5•12汶川地震，不仅直接影响灾区河流的河道，并诱发了大量崩塌、滑坡、泥石流、堰塞湖等次生山地灾害，这些山地灾害的产生和发展将对震区河流的演化产生深远影响。因此，对震后山区河流河道演化规律和发展趋势进行准确的分析和预测，是震区河道修复及震后恢复重建的关键。结合野外考察资料，分别从河型、纵断面、横断面3方面分析了震区河流的演化特点。分析结果表明：河床剧烈抬升引起河型游荡分汊，两岸频发的山地灾害挤压河道；高强度山洪冲刷河床及岸滩并展宽河道，泥沙的淤积也可束窄河道；河流纵断面总体淤高，但纵断面结构渐趋稳定，大石块多且上游来水来沙丰富的河段会逐渐发育成阶梯状结构，而以淤积为主的河段，由于山洪冲刷会形成下凹型纵断面，并逐渐向直线型纵断面发展。

Apart from the direct effect on the river channel, secondary mountain  disasters induced by Wenchuan big earthquake in 2008 including collapses, landslides, debris flows and barrier lakes have far-reaching influences on river channel morphology in the earthquake region. Based on field data, we analyzed the characteristics of river channel evolution and predicted its development to assist the recovery and reconstruction after the earthquake. In terms of the river pattern, wandering and braided rivers were formed because of severe riverbed uplift, and the channel changed its route owing to extrusion by loose materials from mountain hazards on both sides. Regarding the cross section, high-intensity flood scoured the riverbed and then broadened the river channel; whereas sediment deposition could also narrow the channel. The vertical profile of the river was elevated in general with its structure becoming more stable. River reaches with large rocks and abundant incoming water and sediment will gradually develop to ladder-like structure; while reaches subject to deposition in mid-stream and downstream of the mountain area will exhibit concave profile due to scouring and will develop to linear profile.