
The Memphis gauge fell to the minus-5 foot low-water threshold on August 30, and the Coast Guard's 9-foot draft requirement limits barge loads. A 9-foot draft carries about 900 tons, versus about 1,500 at normal draft.
An agricultural economist said grain terminals will need more barges, trucks or rail, adding cost that pressures basis.
Cutting barge loads by about 200 tons per foot raises per-ton shipping cost, which weakens corn and soybean basis at river terminals.
Not enough comparable past events yet for a historical read.
After 359 past bearish logistics events, Corn moved a median -0.3% over 5 sessions (44% higher; middle half -1.5% to +1.5%), and -0.5% over 20.
After 297 past bearish logistics events, Soybeans moved a median +0.3% over 5 sessions (54% higher; middle half -1.5% to +1.8%), and +0.7% over 20.
Moves of each commodity's benchmark from the last close before the event. Historical reads pool past events of the same kind; they describe what happened, not what will. Not investment advice.