Section 7. As soon as the district shall have been organized under the provisions of section six the commissioners shall, under the direction of the board, cause the necessary surveys and investigations to be made and shall prepare a plan showing in detail the boundaries of the district and the improvements to be effected. On the basis of such surveys and investigations the commissioners shall prepare an estimate of the total expense of the proposed improvements and shall determine the percentage of such expense to be paid by each proprietor, based on the estimated special benefit to his land in excess of the damage thereto by the use thereof for the proposed improvements. If such damage to the land of any proprietor exceeds the special benefit thereto they shall award him damages for such excess. They shall report their plan, estimate and determination to the board, which shall approve, disapprove or modify such plan and estimate. The commissioners shall also notify each proprietor of such determination by delivering a copy thereof at his residence or by sending the same by registered mail to his last known address and shall certify to the board the date on which such notice is given. If any proprietor is aggrieved by the determination of the commissioners he may, within fifteen days after notice thereof, file with the board his objections thereto and if no such objections are filed by any proprietor within the fifteen days above specified then the determination of the commissioners shall be final. The board shall, within thirty days after receiving notice of objections by any proprietor against the determination, notify all the proprietors that such objections have been received and shall hold a hearing thereon, but such hearing shall not be held within seven days after notice is given to all the proprietors that objections have been filed. If objections are made by more than one proprietor all such objections shall be considered in one hearing. After such hearing the board may confirm or modify the determination and shall notify the proprietors of its decision. If any proprietor is dissatisfied with the action of the board he may petition the superior court in the county in which the greater part of the land included within the district is situated, making all the proprietors who have not joined in his petition parties respondent and praying for a revision of such decision, provided that such petition shall be entered not later than thirty days after notice of the decision. The court sitting without jury shall hear the petition and shall confirm or alter the percentages previously determined to be payable by any or all said proprietors, as justice may require. Such petition shall not operate to suspend or delay other proceedings by the board or commissioners on the land to be improved. The expenses incurred under this section shall constitute a part of the total expense of the improvements and shall be paid by the district in the same manner as the remainder of such expense.

As soon as the percentages payable as aforesaid by said proprietors in the case of original and of further improvements have been finally determined in accordance with this section the board shall on behalf of the reclamation district cause to be recorded in the registry of deeds of every county or district in which the benefited area is situated a description sufficiently accurate for identification of such area, a copy of a plan to which reference shall be made and also an estimate of the total amount to be assessed on each parcel of land within such area, all as set forth in section two of chapter eighty. No original or further improvements shall be approved by the board until after such recording.