I spoke to one of the local, he said those wood debris you see on the beach are from Tsunami in Japan.
This is a famous water falls on island. If you could remember a show in the 70's Fantasy Island, this water falls it was on the show introduction.
I forgot to take picture on the warning signs in this area. If I could remember, it said something like DO NOT CROSS THE RAILS, OR ATTEMPTED TO CLIMB DOWN THE WATER FALLS. PEOPLE HAVE DIE HERE, AND FATAL INJURED.
To be honest, I did plan to climb down to the bottom of the water falls. To make sure, I have asked to one of the local boy just came up from the bottom of the water falls. He's nice enough offering his helps to take me down to the bottom to take picture, but he said the trail is very slippery, and it's very hard to get back up on the trail. If I get hurt, I need to figure out the way to get out without the authority helps. Otherwise, I will go to jail, after I got my treatment in the hospital.
You don't know how disappointed I'm not to get down to the bottom of the water falls. May be one day I will get this picture for you.
It's only easy way to get down if there no rain in the area for a week. Yeah right! you are talking about the wettest place on earth.