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Modeling the effects of a time‐dependent wetted perimeter on infiltration from ephemeral channels
Author(s) -
Freyberg David L.
Publication year - 1983
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr019i002p00559
Subject(s) - infiltration (hvac) , ephemeral key , soil science , water content , hydrograph , geology , geotechnical engineering , hydrology (agriculture) , geometry , mechanics , environmental science , mathematics , surface runoff , physics , meteorology , algorithm , ecology , biology
The effects of a time‐dependent wetted perimeter on infiltration from ephemeral stream channel cross sections are explored using a conceptually simple mathematical model. The model is based on the assumptions of vertical soil moisture flow and the validity of the Green‐Ampt model for vertical infiltration. By using a simple channel geometry, an analytic solution is found for the case in which the gravitational component of soil moisture flow may be neglected. An efficient, accurate numerical technique provides approximate solutions in the general case. Application of the model demonstrates that cross‐sectional infiltration, that is, infiltration per unit length of channel, is a complex function of soil properties, channel geometry, and hydrograph shape. For the channel geometry considered, the direct effects of variable water pressure at the ground surface are overshadowed by the effects of variation in the wetted perimeter, with the result that the temporal variation in infiltration rate is quite unlike that which would be predicted assuming ponded infiltration alone.