New elementary schools are opening this month in two of the fastest-growing cities in Iowa — Tiffin and North Liberty.In Tiffin, Clear Creek Amana Community School District’s Oak Hill Elementary will welcome fourth- and fifth-graders on Monday. Christine Grant Elementary in North Liberty, part of the Iowa City Community School District, opens Friday to grades kindergarten through six.Construction of both buildings was funded by property-tax backed bonds passed in 2017 in each district.Enrollment in both the Clear Creek Amana and the Iowa City school districts has skyrocketed in recent years.Clear Creek Amana Community School District, which covers booming areas like Tiffin and parts of Coralville, has grown by nearly 1,000 students in the last decade, state data show.Expected to cost a total of about $19 million, Oak Hill Elementary is expected to relieve overcrowding at other metro area schools, Tiffin and North Bend elementary schools.The Iowa City district, the fifth-biggest in the state, has grown by 2,700 students in 10 years according to state data.Construction of Grant Elementary, with a final cost of $18.5 million, was part of a massive building frenzy in the district this summer.