Estimation of the Philip infiltration parameters from rainfall simulation data

TitleEstimation of the Philip infiltration parameters from rainfall simulation data
Publication TypeJournal Article
Year of Publication1986
AuthorsBach L.B, Wierenga P.J, Ward T.J
JournalSoil Science Society of America Journal
Date Published1986
Accession NumberJRN00035
Call Number00445
Keywordsarticle, articles, hydrology,infiltration prediction, infiltration, rate, journal, journals, rainfall simulation, runoff

A new, simple technique for estimating the parameters of the two-term Philip infiltration equation was developed and tested using field-measured data obtained in the northern Chihuahuan desert of New Mexico. The technique simultaneously provided information on the relationship between the Philip equation parameter A, and the field-measured hydraulic conductivity. The equation was reformulated as I - cKf = 1/2St-1/2, where I is the infiltration rate, S the sorptivity, t the time, Kf the field-measured final infiltration rate, and c, a coefficient relating Kf to the Philip parameter A. The final, steady infiltration rate measured in the field was used for the value of Kf. Regressions of (I - cKf) vs. (1/2t-1/2) for values of c between 0 to 1 resulted in optimum values for each treatment along with their corresponding S values. For the soils in this area, values for the coefficient c were somethimes outside the suggested range of 0.33 to 0.67, and were different for each study site. The regression analysis also showed that the value of S can be highly sensitive to changes in c. Using the values of S and c determined by the proposed method, a comparison was made between computed infiltration rates and measured infiltration rates. The results of this study showed that the prediction method provided adequate fits to field-measured data, and that the choice of an appropriate c factor is important in determining infiltration parameters from field data.