Regional-scale analysis of karst underground flow deduced from tracing experiments: examples from carbonate aquifers in Malaga province, southern Spain

Journal Article · Thu Feb 15 04:00:00 EST 2018 · Hydrogeology Journal

DOI:https://doi.org/10.1007/S10040-017-1638-5· OSTI ID:22780892

Mudarra, M.; Andreo, B.; Torre, B. De la ^[1]

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1. University of Malaga (CEHIUMA), Centre of Hydrogeology (Spain)

Tracer concentration data from field experiments conducted in several carbonate aquifers (Malaga province, southern Spain) were analyzed following a dual approach based on the graphical evaluation method (GEM) and solute transport modeling to decipher flow mechanisms in karst systems at regional scale. The results show that conduit system geometry and flow conditions are the principal factors influencing tracer migration through the examined karst flow routes. Solute transport is mainly controlled by longitudinal advection and dispersion throughout the conduit length, but also by flow partitioning between mobile and immobile fluid phases, while the matrix diffusion process appears to be less relevant. The simulation of tracer breakthrough curves (BTCs) suggests that diffuse and concentrated flow through the unsaturated zone can have equivalent transport properties under extreme recharge, with high flow velocities and efficient mixing due to the high hydraulic gradients generated. Tracer mobilization within the saturated zone under low flow conditions mainly depends on the hydrodynamics (rather than on the karst conduit development), which promote a lower longitudinal advection and retardation in the tracer migration, resulting in a marked tailing effect of BTCs. The analytical advection-dispersion equation better approximates the effective flow velocity and longitudinal dispersion estimations provided by the GEM, while the non-equilibrium transport model achieves a better adjustment of most asymmetric and long-tailed BTCs. The assessment of karst underground flow properties from tracing tests at regional scale can aid design of groundwater management and protection strategies, particularly in large hydrogeological systems (i.e. transboundary carbonate aquifers) and/or in poorly investigated ones.

• OSTI ID: 22780892
• Journal Information: Hydrogeology Journal, Journal Name: Hydrogeology Journal Journal Issue: 1 Vol. 26; ISSN 1431-2174
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ADVECTION
AQUIFERS
CARBONATES
CONCENTRATION RATIO
EXPERIMENTAL DATA
FLOW RATE
GROUND WATER
GROUNDWATER RECHARGE
HYDRODYNAMICS
MIGRATION
REGIONAL ANALYSIS
SPAIN
TAILINGS
TRACER TECHNIQUES
TRANSPORT THEORY
UNDERGROUND