【摘要】 糙率系数是地面灌溉设计和管理的基本参数之一。为了更好地进行地面灌溉系统的设计和管理,研究了畦灌糙率系数的变异规律,并分析了其对灌水效果的影响。在110m的畦田长度上,观测了水流推进过程及沿程各点的水深,采用曼宁公式的数值解法估算了26条畦田的田面糙率系数,分析了其变异规律,评价了糙率系数对灌水质量评价指标的影响。结果表明,裸地畦田的平均糙率系数在0.038左右,其变异程度为中等强度。对试验区域内各畦田灌水模拟结果显示,当采用平均糙率系数模拟灌水效果评价指标时,与采用各畦田实际糙率系数相比,灌水效率指标最大相对误差达6.48%,灌水均匀度最大相差66.67%。因此,在实际地面灌溉设计与管理中,糙率系数的这种差异性不可忽略。更多还原

【Abstract】 Roughness coefficient is one of the basic technical parameters in the design and management of surface irrigation system. The spatial variability and poor estimates of roughness coefficient can affect the evaluation and management of surface irrigation system. In this paper, the variability of roughness coefficient and its effect on border irrigation performance were studied. The water advance and water depth along the 110 m border strips were observed, then the roughness coefficient was calculated by numerical solution of Manning formula, the variability of roughness coefficient and its effect on border irrigation performance were analyzed. The results indicated that the average roughness coefficient of bare land was 0.038, its variation degree was moderate. The simulation results for 26 border strips indicated that the biggest relative error of application efficiency and distribution uniformity were 6.48% and 66.67% separately, in which the average and actual roughness coefficient were adopted. Therefore the variability of roughness coefficient was not ignored in the actual design and management of surface irrigation.更多还原