Now comes the Bakken pipeline

The Straits of Mackinac is a five mile wide expanse of water separating the Upper and Lower Michigan Peninsulas.With Lake Michigan to the west and Lake Huron to the east, this channel provides a vital link for Great Lakes commerce. The Straits also separate scenic Lower Michigan from even more scenic Upper Michigan.
In 1910, regular ferry service was initiated and access to the Upper Penisula for both tourism and minerals extraction became easier.  Talk of building a bridge across the Straits began in 1921, but it took until 1957 to get the job done.  The Mackinac Bridge is today a striking example of engineering achievement.   

A lesser known but similarly significant engineering project also impacts the economy and the environment every bit as much as the bridge.  In 1953 (as bridge construction was getting underway), two twenty-inch diameter pipelines were placed underwater across the Straits, parallel to the bridge alignment.  
The twin pipes are part of what is now (Canadian corporation) Enbridge Line 5, a 1098 mile long pipeline running from Superior, Minnesota to Sarnia, Ontario.   The pipeline is currently in the sixty-third year of its original fifty-year design life.  Operating pressure and capacity has recently been increased to 23 million gallons of petroleum products every day.
In light of today’s environmental standards and regulations, this is a truly remarkable story.   The twin pipes lie, totally exposed, on the floor of the channel.
They are subjected to the forces of the moving water which regularly changes direction and velocity.  
In 63 years of operation there has never been a spill of oil into the waters of the Straits.  This is extremely fortunate since oil escaping from this pipeline would quickly spread into both Lake Michigan and Lake Huron, and impact some of the most pristine lake environment in the country.  
Several hundred miles away near Kalamazoo, Michigan, another Enbridge pipeline (Line 6) does not duplicate the Line 5 safety record.  In July 2010, Line 6 ruptured and began pouring a petroleum product, diluted bitumen, into Talmidge Creek and ultimately into the Kalamazoo River.  It took eighteen hours before the leak was detected and the line shut down.  Over one million gallons of product were spilled. 
This is the largest inland oil spill in U. S. history.  To date, the incident has cost Enbridge an estimated $1.21 billion.  If such a spill had occurred in the line under the Straits of Mackinac, the costs could easily have been an order-of-magnitude higher.  
Enbridge has been subjected to costs and to disdain for the spill, and they have worked to repair the damage.  Their liability insurance coverage has been raised.  Oil spills are a cost of doing business for a pipeline company, to be avoided if at all possible, but more importantly to be kept away from bottom line impact.  
Conclusions that can be drawn from the Enbridge experiences depend greatly on your perspective.  One might be that Enbridge has a sterling safety record with Line 5 and must be doing things right.  Alternatively, you might see an environmental time bomb waiting to explode and conclude we are extremely lucky that something really bad has not yet happened.  The Line 6 disaster shows that accidents can, and will, happen and the transport of petroleum products always carries major risks.   
Now comes the Bakken pipeline.   Construction standards and environmental regulations are greatly improved since 1953.   However, Iowa is the land between two rivers; our land resources are both our pride and our economic lifeline.   
Every day the Bakken moves a step closer to reality.  We are in the process of creating our own environmental time bomb right in the Iowa soil.  
Yet, the even greater threat posed by all oil pipelines is that they perpetuate the carbon economy.  Once built, they create their own demand for the product they carry.   So long as we continue to build infrastructure to facilitate burning  fossil fuels, we march toward the one great environmental disaster that is climate change.    The Bakken was and continues to be a bad idea.