1. The board shall make an estimate of an amount sufficient to pay the expense of the maintenance and operation of the works erected hereunder, including interest on temporary certificates of indebtedness issued prior to the effective date of the Local Finance Law. If lands in the forest preserve have been used, such estimate shall include in addition a reasonable return to the state upon the value of the rights and property of the state used and the services of the state rendered. A reasonable return to the state upon the value of the rights and property of the state used shall mean six per cent upon the value of the lands flowed, exclusive of merchantable timber and salable wood removed therefrom for which the state shall have been paid as provided by subdivision 8 of section 15-2119 hereof. The value of the services of the state rendered shall be construed to mean the actual cost thereof.

2. Any amount so estimated shall be the estimated amount required for such purposes each year, and when fixed and determined as herein provided shall be the amount thereof for a period of three years. The amount shall be readjustable at the end of any three-year term. The amount less any part thereof to be paid by the state shall be the amount to be annually collected for such purposes, and shall be apportioned upon the public corporations and real estate benefited according to the benefits derived therefrom respectively, and shall be levied, assessed and collected in the same manner as the cost and expenses of the reservoir are herein provided to be levied, assessed and collected.

3. Such estimates and determinations as from time to time fixed and determined by the board may upon application of any party affected thereby be reviewed in the manner provided by article seventy-eight of the Civil Practice Law and Rules by the Supreme Court of the judicial district in which the reservoir is located. Upon the hearing on such application for review, the court shall take the testimony and other proofs of the parties and may make an order affirming, vacating or modifying any such estimate and determination.