Minnesotans, like most Americans, don't think much about the transportation system around them -- the roadways, railways or runways -- until they are stuck in traffic, stopped while a train passes or delayed on the tarmac for a flight home.

The fourth "R" of transportation, the rivers, are like that, too. We forget about the importance of the Mississippi River, an essential "water highway" for the central United States, until it shuts down from flooding or drought, or a lock or dam failure that results in higher costs for food, electricity or other goods.

Why is the Mississippi mighty for Minnesota? Grain harvested here travels on the Mississippi River to the Gulf of Mexico, where it enters the world export market. Rock salt for safer winter driving in our state travels up the river from Louisiana. Just last year, Minnesota-based Cargill shipped 90 different commodities up and down the rivers.

The economic impact of the U.S. waterways transportation sector is significant: 12,000 miles of waterways move one-sixth of the nation's freight. In 2010, that was 566 million tons of cargo valued at more than $152 billion, saving shippers, growers and consumers $14-per-ton vs. other transportation modes.

And moving that cargo on the rivers relieves congestion, benefits air quality and saves fuel. A typical 15-barge tow carries the load of 216 rail cars and 16 locomotives, or the equivalent of 1,050 tractor-trailers.

Lake and reservoir projects associated with the dams on the waterways provide municipalities with fresh water sources. The dams help prevent floods, ensure irrigation for farmers and ranchers to produce a secure food supply, support national security, and offer abundant recreational activities.

Our nation's waterways are a reliable transportation logistics network because of the vision of past Congresses and hard work of the U.S. Corps of Engineers to maintain this vital system. But the past several years have proved challenging for the Corps to manage -- record flooding followed this year by severe drought, in addition to dwindling funding for lock and dam infrastructure, much of which has outlived its economic design life of 50 years. In fact, many of the locks and dams here on the upper Mississippi River are more than 70 years old and in dire need of repair.

In September, I testified before the U.S. Senate Environment and Public Works Committee that by failing to properly fund needed investment in our waterways' infrastructure, we are on a dangerous path toward catastrophic failure of our river system and our competitive means of commerce.

Ironically, for five days prior to my testimony, Lock 27 near St. Louis had been closed to navigation, grinding river traffic to a halt and costing the nation millions of dollars. Almost all of the barge traffic moving into or out of Minnesota must pass through this lock, as well as more than 20 additional locks going north to Lock 1 in Minneapolis. Nearby, in Missouri, Lock 25 is scheduled to close for repairs for one-third of the month of October during the height of the Midwest harvest.

And just after my testimony, six senators from Illinois, Missouri and Iowa sent a letter to the committee urging needed action on water-resources legislation to advance the waterways system's infrastructure.

Despite efforts of the navigation industry to modernize operations for a 21st-century economy, on the rivers we rely on 1930s technology that is on the brink of collapse. Some of the lock and dam projects already authorized by previous Congresses will not be addressed in this century; no new construction or major rehabilitation projects are scheduled until 2053.

The system's deficiencies are most glaring at the Olmsted Lock and Dam project on the Ohio River. Originally authorized by Congress in 1988 at $775 million, the project was to be completed within 12 years. Nearly 25 years later, it is nowhere near complete and has ballooned to more than $3 billion, paid half by navigation users and half by taxpayers.

If the process to construct these critical navigation projects does not change, and if the broken investment funding model is not fixed, it is just a matter of time before a failure on the nation's waterways system could shut off large segments of our nation from effective river navigation. In Minneapolis, we are on the wrong end of the river for that to happen. Grain prices to farmers will fall. Crop input costs will rise. The price of coal for utilities will go up. Industrial salt costs for our roads will skyrocket. And thousands more large trucks will enter our crowded highways, creating congestion and safety concerns.

Infrastructure investment is about growth and revenues. It's about American jobs. And it is about staying competitive, as a nation, in the global marketplace. Yes, infrastructure costs money, but it should be viewed as investment. The cost of failing to act is significantly higher and will take years to reverse. As Minnesotans -- and as Americans -- we simply can't afford that.

Rick Calhoun is president of Cargo Carriers, a business of Cargill.