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Locks key to river navigation

ARSENAL ISLAND -- Perhaps it's true you can't fool Mother Nature.

However, the guys who operate Lock and Dam 15 on the Mississippi River at Rock Island prove every day that with a few million tons of concrete and steel, you can, at least, manipulate her.

More than a century ago, the local section of the upper Mississippi River was the waterway's most treacherous area for navigation because it was one of the most narrow and shallow parts of the river.

It also had the Rock Island Rapids -- treacherous chains of rocks snaking out from the shoreline into the channel. They caused many steamboat wrecks over the years, despite the work of specially trained riverboat pilots, paid solely to know the river bottom well enough to steer vessels safely through the rapids.

Now, 161 years and $7.5 million later, tons of cargo pass every day of the shipping season through the lock chambers on mammoth barges, and countless gallons of water spill under the dam's roller gates.

Also each year, thousands of tourists and curiosity seekers stop at the lock and dam to watch from the shore or through the glass windows of the visitors' center, as the technological wonder lifts and lowers vessels of all sizes and cargoes, using only gravity and a bit of human ingenuity.

Lock and Dam 15 was the first of the existing 29 dams on the upper Mississippi. It opened in the spring of 1934 -- 161 years after the government commissioned the first professional survey of the Rock Island Rapids area by then-lieutenant Robert E. Lee. It cost $7.5-million to build Lock and Dam 15.

The problem areas of the upper Mississippi were dredged three times. In the late 1870s, the channel was dredged to 4 1/2 feet deep. In 1907, Congress authorized money to to deepen it to six feet. Then, after the WWI, it was deepened to nine feet to accommodate larger vessels.

Lock and Dam 15 is self-sufficient. It uses water power to generate the electricity it takes to raise and lower the roller gates, operate valves and open the doors to the locks. Left over energy helps power the clock tower building and parts of the Rock Island Arsenal.

While valves to man-made tunnels are opened electronically, the lock chambers are filled and emptied by gravity. It pulls water from the full chamber to the empty one, accomplishing the Herculean task of lifting enormous barges loaded with tons of cargo, so towboats can continue pushing them to their final destination.

By redirecting the flow of water through gravity, man tricks Mother Nature into doing work for him, work that's made safe river navigation possible, despite the natural treacherous state of this part of the Mississippi.

Interesting Facts about Lock and Dam 15

The United States stole the blueprints for lock and dam technology from Germany during World War I. Germany later sued for the patent, and the U.S. had to pay for it.

No electricity or pump is needed to fill or empty the lock chambers. Water moves by gravity, through a system of man-made tunnels.

You don't have to know how to swim to work at Lock and Dam 15.

Lock and Dam 15 is the only facility of its kind on the upper Mississippi River that has two lock chambers. Original plans called for all 29 locks to have two chambers, but the second chamber was installed only at Lock and Dam 15, the first one to be built.

On average, the lock is opened and closed up to eight times a day during the shipping season. About 60 percent of the time, the cargo being transported is agriculturally related.

The main lock uses 16,330,400 gallons of water.

When Lieutenant Robert E. Lee (later a Confederate general) first surveyed and mapped the Rock Island Rapids in 1837, he and his staff worked from atop two riverboats that had sunk up to their second decks. They liked to catch catfish by casting lines out the ``office'' window.

Each steel lock door weighs 90 tons.

It cost $7.5 million to build the lock and dam in the early 1930s.

-- By Marcy Norton (January 22, 1998)

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