When on vacation in Hawaii don’t be afraid to drink the water. There are lots of vacation destinations that come with built-in cautions about water quality. Hawaii definitely is not one of them.
Oahu in particular is blessed with water that ranks with the best quality in the world. Part of the reason is the island’s unique water cycle, which is difficult to find in places such as, say, Kansas City.
Hawaii’s almost-omnipresent trade winds carry with them moisture that has evaporated from ocean water warmed by the sun. The winds blow across the ocean and reach Oahu from the northeast, then are deflected upwards as they hit the steep cliffs of the Koolau Mountains. The rising moisture cools as it reaches the mountaintops then forms clouds, condenses and falls as rain. If Oahu didn’t have both mountain ranges and flat plains, the island wouldn’t be able to capture the moist air needed to support the living things that exist now. (The island of Niihau, on the other hand, gets very little rainfall because it doesn’t have much in the way of elevated slopes.)
In a year, about two billion gallons of rain fall on Oahu every day. About a third of that replenishes the island’s aquifer (the layer of rock, sand and gravel ground water flows through), another third nurtures the island’s vegetation and the rest runs off into the ocean.
For the drinking water you’ll enjoy while you’re here, the Honolulu Board of Water Supply uses four shafts, 12 tunnels and 84 well stations around the island to draw water from the ground. Dike Tunnels are drilled through a mountain to its dike rock compartment where freshwater is drawn out before it reaches the aquifer. Inclined shafts descend hundreds of feet to the top of the aquifer, skimming its upper layer to extract fresh water. Deep wells are located over the aquifer and supply most of the island’s water.
On the surface, the water enters a complex and unique water transmission system, which transports water from pumping stations to customers. Pumping stations pump water from the shafts, tunnels and wells into the transmission system. Sometimes, booster stations are used to push water over long distances and to higher elevations. The purpose of pumping and booster stations is to deliver fresh water to the reservoirs, which store water for future use. Finally, when water is needed, it’s fed back into water mains for delivery to hotels and resorts, homes and businesses. More than 2,000 miles of transmission mains are utilized to convey fresh water from the pumping stations to the reservoirs, and to your hotel room and the restaurants you visit.
Drink up. It’s good stuff.
Posted by: Jamie Winpenny on Mar 10, 2009