1998-02-25_HYDROLOGY - M1977493 - Laserfiche WebLink

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Letter to Bryce Romig 3 April 6. 1998 authority. The Division disagrees with this statement. However,the Division agrees with CMC's position that since the pH of the East Fork of the Eagle River and the reservoir are statistically the same there would not be a significant difference between dissolved and potentially dissolved metals concentrations. Please provide pH data for the East Fork of the Eagle River to validate the similarity of the pH of the reservoir and stream. Assuming validation, the Division agrees that future analysis for dissolved metals can be completed by using the dissolved metals analytical method, rather than the potentially dissolved analytical method. C. In the CMC letter dated March 10, 1998, it is stated that"the antidegradation regulation does not apply in this case." The Division agrees with this statement, and is not applying the antidegradation regulation as a component of the process of determination if the post-mining land use has been achieved. Rather,the Division must make a finding that the proposed post-mining land use of developed water resources has been achieved through the removal of tailings from the tailings pond. An analogy is the case where a gravel operator proposes to reclaim a gravel pit, where tributary ground water is exposed, to a water storage reservoir. In such cases the Division requires construction of a lining to prevent the inflow of ground water, and a demonstration that the structure meets the tributary ground water leakage criteria specified by the State Engineer. Finally, an operator must provide bond sufficient to assure that the reservoir will be filled with water at least one time. The rationale being that a lined pit does not constitute a water storage reservoir unless it is actually put to that use. In this manner, the operator has demonstrated that the post-mining land use has been achieved, and the Division can release the site. A finding that the State Engineer's leakage criteria has been met is critical to this process. Similarly, by demonstrating that the reclaimed tailings pond will not aversely affect the intended use of water stored therein, CMC will have demonstrated that reclamation of Eagle Park Reservoir is a success. A finding related to antidegradation is integral to this process. In the letter dated March 10, 1998, CMC has provided an adequate demonstration, based on available data, that significant degradation of the stream would not occur as the result of reservoir releases. d. The Division concurs with CMC's plan to continue sampling through the fourth quarter of 1998 at the three established sampling points on the north, east, and south shores of the reservoir, and at a surface and 35 foot depth sample point in the center of the reservoir. Please provide a description of the sample collection and preservations methodologies to be employed for the depth sample. The Division suggests that the following sampling plan be implemented during reservoir releases scheduled for the fall of 1998 and 1999. A sample should be collected on the first day of reservoir releases during each seasonal release period, a second sample collected at the approximate midpoint of the release period, and a third sample collected near the termination of the release period. These samples are to be collected at the outfall of the outlet works in order to provide water quality data for the water that is actually being delivered into the stream. CMC provided three reasons in support of a request to conduct sampling during reservoir releases at the established north shore sampling location rather than at the delivery point. The Division's rationale for specification of sampling at the delivery point, as opposed to CMC's suggested alternate point, are provided in the following list: ► CMC suggests that sampling at the north shore location during reservoir releases would be superior to sampling at the outfall because the north shore sampling point has established