Water Code §51.121

(a) A water control and improvement district organized under the provisions of Article III, Section 52 , of the Texas Constitution, may provide for: (1) the improvement of rivers, creeks, and streams to prevent overflows, to permit navigation or irrigation, or to aid in these purposes; or (2) the construction and maintenance of pools, lakes, reservoirs, dams, canals, and waterways for irrigation, drainage, or navigation, or to aid these purposes. (b) A water control and improvement district organized under the provisions of Article XVI, Section 59 , of the Texas Constitution, may provide for: (1) the control, storage, preservation, and distribution of its water and floodwater and the water of its rivers and streams for irrigation, power, and all other useful purposes; (2) the reclamation and irrigation of its arid, semiarid, and other land which needs irrigation; (3) the reclamation, drainage, conservation, and development of its forests, water, and hydroelectric power; (4) the navigation of its coastal and inland water; (5) the control, abatement, and change of any shortage or harmful excess of water; (6) the protection, preservation, and restoration of the purity and sanitary condition of water within the state; and (7) the preservation and conservation of all natural resources of the state. (c) The purposes stated in Subsection (b) of this section may be accomplished by any practical means.