(a) At the time general obligation bonds are issued by the district under Section 1004.251, the board shall impose an ad valorem tax in an amount sufficient to create an interest and sinking fund to pay the principal of and interest on the bonds as the bonds mature.
(b) The tax required by this section together with any other tax the district imposes in any year may not exceed the limit approved by the voters at the election authorizing the imposition of taxes.