Dam Mississippi

Modern river boat trade on the Mississippi was made possible only by some fairly major efforts from the US Army Corps of Engineers. A minimum depth of 9 feet was deemed to be required for safe passage. For the Upper Mississippi River to meet this standard a series of navigation locks and dams was required, authorised in 1930.

It was a big project, because this is a big river. A variety of vessels use the locks during the navigation season, from large tow boats with barges to teeny little canoes. The locks provide vertical lift ranging from a few feet to over 12 feet. Cargo is often grain, with the Mississippi River still providing a major artery for grain from the Midwest to reach domestic and international markets. More than 9,000 recreational craft use the locks each year.

I'm sure it was quite different when Mark Twain was a riverboat pilot on the Mississippi. He had to memorise the safe channels in both directions for the entire length of the river and the depth was checked with constant soundings. In fact, that's where the pseudonym Mark Twain came from. Safe depth was two fathoms. The man taking the sounding would call out "Mark" at the first fathom, and "Mark Twain" at the second fathom. Thus, "mark twain" means "safe depth."

As we drove alongside the river we passed a river barge making its way south and decided to stop at the next lock to watch the docking procedure. As a tourist experience this was both quite exciting and extremely slow, a bit like watching The Terminator entirely in slow motion. There was an initial flurry of activity as the barge approached. The guy who was mowing the lawns was hussled into the office as all the staff assumed their docking stations, where they waited for the next 45 minutes as the barge slowly drew closer.

Eventually even the staff started to get bored, so they opened the gates a good 25 minutes before the barge was in any danger of getting close to the lock.

Coming in on a sharp angle, the pilot had to perfectly line up the 9 barges lashed to the front of the tow boat with the lock ahead. It was impossible to appreciate from a distance how difficult and important this task this was. We had no idea how tight a fit this was going to be.

A bit bored by the freeze-frame approach of the barge I paused briefly to take a photograph of a passing freight train. It was much more exciting. A few loud toots of the horn, a sound like a thunderstorm with the palsy and it was all over in under two minutes. It was a stark contrast to the stately, almost imperceptible, progression of the barge docking.

There's a chart next to the dock. It helpfully points out how much more a river barge can carry than a freight train. It's a lot, but I couldn't help noticing that freight trains move a whole lot faster. You wouldn't want to carry time sensitive goods on the river, or take on staff that are too old - just in case they reach retirement age before the end of the journey.

Even as it came closer we didn't quite appreciate the snugness with which the lock would fit the barges.

Only when they clanged against the wall and were slowly guided into the lock by staff tugging on ropes did we realise that even a very skinny and determinedly suicidal person would have trouble squeezing into the gap on either side. This load had been built to fit like spandex bike shorts.

It's pretty primitive technology. Twelve big, rusty steel buckets are lashed together with cables and then pushed along by a boat.

There are only a handful of staff on the barges. It must be tough work for the muscle men. Long periods of boredom interspersed with bursts of hard manual labour while wearing uncomfortable and unfashionable little plastic floatation devices. The guy on the barge is asking the guy on the dock what the temperature forecast is for that night. Suddenly I remember that even in Mark Twain's day the riverboats ran 24 hours. Surely they would do no less in the age of modern navigation methods? For the record, the nights in this part of the world are distinctly chilly, even in summer. I don't want to work on a river barge.

The load on this boat turned out to be too large to fit through the lock in one go. The first six barges were decoupled from the six behind. Then the boat backed out with six barges and the first lot were flushed out of the lock by themselves to wait for the rest of the load to catch up.

By this stage we were sufficiently bored and hungry that we decided to abandon ship and let the process continue without our supervision.