(a) Bonds issued under this subchapter must be secured by a pledge of and be payable from all or a designated part of the revenue from the improvement or facility for which the bonds are issued, as provided in the order authorizing the bonds.
(b) The pledge securing the bonds is inferior to any previous pledge of the revenue for the payment of revenue bonds or revenue refunding bonds that are outstanding.
(c) A county that leases a facility described by Section 1477.302 as lessee may pledge all or part of the revenue from the facility to the lease payments.