(2) The board may provide in the ordinance authorizing such refunding bonds:
(a) For setting aside a sinking or other fund into a special trust fund for payment of the bonds.
(b) For the pledging of taxes and other revenues directly to the payment of the principal of or interest on the bonds or to the sinking fund.
(c) For limitations on subsequent borrowings by the port either in the nature of permanent debt or temporary financing.
(d) For limitations on the amounts of appropriations in subsequent budgets for operating expenses.
(3) A port has all necessary authority to carry out the terms and conditions so included in any such ordinance. The validity of the refunding bonds, however, shall not be dependent upon nor affected by the validity or regularity of the ordinance provisions enumerated in subsection (2) of this section. [Amended by 1971 c.728 §84]