Tracer Investigations of the Nature and Structure of Subsurface Voids in Mildly Karstic Aquifers: an Example from the English Chalk

Maurice, Louise; Atkinson, T. C.; Barker, John A.; Williams, A. T.; Farrant, Andrew; Gallagher, A.J.

doi:10.1007/978-3-642-12486-0_21

Cited by 2 publications

(4 citation statements)

References 10 publications

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“…By contrast, in mildly karstified areas, even if the flow velocity reached several kilometers per day, the tracer recovery was only 25-35% [15]. Maurice considered that the significant attenuation was probably due to the dispersion of tracers from the main conduit flow paths into small voids [15]. In our test, although the study area is a well-developed karst system, the flow velocity is relatively lower compared to that of other karst areas discussed above.…”

Section: Tracer Velocity and Recoverymentioning

confidence: 51%

“…Relatively rapid flow and low tracer recovery indicate the high storage percentage in the karst. Some researchers conjectured that there was limited connected conduit network in the paths where the tracers passed [1,15,22].…”

Section: Conduit Characteristics Of Receiving Springsmentioning

confidence: 99%

“…By contrast, in the mildly karstified aquifer in Chalk, the tracer velocity can reach 5 km/day, which is as rapid as that of the highly karstic aquifers. Maurice considered that this conduit in Chalk had many fissures and voids with limited connectivity [15]. The karst conduit for every springs * "+" refers to "positive" in fracture development.…”

Section: Tracer Velocity and Recoverymentioning

confidence: 99%

“…Several tracer tests were also carried out in the Xiangxi River Basin of southern China, and the maximum tracer recovery was 64%. By contrast, in mildly karstified areas, even if the flow velocity reached several kilometers per day, the tracer recovery was only 25-35% [15]. Maurice considered that the significant attenuation was probably due to the dispersion of tracers from the main conduit flow paths into small voids [15].…”

Section: Tracer Velocity and Recoverymentioning

confidence: 99%

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Characterization of Karst Conduit Network Using Long-Distance Tracer Test in Lijiang, Southwestern China

Cen

et al. 2018

Water

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The Ancient City in Lijiang of southwestern China was endowed as World Cultural Heritage by UNESCO, and the karst springs located in Black Dragon Pool are its main water source. However, the springs have dried up several times in recent years, which caused serious damages to the landscape as well as the city water supply. Triggered by the dried-up event in Black Dragon Pool, a long-distance artificial tracer test up to 17 km was employed to investigate the karst conduit network distributing in the study area. Based on the tracer concentration breakthrough curves (BTCs), the hydraulic connection from the same injection point (located in a giant depression named the Jiuzi Sea) to the springs on both sides of the topography watershed was proven, and the conduit structure was discussed. According to the characteristics of BTCs and considering the low tracer concentration and tracer recovery, a conceptual structure of leaky reservoir with threshold effect above a certain groundwater level was established to interpret why the springs in Black Dragon Pool dried up several times in history, but those in the Ancient City never did. Furthermore, a method of injecting surface water into the Jiuzi Sea to raise the groundwater level up to the height of Black Dragon Pool was proposed to restore the springs. Our study provides insights into the long-distance artificial tracer test, and opens a new avenue for groundwater resource recovery of this Ancient City.

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Section: Tracer Velocity and Recoverymentioning

confidence: 51%

Section: Conduit Characteristics Of Receiving Springsmentioning

confidence: 99%

Section: Tracer Velocity and Recoverymentioning

confidence: 99%

Section: Tracer Velocity and Recoverymentioning

confidence: 99%

See 2 more Smart Citations

Characterization of Karst Conduit Network Using Long-Distance Tracer Test in Lijiang, Southwestern China

Cen

et al. 2018

Water

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The genesis and evolution of karstic conduit systems in the Chalk

Farrant

Maurice

Ballesteros

et al. 2022

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The Upper Cretaceous Chalk Group is renowned as a major aquifer, but the development of secondary porosity due to karstic conduits is poorly understood. Hydrogeological data and evidence from boreholes, sections, and tracer tests indicate that dissolutional conduits occur throughout the Chalk aquifer. Here, we assess the evidence for Chalk karst, and combine it with theoretical models of dissolution and cave formation to produce a conceptual model for the development of karstic conduits. Dissolution due to the mixing of saturated waters of contrasting chemistry along key lithostratigraphical inception horizons form extensive but isolated conduit networks. These form a significant proportion of the secondary porosity and enhance permeability. They prime the aquifer for the development of more integrated conduit networks formed by focussed recharge of unsaturated surface derived water. However, the porous, well-fractured nature of the Chalk means that the time needed to form large integrated cave systems is often longer than timescales of landscape change. Continued landscape evolution and water table lowering halts conduit development before they can enlarge into cave systems except where geological and geomorphological settings are favourable. Groundwater models need to consider the formation of secondary karst permeability as this has a major influence on groundwater flow.

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Tracer Investigations of the Nature and Structure of Subsurface Voids in Mildly Karstic Aquifers: an Example from the English Chalk

Cited by 2 publications

References 10 publications

Characterization of Karst Conduit Network Using Long-Distance Tracer Test in Lijiang, Southwestern China

Characterization of Karst Conduit Network Using Long-Distance Tracer Test in Lijiang, Southwestern China

The genesis and evolution of karstic conduit systems in the Chalk

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