Puamana closed
Coastal erosion a beach problem
With Puamana Beach Park still closed as it faces ongoing erosion, shoreline experts say it could become the norm as rising global temperatures and sea levels continue to impact coastal beach parks and properties across Maui.
“Puamana, and many areas in West Maui, will continue to be subject to expanding and more frequent impacts from ocean flooding and erosion during periods of high tides and high waves,” Tara Owens, coastal processes and hazards specialist with the University of Hawaii’s Sea Grant College Program, said earlier this month.
The beach park, which closed Jan. 26 and was set to reopen this Sunday, will remain closed indefinitely after excessive erosion compromised the parking lot, destroyed sections of the park property and exposed Hawaiian burials, according to the county Department of Parks and Recreation. County spokesman Brian Perry also said earlier this month that there was damage to irrigation and water lines, and “a steep dropoff from park to shoreline.”
While Puamana faces a wide range of challenges, the beach park’s susceptibility to erosion is not unique, especially in West Maui.
“Coastal erosion is an islandwide problem, although there are some areas with healthier beaches and other areas with degraded or lost beaches,” said Owens, who’s also the Maui County Planning Department’s science and technical adviser. “Research based on a 100-year record of shoreline change data indicates that 85 percent of Maui’s beaches are experiencing long-term erosion.”
West Maui has been heavily impacted in recent years, Owens said, though sea level rise is a primary factor in changing and degrading most of Hawaii’s shorelines.
“Therefore, generally speaking, coastal erosion is a continuing and worsening problem,” she said.
Limited sand supply, the narrowing of beaches or lost beaches in areas where buildings and other infrastructure were built close to the shoreline are other factors that officials continue to analyze.
There are also erosion hotspots in South Maui and on the North Shore, like Baldwin Beach Park, which has been a victim of coastal erosion and sea level rise in the past.
The Department of Parks and Recreation and community members are developing a master plan to renovate Baldwin Beach Park in the future, as well as address the pavilion and other features of the park, Perry said.
A dune restoration project is also being planned to protect the beach from the impacts of sea level rise.
“There is an increase in coastal erosion at many of our coastal properties,” Perry said. “The department’s vulnerability study will address these concerns and provide the department with proposed adaptation strategies.”
Owens said mitigation and adaptation approaches usually follow four types of strategies, including protection, accommodation, ecosystem-based adaptation and retreat.
Protection usually involves physical barriers, such as seawalls.
“This has been the historical response to erosion statewide, although the consequences of this approach are now well understood to exacerbate erosion and contribute to beach loss in most cases,” she said.
Accommodation focuses on improving current developments, such as elevating a building, which can work in areas that are subject to flooding. This strategy may not be as effective for areas that are subject to land loss from erosion, she explained.
Ecosystem-based adaptation involves “preserving and restoring natural systems that buffer the impacts of erosion and flooding,” like wetlands, reefs, beaches and sand dunes.
These types of buffers are seen around Maui, including active dune restoration sites in South Maui and other locations. Owens added that there
are several beach restoration projects being proposed for West Maui coastal areas.
Lastly, retreat involves changing or relocating buildings out of hazard zones.
“This is usually accomplished through property buyouts or shoreline setbacks that are implemented incrementally over a long time,” she said. “Updated shoreline setbacks that account for sea level rise are currently proposed for Maui.”
She said that it’s important to recognize and understand that coastal erosion isn’t necessarily a problem unless and until it impacts buildings and infrastructure.
“Since there is now very good localized and site-specific information about past and future coastal erosion trends, hopefully that information will be used for proactive and adaptive planning decisions to avoid or lessen the impacts of erosion,” she said.
The State of Hawaii Sea Level Rise Viewer, which can be found at www.hawaii sealevelriseviewer.org, provides science-based information about past and future erosion trends statewide and island-wide, Owens said.
The public and officials can view information about future exposure to ocean flooding and erosion, vulnerable areas due to sea level rise, as well as potential economic impacts to land, highways, and infrastructure from sea level rise and coastal hazards.