Flood Impact Mitigation Project
Building on our completed work supported by a National Science Foundation / University of Hawai‘i grant, we are continuing this important effort through a North Shore Watershed Flood Mitigation grant. This work is about more than removing invasive trees—it’s about investing in the safety, resilience, and well-being of our community. By targeting problematic species like Albizia along residential properties in Wainiha Valley, we’re reducing the impacts of flooding, property damage, and environmental harm. At the same time, we’re putting meaningful work into the hands of local arborists and tradespeople—supporting those who care for the land while improving it for their neighbors. It’s a project that brings lasting value to our residents, strengthening both the environment and the local economy, and ensuring these areas are better prepared for the next flood event.
The Story of Albizia
Originally brought to Hawaii in 1917 to combat soil erosion and promote reforestation, Albizia was valued for its rapid growth—up to 15 feet per year—and its ability to quickly stabilize slopes. Unfortunately, what was once seen as a solution has become an ecological challenge. Albizia has become an invasive species, outcompeting native plants and disrupting local ecosystems.
Growing up to 150 feet tall with an expansive canopy that spreads 20–50 feet wide, Albizia trees overshadow native vegetation. Despite their impressive speed, their weak wood often leads to limb failure or entire trees toppling, especially during storms or floods. Their water-loving roots along riverbanks accelerate growth and heighten flood risks.
Wainiha Valley
In Wainiha, our team conducts thorough research and assessments to identify trees most likely to topple during flood events. Targeted removal of these high-risk trees aims to prevent blockages, protect roads, and safeguard property. Our ongoing work involves close collaboration with landowners, community members, and experts to prioritize and implement these critical actions.
Looking Ahead
Through community engagement, scientific assessment, and strategic action, the Hanalei Initiative is working to reduce flood hazards and promote ecological renewal. Removing dangerous Albizia trees is a vital step toward a safer, healthier Kauai—one where the natural landscape thrives in harmony with resilient communities.
Mahalo to Our
Partners
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National Science Foundation
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University of Hawaiʻi