I don't know when it is happening but my neighbor is an architect whose firm has already been looking at designing the 3rd high school. It's not just theoretical.
I'm looking thru the 62-page presentation from most recent school board meeting.
Interesting facts
*the largest class in Ankeny schools right now is 9th grade
*Currently 962 seniors and 987 first graders
*Total enrollment up 312 from 3 yrs ago
None of these suggest massive growth of 2010s is continuing.
Demographer now predicting 800 new students in next 5 years (160/yr). A five year span a decade ago saw growth of 2100 (420/yr) a decade ago.
Three Northside elementary buildings will be over capacity in 23-24; a new building on north side is currently being built to relieve that. The Northside 6-7 building will exceed capacity in 2025-26 but district wide won't clear 6-7 capacity until 2029-30.
District wide HS capacity is 3700, demographer projects 3296 in the 2032-33 school year.
My conclusion - Ankeny will not have a third high school within the next decade.