Numerous quantitative relationships have been formulated to describe the nature of surface-drainage networks. These parameters have been used in various studies of geomorphology and surface-water hydrology, such as flood characteristics, sediment yield, and evolution of basin morphology. Little progress has been made in applying these quantitative descriptors to karst flow systems due to the lack of sufficiently complete data and inadequate technology for processing the large, complex data sets. However, as a result of four decades of investigation, an abundance of data now exists for the Mammoth Cave Watershed providing the opportunity for broader quantitative research in the organization of a large, highly-developed, karst-drainage network. Developing Geographic Information System (GIS) technology has provided tools to 1) book-keep the karst system's large, complex spatial data sets, 2) analyze and quantitatively model karst processes, and 3) visualize spatially and temporally complex data. []Karst aquifers display drainage characteristics that in many ways appear similar to surface networks. The purpose of my research was to explore techniques by which quantitative methods of drainage-network analysis can be applied to the organization and flow patterns in the Turnhole Bend Groundwater Basin of the Mammoth Cave Watershed. []Morphometric analysis of mapped active base-flow, stream-drainage density within the Turnhole Bend Groundwater Basin resulted in values ranging from 0.24 km/km2 to 1.13 km/km2. A nearby, climatologically similar, nonkarst surface drainage system yielded a drainage density value of 1.36 km/km2. Since the mapped cave streams necessarily represent only a fraction of the total of underground streams within the study area, the actual subsurface values are likely to be much higher. A potential upper limit on perennial drainage density for the Turnhole Bend Groundwater Basin was calculated by making the assumption that each sinkhole drains at least one first-order stream. Using Anhert and Williams’ (1998) average of 74 sinkholes per km2 for the Turnhole Bend Groundwater Basin, the minimum flow-length draining one km2 is 6.25-7.22 km (stated as drainage density, 6.25-7.22 km/km2). []Stream ordering of cave streams and their catchments generally follow Hortonian relationships observed for surface-stream networks. Subsurface streams within the Mammoth Cave Watershed generally exhibit a converging, dendritic pattern and possess drainage basins proportionately large for their order. However, even at base-flow conditions, the Turnhole Bend drainage system continues to possess confounding characteristics. These include at least one leakage to an adjacent groundwater basin (Meiman et al., 2001), diverging streams sharing the same surface catchment (Glennon and Groves, 1997), and highly complex, three-dimensional basin boundaries (Meiman et al., 2001). In spite of the incomplete data set available for the Mammoth Cave Watershed, study of initial values suggests an orderly subsurface flow network with numerical results that allow for comparison of the karst-flow network to surface fluvial systems.

Discrepancies in simulated transmissivities of the Upper Floridan aquifer were identified in the overlap areas of seven ground-water flow models in southwest and west-central Florida. Discrepancies in transmissivity are generally the result of uncertainty and spatial variability in other aquifer properties. All ground-water flow models were used to simulate the potentiometric surface of the Upper Floridan aquifer for approximated steady-state conditions from August 1993 through July 1994 using the time-independent hydraulic properties assigned to the models. Specifiedhead and general-head boundary data used to generate boundary conditions appropriate to these models were obtained from the estimated annual average heads for the steady-state period. Water-use data and the approximated surficial aquifer system water table were updated to reflect conditions during the approximated steady-state period. Simulated heads at control points, vertical leakage rates to the Upper Floridan aquifer, and spring flows were used to analyze the discrepancies in transmissivities in model overlap areas. Factors causing transmissivity discrepancies in model overlap areas include differences among directly applied recharge rates, differences among model simulated vertical leakance values assigned to the overlaying confining unit resulting in varying leakage rates to the Upper Floridan aquifer, differences in heads and conductances used in general-head boundary cells, and differences in transmissivities assigned in the vicinity of springs. Additional factors include the grid resolution and algorithm used to approximate the heads of the surficial aquifer system when these are used as a source/sink layer. 

Conference Proceedings

Sinkholes and the Engineering and Environmental Impacts of Karst Contains over 70 papers addressing karst topography which impacts water resources, waste disposal, foundation stability, and a multitude of other geotechnical and environmental issues. These papers were presented at the 10th Multidisciplinary Conference held September 24-28, 2005 in San Antonio, Texas and Sponsored by the Geo-Institute of ASCE, P. E. LaMoreaux & Associates, Inc. and Edwards Aquifer Authority. The goal of this conference was to share knowledge and experience among disciplines by emphasizing practical applications and case studies. This proceedings will benefit environmental and geotechnical engineers, and others involved in water resources, water disposal, and foundation stability issues.

Contents:

 Application of Geophysical Logging Techniques for Multi-Channel Well Design and Installation in a Karst Aquifer (by Frank Bogle, ...)

 Case Studies of Massive Flow Conduits in Karst Limestone (by Jim L. Lolcama)
 
 A Case Study of the Samanalawewa Reservoir on the Walawe River in an Area of Karst in Sri Lanka (by K. Laksiri, ...)

 Characterization and Water Balance of Internal Drainage Sinkholes (by Nico M. Hauwert, ...) 

 Characterization of Desert Karst Terrain in Kuwait and the Eastern Coastline of the Arabian Penninsula (by Waleed Abdullah, ...)

 Characterization of a Sinkhole Prone Retention Pond Using Multiple Geophysical Surveys and Closely Spaced Borings (by Nick Hudyma, ...)
 
 Combining Surface and Downhole Geophysical Methods to Identify Karst Conditions in North-Central Iowa (by J. E. Wedekind, ...)

 Complexities of Flood Mapping in a Sinkhole Area (by C. Warren Campbell, P.E.)
 
 Conceptualization and Simulation of the Edwards Aquifer, San Antonio Region, Texas (by R. J. Lindgren, ...)

 Database Development and GIS Modeling to Develop a Karst Vulnerability Rating for I-66, Somerset to London, KY (by Michael A. Krokonko, ...)

 Design and Construction of the Foundations for the Watauga Raw Water Intake Facility in Karstic Limestone near the City of Johnson City, TN (by Tony D. Canale, P.E., ...)

 Detection of Three-Dimensional Voids in Karstic Ground (by Derek V. Morris, P.E., ...)

 Development and Evolution of Epikarst in Mid-Continent US Carbonates (by Tony L. Cooley, P.E.)

 Dye Tracing Sewage Lagoon Discharge in a Sandstone Karst, Askov, Minnesota (by Emmit Calvin Alexander, Jr., ...)

 The Effectiveness of GPR in Sinkhole Investigations (by E. D. Zisman, P.E., ...)

 Effects of Anthropogenic Modification of Karst Soil Texture on the Water Balance of ?Alta Murgia? (Apulia, Italy) (by F. Canora, ...)

 Environmental Isotope Study on Recharge and Groundwater Residence Time in a covered Ordovician Carbonate Rock (by Zhiyuan Ma, ...)

 Error and Technique in Fluorescent dye Tracing (by Chris Smart)
 
 Essential Elements of Estimating Engineering Properties of Karst for Foundation Design (by Ramanuja Chari Kannan, P.E., Fellow, ASCE)

 Estimating Grout Quantities for Residential Repairs in Central Florida Karst (by Larry D. Madrid, P.E., ...)

 Evaluation of Groundwater Residence Time in a Karstic Aquifer Using Environmental Tracers: Roswell Artesian Basin, New Mexico (by Lewis Land)

 Experience of Regional Karst Hazard and Risk Assessment in Russia (by A. L. Ragozin, ...)

 Experimental Study of Physical Models for Sinkhole Collapses in Wuhan, China (by Mingtang Lei, ...)

 Fractal Scaling of Secondary Porosity in Karstic Exposures of the Edwards Aquifer (by Robert E. Mace, ...)

 The Geological Characteristics of Buried Karst and Its Impact on Foundations in Hong Kong, China (by Steve H. M. Chan, ...)

 Geophysical Identification of Evaporite Dissolution Structures Beneath a Highway Alignment (by M. L. Rucker, ...)

 Geotechnical Analysis in Karst: The Interaction between Engineers and Hydrogeologists (by R. C. Bachus, P.E.)

 The Gray Fossil Site: A Spectacular Example in Tennessee of Ancient Regolith Occurrences in Carbonate Terranes, Valley and Ridge Subpovince, South Appalachians U.S.A. (by G. Michael Clark, ...)

 Ground-Water Basin Catchment Delineation by Bye Tracing, Water Table Mapping, Cave Mapping, and Geophysical Techniques: Bowling Green Kentucky (by Nicholas C. Crawford)

 Groundwater Flow in the Edwards Aquifer: Comparison of Groundwater Modeling and Dye Trace Results (by Brian A. Smith, ...)

 Grouting Program to Stop Water Flow through Karstic Limestone: A Major Case History (by D. M. Maciolek)

 Highway Widening in Karst (by M. Zia Islam, P.E., ...)

 How Karst Features Affect Recharge? Implication for Estimating Recharge to the Edwards Aquifer (by Yun Huang, ...)

 Hydrogeologic Investigation of Leakage through Sinkholes in the Bed of Lake Seminole to Springs Located Downstream from Jim Woodruff Dam (by Nicholas C. Crawford, ...)

 The Hydrologic Function of the soil and Bedrock System at Upland Sinkholes in the Edwards Aquifer Recharge Zone of South-Central Texas (by A. L. Lindley)

 An Integrated Geophysical Approach for a Karst Characterization of the Marshall Space Flight Center (by Lynn Yuhr, ...)

 Integrated Geophysical Surveys Applied to Karstic Studies Over Transmission Lines in San Antonio, Texas (by Mustafa Saribudak, ...)

 Judge Dillon and Karst: Limitations on Local Regulation of Karst Hazards (by Jesse J. Richardson, Jr.)

 Karst Groundwater Resource and Advantages of its Utilization in the Shaanbei Energy Base in Shaanxi Province, China (by Yaoguo Wu, ...)

 Karst Hydrogeology and the Nature of Reality Revisited: Philosophical Musings of a Less Frustrated Curmudgeon (by Emmit Calvin Alexander, Jr.)

 Karst in Appalachia ? A Tangled Zone: Projects with Cave-Sized Voids and Sinkholes (by Clay Griffin, ...)

 Karstic Features of Gachsaran Evaporites in the Region of Ramhormoz, Khuzestan Province, in Southwest Iran (by Arash Barjasteh)

 Large Perennial Springs of Kentucky: Their Identification, Base Flow, Catchment, and Classification (by Joseph A. Ray, ...)

 Large Plot Tracing of Subsurface Flow in the Edwards Aquifer Epikarst (by P. I. Taucer, ...)
 Lithology as a Predictive Tool of Conduit Morphology and Hydrology in Environmental Impact Assessments (by George Veni)

 Metadata Development for a Multi-State Karst Feature Database (by Yongli Gao, ...)

 Micropiling in Karstic Rock: New CMFF Foundation Solution Applied at the Sanita Factory (by Marc Ballouz)

 Modeling Barton Springs Segment of the Edwards Aquifer Using MODFLOW-DCM (by Alexander Y. Sun, ...)

 Multi-Level Monitoring Well Completion Technologies and Their Applicability in Karst Dolomite (by Todd Kafka, ...)

 National-Scale Risk Assessment of sinkhole Hazard in China (by Xiaozhen Jiang, ...)

 New Applications of Differential Electrical Resistivity Tomography and Time Domain Reflectometry to Modeling Infiltration and Soil Moisture in Agricultural Sinkholes (by B. F. Schwartz, ...)

 Non-Regulatory Approaches to Development on Karst (by Jesse J. Richardson, Jr., ...)

 PA State Route 33 Over Bushkill Creek: Structure Failure and Replacement in an Active Sinkhole Environment (by Kerry W. Petrasic, P.E.)

 Quantifying Recharge via Fractures in an Ashe Juniper Dominated Karst Landscape (by Lucas Gregory, ...)

 Quantitative Groundwater Tracing and Effective Numerical Modeling in Karst: An Example from the Woodville Karst Plain of North Florida (by Todd R. Kincaid, ...)

 Radial Groundwater Flow at Landfills in Karst (by J. E. Smith)
 
 Residual Potential Mapping of Contaminant Transport Pathways in Karst Formations of Southern Texas (by D. Glaser, ...)

 Resolving Sinkhole Issues: A State Government Perspective (by Sharon A. Hill)

 Shallow Groundwater and DNAPL Movement within Slightly Dipping Limestone, Southwestern Kentucky (by Ralph O. Ewers, ...)

 Sinkhole Case Study ? Is it or Isn?t it a Sinkhole? (by E. D. Zisman, P.E.)

 Sinkhole Occurrence and Changes in Stream Morphology: An Example from the Lehigh Valley Pennsylvania (by William E. Kochanov)

 Site Characterization and Geotechnical Roadway Design over Karst: Interstate 70, Frederick County, Maryland (by Walter G. Kutschke, P.E., ...)

 Soil Stabilization of the Valley Creek Trunk Sewer Relief Tunnel (by Jeffrey J. Bean, P.E., ...)

 Some New Approaches to Assessment of Collapse Risks in Covered Karsts (by Vladimir Tolmachev, ...)

 Spectral Deconvolution and Quantification of Natural Organic Material and Fluorescent Tracer Dyes (by Scott C. Alexander)

 Springshed Mapping in Support of Watershed Management (by Jeffrey A. Green, ...) 

 Sustainable Utilization of Karst Groundwater in Feicheng Basin, Shandong Province, China (by Yunfeng Li, ...)
 
 Transport of Colloidal and Solute Tracers in Three Different Types of Alpine Karst Aquifers ? Examples from Southern Germany and Slovenia (by N. Göppert, ...)

 Use of the Cone Penetration Test for Geotechnical Site Characterization in Clay-Mantled Karst (by T. C. Siegel, ...)

 The Utility of Synthetic Aperture Radar (SAR) Interferometry in Monitoring Sinkhole Subsidence: Subsidence of the Devil?s Throat Sinkhole Area (Nevada, USA) (by Rana A. Al-Fares)

 Void Evolution in Soluble Rocks Beneath Dams Under Limited Flow Condition (by Emmanuel S. Pepprah, ...)

 This paper presents the basic elements of a conceptual model for the development of epikarst in US mid-continent, horizontally-bedded carbonates in which flow is largely confined to secondary and tertiary porosity. The model considers the development of epikarst regimes in carbonate sequences beginning shortly after non-carbonate rocks are eroded away to expose the underlying carbonates and follows this through capture of the shallow flow by deeper dissolution conduits with reorientation of the epikarst to a more vertical form. The model does not require an underlying zone of vadose flow and in many cases considers development of such a zone to depend on the water supply provided by prior development of the epikarst. It is not claimed that all epikarsts form in the accordance with this model; rather this paper presents a viable additional model for epikarst formation under appropriate starting conditions. Factors influencing the development of epikarst are a combination of: 1) the pre-karst topography and modifications to this as the system evolves, 2) the original distribution and aperture of fractures as well as the distance and orientation of physically favorable fractures relative to potential discharge points, such as existing dissolutionally-enhanced channels with low head or nearby valleys, 3) character of soil cover as this affects percolation of water to the rock, erodability of the soil, sediment filling of conduits, and transport of sediment 4) variations in availability of dissolutionally aggressive water with time and location, and 5) low solubility layers, such as shale or chert, that promote lateral flow until a penetration point can be found. These interact to form an epikarst and deeper karst system that progressively increases its capacity both by internal improvement of its flow routes and extension into adjacent areas. The availability of water needed to promote dissolution also often has a positive feedback relationship to epikarst, in which locations of most active dissolution modify their vicinity to progressively increase capture of water, which promotes further dissolution. In early stages, lateral flow through the overlying soils and along top-of-rock must dominate the groundwater flow because the relatively intact carbonates have insufficient transmissivity to convey the available recharge through the body of the rock. Top-of-rock runnels developed by a combination of dissolution of their floors and piping erosion of their roofs would carry a significant portion of the flow. Horizontally-oriented epikarst develops with discharge to local drainage. Cutters and pinnacles, collapse-related macropores, and areas of concentrated recharge would begin to form at this stage. Initial downward propagation of this system would occur mostly due to lateral flow. Mixing corrosion could occur in sumps in these lateral flow routes when fresh, percolating rainwater mixes with older water with a higher dissolved load. Should conditions be suitable, leakage from this system promotes the migration of deeper karst conduits into the area by Ewers multi-tiered headward linking. Other sources of water may also bring in such deeper conduits. Once such deeper conduits are present, the epikarst can evolve into a more vertically oriented system, at least in the vicinity of master drains into this deeper system. Former shallow epikarst routes may then plug with sediment. In some areas, deeper systems may never develop due to unfavorable conditions. The epikarst may be the only significant system in these cases. This includes the case of poor karst formers such as interbedded shales and carbonates that may have very shallow horizontal epikarst flow paths that channel shallow subsurface flows.