85-8-404. Appeals and assessments. A party interested in the hearing under 85-8-402 who is aggrieved by the order of the court may appeal from the order to the supreme court of Montana within 30 days after the entry of the order. If an appeal is not taken within the time limit, the order of the court made upon the hearing is final and conclusive. If alterations or additions are authorized by the order, the alterations or additions must be made by the commissioners of the district and the cost apportioned in accordance with the last assessment roll of the drain district or in accordance with the last assessments of the drainage district confirmed by the court.