Kailua mangrove removal

Kailua Mangrove Removal

Beginning Fall 2026

Hui o Ko’olaupoko is honored to enter into this partnership with DOFAW and bring the wetland and bird habitat restoration techniques we have learned at He’eia State Park back to our organization's home town. This will be a very visible restoration site for all who utilize the waterways of Kailua and we look forward to engaging the community directly with the project, through hands-on, small group experiences." -Kristen Kane HOK Project Director

Volunteer

Mangrove Research

Mangrove FAQs

kawainui: a brief history

PROJECT OVERVIEW
The Kawainui-Hamakua Marsh complex is the largest freshwater wetland in Hawaii and was designated a RAMSAR wetland of international importance in 2005. The adjacent town of Kailua is protected from annual flooding of Kawainui Marsh by a 6,850 ft earthen levee, originally constructed in 1966. The levee protects more than 2,000 residential structures and associated infrastructure in the Coconut Grove neighborhood of Kailua and is maintained by the Division of Forestry and Wildlife (DOFAW). Over the years, vegetation accumulation within Kawainui Marsh created a dense mat that affected the hydraulics of the marsh causing the levee to be overtopped during a January 1988 storm. As a result, the levee height was raised, and a concrete floodwall was installed on top of the levee in 1997. However, the issue of vegetation accumulation remains a critical threat to both flood storage capacity and wildlife habitat in Kawainui.

Both the Kawainui levee itself, and the two canals that drain toward the ocean, and Kaelepulu Pond (hereafter Kailua waterways) are threatened by encroaching invasive Red Mangrove (Rhizophora mangle) and other invasive plants that impede drainage and thus increase the risk of flooding into adjacent neighborhoods. In 2003-2004, mangrove was removed from Hamakua Marsh to create the current 23-acre wetland state wildlife sanctuary. In 2016-2019, eight (8) acres of invasive mangrove was removed from Kailua waterways adjacent to Kawainui and Hamakua. Smaller areas of mangrove still exist in Kailua waterways and threaten both drainage during flood events and the maintenance of previous mangrove removal efforts.

Phase 1: volunteer based efforts will focus on removal of small mangrove and seed pods from the portion of Kawainui stream that runs makai of the levee from Kawainui Neighborhood Park (Kaha Garden) to the Hamakua street bridge. This work is in partnership with DLNR, DOFAW.

Phase 2: A tree removal contractor will focus on removal of large mangrove from the portion of Kawainui stream that runs makai of the levee from Kawainui Neighborhood Park (Kaha Garden) to the Hamakua street bridge. This work is in partnership with DLNR, DOFAW.

Eradicating mangrove from Kailua waterways is a tractable goal that will have long-term benefits to the watershed since the area is unlikely to be recolonized quickly due to the distance from source populations in other ahupua'a.

The primary objective of the Kailua Mangrove Removal Project is to restore ecological landscapes that have been degraded by the invasive Red mangrove (rhizophora mangle). A major project goal is the restoration of critical foraging and nesting habitats for four endangered Hawaiian waterbird species, as mangroves rapidly colonize the open mudflats these birds depend on. From a hydrological perspective, this project aims to improve water quality and stream health by restoring natural flow and tidal mixing, which prevents the buildup of leaf litter that can lead to anoxic conditions. Additionally, clearing mangroves helps mitigate the risk of flash floods by removing blockages that trap sediment at stream mouths. Finally, these initiatives seek to reset benthic ecosystem functions, shifting the environment from a bacteria-dominated state back to one where diverse native macrofauna can effectively process carbon and nutrients.

Hui o Koʻolaupoko will aid DOFAW in the removal of ~5.2 acres of mature (i.e., seed-bearing) Red Mangrove trees that currently clog Kailua waterways and threaten areas previously cleared of mangrove. HOK will provide operational and planning support to implement community stewardship initiatives to facilitate project longevity. HOK will organize community groups, volunteers, local schools, and private, municipal government landowners to remove mangrove propagules, seedlings, and saplings by hand from 4.2 miles of the two drainage canals that comprise the Kailua waterways and patrol 116 acres of the entire Kailua waterway system for mangrove re-encroachment. HOK will also provide planning support to DOFAW in hiring contractors to remove mature mangroves. Post large mangrove removal, HOK will activate community stewards to rehabilitate cleared areas with native wetland plants along 1.2 riparian miles managed by DOFAW to prevent future encroachment of invasive species and create nesting habitat for endangered wetland birds.

"Thank you for teaching us about the native plants and invasive ones. I liked when we got to get dirty and dig a hole for the Uala or sweet potato."

-Isaiah,
Kainalu Elementary

"Thank you for teaching me about Kaha Garden and all the plants and the weeds that take over. I also took a Kukui nut to try and plant at home because I think it will interest my family."

-Crystal,
Kainalu Elementary

"Now I know many of the ways Hawaiians used our native plants instead of us going to a store or something to figure it out. Now I will use some of these strategies."

-Justice,
Kainalu Elementary

Kaha Garden Native Plant ID Cards
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Kaha Garden Description
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