The water running out of the mountains along the North Cascade Highway brings a lot of sediment with it. The result of this is that the rivers and lakes that form along the route of the pass have a distinct green color to them. The Skagit River in Newhalem has a clear green color to it. However, the more dramatic demonstration of this coloration is visible at Diablo Lake. This lake that is formed behind Diablo Dam has a very green appearance. It looks like it must have been created artificially but it is just the result of carrying the minerals down from the mountains above. Of course, a polarizer does a good job of highlighting the color when the reflections are removed.