Effect of the Capillary Fringe on Steady-State Water Tables in Drained Lands. II: Effect of an Underlying Impermeable Bed
Publication: Journal of Irrigation and Drainage Engineering
Volume 139, Issue 4
Abstract
A tension-saturated capillary fringe above the water table in drained lands gives rise to lower water tables than would occur in its absence. Results of a conformal mapping solution for the flow from uniform steady rainfall rates on the soil surface to deep drains installed above an impermeable bed when the soil above the drains is wholly tension-saturated show that the effect on the water table is greater the nearer the drain is to the impermeable floor. The effect becomes less with increasing rainfall rate. For the very deep tension-saturated soils assumed in the analysis (that implies a very large negative value for the air-entry pressure for the soil), the results obtained give lower bounds for the water-table heights in real soils with finite air-entry values that lie between the calculated ones and those obtained by theory neglecting a capillary fringe.
Get full access to this article
View all available purchase options and get full access to this article.
References
Childs, E. C. (1945). “The water table, equipotentials and streamlines in drained lands: III.” Soil Sci., 59(5), 405–415.
Childs, E. C. (1959). “A treatment of the capillary fringe in the theory of drainage.” J. Soil Sci., 10(1), 83–100.
Childs, E. C. (1960). “A treatment of the capillary fringe in the theory of drainage: II. Modifications due to an impermeable sub-stratum.” J. Soil Sci., 11(2), 293–304.
Collis-George, N., and Youngs, E. G. (1958). “Some factors determining water-table heights in drained homogeneous soils.” J. Soil Sci., 9(2), 332–338.
Luthin, J. N., ed. (1957). Drainage of agricultural lands, American Society of Agronomy, Madison, WI.
Skaggs, R. W., van Schilfgaarde, J., eds. (1999). Agricultural drainage, American Society of Agronomy, Madison, WI.
van Deemter, J. J. (1950). Theoretische en numericke behandling van ontwaterings-en infiltratie-stromingsproblemen.” Versl. Landb. Onderz., 56(7), 1–67 (in Dutch).
van Schilfgaarde, J., ed. (1974). Drainage for agriculture, American Society of Agronomy, Madison, WI.
Youngs, E. G. (1983). “The contribution of physics to land drainage.” J. Soil Sci., 34(1), 1–21.
Youngs, E. G. (1984). “Developments in the physics of land drainage.” J. Agric. Eng. Res., 29(2), 167–175.
Youngs, E. G. (1985). “A simple drainage equation for predicting water-table drawdowns.” J. Agric. Eng. Res., 31(4), 321–328.
Youngs, E. G. (1991). “A note on the power-law land-drainage equation for deep soils.” J. Agric. Eng. Res., 49, 161–163.
Youngs, E. G. (2012). “Effect of the capillary fringe on steady-state water tables in drained lands.” J. Irrig. Drain. Eng., 138(9), 809–814.
Information & Authors
Information
Published In
Journal of Irrigation and Drainage Engineering
Volume 139 • Issue 4 • April 2013
Pages: 309 - 312
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Oct 4, 2011
Accepted: Aug 8, 2012
Published online: Aug 20, 2012
Published in print: Apr 1, 2013
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.