5 Colo. Code Regs. § 1002-34.32
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
Some renumbering and/or creation of new segments in the basin was made due to information which showed that:
Animas River Basin segment 12c was created for Hermosa Creek and tributaries above Long Hollow, except for the East Fork of Hermosa Creek. The East Fork of Hermosa Creek was excluded from this segment due to uncertainty of future development in this drainage by Durango Mountain Ski Resort.
La Plata River Basin segment 4b was created for Mancos Reservoir (a.k.a. Jackson Gulch Lake).
La Plata River Basin segment 6c was created for waters within Mesa Verde National Park. These waters were proposed as "outstanding waters."
La Plata River Basin segment 8c was created for the Unnamed Tributary to Ritter Draw.
Dolores River Basin segment 4b was created for McPhee Reservoir and Summit Reservoir.
The Commission reviewed information regarding existing aquatic communities. There were no changes to the Aquatic Life Use Classifications in the San Juan Basin.
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 changed the following segments from Recreation Class1a to Recreation Class E with a 126/100 ml E. coli standard:
San Juan River Basin segments: 1, 2, 4, 5, 6a, 6b, 8, 9a, 9b and 10
Piedra River Basin segments: 1, 4a and 4b
Los Pinos River Basin segments: 1, 2a, 2b, 3, 4a, 4b, 5, 6a, 6b, 7a, 7b
Animas River and Florida River Basin segments: 1, 2, 3a, 3c, 4a, 4b, 5a, 5b, 6, 7, 8, 9, 10, 11a, 11b, 12a, 12b, 13a, 13b, 13c, 14 and 15
La Plata River Basin segments: 7a, 7b, 8a, 8b, 9, 10a, 10b and 11
Dolores River Basin segments: 1, 2, 3, 4a, 5, 6, 7, 8, 10, and 11
The following segments were converted from Recreation Class 1b to Recreation Class P with a 205/100 ml E. coli standard:
Piedra River Basin segments: 6a and 6b
La Plata River Basin segment: 1
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:
La Plata River Basin segments: 3a and 3b
The following segments with seasonal Recreation Class 1a/Recreation Class 2 classification were converted to Class E/Class N (some include changes to the seasons in parentheses):
San Juan River Basin segments: 11a and 11b
Piedra River Basin segments: 2, 3, (new seasons are Class E: April 1-Oct. 31, Class N: Nov. 1-March 31) 5 and 7
Animas River and Florida River Basin segment: 3b
La Plata River Basin segments: 2a, 4a, 5a and 5b
Dolores River Basin segment: 9
The following segments with seasonal Recreation Class 1a/Recreation Class 1b classification were converted to Class E/Class P(some include changes to the seasons in parentheses):
La Plata River Basin segment: 2b
The following segments with seasonal Recreation Class 2/Recreation Class 1b classification were converted to Class N/Class P:
San Juan River Basin segments: 3, 12a and 12b
La Plata River Basin segments 6a and 6b
Based on review of information regarding the location of public water supplies, no additional WS classifications and standards were added to Regulation No. 34.
Numeric Standards to protect Agricultural Uses were adopted for the following segments:
San Juan River Basin segments: 12a and 12b
Los Pinos River Basin segments: 7a and 7b
La Plata River Basin segments: 10a and 10b
Outstanding Waters Designation: Based on evidence that shows the water quality meets the requirements of 31.8(2)a, the OW designation was added to the following segments in Mesa Verde National Park: Segment COSJLP06c was created for waters within Mesa Verde National Park.
Based on evidence that shows the water quality meets the requirements of 31.8(2)(a), the OW designation was added to Hermosa Creek and its tributaries (except the East Fork of Hermosa Creek) above Long Hollow. A new segment, Segment COSJAF12c was created for these waters. The Commission understands that there are existing land uses, including grazing permits, in place in the watershed. The evidence demonstrates that these existing land uses are compatible with the Outstanding Water 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.
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:
Los Pinos River Basin segments: 6a, 6b, 7a and 7b
Animas River and Florida River Basin segments: 13a, 13b, 13c and 15
La Plata River Basin segment: 2a
Dolores River Basin segments: 9 and 11
Decoupling Aquatic Life Warm 2 and UP Also as part of the Basic Standards hearing of 2005, the Commission decided that the presence of a warm water class 2 classification would still be a presumptive basis for applying a use-protected designation; however, that presumption can be overcome if there is data showing that the water is of high quality. Therefore, the Commission reviewed all warm water class 2 segments to determine if the use protected designation is still warranted. The following segment is now reviewable:
San Juan River Basin segment: 3
There are several segments in the Basins that are assigned standards based on existing ambient water quality. 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 Commission did not adopt any changes to the ambient quality-based standards.
At the June 2005 Basic Standards rulemaking, the Commission adopted the 1999 Update of Ambient Water Quality Criteria for Ammonia (US EPA, Office of Water, EPA-822-R-99-014, December 1999) as the numeric ammonia criteria for Colorado. These new criteria are in the form of total ammonia rather than un-ionized ammonia. The Commission modified the ammonia equations in 34.6(3) and footnotes to conform to Regulation No. 31. In cases where dischargers need time beyond one permit term to assure compliance with new permit limits, temporary modifications have been adopted. These are listed below in the temporary modification section.
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 34.6(3) were modified to conform to Regulation No. 31.
Site-Specific Zinc Standards for Sculpin: In low hardness situations (hardness below 113 mg/L) the new zinc equation is not protective of sculpin, a native west-slope fish species. The Commission adopted sculpin-specific zinc equation as site-specific standards for the following segments that are inhabited by sculpin that also have low hardness:
San Juan River Basin segments: 5, 6a and 9a
Piedra River Basin segments: 2, 3, 4a and 5
Los Pinos River Basin segments: 2a and 4a
Animas River and Florida River Basin segment: 10
La Plata River Basin segments 1 and 2a
Dolores River Basin segments: 1, 2, 5, 7 and 11
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) |
Uranium standards were not added for any segments in this basin.
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 are being removed because there are no discharge permits on these segments. Non-attainment of underlying standards shall be addressed through listing and prioritization of TMDLs or through implementation of approved TMDLs:
La Plata River Basin segment 4a: (Cu)
Dolores River Basin segment 9: (Zn)
The following segments have new or extended temporary modifications. 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.
San Juan River Basin segment 11a: Fe(ch)=1100 ug/l; expiration date 12/31/2011. This temporary modification is intended to allow Pagosa Area Water and Sanitation District (Snowball WTP) adequate time to assess any potential changes to its discharge permit. This need for this temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 3a: Fe(ch)=1920 ug/l; expiration date 12/31/2011. This temporary modification is intended to allow a discharger adequate time to assess any potential changes to its discharge permit. This need for this temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 5a: NH3 = old TVS, expiration date 12/31/2011; This temporary modification is intended to allow the dischargers such as the Town of Mancos adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 7a: NH3 = old TVS, expiration date 12/31/2011; This temporary modification is intended to allow the dischargers such as the City of Cortez adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 8a: NH3 = old TVS, expiration date 12/31/2011; Fe(ch)=1500 ug/l; expiration date 12/31/2011. These temporary modifications are intended to allow the dischargers such as the City of Cortez and Dove Creek adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010.
La Plata River Basin segment 8c: NH3 = existing quality, expiration date 12/31/2013; This temporary modification is intended to allow Lee Mobile Home Park adequate time to assess any potential facility changes that will be required to assure compliance with new ammonia limits. This temporary modification will be reviewed in 2009 and 2010.
The Upper Animas River Basin is a historic mining region undergoing remedial efforts led by the Animas River Stakeholder Group. There are approved TMDLs for the basin that cover all segments and parameters that are in non-attainment of water quality standards. Due to historic mining there are numerous other point-source discharges to nine segments in the Upper Animas River Basin that are not currently permitted. The Commission decided to retain and update temporary modifications to the historic mining impacted segments to allow flexibility in remedial efforts.
Animas River Basin segment 2: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 3a: Cd(ch)=3.0, Mn(ch)=3203, Zn(ch)=862. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 3b: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 3c: Cu(ch)=6.6, Zn(ch)=184, no Cu, Zn acute. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 4a: Al(ch)=2523 (trec), Fe(ch)=4204 (trec), Zn(ch) = 730 ug/L, Cu(ch) = 20 ug/L; Cd(ch) = 2.5 u/L, pH= 5.3; expiration date 12/31/2011. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 4b: Zn(ch)=184. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 7: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 8: Existing ambient quality for all metals. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
Animas River Basin segment 9: Al(ch)=3544(Trec), Cu(ch)=22, Fe(ch)=5023(Trec), Zn(ac/ch)=340. This temporary modification is intended to allow the TMDL directed remedial efforts adequate time to address non-attainment of standards. This need for this temporary modification will be reviewed in 2009 and 2010.
The hearing of section 34.5 has changed to "Indian Reservations"as a more accurate description. In addition, the test of this section was revised to reflect EPA's approval of the Ute Mountain Utes' treatment as a state status for the adoption of water quality standards.
The Commission corrected several typographical and spelling errors, and clarified segment descriptions.
The reference to "Water+Fish Organics" was corrected to "Water+Fish Standards"to incorporate the appropriate standards from both the organics table and the metal parameter table in Regulation No. 31.
The segment description for Piedra segment 5 was changed to include "Williams Creek Reservoir."
The segment description for Dolores segment 5 was changed to include "Groundhog Reservoir."
Acute copper and zinc TVS were added to the table for Animas River segment 3c.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-34.32