ANALYSIS ON PRESENT CHARACTERISTICS OF DIFFERENCE BETWEEN JING RIVER AND WEI RIVER IN RUNOFF AND SEDIMENT

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.