La. Stat. tit. 38 § 1754
The police jury shall create a gravity drainage district when petitioned by a majority in number of acres or a majority of the resident land owners in the area thus to be formed into a gravity drainage district where the area contains forty or less land owners and where the area contains more than forty land owners, then the gravity drainage district shall be created upon petition of twenty-five of the land owners of the district. This resolution creating the gravity drainage districts or the sub-drainage districts shall fix the boundaries thereof, and shall give to the district or sub-district a numerical designation, as follows:
Gravity Drainage District No. __ of the Parish of ______ or Gravity Sub-Drainage District No. __ of Gravity Drainage District No. __ of the Parish of ______.
La. R.S. § 38:1754