The Melvin Price Locks and Dam is downstream from the Chain Of Rocks Bridge that crosses the Mississippi River from Missouri to Illinois at Alton Illinois north of St. Louis Missouri USA. The lock and dam is named after Illinois Congressman Charles Melvin Price.
This lock and dam was built between 1978 and 1994. It is 1,160 feet long, with 9 tainter gates, each 110 feet wide by 42 feet high. These gates can hold the river waters back creating large lake like pools of water up stream from the dam. There are two lock chambers at Melvin Price to allow barges to bypass the dam. The main chamber is 1,200 feet long by 110 feet wide. The auxiliary chamber is 600 feet long by 110 feet wide.
There are 29 similar locks and dams on the upper Mississippi River. Due to the elevation of the land in the northern USA the river is all going down hill from mountains in Minnesota to low lands in Louisiana. Thus it is necessary to have these locks and dams in place to hold back the water of the river so it keeps the river deep enough to allow the river barges (which require a 9 foot draft to float fully loaded barge) passage down the river from one lock and dam to the next.
These barges carry millions of tons of commodities ~ wheat, soybeans, coal, corn, petroleum products, rice and many others ~ up and down the river each year. A typical barge carries 1500 tons of cargo, which is 15 times greater than a rail car and 60 times greater than one trailer truck. A normal barge float pushed by a Tug boat with between a 3000 and 5000 horse power diesel engine is three barges wide and five long for a total of 15 barges. On the lower Mississippi river the barge loads are much larger than 15 because they don’t have to go through any locks and dams.
You can tell that the water coming through the gates does not have much ice in it while the water up stream is almost completely covered with ice. The water is released below the river surface level thus preventing things like trees, trash and ice from stopping up the gates. Considering that the Mississippi River at normal level has 1.6 million gallons of water flowing down stream every second. There is LOT of water flowing in this image.
Nikon D40X with Sigma 10X20 ultra wide angle lens