NORTHBROOK — The Chicago River has a waterfall and lots of rapids, too.
Well, sort of.
Far from the river's main stem Downtown as it expands to three branches on the Northwest Side and suburban North Shore, the river has a few fast-moving parts where the water streams over rocks. The movement creates a form of small rapids, or what Friends of the Chicago River executive director Margaret Frisbie calls "riffles."
"There are several places in the forest preserves where there are riffles like that," said Frisbie, who noted that within Chicago, those riffles are in LaBagh Woods on the Northwest Side. "They add oxygen to the water, which helps aquatic life."
Some of the riffles, like the ones at Chicago's Eugene Field Park, are from man-made rock formations, while others are natural, Frisbie said. A few are the result of development along the river like in suburban Northbrook.