(1) The tax shall be apportioned to and levied on each tract of land in said district in proportion to the benefits assessed and not in excess thereof, and, in case bonds are issued, the amount of the interest, as estimated by said board of directors, which will accrue on such bonds shall be included and added to the tax, but the interest to accrue on such bonds shall not be construed as a part of the cost of construction in determining whether or not the expenses and costs of making said improvements are or are not equal to or in excess of the benefits assessed.

(2) In case bonds are issued, said tax shall be divided into such number of annual installments as will meet the requirements of and provide for the punctual payment of the interest upon and the principal of the bonds as the same accrue. In case the proceeds of the original tax levy are not sufficient to pay the principal of and the interest upon all of the bonds which may at any time be issued, then the board of directors shall make such additional levies upon the benefits assessed, but not in excess thereof, as are necessary to pay such principal and interest. If it is found at any time that the amount of total taxes levied is insufficient to pay the cost of the works set out in the plan for a drainage system or to pay the cost of the additional work, the board of directors may make an additional levy to provide funds to complete the work; but the total of all such levies shall not exceed the total amount of benefits assessed.

(3) The secretary of the district, as soon as said total tax is levied, at the expense of the district, shall prepare a list of all taxes levied in the form of a well-bound book, which book shall be endorsed and named: "..........… Drainage District Assessment Book", which endorsement shall also be printed or written at the top of each page in said book, and it shall be signed and certified by the president and secretary of the district, under the seal thereof, and the same shall thereafter become a permanent record in the office of said secretary, and a certified copy thereof shall be transmitted to the proper county assessor.