Abstract
To study the complex flow of water in soils, the concepts of the residence time theory have been applied. Tritiated water (HTO) was used as a tracer in humus to obtain experimental response curves for a laboratory system and a theoretical flow model was constructed and fitted to the data. The purpose of this work was to establish a flow model for a subsequent ion exchange model (Part II of this paper). Our utlimate goal is to apply the experimental techniques and the models developed to the study of natural systems.
Tracer response curves have been obtained both with input in the form of a step function and as a short pulse. The pulse response technique seems to give the best results in terms of a smooth residence time distribution (RTD) curve.
The observed RTD-curves show that the commonly used simple axial dispersion model will not give a good description of the flow. The distributions are so skewed that a dispersion model with a non-uniform velocity field would have to be applied. The models applied are a further development of the well known tanks-in-series models and are mathematically and conceptually simplified versions of such dispersion models.
The results indicate that the flow of water in a soil system can be treated as two regimes: One is the rapid throughflow in large to medium sized pores, the other is the very slow (passive) flow in smaller pores, representing a different type of flow.
The model developed generally simulates the observed RTD-functions closely by treating the flow in terms of these two separate flow regimes.
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References
Brandes, M., Chan, H. T., and Cheng, W. W.: 1975,Movement of Tracers through Soil, Research Report No. S55, Ministry of Environment, Ontario, Canada, 28 pp.
Brustad, K., Christophersen, N., Njøs, A., and Seip, H. M.: 1979, ‘Simulation of Flow Patterns and Ion exchange Processes in a Series of Soil Percolation Experiments’. SNSF-project IR 41/79. 89 pp.
Christophersen, N., Njøs, A., and Seip, H. M.: 1980,Water, Air Soil Pollut. (in press).
Corey, J. C. and Horton, J. H.: 1968,Soil Sci. Soc. Amer. Proc. 32, 471.
Deans, H. A.: 1963,Soc. Pet. Eng. J.,3, 49.
De Wit, C. T. and van Keulen, H.: 1972, ‘Simulation of transport Processes in Soils’. Wageningen Centre for Agricultural Publishing and Documentation, 1972. 100 pp.
Frissel, M. J., Poelstra, P., Harmsen, K., and Bolt, G. H.: 1974, in ‘Isotope and Radiation Techniques in Soil. Physics and Irrigation Studies 1973’, Int. Atomic Energy Agency, Vienna: 145–148.
Heemstra, R. J., Watkins, J. W., and Armstrong, F. E.: 1961,Nucleonics 19, 92.
Himmelblau, D. M. and Bischoff, K. B.: 1968,Process Analysis and Simulation. Deterministic Systems, John Wiley: 348 pp.
Njøs, A.: 1978, ‘Strømning av vann og løste stoffer gjennom jord, spesielt jordsmonn med råhumus’. SNSF-project, IR 39/78, 91 pp.
Pilgrim, D. H.: 1976,Water Res. Res.,12 no. 3, p. 487.
Pilgrim, D. H.: 1978,J. Hydrol.,36, p. 47.
Quisenberry, V. L. and Phillips, R. E.: 1976,Soil Sci. Soc. Am. J.,40, 484.
Spielman, L. A., Briere, F.: 1971, Non-Equilibrium Systems in Natural Water Chemistry. Advances in Chemistry Series no. 106. Amer. Chem. Soc., Wash. p. 174.
Van Genuchten, M. Th. and Cleary, R. W.: 1979, in Soil Chemistry. B. Physico-Chemical Models (ed. Bolt, G. H.) Elsevier Sci. Publ. p. 349.
Zimmermann, U., Münnich, K. O., and Roether, W.: 1966,Science 152, 346.
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Brustad, K., Njøs, A. Simulation of flow patterns and ion-exchange in soil percolation experiments. Water Air Soil Pollut 13, 459–472 (1980). https://doi.org/10.1007/BF02191847
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DOI: https://doi.org/10.1007/BF02191847