Last Saturday, the Star-Advertiser’s lead headline was one word — “Wow!” — commenting on 700-foot high-rises that the Hawaii Community Development Authority is proposing for Kakaako. That headline should have been, “Ouch!”
Within the lifetimes of current young adults and children, rising seas will erode our beaches and flood low-lying streets and roads around the island. By the latter part of this century, projections have portions of Waikiki, Moiliili, Ala Moana and Kakaako standing in sea water at high tide. Key thoroughfares in urban Honolulu and around Oahu will be below sea level.
But sea level rise is just the start of our problems.
A research paper by University of Hawaii professors Kolja Rotzoll and Charles “Chip” Fletcher in the scientific journal, Nature Climate Change, discusses another hidden and potentially more massive problem: groundwater inundation (Page 3: http://www.soest.hawaii.edu/coasts/publications/Rotzoll%20Fletcher%20NCC%202012.pdf).
The coastal plains of each island, created by lava flows and ancient coral reefs and then covered by layers of sediment, are a massive array of porous geology. In low-lying areas, the water table (the sub-surface level below which the ground is completely saturated with water) lies just below the surface.
There, fresh water, which has seeped down, floats atop salt water which has worked its way in from the ocean. This salt water, which is generally at the same height as sea level, rises and falls with the tides. As the sea level rises in the future, it will cause this salt water to also rise permanently, pushing the fresh water above it through the ground. Once the water pushes above the surface, it will have nowhere to go, and will just sit there. Rain will add to the problem.
Groundwater flooding could put far greater parts of Waikiki, Moiliili and Ala Moana permanently under water, along with much of Kakaako, where the 700-foot high-rises are planned. Ouch!
Low-lying areas in Leeward, and in numerous other places around Oahu, also will be flooded. This groundwater inundation will begin to be a problem before mid-century and will continue to grow and spread as the seas rise, for centuries to come. Being inland groundwater, pushed up through the land, it cannot be stopped by dikes.
In light of all this, does it make sense to build skyscrapers in the Kakaako floodlands? Should we really construct more buildings in Waikiki? Is it logical to build a rail line from Kapolei to Ala Moana, if much of the route, and all of the Ala Moana area, lie deep in the future flood zone? Are we set to spend billions on rail, sewers, water mains and roads to be redirected?
The first concern in the old Oahu General Plan was the need to control population growth. Given our projected future, is it moral to build homes for the unsuspecting? Is it wise to keep expanding tourism?
Worldwide, costs to accommodate sea rise will raise prices on everything, making imports, including food, far more expensive. We will need to grow much more of our own food. Isn’t it suicidal to sacrifice today’s highest-producing farmlands for unnecessary housing projects?
Where are the county plans to guide all of this? 
In 2012, the state Legislature passed Act 286, which directed that all county general plans and county development plans must engage in focused research to produce models of future climate changes and their impacts, and must include in the plans steps to address those impacts. That is not happening.
Instead, those who profit directly from development have enough friends in the right places that the city is moving to get as much anticipated development through the approval gate as possible, before the populace wakes up.
It’s time to stop all county plan approvals, take the plans back to the drawing boards and spend the necessary time to study the ramifications of sea level rise and groundwater inundation for Oahu, and to devise steps to address them, as state law requires.
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On vacation: “On Politics” columnist Richard Borreca is on vacation.
