Safety Board Reports On Webbers Falls Barges
The National Transportation Safety Board (NTSB) released a report on one of the most dramatic incidents of the floods of 2019, when two barges broke loose and careened down the Arkansas River, lodging against the Webbers Falls dam after raising fears of a dam breach and widespread flooding. Videos of the barges, both loose and lodged against the dam, went viral on social media.
In May 2019, the entire McClellan-Kerr Arkansas River Navigation System (MKARNS), including its tributaries, experienced heavy rainfalls, forcing upstream dams to make heavy releases. The captain of the Dennis Collins, pushing two barges of anhydrous ammonia, left the Tulsa Port of Catoosa on the Verdigris River April 30 but became increasingly concerned about the high-water conditions.
He initially tied off the barges at Mile 423 of the MKARNS and waited for river conditions to improve, but the vessel was running short of fuel, water and supplies. Using shore wires, the Dennis Collins and its two barges moored in the barge fleeting area on the left descending bank at Mile 394, where the Grand River meets the Arkansas River.
As flood waters on both the Grand and Arkansas rivers rose above major flood stage May 22, the boat’s crew added a third line to the barges. The boat kept its engines on reverse at clutch speed to reduce strain on the three fleet wires. At 12:13, all three wires broke, and four barges broke loose—the two anhydrous ammonia barges and two loaded with diammonium phosphate. Together with the Dennis Collins, they began to float downriver. The Dennis Collins’ stern swung to starboard and into the river, and the captain ordered the crew to let go the lines connecting the two diammonium phosphate barges. Within about three minutes, the Dennis Collins’ antennas struck nearby power lines, disabling wheelhouse equipment, including the electronic chart system, radios and AIS transmitter.
Using his cell phone, the Dennis Collins’ pilot contacted the Muskogee Oakley Terminal on the Arkansas River and asked if it would catch the loose barges. At 12:32, the port captain went to the towing vessel Legacy, got it underway, and caught the barges five minutes later just above Mile 393 on the Arkansas River, across from the terminal. In a 7 mph. current, securing the barges proved difficult; the captain of the Legacy finally pushed them into the woods and tied them off on some tree trunks before returning to the Oakley Terminal. About seven hours, later, though, the barges again broke loose, taking the tree trunks with them. The barges were later spotted on a sandbar at Mile 377. The Corps of Engineers considered sending a crew to secure them, but high water made the operation too risky.
At 10:40, with the Arkansas River rising to 42 feet, the barges floated free of the sand bar. At 11:18, Oklahoma highway patrol officers observed them at Mile 373 and estimated their speed at 8 to 9 mph. Within the hour, at 12:00, May 23, the barges struck the Webbers Falls Lock and Dam 16. Both barges were pinned against four of the dam gates, and the rushing river forced the upriver sides of the hopper barges downward, filling them with water until each sank.
Continued high water delayed their removal until August 10. Steel and concrete repairs to the dam were completed by September 10.
The NTSB determined that the probable cause of the barge breakaway and contact with the Webbers Falls Dam was the force of the river current acting on the moored vessels at the Grand River fleeting area. The current’s force was not distributed evenly among the wires, causing each wire to take the full strain in turn, resulting in consecutive failure.
The total cost of the incident, including barge recovery and repairs to the dam gates, was $4.7 million.
The full report is available at www.ntsb.gov/investigations/AccidentReports/Pages/MAB2028.aspx.