A Clear Solution for Kulanihakoi
For years, we’ve been looking for a real solution to the flooding problems at Kulanihakoi—something practical, achievable, and grounded in how this land actually works. The answer is simpler than most people think. Raise the roadway just enough to let the water pass underneath. The Kulanihakoi Elevated Roadway concept does exactly that. It keeps traffic moving, protects nearby homes, and restores the natural flow of water from mauka to makai without introducing anything out of place for Kīhei.
Why This Area Floods So Easily
Kulanihakoi sits within one of the most flood-prone areas in all of South Maui, where inland drainage, coastal wetlands, and shoreline processes all converge. Water does not move through this area in a narrow channel. It spreads, slows, and moves across a wide landscape before reaching the ocean. That natural behavior is exactly what the current roadway interrupts, and it is why flooding here is not an occasional problem—it is a predictable one.
Roads Built Across Natural Flow
South Kihei Road was built across every gulch and drainage path in this region. Each crossing creates a choke point. The original engineering was never designed for the volume of water we now see, nor the debris that comes down during major storms. As a result, every heavy rain event follows the same pattern. Water reaches the road, slows, backs up, and begins to spread outward into neighborhoods and across the roadway itself.
When the Road Becomes the Problem
At Kulanihakoi, the roadway cuts directly across an active wetland and drainage system. Instead of allowing water to pass through, it traps it. That trapped water builds pressure, overtops the road, and pushes laterally into nearby properties. Vehicles stall, traffic stops, and emergency rescues become necessary. At the same time, debris and silt accumulate at these choke points, reducing drainage capacity and making each future storm worse than the last. This is not a failure of maintenance. It is a limitation of the design itself.
Elevating the Roadway Changes Everything
The Kulanihakoi Elevated Roadway removes that limitation. By lifting this section of roadway several feet, water is allowed to pass beneath it instead of being blocked. Flow is restored, pressure is reduced, and the system begins to function the way it should. The road remains in place and continues to serve traffic, but it no longer acts as a barrier within the landscape.
Built for the Future, Not the Past
This solution is not just about solving today’s flooding. It is about preparing for what is already coming. Climate experts consistently point to more intense storms, higher rainfall events, and increased coastal impacts across Maui. Kīhei will not only face greater runoff from mauka, but also increased pressure from the ocean during high wave events and coastal flooding. Infrastructure that barely works today will not hold up under those future conditions. This is the moment to build something that is designed for what’s ahead, not what we used to experience.
Open Span Is the Only Real Solution
Conventional culverts will not solve this problem. They clog. They restrict flow. They fail under debris load. At Kulanihakoi, the volume of water and debris moving through this system requires a fully open span. Water must be able to pass freely across the entire width of the gulch mouth without being forced through narrow openings. Based on the exposed natural width of this system, that span may need to extend 750 feet or more. This is not overbuilding—it is matching the scale of the natural system that already exists.
More Water Is Coming From Mauka
Runoff is not static. It is increasing. Upcountry development, new residential projects, and expanding impervious surfaces are already changing how water moves down toward South Maui. More pavement means less absorption and faster runoff. Those changes are already underway. That means more water, moving faster, arriving at the same choke points that are already failing today. Any solution that does not account for this increase will be outdated before it is even completed.
Protecting Critical Infrastructure
South Kihei Road is not just a roadway. It carries essential infrastructure beneath it, including water systems and other utilities that serve the community. When the road fails, it is not just a traffic issue. It becomes a broader infrastructure risk. Flooding, erosion, and repeated stress on this corridor threaten more than just vehicles—they threaten the systems people depend on every day. Elevating the roadway reduces that risk by stabilizing the environment around it instead of forcing water into it.
Working With Wetlands, Not Against Them
This area includes both inland and coastal wetlands, and those systems depend on movement. Water must be able to spread, settle, and reconnect with the ocean. When that movement is blocked, the entire system is disrupted. Elevating the roadway restores that connection. It allows the wetlands to function properly while reducing flood risk to surrounding areas. Protecting wetlands and improving drainage are not separate goals here—they are part of the same solution.
A Local Solution That Fits Kīhei
This is not a mainland-style overpass or a large elevated freeway. It is a raised roadway, following the same path that already exists, lifted just enough to solve a known problem. We already elevate roads when crossing gulches. This simply extends that same idea to an area where water spreads across a wider zone. It is familiar, it is achievable, and it fits the character of South Maui.
Let the Water Pass
At its core, this is a simple shift in thinking. Roads should not act like dams. They should allow water to move. The Kulanihakoi Elevated Roadway does exactly that by lifting the road, restoring flow, and reducing the risks that have become all too familiar in South Maui.
