Plant suggestion for a ditch side in Denver

We have an irrigation ditch crossing our property. Within certain limits, we can landscape it. The area is a natural floodplain with a high water table.

What kinds of useful, beautify, edible, and wild life attracting plants can we introduce?

We are not replacing or disturbing a native ecosystem; this is a constructed ditch. There is currently some middle aged cottonwoods, which have got a lot of deadwood and snags in them, and some Siberian Elm trees. The understory is a tangle of sticks, fallen logs, trash, and a collapsed fence, with a few weeds, grass, and poison hemlock. We are clearing it out, because even though it might provide habitat for a few critters, it is a horrible eyesore, and I think we can make it better. We are leaving some of the bigger cottonwoods, but there will be plenty of sun for an understory and replacement trees. The line of trees faces South, and the remaining trees and water should produce a warm microclimate.

asparagus, buffalo berry, grapes, raspberries

I'd go native plants - I'm not sure if it's native to that area, but try looking up: choke cherry (or some other wild cherry varieties), elderberry, there may be a native blackberry, mulefat?, sasktoon service berry, salmon berry, deer grass, lupins, Indian Rice Grass, Chia, sages, coyote bush, tiger lilly, wild strawberries, California mugwort, native stinging nettle, gourds/squash?. Good luck!