N.C. Gen. Stat. § 156-98
All bonds and notes authorized and issued shall be signed by the chairman and secretary of the board of drainage commissioners and the corporate seal of the district affixed thereto, and the interest coupons shall be authenticated by the facsimile signature of the secretary, and both the principal and interest coupons shall be payable at some bank or trust company to be designated by the board of drainage commissioners and incorporated in the body of the bond. The form of the bond shall be authorized by the board of drainage commissioners or by the board and the purchaser of the bonds jointly, at the option of the board.
All bonds of reclamation districts shall have that fact noted upon the face of the bond, either by stamping or printing the same thereon. All bonds of improvement districts shall also have that fact noted upon their face.
For the purpose of meeting any possible deficit in the collection of annual drainage assessments or any deficit arising out of unforeseen contingencies there shall be levied, assessed and collected during each year when either the interest or principal or both interest and principal on the outstanding bonds shall be due, an assessment as will yield ten percent (10%) more than the total of interest and principal due in such years; that is to say, for every one hundred dollars ($100.00) of principal and interest, or either, due in any one year, there shall be levied, assessed and collected a sufficient drainage assessment to yield one hundred and ten dollars ($110.00) for such year. When this excess of drainage tax so levied, assessed and collected shall accumulate so that the aggregate surplus in the hands of the treasurer of the district shall amount to more than fifteen percent (15%) of the total principal of the bonds of the district outstanding and unpaid, then such surplus above fifteen percent (15%) thereof may be available for expenditure by the board of drainage commissioners in the maintenance and upkeep of the drainage work in such district in the manner provided by law: After all the drainage assessments have been collected except the last assessment, if the surplus which has accumulated amounts to more than five percent (5%) of the total issue of bonds of the district, then and in such event the board of drainage commissioners may in their discretion apply such excess above five percent (5%) toward the reduction of the total amount embraced in the last assessment, reducing the same pro rata as to each tract of land embraced in the district, and having regard to the classification, to the end that such reduction shall be fairly and justly made. As to such surplus as shall accumulate in the hands of the treasurer of the district over and above all obligations of the district which may be due, the treasurer is hereby directed to deposit same in some solvent bank or banks at the highest rate of interest obtainable therefor, and the said treasurer shall be authorized, if he deems it necessary, to demand satisfactory security for such deposits; but the said treasurer shall reserve the right to demand a repayment at any time upon giving not exceeding 30 days' notice thereof. Whereas the proceeds of the first drainage assessment may not be collected and in the hands of the treasurer of the district prior to the maturity of the first and second semiannual installments of interest upon the issue of bonds, the treasurer of the district is hereby directed to pay the interest coupons first maturing and also the interest coupons next maturing, if necessary, out of funds in his hands for the purpose of maintaining the improvement for the period of three years after the completion of the work or construction. As a surplus fund with the treasurer arising out of the annual additional assessment of ten per centum (10%) shall accumulate in any one year in excess of fifteen per centum (15%) of the total principal of the bonds of the district outstanding and unpaid, as herein provided, the treasurer shall transfer in each of such years such surplus fund to the fund for maintaining the improvement after completion, as a reimbursement of the fund formerly withdrawn therefrom for the payment of the first and second installments of interest coupons until such reimbursement shall be fully made. The treasurer shall thereafter keep separate accounts of the proceeds of such additional ten percent (10%) assessment remaining each year after the payment of all maturing obligations, and also a separate account of the funds provided for maintaining the improvement for the period of three years after completion of improvement and all payments therefrom and reimbursements thereto.
N.C. Gen. Stat. § 156-98