The Manawaiopuna Falls, also called Rainbow Falls, is found in Hilo, Hawaii, on the Wailuku River State Park. A rainbow can almost always be seen in the morning as the mists rise from the falls.
The Hawaiian people have a legend that surrounds the falls. There was a god named Hina that lived behind the water of the falls, and every so often she would be bothered by a large lizard named Mo’o Kuna. The lizard found it his only duty in life to disrupt the river and falls by sending torrents of water and rocks over the falls. During a terrible storm, the lizard was able to move a huge boulder to block the falls, causing the water to flow into Hina’s cave. She called to her son, Maui, a demi-god to help. Maui paddled a canoe up the Wailuku River to the boulder blocking the fall, and in one blow split the rock to release the water. Maui, in retribution, called on Pele to send lave down the river to drive Mo’o Kuna from his hiding spot in the deep upper stream potholes called the boiling pots.
The lava made these potholes boils, thus killing the lizard. These potholes are actually places where the water eroded into an old lava flow that was under the river bed. These potholes are likely connected underneath, making them very violent during harsh storms, so they actually appear to be boiling. The entire Hawaiian Islands were actually formed from recurring lava flow, so many river beds are made from these old flows. At one point, the Wailuku River had eroded the riverbed into two old lava flows, but an eruption filled them back in over 10,000 years ago.
Tourists can see the remnants of the old bed, as the rocks and boulders that are buried in the new lave flow poke out. The Rainbow falls is on the small side when it comes to the world’s waterfalls, on 80 feet tall, but it is the rich history and stunning morning rainbows that make it a wonderful waterfall. This area is also home to many tropical plants, like Bamboo.
There is actually another Rainbow Falls on the island of Kauai that stands 360 feet tall, this was features in the beginning of the movie Jurassic Park.