In a county that has river frontage on both the Guadalupe and Comal rivers, a district may be created for all or part of the unincorporated area in the county to:
(1) improve, equip, maintain, finance, and operate any public park located in the district and owned or leased by the county;
(2) conserve the natural resources in the district; and
(3) improve the public health, safety, and welfare in the district.