Kentucky

Introduction 3 Purpose and scope of report 4 Acknowledgments 5 Properties of water 5 Composition of the earth's crust 6 Water as a geochemical agent The role of water in erosion Chemistry of weathering processes Collection of quality-of-water data Collection of water samples Surface-water sampling Ground-water sampling Completeness of sample coverage Analyses of water samples Field testing of water Electric logs as indicators of ground-water quality Laboratory procedures Expression of water analyses Analyses reported in terms of hypothetical combinations Analyses expressed in terms of ions Determinations included in analyses Units used in reporting analyses Weight-per-weight units Weight-per-volume units Equivalent-weight units Composition of anhydrous residue Parts per million as calcium carbonate Comparison of units of expression Significance of properties and constituents reported in water analyses_ _ Specific electrical conductance Units for reporting conductance Physical basis of conductance Range of conductance values Accuracy and reproducibility of conductance values Hydrogen-ion concentration (pH) Hydrolysis Buffered solutions Interpretation of pH data Range of pH values Accuracy and reproducibility of pH values Color Sources and significance of color in water 49 Residue on evaporition 49 Theoretical basis of determination 50 Range of concentration 51 Accuracy and reproducibility of results 51 III Significance of properties and constituents reported in water analyses-Continued Acidity Sources of acidity of natural water Chemistry of acidity determination Range of concentration Reproducibility of acidity data Sulfate Sources of sulfate in natural water Chemistry of sulfate in natural water Range of concentration Accuracy and reproducibility of results Chloride Sources of chloride in water Chemistry of chloride in natural water Oceanic chloride Juvenile chloride Cyclic chloride Range of concentration Accuracy and reproducibility of results Fluoride Source of fluoride in water Chemistry of fluoride in natural water Range of concentration Accuracy and reproducibility of results Nitrate Source of nitrate in water Chemistry of nitrate in natural water 116 Range of concentration Accuracy and reproducibility of results Phosphate Sources of phosphate Chemistry of phosphate in natural water 119 Range of concentration 120 Accuracy and reproducibility of results 120 Boron 120 Sources of boron 120 Chemistry of boron in natural water Range of concentration 122 Accuracy and reproducibility of results 122 Trace or minor constituents-Cations 124 Heavy metals 124 Titanium 124 Chromium 124 Zinc 125 Nickel and cobalt 126 Copper 126 Tin 127 Lead 127 Cadmium 128 Mercury 128 Arsenic 129 Selenium 130 Significance of properties and constituents reported in water analyses-Continued Trace or minor constituents-Cations-Continued Alkaline-earth metals Beryllium Strontium Barium Alkali metals and ammonium Lithium Rubidium Cesium Ammonium Radioactive components Uranium Radium Radon Thorium Trace or minor constituents-Anions Bromide Iodide Sulfite and thiosulf ate Total dissolved solids-Computed Chemistry of dissolved solids determination Accuracy and reproducibility of results Dissolved gases Biochemical oxygen demand Hardness Utilization Range of concentration Accuracy and reproducibility of results Percent sodium Sodium-adsorption ratio Density Organization and study of water-analysis data Evaluation of water analyses Tabulation Study techniques Inspection and comparison Use of ratios Use of averages 156 Palmer's geochemical classification 162 Graphical representation 164 Scatter diagrams 165 Ionic-concentration diagrams 168 Percentage-composition diagrams Frequency diagrams Chemical analyses plotted against nonchemical variables 186 Hydrographs 186 Dissolved-solids rating curves 188 Water-quality profiles 192 Quality-of-water maps 192 Selection of study techniques 10. Effect of temperature on solubility of calcium carbonate (calcite) in water in the presence of CO2 VIII CONTENTS Page FIGURE 11. Solubility of magnesium carbonate in water at 25C in the presence of CO2 81 12. Relation of conductance to chloride, hardness, and sulfate concentrations, Gila River at Bylas, Ariz., Oct. 1, 1943 to Sept. 30, 1944 13. Sodium-chloride relationship, Gila River at Bylas, Ariz., Oct. 1, 1943, to Sept. 30, 1944 14. Analyses represented by vertical bar graphs of equivalents per million 15. Analyses represented by bar graphs of parts per million 16. Bar graph of equivalents per million which also shows hardness values in parts per million 17. Analyses in equivalents per million represented by vectors__ _ 18. Analyses represented by patterns based on equivalents per million 19. Analyses represented by linear plotting of cumulative percentage composition based on parts per million 20. Analyses represented by logarithmic plotting of concentrations in parts per million 21. Analyses represented by circular diagrams subdivided on the basis of percent of total equivalents per million 22. Analyses represented by bar-patterns based on percent of total equivalents per million 23. Analyses represented by patterns drawn on radial coordinates.. 24. Analyses represented by three points plotted in trilinear diagram (after A. M. Piper) 25. Number of samples having percent sodium within ranges indicated, San Simon artesian basin, Ariz 26. Cumulative frequency curve of specific conductance, Allegheny, Monongahela and Ohio River waters, Pittsburgh area, Pennsylvania, 1944-50 27. Specific conductance of daily samples and daily mean discharge, San Francisco River at Clifton, Ariz., Oct. 1, 1943 to Sept. 30, 1944 28. Bicarbonate, sulfate, hardness, and pH of samples collected in cross section of Susquehanna River at Harrisburg, Pa., July 8, 1947 29. Temperature and dissolved solids of water in Lake Mead in Virgin and Boulder Canyons, 1948 194 30. Total concentration and hardness of water from deeper wells in Prairie Creek Unit, Nebr 31. Ratio of alkalinity to sulfate in water from unconsolidated deposits in the Torrington area, Nebr 32. Map of portions of Apache and Navajo counties, Ariz., showing mineral content of ground water in the Coconino sandstone_ 198 33. Analyses of waters associated with igneous rocks 206 34. Analyses of waters associated with resistate sediments 209 35. Analyses of waters associated with hydrolyzate sediments_ _ _ 36. Weighted-average analyses for Rio Grande at San Acacia, N. Mex., for two periods in the 1945-46 water year 212 37. Analyses of waters associated with precipitate-type sediments.. 38. Analyses of waters associated with evaporate sediments 215 39. Analyses of waters associated with metamorphic rocks 217 40. Diagram for use in interpreting the analysis of irrigation water_ 251 2 CHEMICAL CHARACTERISTICS OF NATURAL WATER

@misc{doi103133wsp1473ed1,
    author = "Hem, John David",
    title = "Study and interpretation of the chemical characteristics of natural water",
    year = "1959",
    abstract = "Introduction 3 Purpose and scope of report 4 Acknowledgments 5 Properties of water 5 Composition of the earth's crust 6 Water as a geochemical agent The role of water in erosion Chemistry of weathering processes Collection of quality-of-water data Collection of water samples Surface-water sampling Ground-water sampling Completeness of sample coverage Analyses of water samples Field testing of water Electric logs as indicators of ground-water quality Laboratory procedures Expression of water analyses Analyses reported in terms of hypothetical combinations Analyses expressed in terms of ions Determinations included in analyses Units used in reporting analyses Weight-per-weight units Weight-per-volume units Equivalent-weight units Composition of anhydrous residue Parts per million as calcium carbonate Comparison of units of expression Significance of properties and constituents reported in water analyses\_ \_ Specific electrical conductance Units for reporting conductance Physical basis of conductance Range of conductance values Accuracy and reproducibility of conductance values Hydrogen-ion concentration (pH) Hydrolysis Buffered solutions Interpretation of pH data Range of pH values Accuracy and reproducibility of pH values Color Sources and significance of color in water 49 Residue on evaporition 49 Theoretical basis of determination 50 Range of concentration 51 Accuracy and reproducibility of results 51 III Significance of properties and constituents reported in water analyses-Continued Acidity Sources of acidity of natural water Chemistry of acidity determination Range of concentration Reproducibility of acidity data Sulfate Sources of sulfate in natural water Chemistry of sulfate in natural water Range of concentration Accuracy and reproducibility of results Chloride Sources of chloride in water Chemistry of chloride in natural water Oceanic chloride Juvenile chloride Cyclic chloride Range of concentration Accuracy and reproducibility of results Fluoride Source of fluoride in water Chemistry of fluoride in natural water Range of concentration Accuracy and reproducibility of results Nitrate Source of nitrate in water Chemistry of nitrate in natural water 116 Range of concentration Accuracy and reproducibility of results Phosphate Sources of phosphate Chemistry of phosphate in natural water 119 Range of concentration 120 Accuracy and reproducibility of results 120 Boron 120 Sources of boron 120 Chemistry of boron in natural water Range of concentration 122 Accuracy and reproducibility of results 122 Trace or minor constituents-Cations 124 Heavy metals 124 Titanium 124 Chromium 124 Zinc 125 Nickel and cobalt 126 Copper 126 Tin 127 Lead 127 Cadmium 128 Mercury 128 Arsenic 129 Selenium 130 Significance of properties and constituents reported in water analyses-Continued Trace or minor constituents-Cations-Continued Alkaline-earth metals Beryllium Strontium Barium Alkali metals and ammonium Lithium Rubidium Cesium Ammonium Radioactive components Uranium Radium Radon Thorium Trace or minor constituents-Anions Bromide Iodide Sulfite and thiosulf ate Total dissolved solids-Computed Chemistry of dissolved solids determination Accuracy and reproducibility of results Dissolved gases Biochemical oxygen demand Hardness Utilization Range of concentration Accuracy and reproducibility of results Percent sodium Sodium-adsorption ratio Density Organization and study of water-analysis data Evaluation of water analyses Tabulation Study techniques Inspection and comparison Use of ratios Use of averages 156 Palmer's geochemical classification 162 Graphical representation 164 Scatter diagrams 165 Ionic-concentration diagrams 168 Percentage-composition diagrams Frequency diagrams Chemical analyses plotted against nonchemical variables 186 Hydrographs 186 Dissolved-solids rating curves 188 Water-quality profiles 192 Quality-of-water maps 192 Selection of study techniques 10. Effect of temperature on solubility of calcium carbonate (calcite) in water in the presence of CO2 VIII CONTENTS Page FIGURE 11. Solubility of magnesium carbonate in water at 25C in the presence of CO2 81 12. Relation of conductance to chloride, hardness, and sulfate concentrations, Gila River at Bylas, Ariz., Oct. 1, 1943 to Sept. 30, 1944 13. Sodium-chloride relationship, Gila River at Bylas, Ariz., Oct. 1, 1943, to Sept. 30, 1944 14. Analyses represented by vertical bar graphs of equivalents per million 15. Analyses represented by bar graphs of parts per million 16. Bar graph of equivalents per million which also shows hardness values in parts per million 17. Analyses in equivalents per million represented by vectors\_\_ \_ 18. Analyses represented by patterns based on equivalents per million 19. Analyses represented by linear plotting of cumulative percentage composition based on parts per million 20. Analyses represented by logarithmic plotting of concentrations in parts per million 21. Analyses represented by circular diagrams subdivided on the basis of percent of total equivalents per million 22. Analyses represented by bar-patterns based on percent of total equivalents per million 23. Analyses represented by patterns drawn on radial coordinates.. 24. Analyses represented by three points plotted in trilinear diagram (after A. M. Piper) 25. Number of samples having percent sodium within ranges indicated, San Simon artesian basin, Ariz 26. Cumulative frequency curve of specific conductance, Allegheny, Monongahela and Ohio River waters, Pittsburgh area, Pennsylvania, 1944-50 27. Specific conductance of daily samples and daily mean discharge, San Francisco River at Clifton, Ariz., Oct. 1, 1943 to Sept. 30, 1944 28. Bicarbonate, sulfate, hardness, and pH of samples collected in cross section of Susquehanna River at Harrisburg, Pa., July 8, 1947 29. Temperature and dissolved solids of water in Lake Mead in Virgin and Boulder Canyons, 1948 194 30. Total concentration and hardness of water from deeper wells in Prairie Creek Unit, Nebr 31. Ratio of alkalinity to sulfate in water from unconsolidated deposits in the Torrington area, Nebr 32. Map of portions of Apache and Navajo counties, Ariz., showing mineral content of ground water in the Coconino sandstone\_ 198 33. Analyses of waters associated with igneous rocks 206 34. Analyses of waters associated with resistate sediments 209 35. Analyses of waters associated with hydrolyzate sediments\_ \_ \_ 36. Weighted-average analyses for Rio Grande at San Acacia, N. Mex., for two periods in the 1945-46 water year 212 37. Analyses of waters associated with precipitate-type sediments.. 38. Analyses of waters associated with evaporate sediments 215 39. Analyses of waters associated with metamorphic rocks 217 40. Diagram for use in interpreting the analysis of irrigation water\_ 251 2 CHEMICAL CHARACTERISTICS OF NATURAL WATER",
    url = "https://doi.org/10.3133/wsp1473\_ed1",
    doi = "10.3133/wsp1473\_ed1",
    openalex = "W2064299399",
    references = "doi101001jama194502860360014004, doi101002j155188331936tb13785x, doi101002j155188331942tb19682x, doi101029tr022i003p00593, doi101029tr025i006p00914, doi101093aibsbulletin4314a, doi101130001676061957681637twovo20co2, doi102118951376g, doi1023071438154, openalexw3121961717"
}

Stream water chemistry varies hyperbolically with stream discharge through four decades of discharge change within the Hubbard Brook Experimental Forest, New Hampshire. This dilution process is most simply explained by the mixing of rain water or surface water with deeper soil water. The resultant mixture of waters subsequently appears as stream water. Sodium and silica concentrations in stream water are markedly diluted during high discharge periods while hydrogen ion, aluminum, and nitrate concentrations are increased. Magnesium, calcium, sulfate, chloride and potassium concentrations are changed very little by stream discharge variations. During the summer, biologic activity measurably reduces the concentration of nitrate and potassium in stream water.

@article{doi101029wr005i006p01353,
    author = "Johnson, Noye M. and Likens, Gene E. and Bormann, Franz–Josef and Fisher, Donald and Pierce, Robert S.",
    title = "A Working Model for the Variation in Stream Water Chemistry at the Hubbard Brook Experimental Forest, New Hampshire",
    year = "1969",
    journal = "Water Resources Research",
    abstract = "Stream water chemistry varies hyperbolically with stream discharge through four decades of discharge change within the Hubbard Brook Experimental Forest, New Hampshire. This dilution process is most simply explained by the mixing of rain water or surface water with deeper soil water. The resultant mixture of waters subsequently appears as stream water. Sodium and silica concentrations in stream water are markedly diluted during high discharge periods while hydrogen ion, aluminum, and nitrate concentrations are increased. Magnesium, calcium, sulfate, chloride and potassium concentrations are changed very little by stream discharge variations. During the summer, biologic activity measurably reduces the concentration of nitrate and potassium in stream water.",
    url = "https://doi.org/10.1029/wr005i006p01353",
    doi = "10.1029/wr005i006p01353",
    openalex = "W2117327398"
}

ABSTRACT Insights into the chemical and Hydrogeologie history of spring waters in carbonate rocks can be gained from a study of the chemical quality of such waters and of the waters which feed springs. The median Ca 2+ /Mg 2+ ratio was 3.4 in 29 spring waters from folded and faulted carbonate rocks near State College, Pennsylvania, indicating ground‐water flow predominantly in limestone. The mean dissolved oxygen content was 7.7 mg/1 or 71% of saturation consistent with subsurface flow chiefly under water table conditions. Most of the dissolved solids (as specific conductance) including pollutants such as Cl and NO 3 were added to spring waters during ground‐water flow. Specific conductances ranged from 180 to 476 micromhos, with a mean of 347 micromhos. CO 2 pressures were from 10 −1.9 to 10 −2.6 atm with a mean of 10 −2.2. atm. The CO 2, which is chiefly introduced as gas by downward diffusion from the soil zone, gives spring waters the capacity to hold about 3 times more hardness and alkalinity than streams in equilibrium with the atmosphere. However, all spring waters were undersaturated with respect to calcite and dolomite because of their short residence times as ground water. Dye tracing of ground‐water feeding springs in two drainage basins gave residence times of 2–6 days for subsurface flows of about 4,000 feet. The specific conductance and carbonate saturation data indicate that ground‐water residence times of the 29 spring waters average somewhat longer than 2–6 days.

@article{doi101111j174565841970tb01302x,
    author = "Jacobson, R.L. and Langmuir, Donald",
    title = "The Chemical History of Some Spring Waters in Carbonate Rocks a",
    year = "1970",
    journal = "Ground Water",
    abstract = "ABSTRACT Insights into the chemical and Hydrogeologie history of spring waters in carbonate rocks can be gained from a study of the chemical quality of such waters and of the waters which feed springs. The median Ca 2+ /Mg 2+ ratio was 3.4 in 29 spring waters from folded and faulted carbonate rocks near State College, Pennsylvania, indicating ground‐water flow predominantly in limestone. The mean dissolved oxygen content was 7.7 mg/1 or 71\% of saturation consistent with subsurface flow chiefly under water table conditions. Most of the dissolved solids (as specific conductance) including pollutants such as Cl and NO 3 were added to spring waters during ground‐water flow. Specific conductances ranged from 180 to 476 micromhos, with a mean of 347 micromhos. CO 2 pressures were from 10 −1.9 to 10 −2.6 atm with a mean of 10 −2.2. atm. The CO 2, which is chiefly introduced as gas by downward diffusion from the soil zone, gives spring waters the capacity to hold about 3 times more hardness and alkalinity than streams in equilibrium with the atmosphere. However, all spring waters were undersaturated with respect to calcite and dolomite because of their short residence times as ground water. Dye tracing of ground‐water feeding springs in two drainage basins gave residence times of 2–6 days for subsurface flows of about 4,000 feet. The specific conductance and carbonate saturation data indicate that ground‐water residence times of the 29 spring waters average somewhat longer than 2–6 days.",
    url = "https://doi.org/10.1111/j.1745-6584.1970.tb01302.x",
    doi = "10.1111/j.1745-6584.1970.tb01302.x",
    openalex = "W2062869117"
}

@article{doi1010160022169471900011,
    author = "Shuster, Evan T. and White, William B.",
    title = "Seasonal fluctuations in the chemistry of lime-stone springs: A possible means for characterizing carbonate aquifers",
    year = "1971",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/0022-1694(71)90001-1",
    doi = "10.1016/0022-1694(71)90001-1",
    openalex = "W2166952165"
}

@article{doi1010160022169472901151,
    author = "Thrailkill, John",
    title = "Carbonate chemistry of aquifer and stream water in Kentucky",
    year = "1972",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/0022-1694(72)90115-1",
    doi = "10.1016/0022-1694(72)90115-1",
    openalex = "W2013073528",
    references = "doi1010160016703771900196, doi101016b9780444408266500078, doi101016s0003267001807248, doi101021ja01250a059, doi101021ja01851a058, doi102475ajs2586402, openalexw1488282249, openalexw599354073, openalexw630529900"
}

A previous study of 14 carbonate springs in Nittany valley in central Pennsylvania showed that the feeder system for the springs could be characterized as conduit flow or diffuse flow on the basis of the variability in water chemistry. Saturation indices and CO 2 partial pressures calculated from the raw data of the previous study were then sorted into monthly groups and averaged. Conduit springwaters are always aggressive with respect to both calcite and dolomite, no seasonal trend being in evidence. The high variability reflects mostly variation in recharge, short residence time, and slow kinetics of equilibration between water and wall rock. Diffuse springwaters are somewhat aggressive with respect to calcite during the growing season but become somewhat supersaturated during the winter. Waters from diffuse‐flow springs in dolomite are nearly at saturation, whereas waters from diffuse‐flow springs in limestone are always undersaturated with respect to dolomite. The equilibrium CO 2 pressures of conduit springwaters show a regular seasonal trend having a pronounced maximum during the growing season. The CO 2 content of diffuse‐flow springs is highly variable, and although the summer maximum is present, the CO 2 content also reflects variations in the CO 2 production in the catchment areas of infiltrating waters.

@article{doi101029wr008i004p01067,
    author = "Shuster, Evan T. and White, William B.",
    title = "Source areas and climatic effects in carbonate groundwaters determined by saturation indices and carbon dioxide pressures",
    year = "1972",
    journal = "Water Resources Research",
    abstract = "A previous study of 14 carbonate springs in Nittany valley in central Pennsylvania showed that the feeder system for the springs could be characterized as conduit flow or diffuse flow on the basis of the variability in water chemistry. Saturation indices and CO 2 partial pressures calculated from the raw data of the previous study were then sorted into monthly groups and averaged. Conduit springwaters are always aggressive with respect to both calcite and dolomite, no seasonal trend being in evidence. The high variability reflects mostly variation in recharge, short residence time, and slow kinetics of equilibration between water and wall rock. Diffuse springwaters are somewhat aggressive with respect to calcite during the growing season but become somewhat supersaturated during the winter. Waters from diffuse‐flow springs in dolomite are nearly at saturation, whereas waters from diffuse‐flow springs in limestone are always undersaturated with respect to dolomite. The equilibrium CO 2 pressures of conduit springwaters show a regular seasonal trend having a pronounced maximum during the growing season. The CO 2 content of diffuse‐flow springs is highly variable, and although the summer maximum is present, the CO 2 content also reflects variations in the CO 2 production in the catchment areas of infiltrating waters.",
    url = "https://doi.org/10.1029/wr008i004p01067",
    doi = "10.1029/wr008i004p01067",
    openalex = "W2049629372"
}

@article{thrailkill1972carbonate,
    author = "Thrailkill, John",
    title = "Carbonate chemistry of aquifer and stream water in Kentucky",
    year = "1972",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/0022-1694(72)90115-1",
    doi = "10.1016/0022-1694(72)90115-1",
    number = "2",
    openalex = "W2013073528",
    pages = "93-104",
    volume = "16",
    references = "doi1010160016703771900196, doi101016b9780444408266500078, doi101016s0003267001807248, doi101021ja01250a059, doi101021ja01851a058, doi102475ajs2586402, openalexw1488282249, openalexw599354073, openalexw630529900"
}

@article{thrailkill1972carbonate1,
    author = "Thrailkill, J. V",
    title = "Carbonate chemistry of aquifer and stream water in Kentucky",
    year = "1972",
    journal = "Journal of Hydrology, v. 16, p. 93-104",
    note = "talkorigins\_source = {true}; raw\_reference = {Thrailkill, J. V., 1972, Carbonate chemistry of aquifer and stream water in Kentucky: Journal of Hydrology, v. 16, p. 93-104.}"
}

Waters within a carbonate aquifer have often been classified on a hydrologie basis. The significance of such grouping to the understanding of the geochemical processes acting in the aquifer is dependent on the classes having a distinctive chemistry. One hundred sixty‐six reliable chemical analyses of carbonate waters from Pennsylvania were grouped on a hydrologic basis, and the groupings were tested by a stepwise linear discriminant function analysis. Two parameters (degree of calcite saturation and equilibrium carbon dioxide partial pressure) are sufficient to distinguish the groups at the 0.005 confidence level and provide a reliable way to examine the geochemical evolution of the waters in the carbonate drainage basin.

@article{doi101029wr009i004p00949,
    author = "Drake, John J. and Harmon, Russell S.",
    title = "Hydrochemical environments of carbonate terrains",
    year = "1973",
    journal = "Water Resources Research",
    abstract = "Waters within a carbonate aquifer have often been classified on a hydrologie basis. The significance of such grouping to the understanding of the geochemical processes acting in the aquifer is dependent on the classes having a distinctive chemistry. One hundred sixty‐six reliable chemical analyses of carbonate waters from Pennsylvania were grouped on a hydrologic basis, and the groupings were tested by a stepwise linear discriminant function analysis. Two parameters (degree of calcite saturation and equilibrium carbon dioxide partial pressure) are sufficient to distinguish the groups at the 0.005 confidence level and provide a reliable way to examine the geochemical evolution of the waters in the carbonate drainage basin.",
    url = "https://doi.org/10.1029/wr009i004p00949",
    doi = "10.1029/wr009i004p00949",
    openalex = "W2172157664"
}

RELATIVE EFFICIENCY OF CARBONATE DISSOLUTION AND PRECIPITATION DURING DIAGENESIS: A PROGRESS REPORT ON THE ROLE OF SOLUTION CHEMISTRY

@article{doi102475ajs2742108,
    author = "Berner, Robert A. and Morse, John W.",
    title = "Dissolution kinetics of calcium carbonate in sea water; IV, Theory of calcite dissolution",
    year = "1974",
    journal = "American Journal of Science",
    abstract = "RELATIVE EFFICIENCY OF CARBONATE DISSOLUTION AND PRECIPITATION DURING DIAGENESIS: A PROGRESS REPORT ON THE ROLE OF SOLUTION CHEMISTRY",
    url = "https://doi.org/10.2475/ajs.274.2.108",
    doi = "10.2475/ajs.274.2.108",
    openalex = "W1986601587"
}

The temperature coefficient of the log Pco 2 ‐temperature relationship for springwater from carbonate terrains in North America is approximately 0.07/°C. Consideration of a simple model of soil air behavior and various published data suggests that the temperature coefficient of the same relationship for soil air is of the order of 0.04/°C. A model where the soil zone is the source of carbon dioxide for water entering a groundwater system and where the subsequent chemical evolution of the water occurs under closed system conditions is consistent with these relationships.

@article{doi101029wr011i006p00958,
    author = "Drake, John J. and Wigley, T. M. L.",
    title = "The effect of climate on the chemistry of carbonate groundwater",
    year = "1975",
    journal = "Water Resources Research",
    abstract = "The temperature coefficient of the log Pco 2 ‐temperature relationship for springwater from carbonate terrains in North America is approximately 0.07/°C. Consideration of a simple model of soil air behavior and various published data suggests that the temperature coefficient of the same relationship for soil air is of the order of 0.04/°C. A model where the soil zone is the source of carbon dioxide for water entering a groundwater system and where the subsequent chemical evolution of the water occurs under closed system conditions is consistent with these relationships.",
    url = "https://doi.org/10.1029/wr011i006p00958",
    doi = "10.1029/wr011i006p00958",
    openalex = "W2161033066"
}

@article{doi1010160022169479901781,
    author = "Stringfield, V. T. and Rapp, J.R. and Anders, Robert B.",
    title = "Effects of karst and geologic structure on the circulation of water and permeability in carbonate aquifers",
    year = "1979",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/0022-1694(79)90178-1",
    doi = "10.1016/0022-1694(79)90178-1",
    openalex = "W2070269122",
    references = "doi1010160016703771900196, doi1010160022169469900869, doi1010160022169470902222, doi1010160022169471900011, doi1010160022169471900035, doi1010160022169472901151, doi1011300016760619687919cahfit20co2, doi102134agronj195400021962004600080009x, doi1023071791828, doi103406geo195916541, openalexw2604877834, thrailkill1972carbonate"
}

The hydrological, thermal, and chemical characteristics of two small streams flowing through relatively undisturbed, low‐elevation mountain watersheds in southwestern British Columbia were investigated. All observations and chemical analyses of ecosystems were consistent with the hypothesis that stormflow originated mainly from flow of water through soil macrochannels to groundwater and thence to streams. Water budgets indicated unmeasured groundwater losses. The streams exhibited annual chemical cycles for most parameters, with maximum values in late summer and early autumn and minimum values in winter and early spring. Nitrate concentrations displayed no consistent seasonal variation, whereas potassium and sulphate concentrations were relatively uniform throughout the year. Most chemical parameters decreased with increasing discharge, whereas dissolved oxygen concentrations increased. Potassium concentrations exhibited some increases and some decreases, and chloride, nitrate, and sulphate concentrations were generally not significantly related to discharge. Concentration‐discharge relationships were used to infer the origin of stormflow water. Differences in the chemistry of the two very similar streams have important ramifications for the design of watershed nutrient studies. Nutrient budgets were very similar to those of other watersheds in humid temperate regions, with net losses of calcium, sodium, magnesium, potassium, chloride, and sulphur. Nitrogen and phosphorus exports in dissolved or particulate organic form were not measured. Based on dissolved inorganic measurements, nitrogen was accumulated, while any gains or losses of phosphorus were extremely small.

@article{doi101029wr015i002p00247,
    author = "Feller, M. and Kimmins, J. P.",
    title = "Chemical characteristics of small streams near Haney in southwestern British Columbia",
    year = "1979",
    journal = "Water Resources Research",
    abstract = "The hydrological, thermal, and chemical characteristics of two small streams flowing through relatively undisturbed, low‐elevation mountain watersheds in southwestern British Columbia were investigated. All observations and chemical analyses of ecosystems were consistent with the hypothesis that stormflow originated mainly from flow of water through soil macrochannels to groundwater and thence to streams. Water budgets indicated unmeasured groundwater losses. The streams exhibited annual chemical cycles for most parameters, with maximum values in late summer and early autumn and minimum values in winter and early spring. Nitrate concentrations displayed no consistent seasonal variation, whereas potassium and sulphate concentrations were relatively uniform throughout the year. Most chemical parameters decreased with increasing discharge, whereas dissolved oxygen concentrations increased. Potassium concentrations exhibited some increases and some decreases, and chloride, nitrate, and sulphate concentrations were generally not significantly related to discharge. Concentration‐discharge relationships were used to infer the origin of stormflow water. Differences in the chemistry of the two very similar streams have important ramifications for the design of watershed nutrient studies. Nutrient budgets were very similar to those of other watersheds in humid temperate regions, with net losses of calcium, sodium, magnesium, potassium, chloride, and sulphur. Nitrogen and phosphorus exports in dissolved or particulate organic form were not measured. Based on dissolved inorganic measurements, nitrogen was accumulated, while any gains or losses of phosphorus were extremely small.",
    url = "https://doi.org/10.1029/wr015i002p00247",
    doi = "10.1029/wr015i002p00247",
    openalex = "W2023131848",
    references = "doi1010079781461599937, doi1010160022169472901151, doi101029tr014i001p00446, doi101029wr005i006p01353, doi101029wr006i002p00478, doi101029wr006i004p01133, doi101029wr006i005p01296, doi101029wr008i005p01272, doi1023071933735, doi1023071942440, openalexw1554284265, thrailkill1972carbonate"
}

1. The Hydrologic Cycle. 2. Chemical Background. 3. Organic Compounds in Natural Waters. 4. The Carbonate System and pH Control. 5. Clay Minerals and Ion Exchange. 6. Stability Relationships and Silicate Equilibria. 7. Kinetics. 8. Weathering and Water Chemistry, I: Principles. 9. Weathering and Water Chemistry, II: Examples. 10. Acid Deposition and Surface Water Chemistry. 11. Evaporation and Saline Waters. 12. The Oceans. 13. Redox Equilibria. 14. Redox Conditions in Natural Waters. 15. Trace Elements. 16. Mathematical and Numerical Models. 17. Isotopes. Appendices.

@book{openalexw1591787667,
    author = "Drever, James I.",
    title = "Geochemistry of Natural Waters",
    year = "1982",
    abstract = "1. The Hydrologic Cycle. 2. Chemical Background. 3. Organic Compounds in Natural Waters. 4. The Carbonate System and pH Control. 5. Clay Minerals and Ion Exchange. 6. Stability Relationships and Silicate Equilibria. 7. Kinetics. 8. Weathering and Water Chemistry, I: Principles. 9. Weathering and Water Chemistry, II: Examples. 10. Acid Deposition and Surface Water Chemistry. 11. Evaporation and Saline Waters. 12. The Oceans. 13. Redox Equilibria. 14. Redox Conditions in Natural Waters. 15. Trace Elements. 16. Mathematical and Numerical Models. 17. Isotopes. Appendices.",
    openalex = "W1591787667"
}

Quantitative predictions of the effects of acid deposition onterrestrial and aquatic systems require physically based, process‐oriented models of catchment soil water and streamwater chemistry. A desirable characteristic of such models is that they include terms to describe the important phenomena controlling a system's chemical response to acidic deposition, yet be restricted in complexity so that they can be implemented on diverse systems with a minimum of a priori data. We present an assessment of a conceptual model of soil water and streamwater chemistry based on soil cation exchange, dissolution of aluminum hydroxide, and solution of carbon dioxide, all processes that occur in catchment soils and that have rapid equilibration times. The model is constructed using an “average” or lumped representation of these spatially distributed catchment processes. The adequacy of the model is assessed by applying it to 3 years of soil water and streamwater chemistry data from White Oak Run, Virginia, a second‐order stream in the Shenandoah National Park. Soil properties predicted by the model are in good agreement with presently available measurements of those soil properties. The success of the model suggests that lumped representations of complex and spatially distributed chemical reactions in soils can efficiently describe the gross chemical behavior of whole catchments (e.g., p H, alkalinity, and major ionic concentrations in surface waters). Further assessment of the adequacy of this conceptual approach will require more detailed empirical knowledge of the soil processes being modeled, particularly soil cation exchange and the variability of soil CO 2 partial pressures.

@article{doi101029wr021i001p00051,
    author = "Cosby, B. J. and Hornberger, George M. and Galloway, James N. and Wright, Richard F.",
    title = "Modeling the Effects of Acid Deposition: Assessment of a Lumped Parameter Model of Soil Water and Streamwater Chemistry",
    year = "1985",
    journal = "Water Resources Research",
    abstract = "Quantitative predictions of the effects of acid deposition onterrestrial and aquatic systems require physically based, process‐oriented models of catchment soil water and streamwater chemistry. A desirable characteristic of such models is that they include terms to describe the important phenomena controlling a system's chemical response to acidic deposition, yet be restricted in complexity so that they can be implemented on diverse systems with a minimum of a priori data. We present an assessment of a conceptual model of soil water and streamwater chemistry based on soil cation exchange, dissolution of aluminum hydroxide, and solution of carbon dioxide, all processes that occur in catchment soils and that have rapid equilibration times. The model is constructed using an “average” or lumped representation of these spatially distributed catchment processes. The adequacy of the model is assessed by applying it to 3 years of soil water and streamwater chemistry data from White Oak Run, Virginia, a second‐order stream in the Shenandoah National Park. Soil properties predicted by the model are in good agreement with presently available measurements of those soil properties. The success of the model suggests that lumped representations of complex and spatially distributed chemical reactions in soils can efficiently describe the gross chemical behavior of whole catchments (e.g., p H, alkalinity, and major ionic concentrations in surface waters). Further assessment of the adequacy of this conceptual approach will require more detailed empirical knowledge of the soil processes being modeled, particularly soil cation exchange and the variability of soil CO 2 partial pressures.",
    url = "https://doi.org/10.1029/wr021i001p00051",
    doi = "10.1029/wr021i001p00051",
    openalex = "W2083991228",
    references = "doi1010079781461344520, doi1010079781461567615, doi1010160016003250904364, doi1010160016703781902763, doi101021ja01250a059, doi101021ja01851a058, doi101038scientificamerican107943, doi10106311698996, doi101126science2214610520, galloway1983freshwater, openalexw1486416230"
}

@misc{crossref1988dye,
    title = "Dye tracing techniques used to determine ground-water flow in a carbonate aquifer system near Elizabethtown, Kentucky",
    year = "1988",
    url = "https://doi.org/10.3133/wri874174",
    doi = "10.3133/wri874174",
    openalex = "W98816013",
    references = "doi101001archderm196301590140145030, doi1010160022169471900801, doi101029wr013i001p00015, doi101061jsedai0000900, doi10108000224065198311978863, doi1013023kwrrirr136, doi1023071788077, doi1023072988312, openalexw1574188141, openalexw2799217134"
}

@article{doi1010160022169488900510,
    author = "Hess, Jonn W. and White, William B.",
    title = "Storm response of the karstic carbonate aquifer of southcentral Kentucky",
    year = "1988",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/0022-1694(88)90051-0",
    doi = "10.1016/0022-1694(88)90051-0",
    openalex = "W1997197351",
    references = "doi102307213346"
}

EPA 904/6-88-001 "Prepared by U.S. Environmental Protection Agency, Ground-Water Protection Branch, Region IV, Atlanta, Georgia and U.S. Geological Survey, Water Resources Division, Kentucky District, Louisville, Kentucky. 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. I am please to announce that these efforts have resulted in the preparation of this manual, entitled, "Application of Dye-Tracing Techniques for Determining Solute-Transport Characteristics of Ground Water in Karst Terranes." The information presented herein should be viewed as another analytical "tool" in the management and protection of karst water supplies...." Open Access - Permission by Publisher See Extended description for more information.

@article{openalexw1583262885,
    author = "Mull, D.S. and Liebermann, Timothy D. and Smoot, J.L. and Woosley, L.H.",
    title = "Application of dye-tracing techniques for determining solute-transport characteristics of ground water in karst terranes",
    year = "1988",
    journal = "Digital Commons - University of South Florida (University of South Florida)",
    abstract = {EPA 904/6-88-001 "Prepared by U.S. Environmental Protection Agency, Ground-Water Protection Branch, Region IV, Atlanta, Georgia and U.S. Geological Survey, Water Resources Division, Kentucky District, Louisville, Kentucky. 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. I am please to announce that these efforts have resulted in the preparation of this manual, entitled, "Application of Dye-Tracing Techniques for Determining Solute-Transport Characteristics of Ground Water in Karst Terranes." The information presented herein should be viewed as another analytical "tool" in the management and protection of karst water supplies...." Open Access - Permission by Publisher See Extended description for more information.},
    openalex = "W1583262885",
    references = "crossref1988dye"
}

Large fluctuations in Ca and Mg concentrations occur in the discharge of karst springs in southeastern Missouri after major storm events. Rapid flow of relatively dilute, storm‐derived water through solution conduits in the aquifer causes the fluctuations in chemistry. A cation balance for the discharge of one spring indicates that about 25% of the total spring flow is storm‐derived water. These storm‐derived contributions reach a maximum during the recession of storm responses in the spring flow hydrograph. At the peak of the responses, spring flow is composed primarily of prestorm water that has been displaced in the conduit system by the storm‐derived water. The observed chemical fluctuations and hydrograph components differ from those observed in streamflow where the time of the maximum dilution usually coincides with the time of peak discharge.

@article{doi101029wr025i001p00117,
    author = "Dreiss, Shirley J.",
    title = "Regional scale transport in a Karst Aquifer: 1. Component separation of spring flow hydrographs",
    year = "1989",
    journal = "Water Resources Research",
    abstract = "Large fluctuations in Ca and Mg concentrations occur in the discharge of karst springs in southeastern Missouri after major storm events. Rapid flow of relatively dilute, storm‐derived water through solution conduits in the aquifer causes the fluctuations in chemistry. A cation balance for the discharge of one spring indicates that about 25\% of the total spring flow is storm‐derived water. These storm‐derived contributions reach a maximum during the recession of storm responses in the spring flow hydrograph. At the peak of the responses, spring flow is composed primarily of prestorm water that has been displaced in the conduit system by the storm‐derived water. The observed chemical fluctuations and hydrograph components differ from those observed in streamflow where the time of the maximum dilution usually coincides with the time of peak discharge.",
    url = "https://doi.org/10.1029/wr025i001p00117",
    doi = "10.1029/wr025i001p00117",
    openalex = "W2023742089"
}

Travel time distributions of water or tracers in conduit‐type karst aquifers can be found from linear systems analysis of either tracer test data or naturally occurring fluctuations in springflow chemistry. I use the chemical fluctuations at Maramec Spring, Missouri described in paper 1 (Dreiss, this issue) and results from a previous tracer test to derive a set of kernal functions that represent regional scale transport in the karst conduit network. A single kernel is sufficient to simulate the storm‐derived component of Maramec springflow, suggesting that rapid transport in the conduit network is well‐approximated by temporal stationarity. Time moment analysis of the kernels leads to several conclusions. The kernel for the tracer test exhibits a larger mean residence time and much smaller variance than the kernels derived from nonpoint source recharge. Thus the tracer travel distance appears to be longer than the mean travel distance of rapid recharge and much of the variance of nonpoint source kernels apparently results from the distribution of flow path lengths to the spring. By assuming an effective transport model and comparing the moments of the empirical tracer test kernel to the moments of the impulse response of the model, I compute an effective velocity between the tracer input point and Maramec Spring of 1.3 km/day and an effective dispersivity of 0.29 km. Because the time moments of the kernels and the effective transport parameters can be computed from readily measured springflow properties, they may prove to be a convenient means for studying and comparing regional scale transport in karst aquifers.

@article{doi101029wr025i001p00126,
    author = "Dreiss, Shirley J.",
    title = "Regional scale transport in a Karst Aquifer: 2. Linear systems and time moment analysis",
    year = "1989",
    journal = "Water Resources Research",
    abstract = "Travel time distributions of water or tracers in conduit‐type karst aquifers can be found from linear systems analysis of either tracer test data or naturally occurring fluctuations in springflow chemistry. I use the chemical fluctuations at Maramec Spring, Missouri described in paper 1 (Dreiss, this issue) and results from a previous tracer test to derive a set of kernal functions that represent regional scale transport in the karst conduit network. A single kernel is sufficient to simulate the storm‐derived component of Maramec springflow, suggesting that rapid transport in the conduit network is well‐approximated by temporal stationarity. Time moment analysis of the kernels leads to several conclusions. The kernel for the tracer test exhibits a larger mean residence time and much smaller variance than the kernels derived from nonpoint source recharge. Thus the tracer travel distance appears to be longer than the mean travel distance of rapid recharge and much of the variance of nonpoint source kernels apparently results from the distribution of flow path lengths to the spring. By assuming an effective transport model and comparing the moments of the empirical tracer test kernel to the moments of the impulse response of the model, I compute an effective velocity between the tracer input point and Maramec Spring of 1.3 km/day and an effective dispersivity of 0.29 km. Because the time moments of the kernels and the effective transport parameters can be computed from readily measured springflow properties, they may prove to be a convenient means for studying and comparing regional scale transport in karst aquifers.",
    url = "https://doi.org/10.1029/wr025i001p00126",
    doi = "10.1029/wr025i001p00126",
    openalex = "W2017947580"
}

Stable isotope data for dissolved carbonate, sulfate, and sulfide are combined with water composition data to construct geochemical reaction models along eight flow paths in the Madison aquifer in parts of Wyoming, Montana, and South Dakota. The sulfur isotope data are treated as an isotope dilution problem, whereas the carbon isotope data are treated as Rayleigh distillations. All reaction models reproduce the observed chemical and carbon and sulfur isotopic composition of the final waters and are partially validated by predicting the observed carbon and sulfur isotopic compositions of dolomite and anhydrite from the Madison Limestone. The geochemical reaction models indicate that the dominant groundwater reaction in the Madison aquifer is dedolomitization (calcite precipitation and dolomite dissolution driven by anhydrite dissolution). Sulfate reduction, [Ca 2+ + Mg 2+]/Na + cation exchange, and halite dissolution are locally important, particularly in central Montana. The groundwater system is treated as closed to CO 2 gas from external sources such as the soil zone or cross‐formational leakage but open to CO 2 from oxidation of organic matter coupled with sulfate reduction and other redox processes occurring within the aquifer. The computed mineral mass transfers and modeled sulfur isotopic composition of Madison anhydrites are mapped throughout the study area. Carbon 14 groundwater ages, adjusted for the modeled carbon mass transfer, range from modern to about 23,000 years B.P. and indicate flow velocities of 7–87 ft/yr (2.1–26.5 m/yr). Most horizontal hydraulic conductivities calculated from Darcy's Law using the average 14 C flow velocities are within a factor of 5 of those based on digital simulation. The calculated mineral mass transfer and adjusted 14 C groundwater ages permit determination of apparent rates of reaction in the aquifer. The apparent rate of organic matter oxidation is typically 0.12 μmol/L/yr. Sulfate and, to a lesser extent, ferric iron are the predominant electron acceptors. The (kinetic) biochemical fractionation of 34 S between sulfate and hydrogen sulfide is approximately −44‰ at 25°C, with a temperature variation of −0.4‰ per °C. The rates of precipitation of calcite and dissolution of dolomite and anhydrite typically are 0.59, 0.24, and 0.95 μmol/L/yr, respectively.

@article{doi101029wr026i009p01981,
    author = "Plummer, L. Niel and Busby, John F. and Lee, Roger W. and Hanshaw, Bruce B.",
    title = "Geochemical Modeling of the Madison Aquifer in Parts of Montana, Wyoming, and South Dakota",
    year = "1990",
    journal = "Water Resources Research",
    abstract = "Stable isotope data for dissolved carbonate, sulfate, and sulfide are combined with water composition data to construct geochemical reaction models along eight flow paths in the Madison aquifer in parts of Wyoming, Montana, and South Dakota. The sulfur isotope data are treated as an isotope dilution problem, whereas the carbon isotope data are treated as Rayleigh distillations. All reaction models reproduce the observed chemical and carbon and sulfur isotopic composition of the final waters and are partially validated by predicting the observed carbon and sulfur isotopic compositions of dolomite and anhydrite from the Madison Limestone. The geochemical reaction models indicate that the dominant groundwater reaction in the Madison aquifer is dedolomitization (calcite precipitation and dolomite dissolution driven by anhydrite dissolution). Sulfate reduction, [Ca 2+ + Mg 2+]/Na + cation exchange, and halite dissolution are locally important, particularly in central Montana. The groundwater system is treated as closed to CO 2 gas from external sources such as the soil zone or cross‐formational leakage but open to CO 2 from oxidation of organic matter coupled with sulfate reduction and other redox processes occurring within the aquifer. The computed mineral mass transfers and modeled sulfur isotopic composition of Madison anhydrites are mapped throughout the study area. Carbon 14 groundwater ages, adjusted for the modeled carbon mass transfer, range from modern to about 23,000 years B.P. and indicate flow velocities of 7–87 ft/yr (2.1–26.5 m/yr). Most horizontal hydraulic conductivities calculated from Darcy's Law using the average 14 C flow velocities are within a factor of 5 of those based on digital simulation. The calculated mineral mass transfer and adjusted 14 C groundwater ages permit determination of apparent rates of reaction in the aquifer. The apparent rate of organic matter oxidation is typically 0.12 μmol/L/yr. Sulfate and, to a lesser extent, ferric iron are the predominant electron acceptors. The (kinetic) biochemical fractionation of 34 S between sulfate and hydrogen sulfide is approximately −44‰ at 25°C, with a temperature variation of −0.4‰ per °C. The rates of precipitation of calcite and dissolution of dolomite and anhydrite typically are 0.59, 0.24, and 0.95 μmol/L/yr, respectively.",
    url = "https://doi.org/10.1029/wr026i009p01981",
    doi = "10.1029/wr026i009p01981",
    openalex = "W2095065076"
}

To model the development of karst aquifers from primary fissures in limestone rock, a numerical model of solutional widening of such fractures by calcite agressive water is suggested. The geological setting determines relevant geometrical parameters, i.e., length of the fracture, its initial width and the hydraulic gradient driving water from the input to the output. To simulate the solutional widening as it proceeds in time, the solution rates must be known as a function of concentration c of dissolved calcite. They are given as a first-order kinetic rate law for $$c \leq k \cdot c_{eq}$$ as $$F^{(1)} = \alpha_{0}(c - c_{eq}$$. For $$c > k \cdot c_{eq}$$ close to equilibrium, a fourth-order rate law becomes dominant: $$F^{(4)} = \beta \cdot (c - c_{eq})^{4}$$. The parameters $$\alpha_{0}, \beta$$, and k depend on the chemistry of the carbonate system and rock chemistry. The saturation concentration, c_{eq}, with respect to calcite depends on the initial $$CO_{2}$$ concentration of the inflowing solution, thus reflecting the influence of climate. The value of k for natural limestone ranges between 0.5 and 0.9. The results of the model show that the concerted action of both fast first-order kinetics and slow fourth-order kinetics is necessary to create early karst channels of several cm width in geologically reasonable times. At the beginning of the process the solutional widening occurs by slow fourth-order kinetics along the entire length of the fracture, because water reaches sufficiently high concentrations less than 1 m from the input. This widens the fissure slowly. As a consequence, increasing water flow rate increases the distance where first-order kinetics are operative. This region propagates through the length of the fracture with accelerating speed until it reaches the outlet. At the moment of breakthrough the flow rate increases dramatically by several orders of magnitude. From then on, further solutional widening is essentially constant along the entire length of the fracture, on the order of about $$10^{-2}cm/yr$$. The breakthrough time is a significant measure in studies of karstification and has been calculated for a wide range of geometrical parameters. Expressions for its dependence on length, initial widths, and hydraulic gradient are derived, which allow ready calculation of breakthrough times for most realistic cases. Dependence of breakthrough times on chemical parameters reflects influences of lithology and climate. The lithologic parameters $$\alpha_{0}, \beta,$$, and k show only a small influence, which explains why karst features exist in so many different types of limestone. The dependence on $$c_{eq}$$ shows that karstification proceeds only at sufficiently high levels of $$CO_{2}$$ in the water entering the system. The model is applied to estimate evolution times of real karst aquifers in Germany, yielding results in agreement with geological observations. Depending on the geometrical parameters, especially length and hydraulic gradient, breakthrough times range from $$10^{4}$$ to several $$10^{6}$$ yr. The model is also applied to small-scale karst features, such as the evolution of solution dolines. In these cases fracture lengths are in the order of several tens of meters, and hydraulic gradients are high. This is also the case in land use projects where the groundwater table is lowered or artificial canals or dams are constructed. Karstification times of several tens to several hundred years are derived for these cases.

@article{doi101086629431,
    author = "Dreybrodt, Wolfgang",
    title = "The Role of Dissolution Kinetics in the Development of Karst Aquifers in Limestone: A Model Simulation of Karst Evolution",
    year = "1990",
    journal = "The Journal of Geology",
    abstract = "To model the development of karst aquifers from primary fissures in limestone rock, a numerical model of solutional widening of such fractures by calcite agressive water is suggested. The geological setting determines relevant geometrical parameters, i.e., length of the fracture, its initial width and the hydraulic gradient driving water from the input to the output. To simulate the solutional widening as it proceeds in time, the solution rates must be known as a function of concentration c of dissolved calcite. They are given as a first-order kinetic rate law for $$c \leq k \cdot c\_{eq}$$ as $$F^{(1)} = \alpha\_{0}(c - c\_{eq}$$. For $$c > k \cdot c\_{eq}$$ close to equilibrium, a fourth-order rate law becomes dominant: $$F^{(4)} = \beta \cdot (c - c\_{eq})^{4}$$. The parameters $$\alpha\_{0}, \beta$$, and k depend on the chemistry of the carbonate system and rock chemistry. The saturation concentration, c\_{eq}, with respect to calcite depends on the initial $$CO\_{2}$$ concentration of the inflowing solution, thus reflecting the influence of climate. The value of k for natural limestone ranges between 0.5 and 0.9. The results of the model show that the concerted action of both fast first-order kinetics and slow fourth-order kinetics is necessary to create early karst channels of several cm width in geologically reasonable times. At the beginning of the process the solutional widening occurs by slow fourth-order kinetics along the entire length of the fracture, because water reaches sufficiently high concentrations less than 1 m from the input. This widens the fissure slowly. As a consequence, increasing water flow rate increases the distance where first-order kinetics are operative. This region propagates through the length of the fracture with accelerating speed until it reaches the outlet. At the moment of breakthrough the flow rate increases dramatically by several orders of magnitude. From then on, further solutional widening is essentially constant along the entire length of the fracture, on the order of about $$10^{-2}cm/yr$$. The breakthrough time is a significant measure in studies of karstification and has been calculated for a wide range of geometrical parameters. Expressions for its dependence on length, initial widths, and hydraulic gradient are derived, which allow ready calculation of breakthrough times for most realistic cases. Dependence of breakthrough times on chemical parameters reflects influences of lithology and climate. The lithologic parameters $$\alpha\_{0}, \beta,$$, and k show only a small influence, which explains why karst features exist in so many different types of limestone. The dependence on $$c\_{eq}$$ shows that karstification proceeds only at sufficiently high levels of $$CO\_{2}$$ in the water entering the system. The model is applied to estimate evolution times of real karst aquifers in Germany, yielding results in agreement with geological observations. Depending on the geometrical parameters, especially length and hydraulic gradient, breakthrough times range from $$10^{4}$$ to several $$10^{6}$$ yr. The model is also applied to small-scale karst features, such as the evolution of solution dolines. In these cases fracture lengths are in the order of several tens of meters, and hydraulic gradients are high. This is also the case in land use projects where the groundwater table is lowered or artificial canals or dams are constructed. Karstification times of several tens to several hundred years are derived for these cases.",
    url = "https://doi.org/10.1086/629431",
    doi = "10.1086/629431",
    openalex = "W2064849586"
}

@article{doi101016002216949190046k,
    author = "Thrailkill, John and Sullivan, Stephen B. and Gouzie, Douglas",
    title = "Flow parameters in a shallow conduit-flow carbonate aquifer, Inner Bluegrass Karst Region, Kentucky, USA",
    year = "1991",
    journal = "Journal of Hydrology",
    url = "https://doi.org/10.1016/0022-1694(91)90046-k",
    doi = "10.1016/0022-1694(91)90046-k",
    openalex = "W1971754509",
    references = "crossref1988dye"
}

@article{doi101016088329279390034e,
    author = "Hess, John W. and White, William B.",
    title = "Groundwater geochemistry of the carbonate karst aquifer, southcentral Kentucky, U.S.A.",
    year = "1993",
    journal = "Applied Geochemistry",
    url = "https://doi.org/10.1016/0883-2927(93)90034-e",
    doi = "10.1016/0883-2927(93)90034-e",
    openalex = "W1994769063",
    references = "doi1010160016703782900564, doi1010160022169472901151, doi1010160022169477900798, doi1010160022169488900510, doi1010160304420383900415, doi101021bk19790093, doi101021bk19790093ch025, doi101086629431, doi102307213346, doi102475ajs2742108, doi105860choice262715, openalexw1591787667, thrailkill1972carbonate"
}

Abstract Although the charge balance for a single chemical analysis of a water's electrolytes is not a reliable gauge for the accuracy of that analysis, the percent charge‐balance error (%CBE) becomes more credible as a means for evaluating analytical technique when applied to groups of analyses. Just how good are charge balances for chemical analyses of potable ground and stream waters in mainline geological journals? Starting with each journal's first volume, a search found 68 articles in six journals (Appl. Geochem., Chem. Geol, Geochim. Cos. Acta., Ground Water, J. Hydrol, and Water Resources Res.) that had what was deemed to be “complete” analyses of individual samples' major ions. Analyses of brines and hydrothermal solutions were excluded as were “composite” averages. A total of 1,062 %CBEs were computed and tabulated, and the average was 3.99%$ 6.56 (1σ). The average %CBE (by journals) ranges from 1.55% to 9.34%. Quality of %CBE is slightly better for articles published after 1970. Not surprisingly, low ionic strength samples are prone to charge‐balance errors > 10%. Of the 1,062 charge balances calculated, 612 were positive and 450 were negative. Eight of the 68 articles had analyses that were evenly balanced between positive and negative CB errors. There are 21 articles in which the majority of analyses had negative charge‐balance errors. Thus a clear majority (39) of articles had analyses in which there were more positive than negative charge‐balance errors. Systematic error is likely for situations where the analyses in an article are predominantly positive or predominantly negative. The likely reason for the former occurrence is lab determination of alkalinity from the nonacidified field aliquot. Failure to filter samples may cause the latter situation—especially in carbonate terranes. Systematic laboratory errors involving salt standards and dilutions can also yield charge‐balance errors for a suite of analyses that are skewed to either positive or negative errors. The care with which the analyst did his/her job may also impact charge‐balance errors.

@article{doi101111j174565841994tb00888x,
    author = "Fritz, S.",
    title = "A Survey of Charge‐Balance Errors on Published Analyses of Potable Ground and Surface Waters",
    year = "1994",
    journal = "Ground Water",
    abstract = "Abstract Although the charge balance for a single chemical analysis of a water's electrolytes is not a reliable gauge for the accuracy of that analysis, the percent charge‐balance error (\%CBE) becomes more credible as a means for evaluating analytical technique when applied to groups of analyses. Just how good are charge balances for chemical analyses of potable ground and stream waters in mainline geological journals? Starting with each journal's first volume, a search found 68 articles in six journals (Appl. Geochem., Chem. Geol, Geochim. Cos. Acta., Ground Water, J. Hydrol, and Water Resources Res.) that had what was deemed to be “complete” analyses of individual samples' major ions. Analyses of brines and hydrothermal solutions were excluded as were “composite” averages. A total of 1,062 \%CBEs were computed and tabulated, and the average was 3.99\%$ 6.56 (1σ). The average \%CBE (by journals) ranges from 1.55\% to 9.34\%. Quality of \%CBE is slightly better for articles published after 1970. Not surprisingly, low ionic strength samples are prone to charge‐balance errors > 10\%. Of the 1,062 charge balances calculated, 612 were positive and 450 were negative. Eight of the 68 articles had analyses that were evenly balanced between positive and negative CB errors. There are 21 articles in which the majority of analyses had negative charge‐balance errors. Thus a clear majority (39) of articles had analyses in which there were more positive than negative charge‐balance errors. Systematic error is likely for situations where the analyses in an article are predominantly positive or predominantly negative. The likely reason for the former occurrence is lab determination of alkalinity from the nonacidified field aliquot. Failure to filter samples may cause the latter situation—especially in carbonate terranes. Systematic laboratory errors involving salt standards and dilutions can also yield charge‐balance errors for a suite of analyses that are skewed to either positive or negative errors. The care with which the analyst did his/her job may also impact charge‐balance errors.",
    url = "https://doi.org/10.1111/j.1745-6584.1994.tb00888.x",
    doi = "10.1111/j.1745-6584.1994.tb00888.x",
    openalex = "W2017086444",
    references = "doi101029wr015i002p00247"
}

1. Landscape characteristics of sixty‐two subcatchments within the Saginaw Bay Catchment of central Michigan were examined to identify relationships with stream water chemistry. Land use, land cover and elevation were quantified for both entire catchments and the upland–river ecotone (100 m stream buffer strip). Catchment and ecotone data were then empirically compared with stream water chemistry using multivariate and regression analyses. Redundancy analysis was used to partition variance among land use, geology, and the shared influence of land use and geology. 2. Major catchments dominated by rowcrop agriculture had the highest alkalinity, total dissolved solids and nitrate + nitrite concentrations. 3. Strong seasonal differences were observed in total nitrogen and nitrite + nitrate, but not in total phosphorus or suspended solids. Land use and landscape structure factors such as slope and patch density (number of land use patches per km 2) accounted for most of the observed variance in summer. 4. In both autumn and summer, landscape factors accounted for much of the observed variation in total dissolved solids and alkalinity. During autumn, geological factors and the shared influence of geology/landscape structure plus land use exerted more influence than did land use alone. 5. Total phosphorus and total suspended solids were much better explained by land use within the stream ecotone in summer than in other seasons. However, total nitrogen, nitrate, orthophosphate and alkalinity were equally well explained by land use within the ecotone and throughout the whole catchment. Only total dissolved solids in summer and ammonium in autumn were explained better by the whole catchment than the ecotone. 6. Our results show that relatively coarse spatial databases can provide useful descriptors of regional water quality.

@article{doi101046j136524271997d01539x,
    author = "Johnson, Lucinda B. and Richards, Carl and Host, George E. and Arthur, John",
    title = "Landscape influences on water chemistry in Midwestern stream ecosystems",
    year = "1997",
    journal = "Freshwater Biology",
    abstract = "1. Landscape characteristics of sixty‐two subcatchments within the Saginaw Bay Catchment of central Michigan were examined to identify relationships with stream water chemistry. Land use, land cover and elevation were quantified for both entire catchments and the upland–river ecotone (100 m stream buffer strip). Catchment and ecotone data were then empirically compared with stream water chemistry using multivariate and regression analyses. Redundancy analysis was used to partition variance among land use, geology, and the shared influence of land use and geology. 2. Major catchments dominated by rowcrop agriculture had the highest alkalinity, total dissolved solids and nitrate + nitrite concentrations. 3. Strong seasonal differences were observed in total nitrogen and nitrite + nitrate, but not in total phosphorus or suspended solids. Land use and landscape structure factors such as slope and patch density (number of land use patches per km 2) accounted for most of the observed variance in summer. 4. In both autumn and summer, landscape factors accounted for much of the observed variation in total dissolved solids and alkalinity. During autumn, geological factors and the shared influence of geology/landscape structure plus land use exerted more influence than did land use alone. 5. Total phosphorus and total suspended solids were much better explained by land use within the stream ecotone in summer than in other seasons. However, total nitrogen, nitrate, orthophosphate and alkalinity were equally well explained by land use within the ecotone and throughout the whole catchment. Only total dissolved solids in summer and ammonium in autumn were explained better by the whole catchment than the ecotone. 6. Our results show that relatively coarse spatial databases can provide useful descriptors of regional water quality.",
    url = "https://doi.org/10.1046/j.1365-2427.1997.d01-539.x",
    doi = "10.1046/j.1365-2427.1997.d01-539.x",
    openalex = "W2169749005"
}

Abstract In the mantled karst terrane of northern Florida, the water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface. Chemical and isotopic analyses [18 O/ 16 O (δ 18 O), 2 H/ 1 H (δD), 13 C/ 12 C (δ 13 C), tritium (3 H), and strontium‐87/strontium‐86 (87 Sr/ 86 Sr)] along with geochemical mass‐balance modeling were used to identify the dominant hydrochemical processes that control the composition of ground water as it evolves downgradient in two systems. In one system, surface water enters the Upper Floridan aquifer through a sinkhole located in the Northern Highlands physiographic unit. In the other system, surface water enters the aquifer through a sinkhole lake (Lake Bradford) in the Woodville Karst Plain. Differences in the composition of water isotopes (δ 18 O and <δD) in rainfall, ground water, and surface water were used to develop mixing models of surface water (leakage of water to the Upper Floridan aquifer from a sinkhole lake and a sinkhole) and ground water. Using mass‐balance calculations, based on differences in δ 18 O and δD, the proportion of lake water that mixed with meteoric water ranged from 7 to 86% in water from wells located in close proximity to Lake Bradford. In deeper parts of the Upper Floridan aquifer, water enriched in 18 O and D from five of 12 sampled municipal wells indicated that recharge from a sinkhole (1 to 24%) and surface water with an evaporated isotopic signature (2 to 32%) was mixing with ground water. The solute isotopes, δ 13 C and 87 Sr/ 86 Sr, were used to test the sensitivity of binary and ternary mixing models, and to estimate the amount of mass transfer of carbon and other dissolved species in geochemical reactions. In ground water downgradient from Lake Bradford, the dominant processes controlling carbon cycling in ground water were dissolution of carbonate minerals, aerobic degradation of organic matter, and hydrolysis of silicate minerals. In the deeper parts of the Upper Floridan aquifer, the major processes controlling the concentrations of major dissolved species included dissolution of calcite and dolomite, and degradation of organic matter under oxic conditions. The Upper Floridan aquifer is highly susceptible to contamination from activities at the land surface in the Tallahassee area. The presence of post‐ 1950s concentrations of 3 H in ground water from depths greater than 100 m below land surface indicates that water throughout much of the Upper Floridan aquifer has been recharged during the last 40 years. Even though mixing is likely between ground water and surface water in many parts of the study area, the Upper Floridan aquifer produces good quality water, which due to dilution effects shows little if any impact from trace elements or nutrients that are present in surface waters.

@article{doi101111j174565841997tb00174x,
    author = "Katz, Brian G. and Coplen, Tyler B. and Bullen, Thomas D. and Davis, J. Hal",
    title = "Use of Chemical and Isotopic Tracers to Characterize the Interactions Between Ground Water and Surface Water in Mantled Karst",
    year = "1997",
    journal = "Ground Water",
    abstract = "Abstract In the mantled karst terrane of northern Florida, the water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface. Chemical and isotopic analyses [18 O/ 16 O (δ 18 O), 2 H/ 1 H (δD), 13 C/ 12 C (δ 13 C), tritium (3 H), and strontium‐87/strontium‐86 (87 Sr/ 86 Sr)] along with geochemical mass‐balance modeling were used to identify the dominant hydrochemical processes that control the composition of ground water as it evolves downgradient in two systems. In one system, surface water enters the Upper Floridan aquifer through a sinkhole located in the Northern Highlands physiographic unit. In the other system, surface water enters the aquifer through a sinkhole lake (Lake Bradford) in the Woodville Karst Plain. Differences in the composition of water isotopes (δ 18 O and <δD) in rainfall, ground water, and surface water were used to develop mixing models of surface water (leakage of water to the Upper Floridan aquifer from a sinkhole lake and a sinkhole) and ground water. Using mass‐balance calculations, based on differences in δ 18 O and δD, the proportion of lake water that mixed with meteoric water ranged from 7 to 86\% in water from wells located in close proximity to Lake Bradford. In deeper parts of the Upper Floridan aquifer, water enriched in 18 O and D from five of 12 sampled municipal wells indicated that recharge from a sinkhole (1 to 24\%) and surface water with an evaporated isotopic signature (2 to 32\%) was mixing with ground water. The solute isotopes, δ 13 C and 87 Sr/ 86 Sr, were used to test the sensitivity of binary and ternary mixing models, and to estimate the amount of mass transfer of carbon and other dissolved species in geochemical reactions. In ground water downgradient from Lake Bradford, the dominant processes controlling carbon cycling in ground water were dissolution of carbonate minerals, aerobic degradation of organic matter, and hydrolysis of silicate minerals. In the deeper parts of the Upper Floridan aquifer, the major processes controlling the concentrations of major dissolved species included dissolution of calcite and dolomite, and degradation of organic matter under oxic conditions. The Upper Floridan aquifer is highly susceptible to contamination from activities at the land surface in the Tallahassee area. The presence of post‐ 1950s concentrations of 3 H in ground water from depths greater than 100 m below land surface indicates that water throughout much of the Upper Floridan aquifer has been recharged during the last 40 years. Even though mixing is likely between ground water and surface water in many parts of the study area, the Upper Floridan aquifer produces good quality water, which due to dilution effects shows little if any impact from trace elements or nutrients that are present in surface waters.",
    url = "https://doi.org/10.1111/j.1745-6584.1997.tb00174.x",
    doi = "10.1111/j.1745-6584.1997.tb00174.x",
    openalex = "W2048699439",
    references = "doi101021bk19790093ch038"
}

Many active stream conduits within karst aquifers transport and deposit non-carbonate, clastic sediment. However, little is known about how these sediments impact conduit development and enlargement rates. For example, can dissolution take place at the sediment/bedrock interface beneath a flowing stream? If not, cavern enlargement might be dominated by flood conditions when the bare rock of the walls and ceiling are in contact with the dissolving fluids. An approach using limestone tablet weight loss experiments, along with water sampling and geochemical modeling, has been undertaken to understand the nature of fluid movement and chemistry with the sediment beneath an active flowing cave stream within the Kentucky's Mammoth Cave System. Fluid flow and carbonate chemistry were compared between the active stream and within the sediment at 15, 30, 60, and 90 cm below the stream bed. It was found that carbon dioxide pressure within the interstitial fluids was elevated an order of magnitude above that of the stream waters, having levels as much as 31 times that of atmospheric background, presumably from microbial decomposition of organic material. The fluids were all under-saturated with respect to calcite (SI= -0.4 to -0.9), and limestone blocks buried at these levels all dissolved (rates from 0.8 to 21.9 g m -2 yr -1). These results suggest that at some locations the limestone bedrock may be dissolving beneath clastic sediment deposits; which in turn has implications for understanding rates and geometries of conduit evolution within karst aquifers.

@article{s21458ea3101b8f573b43cd9650370d05feaea144e,
    author = "Vaughan, K.",
    title = "A Quantitative Analysis of Interstitial Fluid-Chemistry and Limestone Dissolution Rates Within the Clastic Sediment of a Karst Aquifer Conduit, Mammoth Cave, Kentucky",
    year = "1998",
    journal = "TopSCHOLAR (Western Kentucky University)",
    abstract = "Many active stream conduits within karst aquifers transport and deposit non-carbonate, clastic sediment. However, little is known about how these sediments impact conduit development and enlargement rates. For example, can dissolution take place at the sediment/bedrock interface beneath a flowing stream? If not, cavern enlargement might be dominated by flood conditions when the bare rock of the walls and ceiling are in contact with the dissolving fluids. An approach using limestone tablet weight loss experiments, along with water sampling and geochemical modeling, has been undertaken to understand the nature of fluid movement and chemistry with the sediment beneath an active flowing cave stream within the Kentucky's Mammoth Cave System. Fluid flow and carbonate chemistry were compared between the active stream and within the sediment at 15, 30, 60, and 90 cm below the stream bed. It was found that carbon dioxide pressure within the interstitial fluids was elevated an order of magnitude above that of the stream waters, having levels as much as 31 times that of atmospheric background, presumably from microbial decomposition of organic material. The fluids were all under-saturated with respect to calcite (SI= -0.4 to -0.9), and limestone blocks buried at these levels all dissolved (rates from 0.8 to 21.9 g m -2 yr -1). These results suggest that at some locations the limestone bedrock may be dissolving beneath clastic sediment deposits; which in turn has implications for understanding rates and geometries of conduit evolution within karst aquifers.",
    url = "https://www.semanticscholar.org/paper/1458ea3101b8f573b43cd9650370d05feaea144e",
    is_oa = "true",
    openalex = "W206068069",
    semanticscholar_citation_count = "6",
    semanticscholar_id = "1458ea3101b8f573b43cd9650370d05feaea144e"
}

@misc{crossref2002hydrogeologic,
    title = "Hydrogeologic framework and geochemistry of ground water and petroleum in the Silurian-Devonian carbonate aquifer, south-central Louisville, Kentucky",
    year = "2002",
    url = "https://doi.org/10.3133/wri024123",
    doi = "10.3133/wri024123",
    openalex = "W1552168360",
    references = "doi1010160025326x8390320x, doi101016014663809290041u, doi10102998eo00453, doi101029wr003i001p00263, doi101126science13334651702, doi101306m35439c7, doi101306m51530c25, doi101306m51530c27"
}

This paper is intended to provide insight into the controlling mechanisms of karst genesis based on an advanced modeling approach covering the characteristic hydraulics in karst systems, the dissolution kinetics, and the associated temporal decrease in flow resistance. Karst water hydraulics is strongly governed by the interaction between a highly conductive low storage conduit network and a low‐conductive high‐storage rock matrix under variable boundary conditions. Only if this coupling of flow mechanisms is considered can an appropriate representation of other relevant processes be achieved, e.g., carbonate dissolution, transport of dissolved solids, and limited groundwater recharge. Here a parameter study performed with the numerical model Carbonate Aquifer Void Evolution (CAVE) is presented, which allows the simulation of the genesis of karst aquifers during geologic time periods. CAVE integrates several important features relevant for different scenarios of karst evolution: (1) the complex hydraulic interplay between flow in the karst conduits and in the small fissures of the rock matrix, (2) laminar as well as turbulent flow conditions, (3) time‐dependent and nonuniform recharge to both flow systems, (4) the widening of the conduits accounting for appropriate physicochemical relationships governing calcite dissolution kinetics. This is achieved by predefining an initial network of karst conduits (“protoconduits”) which are allowed to grow according to the amount of aggressive water available due to hydraulic boundary conditions. The increase in conduit transmissivity is associated with an increase in conduit diameters while the conductivity of the fissured system is assumed to be constant in time. The importance of various parameters controlling karst genesis is demonstrated in a parameter study covering the recharge distribution, the upgradient boundary conditions for the conduit system, and the hydraulic coupling between the conduit network and the rock matrix. In particular, it is shown that conduit diameters increase in downgradient or upgradient direction depending on the spatial distribution (local versus uniform) of the recharge component which directly enters the conduit system.

@article{doi1010292001wr001206,
    author = "Liedl, Rudolf and Sauter, Martin and Hückinghaus, Dirk and Clemens, Torsten and Teutsch, Georg",
    title = "Simulation of the development of karst aquifers using a coupled continuum pipe flow model",
    year = "2003",
    journal = "Water Resources Research",
    abstract = "This paper is intended to provide insight into the controlling mechanisms of karst genesis based on an advanced modeling approach covering the characteristic hydraulics in karst systems, the dissolution kinetics, and the associated temporal decrease in flow resistance. Karst water hydraulics is strongly governed by the interaction between a highly conductive low storage conduit network and a low‐conductive high‐storage rock matrix under variable boundary conditions. Only if this coupling of flow mechanisms is considered can an appropriate representation of other relevant processes be achieved, e.g., carbonate dissolution, transport of dissolved solids, and limited groundwater recharge. Here a parameter study performed with the numerical model Carbonate Aquifer Void Evolution (CAVE) is presented, which allows the simulation of the genesis of karst aquifers during geologic time periods. CAVE integrates several important features relevant for different scenarios of karst evolution: (1) the complex hydraulic interplay between flow in the karst conduits and in the small fissures of the rock matrix, (2) laminar as well as turbulent flow conditions, (3) time‐dependent and nonuniform recharge to both flow systems, (4) the widening of the conduits accounting for appropriate physicochemical relationships governing calcite dissolution kinetics. This is achieved by predefining an initial network of karst conduits (“protoconduits”) which are allowed to grow according to the amount of aggressive water available due to hydraulic boundary conditions. The increase in conduit transmissivity is associated with an increase in conduit diameters while the conductivity of the fissured system is assumed to be constant in time. The importance of various parameters controlling karst genesis is demonstrated in a parameter study covering the recharge distribution, the upgradient boundary conditions for the conduit system, and the hydraulic coupling between the conduit network and the rock matrix. In particular, it is shown that conduit diameters increase in downgradient or upgradient direction depending on the spatial distribution (local versus uniform) of the recharge component which directly enters the conduit system.",
    url = "https://doi.org/10.1029/2001wr001206",
    doi = "10.1029/2001wr001206",
    openalex = "W1631009898",
    references = "doi1010160016703776901769"
}

Calcite and dolomite solubilities in open weathering environments are proportional to p CO 2 and inversely proportional to temperature, and dolomite solubility is progressively greater than calcite below 25°C. The continent‐scale weathering budget reveals the significance of the Northern Hemisphere (NH) to globally integrated riverine fluxes of Ca 2+, Mg 2+, and HCO 3 −. The NH contributes 70% of the global HCO 3 − flux while only 54% of the riverine discharge. We present results of a comparative hydrogeochemical study of carbonate mineral equilibria and weathering fluxes in two NH carbonate‐rich river basins. Surface water geochemistry and discharge were determined for headwater streams in Michigan and Slovenia within the St. Lawrence and Danube river basins. Michigan watersheds are established atop carbonate‐bearing glacial drift deposits derived from erosion of Paleozoic strata with thick soil horizons (100–300 cm). Slovenia watersheds drain Mesozoic bedrock carbonates in alpine and dinaric karst environments with thin soil horizons (0–70 cm). Carbonate weathering intensity is a parameter that normalizes river runoff and HCO 3 − concentration to catchment area (meq HCO 3 − km −2 s −1), summing calcite and dolomite contributions, and is used to gauge the effects of climate, land use, and soil thickness on organic‐inorganic carbon processing rates. Importantly, Michigan riverine discharge is one‐tenth of Slovenian rivers, providing the opportunity to evaluate the kinetics of carbonate mineral equilibration. The study rivers are HCO 3 − − Ca 2+ − Mg 2+ waters, supersaturated for calcite at p CO 2 values in excess of the atmosphere. As discharge varies, HCO 3 − concentrations differ by less than 20% for any location, and Mg 2+ /Ca 2+ remains relatively fixed for Michigan (0.5) and Slovenia streams (0.4), requiring that dolomite dissolution exceed calcite on a mole basis. The ability of calcite and dolomite dissolution to keep pace with increased discharge indicates carbonate weathering is limited only by water flux and temperature‐dependent solubility in these watersheds. Carbonate weathering intensity in Michigan and Slovenia exceeds the world average by factors between 2 and 20, and dolomite weathering intensity, estimated from riverine Mg 2+ fluxes, exceeds the world average by factors between 2 and 15. Thus global fluxes of carbonate‐related weathering products appear heavily skewed toward carbonate‐bearing environments at higher latitudes with relatively low mean annual temperatures and high discharge.

@article{doi1010292006gc001337,
    author = "Szramek, Kathryn and McIntosh, Jennifer C. and Williams, E. L. and Kanduč, Tjaša and Ogrinc, Nives and Walter, Lynn M.",
    title = "Relative weathering intensity of calcite versus dolomite in carbonate‐bearing temperate zone watersheds: Carbonate geochemistry and fluxes from catchments within the St. Lawrence and Danube river basins",
    year = "2007",
    journal = "Geochemistry Geophysics Geosystems",
    abstract = "Calcite and dolomite solubilities in open weathering environments are proportional to p CO 2 and inversely proportional to temperature, and dolomite solubility is progressively greater than calcite below 25°C. The continent‐scale weathering budget reveals the significance of the Northern Hemisphere (NH) to globally integrated riverine fluxes of Ca 2+, Mg 2+, and HCO 3 −. The NH contributes 70\% of the global HCO 3 − flux while only 54\% of the riverine discharge. We present results of a comparative hydrogeochemical study of carbonate mineral equilibria and weathering fluxes in two NH carbonate‐rich river basins. Surface water geochemistry and discharge were determined for headwater streams in Michigan and Slovenia within the St. Lawrence and Danube river basins. Michigan watersheds are established atop carbonate‐bearing glacial drift deposits derived from erosion of Paleozoic strata with thick soil horizons (100–300 cm). Slovenia watersheds drain Mesozoic bedrock carbonates in alpine and dinaric karst environments with thin soil horizons (0–70 cm). Carbonate weathering intensity is a parameter that normalizes river runoff and HCO 3 − concentration to catchment area (meq HCO 3 − km −2 s −1), summing calcite and dolomite contributions, and is used to gauge the effects of climate, land use, and soil thickness on organic‐inorganic carbon processing rates. Importantly, Michigan riverine discharge is one‐tenth of Slovenian rivers, providing the opportunity to evaluate the kinetics of carbonate mineral equilibration. The study rivers are HCO 3 − − Ca 2+ − Mg 2+ waters, supersaturated for calcite at p CO 2 values in excess of the atmosphere. As discharge varies, HCO 3 − concentrations differ by less than 20\% for any location, and Mg 2+ /Ca 2+ remains relatively fixed for Michigan (0.5) and Slovenia streams (0.4), requiring that dolomite dissolution exceed calcite on a mole basis. The ability of calcite and dolomite dissolution to keep pace with increased discharge indicates carbonate weathering is limited only by water flux and temperature‐dependent solubility in these watersheds. Carbonate weathering intensity in Michigan and Slovenia exceeds the world average by factors between 2 and 20, and dolomite weathering intensity, estimated from riverine Mg 2+ fluxes, exceeds the world average by factors between 2 and 15. Thus global fluxes of carbonate‐related weathering products appear heavily skewed toward carbonate‐bearing environments at higher latitudes with relatively low mean annual temperatures and high discharge.",
    url = "https://doi.org/10.1029/2006gc001337",
    doi = "10.1029/2006gc001337",
    openalex = "W2126201443",
    references = "doi1010160022169484900453"
}

@article{doi101007s1004001006113,
    author = "Goldscheider, Nico and Mádl‐Szőnyi, Judit and Erőss, Anita and Schill, Eva",
    title = "Review: Thermal water resources in carbonate rock aquifers",
    year = "2010",
    journal = "Hydrogeology Journal",
    url = "https://doi.org/10.1007/s10040-010-0611-3",
    doi = "10.1007/s10040-010-0611-3",
    openalex = "W1656856957",
    references = "doi101007s100400050176, doi1010160016703776901769"
}

The present work provides hydrochemical and stable isotope data and their interpretations for 54 springs and 20 wells, monitored from 2002 to 2006, in the Southern Latium region of Central Italy to identify flow paths, recharge areas and hydrochemical processes governing the evolution of groundwater in this region. The hydrogeological conceptual model of the carbonate aquifers of southern Latium was based on environmental isotopic and hydrochemical investigation techniques to characterize and model these aquifer systems with the aim of achieving proper management and protection of these important resources. Most of the spring samples, issuing from Lepini, Ausoni and Aurunci Mts., are characterized as Ca-Mg-HCO3 water type, however, some samples show a composition of Na-Cl and mixed Ca-Na-HCO3-Cl waters. Groundwater samples from Pontina Plain are mostly characterized by Na-Cl and Ca-Cl type waters. Geochemical modeling and saturation index computation of the Lepini, Ausoni Aurunci springs and Pontina Plain wells shows an interaction with carbonate rocks. Most of the spring and well water samples were saturated with respect to calcite and dolomite, however all sampled waters were undersaturated with respect to gypsum and halite. The relationship between δ18O and δ2H, for spring and well water samples, shows shifts of both the slope and the deuterium excess when compared to the world meteoric (WMWL) and central Italy meteoric (CIMWL) water lines. The deviation of data points from the meteoric lines can be attributed to evaporation both during the falling of the rain and by run-off on the ground surface before infiltration. Most springs and wells have a deuterium excess above 10 ‰ suggesting the precipitation in the groundwater comes from the Mediterranean sector. On the basis of local isotopic gradients, in combination with topographic and geologic criteria, four recharge areas were identified in the Aurunci Mountains. In Pontina Plain, the elevations of the recharging areas suggest that the Lepini carbonate aquifers are feeding them.

@article{doi104236jwarp201249080,
    author = "Sappa, Giuseppe and Barbieri, Maurizio and Ergul, Sibel and Ferranti, Flavia",
    title = "Hydrogeological Conceptual Model of Groundwater from Carbonate Aquifers Using Environmental Isotopes (\<sup\>18\</sup\>O, \<sup\>2\</sup\>H) and Chemical Tracers: A Case Study in Southern Latium Region, Central Italy",
    year = "2012",
    journal = "Journal of Water Resource and Protection",
    abstract = "The present work provides hydrochemical and stable isotope data and their interpretations for 54 springs and 20 wells, monitored from 2002 to 2006, in the Southern Latium region of Central Italy to identify flow paths, recharge areas and hydrochemical processes governing the evolution of groundwater in this region. The hydrogeological conceptual model of the carbonate aquifers of southern Latium was based on environmental isotopic and hydrochemical investigation techniques to characterize and model these aquifer systems with the aim of achieving proper management and protection of these important resources. Most of the spring samples, issuing from Lepini, Ausoni and Aurunci Mts., are characterized as Ca-Mg-HCO3 water type, however, some samples show a composition of Na-Cl and mixed Ca-Na-HCO3-Cl waters. Groundwater samples from Pontina Plain are mostly characterized by Na-Cl and Ca-Cl type waters. Geochemical modeling and saturation index computation of the Lepini, Ausoni Aurunci springs and Pontina Plain wells shows an interaction with carbonate rocks. Most of the spring and well water samples were saturated with respect to calcite and dolomite, however all sampled waters were undersaturated with respect to gypsum and halite. The relationship between δ18O and δ2H, for spring and well water samples, shows shifts of both the slope and the deuterium excess when compared to the world meteoric (WMWL) and central Italy meteoric (CIMWL) water lines. The deviation of data points from the meteoric lines can be attributed to evaporation both during the falling of the rain and by run-off on the ground surface before infiltration. Most springs and wells have a deuterium excess above 10 ‰ suggesting the precipitation in the groundwater comes from the Mediterranean sector. On the basis of local isotopic gradients, in combination with topographic and geologic criteria, four recharge areas were identified in the Aurunci Mountains. In Pontina Plain, the elevations of the recharging areas suggest that the Lepini carbonate aquifers are feeding them.",
    url = "https://doi.org/10.4236/jwarp.2012.49080",
    doi = "10.4236/jwarp.2012.49080",
    openalex = "W1999919992",
    references = "doi1010160022169484900453"
}

@article{chuman2013does,
    author = "Chuman, Tomáš and Hruška, Jakub and Oulehle, Filip and Gürtlerová, Pavla and Majer, Vladimír",
    title = "Does stream water chemistry reflect watershedcharacteristics?",
    year = "2013",
    journal = "Environmental Monitoring and Assessment",
    url = "https://doi.org/10.1007/s10661-012-2976-3",
    doi = "10.1007/s10661-012-2976-3",
    number = "7",
    openalex = "W2003702101",
    pages = "5683-5701",
    volume = "185",
    references = "doi101016001670379290334f, doi101016b9780080959757005076, doi101017cbo9780511525575, doi101017cbo9780511615146, doi10102995gb02925, doi101038nature06316, doi101046j136524271997d01539x, doi101146annurevecolsys35120202110122, openalexw1587627133, openalexw1591787667"
}

Karst aquifers contribute substantially to freshwater supplies in many regions of the world, but are vulnerable to contamination and difficult to manage because of their unique hydrogeological characteristics. Many karst systems are hydraulically connected over wide areas and require transboundary exploration, protection and management. In order to obtain a better global overview of karst aquifers, to create a basis for sustainable international water-resources management, and to increase the awareness in the public and among decision makers, the World Karst Aquifer Mapping (WOKAM) project was established. The goal is to create a world map and database of karst aquifers, as a further development of earlier maps. This paper presents the basic concepts and the detailed mapping procedure, using France as an example to illustrate the step-by-step workflow, which includes generalization, differentiation of continuous and discontinuous carbonate and evaporite rock areas, and the identification of non-exposed karst aquifers. The map also shows selected caves and karst springs, which are collected in an associated global database. The draft karst aquifer map of Europe shows that 21.6% of the European land surface is characterized by the presence of (continuous or discontinuous) carbonate rocks; about 13.8% of the land surface is carbonate rock outcrop.

@article{doi101007s1004001615193,
    author = "Chen, Zhao and Auler, Augusto S. and Bakalowicz, Michel and Drew, David and Griger, Franziska and Hartmann, Jens and Jiang, Guanghui and Moosdorf, Nils and Richts, Andrea and Stevanović, Zoran and Veni, George and Goldscheider, Nico",
    title = "The World Karst Aquifer Mapping project: concept, mapping procedure and map of Europe",
    year = "2017",
    journal = "Hydrogeology Journal",
    abstract = "Karst aquifers contribute substantially to freshwater supplies in many regions of the world, but are vulnerable to contamination and difficult to manage because of their unique hydrogeological characteristics. Many karst systems are hydraulically connected over wide areas and require transboundary exploration, protection and management. In order to obtain a better global overview of karst aquifers, to create a basis for sustainable international water-resources management, and to increase the awareness in the public and among decision makers, the World Karst Aquifer Mapping (WOKAM) project was established. The goal is to create a world map and database of karst aquifers, as a further development of earlier maps. This paper presents the basic concepts and the detailed mapping procedure, using France as an example to illustrate the step-by-step workflow, which includes generalization, differentiation of continuous and discontinuous carbonate and evaporite rock areas, and the identification of non-exposed karst aquifers. The map also shows selected caves and karst springs, which are collected in an associated global database. The draft karst aquifer map of Europe shows that 21.6\% of the European land surface is characterized by the presence of (continuous or discontinuous) carbonate rocks; about 13.8\% of the land surface is carbonate rock outcrop.",
    url = "https://doi.org/10.1007/s10040-016-1519-3",
    doi = "10.1007/s10040-016-1519-3",
    openalex = "W2578335399",
    references = "doi1010022013rg000443, doi101002hyp7332, doi101016jmarpetgeo201011006"
}

Abstract Stream habitat restoration and supplemental stocking of hatchery‐reared fish have increasingly become key components of recovery plans for imperiled freshwater fish; however, determining when to discontinue stocking efforts, prioritizing restoration areas, and evaluating restoration success present a conservation challenge. In this study, we demonstrate that otolith microchemistry is an effective tool for establishing natal origin of the June Sucker Chasmistes liorus, an imperiled potamodromous fish. This approach allows us to determine whether a fish is of wild or hatchery origin in order to assess whether habitat restoration enhances recruitment and to further identify areas of critical habitat. Our specific objectives were to (1) quantify and characterize chemical variation among three main spawning tributaries; (2) understand the relationship between otolith microchemistry and tributary chemistry; and (3) develop and validate a classification model to identify stream origin using otolith microchemistry data. We quantified molar ratios of Sr:Ca, Ba:Ca, and Mg:Ca for water and otolith chemistry from three main tributaries to Utah Lake, Utah, during the summer of 2013. Water chemistry (log e transformed Sr:Ca, Ba:Ca, and Mg:Ca ratios) differed significantly across all three spawning tributaries. We determined that Ba:Ca and Sr:Ca ratios were the most important variables driving our classification models, and we observed a strong linear relationship between water and otolith values for Sr:Ca and Ba:Ca but not for Mg:Ca. Classification models derived from otolith element: Ca signatures accurately sorted individuals to their experimental tributary of origin (classification tree: 89% accuracy; random forest model: 91% accuracy) and determined wild versus hatchery origin with 100% accuracy. Overall, this study aids in evaluating the effectiveness of restoration, tracking progress toward recovery, and prioritizing future restoration plans for fishes of conservation concern. Our results have further application, such as identifying subpopulations that provide the greatest reproductive contribution to a metapopulation or finding the reproductive area and origin of invasive fishes. Received August 27, 2016; accepted February 28, 2017 Published online May 22, 2017

@article{doi1010800002848720171301994,
    author = "Strohm, Deanna D. and Budy, Phaedra and Crowl, Todd A.",
    title = "Matching Watershed and Otolith Chemistry to Establish Natal Origin of an Endangered Desert Lake Sucker",
    year = "2017",
    journal = "Transactions of the American Fisheries Society",
    abstract = "Abstract Stream habitat restoration and supplemental stocking of hatchery‐reared fish have increasingly become key components of recovery plans for imperiled freshwater fish; however, determining when to discontinue stocking efforts, prioritizing restoration areas, and evaluating restoration success present a conservation challenge. In this study, we demonstrate that otolith microchemistry is an effective tool for establishing natal origin of the June Sucker Chasmistes liorus, an imperiled potamodromous fish. This approach allows us to determine whether a fish is of wild or hatchery origin in order to assess whether habitat restoration enhances recruitment and to further identify areas of critical habitat. Our specific objectives were to (1) quantify and characterize chemical variation among three main spawning tributaries; (2) understand the relationship between otolith microchemistry and tributary chemistry; and (3) develop and validate a classification model to identify stream origin using otolith microchemistry data. We quantified molar ratios of Sr:Ca, Ba:Ca, and Mg:Ca for water and otolith chemistry from three main tributaries to Utah Lake, Utah, during the summer of 2013. Water chemistry (log e transformed Sr:Ca, Ba:Ca, and Mg:Ca ratios) differed significantly across all three spawning tributaries. We determined that Ba:Ca and Sr:Ca ratios were the most important variables driving our classification models, and we observed a strong linear relationship between water and otolith values for Sr:Ca and Ba:Ca but not for Mg:Ca. Classification models derived from otolith element: Ca signatures accurately sorted individuals to their experimental tributary of origin (classification tree: 89\% accuracy; random forest model: 91\% accuracy) and determined wild versus hatchery origin with 100\% accuracy. Overall, this study aids in evaluating the effectiveness of restoration, tracking progress toward recovery, and prioritizing future restoration plans for fishes of conservation concern. Our results have further application, such as identifying subpopulations that provide the greatest reproductive contribution to a metapopulation or finding the reproductive area and origin of invasive fishes. Received August 27, 2016; accepted February 28, 2017 Published online May 22, 2017",
    url = "https://doi.org/10.1080/00028487.2017.1301994",
    doi = "10.1080/00028487.2017.1301994",
    openalex = "W771718005",
    references = "chuman2013does"
}

Abstract Mounting evidence suggests ecosystem changes that alter subsurface water fluxes and carbon dioxide concentrations in carbonate terrains may drive measurable changes in chemical weathering rates, stream water chemistry, and flow path evolution on human timescales. We test this idea by exploring if the encroachment of woody vegetation into grasslands in a carbonate terrain landscape at the Konza Prairie (KS, USA) has resulted in differences in landscape-stream connectivity and, thus, the behavior of stream water solutes. Woody encroachment (up to 60% cover) at Konza has been observed on watersheds, particularly those that experience a fire return interval of four years or greater. We focus on three headwater catchments (two grassland and one woody-encroached) and a downstream confluence, and analyze stream water discharge and chemistry (major anions, cations, and dissolved nutrients) measured from 2015 to 2016. We observe that the woody-encroached watershed exhibits a greater area-normalized solute flux and greater degree of chemodynamic behavior for most geogenic species compared to the less encroached grassland watersheds. The downstream confluence exhibits the most chemostatic behavior for these same solutes compared to the low order watersheds. We interpret the chemodynamic behavior of the woody-encroached watersheds to arise from a greater diversity of flow paths and solute sources that contribute to this stream. End member mixing analysis (EMMA) supports this hypothesis but also indicates a possible “missing” end member which we interpret to be solutes likely derived from clay weathering along limestone-mudstone boundaries. We invoke differences in rooting systems between grass and woody species to explain the differences in flow paths and solute generation between these headwater sites given that they sit adjacent to each other, dissect the same nearly horizontal (dip 0.1–0.21°NW) lithologic units, and experience the same climate. If these processes hold true at other sites, then the globally observed encroachment of woody vegetation into grasslands may deepen flow paths and enhance chemical weathering fluxes from ecosystems, and over long-time periods alter the trajectory of soil development and landscape evolution.

@article{doi101016jchemgeo201812002,
    author = "Sullivan, P. and Stops, Marvin Wes and Macpherson, G. and Li, Li and Hirmas, D. and Dodds, W.",
    title = "How landscape heterogeneity governs stream water concentration-discharge behavior in carbonate terrains (Konza Prairie, USA)",
    year = "2019",
    journal = "Chemical Geology",
    abstract = "Abstract Mounting evidence suggests ecosystem changes that alter subsurface water fluxes and carbon dioxide concentrations in carbonate terrains may drive measurable changes in chemical weathering rates, stream water chemistry, and flow path evolution on human timescales. We test this idea by exploring if the encroachment of woody vegetation into grasslands in a carbonate terrain landscape at the Konza Prairie (KS, USA) has resulted in differences in landscape-stream connectivity and, thus, the behavior of stream water solutes. Woody encroachment (up to 60\% cover) at Konza has been observed on watersheds, particularly those that experience a fire return interval of four years or greater. We focus on three headwater catchments (two grassland and one woody-encroached) and a downstream confluence, and analyze stream water discharge and chemistry (major anions, cations, and dissolved nutrients) measured from 2015 to 2016. We observe that the woody-encroached watershed exhibits a greater area-normalized solute flux and greater degree of chemodynamic behavior for most geogenic species compared to the less encroached grassland watersheds. The downstream confluence exhibits the most chemostatic behavior for these same solutes compared to the low order watersheds. We interpret the chemodynamic behavior of the woody-encroached watersheds to arise from a greater diversity of flow paths and solute sources that contribute to this stream. End member mixing analysis (EMMA) supports this hypothesis but also indicates a possible “missing” end member which we interpret to be solutes likely derived from clay weathering along limestone-mudstone boundaries. We invoke differences in rooting systems between grass and woody species to explain the differences in flow paths and solute generation between these headwater sites given that they sit adjacent to each other, dissect the same nearly horizontal (dip 0.1–0.21°NW) lithologic units, and experience the same climate. If these processes hold true at other sites, then the globally observed encroachment of woody vegetation into grasslands may deepen flow paths and enhance chemical weathering fluxes from ecosystems, and over long-time periods alter the trajectory of soil development and landscape evolution.",
    url = "https://www.semanticscholar.org/paper/308fbe8009111b98d0ef48c02deab451c475e8f6",
    doi = "10.1016/J.CHEMGEO.2018.12.002",
    is_oa = "true",
    pages = "118989",
    semanticscholar_citation_count = "55",
    semanticscholar_id = "308fbe8009111b98d0ef48c02deab451c475e8f6",
    volume = "527"
}

The University of Kentucky (U KY) has owned Robinson Forest (37.460723° N, 83.158598° W) since 1923, conducting experiments crucial to understanding the environmental effects of land management in the region. Part of the management of Robinson Forest has been collection of environmental data, including precipitation quantity, bulk‐deposition chemistry, streamflow, stream‐water chemistry, and air and stream temperature. Over the years, these data have been collected and archived using various technologies and have been mostly inaccessible for research use – unedited and uncompiled, scattered across several spreadsheets and paper records. Through a partnership between the U.S. Geological Survey (USGS) and U KY, daily precipitation data for six stations and stream data from four watersheds in Robinson Forest have been compiled for 1971–2018, checked for transcription errors, and annotated for changes in methodologies. These data are available as a USGS data release at https://doi.org/10.5066/P9FPLG1O. Improved accessibility of this data set provides an important research resource for understanding water quality in minimally effected forests in the region. Preliminary results indicate that these data present a valuable opportunity to evaluate linkages among atmospheric deposition and stream chemistry, the effects of environmental policy, such as the Clean Air Act, and effects from nearby land disturbance in the form of surface mining. Furthermore, these data fill a geographic and physiographic gap in what is available to examine deposition and streamflow patterns over the last 45 years, supplementing those long‐term records of research sites in northern (e.g., Hubbard Brook Experimental Forest), central (e.g., Fernow Experimental Forest) and southern Appalachia (e.g., Coweeta Hydrologic Laboratory). As an oasis in the midst of significant surface mining activity, Robinson Forest presents a unique opportunity to understand environmental conditions characteristic of minimally disturbed forests similar to pre‐mining conditions in the Central Appalachian region.

@article{doi101002hyp14133,
    author = "Sena, Kenton L. and Williamson, T. and Barton, C.",
    title = "The Robinson Forest environmental monitoring network: Long‐term evaluation of streamflow and precipitation quantity and stream‐water and bulk deposition chemistry in eastern Kentucky watersheds",
    year = "2021",
    journal = "Hydrological Processes",
    abstract = "The University of Kentucky (U KY) has owned Robinson Forest (37.460723° N, 83.158598° W) since 1923, conducting experiments crucial to understanding the environmental effects of land management in the region. Part of the management of Robinson Forest has been collection of environmental data, including precipitation quantity, bulk‐deposition chemistry, streamflow, stream‐water chemistry, and air and stream temperature. Over the years, these data have been collected and archived using various technologies and have been mostly inaccessible for research use – unedited and uncompiled, scattered across several spreadsheets and paper records. Through a partnership between the U.S. Geological Survey (USGS) and U KY, daily precipitation data for six stations and stream data from four watersheds in Robinson Forest have been compiled for 1971–2018, checked for transcription errors, and annotated for changes in methodologies. These data are available as a USGS data release at https://doi.org/10.5066/P9FPLG1O. Improved accessibility of this data set provides an important research resource for understanding water quality in minimally effected forests in the region. Preliminary results indicate that these data present a valuable opportunity to evaluate linkages among atmospheric deposition and stream chemistry, the effects of environmental policy, such as the Clean Air Act, and effects from nearby land disturbance in the form of surface mining. Furthermore, these data fill a geographic and physiographic gap in what is available to examine deposition and streamflow patterns over the last 45 years, supplementing those long‐term records of research sites in northern (e.g., Hubbard Brook Experimental Forest), central (e.g., Fernow Experimental Forest) and southern Appalachia (e.g., Coweeta Hydrologic Laboratory). As an oasis in the midst of significant surface mining activity, Robinson Forest presents a unique opportunity to understand environmental conditions characteristic of minimally disturbed forests similar to pre‐mining conditions in the Central Appalachian region.",
    url = "https://www.semanticscholar.org/paper/906ccf32bdc76727bfc72b2aef58eb7379e69853",
    doi = "10.1002/hyp.14133",
    is_oa = "true",
    number = "4",
    semanticscholar_citation_count = "7",
    semanticscholar_id = "906ccf32bdc76727bfc72b2aef58eb7379e69853",
    volume = "35"
}

Abstract Radiogenic strontium isotopic ratios (87Sr/86Sr) and solute concentrations in groundwater samples from the coastal area of the eastern Yucatan Peninsula, Quintana Roo, Mexico were measured to assess connectivity and water-rock interactions within different groundwater systems in the region. The average 87Sr/86Sr ratios vary from south to north with values in Xcalak around 0.70889, Sian Ka'an around 0.70847 and at Cancun and Puerto Morelos around 0.70880. The values show 3 clusters suggesting 3 distinct groundwater systems, Cancun-Puerto Morelos in the north, Tulum-Sian Ka'an in the center and Xcalak in the South. Water-rock interactions, while unique within each aquifer system, encompass processes observed throughout the Yucatan karst system including dissolution of evaporites, precipitation of carbonate, sulfate reduction and mixing with seawater. This study highlights the use of groundwater chemistry of understanding groundwater connectivity and the importance of potential distal anthropogenic impacts on groundwater quality and related effect on coastal population and ecosystems.

@article{doi101016jcsr2020104293,
    author = "Hernández-Terrones, L. and Street, J. and Null, K. and Paytan, A.",
    title = "Groundwater chemistry and Sr isotope ratios shed light on connectivity and water-rock interactions in the coastal aquifer of the Caribbean coast, Mexico",
    year = "2021",
    journal = "Continental Shelf Research",
    abstract = "Abstract Radiogenic strontium isotopic ratios (87Sr/86Sr) and solute concentrations in groundwater samples from the coastal area of the eastern Yucatan Peninsula, Quintana Roo, Mexico were measured to assess connectivity and water-rock interactions within different groundwater systems in the region. The average 87Sr/86Sr ratios vary from south to north with values in Xcalak around 0.70889, Sian Ka'an around 0.70847 and at Cancun and Puerto Morelos around 0.70880. The values show 3 clusters suggesting 3 distinct groundwater systems, Cancun-Puerto Morelos in the north, Tulum-Sian Ka'an in the center and Xcalak in the South. Water-rock interactions, while unique within each aquifer system, encompass processes observed throughout the Yucatan karst system including dissolution of evaporites, precipitation of carbonate, sulfate reduction and mixing with seawater. This study highlights the use of groundwater chemistry of understanding groundwater connectivity and the importance of potential distal anthropogenic impacts on groundwater quality and related effect on coastal population and ecosystems.",
    url = "https://www.semanticscholar.org/paper/d6abab6e82bb2a1bbaf3170d7dfadc7a1518eb17",
    doi = "10.1016/j.csr.2020.104293",
    is_oa = "true",
    pages = "104293",
    semanticscholar_citation_count = "10",
    semanticscholar_id = "d6abab6e82bb2a1bbaf3170d7dfadc7a1518eb17",
    volume = "212"
}

@inproceedings{andhopt2023the,
    author = "Hopt, Brett and Perkins, Robert",
    title = "THE IMPACT OF BLACK SHALE WEATHERING ON STREAM AND STREAM SEDIMENT CHEMISTRY IN EASTERN KENTUCKY",
    year = "2023",
    booktitle = "Geological Society of America Abstracts with Programs",
    url = "https://doi.org/10.1130/abs/2023am-395536",
    doi = "10.1130/abs/2023am-395536",
    openalex = "W4389357763"
}

@incollection{das2023carbonate,
    author = "Das, Sourav",
    title = "Carbonate Chemistry of Water",
    year = "2023",
    booktitle = "An Introduction to Water Quality Science",
    url = "https://doi.org/10.1007/978-3-031-42137-2\_5",
    doi = "10.1007/978-3-031-42137-2\_5",
    openalex = "W4387016364",
    pages = "79-101",
    references = "doi101002qj49709841707, doi10102993gb02263, doi10102993gb02524, doi10102997gb00077, doi10103835037500, doi101038383495a0, doi10103841474, doi101126science2815374200, doi105194essd1448112022, openalexw1845417433"
}

Water pollution with potentially toxic elements (PTEs) becomes a major threat to the validity of that water for drinking and agriculture and hence human life. The current study aims to evaluate the carbonate aquifer groundwater PTE content, sources, and impact on water quality. To achieve this goal, drilling cutoff of two wells and 30 groundwater samples were collected and chemically analyzed. The groundwater has TDS values ranged from 271.2 to 971.8 mg/l. Freshwater recharge process led to the continuous freshening of the aquifer and enhanced the forward ion exchange reactions. Carbonate and evaporate mineral dissolution/precipitation processes are the main controller of groundwater chemistry. Cd and As represented the most hazardous elements in these rocks followed by Pb. The presence of high concentrations of PTEs (As, Cd, Cr, and Pb) in water-bearing carbonate rocks has led to detritus of water quality and its unsuitability for drinking owing to the occurrence of these harmful elements in water. Even though the high concentrations of PTEs in the studied water, these elements occurred in low mobility and toxicity species: Fe(OH)3, Mn2+, (HAsO4)−2, Cd2+, Cr2O3, Cu2O, CuO, and PbCO3. This reflects the importance of studying element species rather than total concentration. Even though the unsuitability of this water for drinking owing to high concentrations of some PTEs, all of the samples were found to be suitable for irrigation.

@article{doi101007s1127002306773z,
    author = "Abdel-Aziz, Abdel-Aziz A. and Salman, S. and Ismail, Esam and Mostafa, Alaa and Mohamed, Ramadan S. A.",
    title = "Potentially Toxic Element (PTE) Sources in the Middle Eocene Carbonate Aquifer, East El Minia, Egypt",
    year = "2023",
    journal = "Water, Air, \& Soil Pollution",
    abstract = "Water pollution with potentially toxic elements (PTEs) becomes a major threat to the validity of that water for drinking and agriculture and hence human life. The current study aims to evaluate the carbonate aquifer groundwater PTE content, sources, and impact on water quality. To achieve this goal, drilling cutoff of two wells and 30 groundwater samples were collected and chemically analyzed. The groundwater has TDS values ranged from 271.2 to 971.8 mg/l. Freshwater recharge process led to the continuous freshening of the aquifer and enhanced the forward ion exchange reactions. Carbonate and evaporate mineral dissolution/precipitation processes are the main controller of groundwater chemistry. Cd and As represented the most hazardous elements in these rocks followed by Pb. The presence of high concentrations of PTEs (As, Cd, Cr, and Pb) in water-bearing carbonate rocks has led to detritus of water quality and its unsuitability for drinking owing to the occurrence of these harmful elements in water. Even though the high concentrations of PTEs in the studied water, these elements occurred in low mobility and toxicity species: Fe(OH)3, Mn2+, (HAsO4)−2, Cd2+, Cr2O3, Cu2O, CuO, and PbCO3. This reflects the importance of studying element species rather than total concentration. Even though the unsuitability of this water for drinking owing to high concentrations of some PTEs, all of the samples were found to be suitable for irrigation.",
    url = "https://link.springer.com/content/pdf/10.1007/s11270-023-06773-z.pdf",
    doi = "10.1007/s11270-023-06773-z",
    is_oa = "true",
    number = "1",
    semanticscholar_citation_count = "1",
    semanticscholar_id = "c0290dd285b72f71a267ce1803a788f1fe224181",
    volume = "235"
}

Carbonic acid and sulfuric acid speleogenesis describe a dichotomy between epigenetic and hypogenetic caves and carbon and sulfur cycling in karst, but do not acknowledge the global spectrum of cave formation. This paper, part one of a two-part investigation, tests and revises speleogenetic models from a classic karst landscape using dissolved ion concentrations δ13CDIC, and δ34S in water samples collected at four sites across the Bluespring and Lost River karst basins in the Mitchell Plateau, Indiana, USA. Analyses revealed elevated sulfur in both karst basins but differently sourced; H2S (δ34S = −14.2‰) evolved from petroleum seeps in Bluespring Caverns accounted for up to 61% of sulfur in the cave stream, while evaporite beds (δ34S = [+14.50‰, +17.91‰]) of the St. Louis Limestone contributed up to 100% of sulfur at Orangeville Rise, a terminal spring of the Lost River karst basin. These results have implications for carbon–sulfur cycle linkages, particularly the potential acceleration of carbon flux from sulfuric acid dissolution in otherwise epigenetic settings. We suggest a new paradigm for speleogenesis in the North American midcontinent—speleogenesis in the Mitchell Plateau and similar settings is not epigenetic or hypogenetic, but instead polygenetic with competing chemical processes varying across space and time.

@article{doi103390w15193410,
    author = "Burgess, S. and Florea, L. and Branam, Tracy D.",
    title = "Divergent Geochemical Pathways of Carbonate Aquifer Evolution in a Classic Karst Terrain: (1) Polygenetic Cave Development Identified Using Longitudinal Groundwater Geochemistry",
    year = "2023",
    journal = "Water",
    abstract = "Carbonic acid and sulfuric acid speleogenesis describe a dichotomy between epigenetic and hypogenetic caves and carbon and sulfur cycling in karst, but do not acknowledge the global spectrum of cave formation. This paper, part one of a two-part investigation, tests and revises speleogenetic models from a classic karst landscape using dissolved ion concentrations δ13CDIC, and δ34S in water samples collected at four sites across the Bluespring and Lost River karst basins in the Mitchell Plateau, Indiana, USA. Analyses revealed elevated sulfur in both karst basins but differently sourced; H2S (δ34S = −14.2‰) evolved from petroleum seeps in Bluespring Caverns accounted for up to 61\% of sulfur in the cave stream, while evaporite beds (δ34S = [+14.50‰, +17.91‰]) of the St. Louis Limestone contributed up to 100\% of sulfur at Orangeville Rise, a terminal spring of the Lost River karst basin. These results have implications for carbon–sulfur cycle linkages, particularly the potential acceleration of carbon flux from sulfuric acid dissolution in otherwise epigenetic settings. We suggest a new paradigm for speleogenesis in the North American midcontinent—speleogenesis in the Mitchell Plateau and similar settings is not epigenetic or hypogenetic, but instead polygenetic with competing chemical processes varying across space and time.",
    url = "https://www.mdpi.com/2073-4441/15/19/3410/pdf?version=1695886978",
    doi = "10.3390/w15193410",
    is_oa = "true",
    number = "19",
    pages = "3410",
    semanticscholar_citation_count = "4",
    semanticscholar_id = "4b302de19d60fc08b1321fe5c308e703b2b01136",
    volume = "15"
}

Springs provide ideal monitoring points for groundwater chemistry, which are important for managing groundwater resources. The chemistry of these spring waters aggregate geochemical reactions along the flow path. In this paper, part two of a two-part investigation, 104 perennial springs in the classic karst landscape of the Mitchell Plateau, Indiana, USA were sampled at base flow. Many of these springs are historically important for domestic, agricultural, commercial, and recreational use. Multifactor analysis of field measurements, principal ions, and stable isotopes revealed five primary clusters of springs emerging from the Mitchell Aquifer. Two clusters represented earth-alkaline-type karst groundwater that were discriminated by temperature and inorganic carbon concentration. Two other clusters comprised mineralized alkaline-earth-type groundwater with excess alkalis and elevated sulfate. The fifth cluster appeared to be groundwater that included meteoric and mineralized sources. Using the longitudinal data over two years from part one of this investigation, two mixing lines were used to describe the data set. The mixing lines pointed to sources of sulfur in mineralized springs from deep brines and from evaporite dissolution. Collectively, these regional data allow for a better delineation of water types and differentiation between the Upper and Lower Mitchell Aquifer.

@article{doi103390w15193436,
    author = "Burgess, S. and Branam, Tracy D. and Florea, L.",
    title = "Divergent Geochemical Pathways of Carbonate Aquifer Evolution in a Classic Karst Terrain: (2) Groundwater Source Delineation Using Regional Water Chemistry Data",
    year = "2023",
    journal = "Water",
    abstract = "Springs provide ideal monitoring points for groundwater chemistry, which are important for managing groundwater resources. The chemistry of these spring waters aggregate geochemical reactions along the flow path. In this paper, part two of a two-part investigation, 104 perennial springs in the classic karst landscape of the Mitchell Plateau, Indiana, USA were sampled at base flow. Many of these springs are historically important for domestic, agricultural, commercial, and recreational use. Multifactor analysis of field measurements, principal ions, and stable isotopes revealed five primary clusters of springs emerging from the Mitchell Aquifer. Two clusters represented earth-alkaline-type karst groundwater that were discriminated by temperature and inorganic carbon concentration. Two other clusters comprised mineralized alkaline-earth-type groundwater with excess alkalis and elevated sulfate. The fifth cluster appeared to be groundwater that included meteoric and mineralized sources. Using the longitudinal data over two years from part one of this investigation, two mixing lines were used to describe the data set. The mixing lines pointed to sources of sulfur in mineralized springs from deep brines and from evaporite dissolution. Collectively, these regional data allow for a better delineation of water types and differentiation between the Upper and Lower Mitchell Aquifer.",
    url = "https://www.mdpi.com/2073-4441/15/19/3436/pdf?version=1696072712",
    doi = "10.3390/w15193436",
    is_oa = "true",
    number = "19",
    pages = "3436",
    semanticscholar_citation_count = "3",
    semanticscholar_id = "0b1747936a468d405dc088167dbd49d1fe3ba097",
    volume = "15"
}

This study addresses the pressing issue of nonpoint source water pollution in Kentucky, particularly associated with large-scale agriculture. Centered on the outer bluegrass region of Central Kentucky, the research examines the water quality of headwater streams during the agricultural season. The approach involves geospatial land cover classification using aerial imagery. Water quality data were collected during the agricultural growing season from May to October 2018. Land cover classification utilized ERDAS Imagine 2016 and ESRI ArcGIS 10.6 GIS software, while conventional water quality parameters were measured with a YSI ProDSS® multiparameter water probe and a Marsh-McBirney Flo-Mate 2000 flow meter. Statistical analyses show significant differences in stream water chemistry, suggesting the impact of agricultural nonpoint source pollution. Forested streams exhibited more varied conditions, indicating a potentially better environment. As agricultural land percentage increased, water chemistry variation suggested a measurable threshold for changes. Significant differences in water quality between agricultural and forested streams highlight the potential benefits of expanding riparian zones beyond regulations. Enlarging these zones is proposed as a strategy to mitigate nonpoint source pollution in Kentucky’s waterways.

@article{doi103390app14072679,
    author = "Jones, Jarod and Gyawali, B. and Acharya, Shikha and Cristan, Richard and Gebremedhin, M.",
    title = "Assessing the Influence of Agricultural Nonpoint Source Pollution on Water Quality in Central Kentucky’s Headwater Streams",
    year = "2024",
    journal = "Applied Sciences",
    abstract = "This study addresses the pressing issue of nonpoint source water pollution in Kentucky, particularly associated with large-scale agriculture. Centered on the outer bluegrass region of Central Kentucky, the research examines the water quality of headwater streams during the agricultural season. The approach involves geospatial land cover classification using aerial imagery. Water quality data were collected during the agricultural growing season from May to October 2018. Land cover classification utilized ERDAS Imagine 2016 and ESRI ArcGIS 10.6 GIS software, while conventional water quality parameters were measured with a YSI ProDSS® multiparameter water probe and a Marsh-McBirney Flo-Mate 2000 flow meter. Statistical analyses show significant differences in stream water chemistry, suggesting the impact of agricultural nonpoint source pollution. Forested streams exhibited more varied conditions, indicating a potentially better environment. As agricultural land percentage increased, water chemistry variation suggested a measurable threshold for changes. Significant differences in water quality between agricultural and forested streams highlight the potential benefits of expanding riparian zones beyond regulations. Enlarging these zones is proposed as a strategy to mitigate nonpoint source pollution in Kentucky’s waterways.",
    url = "https://doi.org/10.3390/app14072679",
    doi = "10.3390/app14072679",
    is_oa = "true",
    number = "7",
    pages = "2679",
    semanticscholar_citation_count = "5",
    semanticscholar_id = "a838f6f71a234350d077ee5efb915416cceceb9e",
    volume = "14"
}

Monitoring changes in groundwater quality over time helps identify time-dependent factors influencing water safety and supports the development of effective management strategies. This study investigates the spatiotemporal evolution of groundwater chemistry in the Debrecen area, Hungary, from 2019 to 2024, using indexing, machine learning, and multivariate statistical techniques. These techniques include self-organizing maps (SOM), hierarchical cluster analysis (HCA), principal component analysis (PCA), and groundwater quality indexing (GWQI). The hydrochemical analysis revealed that Ca-Mg-HCO₃ is the dominant water type, with a temporal shift toward Na-HCO₃, reflecting increased salinity driven by ongoing rock-water interactions. SOM analysis showed a transition from heterogeneous to more uniform groundwater chemistry over time, suggesting greater stability in the aquifer system. Elevated salinity zones shifted spatially due to changes in groundwater recharge and flow patterns, while hardness intensified and expanded, indicating continued carbonate dissolution. HCA highlighted temporal shifts in groundwater composition, with six clusters identified in 2019 and five clusters in 2024, reflecting a gradual homogenization of water quality. PCA further confirmed this trend, linking it to underlying hydrochemical processes, such as water–rock interactions, with limited contributions from anthropogenic influences. The GWQI analysis indicated a general improvement in groundwater quality over time, with most regions meeting drinking water standards. However, specific areas exhibited signs of localized contamination, requiring targeted management. These findings underscore the importance of continuous groundwater quality monitoring to detect emerging trends and guide resource management. The study highlights the need for sustainable practices to safeguard water resources and ensure long-term water security in the Debrecen area.

@article{doi101007s1135602536175z,
    author = "Mohammed, Musaab A. A. and Szabó, N. and Mikita, V. and Szűcs, P.",
    title = "Tracking the spatiotemporal evolution of groundwater chemistry in the Quaternary aquifer system of Debrecen area, Hungary: integration of classical and unsupervised learning methods",
    year = "2025",
    journal = "Environmental Science and Pollution Research International",
    abstract = "Monitoring changes in groundwater quality over time helps identify time-dependent factors influencing water safety and supports the development of effective management strategies. This study investigates the spatiotemporal evolution of groundwater chemistry in the Debrecen area, Hungary, from 2019 to 2024, using indexing, machine learning, and multivariate statistical techniques. These techniques include self-organizing maps (SOM), hierarchical cluster analysis (HCA), principal component analysis (PCA), and groundwater quality indexing (GWQI). The hydrochemical analysis revealed that Ca-Mg-HCO₃ is the dominant water type, with a temporal shift toward Na-HCO₃, reflecting increased salinity driven by ongoing rock-water interactions. SOM analysis showed a transition from heterogeneous to more uniform groundwater chemistry over time, suggesting greater stability in the aquifer system. Elevated salinity zones shifted spatially due to changes in groundwater recharge and flow patterns, while hardness intensified and expanded, indicating continued carbonate dissolution. HCA highlighted temporal shifts in groundwater composition, with six clusters identified in 2019 and five clusters in 2024, reflecting a gradual homogenization of water quality. PCA further confirmed this trend, linking it to underlying hydrochemical processes, such as water–rock interactions, with limited contributions from anthropogenic influences. The GWQI analysis indicated a general improvement in groundwater quality over time, with most regions meeting drinking water standards. However, specific areas exhibited signs of localized contamination, requiring targeted management. These findings underscore the importance of continuous groundwater quality monitoring to detect emerging trends and guide resource management. The study highlights the need for sustainable practices to safeguard water resources and ensure long-term water security in the Debrecen area.",
    url = "https://www.semanticscholar.org/paper/a6e370c9ac1173fde32b69c23d8b6e7e695095bc",
    doi = "10.1007/s11356-025-36175-z",
    is_oa = "true",
    number = "11",
    pages = "6884-6903",
    semanticscholar_citation_count = "14",
    semanticscholar_id = "a6e370c9ac1173fde32b69c23d8b6e7e695095bc",
    volume = "32"
}