With enough perspective, it’s easy to find the Bonnet Carre floodgates even without knowing exactly where to look; just see where beige tumbles into emerald.

From above, the sand-colored Mississippi rolls across the floodplain into the dark green Lake Pontchartrain. For conservationists, it’s a reminder of all the sediment being shunted off into the lake that could be used to rebuild Louisiana’s coast.

Members of Restore the Mississippi River Delta flew journalists over south Louisiana Friday to emphasize their point. The plume of the silty Mississippi is visible from a low-flying sea plane.

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John Lopez, the Lake Pontchartrain Basin Foundation’s coastal sustainability director, points out another area of contrasting colors – the east and west bank of the Mississippi about 40 miles downstream of New Orleans.

Here, by the Mardi Gras Pass, the east bank levee was torn out in 1926, Lopez explains. From above, the water looks full of coffee grounds which is actually the sediment that will rebuild the wetlands. Where the river and the marshes mingle, verdant new land is forming.

The other bank looks sickly in comparison – full of open water where much of the land is just the tops of spoil banks left over when oil and gas companies dug navigational canals through the wetlands. Gone are the marshes and oyster beds, Lopez points out.

All the ports and plants on the west bank mean that breaking down the levee is inconceivable in the way that worked on the other side of the river nearly a hundred years ago. But the sediment flowing across the Bonnet Carre is reason to be optimistic, Lopez said; it shows there is land-building potential in the Mississippi, if only it can be harnassed.

That’s why the Restore group is taking the chance to remind policy makers to shepherd through the mid-Barataria diversion canal and other coastal projects.

“We’re in the broad business of trying to hurry this stuff up. … We understand these things do take time, and we want them done right, but we don’t want them to take a day longer than necessary,” said Steve, Cochran, the Environmental Defense Fund administrator who directs the Restore the Mississippi River Delta Coalition.

Mid-Barataria would redirect part of the Mississippi through the west bank wetlands south of New Orleans to rebuild the coast. However, it requires the blessing of several groups including the Army Corps of Engineers, the Environmental Protection Agency and the Department of the Interior. Officially, permitting is scheduled to take through 2022, and construction will likely last another four or five years, Cochran said.

In the waning days of the Obama administration, the federal government put the project on the fast track, and the Trump administration has vowed to complete federal permits by the end of next year. But the conservation groups are still making noise to make sure the regulators keep those promises.

In the past, federal agencies reviewed projects one at a time, but Cochran wants them all to consider Mid-Barataria simultaneously so the project doesn’t get held up.

It’s important to move quickly, because even once the canal is built, it will take five to ten years for it to operate at full capacity. Throwing open the gates right away would shock the wetlands and kill the plants and animals that coastal scientists are trying to preserve, said Natalie Peyronnin, the Environmental Defense Fund’s director of science policy for the Mississippi River delta.

“We definitely need to accelerate the (permitting) schedule. … We’re up against a fight against time,” she said.

The canal will offer some new options, like flooding the wetlands during the winter instead of waiting for spring. When plants and animals are more dormant, they may be better able to tolerate an influx of fresh river water, which could speed up restoration, Peyronnin said.

While the emphasis is on mid-Barataria, the environmental groups are also interested in building the mid-Breton diversion on the east bank upstream of the Mardi Gras Pass to rebuild wetlands on that side of the river where the levee still exists.

There is precedent for this type of work, Lopez said. As far back as 1992, diversions have been dug to refresh areas like Caenervon, where wetlands were cleared to grow sugarcane and watermelons. Canals were dug there and around Davis Pond to capture the Mississippi River primarily to reintroduce fresh water, but sediment made its way into the areas too and helped rebuild areas that had converted to open water, Lopez said.

Now, with a focus on sediment, he hopes to redirect part of the river into the marshes beyond the west bank via Mid-Barataria.

Follow Steve Hardy on Twitter, @SteveRHardy.