‘Perfect storm of erosion’ washing away West Maui beaches
Possible solutions range from building seawalls to moving further inland
A “perfect storm of erosion” has swallowed up much of West Maui’s beaches over the past three years due to El Nino conditions, record-high sea levels and sustained waves from the north, according to one coastal engineer working on projects along the shoreline.
“West Maui is one of the biggest problem areas in the state,” Jim Barry of Sea Engineering Inc. said Friday. “What the future holds is really unclear. Is there enough sand? Are we going to get south swell or north swell? It’s a roll of the dice, basically.”
County officials, private landowners and others are increasingly seeking help from coastal engineering firms as beaches continue to erode across the west side of the island. Sea Engineering prepared a report for the county Department of Public Works after evaluating shoreline erosion at Kaopala Bay and its encroachment on Lower Honoapiilani Road.
On Wednesday night, Barry presented his report to residents, while county officials presented possible solutions that ranged from seawalls to a managed retreat, which included converting the road to a pedestrian and bike road.
The Public Works Department is in the process of temporarily repairing a 30-foot section of the road and mulling long-term protections for the bay. Concerns over the road include damage to three underground utility lines, which could cut off water and sewage services to a number of West Maui residents.
Following a Maui News story published on Page A1 and continued on Page A2 Thursday, Public Works officials clarified Friday that long-term solutions are not limited to the 30-foot section in the bay. Officials also noted that the department has no intention of closing any other roads, unless they’re deemed unsafe.
Barry said that coastal engineers have seen sea elevation a half a foot above predicted tides for the past several years due to El Nino conditions. He said it suddenly raised to 1 foot in 2016.
“Then we were like what the heck is going on here,” he said. “It’s a huge increase. The direct effect is more wave energy at the shoreline. When the tide is high, your wave height is bigger, the waves run up higher, it erodes more and transports sand faster.”
The University of Hawaii has attributed the 2016 rise to mesoscale eddies, or large systems of warm and cold rotating ocean currents, Barry said. The cold currents act as holes in the ocean, but the warm currents act as a hump that boosts sea levels.
Barry said he is skeptical of the college’s explanation and has questions when looking at the tidal records. He said it took the college awhile to land on the conclusion and believes more research needs to be done.
Aside from elevated sea levels, a continuous north swell has pushed sand down West Maui shores and left beaches exposed to erosion.
Barry said there has been limited wave activity from the south for the past three years, but a strong south swell last month has helped push some sand north. Ideally, waves push sand south in the winter and north in the summer across West Maui beaches.
“In my 30 years in Hawaii, I’ve never seen three summers of such a lack of a south swell,” Barry said. “You can see the effects.”
In January, The Sands of Kahana Resort and the Ka’anapali Beach Hotel obtained special management area emergency permits to install protective materials along the shoreline. Rapid erosion at both hotels came within 20 feet of buildings and began to undermine a beach walk area.
Beach nourishment programs are underway with one led by the Kaanapali Operations Association in the middle of an environmental impact study. Once completed, sand could potentially be returned to beaches in the fall of 2019 or 2020, county officials have said.
* Chris Sugidono can be reached at firstname.lastname@example.org.