Saturday, June 28, 2014

Amazing Engineering Still in Use: Lock & Dam 15, Mississippi River

This post will be a bit different than previous ones in Urban Decay. Here we will highlight engineering and infrastructure that is still is regular use and has been maintained eight decades after construction. Lock & Dam 15 are on the Mississippi River at Rock Island, Illinois.

First, a short introduction. A river flows downhill towards the sea or a lake. In flat terrain, it flows slowly, and, provided water depth is adequate, vessels can traverse both upstream and downstream.  But, as the terrain becomes steeper, a vessel has more and more trouble moving upstream because of the increasing current. Therefore, to aide navigation, engineers build dams across the river to create a series of lakes or pools. The river ends up looking like a series of terraces with dams marking the lower (downstream) edge of each pool. To let ships pass, a lock or boat lift must be built at each dam. Locks are also used to bypass an area of dangerous water, such as cataracts or waterfalls.

Click the link for an excellent Corps of Engineers brochure on Upper Mississippi River locks and dams.  "The Upper Mississippi River – Illinois Waterway System includes 37 locks and 1,200 miles of navigable waterway in Illinois, Iowa, Minnesota, Missouri, and Wisconsin. The 9-foot Channel Navigation Project was largely constructed in the 1930s and extends down the Upper Mississippi River from Minneapolis-St. Paul to its confluence with the Ohio River and up the Illinois Waterway to the Thomas J. O’Brien Lock in Chicago. "The maintenance needs of the aging infrastructure are increasing at a rate much greater than the operations and maintenance funding provided for the system." This is a polite way of saying that Congress has been grossly underfunding maintenance for decades.  It is a symptom of our race to the bottom.

"9-foot Channel Navigation Project" means that barges with a draft of 9 feet can transit the system. In the south, the 9-ft channel begins at Baton Rouge. Ocean-going ships can travel up the Mississippi as far as Baton Rouge, but further north, cargo must be transferred to barges. I do not know haw a depth of 9 ft was selected in the 1920s, when the ambitious project was conceived.
Here is the Lock & Dam 15, with the dam, lock, and railroad bridge spanning the Mississippi River (undated photograph from U.S. Army Corps of Engineers). Across the Mississippi River is Davenport, Iowa.
This is the newly-built project in 1933.
Today, the scene looks almost the same, with the elegant Clock Tower building serving as the office for the U.S. Army Corps of Engineers on Arsenal Island (2009 photograph courtesy U.S. Army Corps of Engineers).
The main lock is 110 feet wide by 600 feet long. A lock is a basin of water that allows boats to change their elevation and pass from one water level to another. Gates open and the boat enters. The gates close and the water either drops if they are heading downstream or rises if they are moving upstream. Then the gates open and the boats proceed on their way. In this example, the barges contain coal and are moving upstream. The top photograph shows the gates opening on the downstream side. Coal is an example of bulk cargo that is most economically and safely carried by barge. Rock, gravel, petroleum, cement, wheat, soybeans, and extra-large machine parts or steel constructions are other examples of materials that can be carried by barge. As long as there is a nearby waterway, barges are much more efficient than trains or trucks.
This is a 1936 photograph of the dam at Rock Island. The water flow can be blocked by a series of roller gates that roll down a track to a specified elevation. "The 1,203-foot-long movable dam is the largest roller dam in the world consisting of 11 non-submersible 100-foot-long roller gates with 11 control houses. Nine gates are 19 feet 4 inches in diameter and two are 16 feet 2 inches."
These photographs show how the roller gates operate. They fit in an inclined slot and literally roll up or down the track to the specified elevation in the river. The advantage of this design is the cylinder is strong and can withstand impact from ice and logs. Also, a relatively low-power electric motor can roll the cylinder up or down. I do not know how they seal the ends, or what happens if debris lodges on the track.
These are photographs of hydraulic physical models at the famous Iowa Institute of Hydraulic Research at the University of Iowa in Iowa City (Mavis 1939). The Iowa River flows through campus, dividing it into east and west sections. In the 1930s, the river provided the water that was used for the models. My father noted in his diary that sometimes the river flooded the subbasement, and work was suspended until the water level dropped again. Also, sometimes the model froze in winter (he noted a period of almost two weeks in February of 1937 when morning temperature was -17˚ F.). In that era, many of the students showered in the laboratory - they must have rented rooms in rooming houses without bath facilities or without hot water. How times have changed; can you imagine contemporary students living with even minor inconvenience?

In the first photograph, the template for the bed is made of wood. Fifty years later, the construction process is almost identical, except that the templates are cut from aluminum.
This shows a model with three roller gates, of which the center unit is raised (Morang 1937).
This shows the flow pattern based on a time exposure photograph of confetti. This method of visualizing flowwas used at least through the 1990s.
This is a flume with a model of the Marmet Dam on the Ohio River. Notice the turbulence downstream of the gate. A flume is a long glass box which allows the technicians to see the flow from the side. Flumes are still in use in laboratories around the world.
Here are students and faculty of the Hydraulics Laboratory in 1936 or 1937. My father noted that in some classes, there were many Chinese students. Even back then, the government of Chiang Kai-shek was sending technical students to the United States to learn about engineering and science.

This was the era before electronic computing machines, and all observations were recorded manually on graph paper. We built much of the nation's infrastructure like this, based on sound engineering by hard-working engineers, scientists, and technicians. And we are letting it crumble away through neglect, political infighting, corrupt politicians, funds siphoned away to the military-industrial complex, idiotic concepts of how infrastructure projects are "socialism," and national stupidity. (And in the meantime, the Chinese have built magnificent highways and bridges, high-speed rail to Tibet, and initiated the China Railway Express, a new railway line from China to Europe. Guess who is on the ascendancy and who is sinking into third world decay.)

References

Mavis, F.T. (editor). 1939.  Two Decades of Hydraulics at the University of Iowa, Abstracts of Theses, Publications, and Research Reports. University of Iowa Studies in Engineering, Bulletin 19, Iowa City, IA.

Morang, C.N. 1937.  The Effect of Symmetrical and Unsymmetrical Roller Gate Operation on Discharge Coefficients. M. S. thesis, State University of Iowa, Iowa City, IA, 68 pp. 


Photograph No. 1 is from the Library of Congress:  

TITLE: Mississippi River dam #15, general view of completed dam, view from top of Clock Tower building
SUMMARY: Photograph shows dam across the Mississippi River and Davenport, Iowa. The Government bridge, which carries railroad, automotive, and pedestrian traffic, is in the foreground. The Davenport city skyline is in the background.
DATE: 20 March 1934
This image is available from the United States Library of Congress's Prints and Photographs division under the digital ID ppmsca.17351

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