Deep into the pristine, native forest reserve above Ka‘ū Coffee Mill’s lands, parts of a water supply system have lain dry for decades, unused, their origins tracing back to early sugar plantation days. In recent years, the crew of Ka‘ū Coffee Mill renovated several USGS ash bed tunnels in this area. Carved through solid rock and layers of volcanic ash, these tunnels meander underground for lengths of 2,000 feet and more. Descending from elevations as high as 3,500 feet and including a 13-million gallon black-sand and native-stone reservoir, Keaīwa, this system is now being restored to provide water to the farm lands and farmers of Ka‘ū, serve the Mill, and double as a hydroelectric resource. A 12-inch pipeline has replaced old leaking flumes, while materials have been recycled and reused whenever possible for history to connect with the future and agriculture to continue throughout. Once the system is fully operational, Ka‘ū Coffee Mill may be the first coffee mill in the nation to be fully green-powered. Any extra energy to be generated through the hydroelectric plant will be sold to the island’s utility grid.