La. Stat. tit. 38 § 451
The board of commissioners of any levee district or levee and drainage district in Louisiana may issue bonds of the district in addition to any bond which it may by law now issue for the purpose of paying, refunding, or refinancing the principal and interest of any valid outstanding bonds, notes, or certificates of indebtedness heretofore or hereafter issued by the district for lawful purposes. The refunding bonds may be issued on or prior to the maturity of the outstanding bonds, notes, or certificates of indebtedness or on or prior to any date upon which they may be redeemable, or upon the surrender of the bonds, notes, or certificates of indebtedness by the holders thereof prior to maturity. The bonds shall be known as "Levee Refunding Bonds", and shall mature at a date or dates, not exceeding forty years from the date they bear, and in the amounts which shall be prescribed by the boards of commissioners of the districts respectively. The bonds shall bear interest as provided in R.S. 39:1421 et seq. payable semiannually and shall be sold at the time and in the amount which the boards of commissioners of the levee districts and levee and drainage districts shall determine. Refunding bonds shall not be issued in an amount exceeding the par value and accrued interest thereon of the bonds, notes, or certificates so to be paid, refunded, or refinanced. In the event that the bonds bearing interest at the same rate as specified in the bonds, notes, or certificates of indebtedness to be refunded cannot be sold for their par value and accrued interest, then the board of commissioners may provide for the issuance and delivery of the bonds in exchange for and upon surrender and cancellation of a like amount of the outstanding bonds, notes, or certificates of indebtedness and accrued interest to be refunded.
La. R.S. § 38:451