Zoo officials unveiled the proposal Thursday to neighborhood representatives, preservation groups and other interested parties that have been helping with guidelines for the zoo's expansion. The plan calls for reorienting its entryway to face into the park with a pedestrian walkway to El Prado. It would convert the current 2,700-space, ground-level parking lot to exhibit space and build a four-level underground parking garage beneath the zoo's new entry plaza.

The structure's 4,700 spaces would serve the zoo and other Balboa Park attractions. Elevators and escalators would move visitors to the entry plaza or to the Plaza de Balboa in front of the Reuben H. Fleet Science Center.

City officials will begin studying the plan next month for the required environmental impact study and public comment. Zoo officials hope to bring the plan to the Planning Commission in March 2002 and get final approval from the city by June 2002.