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Articles 13561 - 13590 of 16717

Full-Text Articles in Physical Sciences and Mathematics

Legacy Data In The Minnesota Spring Inventory, Greg Brick Oct 2015

Legacy Data In The Minnesota Spring Inventory, Greg Brick

Sinkhole Conference 2015

Past spring inventories have covered certain parts of Minnesota reasonably well, notably, the springs of the Minneapolis-St. Paul metropolitan area and the southeastern Minnesota karst. But hitherto, there has not been a systematic effort to create a uniform statewide inventory. The first step, before hunting down new springs, was to compile existing data and the most fruitful source of hydrological legacy data for the Minnesota spring inventory was the DNR Fisheries files. Once entered into a GIS-capable database, these spring locations can help “seed the ground” so that when crews finally do take to the field to map more springs, …

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History And Future Of The Minnesota Karst Feature Database, Robert Tipping, Mathew Rantala, E. Calvin Alexander Jr., Yongli Gao, Jeffrey Green Oct 2015

History And Future Of The Minnesota Karst Feature Database, Robert Tipping, Mathew Rantala, E. Calvin Alexander Jr., Yongli Gao, Jeffrey Green

Sinkhole Conference 2015

Since the 1990s, the University of Minnesota and the Minnesota Department of Natural Resources have maintained a karst features database that is used to conduct research on karst processes and inventory karst features. Originally designed as a tabular database only, the karst features database developed into a spatial database in 2002, with tabular data stored in Microsoft Access and a spatial component managed in ESRI ArcView. In 2012, the database was converted to a single, relational database platform, PostgreSQL, with both tabular and spatial components edited in ESRI ArcMap. Custom editing forms are written in Visual Basic and are accessed …

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A Semi-Automated Tool For Reducing The Creation Of False Closed Depressions From A Filled Lidar-Derived Digital Elevation Model, John Wall, Daniel H. Doctor, Silvia Terziotti Oct 2015

A Semi-Automated Tool For Reducing The Creation Of False Closed Depressions From A Filled Lidar-Derived Digital Elevation Model, John Wall, Daniel H. Doctor, Silvia Terziotti

Sinkhole Conference 2015

Closed depressions on the land surface can be identified by ‘filling’ a digital elevation model (DEM) and subtracting the filled model from the original DEM. However, automated methods suffer from artificial ‘dams’ where surface streams cross under bridges and through culverts. Removal of these false depressions from an elevation model is difficult due to the lack of bridge and culvert inventories; thus, another method is needed to breach these artificial dams. Here, we present a semi-automated workflow and toolbox to remove falsely detected closed depressions created by artificial dams in a DEM. The approach finds the intersections between transportation routes …

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Sinkhole Vulnerability Mapping: Results From A Pilot Study In North Central Florida, Clint Kromhout, Alan E. Baker Oct 2015

Sinkhole Vulnerability Mapping: Results From A Pilot Study In North Central Florida, Clint Kromhout, Alan E. Baker

Sinkhole Conference 2015

At the end of June in 2012, Tropical Storm Debby dropped a record amount of rainfall across Florida which triggered hundreds, if not thousands, of sinkholes to form which resulted in tremendous damage to property. The Florida Division of Emergency Management contracted with the Florida Department of Environmental Protection’s Florida Geological Survey to produce a map depicting the state’s vulnerability to sinkhole formation. The three-year project began with a pilot study in three northern Florida counties: Columbia, Hamilton and Suwannee. Utilizing the statistical modeling method Weights of Evidence, results from the pilot study yielded a 93 percent success rate of …

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Shallow Depressions In The Florida Coastal Plain: Karst And Pseudokarst, Sam B. Upchurch, Thomas M. Scott, Michael C. Alfieri, Thomas L. Dobecki Oct 2015

Shallow Depressions In The Florida Coastal Plain: Karst And Pseudokarst, Sam B. Upchurch, Thomas M. Scott, Michael C. Alfieri, Thomas L. Dobecki

Sinkhole Conference 2015

In Florida, shallow depressions (i.e., depressions <1-2 m in depth) on the land surface are often attributed to sinkhole development. However, it has become evident that there are at least six different mechanisms through which these depressions can form in geologically young cover sediments. These mechanisms include: 1. Cover-subsidence sinkholes over shallow limestone; 2. Suffosion sinkholes over shallow limestone; 3. Cover settlement over shallow shell beds; 4. Large, aeolian deflation areas that resemble “Carolina bays;” 5. Depressions that mimic landforms developed on a shallow paleosol; and 6. Depressions created by pedodiagenesis (i.e., conversion of smectite to kaolinite) in a soil-forming environment. Of these, only the first two appear to represent traditional mechanisms for sinkhole development in eogenetic karst. Cover settlement over shell beds is poorly understood and incorrectly attributed to sinkhole development processes. This type of depression has serious limitations in terms of cover thickness and shell content of the substrate. The last three mechanisms are pseudokarst created by aeolian and soil-forming processes. In this paper we present examples of each and discuss their constraints and evidence.

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Media, Sinkholes And The Uk National Karst Database, Vanessa J. Banks Dr, Helen J. Reeves, Emma K. Ward, Emma R. Raycraft, Hannah V. Gow, David J R Morgan, Donald G. Cameron Oct 2015

Media, Sinkholes And The Uk National Karst Database, Vanessa J. Banks Dr, Helen J. Reeves, Emma K. Ward, Emma R. Raycraft, Hannah V. Gow, David J R Morgan, Donald G. Cameron

Sinkhole Conference 2015

The British Geological Survey (BGS) maintains a number of databases that feed into hazard susceptibility assessments, including karst, landslide and mining susceptibility. The winter period from December 2013 to January 2014 was one of, if not the most, exceptional periods of winter rainfall in the last 248 years for England and Wales. During this period the Jet Stream diverted easterly tracking cyclones along a more southerly route than is usual across the United Kingdom (UK). This resulted in south-east and central-southern England experiencing total rainfall values of 372.2 mm for this period, which was the wettest two-month period since 1910. …

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Creation Of A Map Of Paleozoic Bedrock Springsheds In Southeast Minnesota, Jeffrey A. Green, E. Calvin Alexander Jr. Oct 2015

Creation Of A Map Of Paleozoic Bedrock Springsheds In Southeast Minnesota, Jeffrey A. Green, E. Calvin Alexander Jr.

Sinkhole Conference 2015

Springs are groundwater discharge points that serve as vital coldwater sources for streams in southeast Minnesota. The springs generally emanate from Paleozoic carbonate and siliciclastic bedrock aquifers. Use of systematic dye tracing began in the 1970s and continues through the present as a standard method for investigating karst hydrology and to map springsheds,. The work was accelerated in 2007 because of increased funding from the State of Minnesota’s Environment and Natural Resources Trust Fund. A compilation springshed map of dye traces conducted over the last several decades has been assembled for the region. In southeast Minnesota, the springs are the …

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Using Electrical Resistivity Imaging To Characterize Karst Hazards In Southeastern Minnesota Agricultural Settings, Toby Dogwiler, Blake Lea Oct 2015

Using Electrical Resistivity Imaging To Characterize Karst Hazards In Southeastern Minnesota Agricultural Settings, Toby Dogwiler, Blake Lea

Sinkhole Conference 2015

Much of the Driftless Area of southeastern Minnesota is underlain by karstified carbonate bedrock. Land use in this karst terrain is dominated by agriculture, including row crop and dairy operations. The karst in this region is often mantled with up to 15 m of soil and unconsolidated sediments. As a result, underlying karst hazards such as incipient sinkholes are often hidden until they are suddenly revealed by the collapse of subsurface voids. Regionally, the economics of the dairy industry is causing a trend toward the consolidation and expansion of existing operations. As concentrated animal feeding operations (CAFO) or feedlots expand, …

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The Application Of Passive Seismic Techniques To The Detection Of Buried Hollows, Michael G. Raines, Vanessa J. Banks, Jonathan E. Chambers, Philip E.F. Collins, Peter F. Jones, Dave J.R. Morgan, James B. Riding, Katherine Royse Oct 2015

The Application Of Passive Seismic Techniques To The Detection Of Buried Hollows, Michael G. Raines, Vanessa J. Banks, Jonathan E. Chambers, Philip E.F. Collins, Peter F. Jones, Dave J.R. Morgan, James B. Riding, Katherine Royse

Sinkhole Conference 2015

Pilot studies involving the use of passive seismic techniques in a range of geological settings and applications (e.g., mapping bedrock, studies of soil erosion and Quaternary surficial mapping) have shown that it is a versatile, non-invasive and economic technique. This paper presents the findings of three case studies that used passive seismic techniques for the detection and characterization of buried hollows in carbonate rocks: 1) a buried hollow in the Cretaceous chalk at Ashford Hill in the Kennet Valley, a tributary of the River Thames, UK; 2) buried karst in the foundation excavations for wind turbines in Carboniferous limestone at …

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Pre-Event And Post-Formation Ground Movement Associated With The Bayou Corne Sinkhole, Cathleen E. Jones, Ronald Blom Oct 2015

Pre-Event And Post-Formation Ground Movement Associated With The Bayou Corne Sinkhole, Cathleen E. Jones, Ronald Blom

Sinkhole Conference 2015

We discuss measurements of the precursory and post-formation ground displacement in the vicinity of the Bayou Corne, Louisiana, sinkhole made using interferometric synthetic aperture radar (InSAR) and data from the L-band UAVSAR instrument. Large precursory movement was observed at the sinkhole site and shown to be predominantly horizontal in direction, in contrast to sinkhole precursors previously detected with InSAR, all of which indicated vertical deformation. Here we discuss how two opposing imaging directions were used to determine the precursory horizontal movement, and use the same technique to look at the progression of post-formation ground displacement around the expanding sinkhole during …

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Investigation Of A Sinkhole In Ogle County, Northwestern Illinois, Using Near-Surface Geophysical Techniques, Philip J. Carpenter, Lauren Schroeder Oct 2015

Investigation Of A Sinkhole In Ogle County, Northwestern Illinois, Using Near-Surface Geophysical Techniques, Philip J. Carpenter, Lauren Schroeder

Sinkhole Conference 2015

A sinkhole measuring 40 m in diameter and up to 6.5 m deep occurs within the Nachusa Grasslands, near the town of Franklin Grove, northwestern Illinois. This area, dedicated to prairie conservation and restoration, is owned and operated by The Nature Conservancy. Several meters of unconsolidated sand, gravel, and clay overlie the St. Peter sandstone, beneath which lies karstic Prairie du Chien dolomite. Investigations included EM conductivity profiles, resistivity soundings, 2D resistivity, and ground- penetrating radar (GPR), supplemented by conductivity logs, soil cores, and tree core studies. These data indicate the sandstone averages about 5 m deep near the sinkhole …

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Characterization Of Karst Terrain Using Geophysical Methods Based On Sinkhole Analysis: A Case Study Of The Anina Karstic Region (Banat Mountains, Romania), Laurentiu Artugyan, Adrian C. Ardelean, Petru Urdea Oct 2015

Characterization Of Karst Terrain Using Geophysical Methods Based On Sinkhole Analysis: A Case Study Of The Anina Karstic Region (Banat Mountains, Romania), Laurentiu Artugyan, Adrian C. Ardelean, Petru Urdea

Sinkhole Conference 2015

To understand karst topography, we must determine both the nature and the factors that are defining dissolution processes in soluble rocks, as well as the drainage network resulting from these processes. The goal of this paper is to understand the underground drainage direction configuration and, also, the factors that are involved in surface water drainage of the Anina karstic region. In this study we used two complementary geophysical methods, spontaneous potential (SP) and ground penetrating radar (GPR), applied in 5 sinkholes with a funnel shaped aspect. Four of these sinkholes are circular and one of them is elongated NW-SE direction. …

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Rollalong Resistivity Surveys Reveal Karstic Paleotopography Developed On Near-Surface Gypsum Bedrock: Lower Pecos Valley, Southeastern New Mexico, Lewis Land Oct 2015

Rollalong Resistivity Surveys Reveal Karstic Paleotopography Developed On Near-Surface Gypsum Bedrock: Lower Pecos Valley, Southeastern New Mexico, Lewis Land

Sinkhole Conference 2015

Following flooding in September 2013, several areas in northern Eddy County, New Mexico were damaged by multiple sinkhole collapses. We conducted rollalong electrical resistivity (ER) surveys for subsurface cavities parallel to roads within and near the community of Lakewood, NM to guide road repairs. The rollalong method allowed us to generate exceptionally long, continuous ER profiles of the survey area. ER surveys attained a maximum exploration depth of 55 to 62 meters over a lateral extent of ~1000 meters, revealing an unconformable surface developed on gypsum bedrock, punctuated by shallow depressions. Subsurface stratigraphy, including clay-rich valley fill sediments, and mudstone …

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Goliath’S Cave, Minnesota: Epigenic Modification And Extension Of Pre-Existing Hypogenic Conduits, E. Calvin Alexander Jr., Scott C. Alexander, Kelton Barr, Andrew Luhmann, Cale Anger Oct 2015

Goliath’S Cave, Minnesota: Epigenic Modification And Extension Of Pre-Existing Hypogenic Conduits, E. Calvin Alexander Jr., Scott C. Alexander, Kelton Barr, Andrew Luhmann, Cale Anger

Sinkhole Conference 2015

Goliath’s Cave is developed in the Ordovician Dubuque and Stewartville Formations of the Galena Group in Fillmore County, MN. The cave currently functions as an epigenic karst system with allogenic surface water sinking into the cave and a vadose stream running through the cave and resurging at springs a few kilometers away. Passages in the cave are locally controlled by vertical joints in the nearly flat-lying carbonate bedrock, but the water flow directions often do not correspond to the systematic joint directions. The cave contains straight, joint-controlled passages that appear to pre-date the current epigenic drainage systems. These old passages …

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Relay Ramp Structures And Their Influence On Groundwater Flow In The Edwards And Trinity Aquifers, Hays And Travis Counties, Central Texas, Brian B. Hunt, Brian A. Smith, Alan Andrews, Douglas Wierman, Alex S. Broun, Marcus Gary Oct 2015

Relay Ramp Structures And Their Influence On Groundwater Flow In The Edwards And Trinity Aquifers, Hays And Travis Counties, Central Texas, Brian B. Hunt, Brian A. Smith, Alan Andrews, Douglas Wierman, Alex S. Broun, Marcus Gary

Sinkhole Conference 2015

The Cretaceous Edwards and Middle Trinity Aquifers of central Texas are critical groundwater resources for human and ecological needs. These two major karst aquifers are stratigraphically stacked (Edwards over Trinity) and structurally juxtaposed (normal faulting) in the Balcones Fault Zone (BFZ). Studies have long recognized the importance of faulting on the development of the karstic Edwards Aquifer. However, the influence of these structures on groundwater flow is unclear as groundwater flow appears to cross some faults, but not others. This study combines structural and hydrological data to help characterize the potential influence of faults and relay ramps on groundwater flow …

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Down The Rabbit Hole: Identifying Physical Controls On Sinkhole Formation In The Uk, Tamsin Green Oct 2015

Down The Rabbit Hole: Identifying Physical Controls On Sinkhole Formation In The Uk, Tamsin Green

Sinkhole Conference 2015

Heavy precipitation in the UK in February 2014 induced ground subsidence and consequently a rapid increase in the frequency of sinkhole occurrences. These new sinkhole collapses emphasise the need to further analyse the causes of the increased occurrence by investigating the relative importance of various surficial factors. Malham and the Mendips are two areas of particular interest, since both are underlain by limestone bedrock and are susceptible to subsidence. This is due to limestone being primarily permeable in joints, and so it dissolves to form an extensive network of karstic caves. It was therefore useful to compare two sites of …

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The Sandstone Karst Of Pine County, Minnesota, Beverley Lynn Shade, Emmit Calvin Alexander Jr., Scott C. Alexander Oct 2015

The Sandstone Karst Of Pine County, Minnesota, Beverley Lynn Shade, Emmit Calvin Alexander Jr., Scott C. Alexander

Sinkhole Conference 2015

The glaciated, forested landscape of central Pine County in east-central Minnesota contains a series of sinkholes, stream sinks, springs and caves. The features are formed in Precambrian Hinckley Sandstone and overlying unconsolidated glacial deposits. This is a sandstone karst. The features serve the same function as in carbonate karst terrains: sinkholes and caves focus recharge into a heterogeneous subterranean flow system that discharges into springs. The Hinckley Sandstone is a quartz arenite. No carbonate grains or cements have been found in sandstone samples from the sinkhole area, nor is there evidence that calcite solution controls bedrock permeability. Three parameters appear …

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Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison Oct 2015

Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison

Sinkhole Conference 2015

Extensive foundation preparations during construction of the Wolf Creek Dam concrete masonry section precluded the need for additional rehabilitation to mitigate seepage through karstic limestone bedrock. Wolf Creek Dam on the Cumberland River in southern Kentucky has become well known for karst related seepage issues underneath the embankment section, and yet has had little to no seepage issues associated with the concrete masonry portion of the dam. Post-construction efforts to control seepage underneath the embankment began in 1967 and 1968. Emergency grouting commenced and continued through 1970. Between 1975 and 1979 a more permanent solution of a concrete diaphragm cut-off …

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Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett Oct 2015

Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett

Sinkhole Conference 2015

The US Army required construction of a 2,787.1 square meters (30,000 sf) maintenance facility supported on shallow foundations at the Fort Campbell Military Installation. During the subsurface investigation a seven foot air-filled void was encountered in the bedrock within the building footprint. Electrical Resistivity Imaging (ERI) was conducted in an attempt to determine the lateral extent of the encountered void and to establish the general prevalence of karst features at the site. Due to uncertainty in the subsurface conditions, a rock treatment and soil modification program was developed which consisted of a series of targeted exploratory grout holes advanced in …

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Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum Oct 2015

Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum

Sinkhole Conference 2015

Sinkhole formation is a common occurrence in northeast Iowa, and U.S. 18 in Cerro Gordo County was constructed over an area where sinkhole formation had only been locally known. It had not been recorded or identified in the Iowa DNR database at the time. Since 2004, sinkholes have developed along the right of way. Geophysical surveys contributed very little in the identifying the cause. However a Soil Survey (drilling program) identified numerous voids within carbonate bedrock. The soil borings indicated that shale overlying the carbonate rock has been removed/eroded, and resulted in the development of a karst subsurface through the …

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Concepts For Geotechnical Investigation In Karst, Joseph A. Fischer, Joseph J. Fischer Oct 2015

Concepts For Geotechnical Investigation In Karst, Joseph A. Fischer, Joseph J. Fischer

Sinkhole Conference 2015

There seems to be a lack of recognition in the literature that addresses the variety of karst in the United States of America and some of its offshore territories. For example, there are the well-known solutioned carbonates of Florida and the Caribbean, but there are also the somewhat older, harder carbonates of St. Croix, U.S.V.I. Even Florida’s recently deposited karst varies from region to region. There are also the ancient, flat-lying carbonates of the interior craton that often have semi-horizontal cavities resulting from variations in ground water levels affecting bedding and the contorted rocks of the Appalachians with its apparently …

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Determination Of The Relationship Of Nitrate To Discharge And Flow Systems In North Florida Springs, Sam B. Upchurch Oct 2015

Determination Of The Relationship Of Nitrate To Discharge And Flow Systems In North Florida Springs, Sam B. Upchurch

Sinkhole Conference 2015

The Suwannee River Water Management District has collected quarterly discharge and water quality data from 30 1st and 2nd magnitude springs in the Suwannee River Basin since 1998. These data were collected quarterly well into the late 2000s and constitute a valuable database for characterizing spring discharge behavior. Trend and correlation analyses were used to compare the relationships of NO3- + NO2- (nitrate in this paper), specific conductance, and spring discharge. Trends were considered significant if alpha levels of the trend slopes were ≤ 0.05. Data from 50% of the springs show that nitrate concentrations increase as discharge from the …

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Tracking Of Karst Contamination Using Alternative Monitoring Technologies: Hidden River Cave Kentucky, Caren Raedts, Christopher Smart Oct 2015

Tracking Of Karst Contamination Using Alternative Monitoring Technologies: Hidden River Cave Kentucky, Caren Raedts, Christopher Smart

Sinkhole Conference 2015

Karst groundwater contamination presents great challenges for efficient monitoring because of rapid, discrete transport and the diversity of contaminants. Here a low cost approach is described and applied to Hidden River Cave, Kentucky, where a long history of contamination has been experienced. Local knowledge was acquired through informal interviews and coupled with observations of contaminant residues, faunal distributions and fluorescence spectra in the cave. The resulting patterns were interpreted using Google Earth and Street View to identify specific contaminant sources in the affected sub-catchment of the cave. Despite success in matching contaminant sources with the contamination history and pattern, the …

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Karst Influence In The Creation Of A Pfc Megaplume, Virginia Yingling Oct 2015

Karst Influence In The Creation Of A Pfc Megaplume, Virginia Yingling

Sinkhole Conference 2015

Perfluorochemicals (PFCs) are fully-fluorinated organic chemicals used to produce a wide range of industrial and commercial products. Their extreme persistence and mobility in the environment and nearly ubiquitous presence in humans and wildlife has raised serious concerns regarding their environmental and human health effects. In the 1940s to 1970s, PFC-bearing wastes were disposed of in three unlined landfills in Washington County, Minnesota. The resulting co-mingled PFC plumes created a “megaplume” that contaminated over 250 km2 of groundwater and four major drinking water aquifers; affecting eight municipal water supply systems and thousands of private wells. Site investigations revealed that karst features, …

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Evaluation Of Veterinary Pharmaceuticals And Iodine For Use As A Groundwater Tracer In Hydrologic Investigation Of Contamination Related To Dairy Cattle Operations, Larry Boot Pierce, Honglin Shi Oct 2015

Evaluation Of Veterinary Pharmaceuticals And Iodine For Use As A Groundwater Tracer In Hydrologic Investigation Of Contamination Related To Dairy Cattle Operations, Larry Boot Pierce, Honglin Shi

Sinkhole Conference 2015

Standard groundwater tracers such as Rhodamine WT, Fluorescein, Eosin and Tinopal CBX effectively provide a snapshot of hydrological conditions over a brief period of time and in a tightly controlled setting. However, in complex environmental situations with multiple potential sources, groundwater hydrologists are often seeking groundwater tracers that have extended longevity in the natural environment and the ability to directly pinpoint source locations. After reviewing operations of the nearby dairy it was determined that emerging contaminants, specifically two bovine veterinary pharmaceuticals (antibiotics), cephapirin sodium (CEPNa) and cephapirin benzathine (CEPB), and a sanitation agent, elemental Iodine (I) may have potential as …

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Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg Oct 2015

Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg

Sinkhole Conference 2015

Residential building construction along the Mississippi River bluffs in the 1970s created a unique enclosed outcrop of the Late Ordovician Platteville Formation at Lilydale, Minnesota. This outcrop was examined in early 2013 after a newly-formed spring flooded an elevator shaft the previous year, drawing attention to the foundation conditions. The Lexington Riverside property is a six story condominium complex constructed within the top of the bluff. A two-level underground parking garage was built into the bluff. Bedrock was mechanically excavated to accommodate the construction of the building, creating an unweathered rock surface. The space between the structure and the excavated …

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Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner Oct 2015

Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner

Sinkhole Conference 2015

The Mitchell Aquifer averages 80m in thickness and underdrains a karst region in the Crawford Upland and Mitchell Plateau region in south-central Indiana (110,000 km2). The Springville Escarpment is a transitional boundary between the upland and plateau. Cave stream linking between cave tiers in the aquifer and correlation of cave tier inception horizons to a base level decline surface is interpreted for the Kirby Watershed, encompassing the prekarst headland of Indian Creek (42km2). The watershed was severed from lower Indian Creek at Eller Col by limestone cavern drainage on the ridge between White River and East Fork. Correlation of recharge …

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Using Nitrate, Chloride, Sodium, And Sulfate To Calculate Groundwater Age, Kimm Crawford, Terry Lee Oct 2015

Using Nitrate, Chloride, Sodium, And Sulfate To Calculate Groundwater Age, Kimm Crawford, Terry Lee

Sinkhole Conference 2015

Regression analysis is used to identify monotonic trends to assign water age using ion data from two large well water databases from southeast Minnesota (SE MN). Nitrate (NO3-N), chloride (Cl), sodium (Na), and sulfate (SO4) ions in the commonly used aquifers in SE MN can be used as groundwater tracers since they are either entirely or partly anthropogenic in their sources, their loading occurs on a regional scale, and they are almost entirely conserved. Ion concentrations over time are used to establish six trend patterns. Two patterns are unchanging (background and stable above background), and four are changing (linear up, …

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Conduit Flow In The Cambrian Lone Rock Formation, Southeast Minnesota, U.S.A., John D. Barry, Jeffrey A. Green, Julia R. Steenberg Oct 2015

Conduit Flow In The Cambrian Lone Rock Formation, Southeast Minnesota, U.S.A., John D. Barry, Jeffrey A. Green, Julia R. Steenberg

Sinkhole Conference 2015

The karst lands of southeast Minnesota contain more than one hundred trout streams that receive perennial discharge from Paleozoic bedrock springs. Several of the Paleozoic bedrock units that provide discharge are karst aquifers. Field investigations into the flow characteristics of these formations have been conducted using fluorescent dyes to map groundwater springsheds and characterize groundwater flow velocities for use in water resource protection. Recent field work has focused on the Cambrian Lone Rock Formation, a siliciclastic unit consisting of very fine-grained sandstone and siltstone with minor beds of shale and dolostone. The formation is mapped within tributary valleys of the …

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Hydrologic And Geochemical Dynamics Of Vadose Zone Recharge In A Mantled Karst Aquifer: Results Of Monitoring Drip Waters In Mystery Cave, Minnesota, Daniel H. Doctor, E. Calvin Alexander Jr., Roy Jameson, Scott C. Alexander Oct 2015

Hydrologic And Geochemical Dynamics Of Vadose Zone Recharge In A Mantled Karst Aquifer: Results Of Monitoring Drip Waters In Mystery Cave, Minnesota, Daniel H. Doctor, E. Calvin Alexander Jr., Roy Jameson, Scott C. Alexander

Sinkhole Conference 2015

Caves provide direct access to flows through the vadose zone that recharge karst aquifers. Although many recent studies have documented the highly dynamic processes associated with vadose zone flows in karst settings, few have been conducted in mantled karst settings, such as that of southeastern Minnesota. Here we present some results of a long-term program of cave drip monitoring conducted within Mystery Cave, Minnesota. In this study, two perennial ceiling drip sites were monitored between 1997 and 2001. The sites were located about 90 m (300 ft) apart along the same cave passage approximately 18 m (60 ft) below the …

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