ANCHORAGE -

The Alaska Zoo is planning to expand its polar bear exhibit, breaking ground by this summer. The $8 million project will triple the amount of space the polar bears currently have. It includes upgrades to their habitat and a brand-new public viewing area.

Phase one of the project will include a Polar Bear Transition Center for orphaned or injured cubs and a maternity den, should the resident polar bears mate, said Patrick Lampi, the zoo's executive director.

The center will allow the zoo to hold and care for up to six cubs. The U.S. Fish and Wildlife Service granted the zoo a five-year permit -- the only one issued in the U.S. -- to respond to orphaned polar bear cubs.

"We're very pleased that they entrust us with that," said Lampi.

Zoo officials note an increase in orphan cubs coming from the North Slope. With increased activity in the Arctic and changing sea ice, the zoo wants to be ready, Lampi says.

"We're looking toward the future -- not knowing what's happening on the North Slope, but indications are that the ice will be forcing more bears on land and forcing more interactions with people which unfortunately resort sometimes in more orphans and injuries," Lampi said.

The second phase of the expansion project will double the zoo's capacity for adult polar bears. A braided water stream feature and upgrades to the yard will add to the polar bear habitat. But zoo visitors will also benefit from the expansion. A large, elevated walkway will be constructed to give guests a view of the bears from above.

Phase one is scheduled to begin this summer and expected to be completed by 2015. Construction for phase two of the project is scheduled to start in 2016 and be completed by 2017.

The Alaska Zoo has about $1.4 million raised for the first phase of the project, estimated to total $1.87 million.