LIHUE — King tides have returned, triggering flooding at Nawiliwili on Monday afternoon.
They’re technically set to arrive today and tomorrow.
And while the king tides aren’t related to sea level rise or climate change, Kauai’s coastline is still crumbling and the highest tides of the year could start pushing water levels closer to infrastructure.
King tides are already causing some problems on other islands, like Oahu, where the summer 2017 king tides in Honolulu backed up into the stormwater system and out into the streets.
On Kauai, scientists say that king tides haven’t started causing problem to infrastructure yet, but several years ago they did impact salt-making.
“We have seen Hanapepe Salt Pond getting flooded during the king tide combined with a south swell and that ruined an entire salt-making season few years ago,” said Ruby Pap, coastal land use extension agent for Hawaii Sea Grant.
But, she says, sea level rise combined with the highest tides of the year could lead to more problems on Kauai.
“Especially if high tides are combined with a swell, where we could see more beach erosion or wave runup into sensitive areas,” Pap said. “Having a high tide combined with large waves can often make all the difference in inundating an area.”
The highest tides of the year are arriving July 2 and 3. High tide today arrives at 3:16 p.m. in Hanalei, 4:17 p.m. in Nawiliwili Harbor and 4:30 at Waimea Bay. High tide on July 3 will start at 4p.m. in Hanalei Bay and at 5:05 p.m. at Waimea Bay.
Sea Grant is part of the photo project to document these tides and the damage they cause. Citizen science is an integral part of that project and as the king tides arrive, organizations are asking people to take pictures of the process.
Anyone with a camera or cell phone can snap a couple shots of the year’s highest tides and submit them to the project online.
“We want to document it because the threat will increase with sea level rise and we need to prepare,” Pap said. “Ideally we are documenting lots of different areas during the King Tides so that we know more and more what to expect in terms which areas flood and which do not.”
Judging what areas will flood can be based, at least partially, on infrastructure and resources located in low-lying areas.
Pap says simply, “if you know an area that is an erosion hotspot or often floods along the shoreline, you will probably see flooding during the king tides.”
Kauai, overall, has been experiencing coastal erosion. The shorelines are changing. And there’s infrastructure located very close to the shoreline all around the island — including homes, businesses and Kuhio Highway.
“You can see the evidence of erosion problems from sea wall and sand bag construction along coastal areas in Kapaa, Hanalei, Anahola, Kekaha Poipu… 70% of Kauai’s beaches are chronically eroding and this is from evidence over the past century,” Pap said.
With sea level rise, which will add anywhere from 1-6 feet or more over the next century, those impacts will be greatly magnified, scientists say. Kauai is also expected to see more wave runup, passive flooding, and groundwater flooding.
Submit photos to pacificislandskingtides.org.