NATIONAL CITY, Calif. - A new collaborative project is giving a part of the San Diego Bay a new lease on life.

It's called the D Street Fill, but it's really a salt marsh sanctuary for hundreds of animal and plant species. It's located along the bay between National City and Chula Vista.

Andy Yuen with the U.S. Fish & Wildlife Service is a bit excited, and he told 10News, "It really is a major milestone. This is for the first time in 60 years, it is receiving tides again."

The U.S. Fish & Wildlife Service is working with San Diego Gas & Electric to restore the area to the way it was in the 1920s. By the 1950s, the salt marsh was filled with sand and dirt dredged from San Diego Bay.

SDG&E is behind the $5 million mitigation project because it is building a new power substation just south of Chula Vista's ambitious Bayfront Master Plan. That plan started with the 2013 implosion of the infamous South Bay Power Plant. SDG&E needed to move an older substation when the power plant was demolished. They needed to mitigate for the new substation.

"It's part of the master plan," said SDG&E spokeswoman Allison Torres. "It's part of the restoration efforts that we are overseeing."

SDG&E worked with the U.S. Fish & Wildlife Service and the California Coastal Commission for years on plans to restore the salt marsh.

"It's so impressive," said Torres.

"This was a very complicated project," said Yuen. "[Workers] moved about 125,000 cubic yards of material and created this salt marsh basin."

Crews are still planting more than 15,000 plants. Water from the bay returned to the area for the first time in 60 years.

Yuen said the salt marsh is a perfect habitat for the endangered light-footed ridgeways rail.

The sand that was removed from the area was deposited on an elevated area nearby which benefits another endangered bird: the California least tern.

"It was a two-for-one deal," said Yuen.