(a) The district includes the territory provided by Section 2 of the Act creating this chapter, as that territory may have been modified under:
(1) Subchapter J, Chapter 49, Water Code; or
(2) other law.
(b) The boundaries and field notes contained in Section 2 of the Act creating this chapter form a closure. A mistake made in the field notes or in copying the field notes in the legislative process does not affect:
(1) the organization, existence, or validity of the district;
(2) the right of the district to impose taxes; or
(3) the legality or operation of the board.