The Mississippi River is running low, and shoaling is causing numerous groundings and short-term closures of the river, the U.S. Department of Agriculture (USDA) reported Thursday.

Lower-than-normal rainfall in the central U.S. has caused sediment to accumulate in the Mississippi River. The lack of rain and subsequent shoaling has affected the narrower, shallower upper Mississippi more significantly. When barges ground, a section of the river may need to be closed in order to facilitate their removal, followed by dredging to remove the shoaling.

On the wider and deeper lower Mississippi River, the Coast Guard has restricted tow size and barge drafts on a nearly 400-mile section from New Madrid, Mo., to Lake Providence, La., due to low water conditions. Down-bound traffic is restricted to daylight only in the Lake Providence area.

Traffic continued to move in spite of delays, the USDA said, and 26.5 million tons has been moved by barge this year to date, representing a tonnage increase of nearly 20% on the five year average.

For the week ending October 17, barge grain movements totaled 760,040 tons, down 14% from last week, and up 25% from the same period last year. For the week ending October 17, 472 grain barges moved down river, down 14% from last week; 893 grain barges were unloaded in New Orleans, up 22% from the previous week.