1. (a) Minimum acceptable spillway design flood. The hydrologic criteria contained in Table 3 are the minimum acceptable spillway design flood (SDF) for proposed dams as defined in §299.1 of this title (relating to Definitions), including those to be constructed in accordance with the Texas Water Code, §11.142.
2. (b) Exemptions to minimum hydrologic criteria. Proposed low hazard dams exempt under the Texas Water Code, §11.142, are exempt from the minimum criteria. Any other proposed structure may be exempt from the minimum criteria if properly prepared dam breach analyses show that existing downstream improvements or known or planned future improvements will not be adversely affected. A properly prepared breach analysis should include at least three events, the normal storage capacity nonflood event, the barely overtopping event, and the PMF event. Data on additional flood magnitudes may be provided as necessary to document other conditions or conclusions. Downstream flooding differentials of one-foot or less between breach and nonbreach simulations are not considered to be adverse.

Source Note:The provisions of this §299.14 adopted to be effective May 13, 1986, 11 TexReg 1978.