A Moisture Content-Discretized Infiltration Method

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XVI International Conference on Computational Methods in Water Resources (CMWR-XVI) Ingeniørhuset

A Moisture Content-Discretized Infiltration Method
Author:Cary Talbot <cary.a.talbot@erdc.usace.army.mil> (US Army ERDC)
Stacy Howington <stacy.e.howington@erdc.usace.army.mil> (US Army ERDC)
Fred Ogden <ogden@engr.uconn.edu> (University of Connecticut)
Presenter:Cary Talbot <cary.a.talbot@erdc.usace.army.mil> (US Army ERDC)
Date: 2006-06-18     Track: General Sessions     Session: General

In an effort to improve the computational efficiency and robustness of one-dimensional vadose zone flow calculations, alternatives to the Richards’ Equation (RE) are sought as part of on-going System-Wide Water Resources Program (SWWRP) research by the US Army Engineer Research & Development Center (ERDC) in the development of coupled surface and subsurface flow interaction codes. This paper will describe a depth- continuous, moisture content-discretized infiltration method under development at ERDC. The range of moisture content within a given soil is discretized into vertically continuous, interactive bins. The entry and vertical movement of wetting fronts in each bin are simulated by means of explicit infiltration approximations based on capillary and gravitational driving forces. Advancement of wetting fronts within a bin create pore- water deficits that are satisfied by capillary-driven inter-bin flow. The method inherently provides numerical stability and robustness because it precludes the need to include the explicitly non-linear constitutive models estimated by other vadose zone flow codes. Comparisons of method results with RE solutions and computational efficiency will be presented.