Oahu residents who suffered property losses from flash floods April 13 had their first opportunity at one-stop relief assistance shopping Monday.

The city Department of Emergency Management has organized four pop-up disaster recovery centers, the first of which opened in a Waimanalo District Park multipurpose building.

The centers are offering a range of information and services, including property tax break applications, fee waivers for building permits on repair work, low-interest loans, volunteer manpower, American Red Cross cleanup kits and state Department of Health information on mold.

Fourteen city agencies, state agencies and nongovernment organizations are participating.

The next three centers will open at Koko Head District Park in Hawaii Kai today and Thursday from noon to 8 p.m. and at Waimanalo District Park on Wednesday during the same hours.

As of Monday 199 homes mostly in Niu Valley — but also in Kuliouou, Aina Haina, Waimanalo, Hawaii Kai and Kailua — have been certified as damaged by the Red Cross. This includes 56 homes where more than 18 inches of water filled an essential living space, and 120 homes where up to 18 inches of water filled an essential living space.

Waimanalo resident Johnny Michaels was one of about a dozen people who visited the recovery center Monday afternoon. He sought help after the street he lives on, Mekia Street near Shima’s Supermarket, turned into a river April 13 when a drainage ditch blocked by a tree overflowed.

Michaels was glad he attended, though he was dejected over not being able to get compensation for the loss of tools and machinery that he said were carried away by the flood, plus two cars that got soaked, including one he usually drives for Uber on Fridays, Saturdays and Sundays.

The Uber driving, Micheals said, could provide him with $700 a week to supplement his income as a debt collector for companies in the produce business.

“I can’t drive,” he said. “I can’t make the rent.”

Michaels said most assistance at the center was geared for homeowners. In his case he must rely on car insurance, though he said he plans to file a claim against the city because it wasn’t adequately maintaining the drainage ditch that crosses under Mekia Street and has been subject to previous floods that don’t come close to the one on April 13 where water rose about 2 feet outside his residence.

“It overflows all the time,” he said. “This becomes ‘Lake Mekia.’ You can go rock fishing over here.”

Neighbor Danford Aguiar on April 13 helped stop traffic from coming up the road and running into the rising floodwater. On April 14, he said, state officials came out and declared that they couldn’t clear the blockage in the ditch caused by a tree with a 27-inch-diameter trunk.

“They said they can’t do nothing about it,” Aguiar recounted.

So Aguiar, who works in the construction trade, decided with his family to get an excavator to do the job themselves. He said they cut up the tree into several large pieces with chain saws and hauled out the pieces.

City and state agencies have been backlogged with cleanup work, including debris that has piled up in parts of the Ala Wai Small Boat Harbor, rivers, drainage ditches and stormwater detention basins.

The city has been making extra bulky-item pickups in affected areas to haul away damaged home contents. And the city also has picked up loads of dried mud cleared from residences. The city Department of Design and Construction, along with the state’s Hawaii Emergency Management Agency, has made a preliminary $7.3 million damage assessment to public infrastructure on Oahu.

That will allow the city and state to start a process to seek reimbursement from the Federal Emergency Management Agency for up to 75 percent of repair expenses.

FEMA assistance also can be made available for private-property losses, depending on the loss total still being compiled by the Red Cross.

Specific help at the disaster recovery centers available now includes possible refunds of some property tax payments this fiscal year. There is no formula, but they depend on the damage value and property taxes paid. The city Real Property Assessment Division plans to notify homeowners who have had properties inspected by Red Cross officials about this offer.

Building permit fees for home repair work also can be waived, saving a couple hundred to a couple thousand dollars in many instances.

The city Department of Community Services is making available low-interest loans for home repair work.

A collection of volunteer groups, including churches and community organizations under Hawaii Voluntary Organizations Active in Disaster, are providing help with hauling damaged items out of homes and other work.

Other help offered includes agriculture loans and possible extensions for paying state taxes.