Section 297.42 - Water Availability(a) Except as provided by Texas Water Code (TWC), § 11.1381, and § 297.19 of this title (relating to Term Permit under Texas Water Code, § 11.1381) , an application for a new or increased appropriation will be denied unless there is a sufficient amount of unappropriated water available for a sufficient amount of the time to make the proposed project viable and ensure the beneficial use of water without waste.(b) A new water right may be conditioned as appropriate to protect any applicable environmental flow standards as described in Chapter 298 of this title (relating to Environmental Flow Standards for Surface Water), and, if applicable, instream uses, water quality, aquatic and wildlife habitat, and freshwater inflows to bays and estuaries as provided by TWC, §§11.147, 11.150, 11.152, and 16.059.(c) For the approval of an application for a direct diversion from a stream without sufficient on or off channel water storage facilities for irrigation, approximately 75% of the water requested must be available approximately 75% of the time when distributed on a monthly basis and based upon the available historic stream flow record. Lower availability percentages may be acceptable if the applicant can demonstrate that a long-term, reliable, alternative source or sources of water of sufficient quantity and quality are economically available to the applicant to make the proposed project viable and ensure the beneficial use of state water without waste.(d) Projects that are not required to be based upon the continuous availability of historic, normal stream flow include, but are not limited to: conjunctive ground and surface water management projects; diversions or impoundments at times of above-normal stream flow (e.g., "scalping" operations) for seasonal or supplemental use; a system operation in conjunction with other water rights; non-consumptive instream uses except for instream flows dedicated to environmental needs or inflows to the state's bay and estuary systems, pursuant to TWC, §11.0237(a); or other similar type projects. The required availability of unappropriated water for these special type projects shall be determined on a case-by-case basis based upon whether the proposed project can be viable for the intended purposes and the water will be beneficially used without waste.(e) New appropriations of water for recharge into an aquifer underlying this state, including aquifer recharge projects as defined by TWC, §27.201 or for storage in an aquifer storage and recovery project before the water is recovered for a beneficial use may be for water that is not continuously available. Water availability for the full amount of water requested for these types of projects must, at a minimum, be available at least one year in the period of record based on the commission's water availability model for the applicable river basin, and the proposed project must be viable for the intended purposes and the water must be beneficially used without waste.(f) New appropriations of water based on an increase in the amount of water diverted or the rate of diversion resulting from an evaporation credit under TWC, §11.158(c) may be for water that is not continuously available, as defined in subsection (e) of this section. Water availability for projects under this subsection that request an increase in the amount of water diverted or the rate of diversion from an on-channel reservoir that has not been constructed shall be based on the evaporation calculations that were used in developing the terms of the water right for which the amendment is sought and cannot exceed the maximum annual modeled evaporation as determined in the commission's water availability model for the applicable river basin.(g) The volume of water available for conversion of a water right that authorizes storage in a reservoir that has lost storage capacity because of sedimentation to storage as part of an aquifer storage and recovery project, as described in TWC, §11.158(d), does not have to be continuously available, as defined in subsection (e) of this section. The volume of water that can be converted to storage in an aquifer storage and recovery project under this subsection is limited to the lesser of: (1) the storage volume that is demonstrated to have been lost to sedimentation, as determined by a survey performed by the Texas Water Development Board; or(2) the volume of storage in the aquifer storage and recovery project that would restore the amount of previously authorized storage capacity lost to sedimentation.(h) For an application for an on-channel storage facility to be authorized for domestic or municipal water use, the proposed diversion right of the reservoir must be equal to its firm yield. The purpose of this limitation is to ensure a secure and dependable source of water supply for uses necessary to protect the public health, safety, and welfare (see also § 290.41(b) of this title (relating to Water Sources) requiring public water systems to have a "safe" yield capable of supplying the maximum daily demands during extended periods of peak usage and "critical hydrologic conditions"). Such reservoir may be authorized in excess of its firm yield when the implementation of a drought management plan or alternative sources of water supply such as groundwater, other reservoir systems, or other means are available to satisfy water needs during drought periods when the reservoir's normal supply capabilities would be exceeded.(i) Except for an application for an emergency, temporary, seasonal, or term permit, or as provided by this section, the commission may require an applicant to provide storage sufficient to yield the requested annual diversion.(j) In order to make the optimum beneficial use of available water, a water right may be granted based upon the availability of return flows or discharges. However, a water right granted upon return flows or discharges that may cease in the future because of new or increased direct reuse (i.e., the lawful reuse of water before it is returned or discharged into the stream) or that may cease for other lawful reasons will be granted with the express provision that the water available for the water right is dependent upon potentially interruptible return flows or discharges.30 Tex. Admin. Code § 297.42
The provisions of this §297.42 adopted to be effective February 24, 1999, 24 TexReg 1162; amended to be effective August 15, 2002, 27 TexReg 7152; Amended by Texas Register, Volume 45, Number 21, May 22, 2020, TexReg 3457, eff. 5/28/2020