Approximate Form of Green‐Ampt Infiltration Equation
Publication: Journal of Irrigation and Drainage Engineering
Volume 120, Issue 1
Abstract
We develop an approximation of the Green‐Ampt infiltration equation by using the first two terms of a Taylor‐series expansion of the equation. The resulting approximate equation is in the form of the Philip's equation, with an added term to account for the error in the approximation. The Taylor‐series approximation is compared with Li et al.'s 1976 quadratic approximation for the case of constant rainfall with variable time to ponding. The maximum error for the new approximation is about 3.5%; and the maximum error for the quadratic approximation is about 8%. For a range of values of the ratio of infiltrated depth to capillary potential of 0.1 to 150 the approximation of the Taylor series fits the Green‐Ampt infiltrated depth more closely than the quadratic approximation. It is shown that the approximation of the Taylor series gives less error than the quadratic approximation for coarser textured soils.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Li, R. M., Stevens, M. A., and Simons, D. B. (1976). “Solutions to Green‐Ampt infiltration equation.” J. Irrig. and Drain. Div., ASCE, 102(2), 239–248.
2.
Mein, R. G., and Larson, C. L. (1973). “Modeling infiltration during steady rain.” Water Resour. Res., 9(2), 384–394.
3.
Philip, J. R. (1957). “The theory of infiltration: 4. Sorptivity and algebraic infiltration equations.” Soil Sci., 84, 257–264.
4.
Rawls, W. J., Brakensiek, D. L., and Saxton, K. E. (1982). “Estimation of soil water properties.” Trans. ASAE Spec. Ed.; Soil and Water, 25, 1316–1320.
5.
Rawls, W. J., Stone, J. J., and Brakensiek, D. L. (1989). “Chapter 4: infiltration.” “USDA‐Water Erosion Prediction Project: Hillslope Profile Model Documentation,” NSERL Rep. No. 2, L. J. Lane and M. A. Nearing, eds., National Soil Erosion Research Laboratory, USDA‐ARS, West Lafayette, Ind., 4.1–4.12.
6.
“USDA‐Water Erosion Prediction Project: hillslope profile model documentation.” (1989). NSERL Rep. No. 2, L. J. Lane and M. A. Nearing, eds., National Soil Erosion Research Laboratory, USDA‐ARS, West Lafayette, Ind.
Information & Authors
Information
Published In
Copyright
Copyright © 1994 American Society of Civil Engineers.
History
Received: Aug 20, 1992
Published online: Jan 1, 1994
Published in print: Jan 1994
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.