Neb. Rev. Stat. §§ 31-334
Whenever it shall appear to the satisfaction of the board of supervisors that the levy theretofore made will be insufficient to pay the cost of the improvement or to pay the interest and principal of the bonds which the district desires to issue to pay the cost of such improvement, and that therefor a supplemental assessment is necessary to be made as provided in section 31-332, the board shall, by a resolution duly passed and entered in the record of its proceedings, declare the amount of such deficit and the purpose to which such supplemental assessment should be applied, and shall thereupon cause a supplemental assessment roll to be made, which shall apportion the amount necessary to be raised and declared as aforesaid upon the lands in the proportion of the former assessment, and shall set opposite each parcel of land (described by its legal description) the amount of such supplemental assessment expressed in dollars and cents. Upon such roll the real estate and the amounts of the several assessments may be described by current and usual abbreviations, if the board so desires. Thereupon the board shall proceed to enter judgment by confirmation upon such supplemental assessment roll, and such supplemental assessments shall be levied and certified in all respects as provided for herein. From time to time, and as often as occasion may arise, supplemental assessments may be levied as in this section provided. In the event that any supplemental assessment is levied before any bonds are issued by the district, it shall be divided into installments, payable when the installments of the first original assessment are payable, and shall be collected therewith, and together they shall constitute one fund against which drainage bonds may be issued as herein provided.
Neb. Rev. Stat. §§ 31-334