蔡家川流域降雨-径流关系及水量平衡分析

Analyses of Rainfall-Runoff Relationship and Water Balance in Caijiachuan Watershed

以晋西黄土区蔡家川流域为研究对象,利用该流域2004—2009年的降雨径流实测数据,采用多重比较和回归分析等统计方法,对降雨—径流关系及水量平衡进行了研究。结果表明,流域年耗水量占年降雨量的比例高达90%以上,是水循环过程中的重要支出项;流域年径流系数只有1.60%～2.66%;场降雨条件下径流量和洪峰流量随雨量P和最大60min雨强I60的量级具有明显的跳跃式变化,当P≥30mm时,径流量、洪峰流量分别是0～10mm雨量级的8.31,6.52倍,当I60≥20mm/h时,径流量、洪峰流量分别是0～10mm/h雨强级的3.35,16.87倍;对不同雨型下径流量、洪峰流量与降雨指标进行多元回归分析后得出,短历时高雨强的A型雨下雨强对洪峰流量的贡献率(47.12%)大于历时较长且雨强较大的B型雨(44.62%)和长历时低雨强的C型雨(32.51%),C型雨下雨量对径流量的贡献率(28.5%)大于A型雨(26.69%)和B型雨(3.15%)。

By taking Caijiachuan watershed on the Loess Plateau of Western Shanxi Province,as the study object,the relationship between rainfall and runoff and the water balance in the experimental watershed were studied using statistical methods such as multiple comparison and regression analysis for the data of precipitation and runoff measured in the watershed from 2004 to 2009.Results showed that the percentage of yearly water consumption was 90% more than yearly rainfall.Water consumption appeared to be the main water output in the water cycle of the experimental watershed.The yearly runoff coefficient ranged only from 1.6% to 2.66%.Runoff and peak discharge for a single rainfall event changed evidently with changes in the magnitude order of rainfall amount（P） and the maximum 60-min rainfall intensity（I60） in a jump mode.Specifically,runoff volume and peak discharge for P≥30 mm rainfall were about 8.31 and 6.52 times of those for the 0~10 mm order of rainfall amount,respectively.Runoff volume and peak discharge for I60≥20 mm/h rainfall intensity were about 3.35 and 16.87 times of those for the 0~10 mm/h order of rainfall intensity,respectively.Regression analysis of runoff,peak discharge,and rainfall indexes under different types of rainfall showed that the contribution of rainfall intensity to peak discharge was highest（47.12%） under A-type rainfall（stom events with short duration and high intensity） as compared to that under B-type rainfall（storm events with long duration and high intensity,44.62%） and C-type rainfall（storm events with long duration and low intensity,32.51%）,while the contribution of rainfall amount to runoff was highest（28.5%） under C-type rainfall as compared to that under A-type rainfall（26.69%） and B-type rainfall（3.15%）.