Ala Wai Watershed Collaboration

The Ala Wai Watershed Collaboration began work on an 18-month feasibility study of eight partner-led projects in early 2021 with the support of grant funding from the Department of Interior. Collaboration partners' eight projects address various opportunities for improved sustainability and resiliency of the watershed from mauka to makai.

This study includes a rigorous technical analysis of projects assessed through the newly developed Mālama Implementation Tool to support an iterative stakeholder driven process. The outcome of this feasibility study highlights alignment of the projects with both the  Aloha+ Challenge  Goals and Hawaiian host culture and island values, as well as next steps to support the implementation of these initiatives. 

Eight Partner-Led Projects

• Ala Wai Canal Flushing System and Golf Course Detention System
• Albizia Prevention and Removal
• Floating Debris Catchment Technology
• Green Infrastructure Projects
• Local Food Production
• Miconia Eradication
• Ungulate Fencing
• Watershed Environmental Sensor and Data Platform

This project proposes alterations to the Ala Wai Golf Course to support flood management of the Ala Wai Canal, directly adjacent to the golf course property. This includes proposals to divert the Mānoa-Palolo stream through the golf course and provide a series of treatment wetlands and sedimentation ponds that will serve as treatment, flood storage, and water features for the golf course. The plan also conceptualizes a flushing system to add flow and re-circulation in the canal in low-flow conditions.

This project supports the  Ko‘olau Mountains Watershed Partnership (KMWP) ’s ongoing albizia control program. KMWP leads the removal of albizia on O‘ahu over 20,000 acres of affected land. KMWP additionally leads community outreach efforts, working to educate and encourage individuals to remove young albizia trees from their own neighborhoods, private properties, and stream banks.

This project involves constructing debris catchment nets at the Mānoa and Makiki streams, preventing debris from reaching the Ala Wai Canal. The project seeks to support the current trash collection boom located at the mouth of the canal at the entrance to the Ala Wai Boat Harbor, which is managed by the  Department of Land and Natural Resources .

 3Rwater, Inc.  developed the Follow The Drop app, an island-wide tool to assist property owners in assessing their stormwater runoff on their property and identify options for green stormwater infrastructure retrofits. 3Rwater partnered with the Honolulu Board of Watershed Supply to establish an incentive program including potential fee credits and rebates with the establishment of a stormwater utility. The app conducted a 2021 pilot project for properties within the ‘Āina Haina watershed and seeks to expand outreach on the app into the Ala Wai watershed. In addition to facilitating outreach on the app, this project supports gathering data from stormwater projects to track progress on Hawai‘i’s statewide sustainability goals, outlined in the Aloha+ Challenge. This project also includes an educational aspect as 3Rwater has developed a Follow The Drop curriculum to teach students about green workforce opportunities and how to assess green stormwater infrastructure improvements on their campuses.

This project is currently still finalizing its scope, but aims to support a range of ʻāina-based activities. This could include support for lo‘i pond restoration and expansion, that is already well underway by a number of organizations within the watershed. Additional thoughts include restoration of coconut trees and other fruit bearing vegetative cover in existing and new residential and urban developments.

This project supports the ongoing Miconia calvescens control program led by the  Oʻahu Invasive Species Committee (OISC)  in the Ala Wai Watershed, a region with one of the highest population densities of miconia on Oʻahu. This invasive plant greatly enhances flooding, landslides, and nutrient rich top-soil runoff to aquatic and marine environments due to its shallow root systems and leaf morphology. Since 2001, OISC has been able to reduce the density of mature miconia trees by 96%. In 2019, OISC detected and controlled only 5 mature trees over 9,207 acres. In a scenario without control efforts, there would be an unmanageable population of about 2,835 mature trees and 2,810 acres infested.

This project supports the  DLNR Division of Forestry and Wildlife (DOFAW)  ungulate control efforts. Feral pig activities alter the forest ecosystem by destroying native vegetation and facilitating the spread of invasive weeds. Invasive weeds outcompete native vegetation and may lead to increased runoff and erosion, leading to further flooding and pollution in lower urban areas. The project aims to cover the Kōnāhuanui and Wa’ahila areas of the southern Ko’olau Range, protecting 703 acres with the installation of 24,413 feet of fencing.

This project works to support the other seven projects subject to the feasibility study by establishing monitoring priorities for each project and facilitating data collection needs. The data collection is supported by the  SMART Ala Wai  project, a student-led data collection team at the University of Hawai‘i which focuses on comprehensive environmental sensing research and community education, as well as  Hohonu, Inc. , a local public-private startup focused on operational environmental sensing data services.