Back in 2011, the two school systems operating in New Orleans made a pledge: Every public school student in the city would be attending classes in a new or refurbished building by 2016. A $1.8 billion settlement from FEMA, plus other sources of revenue, would make it happen.

Now that promise is looking harder to keep. A combination of factors, including rising construction costs and fewer available dollars than expected, have added up to a $330 million gap between what school administrators had planned to build and what they can afford.

While much of the construction spelled out in 2011 is finished or underway, nearly a dozen projects have yet to get off the ground and may now be in doubt. All of which will mean tough, and perhaps politically dicey, decisions about which projects to scrap or scale back.

In an interview this week, Patrick Dobard, who leads the state’s Recovery School District, said he doesn’t plan on dropping the pledge to see every student in a new or refurbished building, but he acknowledged there is a steep funding shortfall to overcome.

“The ball is inside the 20 and we’re close to getting over the goal line,” Dobard said, but he added, “There’s a staunch defense in front of us.”

The plan for rebuilding New Orleans’ schools, many of which were damaged or destroyed in the flooding that followed Hurricane Katrina, has been contentious from the start. Paul Pastorek, serving as state education superintendent at the time, took criticism for building the first schools completed after the storm too big and leaving too few dollars for other projects.

In 2010, FEMA agreed to commit $1.8 billion to help rebuild or renovate the city’s schools, but deciding exactly how to spend that money has been controversial. A first set of revisions to the building plan in 2011 drew a rebuke from business and nonprofit leaders because it included more than $400 million in unfunded projects without any specific plans for filling the gap.

State and local officials went back to the drawing board, found ways to stretch what they had and identified tax credits that could bring in more cash.

Now, though, the gap is back.

One reason is higher construction costs. Dobard said the 2011 construction plan envisioned spending about $210 per square foot; instead, the district has had to spend close to $250 and in some cases more than $300.

On top of that, officials haven’t been able to secure as much money in tax credits as they expected: about $7 million so far, with perhaps another $35 million to $40 million on the way, Dobard said, but not the $80 million originally imagined.

There will probably also be more students to find seats for than anticipated. In 2011, school officials were expecting the student population to hit anywhere from 42,000 to 47,000 students by 2016. Now it’s looking more like 55,000.

Dobard said the balance between elementary and high school students is also shaping up to skew more toward younger students than expected, which could lead the district to scale back the number of high schools in the works.

In all, Dobard said, about 82 percent of the construction plan is either complete or underway, in terms of dollars spent. Put in terms of seats for students, the percentage complete or underway is 77 percent.

Dobard said the district should have more specifics on how to confront the funding gap before the state Board of Elementary and Secondary Education meets in New Orleans next month.

The funding shortfall will also affect projects overseen by the Orleans Parish School Board, which held onto a smaller number of campuses when the Recovery District took over most schools after Katrina, though probably to a lesser extent.

Interim OPSB Superintendent Stan Smith pointed out that the district recently negotiated with the Recovery District to put Bethune Elementary in one of the Recovery District’s buildings, so money that would have gone into Bethune’s existing facility can be redirected elsewhere.

Still, he said, one or two projects now slated as full “renovations” may have to be “stabilizations” instead. “We’re in a sellers’ market, and we’re seeing costs go up,” Smith said.