Track the height of the Chicago River (and other rivers)

How high is the river near you? The U.S. Geological Survey has real-time water data! You can look up the past 31 days of water activity. Pictured above is a graph for the Chicago River at Columbus Drive (that's right in downtown Chicago). Look! It changes, by as much as a foot in one month!

Does the moon effect the height of rivers? Or is that only with lakes and oceans?