Barge operators say they're losing tens of thousands of dollars in revenue a day because flooding has brought freight traffic to a standstill on a stretch of the upper Mississippi River.

In a battle to contain the water, the Army Corps of Engineers closed 13 locks on June 12.Sangbags are piled high in the town of Hamburg, Ill., in an attempt to keep floodwaters from the Mississippi River from claiming more homes. (M. Spencer Green/Associated Press)

Nine locks remained closed Saturday on a 345-kilometre stretch of the river between Illinois City, Ill., and Winfield, Mo., northwest of St. Louis.

More than 100 barges loaded with grain, cement, scrap metal, fertilizer and other products are stranded. The shutdown is expected to last a few weeks and involves primarily non-perishable goods.

The crest of the river was still moving downstream on the weekend and dozens of towns near the waterway were under a flood watch.

The rush of water broke or spilled over more than two dozen levees from Iowa to Missouri earlier in the week, submerging small towns and large tracts of prime farmland.

Among the inundated communities is Lincoln County, Mo., where 300 to 350 homes were flooded after the water flowed over or through the levees.

The floodwater is receding in Iowa, but slowly. Flood damage to crops in the state could reach $3 billion US, according to Iowa's agriculture secretary.

Other states affected by flooding, the worst the Midwest has seen in 15 years, include Indiana, Illinois, Wisconsin, Minnesota and Kansas.

So far, 24 deaths have been blamed on the flooding and violent storms since May.

With files from the Associated Press