1970—2015年秦岭北麓径流重建及变化

渭河流域能否高质量发展的一个关键就是水资源的问题,而秦岭北麓是渭河的重要产水区。为探究秦岭北麓近年水资源的变化特征,采用VIC(Variable Infiltration Capacity)模型,基于水文相似性原理,运用典型流域参证法,重建了1970—2015年秦岭北麓径流变化。结果表明:VIC模型在观测流域有着较高的适用性,在月径流模拟中,纳什系数(N_S)大于0.76,相关系数(R²)大于0.91,相对误差(RE)小于±15%; 通过水文参数移植法模型可以真实还原无观测流域径流变化,在验证期N_S,R²,RE分别为0.81,0.94,4.6。近46 a来北麓径流总量在(16.01～65.4)亿m³/a波动,1983年径流量最高达到65.4亿m³,而1977年最小值仅为16亿m³,丰水年份是枯水年份的4倍,径流年际变化明显,过去46 a秦岭北麓多年平均径流值为35.2亿m³/a。降水是径流变化的主导因素,并且也是水文模拟中最重要的影响要素。

Change and Retrieval of Runoff in the Northern Foothills of Qinling Mountains from 1970 to 2015

The key point whether Weihe River Basin can develop in a high quality depends on the water resources.However,the northern foothills of Qinling Mountains is the important area of water production in Weihe River Basin.In order to explore the change characteristics of the water resources in the northern foothills of Qinling Mountains in recent years,we adopted VIC(Variable Infiltration Capacity)model which based on the principle of hydrological similarity and applied typical watershed reference method to retrieve the changes of runoff in the northern foothills of Qinling Mountains.The results show that VIC model has a high applicability in the observed watershed;in monthly runoff simulation,Nash coefficient(N_S)is greater than 0.76,correlation coefficient(R²)is greater than 0.91,and relative error(RE)is less than±15%;the hydrological parameter transplantation model can be used to restore the runoff change in unobserved watershed;in the validation period,N_S,R² and RE were 0.81,0.94 and 4.6,respectively;the runoff volume of the northern foothills had fluctuated between 1.601 billion m³ and 6.54 billion m³ per year in the past 46 years;the maximum runoff reached 6.54 billion m³ in 1983 and the minimum runoff was only 1.6 billion m³ per year in 1977;the runoff in high flow year was four times higher than that in low flow year,which showed the obvious interannual variation of runoff;the average annual runoff in the northern foothills of Qinling Mountains was 3.52 billion m³ per year in many years over the last 46 years.Precipitation is the leading factor of runoff variation and the most important influencing factor in hydrological simulation.