1.The Columbia River, fourth-largest by volume in North America (annual average of 192 million acre-feet at the mouth), beginsat Columbia Lake in the Rocky Mountain Trench of southeastern British Columbia at about 2656 feet above sea level.

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2.The river then bendswest, south and east through central Washington, turns south and then west, and forms the border between Oregon and Washington to the Pacific ocean.

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3.Because of its unique situation close to the ocean and laced with tall mountain ranges, the Columbia evolved as one of the great rivers of the world in terms of its runoff and the diversity of its habitat.

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4.The combination of high volume with stable canyons walls makes the Columbia an ideal hydropower river.

黄河，中国北部大河，全长约5464公里，流域面积约752443平方公里。世界长河之一，中国第二长河。

黄河发源于青海省青藏高原。呈“几”字形，自西向东分别流经青海、四川、甘肃、宁夏、内蒙古、陕西、山西、河南及山东9个省（自治区），最后流入渤海。

黄河中上游以山地为主，中下游以平原、丘陵为主。由于河流中段流经中国黄土高原地区，因此夹带了大量的泥沙，所以它也被称为世界上含沙量最多的河流。但是在中国历史上，黄河下游的改道给人类文明带来了巨大的影响。

Because the middle reach of the river runs through the Loess Plateau, it brings with itself a lot of sand, so the Yellow River evolved as the sandiest river in the world. In Chinese history, the Yellow River has changed its course for several times, which brings tremendous impact on human civilization.

黄河是中华文明最主要的发源地，中国人称其为“母亲河”。每年都会生产十六亿吨泥沙，其中有十二亿吨流入大海，剩下四亿吨长年留在黄河下游，形成冲积平原，有利于种植。

The Yellow River is the major