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, including through the use of geothermal water conveyance systems for the conservation of natural resources. (c) The purposes stated in Subsection (b) of this section may be accomplished by any practical means.