In Chicago, urban kayaking has boomed thanks to the city's calm, easily navigable river surrounded by densely packed, scenic skyscrapers.

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This is the last navigable point up the river after boats have entered from the Atlantic.

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Developing Donlin Creek means barging equipment up the Kuskokwim River, navigable only six months of the year.

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NovaGold has tried to estimate for years how much it might cost to build a mine at Donlin, which requires barging equipment up the Kuskokwim River, navigable only six months of the year, in the face of extreme weather and environmentalists.

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The Canal Corporation operates a series of dams and locks on the river to create navigable channels.

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River dwelling tribes that number less than a thousand strong worry that when the diversion is through, the river will no longer be navigable and may see some Xingu tributaries dry out for good, impacting their way of life and a key route to the city of Altamira nearby.

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The river has been open to the public as a navigable waterway for decades, though it was encased by private land owned by timber companies and covered by hunting club leases and posted against trespassing.

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Three years before, environmentalist Joe Linton, George Wolfe of LA River Expeditions, and a few others had trespassed onto the then-closed river in an attempt to prove that the waterway was navigable by kayak.

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