1. (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 and 11.153, 11.155), 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.
2. (b) A new water right may be conditioned as appropriate to protect 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.
3. (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.
4. (d) Projects that are not required to be based upon the continuous availability of historic, normal stream flow include, but are not limited to: the artificial recharge of the Edwards Aquifer under TWC, §11.023(c); conjunctive ground and surface water management projects such as aquifer storage and recovery 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; 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.
5. (e) 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 30 TAC §290.41(b) 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.
6. (f) 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.
7. (g) 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.

Source Note: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.