It’s no surprise Gov. Jeff Landry ordered the Coastal Protection and Restoration Authority to conduct a complete review of the Mid-Barataria Sediment Diversion.

After all, his smooth road to the governorship was paved in part with strong support from commercial fishers — the project’s loudest and most enduring opponents.

Those fishers rightly fear the loss of current fishing grounds to a flood of fresh water and sediment from the river, so they have questions. But so do some others — especially about the price, which has spiraled from a 2012 estimate of about $374 million to $3 billion.

I first went to the CPRA for answers but was told any questions about “this subject” had to go through the governor’s office.

That brought no reply, so I went to two respected Ph.Ds with long records of researching wetlands and our coastal crisis, Donald Boesch and Natalie Snider. Here’s a paraphrase of their replies.

Will this kill fishing businesses, and is that fair?

There will be temporary losses, and some fishers will have to relocate. But the plan now includes $305 million to help them relocate and learn new ways of harvesting the same species.

More importantly, the long-term viability of fishing depends on the acres of wetlands we can maintain, and that depends on reconnecting the Mississippi River to the coast.

What about dredge-and-fill operations that bring in less river water and are much less expensive?

That’s still the largest part of the master plan. But that becomes too costly because of the need to redo these operations in about 20 years due to subsidence, and as the distance to sediment supplies lengthens.

Is this a reasonable cost given the projected benefits? We’re now talking about $225,000 per acre of wetlands created.

That was unexpected, but much of that cost involved years of research and computer modeling to fill in large holes in knowledge needed to make projections of what could be accomplished.

And that $225,000 figure is based on rebuilding about 21-25 square miles. Our research shows the CPRA used sea level rise projections almost four times higher than those used by the International Panel on Climate Change. Using the IPCC figure, the projection shows twice as many wetlands by 2070. So that $225,000 is cut in half.

Further, CPRA studies show that diversions will help prolong the life of wetlands rebuilt with dredge-and-fill. So they will make those more cost-effective.

Still expensive, but everything learned from this process will make future diversions much less expensive.

Would it be wiser to use the $3 billion to build levees to protect communities?

We’re not against levees to protect critical infrastructure, but most of this money cannot legally be diverted. The majority comes from civil and criminal penalties resulting from the Deepwater Horizon disaster granted specifically for this project and/or rebuilding barrier islands.

And canceling the project could mean the state would have to repay those billions, including millions owed the private contractors that already signed agreements.

Since this will be the first controlled engineered diversion ever built, isn’t this really a big, expensive experiment? Isn’t this too risky?

First, we know this works because new land is still being built on the Atchafalaya River’s delta. And, for that matter, there’s land being built at a natural crevasse downriver now called Neptune Pass.

Yes, there are uncertainties. But we know this landscape is subsiding and sea level rise is accelerating due to climate change.

Obviously, the key to any long-term sustainability on any coast will be reducing the emissions that cause warming and sea level rise. That is a long-term project that, frankly, the state and world must do better at.

But subsidence here will continue regardless. And the only tool we have to deal with that is the sediment from the river.

Maybe it turns out this isn’t the most efficient way. But we need to get started and learn the best way to reconnect the river to our coast.

Bob Marshall, a Pulitzer Prize-winning Louisiana environmental journalist, can be reached at bmarshallenviro@gmail.com, and followed on Twitter @BMarshallEnviro.