The corporate authorities of the Sanitary District, in order to provide whatever funds may be required by it in furnishing to the United States of America without cost, the necessary land, easements and rights of way, in constructing the Calumet-Sag Navigation Project and for payment of expenditures in relocating utilities made necessary by the construction of the Calumet-Sag Navigation Project, all as hereinbefore authorized under Section 8, may issue, in addition to all other bonds heretofore or herein authorized, bonds of the sanitary district in an amount not to exceed $8,000,000 for such purposes without submitting the question of such issuance to the legal voters of such sanitary district for approval and may, at any time hereafter, pass supplemental appropriation ordinances appropriating the proceeds of the sale of the bonds for such purposes; and such bonds shall be issued from time to time only in the amounts as may be required for such purposes.