河道形态论文(结论修改).docVIP

Evolutionary investigatory of river channel morphology over last 20 years in Ningxia-Inner Mongolia Reaches of the Yellow River Abstract: Interpretation of river channel changes is not always straightforward since it requires a detailed reconstruction of the evolutionary trajectory and a quantitative analysis of channel morphology. Ningxia-Inner Mongolia Reaches of the Yellow River is analysed using data from more than 70 TM and ETM data of four periods (the year 1990, 2000, 2005 and 2010). The aim of this paper is to explain the river morphological evolution, river swing and curvature quantitative over the last 20 years in Ningxia-Inner Mongolia Reaches of the Yellow River. This study reveals that，The width of the main channel shows a decreasing trend and the entire channel swing to the right side, the river curvature from upstream to downstream shows a increasing trend. All of these changes in channel morphology were not conducive to flood-ice flows through the channel; Compare with entire Ningxia-Inner Mongolia Reaches the Bayangaole to Toudaoguai reaches has apparent channel shrinkage, swing, and a larger river curvature which the flood-ice disasters occurred frequently. The results presented herein will be useful when devising strategies for preventing flood-ice disaster formation in the Ningxia-Inner Mongolia reaches of the Yellow River. Keywords: Yellow River;Ningxia-Inner Mongolia Reaches; channel morphology; river swing; river curvature 关键词：黄河；宁蒙河段；河道形态；河道摆动；河道弯曲度 1 Introduction 黄河上游宁蒙河段，长约1237km，是发育典型的沙漠宽谷，是黄河上游近3500km长的河段中水沙变化最复杂、河道演变最剧烈的关键河段。近50多年来，由于气候变化、开发过度和生态破坏等因素导致黄河水沙关系加剧恶化，河槽萎缩，洪凌灾害频发，严重威胁宁蒙与下游河道的安全。大量研究表明河道形态在洪凌灾形成过程及行洪过程中都起着重要作用（）。利用多年发生洪凌灾的统计资料得知，洪凌灾害大多发生于河道弯曲度较大、宽度狭窄的河段。因此，有必要对黄河宁蒙河段河道形态及其演变过程进行分析，这对上游水库控泄流量控制及洪凌灾害预防都有重要意义。 River channel changes (i.e., decadal and centennial scales) have long attracted the attention of scientists(e.g., Gregory and Park, 1974; Petts,1979; Williams and Wolman, 1984; Kond