Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Lake Mead:

"

At lower water levels, a high-water mark or "bathtub ring" is visible in photos that show the shoreline of Lake Mead. The bathtub ring is white because of the leaching of minerals on previously submerged surfaces.[4]