Numerical calculation of secondary discharge peak from a small watershed using a physically based watershed scale infiltration simulation
Numerical calculation of secondary discharge peak from a small watershed using a physically based watershed scale infiltration simulation
复制标题
使用基于物理的流域规模渗透模拟对小流域二次流量峰值进行数值计算
DOI：
10.1007/s10310-007-0008-x
复制
发表时间：
2007
影响因子：
1.5
通讯作者：
K. Haibara
中科院分区：
文献类型：
--
作者：
K. Shiraki;Yoshiki Shinomiya;R. Urakawa;H. Toda;K. Haibara
采用基于理查兹方程的简化物理三维饱和和非饱和水流模型，进行了数值渗透模拟，以重现山地森林流域（流域面积1.89公顷，平均表土深度2.61米，基岩地质，中生代-古生代）的二次流量峰值。我们能够计算出在降雨期间的快速排放和二次排放高峰的分水岭同时，使用观测到的地形信息，表土深度分布，和土壤水力特性，并通过将分水岭分为2.5米水平和10个细胞垂直。虽然计算的过程线不完全同意与观测过程线，我们得出结论，观测过程线的特点更好的精度解释使用较小的土壤孔隙度模式比使用观测模式。验证了基于理查兹方程的模拟方法在分析流域径流过程中的有效性。计算比较澄清，较低的土壤孔隙度加快二次放电峰值的时间，并增加其体积。附加的检查，如土壤水力特性的分布和Hortonian坡面流的实际条件，是必要的，以精确地模拟在预定的流域的径流过程。
Numerical infiltration simulations were performed to reproduce secondary discharge peaks in a mountainous forest watershed (watershed area, 1.89 ha; average topsoil depth, 2.61 m; and bedrock geology, Mesozoic–Paleozoic) using a simplified physically based three-dimensional saturated and unsaturated water-flow model based on Richards’ equation. We were able to calculate the quick discharge during rain and a secondary discharge peak at the watershed simultaneously, using observed topographical information, the topsoil depth distribution, and soil hydraulic characteristics, and by dividing the watershed by 2.5 m horizontally and ten cells vertically. Although the calculated hydrograph did not agree entirely with the observed hydrograph, we conclude that the characteristics of the observed hydrograph were explained with better accuracy using the smaller soil porosity patterns than using the observed patterns. We verified that the simulation method based on Richards’ equation was effective to analyze the rainfall-runoff processes toward the intended watershed. Computational comparisons clarified that lower soil porosity quickens the timing of secondary discharge peaks and increases their volume. Additional examinations, such as the distribution of soil hydraulic characteristics and the actual condition of Hortonian overland flow, are necessary to simulate rainfall-runoff processes precisely at the intended watershed.