Mountain block systems are critical to water resources and have been heavily studied and modeled in recent decades. However, due to lack of field data, there is little consistency in how models represent the mountain block subsurface. While there is a large body of research on subsurface heterogeneity, few studies have evaluated the effect that common conceptual choices modelers make in mountainous systems have on simulated hydrology. Here we simulate the hydrology of a semi‐idealized headwater catchment using six common conceptual models of the mountain block subsurface. These scenarios include multiple representations of hydraulic conductivity decaying with depth, changes in soil depth with topography, and anisotropy. We evaluate flow paths, discharge, and water tables to quantify the impact of subsurface conceptualization on hydrologic behavior in three dimensions. Our results show that adding higher conductivity layers in the shallow subsurface concentrates flow paths near the surface and increases average saturated flow path velocities. Increasing heterogeneity by adding additional layers or introducing anisotropy increases the variance in the relationship between the age and length of saturated flow paths. Discharge behavior is most sensitive to heterogeneity in the shallow subsurface layers. Water tables are less sensitive to layering than they are to the overall conductivity in the domain. Anisotropy restricts flow path depths and controls discharge from storage but has little effect on governing runoff. Differences in the response of discharge, water table depth, and residence time distribution to subsurface representation highlight the need to consider model applications when determining the level of complexity that is needed.

中文翻译：

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模拟山地水文对地下概念化的敏感性

山区系统对水资源至关重要，近几十年来已进行了大量研究和建模。但是，由于缺乏现场数据，模型在表示山地块地下的方式上几乎没有一致性。尽管有大量关于地下非均质性的研究，但很少有研究评估建模人员在山区系统中做出的常见概念选择对模拟水文学的影响。在这里，我们使用六个常见的山地块地下概念模型来模拟半理想化的源头流域的水文学。这些方案包括水力传导率随深度衰减，土壤深度随地形变化以及各向异性的多种表示形式。我们评估流路，排放，和地下水位，从三个方面量化地下概念化对水文行为的影响。我们的结果表明，在较浅的次表面中添加较高的电导率层会使表面附近的流路集中，并增加平均饱和流路速度。通过添加额外的层或引入各向异性来增加异质性，会增加饱和流路的寿命和长度之间关系的变化。放电行为对浅层地下的非均质性最敏感。地下水位对分层的敏感性低于对区域内总体电导率的敏感性。各向异性限制了流径的深度并控制了储存的流量，但对控制径流量影响很小。排水反应，地下水位深度，