In the last two to three years, Hawai‘i’s
popular white-sand Kailua Beach has been dramatically affected
by shoreline erosion and beach loss. Though Kailua Beach usually
loses its shoreline at about a rate of one to three feet every
year, in these past couple of years, Kailua Beach erosion rates
have been as high as eight feet per year, which experts believe
to be one of the highest rates in the state.
I believe beach loss will have a significant impact on Hawai‘i’s
culture,” said Christopher Conger, a local shoreline specialist.
From native Hawaiians to transient tourists, most people who
are in Hawai‘i look to the ocean and the coastline for
activity and identity. The loss of beaches, coastal access, coastal
recreation, and cultural uses will have a profound impact on
Hawai‘i,” he said.
In the late 1990s, several studies showed that 25 percent of
O‘ahu’s sandy beaches had been lost or narrowed,
and 33 percent of Maui’s beaches had been degraded. That
trend has only continued,” Conger said.
Dolan Eversole, coastal geologist, says that Hawai‘i beaches
are showing some visible signs of erosion.
Typical signs of coastal erosion are narrowing of the beach,
eroded land with trees leaning or falling in, and failure of
shoreline structures as they are bypassed by the shoreline moving
forward,” he said.
According to Conger, one of the most visible signs of erosion
at Kailua Beach is the “sandgrabbers” or hollow-tile
bricks along the coastline that allow waves to wash sand through.
The majority of beaches in Hawai‘i are eroding with the
exception of a few stable or accreting bays,” Eversole
Though all Hawai‘i beaches are losing shoreline to erosion,
Eversole says localized short-term erosion appears to especially
accelerate on the North Shore of Maui and Kailua Beach.
In Kailua the erosion is centered near the Kaelepulu Stream mouth
and extends to either side of the stream,” Eversole said. “Ironically
the rest of the bay in Kailua is accreting.”
We can expect that erosion will be most susceptible on the southern
end,” said geologist Dr. Floyd McCoy. “Kailua is
a big beach, some parts erode and others build out.”
Although a definite cause for erosion and beach loss remains
elusive, experts believe that global warming and a subsequent
rise of sea level could be a factor.
Erosion is usually the result of wave energy environment, sediment
supply, and sea level,” Conger said. “Hawai‘i
has many eroding beaches, and some experts predict that erosion
will accelerate with rising sea levels.”
This increase in sea level, Eversole says, causes the shoreline
to migrate landward causing coastal erosion.
As global temperatures rise, land-locked ice melts,” Conger
said. “This water is new mass for the oceans and raises
sea level. An equally important issue is the increased temperature
of the oceans. Currently, thermal expansion is considered responsible
for up to half the modern sea level rise.”
While sea level may contribute to the noticeably worsening erosion,
Conger says that each location is different and therefore each
area eroding may have different factors that contribute to the
As Kailua Beach’s southern shoreline shows significant
erosion, there is concern from experts that erosion will continue
to progress up the beach. Conger says there is a fear that Kailua
will mimic Lanikai, which has lost most of its sandy shore to
Coastal erosion is like the cancer of coastal hazards. You don’t
really notice anything extreme until it’s too late,” Conger
Though coastal erosion may only be noticed far too late, coastal
experts are still working together with both the government and
private agencies to conserve and protect Hawai‘i’s
The first priority we are working towards is to not build so
close to the shoreline to begin with,” said Eversole. “This
would make a big difference in new developments and is something
within the power of local landowners.”
McCoy, who currently is helping to educate the public on the
importance of not building along the shoreline, says it is crucial
to give space for our beaches to grow.
There must be a wide coast for our beaches,” he said. “The
beach is where ocean meets the land, and if the ocean rises on
the land, new beaches will form. Unfortunately, where the new
beaches will form, is where houses and roads that never should
have never been put there will be.”
In the past, attempts have been made to slow or stop erosion
by building seawalls in front of these properties. But according
to Conger, while these seawalls were built to prevent erosion,
they have also sped beach loss along Kailua’s southern
Eversole states, the Department of Land and Natural Resources
and UH are working to identify “legacy” beaches that
have some chance of being preserved in the future where development
would be restricted near the shoreline.
Conger says that a beach management plan is currently being drafted
for Kailua Beach. This plan he says, is being created by private
consultants, but funded and overseen by the UH Sea Grant College
and the DLNR.
This will hopefully be the first step in proactively managing
the coastal resources as an integrated, spatial unit,” said
Conger. “Healthy coasts with intelligent development strategies
are also safe coasts for coastal communities,” he added.
As experts and government agencies work to preserve our beaches,
they have found that while beach restoration is a fast fix, it
is costly and only viable in certain areas.
Erosion cycles are natural phenomena,” said Conger. “You
can minimize their impacts or stop their progress if you are
willing to spend the time, energy, and money.”
Retreat is the long-term solution if we want to retain sandy
beaches,” said Eversole. “We are a long ways from
implementing this, but I see it as the only way we will be able
to protect our sandy beaches for our grandkids.”
I would expect, and this is my personal opinion, that the erosion
will continue to spread to the north and we will see beach narrowing
and long-term erosion into the coastal dune and coastal plain,” Conger
said Though erosion is a natural process that can never be completely
reduced, Eversole said it can be adapted to by retreating from
I don’t see any way to prevent erosion, but we do have
the ability to adjust to erosion by not developing the shoreline,
not allowing the trapping of sand behind shoreline structures,” said
Conger expects that there will be a handful of healthy beaches
where sediment supply is able to outpace long-term sea level
rise. He also believes there will be a number of protected beaches
identified as worth saving by agencies or private individuals. “But
I also expect that by 2100 Hawai‘i will have few beaches
left, as private property rights continue to outweigh resource
protection capacity,” Conger said.
In 10 years, Eversole says the condition of Kailua Beach will
all depend on if the current erosion cycle continues, stops,
or is mitigated by placing more sand in the system.
I feel our only hope of having sandy beaches in the next 50 years
is to identify important legacy beaches where we retreat from
the coast and ensure a natural sandy system is preserved,” said