Ko‘olau Mountains Watershed Partnership

History & Mission

The mission of the Ko‘olau Mountains Watershed Partnership is to foster landowner collaboration and perpetuate the water resources of O‘ahu by protecting and enhancing the forests of the Ko‘olau and its invaluable native ecosystems.

Since the formation of the partnership in 1999, our mission has been to maintain the health of the forested expanses of the Koʻolau range as a reliable source of high-quality water for Oʻahu’s people in perpetuity. These partners recognized the importance of these forest ecosystems for their ability to replenish the underground aquifers which provide the majority of the fresh water used on Oʻahu – approximately 133 billion gallons each year.

KMWP works to coordinate and perform critical forest management actions such as controlling the spread of invasive plants and animals across nearly 100,000 acres of partnership lands. The mitigation of threats to the integrity of our native forests is crucial to safeguard our precious freshwater resources into the future. KMWP employs a small number of full-time staff under the University of Hawaii Pacific Cooperative Studies Unit (PCSU), to manage all projects across the Ko’olau range. Though they come from a variety of backgrounds and experiences, they share an appreciation for our watersheds and are passionate about the role they play in helping to protect and conserve our native forests.

Ecosystem Highlights

The Ko‘olau Mountain forests supply groundwater for approximately 90% of the population on the Island of O‘ahu. As the main source of fresh water on the island, ground water recharge is the most valuable product produced by the Ko‘olau forests, providing 364 million gallons of water per day.

The preservation of the remaining native forests is critical to the protection of watersheds on O‘ahu, as their multi-layered canopies efficiently capture moisture from clouds and reduce the force of rain falling on the soil surface, allowing the water to gently infiltrate into the soil and ultimately reach underground aquifers. However, the native forests of the Ko‘olau Mountains are severely imperiled. Close to 50% of the primarily native forests have been lost and those that remain are threatened by invasive species and climate change. Invasive species alter the water capture and infiltration rates of native forests by reducing canopy complexity and destroying understory native plant communities.

In addition to harming watershed function, invasive plants and animals present an existential threat to rare native Hawaiian species. The Ko‘olau Mountains has one of the highest densities of rare species in the world. The area provides habitat for dozens of endangered species, many of which are endemic to the range and found nowhere else in the world.

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