Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-93 - REGULATION NO. 93 - COLORADO'S SECTION 303(D) LIST OF IMPAIRED WATERS AND MONITORING AND EVALUATION LIST
Section 5 CCR 1002-93.14 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER 2011 RULEMAKING, EFFECTIVE DATE OF MARCH 30, 2012
Current through Register Vol. 47, No. 17, September 10, 2024
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
A. Revisions to 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 revised in 2010. 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.
This regulation also updates Colorado's Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was revised in 2010.
The "Section 303(d) Listing Methodology - 2012 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 in March 2011.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2012 Section 303(d) List and the 2012 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 2012 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 2012 listing decisions. Such information will be considered in the next listing cycle.
In the Water Quality Control Division's (WQCD) Quality Management Plan 2011 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."
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 2012 Section 303(d) Listing Methodology.
The Division remains committed to establishing a plan for monitoring and evaluating water bodies on the M&E List 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.
The 303(d) Listing Methodology was revised in 2012 for the assessment of Fish Mercury (Hg). The newly adopted methods compare the median fish Hg for each waterbody and species to a 0.3 ppm threshold. A sample size requirement of 30 fish tissue samples per waterbody/species was also introduced in order to list new waterbodies for Fish Hg. Waterbodies can also be listed if there is overwhelming evidence of impairment (>0.45 ppm Hg) and a sample size of at least 10 fish tissue samples.
The Commission retained the following 6 lakes on the 303(d) List because these lakes have a median Hg above the 0.3 ppm threshold and either meet the sample size requirements or show overwhelming evidence of impairment:
* Upper South Platte Segment 23, Berkeley Lake (COSPUS23)
* Upper Arkansas Segment 27, Brush Hollow Reservoir (COARUA27)
* Cache la Poudre Segment 14, Horsetooth Reservoir (COSPCP14)
* Upper South Platte Segment 17a, Rocky Mountain Lake (COSPUS17a)
* Lower Arkansas Segment 5b, Trinidad Reservoir (COARLA05b)
* Los Pinos Segment 3, Vallecito Reservoir (COSJPN03)
The Commission retained the following 10 lakes on the 303(d) List because they were on the 303(d) List prior and have a median Hg of greater than 0.3 ppm. Although the 2012 Listing Methodology requires a minimum sample size of thirty fish, the Commission chose to retain these segments on the 303(d) List as opposed to the Monitoring and Evaluation List:
* Big Thompson Segment 11, Carter Reservoir (COSPBT11)
* Yampa River Segment 2b, Catamount Reservoir (COUCYA02b)
* San Juan Segment 6a, Echo Canyon Reservoir (COSJSJ06a)
* Yampa River Segment 2b, Elkhead Reservoir (COUCYA02b)
* Middle Arkansas Segment 16, Horseshoe Lake- Lathrop (COARMA16)
* Dolores River Segment 4, McPhee Reservoir (COSJDO04)
* Los Pinos, Segment 11, Narraguinnep Reservoir (COSJLP11)
* Lower Colorado Segment 20, Rifle Gap Reservoir (COLCLC20)
* La Plata Segment 11, Totten Reservoir (COSJLP11)
* Upper Arkansas Segment 14b, Teller Reservoir (COARUA14b)
The Commission retained the following 2 lakes on the 303(d) List because they were on the 303(d) List prior to the adoption of the new assessment methods. With median Fish Hg concentrations below 0.3 ppm, they will not be removed from the 303(d) List, however, until a minimum of 30 fish are collected:
* Big Thompson Segment 12, Boyd Lake (COSPBT12)
* Upper Colorado Segment 12, Lake Granby (COUCUC12)
The Commission added the following 3 lakes on the Monitoring and Evaluation List because they have a median Fish Hg of greater than 0.3 ppm but the sample size is insufficient for Listing:
* North Platte Segment 4a, Big Creek Lake (COUCNP04a)
* Boulder Segment 15, Gross Reservoir (COSPBO15)
* Big Thompson Segment 14, Lonetree Reservoir (COSPBT14)
The Commission removed the following lake from the 303(d) List. Additional data was collected meeting the minimum sample size requirement of thirty fish. Median Fish Hg concentrations are below the 0.3 ppm, threshold.
* Lower Gunnison Segment 4, Juniata Reservoir (COGULG04)
The Commission retained 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 segment was 303(d) listed for non-attainment of the Aquatic Life Use based on Policy 10-1:
* White River, Segment 13c, Yellow Creek (COLCWH13c)
The following segments were provisionally 303(d) listed for non-attainment of their Aquatic Life Use based on Policy 10-1:
* Upper Arkansas Segment 21a, Cripple Creek (COARUA21a)
* San Miguel Segment 12, Maverick Draw (COGUSM12)
* Upper Gunnison Segment 6b, Cement Creek (COGUUG06b)
* Upper Gunnison Segment 15, S. Beaver Creek (COGUUG15)
* Upper Gunnison Segment 24, Cochetopa Creek from Forest Road 3076/Co. Rd 43 to confluence with Tomichi Creek (COGUUG24)
* Upper Gunnison Segment 29a, Lake Fork Gunnison River between Cooper and Silver Creek (COGUUG29a)
* Uncompahgre Segment 11, Deer Creek (COGUUN11)
* Lower Yampa Segment 22a, Talamantes Creek COLCLY22a)
* White River Segment 15, Piceance Creek (COLCWH15)
* White River Segment 20, Black Sulphur Creek (COLCWH20)
* White River Segment 23, West Douglas Creek (COLCWH23)
* Rio Grande Segment 12, Rio Grande River (CORGRG12)
* Bear Creek Segment 1a, Bear Creek from Witter Gulch to inlet to Evergreen Lake (COSPBE01a)
* Boulder Creek Segment 9, Boulder Creek from 107th Street to confluence with Coal Creek (COSPBO09)
* Clear Creek Segment 14a, Clear Creek from Croke Canal diversion to McIntyre Street (COSPCL14a)
* St. Vrain Segment 3, St. Vrain Creek (COSPSV03), from Left Hand Creek confluence to confluence with Boulder Creek
* Upper South Platte Segment 3, Horse Creek (COSPUS03)
* Upper South Platte Segment 10a, West Plum Creek (COSPUS10a)
* Upper South Platte Segment 11a, Cook Creek (COSPUS11a)
* Eagle River Segment 6, Lake Creek (from below the confluence with East and West Lake Creek to the mouth), and Red Sandstone Creek (from north side I-70 Frontage Road to the confluence with Gore Creek) (COUCEA06)
* Eagle River Segment 8, Gore Creek (COUCEA08)
* Roaring Fork Segment 3a, Roaring Fork from Hunter Creek to Brush Creek confluence, Cattle Creek from Bowers Gulch to Mouth, W. Sopris Creek (COUCRF03a)
* Roaring Fork Segment 4, Brush Creek (COUCRF04)
* Roaring Fork Segment 7, South Fork Frying Pan River from transbasin diversion to confluence with unnamed tributary (COUCRF07)
* Upper Colorado Segment 10a, Fraser River, Vasquez Creek (COUCUC10a)
* Yampa River Segment 15, Elkhead Creek (COUCYA15)
The following segments were included on the M&E List for possible non-attainment of their Aquatic Life Use based on Policy 10-1:
* Bear Creek Segment 1e, Bear Creek (COSPBE01e)
* White River Segment 13b, Duck Creek (COLCWH13b)
* Eagle River Segment 6, Black Gore Creek Beaver Creek (from Wayne Creek to Mouth), Red Sandstone Creek (from USFS boundary to north side I-70 Frontage Road) (COUCEA06)
* Eagle River Segment 9a, Eagle River (from confluence with Berry Creek to confluence with Squaw Creek) (COUCEA09a)
Several segments were found to have data outside of the standard index period for data collection. The Commission included these segments on the Monitoring and Evaluation (M&E) List in order to gather more information within the standard index period. The following segments were listed on the M&E List for possible non-attainment of their Aquatic Life Use based on Policy 10-1:
* Fountain Creek Segment 4, Sand Creek (COARFO04)
* Upper Arkansas Segment 5, Lake Fork Creek (COARUA05)
* Upper Gunnison Segment 8, Slate River (COGUUG08)
* Saint Vrain Segment 3, Saint Vrain Creek from Hover Road to the confluence with Left Hand Creek (COSPSV03)
* Boulder Creek Segment 7b, Coal Creek (COSPBO07b)
* Bear Creek Segment 2, Bear Creek (COSPBE02)
* Clear Creek Segment 1, Kearney Gulch, Grizzly Gulch (COSPCL01)
Various parties questioned whether or not the data collected below reservoirs should be evaluated as being representative of an entire stream segment. They recommend that listings below reservoirs be placed on the M&E List while the applicability of the current thresholds below reservoirs is investigated. The Division agreed that a study was warranted and changed its proposal to the M&E List. The Commission placed the following segments on the M&E List for possible non-attainment of their Aquatic Life Use:
* COUCBL17, Blue River from outlet of Dillon Reservoir to N. Rock Creek confluence
* COARUA05, Lake Fork below Sugarloaf Dam
* COSPUS02a, South Fork South Platte River below Antero
* COSPUS06a, South Platte River below Cheesman at Cheesman Canyon
* COSPUS03, Trout Creek below Manitou Reservoir Dam
* COUCUC03, Colorado River from below Windy Gap Reservoir to FR 538
Several segments were found to have data outside of the assessed period of record. Therefore, the Division proposed to remove them from both the 303(d) and M&E Lists. The Commission did not include these segments on either list:
* Upper Arkansas Segment 5, S. Cottonwood Creek (COARUA05)
* Upper Arkansas Segment 18, Currant Creek (COARUA18)
* San Miguel Segment 2, Howard Fork (COGUSM02)
* Rio Grande Segment 2, South Clear Creek (CORGRG02)
* Animas and Florida Segment 13c, Salt Creek (COSJAF13c)
* Big Thompson Segment 2, Big Thompson River (COSPBT02)
* Blue River Segment 17, Blue River from N. Rock Creek confluence to Colorado River (COUCBL17)
* North Platte Segment 4a, Snyder Creek (COUCNP04a)
* Upper Colorado Segment 7a, Big Alkali Creek (COUCUC07a)
Other issues were raised in this rulemaking hearing in regards to listing decisions based on the assessment of macroinvertebrate data. In October 2010, the Commission adopted the Aquatic Life Use Attainment WQCC Policy 2010-1 which determined that the Colorado MMI is an appropriate tool for the quantitative bioassessment of the health of aquatic communities. The Commission adopted the 2012 Listing Methodology in March 2011. This Regulation No. 93 rulemaking hearing is the first occasion where the policies adopted by the Commission in Policy 2010-1 are being implemented into regulation. The Division followed the policies as defined in the methodologies to the intent for which they were adopted. The Commission recognizes that some of the policy decisions that were questioned by various parties may need additional review. The Commission directs the Division and interested parties to review WQCC Policy 2010-1 and the 2012 Listing Methodology and make appropriate changes in regards to the use of data for the MMI tool.
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 mg/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 included on the 303(d) listing based on exceedances of the standards:
* Lower Gunnison Segment 4a, Whitewater Creek from below Brandon Ditch to confluence with Gunnison River: Manganese, Sulfate (COGULG04a)
* North Fork Segment 6b, Alum Gulch: Sulfate (COGUNF06b)
* Upper Gunnison Segment 11, Coal Creek: Manganese (COGUUG11)
* Upper Gunnison Segment 29a, Lake Fork Gunnison River: Manganese (COGUUG29a)
* Upper Gunnison Segment 32, N. Fork Henson Creek: Manganese (COGUUG32)
* Uncompahgre Segment 2, Uncompahgre River: Manganese (COGUUN02)
* Animas and Florida Segment 5a, Animas River: Manganese (COSJAF05a)
* La Plata Segment 4a, E. Mancos River, Manganese (COSJLP04a)
* Big Thompson Segment 8, Little Thompson River: Sulfate (COSPBT08)
* Clear Creek Segment 15, Clear Creek: Manganese (COSPCL15)
* Saint Vrain Segment 5, Left Hand Creek: Manganese (COSPSV05)
* Blue River Segment 2a, Blue River: Manganese (COUCBL02a)
* Upper Colorado Segment 3, Colorado River: Manganese (COUCUC03)
The following segments were included on the M&E List:
* Lower Gunnison Segment 4a, Callow Creek, Cummings Gulch, Peach Valley Creek: Sulfate (COGULG04a)
* Lower Gunnison Segment 4b, Kannah Creek: Sulfate (COGULG04b)
* North Fork Segment 6b, Cottonwood Creek: Manganese, Sulfate (COGUNF06b)
* San Miguel Segment 8, S. Fork San Miguel River: Manganese (COGUSM08)
* Upper Gunnison Segment 15, S. Beaver Creek: Manganese, Dissolved Iron (COGUUG15)
* Upper Gunnison Segment 17, Antelope Creek: Manganese (COGUUG17)
* Upper Gunnison Segment 23, Cochetopa Creek: Dissolved Iron (COGUUG23)
* Uncompahgre Segment 11, Cow Creek: Sulfate (COGUUN11)
* Piedra River Segment 6a, Stollsteimer Creek: Sulfate (COSJPI06a)
The Division submitted 26 TMDLs to EPA in the last biennium that have been approved. The following segments and parameters have been removed from the 303(d) List:
* Arkansas, Upper Arkansas Segment 10, Lake Creek: Cu (COARUA10)
* Gunnison, Lower Gunnison Segment 2, Gunnison River: Se (COGULG02)
* Gunnison, Lower Gunnison Segment 4a, Tributaries to Gunnison River: Se (COGULG04a)
* Gunnison, Lower Gunnison Segment 4c, Red Rock Creek: Se (COGULG04c)
* Gunnison, North Fork Segment 3, North Fork Gunnison River: Se (COGUNF03)
* Gunnison, North Fork Segment 5, Leroux Creek, Jay Creek: Se (COGUNF05)
* Gunnison, North Fork Segment 6a, Short Draw: Se (COGUNF06a)
* Gunnison, North Fork Segment 6b, Big Gulch, Cottonwood Creek: Se (COGUNF06b)
* Gunnison, San Miguel Segment 3a, San Miguel River: Cd (COGUSM03a)
* Gunnison, San Miguel Segment 6a, Ingram Creek: Cd (COGUSM06a)
* Gunnison, San Miguel Segment 6b, Marshall Creek: Cd (COGUSM06b)
* Gunnison, Upper Gunnison Segment 30, Henson Creek: Cd, Zn(sc) (COGUUG30)
* Gunnison, Upper Gunnison Segment 31, Palmetto Gulch: Cd, Zn (COGUUG31)
* Gunnison, Uncompahgre Segment 4b, Uncompahgre River: Se (COGUUN04b)
* Gunnison, Uncompahgre Segment 4c, Uncompahgre River: Se (COGUUN04c)
* Gunnison, Uncompahgre Segment 12, Tributaries to Uncompahgre River: Se (COGUUN12)
* South Platte, Boulder Segment 2b, Boulder Creek from 13th Street to the confluence with South Boulder Creek: E. coli (COSPBO02b)
* South Platte, Boulder Segment 4a, Gamble Gulch: Cd (COSPBO04a)
* South Platte, Upper South Platte Segment 5a, Geneva Creek: Cd, Cu, Zn (COSPUS05a)
* South Platte, Upper South Platte Segment 5b, Geneva Creek: Cd (COSPUS05b)
* South Platte, Upper South Platte Segment 15, South Platte River: Cd (COSPUS15)
* Upper Colorado, Blue River Segment 12, Illinois Gulch: Cd (COUCBL12)
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:
* Arkansas, Fountain Creek Segment 1a, Fountain Creek: Se (COARFO01a)
* Arkansas, Fountain Creek Segment 2b, Fountain Creek: Se (COARFO02b)
* Arkansas, Fountain Creek Segment 6, Monument Creek below Mesa Road: Se (COARFO06)
* Arkansas, Lower Arkansas Segment 4, Lorencito Canyon: Se (COARLA04)
* Arkansas, Lower Arkansas Segment 5a, Purgatoire River: Se (COARLA05a)
* Gunnison, Lower Dolores Segment 1, Dolores River: Fe(Trec) (COGULD01)
* Gunnison, Lower Gunnison Segment 2, Gunnison River: SO4 (COGULG02)
* Gunnison, Lower Gunnison Segment 8, Kannah Creek: Se (COGULG08)
* Gunnison, Upper Gunnison Segment 11, Coal Creek: Pb (COGUUG11)
* Lower Colorado, Lower Colorado Segment 3, Colorado River mainstem: Se (COLCLC03)
* South Platte, Middle South Platte Segment 4, Barr Lake: NH3 (COSPMS04)
* South Platte, Upper South Platte Segment 23, Barnum Lake: E. coli (COSPUS23)
The following segments and parameters have been removed from the M&E List due to attainment of current water quality standards:
* Arkansas, Upper Arkansas Segment 20, North Fork Wilson Creek: Cu (COARUA20)
* Arkansas, Upper Arkansas Segment 27, Brush Hollow Reservoir: pH (COARUA27)
* Gunnison, Lower Gunnison Segment 7, Surface Creek: Fe(Trec) (COGULG07)
* Gunnison, Lower Gunnison Segment 7, Ward Creek: Se (COGULG07)
* Gunnison, San Miguel Segment 2, Bilk Creek: Cd (COGUSM02)
* Gunnison, Upper Gunnison Segment 7, Slate River: Cd (COGUUG07)
* Gunnison, Upper Gunnison Segment 16, Ohio Creek: Zn(sculpin) (COGUUG16)
* Upper Gunnison Segment 17, Antelope Creek: Dissolved Oxygen (COGUUG17)
* Gunnison, Upper Gunnison Segment 18, Tomichi Creek: E. coli (COGUUG18)
* Gunnison, Upper Gunnison Segment 32, N. Fork Henson Creek: Pb, Zn(sculpin) (COGUUG32)
* Gunnison, Uncompahgre Segment 8, Mineral Creek: Cd (COGUUN08)
* Lower Colorado, Lower Colorado Segment 2b, Colorado River mainstem: Se (COLCLC02b)
* Rio Grande, Alamosa Segment 11, La Jara Reservoir: Cu, Se, Zn (CORGAL11)
* South Platte, Big Thompson Segment 11, Carter Lake: Cu (COSPBT11)
* South Platte, Big Thompson Segment 16, Lake Estes: As (COSPBT16)
* South Platte, Cache la Poudre Segment 14, Horsetooth Reservoir: D.O. (COSPCP14)
* South Platte, Lower South Platte Segment 3, N. Sterling and Jumbo Reservoirs: pH (COSPLS03)
Twenty-eight lakes were previously on the M&E List due to low dissolved oxygen (DO) in the metalimnion. With the adoption of a revised DO standard in 2011, the Division proposed to remove 24 of these lakes from the M&E list because the lakes are now in attainment. Barr Lake was proposed for the 303(d) List for DO because recent data show non-attainment. The Division proposed that Horse Creek Reservoir, North Sterling Reservoir and Lake Thomas remain on the M&E list for DO either because of a minimal sample size (n=1) or due to concerns of the representative nature of the data. The Commission supported the Division's proposal.
Lakes now in attainment with the revised DO standard:
* Upper South Platte Segment 16b, Aurora Reservoir (COSPUS16b)
* Boulder Segment 14, Barker Reservoir (COSPBO14)
* Bear Creek Segment 1c, Bear Creek (COSPBE01C)
* Rio Grande Segment 9, Beaver Creek Reservoir (CORGRG09)
* St. Vrain Segment 7, Boulder Reservoir (COSPSV07)
* Big Thompson Segment 12, Boyd Lake (COSPBT12)
* Upper South Platte Segment 19, Cheesman Reservoir (COSPUS19)
* Cherry Creek Segment 2, Cherry Creek Reservoir (COSPCH02)
* Upper South Platte Segment 19, Elevenmile Reservoir (COSPUS19)
* Big Thompson Segment 12, Horseshoe (Loveland) Lake (COSPBT12)
* Cache la Poudre Segment 14, Horsetooth Reservoir (COSPCP14)
* Big Thompson Segment 14, Lon Hagler Reservoir (COSPBT14)
* Big Thompson Segment 14, Lonetree Reservoir (COSPBT14)
* Big Thompson Segment 12, Lake Loveland (COSPBT12)
* Upper South Platte Segment 22, Marston Reservoir (COSPUS22) - Now identified as Bear Creek Segment 11 (COSPBE11)
* Upper South Platte Segment 16c, Quincy Reservoir (COSPUS16c)
* Upper South Platte Segment 19, Spinney Mountain Reservoir (COSPUS19)
* Yampa River Segment 2b, Stagecoach Reservoir (COUCYA02b)
* Big Dry Segment 2, Standley Lake (COSPBD02)
* Uncompahgre River Segment 14, Sweitzer Reservoir (COGUUN14)
* Upper South Platte Segment 2a, Tarryall Reservoir (COSPUS02a)
* St. Vrain Segment 9, Union Reservoir (COSPSV09)
* Upper South Platte Segment 23, Vanderbilt Lake, Harvey Lake, Duck Lake (COSPUS23)
* Upper Colorado Segment 5, Wolford Mountain Reservoir (COUCUC05)
The Commission moved the following lakes to the 303(d) List for D.O.:
* Middle South Platte Segment 4, Barr Lake (COSPMS04)
* Middle South Platte Segment 7, Horse Creek Reservoir (COSPMS07)
* Upper South Platte Segment 23, Vanderbilt Lake (COSPUS23)
The Commission retained the following lakes on the M&E List for D.O.:
* Lower South Platte Segment 3, North Sterling Reservoir (COSPLS03)
* St. Vrain Segment 7, Thomas Reservoir (COSPSV07)
The following segments or parameters were added to the 303(d) List due to exceedances of water quality standards not identified above:
* Arkansas, Upper Arkansas Segment 20, North Fork Wilson Creek: As (COARUA20)
* Gunnison River, Lower Gunnison Segment 3, Eggleston Reservoir: Fe(Trec) (COGULG03)
* Gunnison River, Lower Gunnison Segment 7, Tongue Creek: Fe(Trec) (COGULG07)
* Gunnison River, Lower Gunnison Segment 13, Crawford Reservoir: D.O. (temperature) (COGULG13)
* Gunnison River, North Fork Gunnison Segment 4, East Muddy Creek: Fe(Trec) (COGUNF04)
* Gunnison River, North Fork Gunnison Segment 6b, Alum Gulch: SO 4 , Fe(Trec) (COGUNF06b)
* Gunnison River, San Miguel Segment 2, Bear Creek: Cd, Zn(sc) (COGUSM02)
* Gunnison River, San Miguel Segment 2, Howard Fork abv Swamp Gulch: pH, D.O. (COGUSM02)
* Gunnison River, San Miguel Segment 11, Miramonte Reservoir: D.O. (temperature) (COGUSM11)
* Gunnison River, Upper Gunnison Segment 9, Coal Creek: As (COGUUG09)
* Gunnison River, Upper Gunnison Segment 11, Elk Creek: As (COGUUG11)
* Gunnison River, Upper Gunnison Segment 11, Coal Creek: Cd, Zn, As (COGUUG11)
* Gunnison River, Upper Gunnison Segment 12, Coal Creek: Cu (COGUUG12)
* Gunnison River, Upper Gunnison Segment 26, Blue Creek: Cu (COGUUG26)
* Gunnison River, Uncompahgre Segment 4c, Uncompahgre River: Fe(Trec) (COGUUN04c)
* Gunnison River, Uncompahgre Segment 6a, Red Mountain Creek: Ag, Cu (COGUUN06a)
* Gunnison River, Uncompahgre Segment 7, Gray Copper Gulch: Cu (COGUUN007)
* Gunnison River, Uncompahgre Segment 9, Sneffels Creek: Cd, (COGUUN09)
* Gunnison River, Uncompahgre Segment 12, Dry Creek: Fe(Trec) (COGUUN12)
* Gunnison River, Uncompahgre Segment 12, Loutzenhizer Arroyo: Fe(Trec) (COGUUN12)
* Gunnison River, Lower Dolores Segment 5, Roc Creek: Cu, Fe(Trec) (COGULD05)
* Lower Colorado, Lower Colorado Segment 13b, Leach Creek: E. coli, Fe(Trec) (COLCLC013b)
* Lower Colorado, White River Segment 13c, Yellow Creek: Fe(Trec) (COLCWH13c)
* Lower Colorado, White River Segment 14a, Piceance Creek from Willow Creek to Hunter Creek: Fe(Trec) (COLCWH14a)
* San Juan/Dolores Rivers, Animas and Florida Segment 3c, Arrastra Gulch: Cd, Zn COSJAF03c)
* San Juan/Dolores Rivers, Animas and Florida Segment 4a, Animas River: Al(Trec) (COSJAF04a)
* San Juan/Dolores Rivers, La Plata Segment 1, La Plata River: Ag (COSJLP01)
* San Juan/Dolores Rivers, La Plata Segment 4a, E. Mancos River: D.O. (COSJLP04a)
* San Juan/Dolores Rivers, La Plata Segment 4a, Mancos River: D.O. (COSJLP04a)
* San Juan/Dolores Rivers, La Plata Segment 7a, McElmo Creek: Fe(Trec), E. coli (COSJLP07a)
* San Juan/Dolores Rivers, La Plata Segment 8a, Mud Creek: Se (COSJLP08a)
* San Juan/Dolores Rivers, La Plata Segment 8a, Trail Canyon: Fe(Trec) (COSJLP08a)
* San Juan/Dolores Rivers, San Juan Segment 6a, Echo Canyon Reservoir: DO (Temperature) (COSJSJ06a)
* South Platte, Bear Creek Segment 1a, Bear Creek: Temperature (COSPBE01a)
* South Platte, Bear Creek Segment 1e, Bear Creek: Temperature (COSPBE01e)
* South Platte, Cherry Creek Segment 3, Cherry Creek: Fe(Trec) (COSPCH03)
* South Platte, Clear Creek Segment 17b, Ralston Creek: U (COSPCL17b)
* South Platte, Upper South Platte Segment 17a, Smith Lake: NH3 (COSPUS17a)
* South Platte, St. Vrain River Segment 5, Left Hand Creek: Cu (COSPSV05)
* Upper Colorado, Eagle River Segment 9a, Eagle River from Ute Creek to Rube Creek: Temperature (COUCEA09a)
* Upper Colorado, Eagle River Segment 9a, Eagle River from Berry Creek to Squaw Creek: Sediment (COUCEA09a)
* Upper Colorado, North Platte Segment 9, Lake John: D.O. (COUCNP09)
* Upper Colorado, Upper Colorado Segment 2, Willow Creek Reservoir: Mn (COUCUC02)
The following segments or parameters were added to the M&E List where there is a reason to suspect water quality problems, but there is also uncertainty.:
* Arkansas River, Fountain Creek Segment 2a, Fountain Creek: Fe(Trec)
* Gunnison River, Lower Gunnison Segment 3, Eggleston Reservoir: pH, Zn, Fe(Trec) (COGULG03)
* Gunnison River, Lower Gunnison Segment 4a, Callow Creek: E. coli (COGULG04a)
* Gunnison River, Lower Gunnison Segment 4a, Peach Valley Creek: Fe(Trec) (COGULG04a)
* Gunnison River, Lower Gunnison Segment 4a, Wells Gulch: pH (COGULG04a)
* Gunnison River, Lower Gunnison Segment 7, Ward Creek: Se (COGULG07)
* Gunnison River, Lower Gunnison Segment 7, Surface Creek: Pb (COGULG07)
* Gunnison River, Lower Gunnison Segment 12, Muddy Creek: E. coli (COGULG12)
* Gunnison River, North Fork Gunnison Segment 4, East Muddy Creek: Pb, Se (COGUNF04)
* Gunnison River, North Fork Gunnison Segment 4, Muddy Creek: E. coli (May-Oct) (COGUNF04)
* Gunnison River, North Fork Gunnison Segment 4, Island Reservoir: pH, Zn (COGUNF04)
* Gunnison River, North Fork Gunnison Segment 5, Leroux Creek: E. coli (COGUNF05)
* Gunnison River, North Fork Gunnison Segment 6a, Unnamed Tributary: Se (COGUNF06a)
* Gunnison River, North Fork Gunnison Segment 6b, Alum Gulch: Fe(Trec) (COGUNF06b)
* Gunnison River, North Fork Gunnison Segment 7, Paonia Reservoir: Zn (COGUNF07)
* Gunnison River, San Miguel Segment 2, Bear Creek: Pb (COGUSM02)
* Gunnison River, San Miguel Segment 2, Cornet Creek: Pb (COGUSM02)
* Gunnison River, San Miguel Segment 3b, San Miguel River: Pb (COGUSM03b)
* Gunnison River, San Miguel Segment 4a, San Miguel River: Pb (COGUSM04a)
* Gunnison River, San Miguel Segment 7a, Chapman Creek: Fe(Trec) (COGUSM07a)
* Gunnison River, San Miguel Segment 7a, Iron Bog Creek: pH, D.O. (COGUSM07a)
* Gunnison River, San Miguel Segment 10, Naturita Creek: E. coli, D.O. (COGUSM10)
* Gunnison River, San Miguel Segment 12, Mesa Creek: Se (COGUSM12)
* Gunnison River, San Miguel Segment 12, Calamity Draw: D.O. (COGUSM12)
* Gunnison River, San Miguel Segment 12, Specie Creek: D.O. (COGUSM12)
* Gunnison River, Upper Gunnison Segment 4, Taylor River: Pb (COGUUG04)
* Gunnison River, Upper Gunnison Segment 10, Redwell Creek: pH (COGUUG10)
* Gunnison River, Upper Gunnison Segment 15, S. Beaver Creek: Fe(Trec) (COGUUG15)
* Gunnison River, Upper Gunnison Segment 16, Ohio Creek: E. coli (COGUUG16)
* Gunnison River, Upper Gunnison Segment 17, Antelope Creek: E. coli (COGUUG17)
* Gunnison River, Upper Gunnison Segment 23, Stewart Creek: Fe(Trec) (COGUUG23)
* Gunnison River, Upper Gunnison Segment 26, Mesa Creek: Cu (COGUUG26)
* Gunnison River, Upper Gunnison Segment 31, Palmetto Gulch: Ag (COGUUG31)
* Gunnison River, Uncompahgre Segment 2, Uncompahgre River: Pb (COGUUN02)
* Gunnison River, Uncompahgre Segment 3b, Ridgway Reservoir: Pb, Zn (COGUUN03b)
* Gunnison River, Uncompahgre Segment 4c, Uncompahgre River: Pb (COGUUN04c)
* Gunnison River, Uncompahgre Segment 7, Gray Copper Gulch: pH (COGUUN007)
* Gunnison River, Lower Dolores Segment 2, Dolores River: E. coli (COGULD02)
* Gunnison River, Lower Dolores Segment 3a, Disappointment Creek: Se, E. coli (COGULD03a)
* Gunnison River, Lower Dolores Segment 4, West Paradox Creek: E. coli, Fe(Trec) (COGULD04)
* Gunnison River, Lower Dolores Segment 5, Roc Creek: E. coli (COGULD05)
* Lower Colorado, Lower Colorado Segment 4b, South Canyon Hot Springs: Pb (COLCLC04b)
* San Juan/Dolores Rivers, Animas and Florida Segment 3c, Arrastra Gulch: Pb (COSJAF03c)
* San Juan/Dolores Rivers, Animas and Florida Segment 12a, Electra Reservoir: Ag, Zn (COSJAF12a)
* San Juan/Dolores Rivers, Animas and Florida Segment 13a, Junction Creek: Ag, E. coli (COSJAF13a)
* San Juan/Dolores Rivers, Upper Dolores Segment 11, Lost Canyon Creek: E. coli (COSJDO11)
* San Juan/Dolores Rivers, La Plata Segment 3a, Cherry Creek: Cu (COSJLP03a)
* San Juan/Dolores Rivers, La Plata Segment 4a, E. Mancos River: Pb (COSJLP04a)
* San Juan/Dolores Rivers, La Plata Segment 4a, Mancos River: Cu, Pb (COSJLP04a)
* San Juan/Dolores Rivers, La Plata Segment 8a, Tribs to McElmo Creek: E. coli (COSJLP08a)
* San Juan/Dolores Rivers, Piedra Segment 5, Williams Creek Reservoir: pH, Zn, Fe(Trec), D.O. (COSJPI05)
* San Juan/Dolores Rivers, Piedra Segment 8a, Williams Creek: pH, Cu (COSJPI05)
* San Juan/Dolores Rivers, Piedra Segment 6a, Stollsteimer Creek: Fe(Trec), E. coli (COSJPI06a)
* San Juan/Dolores Rivers, San Juan Segment 1, Navajo River: E. coli (COSJSJ01)
* San Juan/Dolores Rivers, San Juan Segment 5, San Juan River: Pb, (COSJSJ05)
* San Juan/Dolores Rivers, San Juan Segment 6a, San Juan River: Pb, Cu (COSJSJ06a)
* San Juan/Dolores Rivers, San Juan Segment 6a, Echo Canyon Reservoir: pH (COSJSJ06a)
* San Juan/Dolores Rivers, San Juan Segment 9a, Rio Blanco: Ag, Pb (COSJSJ09a)
* San Juan/Dolores Rivers, San Juan Segment 10, Rito Blanco: E. coli (COSJSJ10)
* South Platte, Upper South Platte Segment 17a, Rocky Mountain Lake: Cu, DO (COSPUS17a)
* South Platte, Upper South Platte Segment 23, Huston Lake: E. coli (COSPUS23)
* Upper Colorado, Eagle River Segment 9a, Eagle River from Berry Creek to Ute Creek: Temperature (COUCEA09a)
* Upper Colorado, Eagle River Segment 9a, Eagle River from Gore Creek to Berry Creek and from Squaw Creek to Rube Creek: Sediment (COUCEA09a)
* Upper Colorado, Upper Colorado Segment 10c, Fraser River: Pb (COUCUC10c)
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:
* Arkansas, Upper Arkansas Segment 10, Twin Lake West Cu (COARUA10)
* Gunnison, Lower Gunnison Segment 7, Tongue Creek: Se (COGULG07)
* Gunnison, Uncompahgre Segment 9, Sneffels Creek: Zn (COGUUN09)
* Lower Colorado, White River Segment 11, Rio Blanco Reservoir: pH (COLCWH11)
* South Platte, Boulder Creek Segment 9, Boulder Creek: Aquatic Life Use (COSPBO09)
* South Platte, Big Thompson Segment 11, Carter Lake: As (COSPBT11)
* South Platte, Big Thompson Segment 16, Lake Estes: Pb (COSPBT16)
* South Platte, Cache la Poudre Segment 14, Horsetooth Reservoir: Cu, As (COSPCP14)
* South Platte, Lower South Platte Segment 3, Jackson Reservoir: pH (COSPLS03)
* South Platte, Middle South Platte Segment 4, Barr Lake: D.O. (COSPMS04)
* South Platte, Middle South Platte Segment 7, Horse Creek Reservoir: D.O. (COSPMS07)
* South Platte, St. Vrain Segment 3, St. Vrain Creek from Left Hand Creek confluence to confluence with Boulder Creek: Aquatic Life Use (COSPSV03)
* South Platte, Upper South Platte Segment 17a, Rocky Mountain Lake: pH, Cu (COSPUS17a)
* South Platte, Upper South Platte Segment 17a, Ferril Lake, Smith Lake: pH (COSPUS17a)
* South Platte, Upper South Platte Segment 17a, Duck Lake: pH, NH3 (COSPUS17a)
* South Platte, Upper South Platte Segment 23, Aqua Golf, Overland, Parkfield, and Huston Lakes: pH (COSPUS23)
* South Platte, Upper South Platte Segment 23, Vanderbilt Lake: DO (COSPUS23)
In June of 2010, the Commission adopted a two-month averaging period for the existing E. coli criteria. Evaluation of the E. coli standard is over fixed two-month intervals. Where adequate data were available two-month intervals were assessed. Where adequate data were not available data were assessed either seasonally or for the entire period of record.
For lakes and reservoirs, the MWAT is assumed to be equivalent to the maximum WAT. When a lake or reservoir is stratified, the upper portion may exceed the applicable temperature standards in the basin regulations, provided that an adequate refuge exists in water below the upper portion. Adequate refuge depends on concurrent attainment within a given profile of the temperature standard and applicable dissolved oxygen standards. Attainment of the temperature standard below the upper portion is based on comparison with individual depths because of the need to verify concurrent attainment with the DO standard. If the refuge is not adequate because of low dissolved oxygen levels, the lake or reservoir will be listed as impaired for dissolved oxygen rather than for temperature.
Eagle River Segments 6, 8 and 9a:
The Division originally proposed to list the following segments in the Eagle River Basin: the mainstem of Eagle River Segment 9a for sediment, temperature, and Aquatic Life Use impairment, and several tributaries to the Eagle River for impairment of the Aquatic Life Use (Provisional) including Black Gore Creek, Beaver Creek, Lake Creek, Red Sandstone Creek and Gore Creek. Division staff worked with stakeholders in the Eagle River watershed to examine the data and further narrow the issues potentially in dispute. Through this work additional data was made available. Based upon the additional data received and reviewed by Division staff, the Division revised its proposal. In general, parties agreed with the Division's refined proposal for the Aquatic Life Listings in the Eagle River Subbasin. Eagle River stakeholders opposed the Division's proposal to list the mainstem of the Eagle River (Segment COUCEA09a) for temperature. They presented an alternative proposal to M & E list a 6-mile long portion of the segment from Berry Creek to Ute Creek. Evidence presented by the Eagle River Water & Sanitation District showed that the only temperature excursions in this stream reach occurred in the early part of the winter shoulder season and wastewater effluent did not cause the excursions. The District will continue collecting data and will work with the Division to complete additional analysis to determine whether the temperature excursions are a result of anthropogenic activities in the watershed. The Commission adopted the Eagle River Basin stakeholders' proposal.
Upper Colorado River Segment 3 (COUCUC03):
Trout Unlimited referenced a report prepared by the Division of Parks and Wildlife (Nehring 2011) which contained significant site-specific macroinvertebrate and other aquatic life information and analysis for the portion of the Colorado River mainstem between Windy Gap Reservoir and its confluence with the Blue River. The Commission finds that given the fact that there are conflicting MMI scores on this segment, said portion of this segment should be placed on the Monitoring and Evaluation list at this time.
Western Resource Advocates White River Basin:
WRA proposed the addition of White River Segments COLCWH13b, COLCWH13c, COLCWH14a, COLCWH14b, COLCWH15 and COLCWH20 on either the 303(d) or M&E Lists for selenium (COLCWH13b) or total recoverable iron. Following additional data that was submitted by Shell in its Responsive Prehearing Statement, WRA modified its proposal. WRA supported listing a portion of COLCWH13b, Duck Creek, on the 303(d) List for selenium. However, the Commission agreed with the Division that the 2008 Statement of Basis and Purpose language in Regulation #37, Classifications and Numeric Standards for the Lower Colorado River Basin, identifies that the four sites used to create the ambient selenium standard should be assessed in aggregate. The Commission supports the Division's position to include COLCWH13c and a portion of COLCWH14a (the mainstem Piceance Creek from Willow Creek to Hunter Creek) for inclusion on the 303(d) List for total recoverable iron.
Southwestern Water Conservation District E. coli:
The Commission has placed several stream segments (COGULD02, COGULD03a, COGULD04, COGULD05, COSJAF13a, COSJDO11, COSJLP08a, COSJPI06a, COSJSJ10, and COSJSJ03) on the M&E List for E. coli based on data from four or fewer measurements as outlined in the Listing Methodology. Because of the limited number of data points, the listings were based on either a seasonal or annual geometric mean, rather than the two-month averaging period. As a result, the Commission has concluded that the data at these sites indicate potential impairment of the E. coli standard, warranting listing on the M&E List so that additional measurements can be collected.
Lower Colorado Segment 3 (COLCLC03):
Lower Colorado Segment 3 was proposed to be removed from the 303(d) List for selenium impairment due to attainment of standards. USFWS opposed its removal from the list because the segment is critical habitat for the endangered Colorado pikeminnow and razorback sucker. The Commission acknowledges the significance of this issue, but given the fact that the segment is in attainment of its selenium standard, the segment should be removed from the list. If the USFWS feels that the standard is not protective of endangered fish species, the Commission recommends they pursue an alternative standard in the next Colorado basin rulemaking hearing.
Animas River (COSJAF05a):
La Plata Energy Council expressed concern with listing segment COSJAF05a as impaired for manganese. In segment COSJAF05a there is an actual water supply use in the upper portion of the segment. However, there is no actual water supply use in the lower reach below the intake to the Animas-La Plata Project. In 2000, when the Commission adopted the table value criteria for manganese based on secondary water supply standards, the Commission adopted Statement of Basis and Purpose language in Section 31.37 indicating that its action could result in the situation facing La Plata - that is, a segment with a water supply classification but where the only actual water supply use is upstream of point source dischargers. The Commission determined in 2000 that the appropriate course of action is for the Commission to consider resegmentation of that stream. Accordingly the Commission encourages La Plata to pursue resegmentation in the Regulation #34 basin rulemaking hearing if they believe it is warranted.
Marston Forebay (COSPUS22 or COSPBE11):
Marston Forebay was listed as Segment COSPUS22 in the 2010 version of Regulation #93, when in fact, it is correctly included in COSPBE11. Marston Forebay was originally placed on the M&E List in 2010 because dissolved oxygen (DO) concentrations were below the standard in the metalimnion (middle layer of the reservoir). In 2010, the DO standard was revised in Regulation 31. The current DO standard only applies to the top 0.5-2 meters of the water column, unless assessing for refuge with regards to the temperature standard. When assessing against the revised standard, Marston is now attaining the DO standard, as DO readings are above 6 mg/L in the top 2 meters of the water column on all dates. As a result, the Division proposed to remove Marston from the M&E List. The Commission agreed with the Division's recommendation and removed Marston from the M&E List for this reason.
Denver Water also requested a finding that Marston is not "waters of the state". The Commission believes that a Regulation #38 rulemaking hearing is the appropriate forum in which to consider any formal regulatory conclusion regarding this issue.
Ralston Creek (COSPCL17b):
The Division originally placed Ralston Creek on the 303(d) List for impairment of its Water Supply Use-based uranium standard. Cotter Corporation opposed this listing and its high priority listing due to ongoing cleanup work at the Schwartzwalder Mine Site. The Division recognizes that Cotter Corporation is actively addressing non-attainment of the primary drinking water uranium standard in Ralston Creek, and the Division anticipates continued cooperation during development of a Category 4b Plan. However, pending revisions to the standard, the Commission finds that COSPCL17b should be retained on the 303(d) List in the interim with a high priority.
Wildhorse Creek - Segment COARMA04a:
Bill Thiebaut, District Attorney for the Tenth Judicial District, Colorado submitted an alternative proposal to add selenium to the existing listing for E.coli for Wildhorse Creek. After review of the data submitted, the Division agreed with the alternative proposal. Pueblo West opposed this listing as data for the middle portion of the segment attains the ambient based selenium chronic standard of 597 ug/L as well as the ambient based acute standard of 708 ug/L. It has generally not been the practice of the Commission to 303(d) list the majority of a segment except for a portion in the middle. In addition, there was discussion in regards to the appropriateness of the adopted ambient based standard. Pueblo West has expressed interest in reviewing this standard in a future rulemaking hearing. Until revisions to the standard can be made, the Commission has added the entire segment to the 303(d) List for selenium.
Pueblo West raised concerns about whether the current ambient based selenium standard for Middle Arkansas segment 4a is still the appropriate standard. This issue was discussed and it was determined that revising the ambient based standard based on new data is not appropriate for this rulemaking but could be addressed in the next basin hearing for Regulation #32 in June 2013. If the ambient based standard is modified during that proceeding, the appropriateness of the 303(d) listing for this segment would be revisited in the next rulemaking hearing for Regulation #93 in December 2013. The Commission does not expect that the Division would proceed with development of a TMDL between now and the Regulation #32 hearing in June 2013.
PARTIES TO THE RULEMAKING HEARING
