No irrigation district may in any year issue warrants in excess of ninety percent of the levy for the year. However, in case of due and outstanding obligations against the district on account of operation, maintenance, and current expenses contracted before the year in which any levy is made, the district board may make an additional levy, not to exceed one dollar per acre upon all irrigable lands within the district, to create a special fund for the payment of past due obligations.
SDCL 46A-7-45