La. Stat. tit. 38 § 1761
In the event of the creation of a gravity drainage district within two or more parishes, the drainage commissioners shall be appointed or selected as aforesaid, three by the police jury of the parish which has the greatest area in the district and two by the police jury of the other parish. When all or portions of three parishes are included, two commissioners shall be appointed by the governing authority of the parish having the greatest area in the district, two shall be appointed by the governing authority of the parish having the second largest area in the district, and one shall be appointed by the governing authority of the other parish. When all or portions of four parishes are included, two commissioners shall be appointed by the governing authority of the parish which has the greatest area in the district and one commissioner shall be appointed by the governing authorities of each of the other parishes. When all or portions of five parishes are included, the governing authorities of each of the parishes shall appoint one commissioner. When all or portions of more than five parishes are included, the governing authorities of the five parishes having the greatest acreage in the district each shall appoint one of the five commissioners. When all or portions of more than one parish are included within the district, the commissioners shall determine the terms by drawing lots for the long and short terms. Any commissioner so appointed may be removed for cause by the police jury appointing him. Failure or refusal by a commissioner to perform any or all of the duties prescribed by this Part shall be good cause for removal.
La. R.S. § 38:1761