Neb. Rev. Stat. § 17-924: Neb. Rev. Stat. § 17-924

All the special assessments provided for in section 17-921 shall, when levied, constitute a sinking fund for the purpose of paying the cost of the improvements authorized pursuant to section 17-913 with allowable interest thereon, and shall be solely and strictly applied to such purpose to the extent required. Any excess assessments may be transferred to such other fund or funds as the city council or village board of trustees may deem advisable after fully discharging the purposes for which they were levied.