Simplified: Harrisburg School District plans to add a third middle school and the start of a second high school by 2023, Superintendent Tim Graf said. The district is the fastest-growing in the state, largely due to a growing population in southern Sioux Falls.

How do you build a partial high school?

Start small. The district's proposal is to start with a standalone Freshman Academy building to house the projected increase in the ninth grade class in coming years.

Then, as the district continues to grow, it can add on extra classrooms and facilities like a performing arts center to the new building to eventually have a full-blown second high school.

Where will these schools go?

Both are right on the edge of Sioux Falls city limits.  

The middle school will be near 69th Street and Southeastern Avenue on a plot of land the district has owned for years.

The high school/Freshman Academy will be at the southwest corner of 85th Street and Cliff Avenue on a nearly 80-acre plot of land purchased in December for about $1.7 million, according to Superintendent Tim Graf.

Why now?

Because Harrisburg's school district is growing fast, and for years, that growth has been at the elementary level. As those kids age into middle and high school, there isn't room for them in existing facilities, Graf said.

In 5 years, the district added more than 1,000 students. That's more than a 30 percent increase. And if you look back a decade, student enrollment has doubled, according to district data.

"It's not like a 'Oh this would be cool to do this,'" school board member Mike Knudson said of the new buildings. "This is like, 'We have to have this.'"

What will the schools cost?

About $60 million. That's the budget officials say they need to stick to if they want to keep property taxes in the school district from going up.

What's the timeline?

School board members first need to vote on putting forth a bond referendum (meaning a public vote on whether the district should spend this money). That is expected to happen this month.

Then, an election will likely be set for June. If passed, Graf hopes to have plans finalized over the summer with construction starting this fall.

"We just can't afford to wait," Graf said.