中文摘要：

河流曲度是河流平面形态的重要表征指标,以平原河网地区典型区域——上海为例,分析了20世纪50年代中心城区高密度河网的河流曲度特征,诊断了近60年以来快速城市化对区域河网及河流曲度的影响。研究认为：①近60年来上海中心城区河网密度下降幅度达67.22%,高强度人类活动导致区域河网水系分枝结构与自然规律完全相反;②平原河网地区是顺直型河流的典型发育区域,研究初期上海中心城区顺直型河流占85.40%,进一步分析表明曲度小于1.1的河流比例高达70.57%,河流形态接近于直线型;③上海中心城区消亡河流以顺直型为主,其消亡速率约为较高曲度河流的12倍,采用加权平均曲度指标描述区域河网萎缩对河流曲度的影响具有更好的直观性和科学性;④上海城市河流综合整治实践中,工程水利的倾向性强于生态水利,60.9%的河流整治项目开展了裁弯取直工程措施。

英文摘要：

River sinuosity is an important indicator of channel planform.The city of Shanghai is a typical tidal plain and chosen as the study area in this paper.Sinuosity values in the 1950 were studied for the city centre region with dense river networks.The impacts of rapid urbanization on river sinuosity are diagnosed for the period after 1960.The result shows that the density of river networks in the city centre region has been reduced by 67.22% due to intense human activities since 1950,which resulted in Horton laws of drainage composition no longer holds.The tidal plain is seen as a representation of developing regions on straight rivers.The latter can account for 85.4% of the total number of rivers in the city centre region in the 1950.A further analysis of sinuosity reveals that those straight rivers with sinuosity values less than 1.1 can be as high as 70.57% at the time.The number of destroyed straight rivers in the city centre region was 12 times more than those with higher sinuosity in the past 60 years.We thus propose the adaptation of the index of weighted average river sinuosity for the study of the influence of river network shrinking on river sinuosity.Finally,it is found that in the practice of the comprehensive treatment of Shanghai river system,the tendency is to use engineering-oriented measures rather than replying to natural meandering channels as the curving cut-off measure has been applied to 60.9% river projects.