The District's charter school enrollment nearly doubled this year to 6,721 students on 29 campuses, according to preliminary figures released yesterday, meaning that nearly one in 11 youngsters has left the traditional public school system to join the city's three-year-old charter movement.

Charter advocates say they know of no other jurisdiction where charter schools have so quickly drawn such a significant percentage of the public school population.

"We're going to see a lot of eyes turning here," said Jeanne Allen, president of the Washington-based Center for Education Reform, which tracks publicly funded charter schools nationwide.

Because both traditional and charter schools receive funds based on enrollment, the growth means an increased flow of tax dollars from the regular public school system to charters -- which has been a longtime concern of charter opponents.

Shirley Monastra, executive director of the D.C. Public Charter School Resource Center, predicted that the independently run charter schools could enroll one in four D.C. students by 2005.

She and other proponents said that despite a few well-publicized problems with start-up schools, charters have attracted support because they offer a unique laboratory.

"We can prove something here -- that charter schools are an integral part of serious school reform," Monastra said.

The enrollment figure released yesterday is based on tallies reported by the individual charter schools as part of a count taken in all public schools. The figure will be audited this month and reported to Congress as required by law.

The District's regular public school system enrolled nearly 72,000 students last year and will report a current count for its 146 schools after the audit. Demographers have questioned the figures from the traditional school system despite audits confirming them. Monastra, whose resource center reported the charter populations, emphasized that the numbers are preliminary but said that they seem solid and are slightly under the charter schools' full capacity.

The rapid enrollment growth reflects the high demand for alternatives to the city's many struggling schools and what Allen termed the "friendliness" of the D.C. charter law passed by Congress in 1996. It places few restrictions on charter schools and allows the creation of up to 20 a year.

Virginia has authorized the creation of charter schools but has yet to open one. In Maryland, Baltimore has several charters, and Montgomery County is starting to review applications.

Most D.C. charter schools have won praise from parents, but a few have floundered, illustrating the risks inherent in the movement and generating a barrage of bad publicity.

Two schools chartered by the elected D.C. Board of Education -- one of two panels Congress authorized to issue charters -- have been shut down because of financial and management difficulties. Another school, Kwame Nkmurah International, opened last month without full approval from the elected board after waiting weeks for the panel to take final action.

Its approximately 270 students, who were not included in the enrollment count, remain in limbo while administrators and the school board wrangle over whether the school can continue.

Charter watchdogs say the other panel authorized to create such schools, the appointed Public Charter School Board, monitors its schools much more closely and that, as a result, they have flourished.

The elected school board was stripped of its authority over the regular school system in 1996 and since then has had few responsibilities other than monitoring charters. Monastra said the panel's shortcomings are hurting the charter movement nationwide.

Members of the school board "need to either do their job and do it well or get out of the business of chartering schools," Monastra said. "It's critical that they . . . cross all the t's and dot all the i's so they cannot inadvertently implode this charter school possibility."

The board has hired a strong charter school director, and its charter school subcommittee has logged long hours weighing applications and progress reports. But advocates say more qualified staff members are needed. And some board members acknowledge privately that their colleagues refuse to take an interest in charter schools.

The elected board is slated to regain authority over the city's public school system next June, and some charter advocates say this will create a conflict of interest as traditional schools and charters increasingly vie for students.

That competition was visible last month in correspondence sent by Superintendent Arlene Ackerman to parents of Kwame Nkmurah students.

"We understand the importance of uninterrupted class time and want to offer your children an opportunity to join the D.C. Public School family," Ackerman wrote in a letter accompanying a sternly worded warning that the school might be shut down. Her letter invited parents to "learn about the progressive educational programs" at their neighborhood schools.