清浊变化是指常年及汛期的含沙量及输沙量变化。泾河年均径流量仅为渭河的1/2倍(资料截止1997),输沙量却为渭河的2.35倍,含沙量为渭河的4.57倍。现在是泾浊渭清。输沙量与最大流量间为正相关关系,相关系数渭河为0.7516,泾河为0.8279。输沙量季节集中的程度更大,最大月输沙量占年输沙量的71.23%,最大月径流量占年径流量的39.22%。渭河较小的输沙量在于气候干旱导致的径流量减小。泾河较大的输沙量在于泾河流域现代人为活动对生态系统破坏更为严重。

The water of a river changes from relatively clear to muddy presents the variations of it' s sediment concentration or suspended sediment discharge in a year or during flood season.According to hydrographic data, the average runoff volume of Jing River (from 1932 to 1997)is only half of that of Wei River (from 1950 to 1997), but the suspended sediment of Jing River is 2.35 times as much as that of Wei River. And It' s sediment concentration is about 4.57 times as much as Wei River' s. Now, the water of Jing River is more muddy than the water of Wei River. The analysis of runoff and sediment discharge shows that it is the positive interrelation between sediment and the peak discharge of the rivers' flow. The interrelation coefficients of above two indexes for Wei River and Jing River are 0. 7516 and 0. 8279 respectively. The sediment discharge is much more concentrative than the runoff in the season. The maximum monthly sediment discharge is 71.23 percent of yearly sediment discharge. And the maximum monthly runoff is only 39.22 percent of yearly runoff. In recent years, That the Wei River has a relative small amount of sediment is because of the decrease in runoff volume caused by climate drying in the basin.But the sediment discharge of Jing River increases because that ecological system in the basin has been seriously destroyed by human activities.