sentences:  Below the ridge down into the ravine through which the water falls can be seen the vertical dikes of basalt that cut through the horizontal Koloa lava flows.The name "Ōpaekaa" means rolling shrimp, "opae" being Hawaiian for "shrimp," and "kaa" for "rolling".The name dates back to days when the native freshwater shrimp "Atyoida bisulcata" were plentiful in the stream and were seen rolling and tumbling down the falls and into the churning waters at the fall's base.