which form the basis of important protected areas around the world and are inherently very fragile environments compared to other natural systems. This study presents a holistic methodological approach to analyse the level of significance and disturbance in the Natural Park of Aralar (Basque Country, northern Spain) using two standardized indices: zonal Karst Significance Index (KSIZ) and zonal Karst Disturbance Index (KDIZ). The distribution of both indices in the park is based on the Geographic Information System (GIS). Thus, thematic maps regarding geological, geomorphological, biological, hydrological and cultural aspects provide the essential data for this work. The obtained results enable us to recognize the most significant and disturbed sectors of the park. These indices are subsequently combined to generate the Priority Management Index (PMI), which determine the different management needs of the territory. This comprehensive information not only serves efforts to better manage protected karst areas, but also to provide a snapshot view of the researched area to compare achieved results over time.

  12. [Effects of parent rock and land use pattern on soil fertility in Karst region of Northwest Guangxi].

    PubMed

    Yang, Shan; He, Xun-Yang; Su, Yi-Rong; Zhang, Wei; Wang, Ke-Lin

    2010-06-01

    Taking the soils developed on limestone and sandstone and with typical land use patterns in Karst region of Northwest Guangxi as test objects, this paper studied their soil fertility under effects of parent rock and land use pattern. A total of eleven soil fertility variables were selected for factor analysis, and the component score for each sampling site was assessed by using principal component analysis (PCA) sequencing and clustering diagram. The factor analysis indicated that the eleven variables could be reduced to four components, i.e., overall soil fertility, soil pH and total phosphorus, soil available phosphorus, and soil total potassium. The PCA sequencing and clustering analysis showed that the overall soil fertility was mainly affected by land use pattern, being the highest in abandoned farmland. Soil pH and total phosphorus content were mainly affected by parent rock. The pH value and total phosphorus content in the red soil developed on sandstone were much lower than those in the calcareous soil developed on limestone. Soil available phosphorus and total potassium contents were significantly affected by fertilization. The available phosphorus and total potassium contents in Karst calcareous soil and red soil were lower than the average level of China soils. Therefore, the Karst calcareous soil should be fertilized with ammonium nitrogen fertilizer to improve its phosphorus availability, while the Karst red soil should be amended with lime to increase its available phosphorus content. In addition, potassium fertilizer should be applied to the two soil types to improve their soil fertility.

  13. The challenge and future of rocky desertification control in karst areas in southwest China

    NASA Astrophysics Data System (ADS)

    Zhang, J. Y.; Dai, M. H.; Wang, L. C.; Zeng, C. F.; Su, W. C.

    2016-01-01

    Karst rocky desertification occurs after vegetation deteriorates as a result of intensive land use, which leads to severe water loss and soil erosion and exposes basement rocks, creating a rocky landscape. Karst rocky desertification is found in humid areas in southwest China, the region most seriously affected by rocky desertification in the world. In order to promote ecological restoration and help peasants out of poverty, the Chinese government carried out the first phase of a rocky desertification control project from 2006 to 2015, which initially contained the expansion of rocky desertification. Currently, the Chinese government is prepared to implement the second phase of the rocky desertification control project, and therefore it is essential to summarise the lessons learned over the last 10 years of the first phase. In this paper, we analyse the driving social and economic factors behind rocky desertification, summarise the scientific research on rocky desertification in the region, and finally identify the main problems facing rocky desertification control. In addition, we put forward several policy suggestions that take into account the perspective of local peasants, scientific research, and China's economic development and urbanisation process. These suggestions include promoting the non-agriculturalization of household livelihoods, improving ecological compensation, strengthening the evaluation of rocky desertification control and dynamic monitoring, and strengthening research on key ecological function recovery technologies and supporting technologies.

  14. Microbial communities in karst groundwater and their potential use for biomonitoring

    NASA Astrophysics Data System (ADS)

    Pronk, Michiel; Goldscheider, Nico; Zopfi, Jakob

    2009-02-01

    The structure, diversity and dynamics of microbial communities from a swallow hole draining agricultural land and two connected karst springs (Switzerland) were studied using molecular microbiological methods and related to hydrological and physicochemical parameters. Storm responses and an annual hydrological cycle were monitored to determine the short- and long-term variability, respectively, of bacterial communities. Statistical analysis of bacterial genetic fingerprints (16S rDNA PCR-DGGE) of spring water samples revealed several clusters that corresponded well with different levels of the allochthonous swallow hole contribution. Microbial communities in spring water samples highly affected by the swallow hole showed low similarities among them, reflecting the high temporal variability of the bacterial communities infiltrating at the swallow hole. Conversely, high similarities among samples with low allochthonous contribution provided evidence for a stable autochthonous endokarst microbial community. Three spring samples, representative for low, medium and high swallow hole contribution, were analysed by cloning/sequencing in order to identify the major bacterial groups in the communities. The autochthonous endokarst microbial community was mainly characterized of δ-Proteobacteria, Acidobacteria and Nitrospira species. A high percentage of unknown sequences suggested further that many karst aquifer bacteria are still undiscovered. Finally, the potential use of groundwater biomonitoring using microbial communities is discussed.

  15. [Ecological distribution and spatial niche of pheasants in the Karst mountains of southwest Guangxi Province, China].

    PubMed

    Yu, Chen-Xing; Yang, Gang; Li, Dong; Zhou, Fang

    2011-10-01

    The Karst mountain area along the Sino-Vietnam border of southwest Guangxi has been designated a "Global Biodiversity Hotspot" since 2003. We conducted a survey of pheasant species in this area, with seven species recorded, namely Chinese Francolin (Francolinus pintadeanus), Bar-backed Partridge (Arborophila brunneopectus), Mountain Bamboo Partridge (Bambusicola fytchii), Chinese Bamboo Partridge (Bambusicola thoracica), Red Junglefowl (Gallus gallus), Silver Pheasant (Lophura nycthemera) and Common Pheasant (Phasianus colchicus). Analysis and comparison of the distribution and spatial niche of these seven pheasant species revealed that Red Junglefowl had the widest spatial niche, while Chinese Francolin had the narrowest. The spatial niche overlap index was high between Chinese Francolin and the Common Pheasant, Chinese Bamboo Partridge, and Red Junglefowl. With narrow distribution range, small population, and lower ecological adaptability, it is likely that the Bar-backed Partridge is the most vulnerable pheasant species in this area. The results suggest more research and conservation measures are required for pheasant habitat protection in the Karst areas of southwest Guangxi. PMID:22006809

  16. Characterization and interaction of driving factors in karst rocky desertification: a case study from Changshun, China

    NASA Astrophysics Data System (ADS)

    Xu, E. Q.; Zhang, H. Q.

    2014-10-01

    As the most severe ecological issue in Southwest China, karst rocky desertification (KRD) has both threatened and constrained regional sustainable development. Comprehensively understanding the relationship between the evolution of KRD and relevant driving data would provide more information to combat KRD in such complex karst environments. Past studies have been limited in quantifying the relative importance of driving factors influencing fine-scale KRD evolution, and have also lacked insight into their interactive impacts. To address these issues, we have used geographical information system techniques and a geographical detector model to explore the spatial consistency of driving factors and their interactions in relation to the evolution of KRD. Changshun County in China was selected as a representative area for the study. Nine relevant driving factors, including both natural and anthropogenic factors, were studied in regard to their relationships with KRD transformation between 2000 and 2010. Our results demonstrate the relative importance of driving data in influencing the improvement and deterioration of KRD. Lithology, soil type and road influence are identified as the leading factors. Interestingly, to our study at least, there is no significant difference between the impacts of natural and anthropogenic factors. Factors were found to enhance the influence of each other for KRD transformation. In particular, the results show a non-linearly enhanced effect between driving factors, which significantly aggravates KRD. New information found in our study helps to effectively control and restore areas afflicted by KRD.

  17. Determination of the recharge area and salinization degree of karst springs in the Lamas Basin (Turkey).

    PubMed

    Yüce, Galip

    2005-12-01

    The Lamas Basin is an area covering approximately 4,400 km(2) situated on the eastern Mediterranean coast of Turkey covered with highly karstified limestone and dolomitic limestone from the Miocene and Mesozoic age, respectively. Owing to the area's low karstification basement, groundwater in the karst aquifer circulates deep from the surface towards the springs along the coast as well as to the submarine springs. This study aims working out the salinization level and recharge characteristics of the Lamas Basin using environmental isotopes techniques. In the study, the data collected previously to discover, in general terms, the groundwater characteristics within the area are reanalyzed to fulfil the purpose of the study. In conclusion, it is found that the down gradient karst springs discharging along the Mediterranean coast mostly contain groundwater contributions from higher altitudes with depleted delta(18)O and delta(2)H compositions. The delta(18)O-altitude effect was determined as approximately-0.12 per thousand/100 m which may indicate sea-spray intrusion towards inland. As a result, the salinization level of coastal springs changes ranging between 1.2 % and 17.0 %. Owing to the seawater encroachment, Ca-HCO(3) water type changes to Na-HCO(3) or Na-Cl water by the cation exchange during the dry period. As the unique freshwater potential extends along the coastal area, the groundwater production should be exploited in a way that seawater encroachment is kept at minimum.

  18. Fractured-karst spring-flow protections: a case study in Jinan, China

    NASA Astrophysics Data System (ADS)

    Qian, Jiazhong; Zhan, Hongbin; Wu, Yifeng; Li, Fulin; Wang, Jiaquan

    2006-11-01

    Jinan Springs are an important historical heritage in China and have been well known for hundreds of years. Over-abstraction of groundwater in the Jinan area has seriously endangered the hydrological system of the springs, which have stopped flowing for significant periods of time in recent years. A three-dimensional finite-element model programmed primarily at the Hefei University of Technology has been developed to simulate groundwater level change in the large fractured-karst aquifer system in the Jinan Springs field. Various spring protection plans have been explored and their effects on the water table analyzed and compared. It was found that the present rate of groundwater withdrawal from the fractured-karst system in this area was inappropriate for spring protection. The simulated results suggest that decreasing the rate of groundwater pumping from 6.9×105 to 2.7×105 m3/day is needed to protect spring flows. Additional water resource requirements in that area may be met by use of surface water and recycled waste water.

  19. Estimating recharge thresholds in tropical karst island aquifers: Barbados, Puerto Rico and Guam

    NASA Astrophysics Data System (ADS)

    Jones, Ian C.; Banner, Jay L.

    2003-07-01

    The hydrology and geochemistry of groundwater in tropical island aquifers, such as Barbados, Guam and Puerto Rico, 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. The karst aquifers on Barbados, Guam and Puerto Rico have similar rainwater and groundwater oxygen isotopic compositions. Comparison of groundwater and rainwater oxygen isotopic compositions in the three aquifers indicates that: (1) recharge occurs by rapid infiltration with little evaporation prior to recharge; and (2) recharge is associated with similar monthly rainfall thresholds of 190-200 mm. These rainfall thresholds are remarkably similar for three aquifers in different geographic locations. Differences between the spatial variations of groundwater oxygen isotopic compositions on Barbados and Puerto Rico can be attributed to the more complex groundwater flow system on Puerto Rico. The surprising similarities of hydrologic conditions under which recharge will take place can be attributed to similarities in climate and geologic conditions, such as soils and limestone bedrock, that exist on the three islands. We therefore speculate that similar recharge-rainfall thresholds may be observed in other tropical karst aquifers.

  20. Karst aquifers on small islands--the island of Olib, Croatia.

    PubMed

    Vlahović, Tatjana; Munda, Boris

    2012-10-01

    Water supply is a major problem in the Adriatic islands, especially during the summer tourism season, and represents a limiting factor to the islands' further economic development. Much attention has been given to water supply solutions, primarily in terms of attempting to use the existing island water. Unfortunately, few islands have favourable hydrological conditions to accumulate significant quantities of surface water or groundwater. In the period from 2001 to 2004, investigations were conducted on many islands to define their own freshwater or partially brackish water resources since desalinisation technology could resolve a significant part of the water supply demand on small and distant islands. Due to the specificity and complexity of research in karst areas, the study was conducted in phases and included the geological and hydrogeological reconnaissance of the island, aimed at locating possible areas on the island where the necessary quantities of groundwater of adequate quality could be captured; a detailed hydrogeological mapping of the specified areas, geophysical investigation and test drilling; and, over several days, test pumping of the most promising borehole. One of the islands investigated was the island of Olib. The conducted surveys indicated that it is possible to pump about 3.5 L/s of groundwater from the karst aquifer of the island of Olib, which fully complies with the sanitary quality of drinking water.

  1. Conservation of Terrestrial Vertebrates in a Global Hotspot of Karst Area in Southwestern China

    PubMed Central

    Luo, Zhenhua; Tang, Songhua; Jiang, Zhigang; Chen, Jing; Fang, Hongxia; Li, Chunwang

    2016-01-01

    The karst area of southwest China (KASC) is the largest piece of karst landscape on the earth and a global biodiversity hot-spot with high concentrations of endemic species. Although a number of nature reserves (NRs) have been established across the region, the representativeness of biodiversity of the NR system is still unknown. Based on comprehensive literature and field surveys, and intensive consultations with zoologists and wildlife managers, we compiled distributions of 1,204 terrestrial vertebrate species and 271 NRs in KASC. We found Jinxiu, Mengla, Hekou, and Jinghong have the richest amphibian species; Jinxiu has the highest species richness of reptiles; Jinghong, Menghai, and Mengla have the largest numbers of avian species; whereas, Mengla, Longzhou, and Ningming have the greatest mammalian diversity in the region. Gap analysis among NR system, species richness pattern, and five biogeographic indicators found insufficient representation of the NR system on territorial vertebrate diversity. The conservation effectiveness in Guizhou Province was much lower than that in Guangxi and Yunnan Provinces. Under-representation and over-representation simultaneously occurred in many of the ecoregions, elevation classes, vegetation types, landcover categories, and human disturbance intensity gradients. For conservation of terrestrial vertebrates in KASC, several suggestions were presented in this study. PMID:27228463

  2. Analysis of methods to estimate spring flows in a karst aquifer

    USGS Publications Warehouse

    Sepulveda, N.

    2009-01-01

    Hydraulically and statistically based methods were analyzed to identify the most reliable method to predict spring flows in a karst aquifer. Measured water levels at nearby observation wells, measured spring pool altitudes, and the distance between observation wells and the spring pool were the parameters used to match measured spring flows. Measured spring flows at six Upper Floridan aquifer springs in central Florida were used to assess the reliability of these methods to predict spring flows. Hydraulically based methods involved the application of the Theis, Hantush-Jacob, and Darcy-Weisbach equations, whereas the statistically based methods were the multiple linear regressions and the technology of artificial neural networks (ANNs). Root mean square errors between measured and predicted spring flows using the Darcy-Weisbach method ranged between 5% and 15% of the measured flows, lower than the 7% to 27% range for the Theis or Hantush-Jacob methods. Flows at all springs were estimated to be turbulent based on the Reynolds number derived from the Darcy-Weisbach equation for conduit flow. The multiple linear regression and the Darcy-Weisbach methods had similar spring flow prediction capabilities. The ANNs provided the lowest residuals between measured and predicted spring flows, ranging from 1.6% to 5.3% of the measured flows. The model prediction efficiency criteria also indicated that the ANNs were the most accurate method predicting spring flows in a karst aquifer. ?? 2008 National Ground Water Association.

  3. Solute transport modelling in karst conduits with slow zones during different hydrologic conditions

    NASA Astrophysics Data System (ADS)

    Morales, Tomás; Uriarte, Jesus A.; Olazar, Martín; Antigüedad, Iñaki; Angulo, Bárbara

    2010-09-01

    SummaryEight tracer tests conducted under different flow conditions in two well-developed karst connections in the Santa Eufemia-Ereñozar karst unit (Basque Country, northern Spain) are considered for transport characterization. Lithium tracer was injected as an impulse release for obtaining well-defined tracer breakthrough curves (TBCs). In order to simulate curve evolution and obtain transport characteristic parameters, two approaches have been applied: a standard analytical solution and a new numerical one that accounts for transient storage processes. The numerical model simulates the effect of localized variations in conduit geometry that give way to dead zones or slow zones in the transport process. This model fits the experimental curves well and explains their tails mainly by diversion processes from the main flow line towards stagnant zones. An increase in dispersion coefficient values is observed in both conduits as flow rates and average flow velocities increase. Stagnation and tracer transient retention processes, which may be quantified by means of the numerical solution, are more important as circulating flow rates decrease and travel times increase. The diversion processes in the two connections follow a similar evolution, with significant changes in the magnitude of the retentions registered depending on the hydrodynamic state of the traced system. Consequently, there is a clear hydrodynamic-controlled tailing effect.

  4. Impacts of karst paleo-sinkholes on mining and environment in northern China

    NASA Astrophysics Data System (ADS)

    Yin, Shang-Xian; Zhang, Jincai

    2005-10-01

    The karst paleo-sinkhole is a special geological structure widely found in the coal measures of northern China. Some paleo-sinkholes have high permeability and connectivity, making them excellent connectors between the karst aquifer and the coal seam. Consequently, during coal extraction disastrous water inrushes take place frequently, which cause severe loss not only in mine submersions and personnel casualties, but also in environmental quality. Locations and the geological and hydrogeological characteristics of paleo-sinkholes in northern China are presented. In-situ drilling and excavation results show that paleo-sinkholes have different hydrogeological behaviors in different regions and in different mines. Based on observed data, mining-induced strata failure in the seam floor is analyzed. The existence of paleo-sinkholes increases the floor strata failure zone. Numerical simulation then is adopted to model coal mining with the effects of both the paleo-sinkholes and the water pressure in the confined aquifer. Analyses of the simulation conclude that the paleo-sinkhole induces the increase in the strata failure and deformation. These make water inrushes more likely to happen.

  5. A semi-automatic model for sinkhole identification in a karst area of Zhijin County, China

    NASA Astrophysics Data System (ADS)

    Chen, Hao; Oguchi, Takashi; Wu, Pan

    2015-12-01

    The objective of this study is to investigate the use of DEMs derived from ASTER and SRTM remote sensing images and topographic maps to detect and quantify natural sinkholes in a karst area in Zhijin county, southwest China. Two methodologies were implemented. The first is a semi-automatic approach which stepwise identifies the depression using DEMs: 1) DEM acquisition; 2) sink fill; 3) sink depth calculation using the difference between the original and sinkfree DEMs; and 4) elimination of the spurious sinkholes by the threshold values of morphometric parameters including TPI (topographic position index), geology, and land use. The second is the traditional visual interpretation of depressions based on the integrated analysis of the high-resolution aerial photographs and topographic maps. The threshold values of the depression area, shape, depth and TPI appropriate for distinguishing true depressions were abstained from the maximum overall accuracy generated by the comparison between the depression maps produced by the semi-automatic model or visual interpretation. The result shows that the best performance of the semi-automatic model for meso-scale karst depression delineation was using the DEM from the topographic maps with the thresholds area >~ 60 m2, ellipticity >~ 0.2 and TPI <= 0. With these realistic thresholds, the accuracy of the semi-automatic model ranges from 0.78 to 0.95 for DEM resolutions from 3 to 75 m.

  6. [Effects of different land use types on soil nutrients in karst region of Northwest Guangxi].

    PubMed

    Xu, Lian-Fang; Wang, Ke-Lin; Zhu, Han-Hua; Hou, Ya; Zhang, Wei

    2008-05-01

    Selecting the main land use types (shrub land, secondary forest land, orchard, pasture land, and upland) at the peak-cluster depression in karst region of Northwest Guangxi as test objects, this paper studied the effects of different land use types on soil nutrients. The results showed that, the contents of soil organic matter (SOM), total N, and available N were 86%-155%, 62% -119%, and 66%-215% higher in shrub land and secondary forest land than in orchard, pasture land, and upland, respectively, i. e., increased with the decrease of land use intensity. The contents of soil total P and K were mainly controlled by their origins, but less affected by land use type. Soil available P content was mainly affected by fertilization, while soil available K content was controlled by vegetation cover and water- and soil loss. Land use type was the dominant factor affecting the contents of soil SOM, total N, and available N, P and K. Extensive cultivation could decrease soil nutrient contents and lead to the degradation of cropland soil, while ecological restoration could improve soil fertility. Therefore, in karst region, the measures as changing extensive cultivation into intensive farming, applying organic fertilizers, balance fertilization, and "Grain for Green Project" for > or = 25 degrees slope should be taken to recover and rebuild the eco-environment, and keep the sustainable utilization of land resources.

  7. Mass effects meet species sorting: transformations of microbial assemblages in epiphreatic subsurface karst water pools.

    PubMed

    Shabarova, Tanja; Widmer, Franco; Pernthaler, Jakob

    2013-09-01

    We investigated the transformations of the microbial communities in epiphreatic karst cave pools with different flooding frequencies. Fingerprinting of 16S rRNA genes was combined with microscopic and sequence analysis to examine if source water would transport comparable microbial inocula into the pools at consecutive flood events, and to assess possible effects of residence time on the microbial assemblages during stagnant periods. Variability in the concentrations of dissolved organic carbon and conductivity indicated differences between floods and changes of pool water over time. High numbers of Betaproteobacteria affiliated with Methylophilaceae and Comamonadaceae were introduced into the pools during floodings. While the former persisted in the pools, the latter exhibited considerable microdiversification. These Betaproteobacteria might thus represent core microbial groups in karst water. A decrease in the estimated total diversity of the remaining bacterial taxa was apparent after a few weeks of residence: Some were favoured by stagnant conditions, whereas the majority was rapidly outcompeted. Thus, the microbial communities consisted of different components governed by complementary assembly mechanisms (dispersal versus environmental filtering) upon introduction into the pools. High overlap of temporary and persistent community members between samplings from two winters, moreover, reflected the seasonal recurrence of the studied microbial assemblages.

  8. Strategy for definition and protection of east Tennessee karst groundwater basins

    SciTech Connect

    Rubin, P.A.; Lemiszki, P.J.; Poling, R.S.

    1992-12-31

    This paper describes and gives suggestions for protecting the bedrock geology of eastern Tennessee which is typical of the southern Appalachian Valley and Ridge province. Carbonate beds (limestones and dolomites) of the Knox and Chickamauga Groups are bounded by non-carbonate beds, most of which strike northeast and dip steeply (10{degrees}--45{degrees}) to the southeast. The carbonate aquifers are maturely karstified and are extremely vulnerable to contaminant infiltration, thus necessitating appropriate land use planning focused on their environmental sensitivity. Urban expansion is resulting in greater land development in karst regions. Planned and existing activities produce wastes that may potentially leach into underlying karst systems. This waste may flow rapidly and untreated for many miles along strike. The potential degradation of aquifers and receiving streams due to the cumulative waste loading of numerous small enterprises may be more environmentally destructive than a few hazardous waste sites. Costs to remediate contaminated water supplies and streams can be in the millions of dollars versus the substantially lower costs of prudent land use planning.

  9. Automated delineation of karst sinkholes from LiDAR-derived digital elevation models

    NASA Astrophysics Data System (ADS)

    Wu, Qiusheng; Deng, Chengbin; Chen, Zuoqi

    2016-08-01

    Sinkhole mapping is critical for understanding hydrological processes and mitigating geological hazards in karst landscapes. Current methods for identifying sinkholes are primarily based on visual interpretation of low-resolution topographic maps and aerial photographs with subsequent field verification, which is labor-intensive and time-consuming. The increasing availability of high-resolution LiDAR-derived digital elevation data allows for an entirely new level of detailed delineation and analyses of small-scale geomorphologic features and landscape structures at fine scales. In this paper, we present a localized contour tree method for automated extraction of sinkholes in karst landscapes. One significant advantage of our automated approach for sinkhole extraction is that it may reduce inconsistencies and alleviate repeatability concerns associated with visual interpretation methods. In addition, the proposed method has contributed to improving the sinkhole inventory in several ways: (1) detection of non-inventoried sinkholes; (2) identification of previously inventoried sinkholes that have been filled; (3) delineation of sinkhole boundaries; and (4) characterization of sinkhole morphometric properties. We applied the method to Fillmore County in southeastern Minnesota, USA, and identified three times as many sinkholes as the existing database for the same area. The results suggest that previous visual interpretation method might significantly underestimate the number of potential sinkholes in the region. Our method holds great potential for creating and updating sinkhole inventory databases at a regional scale in a timely manner.

  10. Flow dynamics and erosion rate of representative karst basin (Upper Aniene River, Central Italy)

    SciTech Connect

    Bono, P.; Percopo, C.

    1996-04-01

    Experimental data refer to a preliminary estimate of suspended solid and solute load of a perennial river. The basin is composed almost entirely of bare mesozoic, highly fractured, karstified carbonate rocks of the central Apennine range. The suspended solid load related to stormflow events in 1991 corresponds to about 14,970 t yr{sup -1}. For the same period the solute load is 60,060 t yr{sup -1} for a mean base flow discharge of 9.4 m{sup 3} s{sup -1}. Based on the mean concentration of Ca + Mg in water, the value of dissolution of carbonate rocks of 37.1 m{sup 3} km{sup -2} (equivalent approximately to 0.04 mm yr{sup -1}) was calculated. Physical and chemical variations that occur during storm events indicate the complex dynamic processes in the karst aquifier and the role undertaken by the epikarst as perched water reservoir and by the major conduits that develop through the vadose and saturated zones of the karst system. 12 refs., 10 figs., 5 tabs.

  11. Adaptive and nonadaptive genome size evolution in Karst endemic flora of China.

    PubMed

    Kang, Ming; Tao, Junjie; Wang, Jing; Ren, Chen; Qi, Qingwen; Xiang, Qiu-Yun; Huang, Hongwen

    2014-06-01

    Genome size variation is of fundamental biological importance and has been a longstanding puzzle in evolutionary biology. Several hypotheses for genome size evolution including neutral, maladaptive, and adaptive models have been proposed, but the relative importance of these models remains controversial. Primulina is a genus that is highly diversified in the Karst region of southern China, where genome size variation and the underlying evolutionary mechanisms are poorly understood. We reconstructed the phylogeny of Primulina using DNA sequences for 104 species and determined the genome sizes of 101 species. We examined the phylogenetic signal in genome size variation, and tested the fit to different evolutionary models and for correlations with variation in latitude and specific leaf area (SLA). The results showed that genome size, SLA and latitudinal variation all displayed strong phylogenetic signals, but were best explained by different evolutionary models. Furthermore, significant positive relationships were detected between genome size and SLA and between genome size and latitude. Our study is the first to investigate genome size evolution on such a comprehensive scale and in the Karst region flora. We conclude that genome size in Primulina is phylogenetically conserved but its variation among species is a combined outcome of both neutral and adaptive evolution.

  12. Strategy for definition and protection of east Tennessee karst groundwater basins

    SciTech Connect

    Rubin, P.A.; Lemiszki, P.J. ); Poling, R.S. )

    1992-01-01

    This paper describes and gives suggestions for protecting the bedrock geology of eastern Tennessee which is typical of the southern Appalachian Valley and Ridge province. Carbonate beds (limestones and dolomites) of the Knox and Chickamauga Groups are bounded by non-carbonate beds, most of which strike northeast and dip steeply (10[degrees]--45[degrees]) to the southeast. The carbonate aquifers are maturely karstified and are extremely vulnerable to contaminant infiltration, thus necessitating appropriate land use planning focused on their environmental sensitivity. Urban expansion is resulting in greater land development in karst regions. Planned and existing activities produce wastes that may potentially leach into underlying karst systems. This waste may flow rapidly and untreated for many miles along strike. The potential degradation of aquifers and receiving streams due to the cumulative waste loading of numerous small enterprises may be more environmentally destructive than a few hazardous waste sites. Costs to remediate contaminated water supplies and streams can be in the millions of dollars versus the substantially lower costs of prudent land use planning.

  13. Karst-related diagenesis and reservoir development in the Arbuckle Group, Wilburton field, Oklahoma

    SciTech Connect

    Bliefnick, D.M. ); Belfield, W.C. )

    1992-04-01

    Wilburton field is a multizone reservoir on the southwestern edge of the Arkoma basin. The most recent zone to be declared commercial is the Cambrian-Ordovician Arbuckle Group. Faults, structural position, depositional environment, and diagenetic alterations play a role in controlling reservoir quality, communication of fluids and pressures within the reservoir, and stratigraphic correlations. The Arbuckle Group in Wilburton field consists of dolomite, calcareous dolomite and minor clastic-rich intervals