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根据渭河源区清源河典型小流域实测水文资料,分析了流域水文要素的年内和年际变化规律,流域降水、径流和泥沙主要集中在汛期,5-9月降水量占全年的78.5%,5-10月径流占全年的78.7%,5-8月输沙量占全年的88.9%。受上游修建水库、水土保持等人类活动的影响,流域汛期径流和泥沙1997-2013年比1980-1996年均减少了5.9%。流域面平均降水量、平均流量、平均输沙量年际变化不稳定,总体呈减少趋势,序列最大可能变异点分别为1995年、1994年和1997年。建立了流域年降水量与年径流深、次降水量P+Pa与次径流深相关模型,相关系数达到0.902和0.860。以年最大洪峰流量为参数,分别建立了流域年径流量与年输沙量、次径流量与次输沙量关系模型,相关系数达到0.835和0.917,公式模拟值与实测值接近,误差较小,可以作为以径流推算泥沙的重要依据。通过定性定量分析人类活动对流域径流、泥沙的影响程度,对区域抗旱防洪减灾、水资源管理、小流域治理及生态环境保护具有重要意义。
Based on the observed hydrological data of typical small watersheds of Qingyuan River in the Weihe River, the annual and interannual variation of hydrological elements in the watershed are analyzed. Precipitation, runoff and sediment are mainly concentrated in the flood season. The precipitation in May-September accounts for 78.5% The runoff from May to October accounted for 78.7% of the whole year, and the sediment discharge from May to August accounted for 88.9% of the whole year. Affected by the human activities of reservoirs and water and soil conservation in the upper reaches, the runoff and sediment in flood season in the river basin decreased by 5.9% from 1997 to 2013 respectively as compared with 1980-1996. The interannual variability of average precipitation, average flow and average sediment load in the watershed is not stable, with an overall decreasing trend. The maximum possible variation of the sequence is 1995, 1994 and 1997 respectively. The correlation model between annual precipitation and annual runoff depth, secondary precipitation P + Pa and secondary runoff depth was established. The correlation coefficient reached 0.902 and 0.860. Based on the annual maximum flood discharge, the annual runoff, annual sediment discharge, secondary runoff and secondary sediment load were established respectively. The correlation coefficients reached 0.835 and 0.917 respectively. The simulated and measured values were close to each other with small error , Can be used as an important basis for sediment calculation by runoff. The qualitative and quantitative analysis of the impact of human activities on runoff and sediment in the watershed is of great significance to regional drought relief, water resources management, small watershed management and ecological environment protection.