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COMMENTS OF U.S. ENVIRONMENTAL PROTECTION AGENCY <br />restriction on the incremental change to a water's temperature <br />regime from natural. The absolute temperature maximum specified <br />for coldwater aquatic ecosystems, for warmwater aquatic <br />ecosystems and for segments of the Missouri River differ due to <br />differences in the expected resident aquatic species of those <br />waters. This approach is consistent with EPA's guidance criteria <br />which establish temperature maximums based on sensitive resident <br />aquatic species. These temperature maximums are developed with <br />the intent to protect the designated aquatic life uses in those <br />waters (e.g., Aquatic Life - Coldwater (Class A and B) and <br />Warmwater (Class A and B)) and are not dependent upon the <br />presence of a discharge. The adopted criteria represent ambient <br />conditions necessary to protect aquatic life. The incremental <br />change component of the state's temperature criteria addresses <br />the need to restrict large shifts in ambient temperature beyond <br />"natural" where "natural" may be lower than the absolute <br />temperature maximum. <br />Finally, the temperature criteria contained in N.A.C. Title <br />117, Chapter 2, apply not to discharges but to surface waters. <br />Chapter 2, Section 001, states that "[t)hess standards shall <br />apply at all times to all surface waters of the State..." <br />Section 006 of Chapter 2 further states that <br />These standards may be applied through Title 119 - Rules and <br />Regulations Pertaining to the Issuance of Permits Under the <br />National Pollutant Discharge Elimination System and Title <br />120 - Procedures Pursuant to Section 401 of the Federal <br />Clean Water Act, 33 U.S.C. Section 1251 et aea., for <br />Certification by the Department of Activities Requiring a <br />Federal License or Permit which May Result in a Discharge. <br />Clearly, the application of standards is not limited to these <br />implementation mechanisms, but the state water quality standards <br />explicitly place the water quality standards, including <br />designated uses and criteria to protect them, within the purview <br />of the states' certification responsibilities. <br />In EPA's DEIS comment letter dated June 15, 1992, our <br />scoping comment letter for the RDEIS dated February 11, 1993, and <br />verbally during technical meetings that were held regarding <br />development of the RDEIS, EPA asked FERC to explain how it <br />intends to comply with the state's temperature maximum. The <br />RDEIS discusses the issue of the relationship between temperature <br />and flow and how increased flow can moderate high temperatures. <br />As the RDEIS recognizes, "water quality in the Big Bend Reach of <br />the Platte River is limited by low summer flows that increase the <br />frequency of water temperatures exceeding the state standard (32° <br />C) ... such that aquatic life would be threatened." (RDEIS, page <br />4 -19). However, FERC does not discuss how the preferred <br />alternative or any other alternative presented in the RDEIS will <br />specifically meet this state water quality standard. <br />RESPONSES TO U.S. ENVIRONMENTAL PROTECTION AGENCY <br />