Examination of the seepage face boundary condition in subsurface and coupled surface/subsurface hydrological models
Examination of the seepage face boundary condition in subsurface and coupled surface/subsurface hydrological models
复制标题
地下和耦合地表/地下水文模型中渗流面边界条件的检查
DOI：
--
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
M. Putti
中科院分区：
文献类型：
--
作者：
C. Scudeler;C. Paniconi;D. Pasetto;M. Putti
渗流面是一个非线性的动态边界，它强烈地影响着压力水头分布、水位波动和流型。它在水文模型中的处理，特别是在非均质和地表/地下流耦合等复杂条件下的处理，还没有得到广泛的研究。在本文中，我们比较了静态(Dirichlet)和动态边界条件对渗流面的处理，在层状非均质条件下评估了它的分辨率，我们研究了它与集水出口边界的相互作用，并研究了地表/地下交换对陆地表面形成的渗流面的影响。这些分析是用一个综合的集水区水文模型进行的。对合成矩形坡度含水层和景观演变观测站的实验山坡进行了数值模拟。结果表明，对于动态渗流边界条件，静态边界条件并不总是适当的替代条件，特别是在高降雨、陡坡或非均质条件下；具有层状非均质性的山坡产生多个高度动态的渗流面；渗流面和出水口边界可以共存于一个完整的水文模型中，并且两者都起着重要的作用；地表的渗流面并不总是受地下水流控制。文中还提出了一种求解渗流面流的通用算法，该算法处理非均质性简单，适用于非结构网格，实验表明，该算法等同于地下水流模型中大气边界条件的处理。
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.