The board shall have the authority for the purpose of financing and carrying out the provisions of this chapter to issue anticipatory warrants drawn on the county, in denominations of one hundred dollars, five hundred dollars and one thousand dollars, which anticipatory warrants shall draw interest at a rate not exceeding that permitted by chapter 74A; and shall not be a general obligation on the county and be secured only by the special assessment tax levy as herein provided.
Iowa Code § 353.6