In two locations this year I've had rivers in the shot come out looking unnaturally blue. It's a beautiful, deep blue, but looks "too perfect" to be real, like too much saturation. Once was in Cook State Park on the Kenai Peninsula in Alaska, and again recently at Snake River Overlook in Grand Teton National Park. The conditions were similar, though: an hour to two after sunrise with the sun almost directly behind me under clear sky. Is this a common optical effect I should be aware of? Is there a shooting fix? I wasn't using a polarizer. Once was with a Canon S70 and the other with a Canon Rebel XT, both RAW, both using around 28mm "equivalent" focal length. Unfortunately I don't have a place to post them on the web quite yet for you to see them.