People have been farming with rerouted fresh water in the North Kohala district on the Big Island for centuries. Talk with Bill Wong, and he'll tell you about some of the region's ancient loi, or taro patches, that are still intact and date back more than 600 years.
Wong owns Kohala Ditch Adventures, which has been offering guided tours of the century-old waterway for about a year.
"Hawaiians engineered systems where water would come out of the stream and go into terraces, water each taro patch, then terrace back into the stream," he said. "So no water was wasted. It was directed into the loi, did its job, then returned to its source."
According to Wong, King Kamehameha, a Kohala native and the first monarch to unite the Hawaiian Islands, did a little farming and irrigation engineering in the region, as well.
"He made his own tunnel system through the streams up there," Wong said. "Hawaiians would make fire and burn the rocks. Then they'd pour water on them to cool it, and when the rocks cracked, they chipped away at it to make tunnels to transport water down into the loi."
According to Wong, Kohala was covered with taro, a Hawaiian root vegetable, long before the district's once-booming sugar industry took hold during the late 1800s and plans for a much more ambitious irrigation project were drawn up. Known today as simply the Kohala Ditch, the 23-mile canal has transported spring water from deep in the Kohala Mountains at Honokane for more than a century, boring through hillsides and snaking along the valleys' cliffs down into the little town of Hawi on the Big Island's northern coast.
Six hundred Japanese laborers completed work on the ditch in 1906, digging the entire canal and its 57 tunnels with picks, shovels and dynamite in just over 18 months. Although Kohala's last sugar mill closed in the 1970s, the ditch remains a vital source of water for the community's farmers and ranchers today and is an excellent place for visitors to get a feel for the region's heritage and natural beauty.
"It opens up a whole new realm for visitors who don't necessarily realize what goes on beyond the beach," said Stacey Canedy, an account manager for Panache Destination Management.
Canedy has been working for 10 years with high-end incentive groups traveling to the Islands, helping them better understand the state's range of activity options.
"The fact that you're actually floating through history and going inside these incredible tunnels is a huge wow factor" with her groups, she said.
Lasting a total of 2.5 hours, the guided tour begins with a 45-minute off-road trek onboard a six-wheeled, 12-passenger Pinzgauer military transport up into the Kohala Mountains, followed by a short hike to one of the ditch's 60-foot-tall redwood flumes, or irrigation bridges. Before climbing into an 18-foot, inflatable kayak, guests walk over the flume for a closer look at a photogenic waterfall and a peak into one of the ditch's hand-dug tunnels.
Time on the water lasts a little over an hour, and although clients are advised to wear swimsuits, you don't get soaked: Wet rear ends and feet are generally the worst of it. The 2.5-mile float glides at a sleepy pace through dense rain forest, 10 surprisingly dark tunnels -- the longest is 1,800 feet -- and more than seven flumes, accompanied throughout by sugar plantation and ditch history; Hawaiian legends and culture; and even a few regional ghost stories recounted by friendly guides with all kinds of experience in the area.
"The majority of our guides are fourth-, fifth- and sixth-generation natives from the community here," said Wong, who grew up in Kohala and comes from Chinese and Hawaiian ancestry. "They are all part native Hawaiian, so they all have their family and cultural values tied to this area."
Wong has been offering ATV tours in Kohala for nearly 15 years but took over the ditch adventure concession only recently, reopening the activity for the first time since a magnitude 6.7 earthquake damaged the canal in 2006.
"A landslide wiped out the first flume ... it was like somebody just turned a valve off," Wong said. "It took two years and $6 million in private funding to repair the damage and get the system back up."
While the ditch was dry, Wong said, state officials spent months inspecting the entire canal's structural integrity.
"Amazingly, none of the tunnels suffered any damage," he said. "I guess it's like the old saying: They don't build them like they used to."
Commissionable to agents, the Kohala Ditch adventure is $129 for adults and $65 for children under 12. Visit www.kohaladitchadventures.com