how much water does the river parana contain

RickJ

I could not find an average volume IN the river, but did find an average discharge. Britannica says
"The volume of the lower Paraná River is dependent on the amount of water that it receives from the Paraguay River, which provides about 25 percent of the total; the Paraná's annual average discharge is 610,700 cubic feet per second (17,293 cubic metres per second)."

By volume it's the 2nd largest river in the world.