MINNEAPOLIS — New figures from the 2010 census show a small surge of young children in Minnesota, and look no further than the town of Waconia near Minneapolis for evidence of how that could change school districts throughout the state in the next few years.

“For us, it’s not a question of if growth will happen, but when the growth will happen,” said Waconia Superintendent Nancy Rajanen, whose district has called for a referendum May 17 on issuing $8 million in bonds to buy land for two new schools.

The 2010 census found that 9 percent of Waconia’s population of 10,697 was younger than 5. Nearly 19 percent of Waconia’s residents were 9 years old or younger. This has driven the district to steadily add teachers, while struggling to find space for its younger students.

The two elementary schools are crowded, so the district is looking to convert some common areas into classrooms, Rajanen said. Pre-kindergarten classes were moved out of the elementary schools to converted space in the administration building in a business park.

“It has certainly made us very creative in terms of our space,” Rajanen said.

The U.S. Census Bureau reported Wednesday evening that there were more than 355,000 children under age 5 in Minnesota in 2010, almost 26,000 more youngsters than there were in 2000. It also found there were more children age 9 and under than there were children 10 to 19, a flip from 2000 when there were 64,000 more older children than younger ones.

State Demographer Tom Gillaspy said the jump in young children signals a turnaround in nearly a decade of declining enrollment in the state’s public schools and could mean significant changes on how districts operate.

“We’re going to see a continued increase in elementary enrollments,” Gillaspy said.

He said the population bubble is being driven by people moving into Minnesota from other states and countries.

“People who move long distances and cross significant boundaries, as many job seekers do, those are young people,” Gillaspy said. “It is a statistical fact that people in the 20s are more likely to have babies than people in the 70s and 80s.”

And he said he expected births would continue to increase as the economy improves. “Births do lag in recessions,” Gillaspy said.

Schools have been planning for the influx of young children, said Charles Kyte, executive director of the Minnesota Association of School Administrators. “You have to analyze the numbers carefully,” he said.

That analysis will lead administrators in the coming years to make decisions on hiring and firing teachers and opening and closing existing schools and, possibly, going to the voters for the money to build schools for children who aren’t yet born.

“You may have to be laying off secondary teachers to hire more elementary teachers,” he said. “When there’s plenty of money you can carry some extra staff here and there, but when times are tight you have to be tight.”

Still, he said, too many young kids are better than too few. “Our business is kids and the more the merrier — even though sometimes you have to scratch your head and wonder where you are going to put them,” Kyte said.

Bob Porter, a finance specialist with the Minnesota Department of Education, said the department projects that public school enrollment will increase by about 31,000 — from about 822,000 in 2010 to about 853,000 in 2015.

That will include a jump from about 365,000 in grades 1-6 in 2010 to about 396,000 in the same grades in 2015. Enrollment in grades 7-12 will hold about steady until 2015 at about 390,000.

“Elementary is growing significantly,” Porter said. The projections don’t include kindergarten.

The Education Department isn’t predicting uniform growth but instead expects the increase to concentrate around the wealthy, mostly white areas west of the Twin Cities such as Waconia and in rural population centers with youthful immigrant communities including Austin and Worthington.

In Worthington, Superintendent John Landgaard said, “We are actually seeing it in our elementary now.”

Over the past 20 years, waves of immigrants have moved into the area to work in the meatpacking plants. They have put down roots, started families and made educating their children a priority, he said.

The new census figures show 9.2 percent, or 1,178, of the city’s population of 12,764 is less than 5 years old. The median age in Worthington is 33.5, less than state’s median age of 37.4.

Landgaard said children of immigrants were changing the district. Eight years ago, he said, the student population was about 65 percent white; now it’s about 38 percent white and even lower in the elementary school.

With even more students on the horizon, Landgaard has been wondering when the district will have to expand its 10-year-old elementary school. When it opened, the school was the largest in the state with the capacity for 1,100 students, he said. Now it could be full in three years. Or sooner.

“There was never a vision that would happen in this community,” Landgaard said.