From Salt Lake County’s perspective, Olympia Hills is a go.

With a second 6-to-3 vote Tuesday, the County Council approved a series of zoning changes allowing the high-density 933-acre development just west of Herriman to be built as a master-planned community, akin to Daybreak in South Jordan.

But don’t expect construction workers to get started right away. One of the project’s developers said they were likely months or more away from submitting their first detailed community-level plans for county approval and it could be a year before crews get to work.

That’s if opponents are thwarted in their effort to reverse the County Council’s decision. They have planned a news conference Wednesday to announce a referendum effort. State law sets a high bar for such campaigns.

“To govern by referendum is not a good way,” Herriman resident Teddy Hodges told the council. “It’s going to cost a lot of time, sacrifice and money to get this on the ballot, but it can be done.”

After applying for and securing initial county approval for a petition on land-use policy, opponents would have 45 days to gather signatures from 16% of Salt Lake County’s active voters, both countywide and within at least five of the county’s seven voting districts.

Organizers with a group called Utah for Responsible Growth, which is fighting the project, were actively raising money and seeking volunteers this week in advance of that referendum campaign.

Plans for Olympia Hills call for as many as 6,330 new single-family homes, town homes and apartments and 1.8 million square feet of office and retail spaces to be built over 25 years in that unincorporated southwest corner of the county.

Supporting County Council members have voiced confidence the controversial project would avoid sprawl, help meet regional housing demand and unfold in the best interests of residents — thanks in part to an in-depth review by county planners and outside consultants.

The county’s agreement with developers Doug Young, John Gust and partners — also approved Tuesday — includes unique rules requiring them to pay for the impacts of their work on area roads and other utilities both inside and beyond the project’s boundaries, supporters noted.

Several dozen area residents and elected officials attended Tuesday’s hearing in County Council chambers and via phone, many of them adamantly opposed to Olympia Hills over its potential impacts on the quality of life in nearby Herriman, Bluffdale, Riverton and adjoining communities.

“We’re not afraid of change,” said Herriman Councilman Jared Henderson. “We are the change and you’re ignoring us. We want growth. We want to see it done in a responsible way.”

County Councilman Steve DeBry, who opposed the project along with council members Aimee Winder Newton and Richard Snelgrove, said the council’s final approval failed to represent the views of county residents.

“Let’s slow down,” DeBry implored before the vote as he led a failed attempt to delay approval. “This impacts people big time.”

Several opponents said they had begun new negotiations with the developers behind Olympia Hills and urged the County Council to delay any action to let those talks take shape.

Nine of every 10 facts cited in the county’s review “has been wrong,” argued Herriman City Councilman Steve Sherman. He and others continued to voice worries about more traffic, overcrowding in public schools, water supplies and other possible effects from a project that big.

“Utah does not have a housing shortage. We have a surplus,” Sherman said. “What we do have is a shortage of certain kinds of housing in certain markets.”

But Olympia Hills and its latest housing density of roughly 6.9 homes per acre, Sherman said, does not solve that problem. And he warned the county had not adequately involved city officials in the southwest part of the valley in its review.

Justin Swain, Herriman resident and organizer with Utah for Responsible Growth, told council members their approval of Olympia Hills risked disappointing hundreds of thousands of residents who have already seen other ill-planned housing projects transform their neighborhoods for the worse.

“It’s not because we are NIMBYs. It’s not because we hate growth. It’s certainly not because we hate multifamily housing,” Swain said of the opposition, referring to the acronym for “not in my backyard.”

“It’s because we love our community. We’re tired of the same things happening again and again and again,” he said.

One of the developers behind Olympia Hills, Cory Shupe, said Tuesday they will now begin work on its first community structure plan. That, he said, will have specifics on where the project’s first batch of up to 1,440 single-family homes, condos and apartments and roughly 789,000 square feet of commercial space would be built over the next seven years.

Initial maps produced by the county show the project’s first two phases, involving some of the most dense stages of Olympia Hills, would be located right on Herriman’s borders. But Shupe said developers may revise that approach, based on market conditions.

The resulting application, Shupe said, will then be subject to county review and approval, including additional traffic analysis and studies of the project’s plans for commercial buildings.

“It’ll be a very long process,” he said.

A prior version of Olympia Hills also won approval by the County Council, in 2018, only to be vetoed by then County Mayor Ben McAdams after several massive public rallies and other signs of opposition.

Prompted by state lawmakers who represent voters in the southwest part of the county, McAdams, now a member of Congress, issued a short statement Monday saying he continued to oppose Olympia Hills and urging county officials to “go back to the drawing board.”

County Mayor Jenny Wilson confirmed moments after Tuesday’s vote she will not veto the zoning changes, saying that after lengthy negotiations with the developers, “I believe this project is as strong as it can be.”

“The alternative to Olympia Hills is continued sprawl,” Wilson said in a statement. Piecemeal development, Wilson said, “will result in higher infrastructure costs, loss of valuable open space, increased transportation and travel costs and a negative impact on quality of life.”

Correction: 10:52 a.m., March 5, 2020 — Under Utah law, proponents of a referendum initiative on land-use policy in Salt Lake County need to gather signatures from 16% of active voters. A prior version of this story misstated that percentage.