Koʻolau Ditch

For more than a century the Koʻolau Ditch has been carrying up to 450 million gallons of water a day through 75 miles of flumes and tunnels from Maui’s rainy interior to the dry central plains. You can get a close-up look by stopping at the small pull-off just before the bridge that comes up immediately after the 8-mile marker. Just 30ft above the road you’ll see water flowing through a hand-hewn, stone-block section of the ditch before tunneling into the mountain.