We in the midwest have had a terrible drought this summer and even though we have had some rain since the beginning of August, that rain has not flowed to the Mississippi River. The river is very low and navigation is threatened. And navigation on the Middle Mississippi depends on water flowing from the Missouri. Let’s start with the Missouri, which in normal years supplies the Middle Mississippi south of St. Louis with 60% of its water. This year the Mississippi has drawn 78% of its water from the Missouri.
Governor Jay Nixon has asked the U.S. Army Corps of Engineersto trash its plan to reduce the amount of water it releases from 17,000 cubic feet per second to 12,000 cfs from the Gavins Point Dam in South Dakota in order to maintain water levels for navigation on the Middle Mississippi. He fears economic catastrophe is the Middle Mississippi River has to be closed to navigation for want of water from the Missouri.
This morning, the flood gage at St. Louismeasured 0.1 foot, Over the next several days it is projected to go up, and down and then way down to -0.6 feet. Any closing could happen when the Mississippi reaches -5 feet at St. Louis.
When the gage at Chester, Illinois gets down to about 1 foot, it is possible to walk out to Tower Rock, just south of Perryville, Missouri. The gage at Chester was a 2.4 feet this morning, which means you cannot walk out to Tower Rock without getting your feet wet.
Should the river fall below 5 feet at St. Louis the Corps of Engineers would consider blasting away rock formations in the bed of the river at Tower Rock and at Thebes Gap.
Update: On the bright side of the drought: with less water running off the land, fewer nutrients are making it to the river, and the dead zone in the Gulf of Mexico has shrunk this years.