Mo. Rev. Stat. § 233.135

Such board may issue check warrants on the treasurer of the board in payment of the expenses and obligations which the board is authorized to incur in behalf of such special road districts and such check warrants may be issued in anticipation of the income and revenue provided for the year for which the debt or obligation for which the check warrant is issued was incurred; but such districts or such board on behalf thereof shall not become indebted in any manner or for any purpose to an amount exceeding in any one year the income and revenue provided for such year; provided, however, that this shall not prevent the incurring of indebtedness under bond issue as is or may be provided by law.