Any traffic delays that occur on the highways over the coming holiday weekend could pale in comparison to the one in store for river travelers starting Monday.

The Army Corps of Engineers will close the main chambers of two Ohio River locks for 19 days of maintenance at 12:01 a.m. that day and warns that the closure "will create extremely long delays for all river users, especially recreational boaters."

The affected locks are at Emsworth, 6.2 miles downstream from the Point, and Dashields, 13.3 miles downstream. The closures are expected to last until 11 p.m. July 24.

The much smaller auxiliary chambers will remain open at both locks, but moving commercial barges through them is extraordinarily time-consuming, and commercial traffic will have priority over recreational vessels, according to Corps spokesman Jeff Hawk.

Because of the size of the chambers -- 56 feet wide and 360 feet long compared with 110 feet by 600 feet for the main chambers -- commercial tows must go through one barge at a time.

One tow of 15 jumbo barges could take up to 15 hours to get through Emsworth and Dashields, compared to two hours when the main chambers are open.

Delays for recreational boaters will range from a few hours to more than 10 hours, the Corps said. It recommends that boaters avoid the affected area.

The Corps will have a command center staffed around the clock at the locks in case of emergencies.

The work is being done now because both locks have been assessed at high risk for breakdown and because a maintenance fleet from Huntington, W.Va., was available to assist in the repairs, cutting the downtime from 38 days to 19. Also, coal traffic, which accounts for three-quarters of the traffic, will be at an ebb.

At Emsworth, the Corps will repair the valves that lower water levels in the lock. The main chamber must be drained for the work. At Dashields, the corps will repair three 110- to 125-ton gates that contain water when vessels are moving through.

Recreational boaters are urged to contact Dashields at 724-457-8430, Emsworth at 412-766-6213 or use marine radio channel 13 before arriving at either lock.