Laboratory and numerical investigations of hillslope soil saturation development and runoff generation over rainfall events

Phi, Son, Clarke, William and Li, Ling (2013) Laboratory and numerical investigations of hillslope soil saturation development and runoff generation over rainfall events. Journal of Hydrology, 493 1-15. doi:10.1016/j.jhydrol.2013.04.009


Author Phi, Son
Clarke, William
Li, Ling
Title Laboratory and numerical investigations of hillslope soil saturation development and runoff generation over rainfall events
Journal name Journal of Hydrology   Check publisher's open access policy
ISSN 0022-1694
Publication date 2013-06
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.jhydrol.2013.04.009
Volume 493
Start page 1
End page 15
Total pages 15
Place of publication Amsterdam, The Netherlands
Publisher Elsevier
Collection year 2014
Language eng
Formatted abstract
Runoff is a key process that controls the behaviour of a hillslope hydrological system. The study presented here aims to examine the mechanisms of runoff generation due to saturation excess by investigating the development of the subsurface saturated zone. Experiments were conducted on a hillslope system with a uniform slope (0.2) and a relatively homogeneous and highly permeable medium (Ks=. 1.28. cm/min), subjected to high and constant surface recharges (0.51-0.69. cm/min). Two initial conditions prior to the rainfall events were set up in the experiments to represent relatively dry and wet antecedent soil conditions, respectively. Measurements showed that during vertical infiltration, local pressure head and soil moisture remained constant for a certain period, showing a 'waiting' behaviour. The saturated area formed initially at the slope toe, quickly rose to the surface and subsequently expanded to the upslope. When propagating in the upslope direction, the wetting front caused the pore-water flow to deflect in areas above the wetting front and at the slope base. With a wetter initial condition, the soil responded to the rainfall more quickly. The initial moisture conditions also altered the relation between the subsurface discharge and pressure head. Under the applied rainfall rates, the system reached a fully saturated condition and produced surface runoff. The rainfall intensity was found to affect the temporal variations and magnitude of surface runoff characteristics; however it did not seem to impose any significant effect on the maximum subsurface discharge rate. These results provide insight into the behaviour of the hillslope system in response to rainfall.
Keyword Wetting front
Saturated zone
Surface and subsurface flow coupling
Soil pressure head response
Modhms
Storage Boussinesq Model
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
Official 2014 Collection
 
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