Orange County is set to finalize its plan to develop 108 acres just south of the Great Park into a massive commercial and residential complex – a move that could initiate a legal showdown with Irvine, where officials claim it could prevent the development of a public amphitheater, museum and other facilities.

The county has refuted the city’s assertion and is moving ahead with the project.

On Friday, the county released its final Environmental Impact Report detailing its plan to build 1,998 housing units, 1 million square feet of office space, 200,000 square feet of commercial space and a 242-room hotel on land it kept when it annexed the Great Park to Irvine in 2003. Once completed, the project could earn the county upwards of $4 billion over 75 years, giving it a new revenue stream for countywide infrastructure improvements and to help the homeless.

The county’s Board of Supervisors will vote whether to certify the document on Nov. 14, potentially beginning the next phase of development.

The project has been controversial locally in part because it will increase traffic in an area where developers and the City of Irvine also are competing to claim limited road space for their own projects.

Irvine city officials say the county’s complex could crowd out its planned 233-acre Cultural Terrace, preventing the city from completing the final major piece of the Great Park, which could include an amphitheater, museums, a library, a lake and a water park. The county disputes that its project would impact the city’s plans, saying its complex leaves enough road space for the Cultural Terrace and other private developments.

Despite those assurances, several Irvine City Council members have threatened a lengthy legal battle if the county moves ahead with the project.

“If it impacts our Great Park to the point where we can’t build it out, of course we would be looking into litigation,” Councilwoman Christina Shea said Monday. “I don’t think the county should be getting into the business of retail and housing.”

Irvine Mayor Don Wagner agreed, saying the City Council “is not just going to accept this as a done deal and move forward.”

In late 2016, the cities of Tustin, Laguna Beach, Lake Forest and Irvine also lodged official traffic-related complaints or comments about the project as part of the planning process, saying local roads and freeway exits weren’t big enough to handle the 35,000 additional daily car trips the county’s project will add to the area. The cities contend that the added traffic will cause gridlock beyond Irvine’s borders.

The county’s final report makes some concessions, pitching a development that is slightly smaller than the largest project envisioned in the draft planning document released in November 2016. The complex described in Friday’s report has 900,000 fewer square feet of office space and 105 fewer housing units than the largest possible option proposed last year. That reduction means the development is estimated to add 12,000 fewer average daily car trips than the maximum 47,000 trips originally projected.

Friday’s report acknowledges the development will impact traffic in the area. But it states the county and its developer for the project, Lowe Enterprises, will address that burden by paying to add freeway ramp lanes, change traffic signals and eventually widen surface streets in the vicinity – though most of those improvements aren’t required until 2035 and beyond.

Irvine city officials say the smaller development and planned road improvements don’t assuage their worries.

Irvine and other potential litigants will have 30 days from the board’s vote to sue over the plans. If Irvine files a lawsuit, it likely will be over whether the county’s 2003 agreement with the city to transfer control of the Great Park allows the county to build a commercial development. The city thinks the agreement limits the county to government uses on the land. The county disagrees.

The county’s Great Park-adjacent project is part of its larger plan to monetize land it owns by developing the parcels and using the revenue for infrastructure improvements and other costs. In Oct. 2016, county supervisors voted to lease part of a flood plain it owns in Chino to be developed into warehouses, a decision which could bring in an extra $523 million over the next 67 years. Similarly, the county was working to develop 22 acres it owns in Laguna Niguel into the city’s first downtown area before that project fell through recently.