La. Stat. tit. 38 § 1901
The governing authority of any gravity drainage district or gravity sub-drainage district when authorized so to do by a vote of a majority in number and amount of the property tax payers qualified to vote under the Constitution and laws of this state in the gravity drainage district or gravity sub-drainage district, may levy and collect an acreage tax or forced contribution not to exceed thirty-five cents per acre per year on the land in the gravity drainage district or gravity sub-drainage district for a period not to exceed ten years. The acreage tax or forced contribution shall not be funded into bonds but shall be annually collected and used for the purpose of maintaining, improving, and keeping in repair the system of gravity drainage constructed in the gravity drainage district or gravity sub-drainage district, all within the limits prescribed in the provisions of Section 14 of Article XIV of the Constitution.
La. R.S. § 38:1901