The operator of Oahu’s only landfill has one week to come up with a plan to avoid a repeat of the events that sent storm water with medical waste and other trash into waters at the edge of Ko Olina Resort.

Waste Management Inc. has already begun corrective action, but the federal Environmental Protection Agency’s administrative order yesterday sets a schedule for the required improvements.

There are no fines levied, but that could change if Waste Management fails to meet deadlines, said EPA spokesman Dean Higuchi.

A "functional storm water diversion structure" above a landfill cell that flooded, sending contaminated runoff to the beaches, must be constructed within 21 days of the effective date of the order, dated yesterday. Joe Whelan, Waste Management general manager, had previously said the company was about three weeks away from completing a partially constructed diversion system when the storm hit.

City officials said the bypass system likely would have diverted most of the water coming from above the landfill.

"We are working with the EPA on a consent agreement … dedicated to memorializing the work we need to do to get the landfill back into pre-storm shape," Whelan said.

Waste Management, which has a contract with the city to operate the landfill, has until tomorrow to submit a list of entities it has hired to make the improvements.

Within seven days of the order, Waste Management must also submit work plans to restore a sediment basin at the bottom of the landfill site that overflowed. It caused water that had gone through the landfill cell — and an undocumented amount of debris — to pour into a storm drain that leads directly into the ocean.

During that time frame, the company also must submit work plans to ensure there is an ongoing daily beach assessment and a strategy to guarantee future storms do not cause landfill cells to overflow and end up in the ocean.

Within 14 days the company must also submit a plan to restore the integrity of the liner system in the damaged landfill cell.

Starting tomorrow, Waste Management must also provide the EPA and state Health Department detailed progress reports on its improvements.

Failure to implement the requirements of the order would result in fines: $500 a day up until the 14th day, $1,500 through the 30th day and $3,000 for subsequent days. Failure to submit timely or adequate reports would result in penalties from $250 to $2,000 a day.

"This catastrophic failure subjected Hawaii’s residents, visitors and coastal waters to a deluge of contaminated runoff, medical waste and other trash," said Jared Blumenfeld, EPA regional administrator for the Pacific Southwest, in a statement. "Our order requires immediate cleanup, continued monitoring of the beaches, and enhanced controls for storm water runoff."

The National Weather Service estimated 11 inches of rain fell into the Waianae area from late Jan. 13 through early Jan. 14.

City officials told City Council members Monday that 200 million gallons flowed into the landfill from a watershed above it, sending waste material including medical syringes and needles to accompany a torrent of storm water into the ocean.

West Oahu beaches were shut down from Jan. 14 but were reopened Sunday after no waste had been found for several days. A Waste Management official yesterday said no waste has been found along the shoreline recently.