The operation was part of "Desert Scimitar," a military exercise involving 1,900 Marines and about 500 vehicles.
During Desert Scimitar, members of the 1st Marine Division, mostly officers and their staffs, are trekking 170 miles of desert highways from Yuma to Twentynine Palms.
"It's known as TEWT — Tactical Exercise Without Troops. A division usually has more than 18,000 Marines, but mostly commanders and staff are participating in this exercise," said Maj. Hal Angus.
Along the way, the division will fight simulated battles, although no shots will be fired and no enemy forces will be present.
The purpose of the exercise is to train the division command in directing battlefield actions.
"This is a unique opportunity for the 1st Marine Division to experience a challenging and realistic training exercise. This is vital for our national security. If this were real, we would be under fire," said Capt. Patricia Restrepo.
Crossing the Colorado River is part of the training.
"The bridge crossing is a significant event, especially doing it on a river the magnitude of the Colorado with its current. In the 17 years I've been in the military, I've never seen it done like this. We need to do it more often," Angus said.
The use of floating bridges, or pontoon bridges, by the military dates back to the Civil War. The bridges were crude then, made up of planks fastened to boats, spanning riverbank to riverbank.
Today's pontoon bridges are usually made of steel, bolted together and anchored to the river bottom.
The bridge near Palo Verde is temporary and will be removed once the 1st Marine Division has crossed the river and continued its trek toward Twentynine Palms.