State Department of Health Continues to Support Watershed Restoration on Kaho‘olawe

The Kahoʻolawe Island Reserve Commission has begun a three-year watershed restoration project in Kamōhio Watershed on Kahoʻolawe, made possible through grant funding from the Hawaiʻi State Department of Health, Surface Water Protection Branch, and the US Environmental Protection Agency.

The Restoration of Kamōhio Watershed Phase I project will take place from 2025 through 2028 and focuses on reducing sedimentation and improving water quality in Kamōhio Bay and surrounding nearshore waters.

The 45-acre project site is located in the middle reaches of Kamōhio Watershed, one of 24 watersheds on Kahoʻolawe.

The phase one of the project site is located on the southeast slope of Kaho’olawe between 1,100ft and 1,200ft in elevation and contains both Tier One-surface cleared and Tier Two- 4 foot removal depth of UXO clearance areas.

Restoration activities include the installation of erosion control best management practices such as wattles and check dams, the establishment of irrigated planting corridors, invasive species management, and the outplanting of approximately 22,500 drought-tolerant native Hawaiian trees, shrubs, and grasses.

Together, these efforts are projected to reduce sediment loads by an estimated 22.5 tons per year while increasing native vegetation cover and improving soil infiltration.

Kamōhio Watershed was the first to receive approval on its watershed-based plan by the new Surface Water Protection Branch. Although Kahoʻolawe is not listed as impaired under the State’s water quality assessments, sedimentation from decades of land degradation remains the primary nonpoint source pollutant affecting Kamōhio Bay. Restoration of native dryland ecosystems has been shown to significantly reduce stormwater runoff, sediment transport, and nearshore turbidity.

“This project represents an important step forward in restoring Kamōhio Watershed and protecting downstream marine resources,” said KIRC Restoration Manager Paul Higashino. “By combining proven erosion control techniques with native plant restoration and long-term monitoring, we can reduce sediment runoff while rebuilding a resilient, self-sustaining ecosystem.”

The project will also incorporate extensive monitoring, including rainfall and stream stage measurements, soil erosion pin transects, vegetation plots, soil infiltration testing, and drone-based imagery to document changes in vegetation health and landscape stability over time. Volunteers will play a critical role in implementation, working alongside KIRC staff during scheduled access trips to Kahoʻolawe.

KIRC Executive Director Michael Nāhoʻopiʻi added, “Support from the Department of Health, the US Environmental Protection Agency, and the many volunteers who contribute their time and energy is essential to fulfilling our mission. These partnerships allow us to protect and restore Kahoʻolawe’s cultural, historical, and environmental resources for future generations.”

This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreements C9-96978720-0, C9-96978721-0, C9-96978722-0, C9-96978723-0, and C9-96978724-0 to the Hawaiʻi State Department of Health, Surface Water Protection Branch.

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