Crews have replaced sand that eroded away from a spot at Waikiki Beach.
Bulldozers and other equipment were brought in for the Thursday night project, timed to coincide with a very low tide.
Work was originally scheduled to take place from 10 p.m. until midnight. However, city crews started the work shortly after a makai-most lane of Kalakaua Avenue was closed for the project at about 7:30 p.m.
"The city is going to essentially scrape a thin layer of sand from a large surface of the Waikiki Beach area, kinda pile that up, and then move it with a bulldozer," said Sam Lemmo of the state's Office of Conservation and Coastal Lands, before the work began.
The sand was taken from an area near the Waikiki Police substation and put in the area near the hula halau stage. Workers had put up a white chain to keep people from falling on concrete and rebar that was exposed when the sands left. Some didn't want to have the concrete covered up until it could be determine what it was.
"The state should really call in a historical archaeologist to determine the stability of these structures, and also the history of them," said Michelle Matson of the Diamond Head Neighborhood Board.
According to one source, the concrete was once the foundation of the old Waikiki Tavern, which was on the spot until about 1960. The state is still hoping to confirm that.
In the meantime, the exposed concrete was seen as a possible hazard for beachgoers.
"This is where I normally come in and out from the break, but I went all the way around today," said Jasmine Jones, who has surfed here nearly all her life. "I can imagine if the sand doesn't fix permanently, and just temporarily, then it could be a safety hazard. You could literally trip or fall."
Officials are stressing that the work is just a temporary fix.
"Once the work is completed, we're going to be monitoring it every day to see if it becomes eroded again," said Lemmo. "In the meantime, we'll be talking about a longer-term fix."
A city spokesperson said crews will be back out again at around 9 a.m. Friday to see how high tide affects the new sand. If more sand has to be brought to the area, it will be done Friday night.