5 Colo. Code Regs. § 1002-37.11
The provisions of 25-8-202 (1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402 C.R.S. 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:
First, the Commission has adopted new introductory language for the tables in section 3.7.6 The purpose of this language is to explain the new references to "table value standards" (TVS) that are contained in the Tables. These provisions also include the adoption of new hardness equations for acute and chronic zinc standards throughout the basin. Based on information developed since the "Basic Standards" were revised, these new equations have been determined to represent more appropriate zinc criteria. New information contained in a 1987 EPA zinc criteria document indicates Colorado's zinc criteria is overly restrictive, especially at hardness in the range of 50 to 200 mg/l. Adoption of the Colorado zinc criteria as site-specific TVS standards may potentially cause undue treatment costs to dischargers who would be regulated by those standards until they could be adjusted through a section 207 hearing or during the next round of basin hearings.
The existing criteria for zinc contained in the "Basic Standards" was developed by the Commission's Water Quality Standards and Methodologies Committee. At the time of development, the EPA zinc criteria document was not available. Because of some limited data indicating a consistent chronic toxicity level at water hardnesses of 200 mg/l or less, the Commission adopted a chronic criteria of 45 µg/l for hardness of 0 to 200 mg/l. This is much more stringent than EPA criteria which, as an example, specifies chronic zinc levels of 59 µg/l and 190 µg/l at hardness of 50 mg/l and 200 mg/l, respectively.
The Commission also has adopted additional organic chemicals standards for certain aquatic life segments. The standards added in section 3.7.5 (e) are based on water and fish ingestion criteria contained in the U.S. Environmental Protection Agency's Quality Criteria for Water, 1986 and updates to this document through 1989, which is commonly referred to as the "Gold Book". The standards are being applied to all class 1 aquatic life segments. The standards are based on a 10- risk factor.
The application of these standards to waters where actual or potential human ingestion offish is likely is important in assuring that Colorado achieves full compliance with the toxics requirement of section 303(c) (2) (B) of the federal Clean Water Act. It is reasonable to assume that most Class 1 aquatic life segments, because of their variety of fish species and/or suitable habitat, have the potential for fishing and the resultant human consumption of the fish or other aquatic life.
One other general issue should be addressed at the outset. Several parties to this proceeding submitted documents expressing concern regarding the adoption of high quality 2 designations because of potential impact on water rights held by these entities. The Commission transmitted these documents to the State Engineer and the Colorado Water Conservation Board to solicit any comments that they might have. In its transmittal letter, the Commission stated its preliminary assessment that the proposed adoption of high quality 2 designations did not present the potential to cause material injury to water rights.
The high quality designation merely indicates that an antidegradation review will be required for certain activities. In its regulations, the Commission has specifically provided that in an antidegradation review "any alternatives that would be inconsistent with section 25-8-104 of the Water Quality Control Act shall not be considered available alternatives." If an issue should arise as as to whether the antidegradation review criteria prohibiting material injury are being applied correctly to a specific proposed activity, that issue would be considered during that specific review process, including through consultation with the State Engineer and Water Conservation Board.
The Commission received a letter back from the State Engineer, stating his agreement with the Commission's preliminary assessment. No letter was received from the Water Conservation Board, although the Board had previously indicated its agreement with a similar conclusion when this issue was raised in an earlier rulemaking hearing. Upon consideration of all of the available information, the Commission has determined that the adoption of high quality 2 designations in this proceeding does not cause material injury to water rights.
The other changes considered and adopted are addressed below by segment.
Two principal issues were in controversy for several of the segments addressed in this hearing. The most controversial was whether to apply a high quality 2 designation to certain waters. In several instances, designations proposed by the Water Quality Control Division were opposed on the basis that there was inadequate information to support such a designation. The three most common challenges to the adequacy of the information were:
The commission explicitly considered establishing minimum data requirements when it adopted the current antidegradation regulation, and consciously rejected that option. Rather, the Commission recognized that it would be necessary to rely on best professional judgment to determine what constitutes representative data in a specific situation. These issues are not new, or unique to high quality designations. The Commission has for years been required to make water quality classification and standards decisions in the absence of perfect information. Requiring substantial, recently acquired data for all parameters from multiple locations in each segment before establishing high quality designations would assure that very few waters in Colorado would receive this protection for many years to come. As a policy matter, the Commission has determined that high quality designations may appropriately be established based on a lower threshold of available data than that suggested by several parties to this proceeding.
The Commission also notes that having adequate information upon which to base a high quality designation is not dependent solely on the availability of specific data for a particular segment. Relevant information may include data from downstream segments, comparison of available data with that for similar streams, and information regarding the presence or absence of activities likely to adversely impact the quality of the segment in question.
Where there is a substantial basis for considering a high quality 2 designation, in the face of some residual uncertainty the Commission has chosen to err in the direction of providing the protection. This policy decision is strongly influenced by the ease with which designations can be changed if better data is developed in the future. Unlike classifications, downgrading restrictions do not apply to water quality designations. If new site-specific data is developed that demonstrates that a particular high quality designation is improper, it can and should be removed by the Commission.
With respect to detection limits, the Commission has chosen to continue the same policy that it has followed for over ten years-i.e. to treat data reported as below detection limits as being equivalent to zero. While other methodologies have been proposed and may be defensible, the Commission has determined that this approach is reasonable and appropriate. Requiring rouThe analysis to below table value standard levels for all constituents would substantially increase monitoring costs for the state and the public. Moreover, the Commission believes that the "zero" assumption is fair, so long as it is applied consistently throughout the water quality regulatory system.
Use of zeros in the water quality designation or standard-setting process may marginally err in the direction of increased protection. However, when zeros are used in applying standards to specific dischargers, those dischargers benefit by the assumption that there is more assimilative capacity available in the stream (allowing higher levels of pollutants to be discharged) since the existing pollution is considered to be zero rather than some level between zero and the detection limit.
The second recurring issue addressed for multiple segments in this hearing was whether to establish a recreation class 1 classification wherever a high quality 2 designation is established. The Division proposed this classification change for applicable segments, since the high quality 2 designation indicates that such segments have adequate water quality to support the recreation class 1 use. However, the Commission generally has declined to change the recreation classification from class 2 to class 1 in such circumstances, unless there was also evidence submitted that class 1 uses were present or likely for the waters in question. Unless the use is present or likely, application of use-protection-based water quality standards does not appear appropriate. At the same time, the Commission notes that this approach does not diminish application of antidegradation protection requirements for high quality waters. Where the existing quality is adequate, a high quality 2 designation has been established, requiring antidegradation requirements to be met before any degradation is allowed, even though the recreation classification is class 2.
A related issue is the determination of which uses warrant the class 1 recreation classification. The recreation classification definition in section 3.1.13 (a) (i) of the Basic Standards and Methodologies for Surface Water refers to "activities when the ingestion of small quantities of water is likely to occur," and states that "such waters include but are not limited to those used for swimming." In the past the Commission often has applied the class 1 classification only when swimming occurs, and not where other recreational uses that may result in ingestion of small quantities of water occur. The Commission now believes it is appropriate for the class 1 classification also to be applied for uses such as rafting, kayaking, and water skiing.
The appropriateness of recreation class 1 versus class 2 classifications was debated for several segments in the Lower Colorado Basin. The Commission has received information regarding actual recreational uses. It has also received substantial input regarding the propriety (or lack thereof) of broadening the application of the class 1 recreation classification, based upon an evolving interpretation of the Basic Standards language. After lengthy discussion, the Commission has decided that it is appropriate as a matter of policy in this proceeding to apply the recreation class 1 classification for all uses that involve a significant likelihood of ingesting water, including but not necessarily limited to rafting, kayaking, and water skiing. In particular, the uses at issue for segments in this basin were kayaking and rafting. The Commission has received substantial testimony that kayaking often results in water ingestion. In addition, the testimony presented in this and prior proceedings, as well as the personal experience of individual Commissioners, indicates that rafting-white water or otherwise-also presents a significant potential for water ingestion.
Section 3.1.6 (d) of the Basic Standards and Methodologies for Surface Water requires the Commission to establish classifications to protect all actual uses. Therefore, for waterbodies where rafting and kayaking is an actual use, the recreation class 1 use classification should be applied, since ingestion of water is likely to occur. The Commission sees no reason to distinguish between ingestion that may result from swimming and ingestion that may result from rafting or kayaking. In fact, there has been some testimony indicating that ingestion is more likely to result from the latter activities.
The Commission wishes to emphasize that the action that it is now taking is consistent with the existing definition of class 1 recreation uses. Some of the comments submitted stated or suggested that the action now being taken by the Commission would constitute a "definitional change" that should be addressed only in a review of the Basic Standards and Methodologies for Surface Water. No change in the regulatory definitions of the classifications is being considered or adopted at this time. Rather, the Commission is applying what it believes to be the proper interpretation of the existing definition.
The Commission believes that as a matter of policy it is not necessary or appropriate to wait until the July, 1991 rulemaking hearing regarding the Basic Standards and Methodologies for Surface Water to implement its current interpretation of the class 1 recreation classification. Over the last decade, there have been many instances when arguments and facts presented in basin-specific rulemaking hearings have resulted in an evolving interpretation of the provisions of the Basic Standards and Methodologies for Surface Water. This Commission is not bound by interpretations made by its predecessors in other basin-specific hearings. To the degree that the class 1 recreation classification in the past has not been applied for some existing activities that involve a likelihood of ingesting water, the Commission now believes that such decisions were in error.
This action does not improperly exclude input from entities interested in other river basins. First, the Commission specifically reopened an earlier hearing on the Gunnison Basin and received input from entities not specifically concerned with that basin. This issue has now received extensive consideration in two separate basins. Moreover, the Commission can further modify its policy if in other basin-specific reviews, or in the upcoming review of the Basic Standards and Methodologies, parties that did not participate in this proceeding bring forth new considerations that the Commission believes warrant a modification in the approach to recreation classifications that is now being adopted. The Commission also does not believe that there was any problem with the notice provided for the specific segments at issue in this hearing. Each of the segments for which the recreation classification is being changed from class 2 to class 1 based on rafting or kayaking uses were proposed to be changed to class 1 in the original hearing notice. Although the basis for this proposal evolved during the hearing, any parties potentially concerned with a recreation class 1 classification were on notice that this change would be considered in this hearing.
In applying the interpretation of the existing recreation class 1 definition that has been described, the Commission is also influenced by the fact that the importance of recreational uses of surface waters in Colorado has increased over the last decade. Testimony in this and prior proceedings indicated that uses such as rafting and kayaking have expanded substantially, and it is therefore even more important that adequate water quality protection now be provided.
Some of the testimony submitted addressed the appropriateness of the current fecal coliform standards that are applied in association with recreation classifications. The Commission believes that the appropriateness of the existing standards can and should be addressed, when and if there is new evidence available indicating that the current standards are not appropriate. However, changes in such standards were not at issue in this hearing. The Commission believes that questions regarding the appropriate numerical standards should not interfere with its obligation to establish appropriate classifications to protect existing uses. If members of the public have information indicating that a different indicator parameter should be used, or that different fecal coliform levels are appropriate for the respective recreation classifications, that issue can and should be considered in the upcoming review of the Basic Standards and Methodologies for Surface Water.
Comment also has been submitted to the Commission expressing concern regarding the potential effect of downgrading restrictions, should the Commission now adopt class 1 recreation classifications for certain waters and later change its views regarding the appropriate approach to recreation classifications. The Commission does not believe that this presents a substantial problem. Downgrading is appropriate only when a use is not in place. So long as the class 1 recreation classification is defined as including activities that involve ingestion, applying that classification to waters where uses involving ingestion are present should not present a downgrading issue in the future. If the Commission at some later date should completely revise its approach to, and definition of, recreation classifications, application of the new system would involve a set of "de novo" determinations, and not questions regarding upgrading or downgrading.
The Commission recognizes that the approacin now being adopted may result in increased economic impacts for some dischargers, to meet the class 1 classifications. The evidence that has been submitted to the Commission indicates that in many instances this will not be the case, because state-wide effluent limitations for fecal coliform and chlorine standards to protect aquatic life will often drive the level of disinfection and dechlorination that are required. Moreover, in some circumstances it may be possible for the Division to consider an expanded use of seasonal effluent limitations that take low flow or high flow circumstances into account. However, irrespective of these considerations, a potential increase in treatment requirements for some dischargers cannot eliminate the Commission's obligation to classify state waters to protect actual uses.
Finally, concern was expressed that the approach now taken by the Commission will result in inconsistency regarding recreation classifications for different waters throughout the state. Anytime a policy interpretation changes or evolves in any significant way, the first time the change is applied to specific state waters there will be some inconsistency among individual water bodies, since sitespecific classifications and standards are addressed on a basin-by-basin basis. However, it is the Commission's intention to apply its policy interpretations consistently as individual basins are addressed. This is now the second basin in which this approach has been applied.
Lower Yampa/Green River segments 1, 2, 4, 9, 10, 11, 18, 19, 21
White River segments 3, 4, 6, 7, 8, 10, 23
Lower Colorado River segments 1, 5, 7, 15, 16, 18
Numerical standards for metals for these segments have in most instances been based on table values contained in Table III of the previous Basic Standards and Methodologies for Surface Water. Table III has been substantially revised, effective September 30, 1988. From the information available, it appears that the existing quality of these segments meets or exceeds the quality specified by the revised criteria in Table III, and new acute and chronic table value standards based thereon have therefore been adopted. There are also some of these segments whose previous standards were based in part on ambient quality, since their quality did not meet old table values based on alkalinity ranges. However, these segments generally have much higher hardness than alkalinity, and the new table values (based on hardness-dependent equations) are now appropriate as standards.
Second, review of available data and existing uses indicates that Yampa/Green River segments 1 and 2, White River segment 7, and Lower Colorado segment 1 are appropriate to be upgraded to Recreation class 1 with a corresponding fecal coliform standard of 200 MPN/100 ml.
Third, a High Quality 2 designation has been established for each of these segments. Generally for these segments, the best available information in each case indicates that the existing quality for dissolved oxygen, pH, fecal coliform, cadmium, copper, iron, lead, manganese, mercury, selenium, silver and zinc is better than that specified in Tables I, II, and III of the Basic Standards and Methodologies for Surface Water, for the protection of aquatic life class 1 and recreation class 1 uses. In addition, a portion of Lower Yampa/Green River segment 2 is located within Dinosaur National Monument. The entire segment has been designated High Quality 2 to protect the Monument and for consistency with the upstream and downstream waters. The Commission rejected a proposal to resegment Lower Yampa/Green River segment 2 at the Dinosaur National Monument boundary. An ambient-quality-based iron standard = 1,900 µg/l (Tree) has been established for this segment.
Previous Lower Colorado segments 16a and 16b have been renumbered as segment 15; previous segment 16c is now segment 16.
White River segment 1
Lower Colorado River segment 8
These segments were already described as High Quality class 2, and available information indicates that the parallel new High Quality 2 designation continues to be appropriate for each. All are within wilderness areas. In addition, the following use classifications, and associated table value standards, have been adopted for these segments:
Recreation - Class 2
Cold Water Aquatic Life - Class 1
Water Supply
Agriculture
These classifications and standards are appropriate based on the best available information regarding existing quality and uses. These provisions would apply in the event that degradation is determined to be necessary following an activity-specific antidegradation review.
Lower Yampa/Green River segments 3b, 6, 12, 14, 17, 20 White River segments 5, 9, 13a, 13b, 16a, 22 Lower Colorado River segments 4, lib, lie, 13
These segments all qualify for a use-protected designation based on their present classifications. All are aquatic class 2 streams. Existing standards are recommended because these segments have only a minimal number of standards, with no metal or nutrient standards, except for Lower Colorado segment 4.
The descriptions of Lower Yampa/Green segments 3b and 12a (now 12) have been revised. Segments 3c and 12b have been deleted.
Lower Yampa/Green River segments 3a, 5, 13a, 13b, 16, 22
White River segments 15, 17, 18, 19
Lower Colorado River segments 6, 11d, 17
All of these segments are aquatic life class 2 streams with numeric standards to protect the existing aquatic life. Except as specified below, numerical standards for metals have been based on table values contained in Table III of the previous Basic Standards and Methodologies for Surface Water. Table III has been substantially revised, effective September 30, 1988. From the information available, it appears that the existing quality of these segments meets or exceeds the quality specified by the revised criteria in Table III, and new acute and chronic table value standards based thereon have been adopted. There are also some of these segments whose previous standards were based in part on ambient quality, since their quality did not meet old table values based on alkalinity ranges. However, these segments generally have much higher hardness than alkalinity, and the new table values (based on hardness-dependent equations) are now appropriate as standards.
Ambient quality-based standards:
SegmentConstituents, µg/l
Lower Yampa/Green River 5 Fe (cin) = 1500 µg/l (Tree)
Lower Yampa/Green River 13a Fe (ch) = 1700 µg/l (Tree)
Lower Yampa/Green River 16 Fe (eh) = 2400 ub/l (Tree)
White River 15 Fe (eh) = 11000 µg/l (Tree)
In addition, the aquatic life classification for Lower Yampa/Green River segment 3a is changed from cold water class 2 to warm water class 2.
Lower Yampa segment 7, 15
White segments 11, 14,20
Lower Colorado segments 9, 11a, 11f, 12, 14, 19
These are water bodies whose classifieations are appropriate for High Quality 2 designation (CW1 or WW1 and Ree 1) but had quality not suitable for a water supply classifieation or 85th percentile values of one or two parameters exceeding the criteria for class 1 aquatic life, or may not meet the water quality criteria based on the best available information. Previous segments 14a and 14b have been combined.
Table value standards have been adopted for these segments with the following exceptions:
Segment Constituents, uq/l
White 20 Fe (eh) = 13,500 µg/l (Tree)
Lower Colorado 14 Fe (eh) = 1,250 µg/l (Tree)
White River segment 12, 21
Lower Colorado River segment 2, 3
Review of available data and existing uses indieates that Lower Yampa/Green River segment 2, White River segments 12 and 21, and Lower Colorado segments 2 and 3 are all appropriate to be upgraded to Reereation class 1 with a corresponding fecal coliform standard of 200 MPN/100 ml.
All segments are proposed for the appropriate table value standards except for total recoverable ambient standards for iron of 2,100 µg/l on White, segment 12; 2,300 µg/l on White, segment 20; 2,000 µg/l on Lower Colorado, segment 2; and 2,600 µg/l on Lower Colorado, segment 3.
White River segment 2, 16b
Lower Colorado segment 11c
Segment 2 of the White River is currently designated HQ1. White River segment 16b, and Lower Colorado segment lie have no classifications.
Lower Yampa/Green River segment 8
Lower Colorado segment 10
Each of these segments were reservoirs that are no longer in operation.
Parties to the September, 1990 Hearing
5 CCR 1002-37.11