The county board may, at the time the next levy for the county is set up, levy not to exceed eight-tenths of one cent on each one hundred dollars upon the taxable value of all the taxable property of the county for the establishment of a drainage fund. No other general levy of any kind shall be made either for operation under the County Drainage Act, for maintenance, for construction, or for any other reason connected with or incidental to the drainage by the county board. Except as provided for in sections 31-920 and 31-922, the money raised from this levy shall be used for the expenses of administering the act, including supervisory and technical expenses, and shall not be used to pay costs and expenses which can be allocated to specific drainage projects.