Incorporating spatially heterogeneous infiltration capacity into hydrologic models with applications for simulating post‐wildfire debris flow initiation
Incorporating spatially heterogeneous infiltration capacity into hydrologic models with applications for simulating post‐wildfire debris flow initiation
复制标题
将空间异质渗透能力纳入水文模型，用于模拟野火后泥石流的引发
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
B. Mirus
中科院分区：
文献类型：
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作者：
L. McGuire;F. Rengers;J. Kean;D. Staley;B. Mirus
野火后环境中的土壤通常具有较低的渗透能力，相对于未燃烧区域具有高度的空间异质性。泥石流通常是由最近烧毁的陡坡上的径流引起的，因此开发和测试将渗透能力的空间变异纳入水文模型的方法至关重要。我们使用Monte Carlo模拟在具有空间非均匀饱和导水率（Ks）的土壤上产生径流，推导出空中平均饱和导水率（Ke*）的表达式，该表达式取决于降雨率、Ks的统计特性以及与Ks相关的空间相关长度尺度。通过在广泛的空间尺度上模拟合成地形上的径流来测试确定Ke* 的拟议方法。结果提供了有效饱和导水率的简化表达式，可用于将小尺度Ks测量值的分布与较大空间尺度上的入渗和径流生成相关联。最后，我们使用基于Ke* 的水文模型来模拟美国加利福尼亚州圣安娜山脉最近被烧毁的集水区的径流和泥石流发生，并将结果与使用基于土壤保持服务曲线编号的渗透模型获得的结果进行比较。
Soils in post‐wildfire environments are often characterized by a low infiltration capacity with a high degree of spatial heterogeneity relative to unburned areas. Debris flows are frequently initiated by run‐off in recently burned steeplands, making it critical to develop and test methods for incorporating spatial variability in infiltration capacity into hydrologic models. We use Monte Carlo simulations of run‐off generation over a soil with a spatially heterogenous saturated hydraulic conductivity (Ks) to derive an expression for an aerially averaged saturated hydraulic conductivity ( Ke* ) that depends on the rainfall rate, the statistical properties of Ks, and the spatial correlation length scale associated with Ks. The proposed method for determining Ke* is tested by simulating run‐off on synthetic topography over a wide range of spatial scales. Results provide a simplified expression for an effective saturated hydraulic conductivity that can be used to relate a distribution of small‐scale Ks measurements to infiltration and run‐off generation over larger spatial scales. Finally, we use a hydrologic model based on Ke* to simulate run‐off and debris flow initiation at a recently burned catchment in the Santa Ana Mountains, CA, USA, and compare results to those obtained using an infiltration model based on the Soil Conservation Service Curve Number.