Hawai'i Watershed Partnerships (HAWP) — Cooperative Forest Protection Against Invasive Species

The Hawai'i Association of Watershed Partnerships (HAWP), established in 2003, coordinates ten island-based watershed partnerships across five Hawaiian islands, engaging over 100 public agencies, private landowners and NGOs.

The partnerships aim to protect more than 2.6 million acres of native forested watershed land - Hawai'i's primary freshwater recharge zone - which collapses when invasive plants or feral ungulates remove forest cover.

The principal tools are permanent exclusion fencing against feral pigs, goats and deer, followed by intensive invasive plant removal and native seedling outplanting. The State pays for the public-works dimension: DLNR allocates approximately US$2.5 million annually to partnerships, with total private and federal funds leveraged reaching US$12 million since 2006.

Cumulative results through 2024: 300,000 acres managed for ungulates and invasive species, 40+ miles of protective fencing completed, 100,000 native and endangered plants outplanted, and 7,000 community volunteers engaged. Three Mountain Alliance (Maui) protects 3 critically endangered forest birds and 25 endangered plant species across 230,000 acres. East Moloka'i Watershed Partnership completed 11.4 miles of fencing protecting 104 miles of perennial streams. A UHERO peer-reviewed benefit-cost analysis for the Kaua'i Watershed Alliance found that existing fences save 593 gallons of groundwater recharge per dollar invested over a 50-year horizon - equivalent to protecting 21.4 billion gallons of fresh water - with comparable analyses finding approximately 400 gal/$ on Hawai'i Island and 321 gal/$ on Maui.

The cooperative model relies on voluntary participation by private landowners and public agencies rather than legally binding PES contracts. Carbon and biodiversity co-benefits are not independently certified, and governance depends on sustained state appropriations with no formal mechanism if ownership changes.