Bonds issued under this chapter shall be payable exclusively from the revenues of the Department and shall contain a statement on their face that the state shall not be obligated to pay the bonds or the interest thereon except from such revenues, and that the faith and credit of the State are not pledged to the payment of the principal or interest on such bonds. The issuance of bonds under this chapter shall not directly or indirectly or contingently obligate the State to levy or pledge any form of taxation whatever therefor or to make any appropriation for their payment.