In the years before floodwaters killed more than two dozen people at Camp Mystic in Texas, regulators approved a series of appeals that removed many of the camp’s buildings from official federal flood zones, records show.

Flood maps developed by the Federal Emergency Management Agency in 2011 had placed much of the camp within a 100-year flood zone, an area considered to be at high risk of flooding. Camp Mystic successfully challenged those designations, which would limit renovation projects and require flood insurance, citing elevation calculations of a series of buildings that allowed them to be exempted from the federal restrictions.

Sarah Pralle, an associate professor at Syracuse University who has researched federal flood mapping, said she found the exemptions granted to Camp Mystic, a girls’ camp on the Guadalupe River near Hunt, to be “perplexing.” Some of the buildings were still very close to expected flood elevations, she said.

“I think it’s extremely troubling that it’s a camp for children,” Ms. Pralle said. “You’d think you want to be extra cautious — that you’d go beyond the minimum of what’s required for flood protection.”

It was unclear from the federal records precisely which buildings were removed from the flood maps, and the camp’s more detailed application for removal, which was first reported by The Associated Press, was not available. FEMA’s official flood maps show that some of the camp’s cabins were within a “floodway,” a particularly hazardous area where dangerous floodwaters would be expected to flow. Other cabins were within a broader zone that would also be expected to flood once every 100 years. Those maps have not been modified to incorporate Camp Mystic’s written appeals.

Some of the buildings included in Camp Mystic’s appeals were listed as having an elevation more than 10 feet higher than the 100-year flood level, a measure of the probability of a major flood occurring. But others were much closer: In a 2013 document about removing buildings from the flood zone, six of the 15 buildings identified were described as being within three feet of the 100-year elevation.