渭河水沙变化及特性分析

Sediment and Water Change in the Wei River and the Characteristics Analysis

由于受地形和大气环流的影响以及下垫面的不同，渭河流域水沙异源，西北多沙，东南多水。７０年代以来，渭河水沙发生了较大变化，水沙量不断减少，但水量减少幅度大于沙量，而且较小流量级输沙百分比增加。１９８６～１９９６年，渭河发生大洪水较少，洪水量也较小，但高含沙洪水仍然存在，而且含沙量增加，输沙量也很大，特别是以泾河来水为主时，常出现高含沙水流。

Owing to the impacts from various landforms, atmospheric circulation and land surface, water and sediment into the Wei River are come from different regions with more sediment from northwestern part and more runoff from southeastern part. Sediment and water in the Wei River have changed significantly since 1970s, that is, continuous decrease of water and sediment but with more reduction of water than that of sediment and increase of coefficient of sediment transfer under small discharges. There were less large floods and with less flood volume in the Wei River from 1986 to 1996, but there still occurred hyper concentrated flood with increased sediment concentration and great sediment transport, especially often occurred hyper concentrated floods in cases of water mainly came from the Jing River.