5 Colo. Code Regs. § 1002-38.63
As a result of this hearing, the Commission adopted a temporary modification of "existing quality" for the Wapiti Meadows Wetlands portion of segment 2 of the Big Thompson River. The temporary modification is for dissolved oxygen, e. coli, ammonia, nitrate, boron, cadmium, copper, lead, mercury, nickel, selenium, silver and zinc and expire on 12/31/2009. Upper Thompson Sanitation District's (UTSD) effluent provides essentially the entire flow to the wetland. The existing quality is thus defined as the historical quality of the UTSD discharge to Wapiti Wetlands. For the purposes of permitting during the course of the temporary modification, existing quality means continuation of current UTSD effluent quality.
This temporary modification is based upon uncertainty regarding the appropriate underlying standards needed to protect the water quality dependant functions of the wetland. The temporary modification recognizes current conditions and allows time for the UTSD and others to conduct a study of the existing wetland and determine appropriate attainable ambient-based numeric standards to protect the wetland, and to evaluate the water quality dependant functions of the wetland, including flood flow alteration/sedimentation, toxic materials retention, nutrient removal, wildlife diversity and abundance, ground water recharge and recreation. A study plan, which was jointly developed by the UTSD, the Division, the Bureau of Reclamation, and EPA, was submitted to the Commission.
The results of the study could also become the basis for adopting a site-specific wetlands use classification as provided for in section 31.13 of The Basic Standards and Methodologies For Surface Water (Regulation 31). The Commission anticipates that this option will be considered at the time underlying standards for this segment are reviewed by the Commission.
PARTIES TO THE RULEMAKING
5 CCR 1002-38.63