Because right now, it's entirely too low. So low that historic items and ginormous catfish are surfacing.

Assignment #207 in the 365 Things to Do in Memphis is to head to the Riverwalk and see the river levels sign.

The sign is big - big enough to see from the water - and it lets sailors know which direction the river is moving. For example, in the picture above, the river is 6 feet below sea level and falling.

You can find it about halfway down the Riverwalk, which is a paved sidewalk runs along the bluff overlooking the Mississippi from about Union Ave. to South Bluffs.