近期长江与鄱阳湖汇流河段冲淤变化与微地貌特征

Fluvial processes and micro-topography characteristics in the Yangtze River and Poyang Lake confluence in recent years

2016年9月利用多波束测深系统对长江与鄱阳湖汇流河段进行高分辨率观测,结合1998年及2013年水下地形资料,探讨近期该河段河槽冲淤变化与微地貌特征。结果表明：1998-2013年研究河段整体呈冲刷特征,净冲刷634.92万m^3。其中,汇流上段主要为深槽冲刷,最大冲刷深度可达8.7 m;而汇流中段河槽呈整体冲刷,汇流下段河槽呈轻微淤积。在航道整治工程的约束下,汇流河段河势相对稳定,且航道为主要冲刷区。长江与鄱阳湖汇流河段主要发育了沙波、平床及冲刷痕等微地貌。流域来沙量减少导致床面泥沙粗化,为研究河段沙波的广泛发育提供了物质基础。

Fluvial processes and micro-topography characteristics in the confluence area of the Yangtze River and Poyang Lake were studied by data of multi-beam echo sounding,sediment samples in September 2016 and bathymetric data in 1998 and 2013. Results show that： the study area scoured obviously and the net scour amount reached 634. 92 × 10~4 m^3 from 1998 to 2013. Upper reaches of confluence undergoing excess erosion of 8. 7 m in deep trough; the whole trough of middle reaches was scoured and slight accumulation in the lower reach of the confluence. Due to the waterway regulation project from 2001 to 2009,the confluence reaches are stable,and the navigation channel was the mainly scour area. Dunes,smooth bed floor and scour were developed in the confluence river. The decrease of sediment discharge induced sediment coarsening,which provides the material for the development of dunes.