Main Hawaiian Islands Reefscape


Hawaiʻi is a critical site for global coral reef conservation with some of the highest marine endemism recorded anywhere on Earth and about 85 percent of the United States’ coral reefs. Hawaiʻi’s reefs face significant global and local threats including climate change, overfishing and sediment and nutrient pollution caused by sewage and stormwater runoff.

CORAL has more than a decade of experience working in the Main Hawaiian Islands on coral reef conservation. CORAL’s work in Hawaiʻi focuses on our Clean Water for Reefs Initiative, with an emphasis on preventing land-based sources of pollution from entering streams and groundwater which eventually lead to the ocean.

We work in two priority sites, which together form the beginnings of a Hawaiian Adaptive Reefscape — a network of healthy reefs that can adapt to climate change because it is diverse, connected and large.


On Hawai‘i Island, we work closely with the Puakō community to address wastewater pollution. Because of the high groundwater table and very porous rock found along the coast, inadequately treated wastewater from cesspools and septic tanks does not get filtered by soil. Instead, this wastewater flows directly into the groundwater and then ends up in the ocean – causing serious damage to corals, negatively affecting marine life and posing risks to human health. In Puakō, CORAL works alongside a formal Advisory Committee which includes researchers, industry experts and community representatives. Based on a Preliminary Engineering Report, the Advisory Committee recommended that the community build an onsite wastewater treatment facility. We are working with community members to turn this vision into a reality, and are developing a science-based monitoring plan (which includes a citizen science component) to measure the ecological and socioeconomic benefits of improved wastewater management.

In West Maui, our work focuses on restoring natural filtration processes within watersheds to prevent land-based water pollution from degrading reefs. High levels of sediment runoff can reduce corals’ access to sunlight by smothering them, negatively impacting reef health. High nutrients cause algal blooms which can overtake coral and promote coral disease. We take a “ridge to reef” approach to restore the natural function of an ahupua‘a (watershed) to filter stormwater and absorb nutrients, sediments and other chemicals. At the shoreline, we provide guidance to shoreline property owners, the tourism industry and Maui County on how to implement reef-friendly landscaping design which naturally filter stormwater before it reaches the ocean. Further inland (midslope), our work focuses on stream restoration to reduce the amount of sediment and nutrients flowing into the ocean. CORAL is working with farmers, Hawaiian communities, local nonprofits, private businesses and the government to pilot stream restoration techniques that combine modern technology with native vegetation and traditional agricultural practices. To increase filtration processes in and around stream beds, we are re-establishing native vegetation and taking lessons from Hawaiʻi’s long history of traditional agricultural practices. Traditional wetland taro patches (loʻi kalo) absorb nutrients and trap sediment and are deeply embedded in Hawaiian culture. We are also planting deep-rooted vetiver grasses, which trap and stabilize sediments and enable native vegetation to thrive.


  • 2006: CORAL begins working in Hawai‘i with an initial focus on sustainable marine recreation
  • 2009: CORAL and partners train over 350 tourism professionals in sustainable marine recreation and install reef etiquette signs in more than 50 highly visible locations across Hawaiʻi
  • 2009: CORAL helps establish the Kahekili Herbivore Fisheries Management Area (KHFMA) in Kaʻanapali, West Maui; herbivorous fish are vital to coral reef ecosystems as they feed on algae and prevent it from overtaking coral reefs
  • 2010: CORAL expands its work to address water pollution because of the significant threat it poses to coral reefs and the lack of attention surrounding the issue
  • 2014: CORAL launches the Clean Water for Reefs Puakō project to develop a solution to replace cesspools in Puakō with improved wastewater treatment infrastructure
  • 2015: CORAL begins working with the Maui County Department of Public Works to integrate reef-friendly landscaping design into county ordinances and permitting processes
  • 2016: CORAL motivates 17 shoreline property owners on Maui Island to invest over $19 million in reef-friendly landscaping, resulting in 277 acres of land under improved management filtering over 35 million gallons of stormwater per year
  • 2016: CORAL forms an expert knowledge sharing group in West Maui to design and implement a stream restoration plan to reduce the amount of sediment and nutrient pollution reaching coral reefs


Danielle Swenson
Engagement Manager
Hawaiʻi Island
Erica Perez
Program Manager
Hawaiʻi Island
Wesley Crile
Program Manager
Maui Island
Alicia Srinivas
Associate Programs Manager
Oakland, California (HQ)
Jos Hill
Associate Programs Director
Oakland, California (HQ)



Map of CORAL's Field Sites in the Main Hawaiian Islands

CORAL’s Field Sites in the Main Hawaiian Islands

Additional Resources