A. When flood waters of a river, creek, channel or canyon injure or threaten to injure a public road or highway, or public property, or become a menace to human life and habitation, the board may build dikes, levees or other structures or aid in the construction of such works to control the flood waters or lessen their destructive effects.

B. For such purpose the board may appropriate and use in any one year from the general fund an amount not to exceed fifteen cents on each one hundred dollars of taxable property in the county. If there is not sufficient money in the general fund to meet the appropriation, the board may issue certificates of indebtedness against the fund. When the board uses money from the general fund for such purpose, it may, at the next general levy of taxes, levy upon real and personal property within the county subject to taxation, a tax sufficient to cover the amount so used not exceeding fifteen cents on each one hundred dollars of assessable property, which shall be levied and collected at the time and in the manner as other taxes. If at the time of such levy there has been no expenditure of money for such purpose, but the board has made and perfected plans for the construction of dikes, levees or other works for such purpose, it may levy a tax for completion thereof not exceeding the amount authorized.