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National

The mighty Mississippi: Defining a river

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Lee Powell/The Washington Post

The Mississippi River stretches for 2,320 miles, rolling by 10 states, bisecting a nation. It is the world’s fourth-longest river, passed only by the Amazon, Nile and Yangtze.

You can tell a lot about the nation’s infrastructure needs by taking a journey down the river, because the Mississippi has it all: locks, dams, bridges, levees. For those unfamiliar with the ways of the river, the words seem foreign.

Here’s a guide to the Mississippi’s language.

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The Washington Post

Levee, from French, means "to raise," because the ridge of dirt is raised higher than its surroundings.

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Dustin Boatwright/The Little River Drainage District

When a levee breaks, flooding follows. The Mississippi typically floods from December to July.

Lee Powell/staff

A lock is a passageway for vessels to navigate a river that changes elevation. On the Mississippi, there are 29 locks, all north of St. Louis, where the river is really a series of pools. In all, these locks provide more than 400 feet of lift.

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Commercial river traffic such as towboats and barges use locks the most. Despite the name, a towboat pushes barges filled with cargo such as sand or chemicals. Locks on the Mississippi have just enough room for 1,200-foot barges or 600-foot ones.

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Lee Powell/The Washington Post

On the left, a towboat with barges enters the lock chamber.

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Lee Powell/The Washington Post

Gates close at both ends, allowing water to fill the chamber.

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The water level rises until it matches the river height at the exit.

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Lee Powell/The Washington Post

The lock gate opens, and the towboat and barges are on their way. A passage such as this can take about half an hour.

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This animation shows that same lock process sped up. This barge is going from a higher to a lower elevation.

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Lee Powell/The Washington Post

Without locks, boats and barges would have to navigate rapids such as these — a dangerous and impractical journey.

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Lee Powell/The Washington Post

These are chevron dikes, man-made structures that concentrate river flow and help with navigation.

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Any mention of the Mississippi has to include Mark Twain, the pen name of Samuel Clemens. The author grew up in Hannibal, Mo., and worked as a steamboat pilot.

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Lee Powell/The Washington Post

"One who knows the Mississippi will promptly aver — not aloud, but to himself — that ten thousand River Commissions, with the mines of the world at their back, cannot tame that lawless stream, cannot curb it or confine it, cannot say to it, Go here, or Go there, and make it obey; cannot save a shore which it has sentenced; cannot bar its path with an obstruction which it will not tear down, dance over, and laugh at."

— Mark Twain, "Life on the Mississippi"