City and state officials missed a Wednesday deadline to reach an agreement that would have given them access to $220 million in federal funding to shore up the Ala Wai Canal and its watershed to protect Waikiki and several other Oahu neighborhoods from flooding.

The Army Corps of Engineers was supposed to find a sponsor for its $345 million Ala Wai Flood Risk Management Project by Wednesday. To lessen flood risks, the corps would build a wall around the canal and put huge flood-control structures in the upper reaches of the watershed.

Now the loss of millions in federal funding may be imminent, unless corps officials in Washington, D.C., agree to an extension. The state has agreed, at least in theory, to pay $125 million for the project, the amount required to receive the $220 million in federal funds. The city has agreed to serve as the project’s sponsor and maintain what gets built. But as of Thursday the parties were still at an impasse.

The project’s fate is now up to corps officials and the assistant secretary of the Army for civil works, said Andrew Pereira, Mayor Kirk Caldwell’s communications director.

“The city provided the U.S. Army Corps of Engineers with a road map and a time frame for signing (a proposal),” Pereira said. “The city has not heard back whether the proposal was accepted.”

The corps did not respond to the Honolulu Star-Advertiser’s request for comment.

Krishna F. Jayaram, special assistant to the attorney general, said Thursday that “conversations are ongoing between the state and the city, but I don’t have anything else to share beyond that.”

The deadlock goes back to the state’s failure to secure $125 million in this year’s budget to meet the federal cost-share requirement. State officials didn’t view this as a major setback, initially, because the federal government was willing to take the money in future installments. However, the state didn’t count on the city’s reluctance to serve as a sponsor on a project that wasn’t fully funded and would therefore require the city to assume more risk.

Sidney Lynch, Waiomao Stream Homeowners’ Association president, said she hopes that the missed deadline will provide a chance for officials “to reevaluate and examine the plan to come up with more equitable flood mitigation that doesn’t just block the water from Waikiki and provides for some ecosystem restoration.”

Lynch, who lives on streamside property that is below a proposed dam, was one of the testifiers who got the Honolulu City Council to unanimously pass a resolution asking Caldwell not to sign with the corps until the project was reevaluated. Seven out of eight neighborhood boards in the Ala Wai watershed also passed resolutions urging government officials to delay the project, she said.

But Waikiki Neighborhood Board member Jeff Merz said he’s disappointed that officials missed the deadline, and is now calling for them to provide an update.

“It’s still unclear to me what all of this means. I would have hoped that they would have asked for a deadline extension and worked hard to address project concerns on both sides. But, if they messed up and missed the date, we have a right to know that the money is gone. We also deserve an explanation of what they plan to do from this point forward,” Merz said.