Bonds issued under this part shall contain a recital on the face thereof that the payment or redemption of the bonds and the payment of interest thereon is secured by a first and direct charge and lien upon the revenues of any nature whatever received from the operation of the Central Valley Project for the construction of which the bonds are issued and that neither the payment of the principal or any part thereof or any interest thereon constitutes a debt, liability, or obligation of the State of California.