HUNTINGTON BEACH, Calif., Aug. 24 (AP) — The ocean flowed into a historic wetland on Thursday for the first time in more than a century, after bulldozers peeled back the last layer of an earthen dam.
Environmentalists who had worked for 30 years to restore the Bolsa Chica area, a fragile ecosystem that has been used as an oil field for decades, cheered and sipped Champagne as the salty water poured into part of the basin, an expanse of 387 acres.
The event concluded a two-year project that cost more than $100 million and included the shunting of part of the Pacific Coast Highway onto an overpass.
Officials said it would take at least six hours for the ocean water to fill the basin. The area had been separated from the ocean for 107 years.
Eight state and federal agencies were involved in the project, and all called it the largest and most ambitious restoration of coastal wetlands in the history of California, where 95 percent of saltwater marshes have been given over to development.
The Bolsa Chica wetlands project is at the fore of a new and evolving science, said Shirley S. Dettloff, a leader of the conservation group Amigos de Bolsa Chica.
“Not many wetlands have been restored in the world, especially in an oil field,” Ms. Dettloff said. “Even we locals sometimes forget that this was the second-largest functioning oil field in the state of California for years, since the 1930’s.”
The degraded wetlands are already home to 200 species of birds. Tidal flows and ebbs will fill and drain the basin twice a day, restoring a natural rhythm that scientists say should replenish the ecosystem and could attract more species.
The area was connected to the ocean until 1899, when a duck-hunting club diked ponds to make it easier to attract the birds.
In 1997 the state bought 880 acres of the wetlands for $25 million, and that parcel was added to 300 acres that Signal Landmark, a developer based in Irvine, gave to the state for wetlands preservation in 1973.
The restoration was partly financed by the Ports of Los Angeles and Long Beach to make up for marine areas destroyed in their expansion. Bond issues approved by voters provided the rest of the money.