https://www.oregonhikers.org/field_guide/Dry_Creek_Hike
In the description it says
As you would guess, a bit of Dry Creek was dry last week. I didn't actually make an attempt to measure how much of it was dry (because I figured it was normal to be dry) but it was below and above the horse bypass section. I would guess about 2000 feet.And no, the creek does not seem to ever get dry, even in the depths of a summer drought.