Tide station locations on map?

[Waterfish]

I want to pencil in the tide stations on my Evergreen Cruising Atlas of the Columbia and Willamette Rivers. Most tide stations are obvious (Kelly Point, Vancouver, etc) and I can find and highlight them on my charts. But there are some that I cannot find, like "Knappa Slough". Is there a web site link or map that shows the location of all of the tide stations?