Kohala supports a very complex hydrological cycle. In the early part of the 20th century, this was exploited by building surface irrigational channels designed to capture water at the higher elevations and distribute it to the then-extensive sugarcane industry. In 1905, after 18 months and the loss of 17 lives, the Kohala Ditch, a vast network of flumes and ditches, measuring in length, was completed. It has since come into use by ranches, farms, and homes. A portion of the ditch became a tourist attraction until it was damaged by the 2006 Kiholo Bay earthquake, centered just southwest of the mountain. The Hawaii County Department of Water Supply relies on streams from Kohala to supply water to the population of the island. With increasing demand, the original surface channels have been supplemented by deep wells designed to channel groundwater for domestic use. In 2003 the Kohala Watershed Partnership was formed, a voluntary group of private land owners and state managers, designed to help manage the Kohala watershed and to protect it from threats, most especially invasive species.