Mysterious Superior rust gets funding
Published on www.in-forum.com on January 3, 2006
DULUTH, Minn. – With $400,000 in funding approved, researchers
say they can make a good start in finding out what’s causing
the rust that’s been attacking the steel plates that line
the Duluth-Superior harbor.
The plates, which keep dirt out of the harbor and shipping
channels, were expected to last 50 years. Instead, they
are showing rust damage after only 10. The unexplained
rot, discovered two years ago, may cause them to fail
Duluth Seaway Facilities Director Jim Sharrow said the
problem isn’t found in other Great Lakes ports. The new
research project will first determine the extent of the
problem in the harbor.
“One of the things that we will be trying to do is to
map, carefully, the extent of that coverage,” Sharrow
said. “Is it really as severe in all areas of the harbor?
At the Oliver bridge, which is several miles above the
navigation channel, we’re not seeing this corrosion. We
don’t know if it has anything to do with shipping or just
the other activities of the population around the harbor,
or some other thing.”
They do know the problem is only in the inner harbor.
The plates are being replaced at the dock of a grain
elevator, and along the port entry in Superior, Wis.,
where ships follow the river channel into and out of the
“Part of the Superior entry is being replaced by the
Corps of Engineers, because of the excessive corrosion,”
Sharrow said. “Both of those projects are giving us some
corroded steel that can be reviewed and analyzed during
The Minnesota Legislature approved $100,000 for the study
last summer. In November, Congress approved another $300,000.
Sharrow said the investigators will take a close look
at whether something in the harbor water is causing the
“To study the water chemistry, and the condition of the
steel pilings of the various docks, as well as the on
going corrosion process,” Sharrow said. “We also will
be studying the rate of corrosion and various possible
methods of protecting the steel.”
The U.S. Army Corps of Engineers will lead the study.
Dave Bowman, a Corps project manager in Detroit, said
there are many theories about what could be causing the
rust, including electrical currents or micro-organisms.
He said he is coming to the problem with an open mind,
but he’s leaning toward an issue with water quality.
“Main things seem to be the water chemistry; water temperature;
or dissolved oxygen content – all those kind of water
quality parameters,” Bowman said. “So those are something
that we can fairly easily look at. You know people have
monitored that in the harbor for many years. And, those
will be the first things that we look at.”
The results could have a significant effect on the Corps’
“The one figure that I saw was over half of the steel
sheet pile in the harbor was corps’ structures,” Bowman
said. “So, yeah, we are potentially on the line for tens
of millions of dollars.”
Officials think they may have some answers within two