Qualcomm founder and billionaire philanthropist Irwin Jacobs wants to make over Balboa Park for its 2015 centennial celebration.
Mayor Jerry Sanders backs the plan the plan to remove cars from Plaza de Panama at the center of Balboa Park.
But a local preservationist group has sued to stop the project. San Diego's Superior Court concurred with the Save Our Heritage Organisation that an agreement the city signed with Jacobs was illegal.
Now a state preservation official has said major changes to the park will cause it to lose its Historic Landmark Designation and possibly future funding opportunities.
Mark Johnson, the founder of Civitas, Inc., is the designer for the Plaza de Panama project. He told KPBS Television's "Evening Edition" the plan to remove cars from the park will take it back to what it once was, a pedestrian park in 1915.
But SOHO director Bruce Coons said he also supports removing parking from the park, and added that Balboa Park was built for cars.
"The only time it didn't have cars was for about a year and a half in 1915, 1916," he said.
Coons said the park losing its Historic Landmark status would be a huge blow to tourism and the park's ability to garner federal, state and local grants.
However, Johnson said he is not worried about losing the park's historic status.
"We think the improvements we are making are a great benefit, on balance and an extremely positive thing for the park that will enhance the historic district," he said.
Coons disagreed.
"We believe the park would be unrecognizable to present park lovers if this project was put in," he said.
"It would look more like a business park in North County, rather than the park we all love," he added.
Johnson disagreed with Coons' concerns and said if the plan proceeds, the park will retain its historic value.
