The beach is back.

Beginning Saturday Muir Beach will be once again open to the public after undergoing a six-month, $4 million revamp.

“When you drive in now you see the ocean on the horizon, you feel you are being welcomed to the beach,” said Sharon Farrell, associate director of park projects with the Golden Gate Parks Conservancy, as she looked over the work on Friday. “The vistas are fantastic.”

In addition to the view, visitors will see a new parking lot, an elongated 440-foot bridge that sits over a wetlands and new restrooms replacing the old port-a-potties. An interpretive exhibit that allows visitors to pour water in a model to show the flow through the local watershed is also part of the redevelopment.

Eventually picnic areas, complete with grills, will be placed near large stairs that have been imprinted with kelp, shells and sea rocks. That locale is wheelchair accessible, as is the beach entryway, which has been fitted with a special mat. A path to the beach has been moved out of dunes and aligned with the Coastal Trail to protect habitat.

The area, operated by the Golden Gate National Recreation Area, sees about 260,000 annual visitors.

The beach’s old parking lot — which acted as a dam to natural water flow — was the target of much of the work. Its removal increases the flood plain from 50 to 450 feet and reintroduces a more natural flow of water to the area. The lot change also will serve to reduce some of the flooding the community of Muir Beach sees during moderate rains, officials said.

An extended footbridge to the beach travels through the flood plain, affording visitors an opportunity to observe the dynamics of wetlands up close. Those areas are now planted with arroyo willow and dogwood, which will take some time to grow in.

“You really feel like you are over a flood plain now, part of a natural system,” Farrell said.

The work — about half of it funded by Cosco Busan settlement money — should encourage the return of fish and other critters, including endangered coho salmon, as the mouth of the Redwood Creek watershed opens to allow a flow that was last seen a century ago.

“It opens up the mouth of the Redwood Creek,” said Alex Picavet, spokeswoman for the National Park Service. “It’s the creek that goes to Muir Woods, where coho salmon and steelhead go.”

This fourth phase of work at the site is part of a larger $13 million project to restore the area that was once known as the Big Lagoon, once an integral part of the ecosystem at Muir Beach. In the 1950s, the 12-acre freshwater lagoon — which had another 13 acres of surrounding wetlands — started to disappear, choked by fill and levees put in by ranchers so the area could be used for cattle and dairies. The parking lot, built in the 1980s for access to Muir Beach, caused more damage.

Now that damage is being undone, project backers say.

Kris Martinovich of Pacifica was hiking to the beach Friday with a group of friends and liked what she saw.

“It looks like the footbridge will let the water come through more naturally,” she said. “It all looks more natural now.”

Contact Mark Prado via email at mprado@marinij.com