Living in the area I can confirm that there is no disc golf course in the area. It’s a big park but between the communal gardens and pond, private golf course and the power line park there is no room to put one in.
I have been thinking for a while that the area on the other side of West Union (Emerald Estate Park, Bethany Meadows Park, Ben Graf Park and Springville Meadows Park) would make a great area for a course. The park is not overflowing with joggers or walkers. It has some very nice elevation with a nice mix of open fairways, trees and a creek with bushes. There is plenty of room for 9 or even 18 hole course with some long fairways. The only downside is there is not a lot of parking areas. With very little work the area could be another nice course for the west side of Portland. There is a need for something a little more challenging than Orchard and Greenway and it would relieve some of the current crowding at those two courses. THPRD has been putting a lot of money in the parks in this part of town and it would be nice addition, especially if they could link it up with the PCC athletic complex.
http://maps.google.com/maps?ll=45.562518,-122.84246&z=15&t=h&hl=en