Abstract
Estimate values for transport parameters are reported for the conditions of a volcanic fractured phreatic aquifer in Costa Rica. Three salt-tracer tests performed under natural gradient conditions were interpreted with the aid of single porosity advective-dispersive analytical solutions for pulse and instantaneous injections. Field breakthrough curves showed a clear asymmetric shape, very common of fractured systems. Applied analytical solutions allowed to gain insights in the understanding of the transport processes involved during solute transport in fractured systems, but did not allowed for the reproduction of the observed asymmetric shape. Flow parameters were also obtained (saturated hydraulic conductivity; effective porosity and Darcy´s flux). The calculated values are within the range of values reported in the literature for fractured aquifers.References
ALVARADO, G. & SALANI, F., 2004: Tefroestratigrafìa (40 000 - 2000 A.P) en el sector Caribe de los volcanes Barva, Congo y Hule, Cordillera Central, Costa Rica.- Rev. Geol. Amér. Central, 30: 59-72.
CUSTODIO, E. & LLAMAS, M., 1983: Hidrología subterránea.- 2350 págs. Ediciones Omega. Barcelona.
ESCUDER, R., FRAILE, J., JORDANA, S., RIBERA, F., SÁNCHEZ-VILA, X. & VÁZQUEZ-SUÑE, E., 2009: Transporte de solutos en aguas subterráneas y ensayos de trazadores.- 768 págs. Edit. Escuder, R., Fraile, J., Jordana, S., Ribera, F., Sánchez-Vila, X. & Vázquez-Suñé. En Hidrogeología, conceptos básicos de hidrología subterránea.-FCIHS, 378-425.
FETTER, C.W., 1993: Contaminant hydrogeology.- 458 págs. Prentice Hall, Nueva Jersey.
KREFT, A. & ZUBER, A., 1978: On the physical meaning of the dispersion equation and its solutions for different initial and boundary conditions.- Chem. Engin. Sci. 33: 1471-1480.
LAPIDUS, L. & AMUNDSON, N. R., 1952: Mathematics of adsorption in beds. VI. The effects of longitudinal diffusion in ion exchange and chromatographic columns.- J. Phys. Chem. 56: 984-988.
LOSILLA, M., RODRÍGUEZ, H., SCHOSINSKY, G., STIMSON, J., BETHUNE, D., 2001: Características hidrogeológicas de la región centroamericana.- En: Mora, R. & Rojas, S. (comps): Los acuíferos volcánicos y el desarrollo sostenible en América Central.- Edit. U.C.R., San José: 33-178.
MALOSZEWSKI, P. & ZUBER, A., 1990: Mathematical modelling of tracer behaviour in short-term experiments in fissured rocks.- Water Resources Res. 26(7): 1517-1528.
MANZUR, C. I. & KAUFMAN, R. I., 1962: Dewatering. En: Leonards, G.A. (ed.). Foundation Engineering.- Mc Graw - Hill Book Co, 241-350.
PTAK, TH., PIEPENBRINK, M., MARTAC, E., 2004: Tracer test for the investigation of heterogeneous porous media and stochastic modelling of flow and transport- a review of some recent developments.- Journal of hydrology 294 (2004): 122-163.
SAUTY, J.P., 1980: An Analysis of Hydrodispersive Transfer in Aquifers.- Water Resources Research. 16 (1):145-158.
TSANG, D.H., FRIND, E.O., & SUDICKY, E. A., 1981: Contaminant transport in fractured porous media: analytical solution for a single fracture.- Water Resources Research. 17 (3): 555-564.
VAN GENUCHTEN, M., 1981: Non-Equilibrium transport parameters from miscible displacement experiments.- 88 págs. U.S. Salinity Laboratory. Department of Agriculture Science and Education Administration, California. [Reporte de investigación No 119]
VARGAS, A. & FERNÁNDEZ, F., 2002: Aspectos hidrogeológicos en el sitio del embalse Cipreses, P.H. Cariblanco y aplicaciones de trazadores en agua subterránea.- Rev. Geól. Amér. Central. 27: 133-142.