nprofile1qy2hwumn8ghj7un9d3shjtnyd968gmewwp6kyqpq6mznujsc4alkznqaqw7vtslucfvudjluwvkc2rg4aggy0k3ungeqnj6jyx (nprofile…6jyx) There are paved, low-grade paths in the river valley close to the Kinsmen Sports Centre (south side of Walterdale bridge), which has a convenient parking lot. It isn't really "nature" area there, but you're still near the water.
Beyond that, I don't have any personal recommendations, but you got me looking to see what info is available.
The City of Edmonton has PDF/print maps of trails that show info on slope (if it's steeper than a "well-built wheelchair ramp") & paving. In addition to the River Valley, the central one shows the Mill Creek ravine near you (including paved shared-use paths with only a few significant slopes noted).
I also found these guides from the Edmonton Nature Centres Foundation, with a search tool to filter for "easy" walks or even wheelchair accessible.
Here's one for Mill Creek South.