I know it's hard to make out what you're looking at in these pictures. The "reeds" (or whatever they are) are very tall. Taller than They are at least as tall as phragmites, which is already about twice or more as tall as cattails. These pictures were taken from the side of a small esker, and look down onto this wetland. These plants looked basically like grass, but much taller than any grass I've ever seen. I'd guess they were 10-12 feet tall (up to around 4 meters). They are only growing where it's really wet. Basically, it looks like this stuff grows in the same conditions you'd expect to find cattails in.
This is definitely fresh water. It's miles from the coast and about 300 feet elevation. There is no salt or brackish water anywhere around here.
The reason I don't think this is phragmites is because there are no tassles at the top anywhere. Not a single one was visible in this whole stand. I see plenty of phragmites around this area daily, and the tassles are present at this time and quite obvious.