The National Parks Service sent a letter May 7 to city leaders threatening that approved changes to Balboa Park could result in the loss of its National Historic Landmark status.
NPS deemed the Plaza de Panama project for Balboa Park "aggressive."
Councilmember Kevin Faulconer, who helps to oversee the project that could potentially remove the Cabrillo Bridge, was told by the NPS that the project would “have a permanent, major and adverse effect on the integrity of the Balboa Park National Historic Landmark.”
Meaning the proposed changes to Balboa Park could strip the park of its National Historic Landmark status.
Click here for a timeline of Plaza de Panama
The NPS said it wants to ensure that the historic integrity of Balboa Park is retained, and has asked Faulconer to come up with Plan B.
“The NPS believes that there are viable, less costly alternatives that would reduce or eliminate private vehicular traffic from the core without the significant impacts to the integrity of the NHLD [National Historic Landmark District] that would result from the project,” the NPS associate director wrote to Faulconer.
The department also said it questions if removing all vehicles from the park to be realistic.
Plaza de Panama has come under scrutiny from the Save Our Heritage Organisation, which filed suit in February against the proposal arguing it will destroy the park's entrance and its iconic Cabrillo Bridge.
"It firms everything that we've been saying about what's wrong with this plan, and the professionals that looked at it, and now the federal government's looking at it, and they say the same things that we say," said SOHO director Bruce Coons.
The project would rely exclusively on private donations and bonds. So far, the price tag is roughly $40 million and has three more committees to go through, before the San Diego City Council reviews it in July.