30 Tex. Admin. Code § 297.24
Except as provided by the Texas Water Code, §11.142, a permit is required for an impounding structure that is not directly on a watercourse, if the reservoir is to impound state water and the commission deems that the impoundment is necessary to grant authorization to divert and use state water. The permit will authorize the appropriation of state water to fill the reservoir, divert and use the water, or use the water in place. This definition does not include in-system balancing reservoirs operating under authorized permits.
Source Note:The provisions of this §297.24 adopted to be effective May 29, 1986, 11 TexReg 2330.