Willamette, McKenzie & Santiam Rivers Fishing Report for Aug 5th Posted on August 4, 2016 by Michael Teague Welp, it’s summer all right. With the water temperatures at Willamette Falls holding steady at 77 degrees since August 1st, one can only wonder what temps the lower river have... To access this post, you must purchase Oregon Memberships – Steelhead or Oregon Memberships – Chinook.