5 Colo. Code Regs. § 1002-36.38
The provisions of C.R.S. 25-8-202(1)(i) and 25-8-401(2) provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.
BASIS AND PURPOSE
Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications scheduled to expire before December 31, 2017, to determine whether the temporary modification should be modified, eliminated or extended. In addition, other standards actions were taken.
Rio Grande segments 4a and 7: Metals, revised standards effective dates and temporary modifications expiration dates.
At the December 2013 Temporary Modification hearing the Commission adopted site specific standards with delayed effective dates and temporary modifications in Rio Grande segments 4a and 7. These standards represent predicted improvements in water quality due to the dilution effect of treated effluent from the Bulldog Mine in Tier 1 and water-quality improvement predicted by a 90% reduction in flow and metal load from the Nelson Tunnel, and a predicted 50% reduction in metal load from the Solomon Mine, in addition to dilution from treated effluent from the Bulldog Mine in Tier 2. The adopted site-specific standards are intended to set water-quality goals for both segments that reflect the lowest ambient concentrations that are feasible to achieve with the 2013 schedule for redevelopment activities. However, Rio Grande Silver presented evidence that implementation of the Rio Grande Silver Bulldog Mine redevelopment project has been delayed two years. As a result, the Commission extended all of the effective dates and expiration dates by two years.
Rio Grande segments 4a and 7: Ammonia.
The Division and the Town of Creede presented evidence that its wastewater treatment facility has a predicted compliance problem with ammonia effluent limits based on water quality standards in segments 7 and 4a and there is uncertainty regarding the feasibility of meeting the ammonia limits. Creede has submitted a plan to resolve the uncertainty. Based on that plan the Commission adopted a "current conditions" temporary modification to the ammonia standard with an expiration date of 12/31/2018.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-36.38