5 Colo. Code Regs. § 1002-33.44
The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; 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:
The Commission decided to split lakes/reservoirs from segments that contain both streams and lakes/reservoirs so that new temperature standards could be adopted. Lakes and reservoirs were deleted from the following segments that previously encompassed both streams and lakes/reservoirs:
Upper Colorado River segments: 1, 2, 9.
Blue River segment: 16.
Roaring Fork River segment: 1.
North Platte River segments: 1, 2, 4a.
Yampa River segments: 1a, 19.
The following are newly created lakes/reservoirs segments:
Upper Colorado River segments: 11, 12.
Blue River segments: 21, 22.
Eagle River segments: 13, 14.
Roaring Fork River segments: 11, 12.
North Platte River segments: 8, 9.
Yampa River segment: 1b.
Some renumbering and/or creation of new segments was made due to information which showed that:
Upper Colorado River 1: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 11.
Upper Colorado River 2: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 12 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 12.
Upper Colorado River 6a: The segment description was amended to reflect the split of Segment 10 into Segments 10a-c; the additional exclusion of specific listings in Segments 1, 2, 4, 5 and 9; as well as the decision to move the endpoint of the segment from below to above the confluence of Muddy Creek and the Blue River. This alteration eliminated confusion regarding the segment associations pertinent to Muddy Creek and its tributaries. Muddy Creek and its tributaries are intended to be included in portions of segment 7a, 7b, and 7c. The alteration of this segment was necessary to facilitate the adoption of appropriate temperature standards.
Upper Colorado River 7a: The segment description was amended to exclude listings in Segment 7c and clarify the upper boundary of the segment as a point immediately above both the Blue River and Muddy Creek. The alteration of this segment, and the creation of Segment 7c were necessary to facilitate the adoption of appropriate temperature standards (CS-II).
Upper Colorado River 7b: The segment description was amended to include all wetlands within the existing segment.
Upper Colorado River 7c: This new segment was created to group similar streams formerly found within segment 7a. Muddy Creek from the source to a point immediately below the confluence with Eastern Gulch; all tributaries to and wetlands of Muddy Creek from the source to the outlet of Wolford Mountain Reservoir, except for listings in Segment 4. The mainstems of Derby, Blacktail, Cabin and Red Dirt Creeks (all below Wolford Mountain Reservoir), including all tributaries and wetlands, from their sources to their confluence with the Colorado River; except for specific listings in segment 4, were included in the newly created segment. The creation of this segment, and the resultant alteration of Segment 7a were based on geographic location and was necessary to facilitate the adoption of appropriate temperature standards (CS-I).
Upper Colorado River 9: The segment description was amended to exclude lakes and reservoirs and to include streams within the Vasquez Wilderness Area. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 11.
Upper Colorado River 10a: The segment description was amended to reflect a new endpoint of the mainstem portion of the segment. The mainstem portion of the segment now ends at a point immediately below the Rendezvous Bridge, while all tributaries to the Fraser, including wetlands, from the source to the confluence with the Colorado River are still found within this segment. The split of the mainstem, and the resultant creation of Segments 10b and 10c were necessary to facilitate the adoption of temperature standards. (See Section P)
Upper Colorado River 10b: This new segment was created for the mainstem of the Fraser River from a point immediately below the Rendezvous Bridge to a point immediately below the Hammond Ditch. The creation of this segment, and the alteration of Segment 10a were necessary to facilitate the adoption of temperature standards. This portion of the mainstem was previously part of Segment 10. (See Section P)
Upper Colorado River 10c: This new segment was created for the mainstem of the Fraser River from a point immediately below the Hammond Ditch to the confluence with the Colorado River. The creation of this segment, and the alteration of Segment 10a and 10b were necessary to facilitate the adoption of temperature standards. This portion of the mainstem was previously part of Segment 10. (See Section P)
Upper Colorado River 11: This new segment was created for lakes located in Rocky Mountain National Park as well as all Wilderness areas within the Upper Colorado River Basin. The creation of this segment, and the alteration of Segments 1 and 9 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segments 1 and 9.
Upper Colorado River 12: This new segment was created for lakes located in Arapahoe National Recreation Area. The creation of this segment, and the alteration of Segment 2 were necessary to facilitate the adoption of appropriate temperature standards. These lakes, including Grand Lake, Shadow Mountain Lake, and Lake Granby were previously part of Segment 2.
Blue River 3: The segment description was amended to include only lakes located in the Blue River Drainage above Dillon Reservoir with the exception of lakes located within Segment 21. The alteration of this segment, and the resultant creation of Segment 4 were necessary to facilitate the adoption of appropriate temperature standards. Stream portions of the segment were moved to Segment 4.
Blue River 4a: This new segment was created for tributaries to Dillon Reservoir, including wetlands, except for specific listings in Segments 1, 2a, 2b, 4b, 5, 6, and 10-14. The creation of this segment, and the alteration of Segment 3 were necessary to facilitate the adoption of appropriate temperature standards and antidegradation designations. These streams were previously part of Segment 3. (See Section R)
Blue River 4b: This new segment was created for the North Fork of the Swan River, including all tributaries and wetlands, from the source to the confluence with the Swan River. The creation of this segment, and the alteration of Segment 4a, were necessary to facilitate the adoption of an outstanding waters antidegradation designation. (See Section R)
Blue River 6a: The segment description was amended to reflect the creation of segment 6b. A portion of this segment; Jones gulch, including all tributaries and wetlands; was also moved to Segment 8. The alteration of this segment, the creation of Segment 6b, and the inclusion of Jones Gulch (and tributaries and wetlands) in Segment 8 were necessary to facilitate the adoption of appropriate zinc standards.
Blue River 6b: This new segment was created for the mainstem of Camp Creek, including all tributaries and wetlands from the source to confluence with the Snake River. The creation of this segment and the alteration of Segment 6a were necessary to facilitate the adoption of appropriate zinc standards.
Blue River 8: The segment description was amended to reflect the inclusion of the mainstem of Jones gulch, including all tributaries and wetlands from the source to the confluence with the Snake River. The addition of these stream reaches, formerly found in segment 6, was necessary to facilitate the adoption of appropriate zinc standards.
Blue River 16: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 21 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 21.
Blue River 21: This new segment was created for lakes located in Wilderness areas within the Blue River Basin. The creation of this segment, and the alteration of Segments 3 and 16 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 16.
Blue River 22: This new segment was created for lakes located in the Blue River drainage below Dillon Reservoir, except specific listings in Segment 21. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment.
Eagle River 9a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at a point immediately below the confluence with Rube Creek. The split of the segment, and the resultant creation of Segment 9b were necessary to facilitate the adoption of appropriate temperature standards.
Eagle River 9b: This new segment was created for the mainstem of the Eagle River below the confluence with Rube Creek. The creation of this segment, and the alteration of Segment 9a were necessary to facilitate the adoption of appropriate temperature standards. This portion of the mainstem was previously part of Segment 9.
Eagle River 10a: The segment description was amended to exclude specific listings in segment 10b. The alteration of this segment and the creation of Segment 10b were necessary to facilitate the adoption of appropriate antidegradation designations. (See Section R)
Eagle River 10b: This new segment was created for Abrams Creek, including all tributaries and wetlands, from the source to the eastern boundary of the United States Bureau of Land Management lands. The creation of this segment, and the alteration of Segment 10a, were necessary to facilitate the adoption of an outstanding waters antidegradation designation. (See Section R)
Eagle River 13: This new segment was created for lakes located in Wilderness areas within the Eagle River Basin. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment.
Eagle River 14: This new segment was created for lakes located in the Eagle River Basin, except for specific listings in Segment 13. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment.
Roaring Fork River 1: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 11.
Roaring Fork River 3a: The segment description was amended to reflect a new endpoint of the mainstem portion of the segment. The mainstem portion of the segment now ends at a point immediately below the confluence with the Fryingpan River. All tributaries to the Roaring Fork, including wetlands, from the source to the confluence with the Colorado River are still found within this segment, except for specific listings in Segment 1 and 3b-10. The split of the mainstem, and the resultant creation of Segment 3c were necessary to facilitate the adoption of appropriate temperature standards.
Roaring Fork River 3c: This new segment was created for the mainstem of the Roaring Fork below the confluence with the Fryingpan River to facilitate the adoption of appropriate temperature standards. The mainstem of Three Mile Creek, including all tributaries and wetlands, from the source to the confluence with the Roaring Fork River, is also included in this segment. The creation of this segment, and the alteration of Segment 3a were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 3a.
Roaring Fork River 11: This new segment was created for lakes located in Wilderness areas within the Roaring Fork River Basin. The creation of this segment, and the alteration of Segment 1 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 1.
Roaring Fork River 12: This new segment was created for lakes located in the Roaring Fork River Basin, except specific listings in Segment 11. The creation of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously unassigned to a particular segment.
North Platte River 1: The segment description was amended to also exclude lakes and reservoirs and to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 8.
North Platte River 2: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment, and the resultant creation of Segment 9 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 9.
North Platte River 4a: The segment description was amended to exclude lakes and reservoirs. The segment description was additionally amended to exclude listings in segment 4b. The alterations of this segment, and the resultant creations of Segments 4b and 9 were necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 9.
North Platte River 4b: This new segment was created to group similar streams formerly found within segment 4a. Included in this segment is the Illinois River and all tributaries and wetlands from a point immediately below the confluence with Indian Creek to the confluence with the Michigan River, except for specific listings in Segments 7a and 7b. The mainstem of the Canadian River below 12E Road to the confluence with the North Platte River, as well as all tributaries and wetlands which enter the Canadian River from the southwest side of the mainstem, were also included in the new segment.
North Platte River 5a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at a point immediately below the confluence with the North Fork Michigan River. The alteration of this segment, and the resultant change of Segment 5b were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 5b: The segment description was amended to reflect a new upper boundary of the segment. The segment now starts at a point immediately below the confluence with the North Fork Michigan River. The alteration of this segment, and the change of Segment 5a were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 7a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at the outlet of Spring Creek (Number 31) Reservoir. The alteration of this segment, and the resultant creation of Segment 7b were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 7b: The segment description was amended to reflect a new upper boundary of the segment. The segment now starts at the outlet of Spring Creek (Number 31) Reservoir. The creation of this segment, and the alteration of Segment 7a were necessary to facilitate the adoption of appropriate temperature standards.
North Platte River 8: This new segment was created for lakes located in Wilderness areas within the North Platte River Basin. The creation of this segment, and the alteration of Segment 1 were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 1.
North Platte River 9: This new segment was created for lakes located in the North Platte River Basin, except specific listings in Segments 8. The creation of this segment, and the alteration of Segments 2 and 4a were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segments 2 and 4a.
Yampa River 1a: The segment description was amended to also exclude lakes and reservoirs and to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 1b.
Yampa River 1b: This new segment was created for lakes located in Wilderness areas within the Yampa River Basin. The creation of this segment, and the alteration of Segment 1a were necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 1a.
Yampa River 2a: The segment description was amended to reflect a new endpoint of the segment. The segment now ends at a point immediately below the confluence with Oak Creek. The alteration of this segment, and the resultant creation of Segment 2c were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 2b: The segment description was amended to include all lakes and reservoirs tributary to the Little Snake River and to reflect the split of Segment 1 into Segments 1a and 1b. The segment description was additionally amended to reflect the creation of Segment 1b. The alteration of this segment was necessary to facilitate the adoption of appropriate temperature standards. These lakes were previously part of Segment 19.
Yampa River 2c: This new segment was created for the mainstem of the Yampa River below the confluence with Oak Creek. The creation of this segment, and the alteration of Segment 2a were necessary to facilitate the adoption of appropriate temperature standards. This portion of the mainstem was previously part of Segment 2a.
Yampa River 3: The segment description was amended to exclude the new Segment 13f. The alteration of this segment, and the creation of Segment 13f were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 11: This new segment was created for Fish Creek, including all tributaries and wetlands, above Country Road 27, except for specific listings in Segment 20. The creation of this segment, and the alteration of Segment 12 were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 12.
Yampa River 12: The segment description was amended to reflect the creation of Segment 11 which removed the Fish Creek, including all tributaries and wetlands, above County Road 27 from the segment. The alteration of this segment, and the resultant creation of Segment 11 were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 13a: The segment description was amended to reflect the creation of Segment 13f, which removed the portion of Trout Creek, including all tributaries and wetlands, below the confluence with Fish Creek from the segment. The alteration of this segment, and the resultant creation of Segment 13f were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 13d: The segment description was amended to clarify which Dry Creek is intended to be described for this segment. This segment is meant to describe the Dry Creek that has its confluence with the Colorado River immediately below the town of Hayden, Colorado.
Yampa River 13f: This new segment was created for Trout Creek, including all tributaries and wetlands, below the confluence with Fish Creek. The creation of this segment, and the alteration of Segment 13a were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 13a.
Yampa River 14: The segment description was amended to reflect new endpoints of the segment. The segment now ends at points immediately below the confluence with Calf Creek and below 80A Road on the Dry Fork of Elkhead Creek. The alteration of this segment, and the resultant creation of Segment 15 were necessary to facilitate the adoption of appropriate temperature standards.
Yampa River 15: This new segment was created for Elkhead Creek, including all tributaries and wetlands, from a point immediately below the confluence with Calf Creek and below 80A Road on the Dry Fork of Elkhead Creek, to the confluence with the Yampa River. The creation of this segment, and the alteration of Segment 14 were necessary to facilitate the adoption of appropriate temperature standards. These streams were previously part of Segment 14.
Yampa River 19: The segment description was amended to exclude lakes and reservoirs. The alteration of this segment was necessary to facilitate the adoption of appropriate temperature standards. Lakes and reservoirs found in this segment are now part of Segment 2b.
Yampa River 20a: The segment description was amended to reflect new endpoints of the segment. The Elkhead Creek and First Creek portions of the segment now end at the eastern boundary of state lands in California Park. The alteration of this segment, and the resultant creation of Segment 20b were necessary to facilitate the adoption of the appropriate recreation use classification. (See Section X)
Yampa River 20b: This new segment was created for portions of First Creek and Elkhead Creek below the eastern boundary of state lands in California Park. The creation of this segment, and the alteration of Segment 20a were necessary to facilitate the adoption of the appropriate recreation use classification. These streams were formerly part of Segment 20. (See Section X)
The Commission reviewed information regarding existing aquatic communities. The following changes to the existing aquatic-life use classifications were made.
Yampa River 14 was split and portions were moved to segment 15: a change from Cold 1 to Warm 1.
As part of the Basic Standards hearing of 2005, recreation classifications were revised into four new classifications. The Commission reviewed the previous segment classifications (1a, 1b and 2) and determined the appropriate new classification based on classification criteria presented as part of the Basic Standards Hearing, use attainability analyses or other basis. In addition, during the 2005 Basic Standards Hearing, the transition from the use of the fecal coliform standard to E. coli standard was completed. Fecal coliform criteria were deleted from the numeric standards.
Based on the information that showed existing primary contact recreation use is in place in at least a portion of the segment, the Commission converted the following segments from Recreation Class 1a to Recreation Class E with a 126/100 ml E. coli standard:
Upper Colorado River segments: 1-5, 7b, 8-10a.
Blue River segments: 1-3, 5, 6, 8-10, 14-18.
Eagle River segments: 1-9a, 10, 12.
Roaring Fork River segments: 1-3a, 4-10.
North Platte River segments: 1, 3, 4a, 5a.
Yampa River segments: 1a, 2a, 2b, 3, 6, 8, 13a-d, 14, 18-20a.
The following segments were converted from Recreation Class 1b to Recreation Class P with a 205/100 ml E. coli standard:
Blue River segments: 11-13.
Eagle River segment: 11. North Platte River segment: 2.
Yampa River segments: 5, 7.
Based on review of existing Use Attainability Analyses showing that primary contact recreation is not attainable, the following segments were converted from Recreation Class 2 to Recreation Class N classification with 630/100 ml E. coli standard:
Upper Colorado River segments: 6b, 6c, 7a.
Blue River segments: 7, 19, 20.
Roaring Fork River segment: 3b.
North Platte River segments: 5b-7a.
Yampa River segments: 4, 12, 13e.
Based on review of information regarding the location of public water supplies, no additional Water Supply use classifications or standards were added to Regulation No. 33.
A review of the standards associated with the Agriculture use classification showed that many segments were missing a nitrate standard protective of the use. A nitrate standard, NO3 =100, was added to the following segments with Agriculture use classification:
Upper Colorado River segments: 6b, 6c.
Blue River segments: 11, 13.
Roaring Fork River segment: 4.
Yampa River segments: 5, 7, 13b-e.
Decoupling Cold 2 and UP: As part of the Basic Standards hearing of 2005, the Commission eliminated the direct linkage between cold-water aquatic life class 2 and the use-protected designation. Therefore, all cold-water aquatic life class 2 segments that are use-protected were reviewed to determine if that designation is still warranted. The following segments are now reviewable:
Upper Colorado River segments: 6b, 6c.
Blue River segment: 12.
Eagle River segment: 11.
Roaring Fork River segments: 3b.
North Platte River segment: 7a.
Yampa River segments: 4, 12.
Decoupling Aquatic Life Warm 2 and UP: There was no decoupling of the segments with an Aquatic Life Warm 2 classification in the Basin.
Outstanding Waters: See Section R.
There is one segment in the Basin that has ambient metals standards. Ambient standards are adopted where natural or irreversible man-induced conditions result in exceedances of table value standards. The Commission reviewed the information that is the basis for these standards as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped. The following ambient based standards have been revised based on a recalculation using existing data:
Yampa River segment 13b: Middle Creek: Fe(ch)=1035(Trec).
The WAT standard is not attainable in the majority of large lakes (>100 acres in surface area) including many lakes with apparently healthy cold-water fish populations. Summertime temperature for large lakes and reservoirs (collectively referred to as lakes) is very well correlated to the lake's elevation. Since the thermal properties are natural or man-induced irreversible (in the case of reservoirs) the Commission adopted ambient temperature standards for large lakes wherever data were available to characterize a WAT. For lakes, the WAT is assumed to be equivalent to the average temperature of the mixed layer. If there were less than three years of data, the highest observed WAT was selected for the summertime ambient standard. If three to five years of data were available, the second highest observed WAT was used as the ambient standard. Where temperature data from multiple stations in the same reservoir were collected on the same date, the Division used an average of those stations to calculate the WAT.
Upper Colorado River segment 5: | Wolford Mountain Res: | April-December T(WAT) | = 19.73°C |
. | . | (See Section O.) | |
. | Williams Fork Res: | April-December T(WAT) | = 21.55°C |
Upper Colorado River segment 12: | Shadow Mountain Res: | April-December T(WAT) | = 19.30°C |
. | Granby Reservoir: | April-December T(WAT | )= 19.42°C |
Roaring Fork River segment 12: | Ruedi Reservoir: | April-December T(WAT) | = 20.33°C |
North Platte River segment 9: | Lake John: | April-December T(WAT) | = 20.77°C |
. | North Delaney Lake: | April-December T(WAT) | = 20.14°C |
Yampa River segment 2b: | Stagecoach Reservoir: | April-December T(WAT) | = 21.40°C |
. | Steamboat Reservoir: | April-December T(WAT) | = 21.60°C |
New Table Value Standards: 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 33.6(3) were modified to conform to Regulation No. 31.
Site-Specific Zinc Standards for Mottled Sculpin: In low hardness situations (hardness below 113 mg/L) the new zinc chronic equation is not protective of mottled sculpin (Cottus bairdi), a native west-slope fish species. The Commission adopted a mottled sculpin-specific chronic zinc equation as site-specific standards for the following segments that are inhabited by mottled sculpin and also have low hardness:
Upper Colorado River segments: 1-3, 7b, 8, 10a-c.
Blue River segments: 1, 4a, 4b, 8, 14, 17.
Eagle River segments: 1, 2, 4, 6, 7a, 8.
Roaring Fork River segments: 2, 5, 6, 10.
Yampa River segments: 2a, 2c, 3, 8, 13a, 18, 19.
Chromium III Standards: A review of the chromium III standards showed that the chromium standard associated with the Water Supply use classification was not protective of aquatic life where the average hardness was less than 61 mg/l. A chromium standard, CrIII(ch)=TVS was added to following segments with average hardness values less than 61 mg/l.
Upper Colorado River segments: 1, 2, 8, 10a-c.
Blue River segments: 4a, 4b, 5, 8 - 10, 15, 18.
Eagle River segments: 1, 4, 6, 7a, 7b.
Roaring Fork River segments: 2, 5.
North Platte River segments: 1, 2, 4b.
Yampa River segments: 1a, 3, 8, 18.
For arsenic, each use (except recreation) has a different arsenic ("As") value, including Fish Ingestion (FI) and Water Plus Fish (W+F). In different combinations of uses, different values become the most limiting. In order to eliminate the confusion, the Commission added the operative value to the individual segments. The following matrix displays the most limiting arsenic criteria.
Most Limiting Arsenic Criteria Depending on the Possible Combinations of Uses and Qualifiers
If the Use Classifications were: | These Arsenic Standards were Applied (dissolved unless otherwise noted) |
Class 1 aquatic life, water supply | As(ac) = 340, As(ch) = 0.02(Trec) |
Class 2 aquatic life (water + fish standards), water supply | As(ac) = 340, As(ch) = 0.02(Trec) |
Class 2 aquatic life (no fish ingestion standards), water supply | As(ac) = 340, As(ch) = 0.02 - 10(Trec) |
Class 1 aquatic life | As(ac) = 340, As(ch) = 7.6(Trec) |
Class 2 aquatic life (fish ingestion standards) | As(ac) = 340, As(ch) = 7.6(Trec) |
Class 2 aquatic life (no fish ingestion standards), agriculture | As(ac) = 340, As(ch) = 100(Trec) |
Agriculture only | As(ch) = 100(Trec) |
Water supply only | As(ch) = 0.02 - 10(Trec) |
At the 2005 Basic Standards rulemaking hearing, the Commission changed the drinking water supply table value for uranium from 40 pCi/L to 30 ug/L.
All temporary modifications were re-examined to determine whether to delete the temporary modification or to extend them, either as existing or with modifications of the numeric standards. Because of the June 2005 changes to Regulation No. 31, temporary modifications were not automatically extended if non-attainment persisted. The following segments had temporary modifications that were not renewed:
Blue River segments: 6, 7, 12.
The following segments have temporary modifications for ammonia that were amended to clarify the chronic standard as 0.02, rather than just "TVS old". As specified in 61.8(2)(c)(iii) (the Permit Rules, Regulation No. 61), where a temporary modification has been adopted, limits in permits are to be set based on the temporary modification and the provision strictly limiting the loading from the facility does not apply. These temporary modifications will be subject to review and rulemaking for the two years before their scheduled expiration in order to track progress towards the full attainment of water body standards and uses.
Yampa River segment: 13d.
In some cases the Commission adopted temporary modifications of underlying standards with the notation of "existing quality" rather than a numeric. This was done where it was not possible to derive an appropriate characterization of current instream concentrations or temperature conditions. The Commission's intent of using the notation "existing quality" is to preserve the status quo during the term of the temporary modification. Dischargers to those segments shall maintain the existing water quality or pollutant loading characteristics of their effluent with respect to the parameter that has the temporary modification. The Commission does not intend the temporary modifications to apply to new facilities or in Preliminary Effluent Limitations. The Commission adopted type iii temporary modifications of temperature standards equal to "existing quality," for the following segments:
Eagle River segments: 8 and 9a.
As part of the Basic Standards hearing of 2007, new table values were adopted for temperature. Temperature standards were applied to individual segments based upon the distribution of fish species, as provided by the CDOW, temperature data, and other available evidence.
The following segments are cold stream tier one (CS-I):
Upper Colorado River segments: 1, 2, 4, 6a, 7b-10a.
Blue River segments: 1-2b, 4a-20.
Eagle River segments: 1-9a, 10a-12.
Roaring Fork River segments: 1-3a, 4-10.
North Platte River segments: 1, 2, 4a, 5a, 6, 7a.
Yampa River segments: 1a, 2a, 3, 5, 6, 8, 11, 13a,18-20b.
The following segments are cold stream tier two (CS-II):
Upper Colorado River segments: 3, 6b-c, 7a, 10b-c.
Eagle River segment: 9b.
Roaring Fork River segments: 3b, 3c.
North Platte River segments: 3, 4b, 5b, 7b.
Yampa River segments: 2c, 4, 7, 12, 13b-c, 13f, 14.
The following segments are cold lakes or cold large lakes (CL,CLL):
Upper Colorado River segments: 5, 11, 12.
Blue River segments: 3, 21, 22.
Eagle River segments: 13, 14.
Roaring Fork River segments: 11, 12.
North Platte River segments: 8, 9.
Yampa River segments: 1b, 2b.
The following segments are warm stream tier two (WS-II):
Yampa River segments: 13d, 13e, and 15.
The Commission recognizes that in some cases there is uncertainty about the temperature standards adopted in this hearing. The uncertainty stems from a lack of data about temperature or the aquatic community or where there is a conflict between the lines of evidence. It is the Commission's intent that the Division and interested parties work to resolve the uncertainty for the following segments by the next basin-wide review.
Upper Colorado River segment 10b and 10c: limited temperature data indicate that numeric attainment may be a problem but that brook and rainbow trout are present. (See Section P.)
Yampa River segment 13d and 13e: limited temperature data indicate that numeric attainment may be a problem and limited biological information was available. (See Section V.)
Upper Colorado River 6b: The cyanide standard was revised to reflect that CN=0.2 is an acute standard. The standard now reads CN(ac)=0.2.
Upper Colorado River 6a: The recreation use classification was changed from Class 2 (Secondary Contact) to Class P (Potential Primary Contact) to reflect the operation of a guest ranch located on Willow Creek which features fishing and other access to the stream. There are also many other potential opportunities for public access to various stream reaches within this segment.
Upper Colorado River 9: The segment description was amended to include the Vasquez Wilderness Area, which had been previously unlisted within the Upper Colorado River Basin.
Eagle River 7a: The CrIII standard was revised to reflect that the 50(Trec) standard is acute rather than chronic.
North Platte 5b: The CrIII acute standard was revised to reflect that the acute standard is 50(Trec) rather than TVS.
North Platte River 7a/b: The "Water + Fish organics apply" qualifier was changed to "Fish Ingestion" to reflect an oversight from the 2003 hearing and the lack of a water supply use classifications for these segments.
Yampa River 13a: The temporary modification for NH3 found on this segment was moved to Segment 13d. The Hayden treatment plant discharges to Segment 13d, thus prior assignment of this temporary modification to Segment 13a was incorrect.
The Commission corrected several typographical and spelling errors, and clarified segment descriptions.
The River District proposed site-specific D.O. and temperature standards for Wolford Mountain Reservoir. After discussions with the Division, EPA and the Division of Wildlife ("DOW"), the River District agreed to withdraw its proposal in order to further study the possible reasons for non-attainment of the D.O. standard in the reservoir. The Division, EPA, and DOW will assist the River District in developing a study to better understand the reasons for the non-attainment and provide assistance in their respective areas of expertise.
The River District and the Division determined that the WAT for Wolford Mountain Reservoir is 19.73°C based on data collected between 2003 and 2007 and measured at the dam (USGS Station #09041395). When determining compliance with the temperature standard for Wolford Mountain Reservoir in the future, the temperature shall be measured at the dam.
Grand County Water and Sanitation District #1, the Winter Park West Water and Sanitation District, the Fraser Sanitation District, the Winter Park Sanitation District (Grand County Districts) proposed resegmentation and temperature standards for waters in the Fraser River watershed.
The Commission determined that the physical conditions in the Fraser River basin warranted resegmentation based on the instream temperatures, habitat, and fish community composition. Based on instream temperature and fish population monitoring conducted by and for the Grand County Districts and the Grand County Water Information Network (GCWIN), the Commission concluded that a single segment and accompanying temperature standards is not appropriate for the Fraser River. The temperature data indicate a transition from very cold-to cold-to cool in a downstream direction, which is reflected in changes in the fish community with brook trout expected to occur in the upper reaches and a mixed cold water fishery of both game and non-game species in the lower reaches.
Based on these findings, the Commission determined that segment 10 would be split into three distinct segments at specific landmarks and hydrologic breaks that represent shifts in floodplain and stream characteristics. Segment 10a ends at the Rendezvous Bridge, located at or near the former confluence of Leland Creek and the Fraser River. It was determined that CS-I TVS for temperature were appropriate for this upper segment for protection of brook trout.
The rest of pre-existing segment 10 was split into two segments (10b and 10c) at the Hammond ditch, a major irrigation ditch located just north of County Road 8. Even though the classifications and standards are the same for both segments, the stream's physical and biological characteristics are substantially different. CS-II TVS for temperature were applied to both segments 10b and 10c reflecting the presence of rainbow and brown trout; however, the existing temperature data demonstrate a small number of exceedances of the CS-II TVS in segment 10b and numerous exceedances of the CS-II TVS in segment 10c, causing uncertainty regarding attainment of the CS-II TVS in these segments. The data also indicate no significant effect of discharges of municipal effluent on stream temperatures.
The Commission intends to revisit the temperature standards for segments 10b and 10c in 2013. It is anticipated that the ongoing biological and temperature monitoring will provide information to lessen the uncertainties regarding the appropriate long-term stream classifications and temperature standards. (See Section L)
The Northwest Colorado Council of Governments, supported by Grand County and the Greater Grand Lake Shoreline Association, proposed a clarity standard for Grand Lake of 4 meter Secchi disk depth, effective July through September.
The Commission determined that it is appropriate to adopt water quality standards for the protection of Grand Lake's clarity because of Grand Lake's uniqueness as Colorado's largest natural lake. Grand Lake adjoins and complements Rocky Mountain National Park in the headwaters of the Colorado River and its social and economic importance is worthy of protection. Senate Document 80 (which recorded the legislative intent of the federal Congress in February 1937) provided in part that the Colorado Big-Thompson Project must be operated in a manner to preserve the scenic attraction of Grand Lake. Concern about the visible loss of transparency of Grand Lake has resulted in local, state and federal initiatives to address the changes in water quality. The earliest measurement of Grand Lake clarity is 9.2 meters (September 6, 1941). The 85th percentile of clarity measurements from 2006 is 2.7 meters.
The Commission recognizes that this is the first time that a clarity standard has been adopted in the Colorado. Clarity standards are being adopted pursuant to the Basic Standards at section 31.13 , which states "In special cases where protection of beneficial uses requires standards not provided by the classification above, special standards may be assigned after full public notice and hearings." Improvement of clarity within Grand Lake is expected to improve the quality of recreational uses of this unique resource.
The Commission is adopting two clarity standards for Grand Lake. First, the Commission is establishing a narrative clarity standard, to take effect with the other revisions to this regulation. This standard is "the highest level of clarity attainable, consistent with the exercise of established water rights and the protection of aquatic life". This standard is based on the Commission's conclusion that improvement in the clarity of Grand Lake is necessary, while noting that efforts to improve clarity need to be undertaken in a manner consistent with established water rights and need to also consider the protection of the aquatic life use. In basing the standard on "attainability", the Commission intends that attainability is to be judged by whether or not a clarity level can be attained in approximately twenty years by any recognized control techniques that are environmentally, economically, and socially acceptable.
An underlying assumption in setting this narrative standard is that clarity in Grand Lake needs to improve. However, the Commission is not determining in this hearing whether the current evidence of reduced clarity warrants inclusion of Grand Lake on Colorado's Section 303(d) List or the Monitoring and Evaluation List. That issue can be addressed as appropriate in the 2010 hearing on Regulations #93 and #94, based on additional evidence and analysis developed prior to that time.
Second, the Commission is establishing a numerical clarity standard of 4 meter Secchi depth for the months of July through September, with an effective date of January 1, 2014. The intention is that for the majority of the summertime days, the water of Grand Lake shall be clearer than 4 meter Secchi depth. Attainment of the 4 meter Secchi depth standard will be assessed by comparing the 85th percentile of available Secchi depth data collected during the months July through September to the 4 meter standard. Fifteen percent of the measurements may have Secchi depth shallower than 4 meters. When two samples are collected in different locations, or by different agencies on the same day, the Secchi depth value is the average of those samples.
The Commission has determined that the adoption of the 4 meter numerical standard with a delayed effective date is an appropriate policy choice to encourage cooperative efforts to improve Grand Lake clarity prior to the time that a specific numerical standard goes into effect, while assuring that a protective numerical standard will go into effect in 2014 if monitoring, assessment and water quality improvement efforts between now and then have not resulted in identification of a more appropriate numerical standard.
All parties agreed that improvement in Grand Lake water clarity is desirable. The Commission strongly encourages all interested stakeholders to work together to further identify the causes of reduced clarity and to explore options for identifying and implementing reasonable and effective measures to improve clarity, consistent with the other factors noted in the narrative standard. The Commission anticipates that these efforts may result in a proposal for a revised site-specific numerical clarity standard for Grand Lake at a later date.
Concerns have been raised regarding the potential impact of the proposed clarity standard on the exercise of water rights. The Commission recognizes that Section 25-8-104, C.R.S. states in part that "Nothing in this article [the Colorado Water Quality Control Act] shall be construed, enforced or applied so as to cause or result in material injury to water rights." If non-attainment of the numerical clarity standard is determined to be caused by the valid exercise of those water rights and the exceedance cannot be eliminated in a manner consistent with C.R.S. 25-8-104, the Commission would consider adoption of a revised site-specific standard as provided in section 31.7 . The Commission is hopeful that options can be identified to improve Grand Lake clarity in a manner consistent with section 25-8-104. The Commission is not determining in this hearing precisely what types of options and alternatives are or are not consistent with section 25-8-104. The Commission believes that that issue is better addressed in the course of a process that more fully examines the causes of current clarity limitations on Grand Lake and the options for mitigating identified impacts.
While stating that it did not oppose a 4 meter clarity standard for Grand Lake, the Colorado Division of Wildlife noted that it is important that efforts to improve clarity in Grand Lake consider potential effects on recreational fisheries. The Commission intends that potential positive or negative impacts on aquatic life in Grand Lake be taken into account in implementing the narrative standard now being adopted, and in any efforts to consider potential refinement of the numerical standard now being adopted with a delayed effective date.
The Commission believes that this is an appropriate first step toward protecting Colorado's high quality water resources in a manner consistent with law and regulation. As with all standards, the clarity standards for Grand Lake are subject to periodic review, and the Commission expects to revisit this issue in future review cycles.
Based on evidence that shows that water quality meets the requirements of 31.8(2)a and the presence of Colorado River cutthroat trout, the Outstanding Water (OW) designation was added to the new Eagle River segment 10b: Abrams Creek, including all tributaries and wetlands, from the source to the eastern boundary of the United States Bureau of Land Management lands and the new Blue River Segment 4b: North Fork of the Swan River, including all tributaries and wetlands, from the source to the confluence with the Swan River. The Commission understands that existing land uses are in place in these watersheds. The evidence demonstrates that these existing land uses are compatible with the OW designation since the current high level of water quality has been attained with these uses in place. It is the Commission's intent that this OW designation should not be used to establish additional permit requirements for existing uses within this area.
Keystone Resort (Keystone) proposed resegmentation of waters in the Snake River watershed and site-specific standards for Camp Creek and its tributaries.
Blue River segment 6: The Commission moved Jones Gulch from segment 6 to segment 8 based upon monitoring data collected by Keystone which showed that Jones Gulch meets table value standards for metals. The Commission adopted re-segmentation of segment 6 by renumbering segment 6 as segment 6a and establishing segment 6b based on recognized differences in water quality characteristics between the Snake River and the Camp Creek watershed which is located within the Keystone Ski Area. Segment 6b is now the mainstem of Camp Creek, including all tributaries and wetlands from the source to the confluence with the Snake River.
Site-specific standards for dissolved zinc were adopted for Camp Creek based upon the use of the recalculation procedure. Despite the habitat limitations in Camp Creek, and the fact that it currently does not support a fish population, under a modified recalculation approach the recalculation included species expected to occur in the Blue River Basin, including sensitive fish species such as mottled sculpin. The four most sensitive genera used to calculate the site-specific standards included Cottus, Oncorhynchus, Salmo, and Ranatra. The recalculated hardness-based equations are as follows:
zinc (acute) = 0.978*e0.8537 (ln Hardness)+1.5227
zinc (chronic) = 0.986*e0.8537 (ln Hardness)+1.3519
The recalculated standards for zinc are intended to be fully protective of the aquatic life use in Camp Creek. Keystone will implement drainage and snowmaking system improvements including plumbing modifications and changes in management practices to further reduce the amount of water transferred from the snowmaking system to Camp Creek. Keystone is also working with the NWCCOG and other interested stakeholders on the investigation and potential implementation of measures to reduce acid mine drainage impacts from the Peru Creek tributary of the Snake River which will reduce metals concentrations in the snowmaking water supply. If, after these measures have been implemented, it is determined that the recalculated standards are not attainable or if significant additional water quality improvement has been achieved, the Commission will revisit the appropriate standards for Camp Creek.
Blue River segment 8: Monitoring results for water samples collected from 2003 through 2007 show that Jones Gulch meets table value standards. The Commission therefore moved Jones Gulch from Segment 6 to Segment 8.
The Hazardous Materials and Waste Management Division and USEPA Superfund Program (Superfund Proponents) proposed site-specific zinc, copper and cadmium standards for segments on the Eagle River within the Eagle Mine Superfund Site. Similarly, CBS Operations Inc (CBS) (formerly Viacom International Inc) proposed a different set of site-specific zinc, copper and cadmium standards for segments on the Eagle River within the Eagle Mine Superfund Site.
After review of the evidence submitted, the Commission adopted the Superfund Proponents' modified proposal for site-specific standards for the Eagle River Segments 5a, 5b, 5c and 7b as described below. These segments are impacted by historical mining activities at the Eagle Mine Superfund Site.
Zinc: A recalculation procedure was used for the aquatic species expected to occur in these segments of the Eagle River. After extensive review of available biological data and toxicity information, the recalculation was based on the following four most sensitive species that are expected to occur in these segments of the Eagle River: Cottus bairdi (Mottled Sculpin), Oncorhynchus (Rainbow and Cutthroat Trout), Salmo trutta (Brown Trout) and Ranatra elongata (Water Scorpion). The resulting site-specific recalculated hardness-based equations are:
Acute = 0.978*e0.8537[ln(hardness)]+1.4189
Chronic = 0.986*e0.8537[ln(hardness)]+1.2481
Because these equations rely on Sculpin as the most sensitive species, they are referred to as "sculpin equations." An attainability analysis was conducted which showed that it is not feasible to achieve a level of cleanup that would result in attainment of the sculpin equations in Segments 5a, 5b and 7b on a year-round basis. Additional remediation projects have been identified that can be performed at the site. The analysis shows that the identified remediation projects can be expected to result in additional zinc load reduction during March and April, when metals' loading is at its peak. When compared with the species toxicity information, it is clear that the feasible reductions still result in zinc levels that would exceed the standards based on the sculpin equation at some locations during some months. A modified species list without sculpin provided an equation that is based on the following four most sensitive species: Oncorhynchus (Rainbow and Cutthroat Trout), Salmo trutta (Brown Trout), Ranatra elongata (Water Scorpion) and Limnodrilus hoffmeisteri (Worm). The resulting recalculated hardness-based equations are:
Acute = 0.978*e0.8537[ln(hardness)]+2.1302
Chronic = 0.986*e0.8537[ln(hardness)]+1.9593
Because these equations rely on rainbow trout as the most sensitive species, they are referred to as "rainbow equations."
The biological goal for the Eagle Mine Superfund Site is a healthy brown trout fishery. Concurrent biological and water quality monitoring has shown that to achieve that goal, zinc must be maintained at levels better than those indicated by laboratory-based zinc toxicity studies with brown trout, probably because of combined effects with copper. On-going monitoring suggests that zinc and copper levels currently achieved by the cleanup are too high in March and April to maintain a healthy brown trout population. The equations based on a modified species list (rainbow equations) are incrementally more stringent than the equations based on brown trout and, at this site, offer a way to address this uncertainty and provide an adequate buffer for brown trout. These levels cannot be attained without additional remediation at the Eagle Mine Superfund Site.
The equations which represent the highest attainable water quality were applied by the Commission when and where the attainability analysis indicated they could be met. The rainbow equations were applied by the Commission to Segments 5a year-round and to segments 5b and 7b from January 1 through April 30. The sculpin equations were applied by the Commission to segment 5c year-round and to segments 5b and 7b from May 1 through December 31.
Copper: Similar to zinc, a recalculation procedure was conducted based on the species that are expected to occur at the site. The resulting species list includes the following as the four most sensitive species: Ephoron virgo (Mayfly), Tubifex tubifex (Worm), Plumatella emarginata (Bryozoan), and Oncorhynchus (Rainbow and Cutthroat Trout). The resulting recalculated hardness-based equations are:
Acute = 0.96*e0.9801[ln(hardness)]-1.5865
Chronic = 0.96*e0.5897[ln(hardness)]-0.4845
Because these equations rely on Ephoron virgo as the most sensitive species, they are referred to as "Ephoron equations." These recalculated copper standards are attainable and were applied to Segments 5b, 5c and 7b.
For Segment 5a, an attainability analysis was conducted which showed that it is not feasible to reduce copper loads to a level that would result in attainment of the Ephoron equations. The majority of the copper load originates from upstream sources that cannot be controlled at the site. A modified species list, without Ephoron provided an equation that is based on the following four most sensitive species: Tubifex tubifex (Worm), Plumatella emarginata (Bryzoan), Oncorhynchus (Rainbow and Cutthroat Trout and Lumbriculus variegatus (Worm). The resulting modified hardness-based equations are:
Acute=0.96*e0.9801[ln(hardness)] - 1.1073
Chronic=0.96*e0.5897[ln(hardness)] - 0.0053
Because these equations rely on tubifex worms as the most sensitive species, they are referred to as "tubifex equations." The tubifex equations were applied to Segment 5a.
Cadmium: The Commission had previously established an acute cadmium equation "with trout" in Regulation 31. That standard already applies to Segments 5a, 5b, 5c and 7b and continues to be appropriate and attainable. Therefore, no changes were made to the acute cadmium standard. However, using a revised acute/chronic ratio that was previously approved by both EPA and the Colorado Division of Wildlife for the Arkansas River and adopted by the Commission, a revised chronic cadmium equation was derived, as follows:
Chronic = (1.101672-[(ln(hardness)*(0.041838)])* e(0.7998 [ln hardness)]-3.1725)
This site-specific chronic Cadmium equation was applied to Segments 5a, 5b, 5c and 7b.
Jackson County Water Conservancy District proposed an ambient quality-based total recoverable iron standard of 1,845 ug/L for North Platte River Basin segments 3, 4 and 5b. This proposal was withdrawn prior to the rulemaking hearing; however, the Commission does recognize that the Coalmont Formation that underlies the North Platte Basin is a source of geologic iron. However, there is a need for additional information to fully characterize current iron levels and establish what anthropogenic factors might be at play. The Commission urges the Jackson County Water Conservancy District to work with the Division to re-examine the segmentation and develop information to support a joint proposal for ambient quality-based total recoverable iron standards where appropriate for the next basin-wide review in 2013.
The Commission adopted a CS-II temperature standard for Segment 13b. The Commission adopted WS-II temperature standards for Segments 13d and 13e, while recognizing that uncertainty remains due to limited data about temperature and the aquatic community. It is the Commission's intent that the Division, Seneca and other interested parties work to resolve the uncertainty for these segments by the next basin-wide review. (See Section L)
The Commission also granted type iii temporary modifications for total recoverable iron set at "existing quality" for Segments 13d and 13e (expiration: 5/31/2011). The uncertainty is based on whether the high ambient levels of iron in these segments are caused by natural or irreversible man-induced causes. It is the intention of the parties to preserve the status quo during the term of the temporary modification, i.e., Seneca will not change its operations so as to adversely affect the quality of its discharges for total recoverable iron.
The USFS conducted a reasonable level of inquiry to identify the recreational uses on First and Elkhead Creeks and presented their findings in a Recreation UAA. This information showed that no existing primary recreation uses are occurring on portions of segment 20, nor is there the potential for primary contact recreation uses to occur on these same reaches. Therefore, the Commission established a new segment 20b with a Recreation N classification (E. coli=630/100mL), based on changes in stream access and use characteristics. This new segment consists of the mainstem of First Creek from the eastern boundary of state lands in California Park to the confluence with Elkhead Creek as well as the mainstem of Elkhead Creek from the eastern boundary of state lands in California Park to the National Forest boundary. Consequently, the Commission revised the segment description of 20a, to exclude specific listings in segment 20b. In addition, the Commission revised the Recreation use classification of segment 20a from Class 1a to Recreation Class U (E. coli=126/100mL), due to the lack of a reasonable level of inquiry about existing recreational uses and a lack of a completed use attainability analysis having been completed for this segment.
PARTIES TO THE RULEMAKING
5 CCR 1002-33.44