(Updates with Alon statement)

May 11 (Reuters) - Heavy flooding in the U.S. Midwest shut Ohio River terminals, limited barge movements and threatened to disrupt refinery operations along the Mississippi River to the Gulf of Mexico on Wednesday.

There are 10 refineries, including the second-largest U.S. refinery, located along the Mississippi River, that can process 2.4 million barrels per day of oil, or 13.7 percent of the country's refining capacity.

(Graphic: r.reuters.com/gyt49r)

Valero Energy Corp's (VLO.N) and Motiva Enterprises (RDSa.L) refineries in St. Charles Parish, Louisiana, west of New Orleans, will be flooded if the Morganza Spillway, which would send floodwaters from the Mississippi down the Atchafalaya River, is not opened, the St. Charles Parish emergency preparedness director said on Wednesday. [ID:nN11256696]

Scores of U.S. heartland rivers from the Dakotas to Ohio have flooded following a snowy winter and heavy spring rains, feeding near-record crests on the lower Mississippi River.

Valero Energy Corp's 180,000-bpd refinery in Memphis, Tennessee, continued operating on Wednesday in the center of the worst flooding where high waters forced evacuations in residential areas. The river crested near 48 feet (14.6 meters) on Tuesday at Memphis.

The U.S. Army Corp of Engineers was planning to open the Morganza spillway by early next week, which will send flood waters from the Mississippi to the Atchafalaya River.

Alon USA Energy (ALJ.N) said on Wednesday its 80,000 bpd Krotz Springs, Louisiana, refinery may have to shut down if the spillway is opened. At the very least, Alon expects reductions in production for several weeks due to crude supply disruptions. The company said that within two weeks of opening the spillway, the refinery may be surrounded by flood water. Safety requirements or logistical problems may require idling the plant altogether.

REFINERIES AT RISK FROM FLOODS (in bpd)

*Alon USA Energy (ALJ.N) Krotz Springs, Louisiana : 80,000

*Chalmette Refining (XOM.N) Chalmette, Louisiana: 192,500

*ConocoPhillips (COP.N) Belle Chasse, Louisiana: 247,000

*Exxon Mobil Corp (XOM.N) Baton Rouge, Louisiana: 504,500

*Marathon Oil Corp (MRO.N) Garyville, Louisiana: 436,000

*Motiva Enterprises (RDSa.L) Convent, Louisiana: 235,000

*Motiva Enterprises (RDSa.L) Norco, Louisiana: 234,700

*Murphy Oil Corp (MUR.N) Meraux, Louisiana: 120,000

*Valero Energy Corp (VLO.N) Memphis, Tennessee: 180,000

*Valero Energy Corp (VLO.N) St. Charles Louisiana: 185,000

http://www.reuters.com/article/2011/05/12/usa-flooding-refineries-i...