Ag Weather Forum

It's been a tough summer and autumn for the Ohio River Valley. The Ohio River is the largest tributary of the Mississippi River, showing its water weight at the Ohio-Mississippi confluence at Cairo, Illinois. A Wikipedia note points out: "At the confluence of the Ohio and the Middle Mississippi, the long-term mean discharge of the Ohio at Cairo, Illinois, is 281,500 cubic feet per second (7,970 cubic meters per second), while the long-term mean discharge of the Mississippi at Thebes, Illinois, (just upriver from Cairo) is 208,200 cu ft/s (5,900 cu m/s). Thus, by volume, the main branch of the Mississippi River system at Cairo can be considered to be the Ohio River (and the Allegheny River further upstream), rather than the Middle Mississippi."

However, the drought which began back in mid-June has starved much of the 981-mile Ohio of moisture. Dryness and drought cover 96% of the Ohio basin. In the upper basin, southeastern Ohio and adjacent areas of West Virginia have been in extreme to exceptional drought -- the worst categories of the U.S. Drought Monitor assessment -- for the past 11 weeks. It was reported in late summer that Columbus, Ohio, had to access its emergency water supplies because of dryness. While September offered some beneficial rainfall, October precipitation was almost nonexistent: Cincinnati, Ohio, had less than 12% of its normal precipitation in October; Columbus, Ohio, had slightly over 10% of normal precipitation; and Dayton, Ohio, received only 8.5% of its normal precipitation in October.

The drought means the Ohio River is not able to contribute its usual volume to the Mississippi River at the confluence in Cairo, Illinois. Outdoor recreational information site Snoflo noted a big decrease from the Ohio River's average discharge on Thursday, Nov. 7, 2024:

"Total streamflow across the Ohio River was last observed at 74,850 cubic feet per second (cfs) and is expected to yield approximately 148,463 acre-ft of water today; about 38% of normal. River levels are low and may signify a drought. Average streamflow for this time of year is 195,815 cfs ..." the summary noted. (Data for the summary were sourced from public agencies.)

Precipitation forecasts through mid-November suggest moderate-to-heavy rainfall of up to 3 inches or more in the Tennessee and Cumberland rivers, which feed into the lower Ohio River and will provide some increase in volume for the Mississippi River. However, the upper Ohio basin is out of this track, with maximum precipitation amounts of only 1 inch or slightly more indicated. This mixed prospect for moisture in the Mississippi River's largest tributary offers very low prospects for significant improvement before winter.

For more details on barge traffic issues due to dryness, go here: https://www.dtnpf.com/…

Bryce Anderson can be reached at bryce.anderson@dtn.com

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