Examination of the seepage face boundary condition in subsurface and coupled surface/subsurface hydrological models.

Scudeler, Carlotta; Paniconi, Claudio; Pasetto, Damiano et Putti, Mario (2017). Examination of the seepage face boundary condition in subsurface and coupled surface/subsurface hydrological models. Water Resources Research , vol. 53 , nº 3. pp. 1799-1819. DOI: 10.1002/2016WR019277.

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Résumé

A seepage face is a nonlinear dynamic boundary that strongly affects pressure head distributions, water table fluctuations, and flow patterns. Its handling in hydrological models, especially under complex conditions such as heterogeneity and coupled surface/subsurface flow, has not been extensively studied. In this paper, we compare the treatment of the seepage face as a static (Dirichlet) versus dynamic boundary condition, we assess its resolution under conditions of layered heterogeneity, we examine its interaction with a catchment outlet boundary, and we investigate the effects of surface/subsurface exchanges on seepage faces forming at the land surface. The analyses are carried out with an integrated catchment hydrological model. Numerical simulations are performed for a synthetic rectangular sloping aquifer and for an experimental hillslope from the Landscape Evolution Observatory. The results show that the static boundary condition is not always an adequate stand-in for a dynamic seepage face boundary condition, especially under conditions of high rainfall, steep slope, or heterogeneity; that hillslopes with layered heterogeneity give rise to multiple seepage faces that can be highly dynamic; that seepage face and outlet boundaries can coexist in an integrated hydrological model and both play an important role; and that seepage faces at the land surface are not always controlled by subsurface flow. The paper also presents a generalized algorithm for resolving seepage face outflow that handles heterogeneity in a simple way, is applicable to unstructured grids, and is shown experimentally to be equivalent to the treatment of atmospheric boundary conditions in subsurface flow models.

Type de document:	Article
Mots-clés libres:	aquifères; mouvements atmosphériques; bassins versants; modèle climatique; eaux souterraines; hydrologie; ruissellement; infiltration;
Centre:	Centre Eau Terre Environnement
Date de dépôt:	16 juin 2017 15:54
Dernière modification:	24 juill. 2017 09:10
URI:	https://espace.inrs.ca/id/eprint/5147

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