Still, while the bridge is a milestone, park managers and scientists acknowledge it’s also only a stepping stone, one piece of a complex multi-billion-dollar overhaul of Everglades plumbing that will take decades to complete.

Just for starters, to move the massive amount of water scientists say is needed to restore the Glades, a lot more bridging will be needed.

The Interior Department, which oversees national parks, drew up blueprints in 2010 calling for an additional 5.5 miles of bridging. The $310 million plan, which would erect four more bridges of varying length along the Trail, has been “authorized” by Congress and is currently being designed.

Salazar, who is stepping down as Interior secretary after championing restoration in 11 visits to the Everglades, said the Obama administration intends to “shake the trees’’ looking for money for the work, with one possible source the hundreds of millions of dollars coming to the state from the settlement of the BP oil spill in the Gulf. But it remains uncertain if a divided Congress dealing with sequester budget cuts will sign off on the proposal.

For now, there’s also not nearly enough water to send south through the Everglades and much of what there is isn’t clean enough for the sensitive Everglades, tainted by too much phosphorus, a nutrient in farm, pasture and yard runoff that is damaging to sensitive Everglades plants. Now, much of it gets diverted down the Caloosahatchee and St. Lucie rivers, where it has triggered fish kills and algae blooms. Florida’s plans to build more storage areas and artificial marshes to absorb the pollution, already delayed by a decade, have been pushed back another decade under the state’s latest $880 million clean-up expansion plan.

Another on-going $1 billion plan to add reservoirs and speed up work on the Central Everglades is on the fast-track – but won’t work without additional bridging on the Trail. Beyond that, there are still unresolved technical questions. Raising water levels in the Everglades could raise ground water levels in surrounding lands, including the flood-prone suburbs of west Miami-Dade, or even divert water away from the county’s major well field and Biscayne Bay.

Still, for every other project to work, raising more of the Tamiami Trail is critical.

“There is no middle ground. Without a fix to this issue, Everglades restoration can’t go anywhere,’’ said Van Lent. “The one-mile bridge got us as far as you can go. Now, you have to do the rest of the road.’’

Environmentalists, park managers and federal officials hope fixing the rest of the road will prove easier than the first mile.

The bridge is the last major piece in the Modified Water Deliveries project, originally approved by Congress in 1989 as part of plan to restore water flows to a newly acquired 107,000-acre section of Everglades National Park. But “Mod Waters,” as it came to be known, became mired by shifts in restoration plans, disputes over flood protection for residents in a rural section once known as the 8.5 Square Mile Area and multiple lawsuits – four of them by the Miccosukee Tribe.

The Tribe, arguing that construction would violate an array of environmental rules and that a bridge was a waste of taxpayer money, eventually won an injunction in 2008 from a federal judge to block the work. The tribe, which did not respond to a request for comment on the new bridge, has long argued that a $17 million plan to clean out the existing culverts would provide faster relief for high water damaging tribal land, tree islands and wildlife north of the Trail.