美国基西米河渠化工程对河流生态环境的影响

位于美国佛罗里达州的基西米河，所处流域自然条件优越，季节性的水流变化较大，河流沿岸湿地资源丰富，为各种水生生物提供了适宜的生存环境，构成了流域内丰富多彩的生态系统．由于防洪排涝的需要，1961年开展了大规模的渠化工程，将蜿蜒的自然河流变成了几段较为顺直的人工运河，提高了河道的防洪能力，然而渠化后的河道及其下游流域的生态环境也随之出现了一系列负面反应，原有的生态平衡受到破坏，教训是非常深刻的．文中针对该渠化工程的后果及教训进行了总结和介绍。

Impact of channelization on the ecological environment in Kissimmee River,USA

Before being channelized, the Kissimmee River had supported a large-scale wetland habitat and thus maintained a flourishing and complex ecosystem in its basin, which were benefited from the geographical conditions and the flow's changing with natural seasonal characteristics. After its channelization in 1961, the originally meandering river was changed into a man-made canal consisting of several nearly straight reaches. Channelization increased the discharging capacity of the river, and therefore raised the flood control standard of the river. At the same time, it brought negative impacts on the ecosystem of the river basin and the natural ecological balance was destroyed. The paper is a summary of the ecological impacts of the channelization and the lessons learned.