Here is a better picture of the grass. It has a strong root base that is clumped. for the little that we had, it had lots of roots.
here is a picture from May of last year in the same area before we dug the pond. I think the large clumps of grass are the same.
Here is a picture of the same area in mid summer. I think the tall grass is the same, but I don't know.
I hope that helps with identifying.
