5 Colo. Code Regs. § 1002-93.12
The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; 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 (303(d) List)
This regulation updates Colorado's List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads ("TMDLs") to reflect additional water quality information available since the Regulation was promulgated in 2006. This list was prepared to fulfill section 303(d) of the federal Clean Water Act ("Act") which requires that states submit to the U.S. Environmental Protection Agency ("EPA") a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.
The "Section 303(d) Listing Methodology - 2008 Listing Cycle" contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority. The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 15, 2007.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2008 Section 303(d) List and the 2008 M&E List. However, this methodology was not adopted by the Commission as a rule. The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
The Commission has considered all existing and readily available information in developing the 2008 Section 303(d) List. In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR § 130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR § 130.7(a)(5)(iii). In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party. The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations. Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as "readily available" for purposes of making the 2008 listing decisions. Such information will be considered in the next listing cycle.
The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources. Priorities of High, Medium and Low were established according to section IV. of the 2008 Section 303(d) Listing Methodology.
Consistent with the 2008 Section 303(d) Listing Methodology, the Division proposed to include 12 segments on the 2008 303(d) List for non-attainment of the aquatic life use due to fish consumption advisories for mercury. The 2008 Section 303(d) Listing Methodology, states:
Fish Consumption Advisories are issued by the Colorado Department of Public Health and Environment ("CDPHE") in instances where analysis of fish tissue samples provides documentation of a public health risk. Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified.
The 2006 303(d) List included three of these reservoirs for impairment due to mercury: one in the Rio Grande basin: Sanchez Reservoir (Rio Grande, segment 30), and two in the San Juan basin: McPhee Reservoir (Dolores, segment 4) and Narraguinnep Reservoir (La Plata, segment 11). These listing were changed by the Commission to specify that the listing was based on non-attainment of the aquatic life. This is consistent with the 2008 Listing Methodology and avoids confusion that there is non-attainment of the mercury standard in the water column.
The Commission has included 12 segments on the 2008 303(d) List for non-attainment of the aquatic life use due to mercury fish consumption advisories for 13 lakes or reservoirs. The Commission also included one listing based on non-attainment of the aquatic life use due to a PCE fish consumption advisory in Willow Springs Ponds, Fountain Creek, segment 7a.
Dissolved Oxygen Standard in Lakes and Reservoirs: The issue of an appropriate D.O. standard in lakes and reservoirs was raised in this hearing by two parties, Northern and the River District. The River District focused its attention to high elevation lakes and reservoirs while Northern discussed the concept of representative data and assessment methods as outlined in the 2008 Listing Methodology. The Division agreed that work is needed to examine the D.O. standard for lakes and reservoirs and that additional refinement of the Listing Methodology is appropriate including consideration of whether and how refugia should be addressed. This standard is scheduled for review in preparation for the 2010 Basic Standards and Methodology, Regulation No. 31, RMH in June 2010. The Commission directs the Division to work with parties in 2008 and 2009 on any changes that are deemed appropriate for the 2010 Listing Methodology. The Commission made listing decisions based on the available data using the adopted standards and the 2008 Listing Methodology. Site-specific decisions made by the Commission are discussed below.
Fountain Creek segment 6, Monument Creek: Mainstem of Monument Creek from the boundary of National Forest Lands to the confluence with Fountain Creek: The Division had proposed retaining the portion of Monument Creek below Mesa Road on the 2008 303(d) List because selenium concentrations in that portion exceed the water quality standard for Fountain Creek Segment 6. The Commission has determined that it is appropriate at this time to include this portion of Monument Creek on the 2008 303(d) List. However, because there is an appropriate plan in place to address the segment as a whole, the Commission directs the Division and Colorado Springs Utilities to revisit this plan to determine the causes and potential reversal of elevated Se concentrations and the appropriate long-term underlying standard for this section of COARFO06.
Lower Colorado segment 2, Colorado River (COLCLC02): Mainstem of the Colorado River from Parachute Creek to the Gunnison River. The Division originally proposed listing this segment based on non-attainment of the selenium standard. The Division based its proposal on data from multiple sampling locations. The River District questioned whether some of the sample locations, including the Humphrey backwater location and others, were in the segment. The Division reviewed the sampling locations and determined that some of the sampling locations used in the original proposal were outside the segment. The segment was reassessed and still showed impairment. The parties disagree whether Humphrey Backwater is located within the segment but agreed that it demonstrated exceedences of the selenium standard. The Commission ultimately decided to list the Humphrey Backwater portion of the Colorado River segment based on those data, rather than listing the entire segment.
White River segment 13b: Shell Frontier Oil and Gas Inc. provided additional analytical results for a number of locations within the Yellow Creek drainage. Re-assessment of several waters which had been proposed for inclusion on the Monitoring and Evaluation List indicated that Corral Creek, Box Elder Gulch, Stake Springs and Duck Creek, are all in attainment of the assigned standard for total recoverable iron. This additional data, however, also demonstrated that the lower portion of Corral Creek and Duck Creek are in non-attainment of the Aquatic Life Use-based chronic selenium standard. The Commission has added these waters to the 303(d) List for selenium.
Upper Colorado segment 5, Wolford Mountain Reservoir (COUCUC05): The River District opposed the Division's proposal to move Wolford Reservoir from the 2006 M&E List to the 2008 303(d) List when no additional data has been collected. In addition, the River District expressed their concerns with the current D.O. standard and Listing Methodology especially as it is applied to high alpine lakes and reservoirs. The Commission moved Wolford Reservoir from the M&E List to the 303(d) List based on the current standards and listing methods. The Commission has encouraged the Division, the River District and other parties to continue to work towards an improved D.O. standard for the 2010 Basic Standards Rulemaking Hearing. The Commission adopted a low priority for this listing, since it is appropriate for the D.O. standard and listing methodology issues to be addressed before substantial resources are expended on development of a TMDL.
Uncompahgre segment 14, Sweitzer Lake (COGUUN14): The Division proposed listing for Sweitzer Lake due to exceedances of the D.O. standard in the mixed layer. The River District pointed out that there was no thermal stratification and adequate refugia present and therefore the segment should not be listed. They also indicated that there is evidence of chemical stratification. The Commission listed Sweitzer Lake, segment COGUUN14, on the 303(d) List due to exceedances in the mixed layer as defined in the Listing Methodology.
Upper Yampa segment 13d, Dry Creek (COUCYA13d): The Division proposed listing the Hubberson Gulch tributary of this segment due to non-attainment of the total recoverable iron standard. Seneca Coal Company (Seneca) provided evidence that the tributary is in attainment of the standard. The Commission did not list the segment for total recoverable iron on the 303(d) List.
Upper Yampa segment 13e, Sage and Grassy Creeks (COUCYA13e): The Division proposed listing this segment due to non-attainment of the total recoverable iron and dissolved selenium standards. Seneca provided evidence that the total recoverable iron standard is attained within the segment. The Commission did not include the segment on the 303(d) List for total recoverable iron. Seneca also provided evidence that the selenium standard is attained in the upper portions of the two creeks in the segment. The Commission did include the lower portion of the creeks (Sage Creek below Routt County Road 51D and Grassy Creek below Routt County Road 27A), on the 303(d) List for dissolved selenium.
BASIS AND PURPOSE (Monitoring and Evaluation List)
This regulation updates Colorado's Monitoring and Evaluation List to reflect additional water quality information available since the Regulation was promulgated in 2006.
The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed.
The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle. Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-93.12