La. Stat. tit. 38 § 476
For the purpose of providing for the payment of the principal of the bonds issued under this Subpart as they mature, the levee board or levee and drainage board shall levy in an amount sufficient to pay the bonds maturing in each year the taxes and local contributions which they are authorized and empowered to levy, as well as any taxes and local contributions which they may hereafter be authorized to levy. From the first moneys realized from the taxes and local contributions, the state treasurer after providing for the payment of the principal and interest of the bonds shall set apart an amount sufficient to pay the principal of the bonds maturing that year, and the money thus set apart shall not be diverted to any other purpose.
La. R.S. § 38:476