When CA passes a general obligation bond to fund school construction, how long does it have to use the money?

When CA passed prop 47 in 2002, prop 55 in 2005 and most recently prop 1D in 2006, was there a time limit during which CA would have to spend the funds? Are those funds available to school districts indefinitely (until they’re all spent), or do they have a fixed window to claim the funds before the money goes away? Please help!

Thanks!