The beaches front Oahu’s biggest resort area outside Waikiki. The 387-room JW Marriot Ihilani Resort & Spa, a massive Disney hotel under construction that’s due to open in August, and a time-share condominium complex all overlook a series of man-made beaches and lagoons.

The state ordered the shorelines closed after heavy rains led the nearby Waimanalo Gulch Landfill to release contaminated storm water and municipal solid waste into the Pacific Ocean next to the resort area.

The state Department of Health was still testing the water on Tuesday. The first lab results from water sampling taken Thursday indicated “very high” bacteria levels consistent with polluted runoff from a storm.

The city has posted warning signs saying “Warning: Contaminated Water — No Swimming, No Boating, No Fishing” at a Nanakuli surf spot known as Tracks and down the coast to the harbor and marina entrance past Ko Olina.

The U.S. Environmental Protection Agency sent three people to Oahu — an on-scene coordinator and two engineers — to monitor the response and offer advice.

They were focused on making sure the landfill has a functioning storm water retention area and would be able to prevent a similar situation if there’s more heavy rain, EPA spokesman Dean Higuchi said.

Asked if the agency would be investigating the city, which owns the landfill, for the debris spill, Higuchi said he couldn’t say either way.

“It’s way to soon to start looking at enforcement. At this point, the focus is on cleanup. The focus is also to ensure the integrity of the landfill’s stormwater system,” Higuchi said.

“If we focused on enforcement now and forgot about the rest, it would happen again.”

The landfill, which is operated by contractor Waste Management, Inc., is due to close in 2012. The city had wanted to keep it open for another 15 years, but the state Land Use Commission rejected that plan.