The picnicking facilities are wheelchair accessible The main hiking trail loop is not paved, have long steep climbs, stairs and would be impassable for nearly all wheelchairs. The portion of the loop along the riverside might be doable with a all terrain chair when things are dry but it becomes a slippery, muddy mess with a flooding potential when it rains. I have been there when it became a serious challenge for experienced hikers because of a weather change.
Only the flat part. Trails really aren't but if you have an all terrain wheel chair the river scene trail might be okay. Powder Valley in Kirkwood has beautiful paved trails.
Parts of it are more or less "wheel chair tolerable". Unfortunately its not a great place if you have mobility needs, but some places are doable.
The main park itself is open and flat with some paved roads. The trails are a different story. They vary in terrain, and some are quite hilly/rocky. I would not recommend attempting them in a wheelchair. Hope this helps!
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