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CDOW Rebuttal Statement - Regulation 37 <br />December 2010 Reg. 37 Rule-Making Hearing <br />elevation of 5000 feet to the Government Highline Canal. <br />The WQCD's proposed Segment 13e would be classified with Warm 2 Aquatic Life, <br />Recreation P, and Agriculture uses. The segment also would be given an Undesignated <br />(Reviewable) antidegradation designation. The segment would retain physical and <br />biological standards for protection of aquatic life and recreation, while standards for <br />inorganics and metals generally would be ambient quality-based. <br />An important difference between the alternative offered by the WQCD an d the proposal <br />advanced by CAM is the geographic scope of proposed Segment 13e; the WQCD's <br />proposal has a more refined scope than CAM's original proposal, which was focused on <br />the resegmentation of a relatively large geographic area. Streams throughout much of the <br />area proposed by CAM for inclusion in Segment 13e were evaluated only at single <br />reconnaissance sites where no biological surveys were conducted (CAM Exhibit 4; , <br />Figure 1, page 7). Additionally, the CDOW has noted its concern that several streams <br />were not surveyed for biological data despite observations of water (CDOW RPHS, page <br />3). The CDOW also discussed concerns about inclusion of West Salt Creek and Big Salt <br />Wash in CAM's original proposal given similarities between these streams and East Salt <br />Creek, which was excluded by CAM from its originally proposed Segment 13e (CDOW <br />RPHS, page 3). A more limited geographic scope for proposed Segment 13e would <br />address some of the CDOW's concerns. <br />The scope of the proposal is particularly important because biological communities in <br />and intermittent and ephemeral streams are likely to vary substantially both temporally <br />and spatially. This is exemplified by CDOW surveys of East Salt Creek on June 22, <br />2010. During these surveys, dry conditions were observed at the lowest survey site, <br />located at the juncture of East Salt Creek and Mitchell Road (39.3419122,-108.8443675), <br />but water and the presence of numerous juvenile fish and tadpoles were observed just <br />upstream of the Mesa County line in Garfield County (39.3895872,-108.8195283, <br />Elevation = 5,044 ft). Had CDOW personnel only surveyed the downstream site, an <br />erroneous conclusion could easily have been drawn regarding the capacity of the stream <br />to support aquatic life, including reproducing fish. <br />Survey methods commonly employed for perennial streams also may prove ineffectual in <br />and drainages. During the CDOW's 2010 surveys of East Salt Creek, high conductivity <br />generally rendered electrofishing ineffective. However, the use of seine nets and dip nets <br />facilitated the capture of hundreds of juvenile and larval fish during follow-up surveys on <br />June 30 -July 1, 2010. On November 8, 2010, the CDOW received confirmation from <br />the Colorado State University Larval Fish Laboratory that the majority of these juvenile <br />and larval fish were native flannelmouth sucker (Table 1). Minnow traps also were set in <br />East Salt Creek on June 30, 2010 at elevations of 5,034 ft, 5,045 ft, and 5,679 ft <br />(39.3888039,-108.8190767; 39.3906094,-108.8187997; 39.4833353,-108.7549714). <br />Upon retrieval the following day (July 1, 2010), the downstream and upstream traps <br />contained no fish, but the trap at 5,045 ft contained 15 adult fathead minnows, including <br />males displaying spawning colors. Here again, reliance on a single sampling point or a <br />single sampling technique could have resulted in an erroneous conclusion regarding the <br />December 1, 2010