A multiple wetting front gravitational infiltration and redistribution model for water balance applications

Abstract

[1] A unit gradient multiple wetting front model is described, in which the infiltration and redistribution behavior of individual ''square wave'' fronts is simulated for unponded rainfall infiltration. Drainage recession behavior of this model is demonstrated to be equivalent to that of a capacitance (bucket) model for certain scenarios, suggesting a possible physical basis for capacitance model parameters with respect to drainage prediction. The ability of the wetting front model to account for the variable time lag between surface infiltration and drainage generation at depth, which cannot be achieved using a capacitance model, is demonstrated to improve predictions of the 25-year average drainage regime of a free-draining lysimeter in Colbitz, Germany, when compared to capacitance model predictions. Improvement in predictions compared to the capacitance model is most apparent in deeper and drier soils, where the infiltration-drainage time lag is significant. Comparison with a numerical Richards equation solution suggests that drainage behavior predicted by the model is reasonable for the conditions considered, despite neglecting capillary impacts. The ability of the model to differentiate between drainage response time and the age of draining water gives the approach general applicability for problems requiring simulation of the age of water involved in hydrological response to storms.

Towards reconstruction of the flow duration curve: development of a conceptual framework with a physical basis

“…Instead, the shape of the SSFDC reflects the competition between seasonal variability of precipitation and potential evapotranspiration in the vadose zone, which governs recharge to the water table, and then the filtering of the groundwater recharge flux by the dynamic aquifer through subsurface drainage. Previous work has explored the process controls on the recharge (Struthers et al, 2006;McGrath et al, 2007;Harman et al, 2011), and on shallow subsurface flow in hillslopes (Harman and Sivapalan, 2009).…”

Improving model structure and reducing parameter uncertainty in conceptual water balance models through the use of auxiliary data

“…We provide the basic equations of the multiple wetting front model below, but more details are given by Struthers et al [2006].…”

“…[24] In order to capture this process more realistically but within a simple model structure, model 3 was developed through the incorporation of the ''multiple wetting front'' model [Struthers et al, 2006]. All other aspects of the model are similar to model 2.…”

“…The differences between the three models are then only in respect of the internal process descriptions and the inclusion or otherwise of a saturated groundwater store to simulate deep groundwater flows. In the case of model 3, the unsaturated zone dynamics is captured through the use of a multiple wetting front model of Struthers et al [2006], which is implemented for every one of the 10 buckets that represent the downstream variation of soil depth. The details of the three models, including the governing equations are presented in Appendix A.…”

Pseudo-hysteretic double-front hiatus-stage soil water parcels supplying a plant–root continuum: the Green-Ampt-Youngs model revisited

“…al. 1997, Selker et al 1999, Leconte and Bissette 2001, Mishraet al 2003, Serrano 2004, Chua and Marino 2005, Warrick et al 2005, Zeleke and Si 2005, Chen and Young 2006, Struthers et al 2006, Loáiciga and Huang 2007, Melone et al 2008, Clemmens and Bautista 2009, Gowdish and Munoz-Carpena 2009, Wang and Horton 2009, Kacimov et al 2010a, 2010b, Ma et al 2010, Liu et al 2011, Singh 2011, Voller 2011, although anti-GA arguments (e.g. Dixon 1976) are also sound.…”