Okla. Stat. tit. 82, § 82-634: Levy of assessments

After the list of real property, with the appraised benefits as

approved by the court, or that part thereof from which no appeal is

pending has been filed with the secretary of the district, then from

time to time, as the affairs of the district demand it, the board of

directors shall levy on all real or other property upon which

benefits have been appraised, an assessment of such portion of said

benefits as may be found necessary by said board to pay the cost of

the execution of the official plan including superintendence of

construction and administration, plus ten percent (10%) of said

total, to be added for contingencies, but not to exceed, in the

total of principal, the appraised benefits so adjudicated. The said

assessment shall be apportioned to and levied on each tract of land

or other property in said district in proportion to the benefits

appraised, and not in excess thereof and in case bonds are issued as

provided herein and hereafter, then the amount of interest, which

will accrue on such bonds, as estimated by said board of directors,

shall be included in and added to the said assessment, but the

interest to accrue on account of the issuing of said 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 appraised. As

soon as said assessment is levied, the board shall report it to the

court for confirmation. Upon the entry of the order of the court

confirming the assessment the clerk of the court shall transmit a

certified copy of said order to the governing or taxing body of each

political subdivision assessed and said governing or taxing body

shall receive and file the same. After the court has confirmed the

assessment, the secretary of the board of directors, at the expense

of the district, shall prepare in duplicate an assessment record of

the district.