Muskogee County Emergency Management spokeswoman Tricia Germany says the barges were carrying fertilizer. Germany says the concern was that the barges would block the water flow through the dam, but said the water initially appeared to be flowing well.
The barges have been floating out of control, on and off again, since Wednesday night near the town of Webbers Falls. Aerial footage from the Oklahoma City television station KFOR showed the moment of impact shortly before noon Thursday.
Officials had issued a mandatory evacuation order because of flooding concerns Wednesday night for the 600 residents of the town, which is located about 70 miles southeast of Tulsa.