Koʻolau Mountains Watershed Partnership — Corporate Water Replenishment Fence Project (Hawaiʻi, USA)

Founded in 1999, the Koʻolau Mountains Watershed Partnership (KMWP) unites 17 landowning partners and 10 associate partners — including the State of Hawaiʻi, Kamehameha Schools, the U.S. Army and the Honolulu Board of Water Supply — to manage more than 100,000 acres of public and private land across Oʻahu's Koʻolau range, a system that supplies roughly 90% of the island's potable water through aquifer recharge.

In April 2017, DLNR, KMWP and The Coca-Cola Company announced a water-replenishment project centred on a $200,000 Coca-Cola Foundation grant, matched by $100,000 from the Honolulu Board of Water Supply and $100,000 in state watershed capital-improvement funds. The financing built a 6.6-mile fence enclosing 1,400 acres of priority forest — 1,000 acres of Kamehameha Schools land and 400 acres of the state's ʻEwa Forest Reserve — to exclude feral pigs, goats and invasive plants that degrade the native canopy needed for the Waiawa aquifer system to recharge. That system underlies the Pearl Harbor aquifer, which delivers more than 364 million gallons of water a day.

The project sits within Hawaiʻi's broader state goal of protecting 30% of its priority watersheds by 2030. KMWP's model — corporate, utility and state co-funding routed through a standing multi-landowner partnership — has since been replicated by other watershed partnerships coordinated under the Hawaiʻi Association of Watershed Partnerships.

No independently published before/after data on invasive-species density or aquifer recharge specific to this fence exists; KMWP staff describe a "significant positive impact" over ten years in qualitative terms rather than with monitored metrics, and the fence is one component of a much larger, longer-running partnership rather than a standalone, separately evaluated intervention.

Read the full analysis: https://dlnr.hawaii.gov/blog/2017/04/11/nr17-061/