New Haven residents anxious to see the long-abandoned Macy’s and O’Malley’s buildings get new tenants will have to sit on their haunches for at least a year longer than expected.

Due to the addition of a 600-space parking garage to the design plans, the slated completion of Gateway Community College’s new downtown campus has been pushed back to fall 2011.

A 1,500-space parking garage originally slated for the block surrounded by Church, George, Crown and College streets will be shelved and replaced with a newly designed 600-space parking garage built into Gateway’s new campus, New Haven Parking Authority Director William Kilpatrick said. The remaining 700 spaces, Kilpatrick said, will be absorbed into the Temple Street Garage.

“After extensive review of the [previously] proposed site, we came to the conclusion it would be more reasonable for the college to include part of the parking needs in their new building,” he said.

Gateway spokeswoman Evelyn Gard said the additional time is necessary for architects to redraft design guides and acquire approval for the proposed changes. Despite the delay, the changes should benefit both Gateway and New Haven, she said.

“This takes the burden off of [the city] and helps us,” Gard said. “Commuter students who don’t have access to public transportation will be able to have access directly to the campus.”

The construction of Gateway’s new downtown campus is part of a $230 million plan to revitalize New Haven’s aging urban core. Along with Gateway, the Long Wharf Theater, the Knights of Columbus, and assorted retail and residential units will relocate to sites currently occupied by the partially-demolished Veterans’ Memorial Coliseum and the vacant Macy’s and O’Malley’s department stores.

Tony Bialecki, New Haven’s Deputy Director of Economic Development, said the delay of the campus’ completion will not set back the overall schedule of the downtown revitalization project.

“It will free up the property and [will now] be acquired for private development,” Bialecki said. “At the end of the day it’s certainly a much more effective utilization of land.”

Because of the design changes, the site plan will have to undergo environmental impact review again before construction starts, Gard said. As prescribed by the law, two public hearings will be held to solicit community input, she said. Although architects from New York-based Perkins and Will just unveiled initial diagrams of the redesign, the revised project has not yet entered the design phase. Gard said architects plan to include at least one level of subterranean parking, with the other levels blending into the contours of the overall building.

The state, the city and Gateway have been in negotiations over the proposed changes for the last six months.