On Tuesday, September 24, 2024, with the first sizable north swell of the season, a private home collapsed into the ocean at “Kammies” (also known as Kammieland) on the North Shore at Sunset Beach, Oʻahu. This area has experienced extreme erosion over the past 10 years, compounded by climate change-induced sea level rise and land subsidence (sinking), resulting in the destruction of multiple public and private structures. This event is the second of its kind, with the first being a house that collapsed at nearby Rocky Point in 2022.
The erosion of our beaches is a serious problem nationwide and the North Shore of Oʻahu is one of the “hot spots” for severe coastal erosion in Hawaiʻi. The rate of erosion, due to the increasing intensity and frequency of flooding and storms related to climate change, is putting great pressure on the balance between the protection of private land ownership and the conservation of our beaches and public trust resources.
The North Shore of Oʻahu is known for its world class waves and idyllic beaches that are highly utilized by local residents and an estimated 2.4 million tourists annually. But beneath this beauty is a serious environmental crisis. The majority of beaches on the North Shore (73%) are presently undergoing chronic erosion with progressive inland movement of shorelines, leading to seasonal and permanent beach loss.
O‘ahu’s North Shore is highly dynamic due to exposure to extremely large waves in winter months, which drives both seasonal and long-term beach erosion and wave runup (coastal marine flooding). The recent events at Kammies are representative of a crisis facing many nearby homes. Approximately two-and-a-half miles of beachfront residential North Shore properties are within 20 feet or less of the shoreline, which is deemed an “emergency” by state standards.
Beyond the loss of property to the homeowners, the catastrophe of homes falling into the ocean has a widely spanning ripple effect posing significant health and safety concerns to the community and shoreline environment. When homes collapse onto the beach and into the sea, hazardous debris including glass shards, electrical wiring, plumbing, chemical pollutants, and wastewater can seriously harm humans, marine life, and coastal ecosystems.
The State has jurisdiction and ownership of coastal land makai (seaward) of the shoreline, which is defined by State law as that line generally demarcated by “the highest wash of the waves.” As such, when a home collapses onto the beach and into the ocean, it is trespassing on State land. Accordingly, and in an effort to get the hazardous debris removed swiftly from the shoreline, the Hawaiʻi Attorney General filed a lawsuit against the property owner on September 24th seeking to force him to clean up the debris. The City and County of Honolulu Department of Planning and Permitting (DPP) has the authority over the area mauka (landward) of the shoreline. On September 25, DPP granted an emergency permit and order for demolition of the home that had collapsed.
The interagency cooperation and swift response to the collapse and erosion undermining these homes is unprecedented. A joint press release (9/28) between DLNR, Governor Green, and DPP states that “landowners are urged to be proactive and take all necessary precautionary measures to avoid potential damage to their property, impacts to adjacent state and/or county lands, and public access to transit the beach. If the private landowners fail to take appropriate action, the DLNR and DPP may be compelled to take administrative or legal action to protect the public health and safety.” This statement, while demonstrating significant concern on behalf of the State and County, is vague in establishing exactly what “precautionary measures” they are expecting of homeowners. The question remains: what can be done to protect the North Shore’s beaches in light of severe erosion and climate change-induced impacts to the coast?
Beach erosion has been happening for decades on the North Shore. Up until 1975, the state allowed sand mining of some North Shore beaches, exacerbating coastal erosion. And yet, many homes have been built along the coastal shorefront dunes, within the active beach system. Today, the North Shore has extensive residential development and transportation infrastructure along the coastline.
Protective management measures have historically come in the form of coastal armoring. Today, more than 10,000 feet (or about two miles) of the North Shore is lined with concrete seawalls and sloping rock revetments. Even more stretches of the beaches have “burrito” installations — tarps, geotextile bags, and other materials — which are generally all illegal now under state law, including Act 16 (2020).
On chronically eroding shorelines, coastal armoring exacerbates erosion. Beaches are naturally active systems, and armoring blocks a significant portion of sand in the dune system that would normally replenish the beach. Additionally, not only do coastal armoring measures restrict and often block public beach access, but the most detrimental effect is that it accelerates erosion. Instead of absorbing wave energy like a beach normally would, armoring reflects wave energy, increasing erosion at adjacent beaches and in front of the seawall causing the beach to steepen, through a process known as scouring. Not only does this increase erosion but it can cause a backwash on surfing waves that can be a detriment to surfing and other recreational activities.
According to NOAA, with an intermediate-level projected sea level rise scenario of 3.2 feet, approximately 1,310 buildings would be at risk — the vast majority of which would be residential single-family homes on the North Shore (link to report). In addition to these projections, there is robust collective modeling that depicts a future where beachfront development on the North Shore is no longer sustainable.
Inland relocation or realignment of coastal structures, sometimes referred to as managed retreat, is complex and nuanced. Because Hawaiʻi’s beaches are part of Hawaiʻi public trust and private shoreline armoring is prohibited, for areas like Sunset Beach that are facing sea level rise and chronic coastal erosion, retreat is the only viable long-term option.
An integrated and comprehensive approach is needed. This is a community issue, not just an individual homeowner issue. Many local families have lived in these shorefront properties for generations with nowhere else to go. On the other hand, many beachfront residences have been purchased within the last decade and those properties are speculated (within the North Shore community) to be illegal vacation rentals. As an example, 65% of residential oceanfront homes within the Sunset Beach area have been recent transactions since 2012 (figure below with link).
Figure 1. Most recent transaction year for each beachfront property in Sunset Beach study area (page 49 of UH Mānoa Institute for Sustainability and Resilience 'A Study of Shoreline Regulations and Managed Retreat for Hawai‘i A Cost Analysis for Paumalū, O‘ahu, 2023')
There is no simple solution here and we must be creative to balance the needs of our coasts and communities and also allow for subtleties when approaching different types of beachfront properties. This is by no means a one-size-fits-all situation.
A recent 2023 University of Hawai‘i at Mānoa study looking at retreat options for sandy beaches, a few different options were outlined:
Unmanaged or reactive retreat is the costliest and most damaging option for the beaches and waves of the North Shore, while all-at-once retreat can be socially and politically challenging at best. The recent events at Kammies are an example of a reactive approach — the most costly for private-landowners, hazardous to public health, and most demanding on state enforcement. The threshold-based retreat option is the most feasible and recommended approach in terms of cost, public safety, and community involvement. For a successful approach, coastal communities and government agencies should collaboratively determine the thresholds for retreat and develop an equitable retreat policy that protects homeowners and public safety, but does not retreat prematurely.
In the days following the September 24th house collapse, Surfrider has advocated for the immediate removal of hazardous debris and timely inspection of cesspools by DOH. Surfrider advocated that the State and County (link to letter) exercise their authority of eminent domain for public purpose, in order to fully remove the hazardous structures and close the cesspools which risked severely impacting ocean water quality — and to return the land to the public trust. This approach would mitigate dangerous coastal hazards, allow the shoreline to find its true natural position, and allow for dune restoration that will help to ultimately stabilize the shoreline.
This recent event serves as a highly-visible, wake up call prompting the need to craft and enact long-term, proactive measures for the North Shore coastline. In 2021 and 2022, the Surfrider Oʻahu Chapter, in partnership with the University of HawaiʻiSea Grant Program and SSFM International, launched a North Shore Coastal Resilience Working Group (NSCRWG) to facilitate community-driven discussions regarding the future of coastal management on the North Shore and released a report (October 2022) detailing critical concerns and recommendations for immediate action.
One recommendation from the working group was the development of a comprehensive North Shore Beach Management Plan to provide extensive analysis of the existing state of the beach from Sunset Point to Kapo`o (Sharks Cove). Legislation was signed into law this summer to fund the development of a beach and dune management plan by Hawaii Sea Grant. A part of this plan will include demonstration dune restoration projects to aid in beach stabilization and erosion control.
While the North Shore Beach Management Plan is a much needed first step, the recent collapse of a home at Kammies demonstrates the need for urgent action on the North Shore. As such, Surfrider is reinstating the North Shore Coastal Resilience Working Group (NSCRWG) with relevant stakeholders, decision makers, and community members to identify additional actions needed to protect this stretch of coastline.
Surfrider aims to establish renewed stakeholder discussions through the reinstatement of the NSCRWG, wherein we can explore the various managed retreat options and potential coastal adaptation pathways along the North Shore, to protect the future of our coasts and communities for generations to come.
We are also working on establishing public meetings with relevant government representatives, research scientists and the community in the coming months where we aim to facilitate honest and transparent discussion. This is a complicated and contentious subject, but the only way forward is to have these difficult conversations.