The provisions of this Part shall apply only to drainage districts organized under La. Const. Art. XV of Louisiana of 1921, or reorganized under the provisions of this Part, for the purpose of draining and reclaiming the undrained marsh, swamp and overflowed lands in the State of Louisiana that must be leveed and pumped in order to be drained and reclaimed, and nothing in this Part shall apply in any way to gravity drainage districts as provided for in La. Const. Art. XIV.  This Part shall be considered the general law on the subject of drainage or reclamation districts under which all drainage or reclamation districts created in the future must organize.