The last major valley stream in East Honolulu that’s not fully lined with concrete is now under consideration for an intergovernmental flood control study.

The proposed $3 million study of the Wailupe Stream Watershed, to be undertaken by the city Department of Design and Construction and U.S. Army Corps of Engineers, would look to plan and design flood control features to prevent potential flooding in and around communities like Aina Haina.

Wailupe Stream is one of 10 such streams that drains its watershed into the roughly 7-mile-long Maunalua Bay.

But unlike the nine other tributaries that flow into the bay, Wailupe Stream remains in a largely natural state. Therefore, according to area residents and city officials, it’s historically prone to flooding events — particularly in weather systems like Tropical Storm Hone, which is expected to bring high winds and rain to the state this weekend. A flash flood in 2018 destroyed three homes and damaged more than 150 others in the area of the stream.

“This is a significant project in Wailupe that could hopefully turn into a construction project that will improve flood conditions out there,” DDC Director Haku Milles told the City Council’s Committee on Zoning on Wednesday.

As proposed under Council Resolution 204, the Wailupe flood study would cost the city about $1.5 million. The city would pay the U.S. Army Corp of Engineers 50% of the estimated $3 million project.

The project includes “all activities and tasks required to identify and evaluate alternatives resulting in the preparation of a decision document that recommends a coordinated and implementable solution for flood risk management for the Wailupe Stream Watershed,” the resolution states.

To that end the city has identified $500,000 for this “decision document” — funds that were appropriated under the city’s 2024 capital improvement program budget, the resolution states. It indicates that the remaining $1 million would be programmed in the city’s 2026 fiscal year CIP, which does not take effect until July 1.

Army Corp of Engineers representatives did not attend the meeting.

But the potential flood control project drew support and opposition from area residents.

“Residents in Aina Haina have been seeking solutions to (the) flooding of Wailupe Stream since the 1960s,” Jeanne Ohta, Aina Haina Community Association president, told the committee. “I’ve been personally involved in seeking solutions since the year 2000.”

She added, “We’ve had many studies conducted since the 1960s. So the question is, Why would we need another study? The reason I believe we need one is because the stream has changed, even since 2018.”

Ohta noted that large boulders formerly in the stream located behind her home have disappeared.

“I don’t know where they went,” she said, “but they were huge.”

She said due to the loss of those boulders, “there was significant stream bank erosion.”

And she claimed the lower portion of Wailupe Stream, nearest the bay, suffered significant damage, too, and “has not been studied.”

“I’m asking for your support, and to vote for this resolution,” Ohta said.

Chris Cramer, co-founder of the Maunalua Fishpond Heritage Center, who lives near Wailupe Stream, said the Council should not commit to a study until the public has been better informed.

“I just wanted to oppose this resolution in its current form,” he said. “It doesn’t put any language to consult community members or Native Hawaiians who have generational knowledge or expert knowledge (of the stream).”

He said the stream has been “used for fishing and gathering for generations, and this resolution is strictly looking at flood control.”

“If you look at all of the other valleys in the Mauna­lua Bay area, they’ve all been channelized and turned into concrete, with graffiti, and there’s just nothing living in those streams now,” he said. “So we ask you to amend the language to include consultation with Native Hawaiians and recreational and subsistence fishermen.”

Cramer said the city could improve the resolution’s language “to do things that don’t cost money.”

“Don’t allow monster homes and building right in the setback,” he said. “I mean, it’s basic common sense, but the city is approving development right up against the stream, and then we’ve got to bail out these ‘monster home’ builders and folks that are building right up against the stream.”

But, according to Milles, public outreach for this project was premature.

“At this point for the resolution, I’m not sure those details should or need to be included,” he said. “I’m not an expert on these legal documents per se, but it’s the responsibility of my department to work with the Army corps and see what can be done, what should be considered, what the scope of the project needs to be.”

Council Chair Tommy Waters, whose Council district covers East Honolulu, said the city’s potential agreement with the Army corps — not the resolution itself — would need to be reviewed by both sides for future amendments.

Milles agreed.

“Our legal agreements with the corps, and the negotiations that go into that, are pretty strict,” he said. “This is something that we have our Corporation Counsel work with the Army corps lawyers on.”

Later, Ohta said she’d be cautious over any agreements with the Army Corps of Engineers.

“We’ve had mixed results with the Army corps in the past,” she said. “It’s not the easiest agency to work with, especially in a collaborative manner.”

But Waters said the project was only a proposed contract with the federal government “to study the viability and feasibility of flood control.”

“Once they come up with a recommendation, they still have to come back to (the Council) to fund it,” he said. “So at that point, if we don’t like what they come up with, we can simply say, ‘We don’t like that,’ right?”

Moreover, he noted the results of that flood control study are unknown.

“It hasn’t even been studied yet. They don’t know what to do, whether or not it’s just putting back boulders on the side of the stream or cementing it,” he said. “And really, this is something that the community should be involved in and deciding what exactly we want to see happen.”

Ultimately, the Zoning Committee voted to recommend Resolution 204 be adopted by the full Council.