don't drink the holy water
Overview: Waimea Valley, on Oahu's north shore, features a tropical botanical garden, ruins of ancient Hawaiian structures, and a swimming hole at the base of its main attraction: Waimea Falls. Bring bug repellent!
History: Waimea Valley, or "Valley Of The Priests", has an extensive history. The valley was under the rule of Hawaiian high priests for many centuries, and two temples were constructed there. Numerous archeological sites, mostly unexcavated, bare witness to a historically large population. Waimea Valley was the scene of some of the earliest encounters (and conflicts) with European sailors. In more recent times, Waimea Valley has transitioned from theme park, to adventure park, to its present status as a botanical garden run by the Audubon Society.
Hike: From the visitor's center complex, several intertwining routes lead up the lush canyon, the main route being a closed asphalt road. The plant displays along the route are arranged according to their geographic occurrence, with plants from tropical areas around the world. Early on, one of the many side trails will take you to the ruins of some agricultural structures along the south slope of the canyon. Enormous koa trees keep the hike well shaded. The road crosses perennial Kamananui Stream several times.
This road hike reaches its end at an overlook of 40 foot high Waimea Falls, and its large natural pool, three quarters of a mile from the visitor's center. Brown cliffs of basalt form a box around the falls, whose flow varies greatly depending on rainfall and season. This popular swimming hole is open to swimming, lifeguard permitting. Enjoy the cool water, but avoid getting it in your mouth. Apparently, leptospirosis bacteria is a problem in Oahu's streams.
If you had not noticed the Hale O Lono temple ruins near the visitor's center, be sure to see them on the way out.
Check out the Triplogs.