LAKEWOOD — The defeat of two ballot measures that would have raised more than half a billion dollars for the Jefferson County School District has claimed its first casualties, with district officials saying that badly needed classroom capacity in fast-growing northwest Arvada may go on the chopping block.

Specifically, construction of Leyden Rock Elementary School will be delayed for the foreseeable future while expansion plans at Three Creeks K-8 in the Candelas neighborhood, set to debut in 2017, also are on hold.

That’s just the start of what the district, the second-largest in Colorado, warns could be coming in the wake of voter rejecting Issue 3A, a $33 million mill levy override, and Issue 3B, a $535 million bond measure.