Neb. Rev. Stat. §§ 16-652
The cost of grading the streets and alleys within a grading district in a city of the first class shall be assessed upon the lots and lands specially benefited thereby in such district in proportion to such benefits, to be determined by the mayor and city council under section 16-615, as a special assessment. The special assessment for grading purposes shall be levied at one time and shall become delinquent as follows: One-fifth of the total amount shall become delinquent in fifty days after such levy; one-fifth in one year; one-fifth in two years; one-fifth in three years; and one-fifth in four years. Each of the installments, except the first, shall draw interest at a rate not to exceed the rate of interest specified in section 45-104.01, as such rate may from time to time be adjusted by the Legislature, from the time of the levy until the installment becomes delinquent. If the installment becomes delinquent, interest at the rate specified in section 45-104.01, as such rate may from time to time be adjusted by the Legislature, shall be paid thereon, as in the case of other special assessments. The cost of grading the intersections of streets and spaces opposite alleys in any such district shall be paid by the city out of the general fund of such city.
Neb. Rev. Stat. §§ 16-652