The same geology that gives Hawaii its staggering natural beauty is also the natural force that gives these islands the supply of fresh water that makes life sustainable for humans and the endemic (and invasive) species that have made it home throughout history. The Honolulu Board of Water Supply offers several free, educational tours that take visitors into, literally, the hydrologic cycle of Hawaii. The BWS is committed to educating the public about O’ahu’s water.
The Waihe’e Tunnel Tour, deep in Waihe’e Valley on O’ahu’s windward side, is a truly compelling trek through the rainforest to Waihe’e Tunnel. The tunnel is man-made, 1500 feet into the the basalt lava rock foundation of the Ko’olau Mountains. The tour is a damp one, as water flows from above like rainfall at the tunnel’s terminus, as fresh and pure as water on Earth can be. Once inside the tunnel, the tour is also a dark one. The tunnel entrance becomes just a pinpoint of light the farther the tour gets, and when it splits off to the bulkhead, there is simply no light other than that of the flashlights brought it.
The tour explains the island’s water cycle, and its abundance and limits. The water that drips from the tunnel ceiling has been percolating through rock for 25 years. None of Oahu’s fresh water comes from surface water like rivers or lakes, but rather from the groundwater supply. Oahu’s water is filtered naturally for decades through volcanic rock before becoming part of the groundwater supply.
The Nu’uanu Watershed Tour also provides the story of O’ahu’s water cycle and the Nu’uanu Reservoir, and features stunning panoramic views of the historic valley (it is the site where King Kamehameha I sealed his victory on O’ahu). The tour provides insight into the rich history and mythology of the Nu’uanu Valley, and into the importance of water conservation.
The Fred Ohrt Water Museum Tour takes place at the Kalihi Pumping Station, just a mile or so from Downtown Honolulu. The tour features “the Old Man of Kalihi,” the original steam pump constructed in 1899. With interesting displays and the constant hum of working water pumps (now electric, of course), the tour is a kind of immersive one, as visitors are at the heart of a working municipal water system.
The Halawa Xeriscape Garden Tour takes place at the Halawa Pumping Station, located in Halawa Valley, one of the most significant cultural sites in all of Hawaii. The tour a variety of native and introduced plant species that are notable for their water-conserving properties. The garden is also open to the public on Wednesdays and Saturdays. The Halawa Shaft, dug deep into the valley floor, is currently closed for renovations, but when completed, tours will resume. Contact the BWS for shaft tour status.
All of the tours offered by the Board of Water Supply are given by reservation only, and may be limited. Contact the BWS at (808) 748-5041 or email firstname.lastname@example.org for information and reservations.