Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-34 - REGULATION NO. 34 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR SAN JUAN AND DOLORES RIVER BASINS
Section 5 CCR 1002-34.29 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; MAY, 2001 AND JULY, 2001 RULEMAKING
Current through Register Vol. 47, No. 5, March 10, 2024
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
I. Animas and Florida River Segments
The primary focus of this portion of the hearing was to revisit the aquatic life classifications and standards for streams in the Animas River Basin that have elevated levels of various metals. The water quality of this area is extensively impacted by heavy metals which are attributed to both natural and anthropogenic sources. Those impacts attributed to past human activities are largely the result of the extensive mining that has occurred in this basin over a period of several decades. It is evident that remediation of these impacts is a complex challenge that will require considerable time and effort.
Subsequent to the last major review of these streams, a use attainability analysis (UAA) was prepared by the Animas River Stakeholders Group (ARSG). Over the last several months, this UAA has provided the focal point for extensive discussions involving the Water Quality Control Division, the Colorado Division of Wildlife, U. S. EPA, the U.S. Forest Service, the U. S. Bureau of Land Management, and other participants in the stakeholders group. The Commission wishes to acknowledge and express its appreciation for this extensive collaborative effort. The Commission believes that the revised Animas River Basin classifications and standards adopted as a result of this hearing provide a major step forward in the long-term resolution of water quality issues in this basin. The Commission encourages all of those involved in this effort to continue to work cooperatively in furthering ARSG's mission of improving the water quality in the Animas River and its tributaries.
Upper Animas Segmentation
The Commission adopted several changes to the segmentation for streams in the Animas River Basin. The Commission changed descriptions for several segments to correct inaccuracies and to include tributaries previously left out of descriptions. The Commission changed the segment division between segments 4b and 5a to better reflect a natural division between the segments in terms of topography, geomorphology and land use patterns. The Commission also moved the dividing line between segments 4a and 4b upstream to Deer Park Creek, which is the first significant inflow of good quality water below the confluence with Mineral Creek. The streams formerly in segment 9a have been moved to segment 6, and the previous segment 9b renumbered as segment 9. Finally, recognizing the need for a new segment to cover a tributary to the Animas River not previously classified, the Commission created segment 3c to include Arrastra Gulch and applied site-specific standards as described below. Big Horn Creek and all tributaries on the west side of Mineral Creek above its confluence with South Mineral Creek except for a lower portion of Middle Fork of Mineral Creek and the mainstem of Mineral Creek (segment 8), were reclassified as part of segment 6.
Overview of Aquatic Life Classifications and Standards
The UAA focused primarily on identifying the achievable remediation and associated water quality for segments 3a, 4a, and 9b (now segment 9) of the Animas. Some of the metals standards previously adopted for these segments were disapproved by EPA in 1998. The UAA identified the water quality that would result from remediation of selected priority sites where metals loadings were determined to be anthropogenic and reversible. Based upon this analysis, and the associated biological evidence submitted, the Commission revised the aquatic life classifications for segment 9b (now segment 9) and for resegmented segment 4a. In addition, the Commission has specified aquatic life indicators in the "goal qualifier" column for these three segments. These indicators identify biological goals for future water quality in these segments.
Numerical standards for these three segments adopted at this time are based on the conclusions of the UAA regarding what remediation is achievable. In some cases, identified remediation goals are expected to attain Table Value Standards. In other cases, site-specific standards are adopted based on the UAA's projections of what water quality will be attained at specific gages in the three key segments as a result of anticipated remediation. Remediation potentials and limitations have been explored in great detail and the resulting site-specific standards are scientifically defensible, recognizing, however, that there is significant uncertainty as discussed below. The standards are reflective of ambitious cleanup goals estimated at a cost of 20 to 30 million dollars. The goals are particularly ambitious given foreseeable funding availability and liability restrictions that may detrimentally affect remediation activity (e.g. there remains a lack of a "Good Samaritan" provision in the federal Clean Water Act).
The Commission also notes that additional information appears to be needed to determine attainable/protective water quality conditions in this basin over the long term. There is more than the usual amount of uncertainty associated with the various proposals considered in this hearing. There is uncertainty associated with the remediation targets because there may be additional reversible anthropogenic sources which have not yet been identified or fully characterized. There is uncertainty associated with the biological targets, because for some parameters there is a lack of toxicity data for key species of concern. In view of these uncertainties, the Commission emphasizes the importance of ongoing monitoring efforts and future studies in the Animas Basin to resolve the important issues that have been identified. It is the Commission's expectation that these efforts will proceed and will lead to refinement in the remediation goals in the basin, and in the associated determination of attainable water quality classifications and standards, in the future triennial reviews. Again, the Commission wishes to commend the cooperative efforts and the substantial local initiative that have brought the analysis to this stage. The Commission strongly encourages continued cooperation as these challenges are addressed in the future.
Site-specific Aquatic Life Classifications and Standards
When segment 9b (now segment 9) was designated aquatic cold water class 1 in 1995, there was little or no data indicating that dissolved aluminum concentrations and total recoverable iron concentrations reached toxic levels because few or no winter water quality samples had been taken. Winter water quality samples taken since that time indicate dissolved aluminum concentrations almost three times the acute table value standard for aquatic life and total recoverable iron concentrations have been found to be four times the chronic table value standard for aquatic life. The Commission determined that the vast majority of sources of aluminum and iron are not associated with mining sites identified for remediation. In addition, the Commission heard testimony that no fish and few macroinvertebrates are found in segment 9b (now segment 9). Therefore, the Commission changed the use classification of cold water aquatic life class 1 to cold water aquatic life class 2 for segment 9b (now segment 9). Site-specific standards are applied for iron, aluminum, copper, and zinc based upon remediation goals presented by the ARSG.
The Commission determined that after remediation of identified priority loading sources, aluminum, iron, and copper concentrations will continue to exceed chronic table value standards for aquatic life during portions of the year in segment 4a. The Commission also determined that after remediation, zinc concentrations will continue to exceed acute and chronic table value standards for aquatic life year round. Based on this information, the Commission removed the use classification goal of cold water aquatic life class 1 from segment 4a and retained the use classification of cold water aquatic life class 2. Site-specific standards are applied for iron, aluminum and zinc based upon remediation goals presented by the ARSG.
In addition, the Commission recognized that there are few identified priority sources of cadmium, manganese, and zinc in or upstream of segment 3a. These constituents will continue to exceed aquatic life table value standards either year-round or during part of the year after remediation of the reversible sources. The UAA did not identify the large amount of metal loading entering segment 3a with any specific source. The Commission recognized the many unknowns and uncertainties in the analysis of source loadings in segment 3a. Therefore, the Commission applied site-specific standards based upon remediation goals to segment 3a for these constituents and encouraged the ARSG to continue their characterization efforts to determine the unknown sources of loading. The aluminum standards for segments 3a, 4a and 9 have been specified as "total recoverable", since that sampling fraction correlates better with the principal aquatic life toxicity studies available than the dissolved fraction.
As noted above, the Commission has adopted a new segment 3c for Arrastra Gulch, with a cold water aquatic life class 2 classification.The existing ambient quality for copper and zinc exceed the acute table value standards, therefore, chronic ambient standards could not be adopted. Acute table value standards for copper and zinc were adopted along with temporary modifications set at existing ambient quality. This provides time for the ARSG to investigate Arrastra Gulch and prepare appropriate chronic standards at the next triennial review.
During the hearing, the Commission heard evidence that iron is a major driver in the chemical processes that lower pH. The Commission determined that because most iron sources are not associated with priority remediation sites in the Upper Animas Basin, for some segments and some portions of the year, pH levels are unlikely to reach table value standards for aquatic life with remediation of mine sites. Therefore, the Commission applied seasonal, site-specific pH standards to segments 4a and 9b (now segment 9).
The adopted standards will protect existing aquatic populations and should allow for significant increases in biological diversity, population size, and aquatic health. At this time, there is no assurance that other human-caused conditions or sources of pollution preventing the attainment of Table Value Standards and higher uses can be remedied, given current technologies and regulatory conditions; nor is there assurance that additional remediation will not be feasible in the future. Particularly in view of the uncertainty noted above, as these restrictions to further water quality improvements change it will be necessary to review additional remediation possibilities and to implement standards reflective of these possibilities at future triennial reviews.
Temporary modifications were reviewed and extended to December 31, 2006 for segments 2, 3b, 7, 8 and 9.
Other Classification and Standards Issues
The following resegmentation was adopted:
Animas and Florida, Segment 11: Mainstem of Florida River was separated into Segments 11a and 11b to recognize the Southern Ute Indian Reservation boundary.
Animas and Florida, Segments 13b and 13c: These segment descriptions were clarified to recognize the Southern Ute Indian Reservation boundary. This change in descriptions corrects the duplicate classification of these tributaries.
Animas and Florida, Segments 15: Cascade Creek was deleted from the segment description. Cascade Creek now is included in Segment 12a which better reflects its cold water class 1 aquatic life use.
Animas/Florida segment 1 was designated outstanding waters (OW) due to its meeting the criteria in section 31.8(2)(a).
Ambient quality-based standards were removed from the following segments due to new data and/or changes to the Basic Standards which indicated ambient standards were no longer appropriate: segments 2, 3a, 3b, 4a, 4b, 7, 8, 9b.
"Fish Ingestion" and "Water + Fish Ingestion" standards for organic chemicals are discussed in section II.J. of this Statement of Basis and Purpose. For the Animas and Florida Rivers, Fish Ingestion standards were adopted for segment 13a and Water + Fish Ingestion standards were adopted for segments 13b and 13c.
Animas/Florida River, segments 13b, 13c where investigation showed that aquatic life was present were upgraded with the addition of the full suite of inorganic standards to protect aquatic life.
Water supply classifications and associated standards were adopted for segments 11b, 13b and 13c.
Agriculture classifications are added to segment 4a and to the new segment 3c based on existing or potential grazing uses. In addition, numerical standards are adopted to protect the existing agriculture classifications for segments 2, 7, and 8. In each case, no manganese standard was adopted, because the conditions associated with that criterion are not present.
Recreation classifications were changed from class 2 to class 1a for segments 2, 3a, 3b, 6, 7, 8, 9a, 9b, 13a, 13b, 13c, and 15. For several of these segments, the Southwestern Water Conservation District submitted use attainability analyses proposing that a recreation class 2 classification be retained. However, these UAAs were submitted after the deadline for submission of such information for this hearing and generally lacked site-specific analysis of recreation uses on the segments addressed. Existing recreation class 1 classifications were changed to class 1a for segments 1, 4a, 4b, 5a, 5b, 10, 11a, 12a, 12b, and 14. A recreation class 1a classification was also adopted for new segment 11b.
The Commission notes that the last paragraph of section 31.6 will apply to future changes to the recreation classifications where a proper showing is made through a use attainability analysis that a recreation class 2 classification is appropriate, without application of the other downgrading criteria in this section. Moreover, the Commission is relying in part on previous representations from EPA that completion of a use attainability analysis showing that a lower recreation classification is appropriate satisfies applicable downgrading criteria. Based on these factors, the Commission intends that in a future rulemaking hearing the test for adopting a recreation class 2 classification would be the same as if it had been considered in this hearing.
Based on evidence submitted by the Town of Silverton, the Commission established a seasonal recreation class 1a classification for segment 3b, for the period of May 15 through September 10 and recreation class 2 for the remainder of the year.
II. Other River Segments
Some segments were renumbered and/or created in the basin due to information which showed that:
San Juan, Segment 8: This segment was created to recognize the portions of Navajo Reservoir that are on state lands.
San Juan, Segments 11 and 12: Tributaries to the San Juan River were separated out of Segments 11 and 12 to better identify the tributaries from Fourmile Creek to the Southern Ute Indian Reservation (11a) and from the Southern Ute Indian Reservation to the Colorado/New Mexico border (11b). All remaining tributaries to the San Juan River in Archuleta County were moved to Segments 12a and 12b. Segment 12b is within the Southern Ute Indian Reservation.
Los Pinos, Segment 6b: All remaining tributaries to the San Juan River in La Plata County were moved to Segments 7a and 7b. Those within the Southern Ute Indian Reservation are in Segment 7b.
La Plata, Segment 2b: The segment description was modified to only include the mainstem of the La Plata River. Wetlands, lakes and reservoirs to the La Plata River are now included in Segments 10a and 10b with their tributary systems.
La Plata, Segment 7: Mainstem of McElmo Creek was separated into Segments 7a and 7b to recognize the Ute Mountain Ute Indian Reservation boundaries. In addition, Yellowjacket Creek was added to Segment 7a from Segment 8 to better reflect its warm water class 1 aquatic life use.
La Plata, Segments 8 and 10: Tributaries to McElmo Creek were separated into Segments 8a and 8b to recognize the Ute Mountain Ute Indian Reservation boundaries.
La Plata, Segments 8 and 10: All remaining tributaries to the San Juan River in Dolores and Montezuma Counties were moved to Segments 10a and 10b. The portions within the Ute Mountain Ute Indian Reservation are included in Segment 10b.
Dolores, Segment 7: The segment description was changed to exclude the upper portion of Coal Creek which is located within the Lizard Head Wilderness Area.
The aquatic life manganese criterion was initially changed in the 1997 revisions to the Basic Standards (5 CCR 1002-31) from a single chronic dissolved criterion to acute and chronic hardness-based equations. The equations were further modified in the 2000 revisions to the Basic Standards. The new manganese acute and chronic equations were added as table value standards in 34.6(3). As a result of the adoption of these new TVS, all segments classified for aquatic life use that had a chronic total recoverable manganese standard of 1,000 µg/L had the 1,000 standard stricken and replaced with Mn(ac/ch)=TVS.
The regulation in 34.6 (3) listed the table value standards for selenium as Acute=135 µg/L and Chronic=17 µg/L. This was updated to reflect the existing acute and chronic criteria for selenium listed in the Basic Standards as Acute=18.4 µg/L and Chronic=4.6 µg/L which was adopted in 2000 by the Commission. This change means that all segments with standards for selenium given as TVS now have these lower acute and chronic standards. Because of this change, on all segments classified for a water supply use, the chronic total recoverable selenium of 10 µg/L was stricken and replaced with Se(ac/ch)=TVS.
Several segments or waterbodies were designated outstanding waters (OW) due to their meeting certain criteria pursuant to section 31.8 . Segments which already included wilderness areas in their description were designated OW. The water quality of the following segments met the 12 parameter test and other requirements of 31.8(2)(a):
San Juan River, Segment 4
Piedra River, Segment 1
Los Pinos River, Segment 1
Dolores River, Segment 1
The Division proposed that a number of aquatic life class 2 waterbodies be assigned undesignated status under the state antidegradation regulation due to the presence of Colorado State species of special concern. State regulations governing the "use-protected" designation allow this exception if the Commission determines that the waters are of exceptional ecological significance. The Commission believes that a number of important issues have been raised in this hearing regarding when and how this exception should be applied, and that further examination of these issues should occur. Nevertheless, for purposes of this hearing, the Commission, based upon a concern over the protection of classified uses and the absence of evidence of potential injury to permitted entities, has decided to accept the change to reviewable water status for the following
San Juan River, Segment 10
La Plata, Segments 5a, 5b, 6a and 6b.
Based upon representations made by certain parties to this rulemaking, the Commission endorses the formation of a workgroup to address the following topics and develop recommendations to be submitted to the Commission
* The relationship between the "exceptional ecological significance" exception to use-protected designations and the aquatic life class 2 basis for applying use-protected designations
* The need for and content of guidance to determine what water bodies are exceptionally ecologically, significant
* The roles of a) water quality data; b) the nexus between water quality conditions and species decline, and c) other stressors
* The need for and nature of any amendments to the state antidegradation regulation if the presence of species of special concern constitute a basis for modification to the antidegradation designation of a water body.
The above listed segments would then be reviewed in light of the work group recommendations in the next triennial review of these basins.
The Commission urges that the work group process to address these issues move forward as expeditiously as possible. The Commission intends that the actions taken in this rulemaking not serve in any way as a precedent with respect to decisions in future Commission rulemaking proceedings.
The biological standards were updated to include the dual standards for E. coli and fecal coliform, which were adopted by the Commission in the 2000 revisions to the Basic Standards. As stated in the statement of basis for the Basic Standards revisions, the Commission intends that dischargers will have the option of either parameter being used in establishing effluent limitations in discharge permits. In making section 303(d) listing decisions, in the event of a conflict between fecal coliform and E. coli data, the E. coli data will govern. The Commission believes that these provisions will help ease the transition from fecal coliform to E. coli standards.
In a continuation of the Commission's efforts to comply with the requirements contained in the federal Clean Water Act that all waters of the nation should be suitable for recreation in and on the water (known as the "swimmable" goal), the Commission reviewed all Recreation Class 2 segments. In Colorado, the "swimmable" goal translates into Recreation Class 1a, with the 200/100 ml fecal coliform and 126/100 ml E. Coli standard, and Class 1b with the 325/100 ml fecal coliform and 205/100 ml E. coli standard. Class 1a indicates waters where primary contact uses have been documented or are presumed to be present. Class 1b indicates waters where no use attainability analysis has been performed demonstrating that a recreation class 2 classification is appropriate, but for which no existing primary contact uses have been documented following a reasonable level of inquiry. To maintain the existing Recreation Class 2 with the 2000/100 ml standard on a segment, a use attainability analysis must be conducted that shows that it is unlikely that a Recreation Class 1 activity could exist.
There was considerable evidence and testimony submitted in this hearing regarding what activities should be considered primary contact recreation. Section 31.13 of the Basic Standards provides a non-exclusive list of primary contact activities. In this hearing, much discussion focused on the issue of whether "child's play" in streams that are too shallow to accommodate the primary contact uses listed in the Basic Standards should be considered a primary contact use. The Commission does not believe that a theoretical potential for child's play means that all streams should be classified Recreation Class 1a or 1b. However, the Commission concludes that the evidence submitted demonstrates that there is a potential risk of ingestion of small quantities of water by children playing in relatively shallow streams, based on the hand-to-mouth pathway, which warrants Recreation Class 1 protection in appropriate circumstances as elaborated below. Thus, such ingestion may occur in streams where whole body immersion is not likely.
This does not mean, as suggested by some, that all water bodies would be reclassified as Recreation Class 1a or 1b based on some potential for child's play. Rather, the Commission intends that a stream should be classified Recreation Class 1a or 1b due to the presence or potential for child's play only where the evidence demonstrates a likelihood of such activity on a frequently occurring basis. Therefore, child's play may be an appropriate basis for a Recreation Class 1a or 1b classification in a developed area where there is easy access to a stream for children and it is likely that children will desire to play in the stream; it may not be an appropriate basis for such classifications in areas where it is not expected that children will be playing in a stream on a frequently occurring basis. Factors such as lack of adequate flow, excessive flows, remoteness from developed areas, physical limitations to access, steep banks, and visibly poor water quality may make it unlikely that child's play will take place on a frequently occurring basis.
The Commission anticipates that these classification decisions will require case-by-case judgments until more experience is gathered with this issue.
A recreation Class 1a or 1b classification of a segment is not intended to imply that the owner or operator of property surrounding any waterbody in a segment would allow access for primary contact recreation. The application of recreation classifications to state waters pursuant to these provisions does not create any rights of access on or across private property for the purposes of recreation in or on such waters. A recreation Class 1a classification is intended to only affect the use classification and water quality standards of a segment, and does not imply public or recreational access to waters with restricted access within a segment.
For segments changing to recreation Class 1a because no information was available about actual recreational uses, the last paragraph of section 31.6 will apply to future changes to the recreation classification where a proper showing is made through a use attainability analysis that a recreation Class 2 classification is appropriate, without application of the other downgrading criteria in this section. Moreover, the Commission is relying in part on the testimony from EPA that completion of a use attainability analysis showing that a lower recreation classification is appropriate satisfies applicable downgrading criteria. Based on these factors, the Commission intends that in a future rulemaking hearing, the test for adopting a recreation Class 2 classification would be the same as if it had been considered in this hearing.
Based on the information received that showed Recreation Class 1a uses are in place or are presumed to be present in at least a portion of the segment, the Commission changed the following segments from Class 2 to Class 1a with a 200/100 ml fecal coliform and 126/100 ml E. coli standard:
San Juan River, Segments: 10
Los Pinos River, Segments: 6a, 6b
Dolores River, Segments: 2, 3, 5, 6, 7, 8, 11
Based on the information received, where a reasonable level of inquiry failed to identify any existing class 1 uses of the waters in these segments, the Commission changed the following segments to Class 1b with a 325/100 ml fecal coliform and 205/100 ml E. coli standard:
Piedra River, Segments: 6a, 6b
New segments created in this rulemaking where information was received that showed Recreation Class 1a uses are in place or are presumed to be present in at least a portion of the segment, are:
San Juan River, Segment: 8
Los Pinos River, Segments: 7a, 7b
La Plata River, Segments: 7b, 8a, 8b, 10a, 10b
The following segments with existing Recreation Class 1 classifications were changed to Class 1a:
San Juan River, Segments: 1, 2, 4, 5, 6a, 6b, 7, 9a, 9b
Piedra River, Segments: 1, 4a, 4b
Los Pinos River, Segments: 1, 2a, 2b, 3, 4a, 4b, 5
La Plata River, Segments: 1, 4, 7a, 9, 11
Dolores River, Segments: 1, 4, 10
For the following segments, the Commission adopted seasonal recreation classifications, based on evidence of differences in actual or potential uses at different times of the year
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San Juan Segments 3, 12a, 12b: |
Class 1b, May 1 through October 31 Class 2, November 1 through April 30 |
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San Juan Segments 11a, 11b: |
Class 1a, May 1 through October 31 Class 2, November 1 through April 30 |
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Piedra River, Segments 2, 3, 5: |
Class 1a, May 1 through October 31 Class 2, November 1 through April 30 |
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Piedra River, Segment 7: |
Class 1a, March 1 through November 30 Class 2, December 1 through February 28 |
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La Plata River, Segments 2a, 2b: |
Class 1a, May 1 through October 31 Class 1b, November 1 through April 30 |
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La Plata River, Segments 4, 5a, 5b: |
Class 1a, May 1 through October 31 Class 2, November 1 through April 30 |
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La Plata River, Segments 6a, 6b: |
Class 1b, May 1 through October 31 Class 2, November 1 through April 30 |
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Dolores River, Segment 9: |
Class 1a, May 1 through October 31 Class 2, November 1 through April 30 |
The following segments retained their Recreation Class 2 classification with 2,000/100 ml fecal coliform and 630/100 ml E. coli standards after sufficient evidence was received that a Recreation Class 1a use was unattainable, due to limited streamflows.
La Plata River, Segments 3a, 3b
The Commission reviewed information regarding Aquatic Life Class 2 segments where the full set of inorganic aquatic life protection standards have not been applied. Generally, these are dry segments with only rudimentary aquatic life. The Commission's policy has been that rather than adopt the full set of inorganic standards for these segments, standards for dissolved oxygen, pH and fecal coliform provide sufficient protection.
Segments where investigation showed that aquatic life was present were upgraded with the addition of the full suite of inorganic standards to protect aquatic life. These segments are:
San Juan River, Segments: 10, 11a,
11b Piedra River, Segments: 6a, 6b
La Plata River, Segments: 3a, 3b, 6a, 6b, 8a, 8b
Dolores River, Segment 11
There are several segments in the San Juan Basin that contain standards based on existing ambient quality. Ambient standards are adopted where natural or irreversible man-induced conditions result in water quality levels higher (i.e. worse) than table value standards. EPA had requested that the Commission review 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 Division reviewed the reason for the ambient standards and provided testimony that justified ambient standards being retained without adjustment on the following segments:
La Plata River, Segment 9
The Division reviewed the information about ambient water quality levels and provided testimony that justified revising the ambient standards on the following segments:
La Plata River, Segment 7a
Ambient standards were removed from the following segments due to new data and/or changes to the Basic Standards which indicated ambient standards were no longer appropriate:
Los Pinos River, Segment 5
River, Segment 9
There were several segments which had temporary modifications that were reviewed, and decisions were made to delete or to extend them, either as is or with modification of the numeric limits.
A temporary modification was adopted for La Plata, Segment 4, for copper with an expiration date of 12/31/06. A temporary modification was also adopted for Dolores River, Segment 9, for zinc with an expiration date of 12/31/06.
The organic chemical standards were updated to include changes adopted by the Commission in the 2000 revisions to the Basic Standards (see section 31.11 in Regulation No. 31). "Water + Fish" organic chemical standards are presumptively applied to all Aquatic Life Class 1 streams which also have a Water Supply classification, and are applied to Aquatic Life Class 2 streams which also have a Water Supply classification, on a case-by-case basis. The "Fish Ingestion" organic chemical standards are presumptively applied to all Aquatic Life Class 1 streams which do not have a Water Supply classification, and are applied to aquatic life class 2 streams which do not have a Water Supply classification, on a case-by-case basis. Existing site-specific applications of additional organics (as noted in the Qualifier column of Table 34.7) were modified to conform to this change.
Information was reviewed regarding Aquatic Life Class 2 segments that have fish that are presently being taken for human consumption or have fisheries that would indicate the potential for human consumption. That information showed that six additional segments had the potential for consumption of fish. These waterbodies were designated to receive the full protection of numeric Fish Ingestion or Water + Fish organic standards:
Fish Ingestion: La Plata 2a; Dolores 9
Water + Fish: Dolores 11
These segments had the Water Supply classification added to them or are new segments with a water supply use. The associated water supply standards will now apply to segments:
San Juan River, Segments: 6b, 8
River, Segments: 4b, 6a, 6b
Dolores River, Segment 11
Water supply standards were modified to conform to the changes made by the Commission in the 2000 revisions to the Basic Standards (see Regulation No. 31 at section 31.11). The Commission modified the water supply standards for iron, manganese, and sulfate that are based on secondary drinking water standards (based on aesthetics as opposed to human-health risks). The numeric values in the tables were changed to Fe(ch) = WS (dis), Mn(ch) = WS (dis), and SO4 = WS. These abbreviations mean that for all surface waters with an actual water supply use, the less restrictive of the following two options shall apply as numerical standards, as discussed in the Basic Standards and Methodologies at section 31.11 : either (i) existing quality as of January 1 2000; or (ii) Iron = 300 µg/L (dissolved); Manganese = 50 µg/L (dissolved); Sulfate = 250 mg/L (dissolved). For all surface waters with a "Water Supply" classification that are not in actual use as a water supply, no water supply standards are applied for iron, manganese or sulfate, unless the Commission determined as the result of a site-specific rulemaking hearing that such standards are appropriate.
Many of the waterbodies in the southern parts of these basins are located on tribally-owned lands specifically those of the Southern Ute Indian Tribe and the Ute Mountain Ute Indian Tribe.Waters on tribally-owned lands are not regulated by the WQCC. Both Tribes are in the process of developing water quality standards for waters on their tribally-owned lands. The Commission has segmented the waterbodies which cross reservation boundaries. Water quality standards for waterbodies crossing reservation boundaries were reviewed by the Division in cooperation with Tribal representatives to ensure that the classified uses and numeric standards were consistent. The Commission included water quality classifications and standards on lands within the boundaries of these reservations in agreement with the Southern Ute and Ute Mountain Ute Indian Tribes in order to avoid a gap in the classifications and standards adopted for the river basins in question, since these Tribes have not yet been granted authority by EPA to conduct their own water quality program. Section 34.5 was added to clarify this issue.
Numeric standards to protect agriculture uses were adopted for the following segments:
San Juan, Segment: 3
Los Pinos, Segments: 6a, 6b
The Commission corrected several typographical and spelling errors, clarified segment descriptions and made the following site-specific revisions:
La Plata, Segment 2a: The classification was changed from aquatic life warm 2 to cold 2 because information was presented that indicated the aquatic community includes trout species.
La Plata, Segment 7a: The classification was changed from aquatic life warm 2 to warm 1 and removed the Use Protection designation, because information was presented that indicated the aquatic community is diverse and includes DOW species of special concern.
PARTIES TO THE RULEMAKING HEARING
