基于畦灌水流推进过程推求田面平均糙率的简化解析模型

基于水量平衡模型，通过引入畦灌下渗水形状系数、地表储水形状系数，并分析了两系数的变化规律，发现下渗水形状系数受地表水推进过程中的推进距离和时间的幂指数影响很小，可用一个稳定值计算，由此建立了基于水量平衡法的畦灌时反推田面糙率简化模型．结合大田试验和相关资料对模型进行检验，表明该模型具有严谨的物理基础，计算求解方便，精度较高的优点，可用于畦灌时田面糙率的确定．

On Simplified Analytic Model of Ascertaining Manning Roughness Based on Border Irrigation Water Movement

Based on water balance model, this paper analyzes the relationship between figure coefficient of infiltration water and figure coefficient of surface storage under the condition of border irrigation. It is found that the power index of movement distance and time have little effect on the figure coefficient of infiltration water in the course of surface water movement, which can be substituted by a stable value. A simplified analytic model to back ascertain Manning Roughness of border irrigation on the basis of water balance method is set up and testified in field experiment and some previous results. It is shown that the model has some advantages, such as a strict physical foundation, simple calculation and solution, higher accuracy. Thus it can be used to decide the Manning Roughness of border irrigation.