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Examination of the seepage face boundary condition in subsurface and coupled surface/subsurface hydrological models.
- Source :
- Water Resources Research; Mar2017, Vol. 53 Issue 3, p1799-1819, 21p
- Publication Year :
- 2017
-
Abstract
- 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. [ABSTRACT FROM AUTHOR]
- Subjects :
- BOUNDARY value problems
HYDROLOGY
MATHEMATICAL models
Subjects
Details
- Language :
- English
- ISSN :
- 00431397
- Volume :
- 53
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Water Resources Research
- Publication Type :
- Academic Journal
- Accession number :
- 122710957
- Full Text :
- https://doi.org/10.1002/2016WR019277