Upper Willamette System Fishing Report and Forecast Posted on August 25, 2022August 25, 2022 by Glenn Zinkus Green Peter Kokes. Detroit Lake Kokes. Middle Fork Willamette Trout and Steelhead. Explore The Upper Forks Of The Middle Willamette Alton Baker Canal: Alton Baker Canal was stocked with 900 legal size trout. As always,... This post is only available to Members. If you are a Member, please be sure to log in and remember to select the Remember Me option. If you want to become a member or find out more, take a look here.