The proportionate share of the cost of future work by the drainage district to be borne by the municipal corporation shall constitute the measure of liability of the municipal corporation to the drainage district and may be enforced by mandamus. The proportionate share as fixed by the court may be set aside or modified by a subsequent contract approved by the court or may be set aside or modified by the court upon application by the drainage district or by the municipal corporation when circumstances have so changed as to make the proportionate share inequitable or unjust as to either party. Notice of the hearing on any petition to modify the proportionate share shall be given as the court may direct.
70 ILCS 605/8-22