Friday, October 8, 2010

Lock Number 50 on the Ohio River


We are up to 78 locks on the Ohio River 79 is being built. I think the first and most of the old wicket locks are just stories on the Internet as is this lock above, it was blown away by Federal Contract in 1980 as were so many others.
From Federal Records:
"The first Federal improvements for navigation on the Ohio River came in 1824 with the removal of snags and sandbars. These measures were effective, but they were only temporary—new sandbars would appear after every flood. They also provided no relief against low water, which stopped navigation almost every year. The construction of a dam with a stable pool and a lock bypassing the dam would have ended problems caused by low water, but the shippers who needed the full width of the river for maneuvering were opposed to a dam.
A compromise solution was a movable dam that could be raised in times of low water to create a pool and lowered when the flow was adequate for navigation. The dams finally built had a series of Chanoine wickets, invented by Frenchman Jacques Chanoine, extending across the river. A system of 50 movable dams was built on the Ohio River between 1879 and 1929, making the Ohio navigable for its entire length at all times.
Each dam actually consists of a row of 300 or more little dams, individually hinged to a foundation on the river bottom. The wickets are constructed of heavy timber about 4 feet wide and up to 20 feet long. Raising or lowering the wickets is done by a crew on a maneuver boat that moves along the upstream face of the dam. A bar is connected to the back of each wicket with the free end riding in a groove in the foundation. To raise them, a grapple hooks a wicket and pulls it from the bed of the river. The bar slides up the groove to a niche, where it catches and supports the wicket upright against the flow of the river.
The advent of the more powerful diesel tow-boat after World War II greatly increased the size of the tows operating on the Ohio River. The tows were longer than the 600-foot locks and had to be broken into two segments for locking, more than doubling the time necessary for a lockage. A modernization program was begun on the Ohio in the 1950s to replace the old dams and the undersized locks with higher dams and longer locks, making the locking operation faster and less frequent. By 1977, all but the lowest four wicket dams had been replaced. It was at these old wooden dams that ice during the winter of '77 threatened structural damage."

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