1. Melt butter in a large saucepan over medium-high heat. Add onion, celery, and garlic; cook 5 minutes or until translucent.
2. Add flour, and cook 5 minutes, stirring constantly. Stir in garlic powder and next 5 ingredients; cook 1 minute.
3. Stir in chicken stock and next 3 ingredients. Bring to a simmer; cook 20 minutes or until potatoes are cooked through. Add salmon; cook 1 minute or just until done.