Anyone wondering the importance of the nation’s riverways should look no further than the Midwest, where a backup to beat all backups has been going on the last few days.

Most of it is dispelled now, but for a while the Mississippi River looked like a parking lot with dozens of tows and hundreds of barges waiting to get through damaged Lock 27 in Granite City. Some of the vessels were moored all the way north of Alton, miles away. Other operators were simply porting wherever they could find room until they could make their way downstream (or, for some, upstream).

Obviously anyone looking at a map can see all the waterways north of Granite City that feed into the Mississippi, including from the Illinois River, which carries a lot of freight. What they might not realize is that roughly half the nation’s farm exports pass through those locks, making the shutdown worrisome at a time growers are completing corn harvests.