You are in luck, I know a few things about that area, it's above the falls, so its open for the trout salmon steel n sturgies only until 2 pm each day. The flat is the mouth of the tualatin, good LM spawning spot, I also caught the biggest yellow perch ever there, thought it was a bass at first. To your right, in the Tualatin itself are some rocks I imagine are loaded with salad right now. Good for smallies and I even pulled 2 carp outta there. Over to the left is the boat launch and off to the left of that is a seasonally available rock point that you can fish for anything on the main river from there. I hear of large catfish too, though haven't found any myself. My favorites for bass there are topwater and spinnerbait type lures. I know coho play in the area in the fall but I think boats have much better success than bankies there. I lived nearby but since have moved, I've spent days fishing that park, enjoy it and try all the different little ecosystems out there and I hope you find some monsters. Try tossing a worm out, you never know what you'll find on the other end!