Updated May 2025
Maui’s coral ecosystems are some of the most vibrant and resilient in Hawai‘i — but they’re also facing immense pressure. Years of sediment runoff from historic agriculture continue to disrupt the delicate relationship between land and sea. That’s why, in Olowalu, we’re taking bold, community-led action.
At the Coral Reef Alliance (CORAL), we’re working alongside local partners and cultural stewards to tackle the biggest threat to West Maui’s reefs: land-based pollution. Building on successful work in Wahikuli, our latest efforts focus on reforesting degraded riparian zones in the Olowalu ahupua‘a — a powerful ridge-to-reef strategy rooted in both science and traditional ecological knowledge.
Why Olowalu?
Spanning 812 acres, Olowalu Reef is a designated “Hope Spot” by Dr. Sylvia Earle and plays a critical role in seeding nearby reefs around Maui, Lana‘i, Moloka‘i, and Kaho‘olawe. With its unusually high coral cover, resilience to bleaching events, and importance to local fisheries, it’s one of the most essential marine habitats in the Hawaiian Islands.
Just uphill, though, the landscape tells another story. Degraded watersheds and invasive stream habitats toward the coastline during storms — smothering corals, fueling algal overgrowth, and unraveling the balance of reef ecosystems.
Restoring the Ahupua‘a
Over the next three years, we’re taking a full ahupua‘a approach — restoring the land to protect the ocean. That means thinning out the tree canopy to allow sunlight through, reinforcing streambanks with ground covers, installing native vegetation like pili grass to slow water flow, and creating conditions for long-term soil stability.
On the reef side, we’re tracking ecosystem health with temperature sensors and sediment traps — all to better understand how changes upstream affect the marine environment.
But this work is about more than just monitoring equipment and native planting. We’re supporting community partners to strengthen restoration and long-term data collection while cultural practices remain at every level. For example, lo’i kalo (wetland taro) patches along the riparian zone allow sediment to be filtered before water is returned to the stream while allowing cultural practices to thrive.
By pairing indigenous wisdom with science-based strategies, we’re collectively creating a conservation model that’s truly rooted in place — and built to endure.
What We’re Learning
In our first phase, we’ve already made big strides: preparing key sites, clearing debris, starting native seedlings, and nurturing the first wave of native plants. Baseline monitoring stations now track conditions both on land and beneath the waves, giving us a clear starting point to measure progress.
What’s next? Riparian restoration along the entire Olowalu stream, coral surveys, community outreach for marine management planning, and sharing our findings across the state so others can adapt and build on what we’re learning in Olowalu.
Why It Matters
Economically, coral reefs contribute over $800 million to Hawai‘i’s economy each year through tourism, and over $900 million in shoreline protection value.
Beyond dollars, every streambank we reforest helps keep sediment off the reef. Every native plant we restore filters water for future generations. Every partner we work with is equipped to carry this work forward long after the project ends.
These aren’t just environmental wins — they’re community wins. Cleaner water means safer fishing. Stronger reefs mean food security. A healthy ahupua‘a means honoring cultural traditions and protecting what makes Maui, Maui.
In short, this project extends beyond coral reefs. It fosters connection between people and place, ridge and reef, past and future.
Our monitoring efforts are already generating valuable data that will inform future watershed management across Hawai‘i. And through hands-on restoration, we’re not just restoring land — we’re restoring community capacity, cultural practices, and long-term resilience.
