State of the Beach/State Reports/HI/Shoreline Structures

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Hawaii state law allows shoreline structures to improve aesthetic and engineering solutions to erosion that do not block beach access or interfere with existing recreational activities in areas not designated as Special Management Areas or Shoreline Setback Areas. Special Management Areas or Shoreline Setback Areas have stricter policies regarding development of new structures.

Under Hawaii's Coastal Zone Management Law, HRS Chapter 205A-2, it is the policy of the State of Hawaii to discourage all shoreline hardening (also known as shoreline armoring) that may affect access to, or the configuration of, the island beaches. Chapter 205A-2 also has the following provisions:

(B) Prohibit construction of private erosion-protection structures seaward of the shoreline, except when they result in improved aesthetic and engineering solutions to erosion at the sites and do not interfere with existing recreational and waterline activities; and
(C) Minimize the construction of public erosion-protection structures seaward of the shoreline. Before 1970, shoreline protection devices could be constructed without a permit. In 1970, Hawaii instituted a shoreline setback policy that required permits for any construction seaward of the setback line. This Shoreline Setback Area, the area between the shoreline and the shoreline setback line, was noted above. Currently, most shoreline setback lines are set at 40 feet from the shoreline, although in some places the Shoreline Setback boundaries extend further inland. The counties have the authority to set deeper setbacks. Structures or portions of a structure are not permitted in the shoreline setback area without a variance. Variances may be granted for specified structures or activities including private facilities or improvements. No variance shall be granted unless appropriate conditions are imposed.

Hawaii is trying to develop a Comprehensive Coastal Policy. Ideally, such a policy would establish common goals among concerned agencies with regard to beach conservation. These goals should link and re-enforce planning and decision-making between federal, state, and county authorities, where the land meets the sea. Regarding shoreline hardening, the shoreline policy development document states:

"It has been well documented that seawalls and shoreline structures on a chronically eroding shoreline can lead to beach loss or narrowing by restricting the natural movement of the shoreline landward. With a hard structure in place the beach may not maintain the original width as it retreats landward and instead narrows. The Department attempts to mitigate negative impacts to the coastal system from shore protection structures by encouraging alternative erosion control measures in place of constructing seawall and revetments."

An existing "loophole" in the regulations regarding seawalls was enlarged with the passage of House Bill 117 HD2 in 2011. Under HB 117 HD2, private property owners along the shoreline are given preferential treatment over the publicly owned beach under state law. Hawaii Revised Statute 205A-2 already allows coastal property owners to build erosion-control structures such as seawalls under cases of "hardship," when the ocean reaches within 20 feet of their structure. Both HB 117 HD2 and an existing HRS 205A-2 loophole elevate the interests of coastal landowners above those of the general public.

Honolulu Ordinances include:

Shoreline Setbacks (Revised Ordinances of Honolulu Chapter 23):

The policy states that structures are prohibited within the shoreline area. Shoreline area is the area between the designated shoreline, usually the upper reaches of the wash of the waves on the highest high tide (vegetation line), and shoreline setback line, which usually is 40 feet. Structures include groins, walls (likely seawalls), revetments and anything constructed or erected with a fixed location at or under the ground.

Structures and activities are prohibited within the shoreline area, with the following exceptions:

(1) Minor structures and activities permitted under rules adopted by the department which do not affect beach processes or artificially fix the shoreline and do not interfere with public access, public views or open space along the shoreline. If, due to beach erosion or other cause, the director determines that a minor structure permitted under this section may affect beach processes or public access or has become located seaward of the shoreline, the director or other governmental agency having jurisdiction may order its removal;
(2) Minor structures and activities necessary for or ancillary to continuation, but not expansion, of agriculture or aquaculture in the shoreline area on June 16, 1989.

Special Management Area (Revised Ordinances of Honolulu Chapter 25):

No development or structure shall be constructed within the special management area without first obtaining a special management area use permit, a minor permit or being exempted pursuant to the provisions of this chapter.
The policy set forth in the shoreline setback and special management area ordinances will be waived if a disaster has been declared.

County websites may also provide additional information on permitting or rules.[1]

As an alternative to hardened structures, the State DLNR is working on guidelines for truly temporary biodegradable erosion control sandbags. These bags and blankets are intended to serve as temporary emergency erosion control and are composed of 100% coconut fiber (Coir). Initial trials have gone very well with inexpensive material costs, easy installation and biodegradable nature. These appear to be the new standard for emergency erosion control in Hawaii. Typical Coir structures may last 6 months to 2 years depending on the environment. One trial project using a Coir blanket and bags as steps was installed in 2008 at Off the Wall (North shore of Oahu) and appears to be holding up reasonably well even under heavy, photographer foot traffic and digging in to the bank.



The Department of Land and Natural Resources’s Hawaii Coastal Erosion Management Plan states that studies conducted at the University of Hawaii show that hardening the shoreline of Oahu where there is chronic coastal erosion causes beach narrowing and beach loss. Researchers have found that on Oahu 10.7 miles of beach has been narrowed by shoreline hardening and 6.4 miles has been lost. This is approximately 24% of the 71.6 miles of originally sandy shoreline on Oahu.

A controversial groin/beach fill project for the Waikiki area was reported in Honolulu Magazine:

"Kyo-ya Hotels and Resorts, which owns the Sheraton Waikiki, is hoping to erect three 160-foot, T-shaped groins in front of the hotel, trapping sand and rebuilding a stretch of beach that is currently all but nonexistent. It’s a concept supported by the Hawaii Hotel and Lodging Association as well as the Hawaii Tourism Authority, and in May 2008 the state Legislature got on board as well, setting aside $1 million in its 2008-2009 budget for restoration projects on resort beaches.

But opponents are already vowing to block the project. George Downing, longtime waterman and spokesperson for the Save Our Surf organization, says the plan amounts to “armoring” the coastline, and will ruin nearby surfing breaks and exacerbate the area’s erosion problems. “What they should do is remove the groin that’s currently in front of the Royal Hawaiian, and let the beach form itself naturally,” he says. See comments from Downing and Scott Werny of Surfrider Foundation's Oahu Chapter on the enabling legislation.

Sam Lemmo, administrator for the Coastal Lands Division at the state Department of Land and Natural Resources, says he’s withholding judgment on this specific project until he sees an environmental impact study, but says that well-engineered beach reclamation projects can be beneficial. “Reclaiming sand from offshore [with groins] should be better for the ecology and the surfing than simply pouring new sand on the beach, because you’re restoring the reef’s 3-D dimensions by pulling the sand off of it,” he says."

A seawall issue arose along the Kahala beachfront in early 2015. A wealthy South Korean businessman who bought two Kahala beachfront properties was required to tear out an illegal seawall that was encroaching on the public beach. But the city has since given Lee Kun-hee, the billionaire chairman of South Korea’s Samsung Group, permission to erect a new wall just mauka of the state’s certified shoreline, which scientists say will exacerbate beach erosion. Critics say the city approval also signals a destructive trend when it comes to allowing seawalls and other structures that harden the shoreline, effectively expanding a loophole in the law that allows property owners to claim hardship when arguing for a protective wall. More on this.


The shoreline structures were mapped by the County of Maui Planning Department in summer 2003. Approximately 15.6 miles of the 56 miles of coastline surveyed were classified as hardened, including seawalls, revetments, grouted revetments, sandbags, and groins. This means that 13% of Maui’s 120 miles of shoreline is armored. The areas not included in the survey, such as the east side of Maui are mostly coastal cliffs and include relatively few beaches. The beaches in Hana, on the east side of Maui may only have a small amount of armoring and are not included in this estimation. The position and length of the structures were recorded using a handheld GIS. In addition to the classification, several other assessments were made at each shoreline structure. The questions were geared at assessing the impacts of the structure on local beach processes, public lateral access, and public visual access. For example, at each site it was noted if coastal erosion was occurring on the sides of the structure and the width of the beach in front of the structure was estimated. This information is available from Maui’s Department of Planning in the form of a CD. The CD contains an ArcView project that includes the position and descriptions for the surveyed structures.

In the densely developed Honokowai area on Maui, 3500 feet of shoreline armoring exists over a 6000-foot stretch. Island-wide, a total of approximately 6 km of beach have been lost completely.[2]

Recent research has documented that affects attributed to shoreline armoring have resulted in approximately 25% of Oahu's and 30% of Maui's sandy shoreline being either significantly narrowed or lost.

According to a December 2015 article in Lahaina News:

West Siders are protective of the vital two-lane portion of Honoapiilani Highway from Lahaina to the Pali Tunnel. The once idyllic scenic coastal corridor is being armored by the Hawaii Department of Transportation (HDOT) in an epic battle against sea level rise and coastal erosion a section at a time; choice of weapon: seawalls, rock revetments and jersey barriers. Scientist Dr. Mark Deakos has been tracking the situation, and he summarized his findings: "Over five years, the HDOT would invest over $35 million to armor 22 percent of the 6.3-mile long coastal portion of Honoapiilani Highway." Further, "HDOT has armored more shoreline in Maui than all of the island's private property owners combined."

In 2013 a proposal surfaced by homeowners in Spreckelsville to build rock groins in front of their homes, with 800 cubic yards of beach fill between the groins.

The Kahana Sunset apartments are located near the water's edge at Keonenui Bay in Napili. The 4.5-acre, six-building, 79-unit apartment complex was built in 1971. Several recent storms have threatened the buildings and the integrity of a seawall built to protect them. To address this issue, the owners want to demolish a 114-foot seawall and a concrete stairway. A new seawall would be built mauka of the state-designated shoreline and a replacement stairway about 30 feet inland of the existing structure. Aside from protecting the apartment complex, the project aims to widen the beachfront and prevent dirt from entering the ocean during a storm.

An article discussing the Hale Pau Hana Seawall on Maui appeared in the Fall 2005 issue of Shore & Beach, the Journal of the American Shore & Beach Preservation Association. In the article, Ed Flavell discusses the effects of the 560-foot seawall that backs about 43% of the Kamaole II pocket beach. The seawall was built in 1969. Mr. Flavell claims that the seawall has had no deleterious effect on the beach of the Kamaole II shoreline reach. His research indicates that the seawall has ameliorated episodic storm wave attacks but has not altered other shoreline processes. Typically, the sandy beach fronting the seawall has recovered following a storm wave episode, supporting Naupaka growing on the beach and indicating shoreline accretion.


Information is available on the number of major and minor Special Management Area (SMA) applications for each county that were submitted and approved, however this information does not indicate the extent or location of shoreline armoring structures.

The University of Hawaii Sea Grant publication beach erosion and loss provides some general information on shoreline structures.

"Building walls is known as hardening the shoreline. Hardening a shoreline can interfere with necessary profile adjustments because the dune can no longer share its sand with the beach. As a retreating beach encounters a seawall or revetment it can no longer draw upon a landward sand supply and it begins to erode. Beach erosion leads to narrowing and, soon, beach loss. Much of Hawaii's beach loss could have been avoided if houses were not built so close to the water. The law presently allows homes 40 feet from the shoreline. On coasts experiencing chronic erosion this is too close and leads to hardening in order to protect houses from the waves."

Also see Coastal Erosion and Beach Loss in Hawaii.

Two journal articles with good information on beach erosion/shoreline armoring in Hawaii are:

  • Fletcher, Charles H., Robert A. Mullane, and Bruce M. Richmond. "Beach Loss Along Armored Shorelines on Oahu, Hawaiian Islands." Journal of Coastal Research. Winter 1997. Volume 13. Issue 1. pp. 209-215.
  • Coyne, Melanie, Robert Mullane, Charles Fletcher, and Bruce Richmond. "Losing Oahu: Erosion on the Hawaiian Coast." Geotimes. December 1996. pp. 23-26.

The Fiscal Year 2017 Civil Works Budget for the U.S. Army Corps of Engineers provides $4.62 billion in gross discretionary funding for the Civil Works program. This budget lists proposed projects and the associated budget justification by state.


Dolan Eversole
NOAA Coastal Storms Program Coordinator, Pacific Region
University of Hawaii Sea Grant Program

Chris Conger
DLNR-Office of Conservation and Coastal Lands
(808) 587-0377


Zoe Norcross
Hawaii Sea Grant Coastal Processes Extension Agent
310 Ka’ahumanu Ave
Kahului, HI 96732
(808) 984-3335


Adam Asquith, Ph.D.
Extension Specialist
Kaua‘i Community College
FARM Facility
Kaumuali‘i Hwy.
Lihu‘e, Hawai‘i 96766
(808) 245-8322

Perception of Effectiveness

Property in front of homes, hotels, and all other structures built on the shoreline are subject to beach erosion caused by oceanic waves hitting the islands. The old solution was simply to build a stone wall to protect the investment. This has been shown to cause great loss of sand on the beaches. Dr. Chip Fletcher of the University of Hawaii estimates that Oahu has lost 25% of its beaches, and Maui has lost 30%, due to coastal erosion. Some of the islands have enacted restrictions on walls, but still consider revetments (sloped stone walls) and groins to control sand movement. These also modify nearshore currents and sand movement, so any hardening of the coastlines should be discouraged. A major project was proposed for the island of Maui, where the state wanted to reconfigure the breakwaters at Ma'alaea Harbor. Surfrider Foundation's Maui Chapter and other environmental groups opposed the project, as it would have destroyed nearby reefs and a fabulous surf site.[3] Fortunately, plans for this project were dropped in 2012.

The 1997 Assessment reported with respect to beach erosion/hazard mitigation efforts in Hawaii that as of that time there had been:

  • Lack of a long-term commitment. Hazard mitigation efforts tend to be reactive to major hazard events.
  • Lack of political will. Making difficult decisions that protect life and property in the long-term -- for example, increasing the shoreline setbacks rather then allowing shoreline hardening as a short-term approach -- requires strong political will.
  • Hazards are not standard planning considerations. Hazard vulnerability is not a routine part of permit and other land use planning decisions.
  • Limited hazard mapping. Hazard mapping is limited in several areas of the state.
  • Inadequate coordination. There is inadequate integration and coordination between disaster response and preparedness programs, mitigation efforts, and land use planning and regulatory programs among various state, federal, and county agencies.
  • Property rights concerns. "Takings" and other private property rights issues create a difficult climate for attempting new initiatives and approaches to hazard mitigation.

A paper that provides an interesting two-state comparison of coastal armoring is Shoreline Armoring Impacts and Management Along the Shores of Massachusetts and Kauai, Hawaii by James F. O’Connell.

Public Education Program

The University of Hawaii Sea Grant program website is a good source of information on coastal hazards and related subjects like beach dynamics and sand budgets. Following are links to several such publications and a statewide erosion management plan prepared by the State Department of Land and Natural Resources (DLNR):

Hawaii Sea Grant also prepared Natural Hazard Considerations for Purchasing Coastal Real Estate in Hawai'i (May 2006).

The University of Hawaii Sea Grant publication beach erosion and loss explains the long-term effects of seawalls on an eroding coast.

Also see Coastal Erosion and Beach Loss in Hawaii.

This account is from Chip Fletcher, Geology Professor at the University of Hawaii in 2003:

"When I first moved here in 1991 the State was handing out seawall permits left and right, counties were mining beach sand for golf courses, and illegal walls were rampant. We published a paper in 1996 documenting the loss of 25% of the beaches on Oahu. That hit the papers with a big bang. Slowly the awareness level has risen. Now the state DLNR has an effective moratorium on seawalls (4 yrs old), the newspapers and TV stations see beach loss as a perpetual theme that they revisit 2 or 3 times a year, and there is a state erosion committee that meets every 2 months to discuss issues. We even have a state beach fund into which fines and fees are placed to support restoration activities. In 1999 Sam Lemmo at DLNR and I got resolutions and endorsements from every county council and state agency for a new Erosion Management Plan for the State of Hawaii that I wrote...the governor even signed it into law. That year Sam won state employee of the year and I got the University of Hawaii Clopton Award for Public Service. We gave over 75 public talks in the space of 2 years."[4]

There are links to several publications on the the Coastal Hazards website of the State of Hawaii Office of Planning and also on their publications page.

Also see the Hawaii Coastal Erosion Website from University of Hawaii Coastal Geology Group.

A summary of shoreline management in Hawaii is presented here.


  1. Written communication from Debra Tom, Planner, State of Hawaii Planning Office. July 12, 2000.
  2. Norcross, Z., Fletcher, C., Rooney, J. and Barbee, M., University of Hawaii, 2003. Erosion Hazard Mapping and Setback Calculation on Maui, Hawaii. Proceedings of the 13th Biennial Coastal Zone Conference, Baltimore, MD.
  3. Carl Berg, Maui Chapter Surfrider Foundation, written correspondence. February 11, 2002.
  4. Chip Fletcher, University of Hawaii at Manoa, email correspondence, December 16, 2003.

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