长江下游马鞍山河段演变趋势分析

Fluvial processes trend of Ma'anshan reach in Lower Yangtze River

基于历年实测资料,详细分析了马鞍山河段演变规律及其对上游陈家洲汊道段演变的响应机理,进而揭示了马鞍山河段演变趋势。结果表明,马鞍山河段多年来保持分汊河势格局,右汊河势相对稳定,但左汊河势变化剧烈,左汊深泓平面位置与上游陈家洲汊道河势演变密切相关,当陈家洲左汊发展、西梁山挑流作用较强时,江心洲左汊深泓呈二次过渡,当陈家洲右汊发展、西梁山挑流作用较弱时,江心洲左汊深泓呈一次过渡。近期,陈家洲左汊淤积、右汊冲刷,陈家洲头低滩切割趋势明显,这些变化将会导致西梁山挑流作用逐渐减弱,马鞍山河段左汊主流可能逐渐调整成一次过渡形式,左汊内河势将发生较大调整。

Based on historic observed data,fluvial processes of Ma＇anshan reach with response to variation of Chenjiazhou reach were analyzed in detail. Then the evolution trend of Ma＇ anshan reach was discussed. The results indicate that Ma＇anshan reach keeps braided for many years,and the right branch is relatively stable,but the left branch changes seriously. The plane position of thalweg in left branch of Ma＇ anshan reach was closely related to the evolution of Chenjiazhou reach. When the left branch in Chenjiazhou reach is scoured and the Xiliangshan has a strong trajectory flow effect,the thalweg in the left branch of Ma＇anshan reach has twice transitions. While the left branch in Chenjiazhou reach is silted and the Xiliangshan has a weak trajectory flow effect,the thalweg in the left branch of Ma＇ anshan reach has only once transition. Recently,the left branch is deposited,but the right branch is eroded,and the low breach in front of Chenjiazhou is scoured obviously. All these evolutions will weaken trajectory flow effect of Xiliangshan. The thalweg in the left branch of Ma＇anshan reach will changed from two to only one time transition,and the river regime in the left branch of Ma＇anshan reach will adjust significantly.