Opaekaa Falls is a waterfall located on the Wailua River in Wailua River State Park on the eastern side of the Hawaiian island of Kauai. It is a 151–foot waterfall that flows over basalt from volcanic eruptions millions of years ago. The name "Opaekaa" means rolling shrimp, "ʻopae" being Hawaiian for "shrimp," and "kaʻa" 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. Visually, this is a spectacular waterfall and is one of the island's few waterfalls that can be seen from the road (Highway 580). Just a very short stroll from the highway parking lot offers an excellent overview of the Falls. The tops of the Makeleha Mountains can be seen in the background. Opaekaa Falls flows year round. As far as I know, it is not possible to hike down to where the water falls into a pool (at least not via any state-sanctioned trails).
The Wailua River (as seen above) and the Wailua River Valley (as seen below) can be viewed by crossing the road at the pedestrian crossing sign which is just a short stroll further from the Falls lookout.