Steel Corrosion in the Harbors of Lake Superior
On February 8th, I attended a speaker series put on by journalist and science communicator Marie Zhukov, called River Talks. Gene Clark a coastal engineer specialist, and Chad Scott an AMI consulting engineer discussed with the audience about the very real steel corrosion problem happening currently in Lake Superior.
Steel corrosion is a common issue among salt water harbors due to the saline breakdown, yet for freshwater corrosion it’s very rare. At first the problem was written off as electrochemical corrosion, but after being brought to court with evidence of corrosion as far as ten feet below the water line; there was a much bigger problem here.
Chad who originally discovered the corrosion problem while diving in the harbor asked for a grant from the state of Minnesota to investigate the problem further.
99% of people didn’t know about this problem and they believed it was time for the experts to take a look. Chad and his team hired five national and international experts on corrosion and they all immediately agreed this is an abnormality in a fresh water body like Lake Superior.
Gene stated, “they were awe struck they hadn’t seen anything like this in other Great Lakes ports”, so why was it affecting Lake Superior so heavily?
The possible causes they brainstormed for the corrosion occuring were things like dissolved chlories from de-icing salt, or potentially the water chemistry of Lake Superior. Yet, what they found was different.
Their colleague, Brenda Little, senior scientist for Marine Molecular Processes in the Naval Research Laboratory’s (NRL’s) Oceanography Division in Stennis, Mississippi discovered that iron oxidizing bacteria adheres itself to a piece of steel if there’s more stratches and cracks. She theorized that ice from Lake Superior every winter slammed into these growths and the bacteria would adhere to the wholes, creating corrosion.
Gene described this work as “the most interesting” he’s ever worked on in his lifetime. Chad got to work on figuring out a solution that would be durable through the four intense seasons that occur every year in Duluth. He came to a conclusion that a panel system only works in fresh water and should last around 50 years.
Gene discussed with us that the rate of corossion has increased heavily since the 1970s so they had to implement this solution quickly an efficiently. Industries affected by this corrosion problem like the harbor’s coal docks, pay around $3,500 per foot for a new steel wall.
I asked Chad during questioning, “I’m assuming it’s easier to fix or put in the panels during the summertime, is it still doable in the winter?” He explained that it’s still an option to work on them in the winter, just a lot more time consuming which results in the industries paying more money.
From starting with no believers, to having companies paying thousands to fix this rare problem in the harbors of Lake Superior, Chad and Gene along with their colleagues are very proud of their work.
As a Duluth citizen, it’s comforting knowing that environmental issues like this aren’t being given up on and having effort put into them for the greater good of not only our environment but also the industries of Duluth. There could be more potential findings on breakthrough research like this, so check them out!
Dr. Little came to work for the Navy in 1976 at what was then the Naval Ocean Research and Development Activity (NORDA…www.nrl.navy.mil
Marie Zhuikov: UW-Sea Grant
firstname.lastname@example.org, (715) 919–2154
Gene Clark: UW-Sea Grant Institute
email@example.com, (715) 392–8525
Chad Scott: AMI Consulting Engineers P.A.
firstname.lastname@example.org, (218) 727–1206