SILVERADO – Deby Rice and Mary Gregrow stood looking down at the Agua Chinon creek as a cool ocean breeze whipped up through the surrounding canyon.

The South Orange County residents and Irvine Ranch Conservancy employees were among the first group to take in a breathtaking view of Limestone Canyon, also known as Orange County’s mini Grand Canyon, on the East Sinks Viewing Deck.

“It’s hidden when you’re driving around,” said Gregrow, a human resources and payroll adminstrator with the conservancy, “but it’s amazing that, within minutes, you can be out here and feel like you’re on vacation.”

Orange County 3rd District Supervisor Todd Spitzer, O.C. Parks and the Irvine Ranch Conservancy held a ribbon-cutting ceremony Tuesday morning for the viewing deck, the second installed in Limestone Canyon, in front of a small crowd of hikers, mountain bikers and equestrians.

The newly opened East Sinks Viewing Deck provides a panoramic view of the iconic geological formation known as The Sinks and overlooks Agua Chinon, the headwaters for the San Diego Creek that feeds into Newport Bay. The deck overlooks Orange County wilderness and the city of Irvine and, on clear days, may provide a view of Catalina Island.

The structure is an 8-foot by 24-foot low-raised platform constructed from plantation cedar and recycled plastic caps that can hold up to 20 visitors.

O.C. Parks funded the project, which was constructed over a four-week period by Irvine Ranch Conservancy staff. Cost for the materials was about $10,000.

Installation of the deck and the short trail leading up to it took four days.

“The decks provide safety for people who like to get close,” said Michael O’Connell, executive director of the conservancy. “This is a great place to get photos and now we have a good way to positively manage visitor use.”

As part of the ceremony, Spitzer released a young hawk, which was rehabilitated by the Orange County Bird and Prey Rescue Center after a leg injury, the result of crashing into a window.

The second viewing deck is another step in the continued efforts by the three entities to balance visitor interaction with the preservation of the natural habitat.

“This is a gem in Orange County,” Spitzer said. “We get to preserve this forever. It will be a place that generations to come will enjoy.”

The West Sinks Viewing Deck was opened in March 2011 as an effort to allow hikers, mountain bikers and equestrians to enjoy the view without causing damage to the surrounding habitat.

O’Connell said the state of the surrounding habitat improved as a result.

Stacy Blackwood, director of O.C. Parks, added that the decks will provide learning and interpretive opportunities for educational programs.

Both decks are approximately four miles from the Portola and Augustine Staging areas and are about one mile apart. Blackwood said O.C. Parks and the Irvine Ranch Conservancy are taking steps to form shorter trails to make it easier for families to make it up to the decks.

“The view is fantastic,” said Rice, a science and stewardship assistant for the conservancy. “I’m glad they built a second deck. Most people don’t know about this area, but it’s great to come up and hike.”

Contact the writer: npercy@ocregister.com