I was heading out to the vicinity of the Nike HQ by my commute route from back when I worked there. I was surprised when I passed this park because I don't remember any water there. But then, that wasn't a thing for me back then.
Saturday, March 27, 2021
google map 
45.4837805, -122.7912138
45.4836182, -122.7908421
45.4822472, -122.7922277
45.4834027, -122.7938305
45.4841416, -122.7950527
BOUNDARY 45.4816220, -122.7972306
BOUNDARY 45.4858520, -122.7891746
This seems to be drainage on both sides of the freeway that comes and goes nowhere.
Saturday, July 17, 2021
Here we see the creek duck under Griffith Drive at the south end of this green space.