On Earth, cataracts represent regions where a river’s gradient increases enough to create so much turbulence, that air gets incorporated into the water body forming a bubbly current sometimes called “whitewater”. This image covers a location that may have acted as a cataract in the Kasei valley region.
This observation samples the bedrock lithologies and gives us a measure of the post-flood erosion and modification history for the floor of Kasei Valles. At high resolution, we can also look for boulders. [More at link]