Thermal damping and retardation in karst conduits

Luhmann, A. J.; Covington, M. D.; Myre, Joseph M.; Perne, Matija; Jones, Stephen; Alexander, E. Calvin; Saar, Martin O.

doi:10.5194/hess-19-137-2015

Cited by 30 publications

(36 citation statements)

References 31 publications

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“…Nevertheless, it has limited value in interpreting karst aquifer structures (Jeannin & Sauter, 1998) and identifying the contributions of event and pre-event water. The non-conservative nature of water temperature facilitates insights into conduit size and the damping and retardation in porous media via an analysis of input and output thermographs (Birk, Wagner, & Mayaud, 2014;Covington, Luhmann, Gabrovek, Saar, & Wicks, 2011;Covington, Luhmann, Wicks, & Saar, 2012;Luhmann et al, 2012;Luhmann et al, 2015). However, reliable identification of the hydrological functions from input and output thermographs needs to integrate information on heat exchange within karst conduits that may introduce a retardation in the residence times (Luhmann et al, 2015).…”

Section: Benefits Of An Integrated Approachmentioning

confidence: 99%

“…The non-conservative nature of water temperature facilitates insights into conduit size and the damping and retardation in porous media via an analysis of input and output thermographs (Birk, Wagner, & Mayaud, 2014;Covington, Luhmann, Gabrovek, Saar, & Wicks, 2011;Covington, Luhmann, Wicks, & Saar, 2012;Luhmann et al, 2012;Luhmann et al, 2015). However, reliable identification of the hydrological functions from input and output thermographs needs to integrate information on heat exchange within karst conduits that may introduce a retardation in the residence times (Luhmann et al, 2015). Comparison of the temporary variation of isotopic values in rainfall with the observed variability in karst spring waters allows not only quantification of mixing processes in discharge as shown in our study but also quantification of transit time distributions (Hu, Chen, Nie, & Wang, 2015) and determination of groundwater ages.…”

Section: Benefits Of An Integrated Approachmentioning

confidence: 99%

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Characterizing the heterogeneity of karst critical zone and its hydrological function: An integrated approach

Chen

Zhang

Soulsby

et al. 2018

Hydrological Processes

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Spatial heterogeneity in the subsurface of karst environments is high, as evidenced by the multiphase porosity of carbonate rocks and complex landform features that result in marked variability of hydrological processes in space and time. This includes complex exchange of various flows (e.g., fast conduit flows and slow fracture flows) in different locations. Here, we integrate various “state‐of‐the‐art” methods to understand the structure and function of this poorly constrained critical zone environment. Geophysical, hydrometric, and tracer tools are used to characterize the hydrological functions of the cockpit karst critical zone in the small catchment of Chenqi, Guizhou Province, China. Geophysical surveys, using electrical resistivity tomography (ERT), inferred the spatial heterogeneity of permeability in the epikarst and underlying aquifer. Water tables in depression wells in valley bottom areas, as well as discharge from springs on steeper hillslopes and at the catchment outlet, showed different hydrodynamic responses to storm event rainwater recharge and hillslope flows. Tracer studies using water temperatures and stable water isotopes (δD and δ18O) could be used alongside insights into aquifer permeability from ERT surveys to explain site‐ and depth‐dependent variability in the groundwater response in terms of the degree to which “new” water from storm rainfall recharges and mixes with “old” pre‐event water in karst aquifers. This integrated approach reveals spatial structure in the karst critical zone and provides a conceptual framework of hydrological functions across spatial and temporal scales.

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Section: Benefits Of An Integrated Approachmentioning

confidence: 99%

Section: Benefits Of An Integrated Approachmentioning

confidence: 99%

Characterizing the heterogeneity of karst critical zone and its hydrological function: An integrated approach

Chen

Zhang

Soulsby

et al. 2018

Hydrological Processes

View full text Add to dashboard Cite

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“…In order for the thermal signal of a recharge event to reach the water table via vertical flow in a fracture, the thermal penetration length must be approximately equal to or greater than the depth to the water table (e.g., Covington et al 2012). The thermal constants (density, heat capacity, and thermal diffusivity; Table 2) of water and limestone were taken from the literature (Luhmann et al 2015). The hydraulic gradient was assumed to be 1 to simulate a vertical fracture.…”

Section: Thermal Penetration Analysismentioning

confidence: 99%

“…It is also possible to estimate the conduit hydraulic diameter using estimates of the damping or retardation of a thermal pulse (Luhmann et al 2015). The thermal transmission factor, F , is given by:…”

Section: Thermal Damping Analysismentioning

confidence: 99%

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Effects of Changing Meteoric Precipitation Patterns on Groundwater Temperature in Karst Environments

Brookfield¹,

Macpherson

Covington

2016

Groundwater

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Climate predictions indicate that precipitation patterns will change and average air temperatures will increase across much of the planet. These changes will alter surface water and groundwater temperatures which can significantly affect the local and regional environment. Here, we examine the role of precipitation timing in changes to groundwater temperature in carbonate-karst aquifers using measured groundwater level and temperature data from the Konza Prairie Long-Term Ecological Research Site, Kansas. We demonstrate that shifts to increased cool-season precipitation may mitigate the increases in groundwater temperature produced by increases in average annual air temperature. In karst, the solution-enlarged conduits allow faster and focused recharge, and the recharge-event temperature can strongly influence the groundwater temperature in the aquifer. Our field data and analysis show that predictions of future groundwater conditions in karst aquifers need to consider changes in precipitation patterns, in addition to changes to average annual air temperature.

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Shallow groundwater temperature patterns revealed through a regional monitoring well network

Smith,

O'Sullivan,

Kennedy

et al. 2023

Hydrological Processes

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Groundwater temperature is a critical control on groundwater quality, geothermal system efficiency and ecosystem dynamics in receiving surface waters. Despite the known importance of groundwater temperature, there is a lack of dedicated aquifer thermal monitoring across spatial and temporal scales. Pressure transducers and other sensors installed in groundwater monitoring well networks often record temperature as a secondary function, but these comprehensive groundwater temperature data sets are seldom analysed. In this study, we analysed seasonal, interannual and spatial patterns of shallow groundwater temperatures from a regional groundwater monitoring network in Nova Scotia, Canada and compared these subsurface temperature data to air temperature data from nearby climate stations using linear regressions and Fourier analysis. The results showed that seasonal groundwater temperatures were damped (with seasonal amplitudes 3.6%–42% of air temperature amplitudes) and lagged (phase shifted 43–145 days) compared to air temperature, with notable year‐to‐year variations in both damping and lagging. Results also highlighted the role of snowpack thickness on the lowest mean monthly groundwater temperatures. Given potential impacts of climate change, land cover change, urbanization and geothermal energy development on groundwater temperatures, we encourage water authorities and regulators to begin or enhance aquifer thermal monitoring and provide guidance for capitalizing on existing monitoring well infrastructure to track temperature dynamics and changes.

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Thermal damping and retardation in karst conduits

Cited by 30 publications

References 31 publications

Characterizing the heterogeneity of karst critical zone and its hydrological function: An integrated approach

Characterizing the heterogeneity of karst critical zone and its hydrological function: An integrated approach

Effects of Changing Meteoric Precipitation Patterns on Groundwater Temperature in Karst Environments

Shallow groundwater temperature patterns revealed through a regional monitoring well network

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