After four years of watching his schools bleed students to Roseland, Santa Rosa City Schools, Bennett Valley and other districts, Bellevue School District Superintendent Tony Roehrick did something drastic.

He began telling incoming kindergarten families they couldn't leave the district, which has four schools teaching 1,700 students from south of the Sonoma County Fairgrounds to west Santa Rosa near Elsie Allen High School.

"Unless parents have a really strong, legitimate reason for having students attend a different school at kindergarten, we are denying those," he said. "All we are asking is that you just consider us and not dismiss us out of hand."

Bellevue pulls from attendance boundaries in which 23 percent of youths under 18 are white and yet only 9 percent of the district's students are white. Nine out of 10 students qualify for free or reduced-price lunches.

"The ones that tend to go to Bennett Valley and Rincon Valley for us tend to be white, more middle class, higher socioeconomic," he said. "I don't know if you call it white flight or what. It certainly is in our more affluent neighborhood where we are less represented by the kids who attend our schools."

Bellevue loses 40 percent of the students who live within its district boundaries every year. In 2009-10, 128 students left for Roseland, another 114 went to Bennett Valley and 109 went to Santa Rosa City Schools. An additional 293 went to 13 other districts.

"That is the loss of an elementary school," said Roehrick, superintendent for the past five years.

To stop the flight, district officials unveiled a dramatic change in policy for the current school year: blanket denial to all families seeking to attend kindergarten outside the district.

Parents could appeal, and some were successful. And the district has since tweaked the rule, allowing younger students to follow already-transferred older siblings, as well as permitting movement for work and day care needs, Roehrick said.

The policy cannot be enforced in Bellevue's grades first through sixth because the district is in federal sanctions under the No Child Left Behind law for failing to meet academic benchmarks.

But because kindergarten is optional in California, Roehrick said the district has the freedom to tell families they must enroll within the district -- unless they choose a charter or private school, or skip kindergarten altogether.

The policy, which runs counter to school choice policies in place throughout Santa Rosa and Sonoma County, appears to have paid off.

Bellevue's current-year kindergarten enrollment is 269 students, up dramatically from 226 in 2010-11.

"What we are trying to do is have parents give us a second look instead of almost by reflex say, 'I'm going to another school,' " Roehrick said.

Following Bellevue's example, some Sonoma County districts are starting to have second thoughts about letting their students automatically leave for neighboring districts.

"Given the state of school districts and the economy and everything going on, districts are trying to find ways to retain students and their enrollment is certainly becoming a bigger issue," said Loren Soukup, an attorney with School and College Legal Services who worked with Bellevue on its transfer policy.

"We do see districts trying to find creative ways to keep their kids and stay legal," she said.