Placeholder text and link: Announcement to Plan. Link to Executive Summary.
Existing and ongoing planning efforts can be leveraged to support One Water Solutions across O’ahu.
A Resilience Roadmap
By the end of 2026, the One Water Honolulu Plan will support implementation of the City and County of Honolulu’s Climate Ready O’ahu strategy, to prepare and safeguard people, ʻāina, and infrastructure, by providing a holistic water management plan and a 30-year list of multi-benefit projects to build resilience in our island’s infrastructure and natural systems.
The One Water Plan is a collaborative roadmap that focuses on how to implement the resilience strategy, recognizing that most climate impacts involve water—too much or too little of it.
Dive into O’ahu’s Water story
Guided by a Collaboration Framework
A key component of One Water Honolulu is the Collaboration Framework, which provides a structured approach for action-oriented solutions and joint decision-making.
It recognizes that climate change impacts can only be mitigated by collaboratively working together within City and state agencies, large landowners, developers, organizations, consultants, and the community.
Collaboration is so essential to achieving climate resilience that it was institutionalized in City Ordinance 20-47, which created the One Water Panel of eight City Departments that will extend progress across future administrations and ensure continuity in purpose and long-term results.
There is a wide range of potential stakeholders to consider when building resilience across our infrastructure and for our communities.
Developing One Water Projects
Through the Collaboration Framework, the One Water Panel and its partners will coordinate infrastructure development, including identifying priority projects and developing project scopes and budgets.
The panel will also maintain a multi-year infrastructure investment strategy for the identified projects through the City and County’s annual Capital Improvement Program budget, implement associated policies and regulations, and pursue partnerships between agencies, developers, and the community.
One Water Honolulu Planning Timeline
Plan completion expected September 2026.
Our Vision
Collaborating for a thriving and climate resilient O’ahu.
Our Mission
Champion cost-effective and climate-resilient infrastructure services and natural systems for the people, culture, and sustainability of O’ahu through integration and innovation in planning, implementation, and maintenance.
Climate Change Adaptation Framework
Where climate risks are greatest and where investment is needed most.
The Plan screens the island’s water infrastructure for exposure to climate hazards — from flooding and sea level rise to tsunamis — to pinpoint where risks are greatest and where investment is needed most.
500,000+ assets evaluated → Top 0.5% screened as most vulnerable → 92 geographic hotspots identified → 14 Priority Hotspots selected
- Climate Risk Screening: Evaluate more than 500,000 water, wastewater, and stormwater infrastructure assets using GIS mapping, identifying the top 0.5% most vulnerable water infrastructure.
- Known Areas of Concern: Combine technical analysis with existing City and community knowledge—previous planning efforts, stakeholder engagement, existing project ideas, adaptive capacity, and input from the One Water Panel and Leadership Group—to identify local issues and community concerns.
- Hotspot Identification: Group at-risk infrastructure and known concerns into geographic areas where climate adaptation or risk intervention may be most urgent, identifying 92 geographic hotspots for additional evaluation and prioritization.
- Priority Hotspots: Identify 14 Priority Hotspots across Oʻahu through the Climate Hotspot Identification Process, providing a foundation for future project identification and prioritization.
Funding Strategy
How the City funds, finances, and sustains resilience investments over time.
The Plan relies on a coordinated, diversified approach to funding — one that supports planning, capital investment, and long-term operations, because no single source can meet the scale of investment the vision requires.
- Diversified Portfolio: Combine City appropriations, utility revenues, grants, low-interest financing, bonds, resilience programs, and future dedicated funding mechanisms to support priorities that lack sustainable funding today, such as flood resilience, watershed restoration, sea level rise, and wildfire adaptation.
- Dual-Track Approach: Advance projects with the funding tools available now while building the institutional and financial capacity to sustain resilience investments for decades to come.
- Ratepayer Affordability: Balance infrastructure needs with affordability for residents, businesses, and utility customers by maximizing external funding, pursuing cost-sharing, leveraging low-interest financing, and sequencing investments over time.
- Near-Term Priorities: Focus early efforts on the studies and plans that lay the groundwork for larger investments and compete strongly for outside funding: watershed studies, adaptation plans, drainage master planning, water reuse studies, monitoring, and community resilience planning.
- Budget Integration: Weave One Water Honolulu priorities into the City’s annual budgeting, CIP updates, grant cycles, and long-range planning, with recurring touchpoints that keep them visible and competitive.
Dive Deeper
Purpose, Governance and Collaboration
Climate, Water Systems, Data and Regional Context
Risk Screening, hotspot identification, and priority location goals
- Appendix D: Climate Adaptation Framework
- Appendix E: Climate Vulnerability Maps
- Appendix F: Hotspot Profiles
Project development, prioritization, policies, and actions
Implementation, triggers, CIP alignment, and funding