The inundation overwhelmed the sewage system, causing 500,000 gallons of wastewater to spew from manholes, said Lori Kahikina, Honolulu's director of environmental services. "Now's not the time to go swimming," she told reporters.
It could be a couple of days before the ocean is clear enough for people to enter, Kahikina said. It would likely take that long for water samples to be tested for safety, she said.
Waikiki is home to many of the state's biggest hotels and is the engine of Hawaii's tourism-dependent economy.
The city is advising people to avoid a 4-mile stretch of waterfront from Kapahulu Avenue in Waikiki to Point Panic in Kakaako. Sewage came out of manholes at Ala Moana Beach Park, on a street fronting a shopping mall at the edge of Waikiki and a pumping station.
Waikiki was not the only area of Oahu that was affected by an overflow of wastewater. The state Department of Environmental Services said Monday that Kailua, Kaneohe and Kalanianaole Highway in Aina Hina also experienced overflowing sewer systems. The Department of Health issued warnings for people to stay out of the water in all affected areas, including Kaneohe and Mamala Bays.
Shayne Enright, a spokeswoman for the city's Department of Emergency Services, cautioned that going into the ocean could be dangerous. "We don't know right now what is in the water. You could get a serious infection, get extremely sick or even worse," she said.
Kahikina says the storm water entered the sewage system as leaves and debris clogged the storm drains. She said some witnesses reported people were opening manhole covers to let the storm water drain into the sewage system, even though sewage pipes and pumps aren't designed to handle that volume of liquid. It's illegal to open manhole covers, she said.
In 2006, the city temporarily closed Waikiki's beaches after 48 million gallons of raw sewage poured into the Ala Wai Canal bordering the area's hotels and condominiums. That spill occurred after a sewage line ruptured following weeks of heavy rains, forcing the city to divert wastewater into the canal.
Rain and thunderstorms on the islands had prompted statewide flash-flood warnings and watches.
Meteorologists with the Central Pacific Hurricane Center said Kilo will pass by uninhabited Johnston Atoll on Monday night and strengthen over the next few days, but the storm was not expected to directly affect any other landmasses.
Still, the forecast calls for more rain and high humidity for Hawaii throughout most of the week.
"It's going to get a little bit better into midweek, but it's still going to be quite hot and humid and the potential for the heavier showers remains pretty much throughout the week," said meteorologist Ian Morrison.
Lifeguards were warning visitors to all island beaches about a brown water advisory issued by the Department of Health, saying that flood waters might be contaminated.
The Associated Press