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Papers by Carol Wicks

Water

Most studies of carbonate bedrock weathering have focused on the dissolved inorganic carbon (DIC)... more Most studies of carbonate bedrock weathering have focused on the dissolved inorganic carbon (DIC) flux while dismissing particulate inorganic carbon (PIC) as insignificant. However, under certain flow conditions PIC flux may be an important term in carbonate weathering. In this study, the total inorganic carbon (TIC) flux was calculated in a fluviokarst basin. Water samples and in situ data loggers were used to determine suspended sediment concentration and water chemistry. The mass of PIC within suspended sediments was quantified by cation/anion analysis of dual filtered/unfiltered samples. The flux of bed load material was calculated via stream power calculations. The analysis of recorded storm events indicated that PIC flux is moderate but can be significant during peak storm discharges. A small storm with a 0.87-month return period produced a PIC flux of 14 g s−1 and a DIC flux of 150 g s−1 at 1.4 m3 s−1 discharge. The largest storm had a return period of 7.7 months, a peak disc...

Journal of Cave and Karst Studies, 1998

In this study, we explore the differences between the hydrogeochemical processes observed in a se... more In this study, we explore the differences between the hydrogeochemical processes observed in a setting that is open to input from the land surface and in a setting that is closed with respect to input from the land surface. The closed setting was a water-filled passage in a cave. Samples of groundwater and of a solid that appeared to be suspended in the relatively fresh region of saline-freshwater mixing zone were collected. The solid was determined to be aragonite. Based on the analyses of the composition and saturation state of the groundwater, the mixing of fresh and saline water and precipitation of aragonite are the controlling geochemical processes in this mixing zone. We found no evidence of sulfate reduction. Thus, this mixing zone is similar to that observed in Caleta Xel Ha, Quintana Roo, also a system that is closed with respect to input from the land surface. The open setting was an unconfined aquifer underlying the coastal plain along which four hand-dug wells are located. Two wells are at the downgradient ends of inferred flowpaths and one is along a flowpath. The composition of the groundwater in the downgradient wells is sulfide-rich and brackish. In contrast, at the well located along a flow line, the groundwater is oxygenated and brackish. All groundwater is oversaturated with respect to calcite, aragonite, and dolomite. The composition is attributed to mixing of fresh and saline groundwater, CO2 outgassing, and sulfate reduction. This mixing zone is geochemically similar to that observed in blue holes and cenotes.

Journal of College Science Teaching, 2014

Developments in environmental biology of fishes, 2001

Two troglobitic fishes of conservation concern that inhabit Missouri are the Ozark and southern c... more Two troglobitic fishes of conservation concern that inhabit Missouri are the Ozark and southern cavefishes, Amblyopsis rosae and Typhlichthys subterraneus, respectively. These species inhabit the groundwater of karstified bedrock in the Springfield and Salem plateau regions of the state, respectively. These two areas differ substantiallygeographically, geologically, and hydrologically. This paper explores how these differences interact in shaping (1) the habitat in which these two species dwell, (2) the resulting ecological constraints that the fishes face, (3) how their ecologies and populations reflect these constraints, and (4) how conservation and management efforts may need to be tailored to best compliment the unique challenges that each species presents.

International Journal of Speleology, 2006

This investigation quantifies how temperatures fluctuate in relation to discharge, seasonal, and ... more This investigation quantifies how temperatures fluctuate in relation to discharge, seasonal, and diurnal temperature variations. Furthermore, the linkages between meteorological processes and temperature variation in the hyporheic zone are delineated. Examination of a high-resolution, three dimensional record of temperature variation in a karst stream substrate provides insight into thermal disturbances in the hyporheic zone. Temperatures in the upper portion of the hyporheic zone are strongly linked to air temperatures via the surface water. The variation is considerably less as depth increases. The annual temperature variation in the lower portion of the shallow hyporheic zone is reduced by one-third, relative to the variation observed in the surface water and upper substrate. During storm events, the upper portion (0-5 cm) of the shallow hyporheic zone is subject to a thermal regime very similar to surface stream water. However, below these depths the sharpest temperature fluctuations are effectively muted within the stream substrate. More frequent diurnal variations, particularly those associated with baseflow conditions, are also dampened within the substrate.

Many of the aquatic animals that live in cave streams are threatened, endangered, or endemic. Man... more Many of the aquatic animals that live in cave streams are threatened, endangered, or endemic. Management plans needed to conserve the aquatic ecosystems within which these animals live must be based on an understanding of the food webs, life histories, and habitat suitability. However, for many of these ecosystems, there is very little information about the food webs, life histories, or habitat suitability. If information is available, that information is frequently incomplete. One aspect of habitat suitability is the stability of the streambed sediment. Sediment that can be scoured over a wide range of hydrologic conditions is not suitable habitat as scour events disrupt the streambed sediment resulting in dispersal or possibly death of the animals; whereas, sediment that cannot be scoured would be suitable habitat. Assessing sediment stability requires hydrologic and sedimentologic data and assessing habitat suitability requires population consensus data. Rarely are the three disp...

Eos, Transactions American Geophysical Union, 2007

Satellite study of natural gas flaring Global flaring of natural gas remained largely stable from... more Satellite study of natural gas flaring Global flaring of natural gas remained largely stable from 1995 through 2006, according to the first globally consistent survey of gas flar ing, conducted using low-light imaging data from the U.S. Air Force Defense Meteorologi cal Satellite Program. Flaring is a widespread method of disposing of natural gas when oil production and processing occurs in remote areas or in areas that lack infrastructure to make use of the gas. The survey results, announced on 30 August, found the amount of annual flaring is in the range of 150 to 170 billion cubic meters (bcm). The survey, commissioned by

Karst watersheds with significant losing streams represent a particularly vulnerable setting for ... more Karst watersheds with significant losing streams represent a particularly vulnerable setting for ground water contamination because of the direct connection to surface water. Improvement of water quality in this type of karst setting faces many of the same management challenges as typical surface watersheds with regards to implementation of best management practices and responsible development in urbanizing areas. Because of the existing agricultural land-use and future threat of heavy urbanization, two losing stream karst basins were chosen for intensive monitoring in Boone County, Missouri: Hunters Cave and Devils Icebox Cave. Land use within both watersheds is similar with nearly equal percentages of row-crops, grasslands, and forest. Year-round monitoring was initiated in April 1999 with the objective of characterizing the water quality status of the main cave streams relative to herbicide, nutrient, and coliform bacterial contamina- tion. Water sampling for contaminants entails...

Water Resources Research, 2009

The responses of karstic aquifers to storms are often used to obtain information about aquifer ge... more The responses of karstic aquifers to storms are often used to obtain information about aquifer geometry. In general, spring hydrographs are a function of both system geometry and recharge. However, the majority of prior work on storm pulses through karst has not studied the effect of recharge on spring hydrographs. To examine the relative importance of geometry and recharge, we break karstic aquifers into elements according to the manner of their response to transient flow and demonstrate that each element has a characteristic response timescale. These fundamental elements are full pipes, open channels, reservoir/constrictions, and the porous matrix. Taking the ratio of the element timescale with the recharge timescale produces a dimensionless number, g, that is used to characterize aquifer response to a storm event. Using sets of simulations run with randomly selected element parameters, we demonstrate that each element type has a critical value of g below which the shape of the spring hydrograph is dominated by the shape of the recharge hydrograph and above which the spring hydrograph is significantly modified by the system geometry. This allows separation of particular element/storm pairs into recharge-dominated and geometry-dominated regimes. While most real karstic aquifers are complex combinations of these elements, we draw examples from several karst systems that can be represented by single elements. These examples demonstrate that for real karstic aquifers full pipe and open channel elements are generally in the recharge-dominated regime, whereas reservoir/constriction elements can fall in either the recharge-or geometry-dominated regimes.

Water Resources Research, 1996

In west central Florida, groundwater samples were collected along flow paths in the unconfined up... more In west central Florida, groundwater samples were collected along flow paths in the unconfined upper Floridan aquifer that cross the inland, freshwater recharge area and the coastal discharge area. A groundwater flow and solute transport model was used to evaluate groundwater ...

Water Resources Research, 2011

Previous studies, motivated by understanding water quality, have explored the mechanisms for heat... more Previous studies, motivated by understanding water quality, have explored the mechanisms for heat transport and heat exchange in surface streams. In karst aquifers, temperature signals play an additional important role since they carry information about internal aquifer structures. Models for heat transport in karst conduits have previously been developed; however, these models make different, sometimes contradictory, assumptions. Additionally, previous models of heat transport in karst conduits have not been validated using field data from conduits with known geometries. Here we use analytical solutions of heat transfer to examine the relative importance of heat exchange mechanisms and the validity of the assumptions made by previous models. The relative importance of convection, conduction, and radiation is a function of time. Using a characteristic timescale, we show that models neglecting rock conduction produce spurious results in realistic cases. In contrast to the behavior of surface streams, where conduction is often negligible, conduction through the rock surrounding a conduit determines heat flux at timescales of weeks and longer. In open channel conduits, radiative heat flux can be significant. In contrast, convective heat exchange through the conduit air is often negligible. Using the rules derived from our analytical analysis, we develop a numerical model for heat transport in a karst conduit. Our model compares favorably to thermal responses observed in two different karst settings: a cave stream fed via autogenic recharge during a snowmelt event, and an allogenically recharged cave stream that experiences continuous temperature fluctuations on many timescales.

Mathematical Geology, 2005

Within carbonate systems, the working hypothesis suggests that when a conduit is flooded fluid an... more Within carbonate systems, the working hypothesis suggests that when a conduit is flooded fluid and solute migrate from the conduit into the matrix. This flux of fluid and solute into the matrix creates a reservoir that can be slowly released once the flooding recedes. Although hypothesized, these fluxes have never been measured. To quantify the distance that a fluid and solute would move into a matrix, the fluxes of fluid and solute from a conduit into a matrix were simulated for nine different carbonate aquifer systems. Two independent numerical approaches were used to simulate (1) fluid flux into the matrix and (2) solute flux into the matrix during a flooding event. When flooding occurs within the conduit, the volume of water transported into and stored in the matrix with a high porosity and high hydraulic conductivity (Floridan Aquifer) was less than 0.34 m 3 along a 1 m length of conduit, resulting in a penetration depth of 7.2 × 10 −2 m into the matrix. In a low porosity and low hydraulic conductivity matrix (Ozark Plateau), the volume of water transported into and stored in the matrix was less than 6.85 × 10 −5 m 3 along a 1 m length of conduit, resulting in a penetration depth of 2.0 × 10 −4 m into the matrix. Simulated solute flow shows that less than 0.1% of the solute moves in to the matrix. The two approaches demonstrate that during high flow conditions fluid and solute are forced through the conduits, with very little moving into the carbonate matrix. Once the fluid and solute enter a conduit and are moving, they will remain in the conduit until they are discharged at an outlet. Thus, a carbonate matrix does not become a reservoir for solute and fluid during a high-flow event.

Acta Carsologica, 2013

Hidrogrami so vsota procesov in reakcij v kraškem zaledju izvira. članek nudi kratek pregled upor... more Hidrogrami so vsota procesov in reakcij v kraškem zaledju izvira. članek nudi kratek pregled uporabe hidrogramov pri določitvi notranje strukture kraškega vodonosnika, izboljšanju modelov napajanja in praznenja ter določanja hidrodinamičnih parametrov kraškega zaledja. Pri tem uporabimo podatke iz kraškega izvira Devils Icebox. V primeru tega izvira hidrogrami ne povedo veliko o notranji strukturi vodonosnika, zato pa več o napajanju zaledja. Model polnjenja in praznenja vodono snika ni vrnil vhodnih podatkov iz katerih smo določili model ske parametre in je neuporaben za napovedovanje. Uporaba principa ohranitve mase za določanje hidrodinamičnih parame trov, je dober pristop, a so v našem primeru manjkali nekateri ključni podatki. Kraški hidrologi potrebujejo več kvantitativnih podatkov sledenj in dolge časovne nize podatkov o dotoku in iztoku z visoko časovno ločljivostjo.

Journal of Hydrology, 1998

In aquifers containing large voids, such as karst aquifers with caves or basaltic aquifers with l... more In aquifers containing large voids, such as karst aquifers with caves or basaltic aquifers with lava tubes, hydrographs at wells or springs are used to analyze the structure and response of the hydrogeological system. Numerical modeling of hydrograph response is commonly based on either inverse techniques or postulated flow geometries. However, the range of mechanisms for generating hydrograph responses have not been fully investigated. Physical modeling of these complex non-Darcian systems permits better understanding of the storm responses that conduit systems may generate. Using a numerical model of conduit flow systems which incorporates turbulent flow, some of the mechanisms that can alter storm pulses were investigated by treating them as combinations of pipes that connect reservoirs. The results indicate that the response of a conduit-flow aquifer can range from what has been called 'diffuse' or 'steady' to 'conduit' or 'flashy', without employing a diffusive component. A full range of behavior can be the result of changes from phreatic to epiphreatic conditions in a conduit, changes in conduit geometry, or multiple springs draining the same system. The results provide a quantitative tool to assess spring and well hydrographs, and illustrate mechanisms that can generate observed responses, which have previously been qualitatively interpreted.

Journal of Hydrology, 2004

The primary geomorphic process active in the development of karst stream systems is generally reg... more The primary geomorphic process active in the development of karst stream systems is generally regarded as bedrock dissolution. However, physical erosional processes may also be an important geomorphic agent in karst development. The objectives of this study were to determine the sediment transport threshold in two fluviokarst streams. The source of the sediment was internal to the karst basins. The approach used was to calculate basal and critical shear stresses from streams in two karst systems to determine if, and how frequently, storm-induced flows are capable of mobilizing stream sediment. The fluviokarst systems investigated as a part of this research are capable of transporting 50-85% of their stream substrates during bankfull discharge conditions. Based on the discharge and precipitation frequency, stream flows capable of entraining d 50 and d 85 particles occur at intervals of 2.4 and 11.7 months (0.98 yr), respectively. Thus, the sediment transport threshold in fluviokarst streams is exceeded by relatively common discharge events.

Journal of Hydrology, 2006

Questions about the importance of conduit geometry and about the values of hydraulic parameters i... more Questions about the importance of conduit geometry and about the values of hydraulic parameters in controlling groundwater flow and solute transport through karstic aquifers have remained largely speculative. One goal of this project was to assess the role that the conduit geometry and the hydraulic parameters have on controlling transport dynamics within karstic aquifers. The storm water management model (SWMM) was applied to the Devil's Icebox-Connor's Cave System in central Missouri, USA. Simulations with incremental changes to conduit geometry or hydraulic parameters were performed with the output compared to a calibrated baseline model. Ten percent changes in the length or width of a conduit produced statistically significant different fluid flow responses. The model exhibited minimal sensitivity to slope and infiltration rates; however, slight changes in Manning's roughness coefficient can highly alter the simulated output. Traditionally, the difference in flow dynamics between karstified aquifers and porous media aquifers has led to the idea that modeling of karst aquifers is more difficult and less precise than modeling of porous media aquifers. When evaluated against models for porous media aquifers, SWMM produced results that were as accurate (10% error compared to basecase). In addition, SWMM has the advantage of providing data about local flow. While SWMM may be an appropriate modeling technique for some karstic aquifers, SWMM should not be viewed as a universal solution to modeling karst systems.