2011-02-15_REVISION - C1980004 (2)

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CDOW Rebuttal Statement — Regulation 37 December 2010 Reg. 37 Rule- Making Hearing CAM's proposed Segment 13e would retain the Use - Protected antidegradation designation, and it would be classified as Warm 2 Aquatic Life, Recreation N, and Agriculture. Water - quality standards would be set to protect livestock watering. Only standards for temperature would be set for protection of aquatic life. In its RPHS, the CDOW outlined several areas of concern regarding CAM's proposal, and these points are summarized below: • The CDOW disagreed with CAM's assertion that the proposed resegmentation separates "the dry gulches that clearly do not support aquatic life from the intermittent /perennial aquatic systems in Segment 13a that potentially contain aquatic life and support other uses" (CAM PHS, page 8; CDOW RPHS, page 3). Aquatic life was documented during all biological surveys, and, while other streams proposed for inclusion in Segment 13e support periodic flow4nd intermittent pools (e.g., Camp Gulch, Unnamed Tributary 6), they were not surveyed for aquatic life when water was observed. The EPA and the WQCD expressed similar concerns regarding CAM's conclusion that the streams proposed for inclusion in proposed Segment 13e do not support aquatic life (EPA RPHS, page 5; WQCD RPHS, page 3). The CDOW supported retention of standards for pH (6.5 -9.0) and dissolved oxygen (5A mg/L) (CDOW RPHS, page 3). The EPA and the WQCD also recommended retention of these standards (EPA RPHS, page 4; WQCD RPHS, page 5), which are appropriate for protection of warm -water aquatic life and consistent with standards for other segments classified with the same uses and antidegradation designation as proposed by CAM for Segment 13e (CDOW RPHS, page 3) • CAM has proposed standards for metals that are, in many cases, significantly higher than those of existing Segment 13a, and the CDOW requested that CAM provide more evidence to support that its proposed standards would be adequate to protect aquatic life in proposed Segment 13e (CDOW RPHS, page 4). The WQCD also noted the substantial relaxation of the existing standards and requested that CAM provide additional evidence to support that its proposal____. would'be protective of "the fnveitebrate community (WQCD RPHS, page 4). • The CDOW provided additional discharge and water - quality data from the U.S. Bureau of Land Management (BLM) (CDOW Exhibit 1) and recommended exclusion of Big Salt Wash and West Salt Creek from CAM's proposed Segment I 3 (CDOW RPHS, page 4). Many of these data also were provided by the WQCD (WQCD Exhibit 1), and the WQCD also noted the likelihood that West Salt Creek and Big Salt Wash are "nearly perennial" (WQCD RPHS, page 3). In addition to commenting on the CAM proposal, the WQCD has developed an alternative proposal for Segment 13e, which would be defined as: Lower Colorado River Se ment 13e (Proposed by the W CD : All East Salt Creek tributaries east of the mainstem that have a confluence with East Salt Creek from an December 1, 2010