Jim Colby provided this photo to show how an H notch tow fills a 600' lock. The H formation facilitates navigating the narrow Black Warrior River because it projects the rear of the towboat when the tow goes around bends in the river.
|Jim Colby commented on his post|
Holt Lock and Dam above Tuscaloosa, Alabama
|BlackWarriorRiver, Photo by Nelson Brooke, Flight by SouthWings.org|
"A series of fourteen locks and dams were built on the river in the late 1800s. In the 1930s, work began to replace those dams with a more modern series of four locks and dams." This dam replaced four of the older dams. [TuscaloosaNews]
Most photos of this dam don't have any water going through the spillway because they would want the water to go through the powerhouse. But here is one where they are having to spill water.
"The Project has one turbine that has a minimum hydraulic capacity of 1,000 cfs, and maximum hydraulic capacity of 11,200 cfs." The lift of the lock is 64.1'. "An average of three to five vessels passes through the lock daily....The total spillway capacity of the dam is 393,000 cfs at pool elevation 187 ft msl, and 639,500 cfs at pool elevation 206.4 ft msl."
|TuscaloosaNews, photo composite/Gary Cosby Jr.; The article has 31 photos.|
[The 80' high downstream gates were replaced during the Summer of 2018 by a $12m project. Each of the gates weighs 750,000 pounds.]
I did not read this Hydraulic Model Report, but I did spend some time studying these diagrams. The report has diagrams for gate openings of 2', 5', 10', 15' and Full. Below are the two 2' diagrams. The difference is the height of the tailwater's river bottom, 90' vs. 110'. According to the diagram above, they changed the front profile of the spillway and went even higher with the river bottom at 123'. How do you change the height of the tailwater river bottom? Dump a bunch of stone in the river?
Jeff Wilkes: She’s just come off of the Tenn Tom . That’s referred to a H pattern