Sunday, August 19, 2018

The Olmsted saga (Part 1 of ?)

The M/V Steve Golding transits the riverward lock at the Olmsted Locks and Dam the morning of July 25, 2018. The Steve Golding was pushing four barges from Mount Vernon, Ind., to Memphis.

In the novel “The Lost World”, the sequel to “Jurassic Park”, Ian Malcolm and Doc Thorne are walking through the remains of InGen’s embryo lab at Site B on Isla Sorna. This was where the real work was done in using DNA from dinosaurs and from modern amphibians to produce the animals that tourists would see at Jurassic Park on Isla Nublar.

Doc Thorne wondered why such a large setup was necessary when the Isla Nublar guided tour gave the impression that eggs were fertilized and hatched there. Malcolm replied:

“And if you think about it, it couldn’t possibly be true. Hammond was claiming to manufacture extinct animals using cutting-edge technology. But with any new manufacturing technology, initial yields are low: on the order of one percent or less.”

The first time you try a new process, there will be a learning curve where things don’t happen on time or within budget. That curve can be pretty steep. Don’t ask me to read some of the first news articles I wrote more than forty years ago and praise them for their cleverness or their precision.

Those thoughts went through my head the morning of July 25 when I and several other journalists stood at the construction site of the Olmsted Locks and Dam and listened as people from the Corps of Engineers and from the inland marine industry talked about the innovative construction methods used to build what will be the largest and by far most expensive navigation dam on the Ohio River.

If I had allowed my mind to run a little more with that thought, I would have recalled how it took about 25 years for the state of West Virginia to build a two-lane bridge across the Ohio River at Huntington. As with the Olmsted project, that one involved designs and processes that were new to large bridges in this area, but that was not the only thing that delayed that bridge’s construction.

But thirty years and about $3.1 billion later, the Olmsted Locks and Dam is nearing completion. When it raises its pool and puts Locks and Dam 53 and Locks and Dam 52 out of service, it will mark the end of a process that began in the 1940s. Actually, it began in the 1930s, just a few years after the old system of low-lift wicket dams was finished.

The 10-20

The Olmsted Locks and Dam project is at River Mile 964.6. That places it 964.6 miles downriver of The Point in Pittsburgh, where the geographers tell us the Ohio River is formed when the Allegheny and Monongahela rivers meet. The Olmsted project is 16.9 miles above the mouth of the Ohio at Cairo, Ill. It’s also about 2 miles below Locks and Dam 53 and 25.7 miles below Locks and Dam 52, both of which Olmsted will replace.

Olmsted is also 29.6 or 30.6 miles below the mouth of the Tennessee River, depending on where you measure it, 41.6 miles below the mouth of the Cumberland River and 46.1 miles below the Smithland Locks and Dam, where its pool will end.

The Ohio River below Smithland is a different creature than it is for most of its length, especially the part above Louisville. It’s wider and shallower in most places, and it’s less likely to need dams to maintain year-round navigation. But dams are needed about half the year, so Olmsted is designed differently so it can account for that fact.

That different design is part of the reason Olmsted is so expensive and took so long to build. Innovative engineering and construction methods contributed to that, too.

The old Ohio River dam system, of which 52 and 53 are the sole remaining members, relied on wickets to maintain a navigable pool. Wickets were large oak timbers that could be raised to hold back the river when a dam was needed and then lowered to the river bed when it wasn’t. Modern Ohio River dams, beginning with New Cumberland in the Pittsburgh District, Greenup in the Huntington District and the rebuilt McAlpine in the Louisville District, instead rely on tainter gates.

The newer dams have a fixed sill, and tainter gates control the flow of water going over it. The gates swivel on hinges built into the dam piers. They are raised to let more water through the dam during period of higher flow and lowered to reduce the flow when flow is low. At some dams the gates are shut completely when the flow is very low but still enough to feed a hydroelectric power plant built on the shore opposite the locks.

Olmsted will have both. It will have a wicket section, known as the navigable pass, that’s 1,400 feet wide, and it will have five tainter gates. When flow is low, the wickets will be raised and the tainter gates will control river flow. When flow is high enough that the dam is not needed to provide the required depth for a navigable channel to Smithland, the wickets will be lowered and boats will travel through the navigable pass.

When the wickets are up, boats will have to use the locks on the Illinois side. Each lock is 110 feet wide and 1,200 feet long.

Olmsted sits near the hub if the inland river navigation system. The point where the Ohio and the Upper Mississippi meet there at Cairo is one of the busiest in the nation. Thus it was important to keep traffic flowing while Olmsted was under construction. Typically that would have been done by building cofferdams in the river so construction workers could do their jobs in dry conditions unaffected by river current or river traffic. But the Louisville District of the Corps of Engineers that would not work, so they used a method called in-the-wet that had been used in deepwater environments but never before on a large navigation project in a river. And that’s where the problems started.

Up Next: Innovation and setbacks