现在，泥沙淤积抬高了中游河床，使得以前得到保护的低地现在暴露在每年洪季漫溢的威胁之下。

The sedimentation has now elevated the river bed in the middle reach to such an extent that the formerly protected lowlands are now exposed to the threat of overflow every flood season.

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我国许多河流通航不仅受到洪、枯季水位变化的影响，还受到其它因素的影响，尤其是河道上修建水电站。

Many navigable channels in our country are affected not only the mutation of water level of flood and dry weather, but also other factors. For example, the hydroelectric power station in upstream.

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