PHOTOS 1. In upper left, see wing dam with open spillway 2. Tow = 4 barges + towboat 3. Heating system on top of barge to keep asphalt liquid
The Mississippi River extends approximately 2300 miles through the heartland of America from Minnesota to the Gulf of Mexico. It is fed by tributaries extending east from the crest of the Rockies, west from the crest of the Appalachians and south from Canada.
Once part of our nation, this many-branched waterway was immediately recognized as an important shipping route. The MIssissippi soon became our inland highway – a steamboat navigated its lower portion up to the Ohio River in 1817 and then in 1823 its upper portion all the way to St. Paul. In 1866, Congress gave the Army Corps of Engineers responsibility to maintain the channel, increasing the depth requirements over the years. At first, the Army Corps of Engineers removed snags, logs, and other obstructions. Later it built wing dams to close off side channels to raise the level of the main N-S channel. In the 1930’s a navigable channel measuring 9 feet was mandated -- this required creating a series of locks and dams, built for navigation (not flood control), extending along the upper river between Alton, Illinois and Minneapolis. Once completed, river transport hit the big time, with the tonnage of transport soaring into the realm of the inconceivable.
From the bluffs along Scenic Highway 35 winding from Prairie du Chien to La Crosse, we could see the broad expanse of the Mississippi. Stopping at what is called “Pool 9” with its wing dams and locks, we saw 4 immense barges chained together --extending about 100 feet in width and 750 feet in length. These barges carried a cargo of hot liquid asphalt from a refinery in St. Paul – to be delivered to Houston, Texas. The total voyage would take about 3 1/2 weeks even with the very high water and swift current. The barges and towboat pushing them from the rear progressed slowly through the lock as the water level descended to the height of the channel downriver.
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