The District’s traditional public school system is in danger of shrinking significantly unless officials make changes that persuade parents to stop fleeing to public charter schools, D.C. Council members said Wednesday.

“I believe we are within a year or two of hitting an irreversible tipping point,” said David Catania (I-At Large), who chairs the council’s Education Committee, during a hearing on Chancellor Kaya Henderson’s plan to close 15 under-enrolled city schools.

“If we don’t become very serious about marketing and competing” with charter schools, Catania said, “traditional public schools, as we know them, will become a thing of the past.”

Charter schools have grown quickly in the District during the past 15 years and now enroll more than 40 percent of the city’s public school students, leaving the traditional school system with half-empty buildings in many neighborhoods — and something of an existential crisis.

“On the one hand, we all support high-performing charters, and we support choice for our families,” Henderson said. “But at the same time, we want [the school system] to be robust and to provide everything under the sun.”

Henderson says that closing some small schools will allow her to redirect resources from administration and maintenance to teaching and learning, creating the kind of academic offerings — such as art and music programs, modern libraries and elementary-school foreign language classes — that will attract families.

But on Wednesday, the chancellor offered few details about how she intends to redirect savings to strengthen schools. Such specifics won’t be available until school budgets are determined for the 2013-14 school year, she said.

Schools officials said they expect the closings to save $8.5 million annually, a little more than 1 percent of the system’s total $800 million budget. But critics of the chancellor’s plan question whether the system will save even that much, particularly given the costs of mothballing school buildings, including moving and storing furniture and materials.

Some council members and activists fear that closing traditional public schools will push students into charters, leading to further enrollment losses and future closures. Previous closures have not resulted in demonstrably stronger schools, increased enrollment or leaps in student achievement, they say.

“At best, under-enrollment is a symptom of an underlying disease of inattention and neglect,” said council member Yvette M. Alexander (D-Ward 7), whose ward is home to four of the 15 schools slated to close. “Long-standing neglect should not be used as a justification to close schools and shift the problem without first adequately addressing the root cause.”

When the city shuttered 23 schools in 2008, students from the closed schools were more than twice as likely to enroll in a charter school as students from other schools. This time, 2,600 students are to be displaced, and Catania asked Henderson to explain how she would ensure that they wouldn’t leave the system.

“You’re absolutely right in that many charter schools, because of their proficiency rates, offer, at least on the surface, a better opportunity,” Henderson said. “We’re going to have to work really hard.”

Henderson said she would submit a transition plan to the council by Feb. 15.

The hearing was Henderson’s first appearance before the Education Committee, constituted this month to bring new focus to oversight of city schools. Education had been handled since 2007 by the council’s Committee of the Whole, a forum in which other issues often overshadowed the subject.

“We have been missing in action for six years,” Catania said. A key committee priority will be helping establish a comprehensive plan for the coexistence of charter and public schools, he said.

While council members focused on avoiding future school closures, activists announced Wednesday that they plan to challenge in court the latest round of closings. They say the closures disproportionately affect African American children and students with disabilities.

Black students make up 72 percent of the school system’s total enrollment but account for 93 percent of the students affected by the closures, said Mary Levy, a longtime school system watchdog.

“Folks are losing access to walkable schools, to public resources. What we feel it is about is pushing low-income and moderate income people of color out of the District,” said Daniel del Pielago, of the community group Empower DC, which has called for a moratorium on school closures.

Johnny Barnes, a lawyer who is leading the legal challenge with Empower DC, said he plans to file a complaint with the Office of Human Rights, which could force the school system to share information about how school-closing decisions were made. If the school system fails to respond to the group’s concerns within 30 days, Barnes said he will sue the city for violating a number of local and federal anti-discrimination laws.

“The people who live in Anacostia have the same right to an education as the people who live on Albemarle,” said Barnes, who went on to invoke Democratic Mayor Vincent Gray’s “One City” motto. “You can’t have one city if you don’t have one standard.”