Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China: Soil CO2 and dilution effects

Liu, Zaihua; Li, Qiang; Sun, Hailong; Wang, Jinliang

doi:10.1016/j.jhydrol.2007.01.034

Cited by 150 publications

(117 citation statements)

References 20 publications

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“…A possible explanation for the CO 2 trend is that baseflow water in the stream has lower CO 2 levels due to gas loss compared to water stored in low permeability zones that will be mobilised during flood events. The CO 2 trends are distinctly different from other studies where a decrease of the CO 2 concentration occurred during flood events (Liu et al, 2004(Liu et al, , 2007 or a CO 2 increase was observed during the recession limb of the hydrograph rather than at the beginning of the flood peak as in our study (Vesper and White, 2004). The different CO 2 behaviour at other sites may due to the higher importance of concentrated infiltration at these sites compared to our site.…”

Section: Origin and Behaviour Of Cocontrasting

confidence: 99%

“…In these studies CO 2 concentration typically varied between 2% and 5 vol.% CO 2 . Other studies focussed on dissolved CO 2 concentrations in karst (Liu et al, 2004;Vesper and White, 2004) and epikarst (Liu et al, 2007) springs. In case of concentrated infiltration via sinkholes, CO 2 concentrations can decrease during heavy rainfall due to a dilution effect (Liu et al, 2004(Liu et al, , 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Other studies focussed on dissolved CO 2 concentrations in karst (Liu et al, 2004;Vesper and White, 2004) and epikarst (Liu et al, 2007) springs. In case of concentrated infiltration via sinkholes, CO 2 concentrations can decrease during heavy rainfall due to a dilution effect (Liu et al, 2004(Liu et al, , 2007. However, during low intensity rainfall and dispersed infiltration, the effect of flushing CO 2 -rich soils can dominate over dilution and the CO 2 level increases in springs (Liu et al, 2007;Vesper and White, 2004) or in diffuse flow fractured media (Liu et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In case of concentrated infiltration via sinkholes, CO 2 concentrations can decrease during heavy rainfall due to a dilution effect (Liu et al, 2004(Liu et al, , 2007. However, during low intensity rainfall and dispersed infiltration, the effect of flushing CO 2 -rich soils can dominate over dilution and the CO 2 level increases in springs (Liu et al, 2007;Vesper and White, 2004) or in diffuse flow fractured media (Liu et al, 2004). For example in a karst springs in Kentucky/Tennessee (Vesper and White, 2004), dissolved CO 2 concentrations increased after the maximum discharge was reached during storm flow, which was explained by diffuse infiltration through CO 2 -rich soils lagging behind quickflow from a sinkhole.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Radon and CO2 as natural tracers to investigate the recharge dynamics of karst aquifers

Savoy¹,

Surbeck²,

Hunkeler³

2011

Journal of Hydrology

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Keywords:Karst hydrogeology Soil Epikarst Radon Carbon dioxide Unsaturated zone s u m m a r y This study investigated the use of radon ( 222 Rn), a radioactive isotope with a half-life of 3.8 days, and CO 2 as natural tracers to evaluate the recharge dynamics of karst aquifer under varying hydrological conditions. Dissolved 222 Rn and carbon dioxide (CO 2 ) were measured continuously in an underground stream of the Milandre test site, Switzerland. Estimated soil water 222 Rn activities were higher than baseflow 222 Rn activities, indicating elevated 222 Rn production in the soil zone compared to limestone, consistent with a 226 Ra enrichment in the soil zone compared to limestone. During small flood events, 222 Rn activities did not vary while an immediate increase of the CO 2 concentration was observed. During medium and large flood events, an immediate CO 2 increase and a delayed 222 Rn activity increase to up to 4.9 Bq/L and 11 Bq/L, respectively occurred. The detection of elevated 222 Rn activities during medium and large flood events indicate that soil water participates to the flood event. A soil origin of the 222 Rn is consistent with its delayed increase compared to discharge reflecting the travel time of 222 Rn from the soil to the saturated zone of the system via the epikarst. A three-component mixing model suggested that soil water may contribute 4-6% of the discharge during medium flood events and 25-43% during large flood events. For small flood events, the water must have resided at least 25 days below the soil zone to explain the background 222 Rn activities, taking into account the half-life of 222 Rn (3.8 days). In contrast to 222 Rn, the CO 2 increase occurred simultaneously with the discharge increase. This observation as well as the CO 2 increase during small flood events, suggests that the elevated CO 2 level is not due to the arrival of soil water as for 222 Rn. A possible explanation for the CO 2 trend is that baseflow water in the stream has lower CO 2 levels due to gas loss compared to water stored in low permeability zones. During flood event, the stored water is more rapidly mobilised than during baseflow with less time for gas loss. The study demonstrates that 222 Rn and CO 2 provides value information on the dynamics of groundwater recharge of karst aquifer, which can be of high interest when evaluating the vulnerability of such systems to contamination.

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Section: Origin and Behaviour Of Cocontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Radon and CO2 as natural tracers to investigate the recharge dynamics of karst aquifers

Savoy¹,

Surbeck²,

Hunkeler³

2011

Journal of Hydrology

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“…In regions where the ground water lies at shallow depths and where there is much localized recharge through sinking streams, the springs often show considerable seasonal variation in their physical-chemical characteristics. On the other hand, springs originating from higher depths showing possible fluctuations in discharge tend to maintain their physical-chemical characteristics constant in time (Liu et al, 2007;Shuster and White, 1971). …”

Section: Introductionmentioning

confidence: 99%

Analysis of temporal hydrochemical and isotopic variations in spring waters of Eastern Peloponnesus (Greece)

Matiatos¹,

Αλεξόπουλος²

2017

geosociety

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Karst water resources in a changing world: Review of hydrological modeling approaches

et al. 2014

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Karst regions represent 7–12% of the Earth's continental area, and about one quarter of the global population is completely or partially dependent on drinking water from karst aquifers. Climate simulations project a strong increase in temperature and a decrease of precipitation in many karst regions in the world over the next decades. Despite this potentially bleak future, few studies specifically quantify the impact of climate change on karst water resources. This review provides an introduction to karst, its evolution, and its particular hydrological processes. We explore different conceptual models of karst systems and how they can be translated into numerical models of varying complexity and therefore varying data requirements and depths of process representation. We discuss limitations of current karst models and show that at the present state, we face a challenge in terms of data availability and information content of the available data. We conclude by providing new research directions to develop and evaluate better prediction models to address the most challenging problems of karst water resources management, including opportunities for data collection and for karst model applications at so far unprecedented scales.

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Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China: Soil CO2 and dilution effects

Cited by 150 publications

References 20 publications

Radon and CO2 as natural tracers to investigate the recharge dynamics of karst aquifers

Radon and CO2 as natural tracers to investigate the recharge dynamics of karst aquifers

Analysis of temporal hydrochemical and isotopic variations in spring waters of Eastern Peloponnesus (Greece)

Karst water resources in a changing world: Review of hydrological modeling approaches

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