Section 11. The clerk of the district shall certify to the assessors of the town or towns in which the land of the district lies all sums of money voted to be raised and all sums payable annually on account of the principal and interest due on bonds or notes issued under the provisions of section nine or ten, together with the amount to be paid by each proprietor according to the determination made under section seven, and said clerk shall also file an attested copy of such certification with the board. The amounts so certified shall be assessed upon the lands of the several proprietors within the area, and be committed to the collector of taxes of the town wherein the land assessed is situated, who shall have and exercise the same powers and duties in relation to the collection of such assessments as he has and exercises relative to the collection of town taxes. The collector shall remit weekly to the district treasurer all sums collected by him on account of such assessments. An assessment made hereunder shall be a lien upon the land assessed therefor, and such lien shall take effect upon the recording of the description, plan and estimate under section seven, and shall continue for a period of two years from July first of the year of assessment.