Refund of certain special assessments.

If a dependent special district has levied assessments for an improvement or specialized function for which it was created; no bonds have been issued against which the special assessments are pledged; and the county or municipality which created the special district determines that the demand for the improvement or function no longer exists or the majority of the land against which the special assessments were authorized has been purchased by a tax-exempt governmental agency to be preserved for environmental purposes and which cannot receive the benefit for which the assessments were levied, unspent and unobligated moneys collected as assessments, along with any interest collected thereon, shall be refunded to the original payors of the assessments when the costs of distributing the refund do not exceed the amount available for refund. This section shall operate retroactively to January 1, 1987.