A master plan that would guide a monumental resculpting of the state’s biggest park in urban Honolulu and add new uses including sand volleyball courts, an oceanfront amphitheater and a beer garden failed to win support of a state board Wednesday.

Board members of the Hawaii Community Development Authority decided not to adopt the plan that has been three years in the making and based largely on public input.

Instead, the board formed a task force with four of its members to envision potential amendments to the plan for the 39-acre Kakaako Waterfront Park and two neighboring parks owned by HCDA.

One big reason for the board’s decision focused on unknown costs for perhaps the most dramatic change envisioned for the park — eliminating some of the hills that rise up to 50 feet, so that visitors can see the ocean from a main entryway.

“I’m not comfortable adopting this plan,” said board member Beau Bassett. “I wouldn’t want to have a master plan that has these great things that are fiscally unachievable.”

Jesse Souki, executive director of the agency overseeing development in Kakaako, said the plan provides a more high-level view of aspirations, and that adoption would allow the agency to progress to next steps that include implementing some of the more easily achievable improvements while working toward more challenging and costly goals.

The effort to redo the park partly grew out of the fact that it is not well used despite growing outdoor recreational needs for an area undergoing a population boom from condominium tower development.

HCDA built the oceanfront park in 1992 to cover a municipal landfill that operated on much of the site from 1930 to 1977.

The park redevelopment plan, which local planning firm PBR Hawaii produced for HCDA, estimated costs at $44.5 million and 20 years to implement.

Plan features include 12 sand volleyball courts with bleachers, a gym, children’s play structures, a community center, a water splash pad, a beer garden, a food truck court, more restrooms and a “beach hale” near Point Panic that could include surfboard storage and maybe a food concession.

A parking lot in front of the park would be shifted to other areas fronting adjacent roads to create an entry plaza. One inland hilly area would be made into an “adventure zone” with slides and possibly rock climbing features or rope courses, while another hillside would be sculpted into amphitheater seating facing a stage on the water’s edge.

However, recontouring park hills and removing one large central mound to create an inviting ocean view from Ala Moana Boulevard involves unknown costs not included in the $44.5 million estimate.

A consultant on the plan, Element Environmental LLC, reported that little is known about the landfill’s configuration and contents because of a lack of records.

Bassett said he wants to know the costs for altering the landfill before adopting a plan calling for such work. “I would hate to adopt a vision that is totally unfeasible,” he said.

Tom Schnell, a PBR principal, said identifying such costs will require further study and detailed plans for the amphitheater and view channel.

“It could be a high cost, but our task was to create a master plan and not to design the details,” Schnell said. “It’s not impossible to move the mounds.”