5 Colo. Code Regs. § 1002-93.13
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
Prior to the 2010 listing cycle, Colorado's list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads was set forth in this Regulation #93, and Colorado's Monitoring and Evaluation List was set forth in Regulation #94. In this hearing, the Commission has approved the Division staff proposal to combine both lists into Regulation #93, and to repeal the former Regulation #94. The primary benefit of combining the regulations is to make the status of water segments in Colorado easier to understand by setting forth both lists in one table. This new structure will also make it easier to understand proposed revisions to either list during future rulemaking hearings. These benefits will be seen by the Division, the Commission and interested stakeholders.
Both regulations were heard by the Commission at the same rulemaking hearings in the past and decisions were made for both regulations at the same time. One reason for maintaining separate lists in the past is that Colorado's list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads is subject to EPA approval, while Colorado's Monitoring and Evaluation List is not. Although the Commission is now combining both lists into one regulation for simplicity and ease of use, it will continue to be only the list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads that requires EPA approval. In submitting the revised "Section 303(d) List" to EPA, the Commission will note that only that list is submitted for approval and that the separate Colorado Monitoring and Evaluation List is maintained as state-only information.
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 2008. 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 - 2010 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 11, 2009.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2010 Section 303(d) List and the 2010 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 2010 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 2010 listing decisions. Such information will be considered in the next listing cycle.
In the Division's Quality Management Plan 2007 for the Collection and Utilization of Environmental Data, the WQCD states that "It is the expressed goal of the Division to use only those analytical data that are both reliable and have a defined level of quality." In order to meet this goal, the WQCD required that all information submitted in response to its August 2009 call for data have a certification of quality included with the data. All of the information received for this data call that was utilized to develop assessments for this rulemaking hearing had a quality certification submitted or has been identified as not having this certification. Only a small fraction of the data is not certified.
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 2010 Section 303(d) Listing Methodology.
The 2010 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 Commission has included 17 segments on the 2010 303(d) List for non-attainment of the aquatic life use due to mercury fish consumption advisories for 22 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.
The following segments have been added to the 2010 303(d) List due to new Fish Consumption Advisories:
* Lower Gunnison Segment 4b, Juniata Reservoir
* Lower Colorado Segment 20, Rifle Gap Reservoir
* San Juan Segment 6a, Echo Canyon Reservoir
* Upper Colorado Segment 12, Lake Granby
* Yampa River Segment 2b, Elkhead Reservoir, Catamount Lake
Cadmium and Zinc: As part of the Basic Standards hearing of 2005, new zinc and cadmium table values were adopted. The acute and chronic zinc and cadmium equations in each basin were modified to conform to Regulation No. 31 over the last four years. An increase in cadmium listings were the result of a more stringent cadmium standard.
The following segments were added to the 303(d) List for cadmium:
* Big Thompson Segment 2
* Clear Creek Segments 2a, 2b, 2c, 9b, 11, 13b
* Cache la Poudre Segment 7
* Upper South Platte Segments 2b, 2c, 5a, 5b, 15
* Blue River Segment 12
* Eagle River Segment 5c
* Upper South Platte Segments 3 (Hawkins Gulch), 5a
Temperature: As part of the Temperature Standards hearing of 2007, new temperature table values were adopted. The acute and chronic temperature standards in the Upper and Lower Colorado and the South Platte River Basins were modified to conform to Regulation No. 31 over the last two years.
The following segments were added to the 303(d) List for temperature:
* Upper Colorado Segments 3, 4, 7b and 10c
For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron this value is 300 ug/l. For manganese this value is 50 ug/l. For sulfate this value is 250 ug/l.
The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III. The following segments were proposed for listing based on exceedances of the standards:
* Lower South Platte Segment 1: Manganese
Once a TMDL has been completed, impaired waters are removed from the 303(d) List and placed into Integrated Reporting Category 4a. TMDLs are written to the adopted standards at the time they are submitted to EPA. As standards are periodically reviewed they may become more stringent. In these cases the TMDL may no longer be protective of the current standards. The Division reviewed segments where both TMDLs have been written and new, more restrictive standards have been adopted by the Commission. The Commission has relisted the following segments:
South Platte Basin:
* Clear Creek Segments 09b, 11, and 13b: Cadmium
* Clear Creek Segment 02b: Zinc
* Upper South Platte Segments 2b, 2c and 15: Cadmium
The Division submitted 64 TMDLs to EPA in the last biennium that have been approved. The following segments and parameters have been removed from the 303(d) List:
* Upper Arkansas Segment 2a: Zinc
* Upper Arkansas Segments 2b, 2c and 3: Cadmium and Zinc
* Upper Arkansas Segment 5: Lead and Cadmium
* Upper Arkansas Segment 7: Zinc
* Upper Arkansas Segment 11: pH, Aluminum, Cadmium, Copper and Zinc
* Upper Arkansas Segment 12a: Lead and Zinc
* San Miguel Segment 3a: Zinc
* San Miguel Segment 3b: Cadmium and Zinc
* San Miguel Segments 6a and 6b: Zinc
* Uncompahgre Segments 2, 3a, 6a: Cadmium, Copper, Iron, and Zinc
* Rio Grande Segment 4: Cadmium and Zinc
* Rio Grande Segment 30, Sanchez Reservoir: Aquatic Life Use (Hg FCA)
* Closed Basin Segment 9a: Cadmium
* Closed Basin Segment 9b: Copper
* Dolores River Segment 9: Cadmium and Zinc
* Boulder Creek Segment 4a: pH, Cadmium, Copper and Zinc
* Clear Creek Segment 2: Copper and Zinc
* Clear Creek Segment 3a: Zinc
* Clear Creek Segment 3b: Lead and Zinc
* Clear Creek Segment 9a: Copper
* Clear Creek Segment 9b: Copper, Lead and Zinc
* Clear Creek Segment 11: Lead and Zinc
* Clear Creek Segment 13b: Total Recoverable Iron, Manganese, Zinc, and Aquatic Life Use
* Upper South Platte Segment 4: Copper
* Upper South Platte Segment 5b: Zinc
* Blue River Segment 6: pH, Cadmium, Copper, Lead and Zinc
* Blue River Segment 7: pH, Cadmium, Copper, Lead, Manganese and Zinc
* Blue River Segment 12: Zinc
* Eagle River Segment 5a: Copper and Zinc
* Eagle River Segment 5b: Zinc
* Eagle River Segment 5c: Zinc
* Eagle River Segment 7b: Copper and Zinc
As additional water quality data is collected and assessed, new data may show attainment of the standards. The following segments and parameters have been removed from the 303(d) List due to attainment of current water quality standards:
* Upper Arkansas Segment 2a: NO3
* Uncompahgre River Segment 14, Sweitzer Lake: D.O.
* Lower Colorado Segment 3: Total Recoverable Iron
* White River Segment 13b, Corral Creek: Selenium
* La Plata Segment 4a: Zinc
* Rio Grande Grande Segment 9 (Beaver Creek Reservoir): D.O.
* Closed Basin Segment 6, San Luis Lake: D.O.
* Cherry Creek Segment 2, Cherry Creek Reservoir: chlorophyll a
* Upper Colorado Segment 7a: Total Recoverable Iron
* Yampa River Segment 16: Total Recoverable Iron
* Lower Yampa Segment 20: E. coli
* Cache La Poudre Segment 14 (Horsetooth Reservoir): D.O.
* Upper Colorado Segment 5 (Wolford Reservoir): D.O.
In 2008, the Commission directed the Division to work with outside parties and stakeholders on changes to the Listing Methodology with regards to the assessment of dissolved oxygen in lakes and reservoirs. Refinement of assessment methods were discussed in workgroup meetings and updates to the dissolved oxygen methods were included in the 2010 Listing Methodology.
The revised 2010 Listing Methodology states that if the average temperature in the epilimnion of lakes and reservoirs exceeds the temperature standard, temperature and dissolved oxygen below the epilimnion will be evaluated for adequate refuge. Refuge is defined as the concurrent attainment of the temperature and dissolved oxygen standard at lower depths. If adequate refuge is not present in a single profile, the segment is listed as impaired for dissolved oxygen rather than for temperature. The Commission added the following segments to the 303(d) List due to exceedances of the temperature standard where adequate refuge was not found:
* Lower Arkansas Segment 5b, Trinidad Lake
* Clear Creek Segment 17a, Arvada Reservoir
The Listing Methodology also states that if the average dissolved oxygen concentration in the epilimnion falls below the standard in any profile, the lake will be placed on the 303(d) list. Where the dissolved oxygen standard is not attained in the metalimnion, but it is attained in the epilimnion, the lake may be placed on the M&E list, according to the Listing Methodology. The Commission added 25 new lakes to the M&E list due to exceedances in the dissolved oxygen standard in the metalimnion. The following twelve lakes and reservoirs were added to the 303(d) List due to exceedances in the dissolved oxygen standard in the epilimnion:
* Cache la Poudre Segment 20, Seaman Reservoir
* Middle South Platte Segment 4, Milton Reservoir
* Middle South Platte Segment 7, Prospect Lake
* Upper South Platte Segment 17a, Berkeley Lake, Duck Lake
* Upper South Platte Segment 17b, Sloan's Lake
* Upper South Platte Segment 23, Barnum Lake, Garfield Lake, Harvey Lake, Parkfield Lake and Houston Lake
* Upper Colorado Segment 2, Shadow Mountain Lake
The dissolved oxygen standard is slated for revisions in the 2010 Basic Standards and Methodology, Regulation No. 31, rule-making hearing in June 2010. The attainment decision for these lakes and reservoirs may be different when they are reassessed with the revised standard.
The 2010 Listing Methodology included a provision to allow assessment of the E. coli standard on a seasonal basis. The Division proposed the following segments be placed on the 303(d) List based on seasonal impairments of the E. coli standard:
* Arkansas River Basin, Fountain Creek Segments 2b and 6
* South Platte Basin, Big Thompson Segment 9
* South Platte Basin, Cache la Poudre Segments 12 and 13a
* South Platte Basin, Bear Creek Segment 2
* South Platte, Clear Creek Segment 15
* South Platte, Upper South Platte Segment 16c: Harvard, West Harvard and Lakewood Gulches
The Commission adopted all proposed seasonal listings onto the 303(d) List as proposed by the Division.
The following segments were added to the 303(d) List due to exceedances of water quality standards not identified above:
* South Platte, Bear Creek Segment 5: Swede Gulch/Kerr Gulch, E. coli
* South Platte, Cherry Creek Segment 3: E. coli and Se
* South Platte, Clear Creek Segment 2b: Zn
* South Platte, Clear Creek Segment 3a: Cu
* South Platte, Clear Creek Segment 9a: Silver Creek, Cu and Pb
* South Platte, Clear Creek Segment 9b: pH
* Upper Gunnison Segment 29a, Deadman Gulch: pH, Cd, Cu, Mn, Zn, Fe(Trec)
* Lower Colorado Segment 10: Se
* Lower Colorado, White River Segment 9d: Se
* South Platte, Bear Creek Segment 1c (Bear Creek Reservoir): Chl a, Phosphorus
* South Platte, Bear Creek Segment 5: E. coli
* South Platte, Boulder Creek Segment 2a, 2b and 3: Cu
* South Platte, Boulder Creek Segment 8: Se
* South Platte, Boulder Creek Segment 9: As
* South Platte, Big Thompson Segment 2: Cu, Zn
* South Platte, Big Thompson Segment 3, 6, 7: Cu
* South Platte, Big Thompson Segment 4a, 4b: Se
* South Platte, Big Thompson Segment 8: D.O
* South Platte, Big Thompson Segment 16 (Lake Estes): Cu
* South Platte, Cache La Poudre Segment 7: Pb
* South Platte, Cache La Poudre Segment 11: Se
* South Platte, Lower South Platte Segment 1: Se, Mn
* South Platte, Lower South Platte Segment 2b: Se
* South Platte, Middle South Platte Segment 1a: E. coli
* South Platte, Middle South Platte Segment 1b: Se
* South Platte, Middle South Platte Segment 4 (Barr and Milton Reservoirs): NH3
* South Platte, Middle South Platte Segment 7 (Horse Creek Reservoir and Prospect Lake): pH, NH3
* South Platte, Republican Segment 4: E. coli
* South Platte, St. Vrain Segment 2a: Zn
* South Platte, St. Vrain Segment 4c: Cu, As
* South Platte, Upper South Platte Segment 2c: Zn
* South Platte, Upper South Platte Segment 3 (Hawkins Gulch): Se
* South Platte, Upper South Platte Segment 3 (Horse Creek): D.O., Fe(trec)
* South Platte, Upper South Platte Segment 3 (West Creek): As, Hg
* South Platte, Upper South Platte Segment 3 (Goose Creek): D.O.
* South Platte, Upper South Platte Segment 3 (Trail & Wigwam Creeks): Fe(trec)
* South Platte, Upper South Platte Segment 4: pH
* South Platte, Upper South Platte Segment 5a: Cu, Zn
* South Platte, Upper South Platte Segment 5c: NH3
* South Platte, Upper South Platte Segment 14: As
* South Platte, Upper South Platte Segment 17a (Berkeley Lake): As
* South Platte, Upper South Platte Segment 23 (Barnum Lake): E. coli
* Upper Colorado,Yampa River Segment 13b: Total Recoverable Iron
Metro Wastewater Reclamation submitted a Category 4b Demonstration Plan to the Division for two segments on the mainstem of the South Platte: Upper South Platte Segment 15 and Middle South Platte Segment 1a. Category 4b is an alternative to listing an impaired segment on the 303(d) List. A Category 4b Demonstration Plan, when implemented, must ensure attainment with all applicable water quality standards through pollution control mechanisms within a reasonable time period. This plan was accepted by the U.S. Environmental Protection Agency prior to the development of the Division's proposed 303(d) List. As a result, the Division did not include these segments in their proposal. No further discussion or comments were received by other parties. The Commission did not include Upper South Platte Segment 15 and Middle South Platte Segment 1a on the 303(d) List for ammonia and nitrate, for which the Category 4b Demonstration Plan was written. The Commission expects that after a reasonable period of time as defined in the Category 4b Demonstration Plan, water quality will be reexamined on these segments. If water quality standards are not achieved at this time the segment will be considered impaired and placed on the 303(d) List.
Two proposals were originally submitted in prehearing statements by P.U.R.E. and Wild Earth Guardians to list the South Platte River from Bowles Avenue to the confluence of Sand Creek as impaired for trash. Wild Earth Guardians withdrew their proposal but P.U.R.E maintained their proposal. The Division met prior to the Rulemaking hearing with representatives of P.U.R.E and discussed the issue. The Division maintained that a method to determine impairment for trash did not exist and that this must be determined before a decision of impairment can be made. The Division and P.U.R.E agreed to begin to address this issue in the 2012 303d Listing Methodology development stakeholder process that is to begin in the summer of 2010.
After listening to all of the testimony on this topic, the Commission took no action on listing these segments for trash at this time. It is expected that P.U.R.E, the Division and other stakeholders will work collaboratively to develop an appropriate methodology for determining impairment for trash through the 2012 303d Listing Methodology development process and other appropriate collaborative processes.
The Division proposed to list Muddy Creek (COUCUC07b) on the 303(d) List for temperature. The River Water Conservation District (River District) opposed this listing stating that exceedances at an upper station were due to a temporary construction at the outlet of Wolford Reservoir. Exceedances were still found at the lower station. The Commission adopted the Division's alternate proposal to include the upper portion from Wolford Reservoir to Cow Gulch on the M&E List the and lower portion from Cow Gulch to the Colorado River on the 303(d) List.
The Division proposed to place all of the Colorado River mainstem from Lake Granby to the Roaring Fork River (COUCUC03) on the 303(d) List for temperature exceedances. Northern Colorado River Conservancy District (Northern) proposed an alternative portion of 578 Road bridge to the William Fork confluence. The Commission found that the portion that Northern recommended, omitted sites with exceedances both above and below their recommended portion. To encompass the entire scope of temperature exceedances, the Commission adopted the portion from 578 Road to immediately above the confluence with the Blue River.
In 2008, the Commission adopted only the portion at Humphrey Backwaters Area onto the 303(d) List for selenium. For this cycle, the Division proposed to list the entire segment for selenium. The City of Grand Junction and the River District opposed this listing claiming that the Riverwatch data used in the assessment was not representative or of good quality. The Division supported the quality of this data but since the data was older than five years, the Division agreed that additional data collection was needed before a decision to list the entire segment could be made. The Commission placed the remainder of this segment on the M&E List while leaving the Humphrey Backwaters Area on the 303(d) List. Grand Junction and the River District have offered to collect data throughout the segment before the next 303(d) rulemaking hearing in 2012.
Upper South Platte Segment 16c is an all tributary segment and the Division proposed to place the entire segment on the 303(d) List for exceedances of E. coli and selenium.
E. coli: Denver Environmental Health (DEH) opposed listing all tributaries for both parameters. DEH put forward an alternative proposal for E. coli on this segment with some tributaries to be included on the 303(d) annually, some listed seasonally and one for the M&E List based on the attainment conclusions for each tributary individually. Those tributaries attaining the standard were not proposed for either list. The Division reviewed their proposal and agreed that it is a reasonable approach for E. coli. The Commission adopted the alternative proposal as presented by DEH.
Selenium: DEH also asked that the Commission to only list those tributaries that have selenium data on the 303(d) List. The Division opposed this alternative proposal. The Division pointed out that unlike the data found on E. coli for these tributaries, everywhere that selenium data was collected, exceedances were found. The Commission chose to place the entire segment on the 303(d) List for selenium.
The Division originally proposed to change the E. coli listing on Segment 2a from annual to seasonal (May through October) and to add Segment 2b to the 303(d) List seasonally. Rocky Mountain Environmental Labor Coalition/Sierra Club and Bill Thiebaut, District Attorney for the 10th Judicial District, asked that the listing be considered for the entire year for both segments as there are recreation uses in Fountain Creek year round. Through further investigation and reassessment of the data by the Division and the parties, data indicates that in Segment 2a, the E. coli standards are exceeded annually as opposed to seasonally as originally thought. In Segment 2b the exceedances were only found from May - October. The Commission chose to retain the listing on Segment 2a for E. coli annually and to add Segment 2b to the 303(d) List from May-October.
The Division also originally proposed to remove the selenium listings on Segment 2a and 2b. This proposal also received opposition from RMELC/Sierra Club and Bill Thiebaut as there are ongoing studies regarding selenium in Fountain Creek. Colorado Springs supported the Division's original proposal. Further investigation of acute selenium exceedances in Segment 2b in July 2005 prompted the Division and EPA to change their position prior to the hearing to retain this segment on the 303(d) List. The Commission agreed that this listing should remain on the 303(d) List until further evidence exist to support delisting. The Commission agreed with the Division that the data is meeting the ambient based standards in Segment 2a and removed the M&E listing for that segment.
The Division originally proposed to list only Swede Gulch based on the Division's sampling at the mouth of the gulch. The Bear Creek Watershed Association (BCWA) identified this sampling location as Kerr Gulch. The Division used USGS and other maps indicating this as Swede Gulch. The Colorado Department of Transportation (CDOT) and residents identify this as Kerr Gulch. The Division met with the BCWA and agreed that the watershed, whatever the name of the stream, may be impacted by septic systems and livestock. The BCWA agreed to the development and implementation of a monitoring plan in the watershed to identify E. coli sources. The Division agreed that if the plan were implemented the priority of the listing should be changed from high to low to allow time for sampling and development of stakeholder involvement. The Commission agreed with the Division and the BCWA's plan for Swede Gulch and Kerr Gulch.
The Division proposed to add manganese to the list of impairment parameters of Clear Creek segment 14b. During the 2009 South Platte River Basin RMH a new site-specific manganese standard was established for the segment. In the development of the new site-specific standard for segment 14b, data from both Clear Creek segments 14a and 14b were combined to determine a single standard for both segments. This procedure was used since segment 14a has very limited data and it was felt averaging would establish a more realistic standard. As it turns out when segment 14b only data is assessed against the new standard developed using data from both segments, the few samples from segment 14a with a lower ambient manganese concentration skewed the development of the site-specific standard enough that segment 14b data exceeds the new standard.
Based on the fact that the segment 14b site-specific standard was developed using data from the upstream segment it is not possible to evaluate if the segment is in attainment of the manganese standard. The proper site-specific standard indicating ambient conditions should be equivalent to the current assessment value and would not indicate impairment since they are the same dataset.
After reviewing the development of the segment 14b site-specific manganese standard, the Division agreed with MillerCoors that the Clear Creek segment should not be listed for exceeding the manganese standard. The Commission agreed with the Division and MillerCoors that Clear Creek segment 14b should not be listed for manganese.
The Division originally proposed to list Juniata Reservoir on the 303(d) List for impairment of the Aquatic Life Use due to a Fish Consumption Advisory (FCA). A mercury FCA was issued for Juniata Reservoir in 2009. The Section 303(d) Listing Methodology 2010 Listing Cycle states at III.D.6 "Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified." The City of Grand Junction and Colorado Division of Wildlife proposed to either close the reservoir or change the reservoir to "catch and release" in order for the Division to remove the FCA and therefore remove the basis for inclusion on the 303(d) List. The Division stated that the FCA would not be lifted if the reservoir changed to catch and release and the only way that the FCA could be lifted at Juniata is if the reservoir was completely fenced and fishing access was prohibited. At the time of the hearing, no action had been taken and the FCA was still in effect. Therefore the Commission chose to add this segment to the 303(d) List.
The Division proposed that Marston Reservoir as part of COSPUS22 be placed on the M & E List for non-attainment of the DO standard in the metalimnion. The Denver Water Board argued that Marston was not waters of the state and was not used for aquatic life uses. There was discussion about what constitutes waters of the state and it was decided that that decision was not appropriate for this hearing, since this hearing addresses all waters for which classifications and standards have been adopted. The Commission decided to include Marston Reservoir on the 2010 M & E List because it fits within the description of waters in Upper South Platte segment 22.
This regulation updates Colorado's Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was promulgated in 2008.
See the discussion of list development under subsection B.2 above.
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.
See the discussion of data quality under subsection B.2.c above.
Cadmium and Zinc: As part of the Basic Standards hearing of 2005, new zinc and cadmium table values were adopted. The acute and chronic zinc and cadmium equations in each basin were modified to conform to Regulation No. 31 over the last four years. An increase in cadmium listings were the result of a more stringent cadmium standard.
The following segments were added to the M&E List for cadmium:
* Gunnison River, San Miguel Segment 3a
* South Platte, Boulder Creek Segment 14, Barker Reservoir
* Boulder Creek Segments 2a, 2b, 3, 9 10 and 14
* Clear Creek Segment 6, Hoop Creek
* Cache la Poudre Segment 13a
* Upper South Platte Segment 3, Hawkins Gulch
* Cache La Poudre Segment 9
For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III. For dissolved iron this value is 300 ug/l. For manganese this value is 50 ug/l. For sulfate this value is 250 ug/l.
The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III. The following segments were proposed for listing based on exceedances of the standards:
* Upper Colorado, Yampa River Segments 2a: Manganese
* Upper Colorado, Yampa River Segments 3: Manganese and Dissolved Iron
As additional water quality data is collected and assessed, new data may show attainment of the standards. The following segments and parameters have been removed from the M&E List due to attainment of current water quality standards:
* Fountain Creek Segment 2a: Selenium
* Fountain Creek Segment 3, Bear Creek and Cheyenne Creek: Sediment
* Middle Arkansas Segment 14: E. coli
* Upper Arkansas Segment 5, Turquiose Lake: D.O.
* Upper Arkansas Segment 13: Sediment
* Lower Colorado Segment 4a: Selenium
* Lower Colorado Segment 11h: Total Recoverable Iron
* Lower Colorado Segment 13b: D.O. and E. coli
* St. Vrain Segment 2: Sediment
* St. Vrain Segment 3: E. coli
* Upper South Platte Segment 2a: Sediment
* Upper South Platte Segment 3: Sediment and Temperature
* Upper South Platte Segment 4 (North Fork South Platte and Buffalo Creek): Sediment
* Upper South Platte Segment 6a: Sediment
* Upper Colorado, Yampa River Segment 3 (First Creek): Sediment
* Upper Colorado, Yampa River Segment 19 (Oliver Creek): Sediment
* Upper Colorado, North Platte River Segment 4a: Sediment
* Gunnison River, Uncompahgre Segment 3b, Ridgway Reservoir: D.O.
* Gunnison River, San Miguel Segment 7a: Total Recoverable Iron
* Lower Colorado, White River Segment 22: Sediment
* Upper Colorado, Blue River Segment 18: E. coli
As additional water quality data is collected and assessed, a segment may be moved from the M&E List to the 303(d) List once the non-attainment is confirmed. In general, segments with less than 10 data points will be placed on the M&E List until more data is collected. The following segments and parameters have been moved from the M&E List to the 303(d) List due to additional data collection:
* Lower Arkansas Segment 5b: D.O.
* San Miguel Segment 3a: Cadmium
* Upper Gunnison Segment 29a, Deadman Gulch: Cd, Cu, Mn, Zn, Fe(Trec)
* Big Thompson Segment 4b: Selenium
* Boulder Creek Segment 8: Selenium
* Upper Colorado Segment 12, Shadow Mountain Lake: D.O.
* Upper Colorado, Yampa River Segment 3 (Bushy Creek): Sediment
* Upper South Platte 5a: Cadmium, copper and zinc
In 2008 the Commission directed the Division to work with parties in 2008 and 2009 on changes to the Listing Methodology in regards to dissolved oxygen. Refinement of assessment methods were discussed in workgroup meetings and included in the 2010 Listing Methodology. The dissolved oxygen standard is slated for revisions in the 2010 Basic Standards and Methodology, Regulation No. 31, RMH in June 2010.
The following segments were added to the M&E List due to exceedances of the dissolved oxygen standard in the metalimnion in at least one profile:
* Gunnison River, Uncompahgre Segment 14, Sweitzer Lake
* Rio Grande Segment 9, Beaver Creek Reservoir
* Big Dry Creek Segment 2, Standley Lake
* Boulder Creek Segment 14, Barker Reservoir
* Big Thompson Segment 12, Lake Loveland, Horseshoe Lake and Boyd Lake
* Big Thompson Segment 14, Lon Hagler Reservoir and Lonetree Reservoir
* Cache la Poudre Segment 14, Horsetooth Reservoir
* Lower South Platte Segment 3, North Sterling Reservoir
* Middle South Platte Segment 4, Barr Lake
* Middle South Platte Segment 7, Horse Creek Reservoir
* St. Vrain Creek Segment 7, Boulder Reservoir
* St. Vrain Segment 9, Union Reservoir
* St. Vrain Segment 13, Lake Thomas
* Upper South Platte Segment 16b, Aurora Reservoir
* Upper South Platte Segment 19, Tarryall Reservoir, Cheesman Reservoir, Elevenmile Reservoir, Spinney Mountain Reservoir
* Upper South Platte Segment 22, Marston Reservoir, Quincy Reservoir,
* Upper South Platte Segment 23, Vanderbilt Reservoir
* Upper Colorado Segment 5, Wolford Mountain Reservoir
* Upper Colorado, Yampa River Segment 2b, Stagecoach Reservoir
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-93.13