华北石质山区坡地产流模型

Plot-scale runoff generation model of lithoid mountainous areas in North China

坡地是流域的基本产流单元。对坡地产流模型的研究,可为研究流域的水文过程奠定基础。本文在认识坡地产流规律的基础上,经过对人工模拟降雨试验中取得的产流各个环节(降雨、出流及土壤含水量变化)的数据的分析,建立了一个具有物理机制的简单的坡面产流模型。其中,使用Horton模型模拟入渗和地表产流过程,用水箱模型模拟壤中流过程。模型能够同时对降雨过程中的地表、地下出流和土壤含水量变化过程进行模拟。计算得到的产流总量的误差较小,但在变化过程线上存在一些差异。这些差异主要是由模型对实际情况的简化和假定、数学模拟的局限性、变雨强降雨过程的复杂性等因素引起的。这种分层组合的坡面产流模型对华北石质山区的上层超渗、下层蓄满的产流特征是可行的。本文所做的工作是对华北石质山区分布式水文模型的产流模块的初步尝试。

The slopes are the basic Runoff Generation cells of the catchment. The study on the slope-scale runoff generation model can give references and proofs to the advanced research on the catchment-scale hydrological models. Thirteen Field Simulated Rainfall Experiments with different rainfall intensities and durations have been taken in a 5m × 10m experimental plot of Dongtaigou valley in the mountainous area in North China, and the process of rainfall, surface and subsurface flow and soil water moisture during the experiments have been automatically observed with intervals of 1min. Eased on the analysis of the observed data, we constructed a simple and physically based layered combinatorial model, which uses the Horton Infiltration Model for the infiltration and surface flow simulation, and uses the Tank Model for the subsurface flow, to simulate the runoff generation and soil moisture changing. The results simulated by the model have been compared with the measured rainfall-runoff course. The result shows that the layered combinatorial model is practicable in lithoid mountainous areas, where the runoff includes excess infiltration surface flow and excess storage subsurface flow. This model can simulate the surface and subsurface flow and soil moisture simultaneously, but the simulated routing curves some differences with the observed ones. These differences may be produced principally by （1） the predigestion and supposition in the model building phase, （2） the built-in limitation of the mathematical simulation, and （3） the complexity caused by the fluctuating rainfall intensity. It is an attempt on the Slope Runoff-generation Module of the distributed hydrological model in the lithoid mountainous areas in North China.