It was touted as a triumph of modern engineering when it opened in 1928, a road across the once-impassable Everglades that took 2.6 million sticks of dynamite and 13 years to construct.

On Tuesday, U.S. Interior Secretary Ken Salazar led a celebration of a long-awaited, different sign of progress on Tamiami Trial: the completion of a one-mile-long bridge designed to begin healing the ecological wounds inflicted by a road that has blocked the flow of the Everglades for nearly 90 years.

“It truly is a crown jewel of an achievement,” said Salazar, who snipped a red-ribbon, then took a ceremonial first drive across the span in a hybrid SUV.

The $81 million bridge, scheduled to open to daily traffic in a few weeks, ranks among the most significant Everglades projects to date. It sets the stage for the first breach later this year of a historic road that has been far more than just a lime rock-and-asphalt barrier to reviving the shrunken, struggling River of Grass. The effort to get more water under the bumpy two-lane black top, originally launched by Congress in 1989, has encapsulated all the numbing delays, doubts and disputes that have dogged the broader plans to restore the Everglades.

The bridge took four years to build — but it was a two-decade battle to simply get it started.

“It’s a day that a lot of folks thought they maybe would never see,’’ said Julie Hill-Gabriel, Everglades policy coordinator for Audubon of Florida. In all, about 200 environmentalists, federal officials, park managers and rangers came out to mark the milestone and take in a new postcard vista. For the first time, motorists can view vast, bird-dotted marshes past the L-29 levee to the north and a tangled jungle lining the Trail to the south.

By itself, the bridge won’t initially make much of a difference to the health of the Everglades – at least until crews later this year remove the old road bed it replaces just a few miles west of Krome Avenue, which will boost current water flows by as much as 15 percent. When the project is completed by raising and reinforcing about 10 miles of the adjacent Trail to handle higher water levels, peak rainy season water flows could nearly double compared to the volume that passes through 19 culverts built under the old road.

That should provide some relief to one of the driest swaths of the Everglades fed by the Shark River Slough, once a major artery of life-giving water. The Trail, along with levees and drainage canals built in the 1960s, choked water flow to a fifth of its historic volume and profoundly altered the landscape, killing off marsh plants and driving away wildlife, with wading birds dropping as much as 90 percent in the park. The ripple effects extended down to a too-salty Florida Bay plagued by sea-grass die-offs and algae blooms.

“The big story is that water levels in the wetlands can go up and that’s a very good thing,’’ said Tom Van Lent, senior scientist for the Everglades Foundation. Re-establishing the broad “sheet flow” of the River of Grass – rather than gushing water through narrow culverts – also will start to help recreate natural conditions that shaped wildlife patterns and the “ridge and slough” geography that defines the Everglades marsh, he said.

“Besides just getting water across the road, there is a lot of stuff in that water: fish, turtles, nutrients, sediments,’’ Van Lent said. “Anything that is in that water needs to get to the other side of the road.”