5 Colo. Code Regs. § 1002-37.10

Current through Register Vol. 47, No. 20, October 25, 2024
Section 5 CCR 1002-37.10 - STATEMENT OF BASIS AND PURPOSE
I.Introduction

These stream classifications and water quality standards for State Waters of the Colorado River Basin below Glenwood Springs; the Yampa River Basin below Elkhead Creek; the Green River; and the entire White River drainage including all tributaries and standing bodies of water associated with those rivers in all of Moffat, Rio Blanco, Garfield, and portions of Mesa and Routt Counties implement requirements of the Colorado Water Quality Control Act C.R.S. 1973, 25-8-101et seq. (Cum. Supp. 1981). For the sake of brevity this regulation shall be referred to as "The Lower Colorado". Regulations Establishing Basic Standards and an Antidegradation Standard and Establishing a System for Classifying State Waters, for Assigning Standards, and for Granting Temporary Modifications (the "Basic Regulations")

The Basic Regulations establish a system for the classification of State Waters according to the beneficial uses for which they are suitable or are to become suitable, and for assigning specific numerical water quality standards according to such classifications. Because these stream classifications and standards implement the Basic Regulations, the statement of basis and purpose (Section 3.1.16) of those regulations must be referred to for a complete understanding of the basis and purpose of the regulations adopted herein. Therefore, Section 3.1.16 of the Basic Regulations is incorporated by reference. The focus of this statement of basis and purpose is on the scientific and technological rationale for the specific classifications and standards in the Lower Colorado.

Public participation was a significant factor in the development of these regulations. A lengthy record was built through a public hearing held October 11-13, 1982. A total of 25 entities requested and were granted party status by the Commission in accordance with C.R.S. 1973, 24-4-101et seq. (Cum. Supp. 1980). The record established in the hearing forms the basis for the classifications and standards adopted.

II.General Considerations
1. The Commission determined that consistant with the policy of January 5, 1981, entitled: "A Policy of Water Quality and Quantity Issues", and section 25-8-503(5) C.R.S. 1973, these water quality classifications and standards adopted for the Lower Colorado River Basin are not intended to be control regulations nor intended to apply to dams, diversion, carriage, and exchange of water from or into streams, lakes, reservoirs, or conveyance structures, or storage of water in or the release of water from lakes, reservoirs, or conveyance structures, in the exercise of water rights.
III.Definition of Stream Segments
1. For purposes of adopting classifications and water quality standards, the streams and water bodies are identified according to river basin and specific water segments.
2. Within each river basin, specific water segments are defined, for which use classifications and numeric water quality standards, if appropriate, are adopted. These segments may constitute a specified stretch of a river mainstem, a specific tributary, a specific lake or reservoir, or a generally defined grouping of waters within the basin (e.g., a specific mainstem segment and all tributaries flowing into that mianstem segment).
3. Segments are generally defined according to the points at which the use, water quality, or other stream characteristics change significantly enough to require a change in use classification and/or water quality standards. In many cases, such transition points can be specifically identified from available data. In other cases the delineation of segments is based upon best judgments of the points where instream changes in uses, water quality, or other stream characteristics occur.
IV.Use Classifications and Standards - Generally
1. Initially, recommendations for stream segmentation and use classifications are a result of input from 208 plans, water quality data and reports, the Division of Wildlife, and personal knowledge. After a basic outline of stream segments and use classifications was prepared, water quality data from a variety of sources was compared against the "table value" for the proposed use. "Table value" refers to the four tables attached to the "Basic Regulations". In general, if the mean plus one standard deviation (x + s) of the available data for the segment indicated that a particular parameter did not exceed the "table value" for that recommended use, the "table value" was listed as the recommended standard for the parameter. If the x + s computation indicated that the instream concentrations of the parameter exceeded the "table value" and yet the use to be protected by that parameter was in place, then the x + s value was recommended as the standard for that parameter.

Conversely, if the ambient quality (x + s) for a certain parameter exceeded the "table value" for the protection of a use, and there is information that the proposed use is not in place, the use classification was changed or temporary modifications to the parameters were established. Ambient quality is generally defined as the quality attributable to natural conditions and/or uncontrollable non-point sources.

2. The use classifications have been established in accordance with the provisions of Section 203 of the Water Quality Control Act and Section 3.1.6 and 3.1.13 of the Basic Regulations.
3. In most cases upstream segments of a stream are generally the same as, or higher in classification, than downstream segments in order to protect downstream uses. In a few cases, tributaries are classified at lower classifications than mainstems where flow from tributaries does not threaten the quality of mainstem waters where the evidence indicates that lower classification for the tributaries is appropriate.
4. The Commission has determined that it has the authority to assign the classification "High Quality Waters - Class 1" and "High Quality Waters - Class 2" where the evidence indicates that the requirements of Sections 3.1.13 of the basic regulations are met. The appropriateness of this classification has been determined on a case-by-case basis. Streams have in some cases been classified "High Quality - Class 2" for one or more of the following reasons:
(a) to facilitate the enjoyment and use of the scenic and natural resources of the State in accordance with the Legislative Declaration of the Colorado Water Quality Control Act (25-8-102(1) C.R.S. 1973.
(b) to provide a high degree of protection deserving of wilderness areas which are a resource providing a unique experience.
(c) they contain threatened species or apply to wild and scenic river study areas or wilderness areas.
(d) the concern of the USPS that High Quality 2 classification will unduly burden their management of multiple use areas is not well founded. This is because those historical activities on Forest Service land, i.e. grazing, mineral exploration, trail and road maintenance, are considered as a part of existing ambient water quality conditions and are non-point sources which are presently not subject to any Water Quality Control Commission regulations.
(e) a question exists as to winetlner existing diversion structures can be maintained consistent witin a "Higin Quality - Class 1" designation. Because of the questions regarding authority to regulate diversions, the Class 1 designation was deemed potentially too rigid. The Commission recognizes its authority to upgrade any segments needing higher levels of protection if and when it is appropriate to do so.

Where High Quality 1 or 2 may not have been proposed, even if the waters meet the criteria in 3.1.13(1)(e) of the Basic Regulation, it was deemed important in those cases to assign specific water quality standards to protect the highest specific use classifications, and only specific use classifications provide the mechanism for assigning such standards. The use of high quality is optional at the discretion of the Commission.

5. In accordance with 25-8-104, C.R.S. 1973, the Commission intends that no provision of this regulation shall be interpreted so as to supercede, abrogate, or impair rights to divert water and apply water to beneficial uses.
6.Recreation - Class 1 and Class 2

In addition to the significant distinction between Recreation - Class 1 and Recreation - Class 2 as defined in Section 3.1.13 of the Basic Regulations, the difference between the two classifications in terms of water quality standards is the fecal coliform parameter. Recreation -Class 1 generally has a standard of 200 fecal coliform per 100 ml; Recreation - Class 2 generally has a standard of 2000 fecal coliform per 100 ml.

In accordance with the Colorado Water Quality Control Act, the Commission has decided to classify as Recreation - Class 2 those stream segments where primary contact recreation does not exist and cannot be reasonably expected to exist in the future, regardless of water quality. The Commission has decided to classify as Recreation - Class 1 only those stream segments where primary contact recreation actually exists, or could reasonably be expected to occur. The reasons for the application of Recreation Class 2 are as follows:

(a) The mountain streams in this region are generally unsuitable for primary contact recreation because of low water temperature and low stream flows.
(b) Fecal coliform is an indicator organism. Its presence does not always indicate the presence of pathogens. This depends on the source of the fecal coliform. If the source is agricultural runoff as opposed to human sewage, there may be no health hazard and therefore no significant need to reduce the presence of fecal coliform to the 200 per 100 ml. level. Also, control of nonpoint sources is very difficult.
(c) Treating sewage to meet the 200 per 100 ml. level generally means the treatment plant must heavily chlorinate its effluent to meet the limitation. The presence of chlorine in the effluent can be significantly detrimental to aquatic life. Post-treatment of effluent to meet the residual chlorine standard is expensive and often results in the addition of more chemicals which have a negative effect on water quality and can be detrimental to aquatic life. Therefore, reducing the need for chlorine is beneficial to aquatic life.
(d) Even where a treatment plant in this region might treat its effluent to attain the standard of 200 per 100 ml., agricultural runoff and irrigation return flows below the plant may result in the rapid increase of fecal coliform levels. Therefore, the benefits of further treatment are questionable.
(e) The fecal coliform standard of 2000 per 100 ml. has been established to provide general public health protection. There is no significant impact on domestic drinking water treatment plants because they provide complete disinfection. The standard of 200 per 100 ml. is not intended to protect the water supply classification.

Recreation on private lands will be dealt with by the Commission on a segment by segment basis.

7.Water Supply Classification

The Commission finds that Colorado is a water short state and that it is experiencing considerable growth which places additional burdens on already scarce water supplies. These considerations mitigate in favor of a conservative approach to protecting future water supplies. Where existing water quality is adequate to protect this use, and in the absence of dischargers to these segments or testimony in opposition to such classification, the water supply use has been assigned because it is reasonable to expect that it may exist in the future in such cases. For stream segments that flow through, or in the vicinity of, municipalities, this conclusion is further justified, since there is a reasonable probability that the use exists or will exist. Where the water supply classification has been opposed, the Commission has evaluated the evidence on a site specific basis, and in many cases the classification has been removed.

V.Water Quality Standards - Generally
1. The water quality standards for classified stream segments are defined as numeric values for specific water quality parameters. These numeric standards are adopted as the limits for chemical constituents and other parameters necessary to protect adequately the classified uses in all stream segments.
2. Not all of the parameters listed in the "Tables" appended to the Basic Regulations are assigned as water quality standards. This complies with Section 3.1.7(c) of the Basic Regulations.

Numeric standards have been assigned for the full range of parameters to a number of segments where little or no data existed specific to the segment. In these cases, there was reason to believe that the classified uses were in place or could be reasonably expected, and that the existing water quality was as good as or better than the numeric standards assigned.

3. A numeric standard for the temperature parameter has been adopted as a basic standard applicable to all waters of the region in the same manner as the basic standards in Section 3.1.11 of the Basic Regulations.

The standard of a 3°C temperature increase above ambient water temperature as defined is generally valid based on the data regarding that temperature necessary to support an "Aquatic Life - Class 1" fishery. The standard takes into account daily and seasonal fluctuations; however, it is also recognized that the 3°C limitation as defined is only appropriate as a guideline and cannot be rigidly applied if the intention is to protect aquatic life. In winter, for example, warm water discharges may be beneficial to aquatic life. It is the intention of the Commission in adopting the standard to prevent radical temperature changes in short periods of time which are detrimental to aquatic life.

4. Numeric standards for seventeen organic parameters have been adopted as basic standards applicable to all waters of the region in the same manner as the basic standards in Section 3.1.11 of the Basic Regulations. These standards are essential to a program designed to protect the waters of the State regardless of specific use classifications because they describe the fundamental conditions that all waters must meet to be suitable for any use.

It is the decision of the Commission to adopt these standards as basic standards because the presence of the organic parameters is not generally suspected. Also, the values assigned for these standards are not detectable using rouThe methodology and there is some concern regarding the potential for monitoring requirements if the standards are placed on specific streams. This concern should be alleviated by Section 3.1.14 of the Basic Regulations but there is uncertainty regarding the interpretation of those numbers by other entities. Regardless of these concerns, because these constituents are highly toxic, there is a need for regulating their presence in State waters. Because the Commission has determined that they have uniform applicability here, their inclusion as basic standards for the region accomplishes this purpose.

5. In some cases, the numeric water quality standards are taken from the "Tables" appended to the Basic Regulations. These table values are used where actual ambient water quality data in a segment indicates that the existing quality is substantially equivalent to, or better than, the corresponding table values. This has been done because the table values are adequate to protect the classified uses.

Consistent with the Basic Regulations, the Commission has not assumed that the table values have presumptive validity or applicability. This accounts for the extensive data in the record on ambient water quality. However, the Commission has found that the table values are generally sufficient to protect the use classifications. Therefore, they have been applied in the situations outlined in the proceeding paragraph as well as in those cases where there is insufficient data in the record to justify the establishment of different standards. The documentary evidence forming the basis for the table values is included in the record.

6. Cases in which water quality standards reflect these instream values usually involve the metal parameters. On many stream segments elevated levels of metals are present due to natural or unknown causes, as well as mine seepage from inactive or abandoned mines. These sources are difficult to identify and impractical or impossible to control. The classified aquatic life uses may be impacted and/or may have adjusted to the condition. In either case, the water quality standards are deemed sufficient to protect the uses that are present.
7. Some segments encompass great distances and include a large number of tributaries. Some tributaries are perennial streams which legitimately are aquatic uses. However, within the segment are dry gulches which would not be classified as aquatic life. Subsequent reviews should seek to separate the aquatic classified streams from the non-aquatic dry gulches. In some of those segments containing dry gulches, no aquatic numeric standards were adopted.

Criteria for distinguishing between dry gulches which were classified as aquatic and those which were non-aquatic were as follows: If the aquatic life use exists during times when flow occurs, then the aquatic life use applies, but where no data was presented concerning conditions during flows, then vegetation, slope of dry stream bed, nature of hydrologic conditions (i.e., predominance of sudden precipitation events), condition of the streambed, and proximity to perennial streams were considered in reaching a conclusion.

In those cases where there was no data for a particular segment, or where the data consists of only a few samples for a limited range of parameters, "table values" were generally recommended. Data at the nearest downstream point was used to support this conclusion. In some cases, where the limited data indicated a problem existed, additional data were collected to expand the data base. Additionally, where there may not be existing data on present stream quality, the Commission anticipates that if necessary, additional data will be collected prior to a hearing required by C.R.S. 1973, 25-8-204(3), as amended.

There was very little data available particularly for metal parameters for some portions of the following segments: 1/4, 2/9, 3/11, 3/14, 4/15, 4/17, 4/20, 5/21, 5/22, 6/3, 6/5, 6/6, 7/8, 7/9, 7/10, 7/11,9/19, 10/22, 10/23, 11/5, 11/6, 14/14, 14/17, & 15/18.

8. Where endangered species spawning and young of the year rearing were identified, the Commission considered using The Higin Quality designation. However, this designation was not adopted at tinis time since, in the case of the Colorado Squawfish, the Humpbacked Chub, and the Razorback Sucker maintaining existing quality has not been established to date as necessary to maintaining the endangered species. The aquatic classification establishes existing parameter conditions and should provide sufficient protection of the aquatic life use so as to maintain these species
9. In most cases in establishing standards based on instream ambient water quality, a calculation is made based upon the mean (average) plus one standard deviation (x + s) for all sampling points on a particular stream segment. Since a standard deviation is not added to the water quality standard for purposes of determining the compliance with the standard, this is a fair method as applied to discharges.

Levels that were determined to be below the detectable limits of the sampling methodology employed were averaged in as zero rather that at the detectable limit. This moves the mean down but since zero is also used when calculating wasteload allocations, this method is not unfair to dischargers.

Metals present in water samples may be tied up in suspended solids when the water is present in the stream. In this form they are not "available" to fish and may not be detrimental to aquatic life. Because the data of record does not distinguish as to availability, some deviation from table values, and the use of x + s, is further justified because it is unlikely that the total value in all samples analyzed is in available form.

A number of different statistical methodologies could have been used where ambient water quality data dictates the standards. All of them have both advantages and disadvantages. It is recognized that the x + s methodology also has weaknesses, in that the standard may not reflect natural conditions in a stream 100 per cent of the time, even though the use of x + s already allows for some seasonal variability. However, the use of this methodology is justified since it provides a meaningful index of stream quality for setting stream standards.

Since the X + s methodology is an index of existing conditions and is not a classical statistical description, use of a methodology which eliminates outlyers, i.e. unusually high or low data which may be in error, is acceptable in approximating an average condition. The practice of eliminating only extremely high recorded data points and not low recorded values may result in erring on the side of safety. High recorded values may be due to sampling, laboratory, or recording error. To a limited degree the high values may be due to seasonal variation in the data base.

Several parties questioned whether Chauvenet's criterion was being used properly and questioned the appropriateness of not including outliers in the mean plus 1 standard deviation calculation. The Commission finds that both practices are appropriate in their application.

Chauvenet's criterion is not being used to reject data. Chauvenet's criterion is being used to identify suspicious data points which need to be evaluated further to determine if the data represents typical stream conditions. Data identified by Chauvenet's criterion are only rejected as outliers if it can be shown that:

1) The sample contained high suspended solids or turbidity, indicating a typical spring run-off condition;
2) The sample was taken at a time when a radical change in stream flow was present, indicating an atypical storm event; or,
3) The sample resulted in an unexplained value radically beyond two standard deviations and was an isolated data point, suggesting a sampling, laboratory, or reporting error.

Data not included in the mean plus 1 standard deviation calculation are not rejected from the data base. Should future testing indicate that these high values are typical results for a particular stream segment, then these data points will be included in the ambient level calculation.

It should be noted that setting stream standards (above table values) involves a multifaceted methodology. Each part of this methodology is founded on certain assumptions: Some of these are conservative in nature, some are not. For example a conservative assumption is the rejection of outliers, an unconservative assumption is the x + s calculation which allows for the standard to be exceeded about 15% of the time. This methodology as a whole is needed to protect the beneficial uses of Colorado's water. To relax only one aspect of this methodology without adjusting the counterbalancing assumptions could seriously threaten the beneficial uses of State Waters. No testimony was presented to the Commission which evaluated how the inclusion of outliers would impact aquatic life if the remainder of the methodology remained unchanged.

The Commission recognizes that the x + s methodology departs from formal statistical techniques. However, since this methodology is intended only to produce an index of existing stream values which are present 85% of the time, a departure from formal statistical techniques is acceptable. Again, the methodology as a whole represents a balance of assumptions which cannot be forced into a formal statistical approach because of the complexities of the instream chemicals values and biological response relationships.

It was suggested that the stream data be "Normalized" prior to the application of Chauvenet's criterion. The Commission finds that this approach is infeasible for two reasons:

1) Much of the water quality data is not distributed in a "Log-Normal" fashion which precludes it from being normalized; and,
2) The normalization process cannot legitimately be applied to a data set that contains zeros, as water quality data does.

Finally, the fairness and consistency of the use of any methodology in setting standards must recognize the manner in which the standards are implemented and enforced. It is essential that there be consistency between standard setting and the manner in which attainment or non-attainment of the standards is established based on future stream monitoring data. In addition the Division must take this methodology into account in writing and enforcing discharge permits.

10. No water quality standards are set below detectable limits for any parameter, although certain parameters may not be detectable at the limit of the standards using rouThe methodology. However, it must be noted that stream monitoring, as opposed to effluent monitoring, is generally not the responsibility of the dischargers but of the State. Furthermore, the purpose of the standards is to protect the classified uses and some inconvenience and expense as to monitoring is therefore justifiable.

Section 3.1.15 of the Basic Regulations states that "dischargers will not be required to regularly monitor for any parameters that are not identified by the Division as being of concern". Generally, there is no requirement for monitoring unless a parameter is in the effluent guidelines for the relevant industry, or is deemed to be a problem as to a specific discharge.

11. The dissolved oxygen standard is intended to apply to the epilimnion and metalimnion strata of lakes and reservoirs. Respiration by aerobic micro-organisms, as organic matter is consumed, is the primary cause of a natural decrease in dissolved oxygen and anaerobic conditions in the hypolimnion. Therefore, this stratum is exempt from the dissolved oxygen standard.
12. Where numeric standards are established based on historic instream water quality data at the level of X + s, it is recognized by the Commission that measured instream parameter levels might exceed the standard approximately 15 percent of the time.
13. It is the Commission's intention that the Division implement and enforce all water quality standards consistent with the manner in which they have been established.
14.Hardness/Alkalinity

Where hardness and alkalinity numbers differed, the Commission elected to use alkalinity as the controlling parameter, in order to be consistent with other river basins and because testimony form the Division staff indicated that in most cases alkalinity has a greater effect on toxic form of metals than does hardness.

VI.Water Quality Standards for Unionized Ammonia

The Commission retains the use of unionized ammonia as a parameter rather than total ammonia because unionized ammonia is the toxic portion. Furthermore, the relationship of total ammonia as a function of temperature and pH is recognized.

VII.Water Quality Standards for Uranium

Given the threat that radioactivity from uranium may pose to human health, it is advisable to limit uranium concentrations in streams to the maximum extent practicable. For segments assigned a water supply classification the Commission has adopted a standard of 40 pCi/l or natural background where higher, for the following reasons:

1. 40 pCi/l generally reflects background concentrations of uranium that may be found in streams in Colorado and therefore this amount approximates rouThe human exposure.
2. The statistical risk of human health hazards is small at 40 pCi/l.
3. 40 pCi/l is an interim level, established now pending the outcome of further studies currently underway.

Data introduced in the record on the establishment of a standard of 10 pCi/l were rejected. The Commission felt that it was more appropriate to reexamine the uranium standard on a Statewide basis with more public participation at a future date.

VIII.Water Quality Standards for Cyanide

The Commission acknowledges that total cyanide is to be used in State Discharge Permits until a method is authorized by EPA for measuring free cyanide, even though free cyanide is the parameter of concern.

IX.Water Quality Standards for Metals

Moreover, the Commission recognizes that the overwhelming majority of available water quality data was obtained using total digestion and total recoverable laboratory analytical techniques.

In deciding to retain the total recoverable laboratory analytical technique as appropriate for the purpose of setting stream standards, the Commission noted that the standards setting process consists of many elements that result in a balanced water quality control program. These various elements include laboratory methodologies, stream classifications, statistical analysis of data, mean plus standard deviation, data screening including Chauvenet's criterion, discharge permit monitoring procedures and many others. Changing any of these elements would require total reevaluation of the entire standards setting process and water quality management procedures requiring a much broader base of evidence than is available in the Lower Colorado hearing record.

X.Linkage of classifications and Standards

The Commission Inolds that the classifications which it adopts and the standards it assigns to them are linked. Disapproval by EPA of the standards may require reexamination by the Commission of the appropriateness of its original classification. The reason for the linkage is that the Commission recognizes that there is a wide variability in the types of aquatic life in Colorado streams which require different levels of protection. Therefore, the numbers were chosen in some cases on a site specific basis to protect the species existing in that segment. If any reclassification is deemed a downgrading, then it will be based upon the grounds that the original classification was in error.

Xi.Economic Reasonableness

The Commission finds that these use classifications and water quality standards are economically reasonable. The Commission solicited and considered evidence of the economic impacts of these regulations. This evaluation necessarily involved a case-by-case consideration of such impacts, and reference is made to the fiscal impact statement for this analysis. Generally, a judgment was made as to whether the benefits in terms of improving water quality justified the costs of increased treatment. In the absence of evidence on economic impacts for a specific segment, the Commission concluded that the regulations impose no unreasonable economic burden.

Xii.Classifications and Standards - Special Cases
1.Page 1, Segment 1

Through its testimony, the City of Craig expressed concern that it would be required to provide advanced waste treatment (AWT) to meet proposed standards for this segment. The Commission found that there was dilution flow sufficient to preclude an AWT requirement at this time.

2.Page 1, Segments 2

The Commission recognized that that portion of the segment which is in the Dinosaur National Monument has been proposed for Federal Wild and Scenic designation and that the segment provides a spawning habitat for the Colorado Squawfish, an endangered species. Thus, the Commission chose not to classify the segment as high quality feeling that the proposed classifications adequately protected the existing uses.

3.Page 1, Segment 3(a), 3(b), and 3(c) (proposed as page 1, segment 3)

The issue generated by the testimony was the presence of aquatic life and the habitat necessary for fish spawning. It was testified that spawning did not occur in segment 3(a). Portions of these segments were gulches or dry washes not suitable for use by aquatic life. In the physical and biological evaluation of tributaries the Commission found steep sage brush covered slopes. The drainage ways are generally dry and covered by stands of sagebrush and various grass species. The Commission differentiated those gulches which are dry from those which should be classified aquatic due to flow. The criteria of frequency and duration of flow were used by the Commission in determining at what point limited aquatic life existed for which a classification should be assigned. Resegmentation enabled the Commission to be responsive to the testimony of Axial Basin Ranch, Colowyo Coal Company, Trapper Mining, Inc., and Utah International, Inc., in classifying portions of this segment for aquatic life while not so classifying other portions.

4.Page 2, Segment 7

The W. R. Grace Company, a partner in the Colowyo Company urged in its testimony that the segment not be classified for water supply because of the impact such classification could have on future coal mining. It was testified that the City of Craig was a growth area but that no water supply use was in place nor did the Division have any record of conditional water decrees. Based on this evidence, the Commission did not classify this segment for water supply use and modified the numeric standards accordingly.

5.Page 3. Segment 12(a) and 12(b) (proposed as page 2. segment 12)

The Commission was pursuaded by the testimony of the Trapper Mining Company to segment out Ute and Castor Gulches as 12(b) because they are dry steep drainages of the Williams Fork ridge. They were classified only for agricultural use. Segment 12(a) remains as proposed.

6.Page 3. Segment 13(a) and 13(b) (proposed as page 3, segment 13)

This segment was resegmented at the Hamilton Bridge on County Highway 13/789 because it provided a landmark on the segment where temperature changes could occur in a transitional reach. This conclusion was based on observations of cold water fish species above the bridge and warm water species below the bridge. Resegmentation enabled the Commission to assign a cold water aquatic life classification above the bridge and a warm water aquatic life classification below the bridge.

7.Page 6, Segment 2

The Commission classified this segment high quality class 1 to provide protection for the Colorado River Cutthroat Trout, a Colorado endangered species. Testimony indicated the segment is a critical spawning area and a resource area for recovery of eggs.

8.Page 7, Segment 7

The Commission found from evidence that though the issue of a seasonal standard was raised that two data outlyers were insufficient to warrant such a qualifier. Bar 70 Enterprises Inc., which did not testify but did submit evidence and a summation indicated it intended to use the segment as a water supply source. Their concern was whether the .02 mg/l unionized ammonia would create a problem. The Commission determined that it would not if there was no significant change in the water flow in the stream. There was no evidence of water flow change. It appeared to the Commission that for both the Town of Meeker and Bar 70 Enterprises Inc., there does not appear to be any fiscal impact due to the aquatic life class 1 classification.

9.Page 7, Segment 12

For several parameters collected September 11, 1975, the concentrations were deemed to be unusually high and were eliminated. It was felt by the Commission that a recording error had occured.

10.Page 8, Segment 13(a) and 13(b) (proposed as page 7, segment 13)

Yellow and Spring Creeks and their tributaries were segmented out as 13(b) due to their limited flow and testimony that they contained no aquatic life. Neither aquatic life nor recreation classifications were assigned to 13(b).

11.Page 8. segment 14(a) and 14(b) (proposed as page 7, segment 14)

There is no hardness or alkalinity data available for segment 14(a). The nearest station is in the next segment downstream where alkalinity is recorded in the range of 300 to 400. 400 plus is the combined alkalinity value from all stations in 14(b). Resegmentation was at State Highway 13 separating segment 14(a) from 14(b). The Emily Oldland diversion separating segment 14(b) from segment 15 is a barrier to fish migration.

12.Page 8, Segment 15

It was testified that Cathedral Bluffs Oil Shale Company was generally not releasing their discharge to the stream. Depending of the time of year they were either discharging down No-Name Gulch; sprinkling on the tract for evaporation; or using underground injection. This practice was followed because the Company felt that it must take these actions to meet its discharge permit limitations. The Commission found from the testimony that protection was being given aquatic life at the expense of agricultural use. It was testified that the fish in the segment were escapees from agricultural ponds and were not a reproducing population that was fished. Because of its greater economic value, the Commission found agriculture to be a higher and more beneficial use in this segment than was aquatic life. Therefore, the Commission modified the numeric standards for ammonia, cadmium, boron, selenium and alkalinity to levels appropriate for the agricultural use in place. The balance of the numbers were set consistant with the 400 alkalinity level.

13.Pages 8 & 9, Segment 16(a) and 16(b)

Segment 16(b) is composed of tributary streams not previously classified. The Commission recognized these segments in the classification system but chose to identify them as not classified. The Commission found that in the light of the direction it received in Senate Bill 10 there is no requirement that it classify every creek bed. In this instance the Commission has examined these tributaries, listed them in the segment description, and said they were not classified. This exempts them from the broad blanket of tributaries. The Commission found no fish in the segment and an extensive algal community present prior to the industrial use. The Commission determined not to classify these tributaries to avoid creating an unreasonable adverse economic impact on Cathedral Bluffs Shale Oil Company.

Because of the industrial nature of the lease tract none of the uses within the table of classifications are likely to occur nor are they economically justified. The Commission found these tributaries to be basically dry gulches.

14.Pages 12 & 13, Segment 11(a) through 11(f) (proposed as page 10, segment 11)

The upper portions of Parachute Creek were resegmented 11 (a) through 11 (f) in order to address specific issues as follows: 11 (a) contained portions of streams about which the testimony supported the assigned classifications; 11 (b) the Division supported and evidence substantiated that these streams were intermittent. Evidence further substantiated an agricultural use in these segments or at least immediately downstream; 11 (c) evidence presented did not support any of the beneficial use classifications listed in the basic regulations as being appropriate for this segment because the Exxon industrial use of the property precludes such uses. No fishery exists or is likely to exist. Algal life existed but the industrial use on the property precludes any aquatic life classification; 11 (d) recreation, class 2, was proposed for this segment but was not assigned by the Commission because evidence presented indicated that the major portion of this segment is on private property and public access is prohibited. Water supply was proposed but not assigned because testimony indicated no water supply uses exist in this segment nor could reasonably be expected to occur. The Division recommended and testimony supported the assignment of agriculture and cold water aquatic life, class 1; 11 (e) when water is there, aquatic use is there. The stream bed supports aquatic use during spring runoff in the April, May, and June period. Because of aquatic use above and below this segment the Commission expects movement offish into this stream segment. Because of potential economic impact upon Union Oil Company's shale disposal waste pile, no numeric standards other than minimum standards for this segment were adopted. Discharge may not in fact occur in this segment. The Mined Land Reclamation Board could approve structures over or beside the streambed to protect the stream flow sufficient to protect downstream segments aquatic life, class 1 use; should this segment be used for waste disposal such that the aquatic use no longer occurs even during spring runoff, then a redesignation will be appropriate.

No recreation use was adopted because no access has been historically allowed. 11 (f) testimony indicated perennial flow and aquatic life including trout present within this segment.

15.Page 13, Segment 13

Clear Creek was moved to this segment from segment 15. There was testimony that recreation classification not be assigned. However, the Commission determined from other testimony that the extent of public access to this segment warranted a recreation classification.

16.Page 14, Segment 16(a), 16(b) and 16(c) (proposed as page 11, segment 16)

This resegmentation was to accomodate alkalinity differences between these reaches of the stream.

FISCAL IMPACT STATEMENT

Stream Classifications and Water Quality Standards for State Waters of the Lower Colorado Basin below Glenwood Springs; the Yampa River Basin below Elkhead Creek; the Green river; and the entire White River drainage including all tributaries and standing bodies of water associated with those rivers in all of Moffat, Rio Blanco, Garfield, and portions of Mesa and Routt Counties.

I.Introduction

The Water Quality Control Commission is charged with he responsibility to conserve, protect, and improve the quality of state waters pursuant to C.R.S. 1973, 25-8-101et seq.

The Commission is further empowered and directed to classify waters of the State and to promulgate water quality standards for any measurable characteristic of the water in order to protect both the uses in place and those that can be reasonably expected in the future. (25-8-203 and 25-8-204) The above-titled document assigns use classifications and standards for the state waters in the listed areas in accordance with the "basic regulations" adopted May 22, 1979.

The measurable fiscal impacts which may be caused by these regulations are as follows:

* Cost of construction due to requirements for increased levels of treatment by municipal waste treatment facilities;

* Cost of construction due to requirements for increased levels of treatment by industrial/commercial waste treatment facilities;

* Cost of Operation and Maintenance associated with increased levels of treatment required of municipalities;

* Cost of Operation and Maintenance associated with increased levels of treatment required of industrial and commercial dischargers;

* Cost of instream monitoring and laboratory analysis for new parameters added by the standards.

Dischargers will not be required by the adoption of these regulations to do stream monitoring. The state, federal and local agencies now doing instream monitoring will have some increased cost; however, any additional frequency should be done to improve state surveillance and would be needed regardless of standard changes.

The stream classifications and standards adopted by the Commission will protect the water uses primarily through control of point source pollution. Nonpoint source pollution will be controlled primarily through management practices which are in existence or which will be implemented in the future. Future management practices need careful consideration and may be the result of 208 area-wide wastewater management plans developed by regional planning agencies and being updated annually. These plans involve local governments with general assistance from state government. Some of the possible nonpoint source pollution may be controlled through "Control Regulations" yet to be promulgated by the Commission. These types of controls could involve runoff from construction, mining activities, and urban areas. It is not certain what controls are needed at this time and there is no way that possible costs can be identified at this time.

Persons who benefit from standards which will protect existing and future anticipated uses can be identified as all persons benefiting from recreation, municipal water supply, and agriculture. These benefits are directly economic for agriculture, industry, and municipalities whose health benefit costs are reduced by having clean water, and are both economic and nonquantifiable for some uses such as fishing, recreation, and the aesthetic value of clean waters. Furthermore, benefits will result from human health protection and lack of debilitating disease. Figures have been developed for a recreation/fishing day which can be applied to that aspect of a water use; however, figures which have been developed for total recreation/fishing day uses have been developed statewide and could not be applied region-by-region or stream-by-stream.

The uses of water in this region are adequately protected by these standards. Most municipal treatment facilities and industrial facilities are currently adequate, or are already being upgraded, in order to meet previous requirements. Any additional facilities or expansions in this region will generally be caused by increased capacity required because of population growths or industrial enlargement. Industries are required by federal statute to meet effluent limitations described as "Best Available Technology Economically Achievable" (BATEA) by 1983 or 1984. For most major industries in this region, the water quality standards should not require treatment beyond these limitations.

The fiscal impact of any regulatory decision must take into account only the incremental costs explicitly associated with the regulations as finally promulgated. Costs and expenditures associated with the regulations as finally promulgated. Costs and expenditures associated with the status quo, regulations of other regulatory agencies, or regulations already in effect should not be included in an assessment of the fiscal impact of the Lower Colorado Basin classifications.

In addition, a distinction must be made between actual expenditures or dislocations that will be immediately or unavoidably necessary upon promulgation of these classifications and standards, and those costs which are speculative in nature. In keeping with concepts of "Expected Value", it is proper for the Commission to place more emphasis on definite impacts.

With the passage in 1981 of Senate Bill 10, amending the Colorado Water Quality Control Act, it became incumbent upon the Water Quality Control Commission to consider the economic impact of their decisions with more emphasis placed upon the concept of the "Economic Reasonableness". Charged with such a mandate, the Commission was quite sensitive to the objective of minimizing the socio-economic "price" of clean water while adhering to the antidegradation policy that water quality be preserved and protected in all cases, and improved where feasible.

The analysis and data which follows is derived primarily from testimony and exhibits offered by interested parties during the course of the rulemaking hearings. This was supplemented by staff estimates of potential impacts upon other major entities who and private sectors. Except for instances where explicit testimony was given by interested parties at the rulemaking hearing, no attempt has been made to identify future development costs as this type of data is not readily available and estimation techniques are dependent upon many highly subjective assumptions. Finally, to fully illustrate the degree to which costs were minimized where possible, two tables for each sector are presented. The first table itemizes the impacts of the classifications as proposed while the second table depicts the impacts of the classifications as finalized.

II.FISCAL IMPACT: PUBLIC SECTOR

The primary fiscal impact to the public sector in this basin involves the potential domestic wastewater treatment costs associated with the stream classifications and water quality standards. Other costs, such as tax and employment base impacts due to forgone industrial development opportunities or mitigated growth potentials, can be theoretcially postulated but are difficult to quantify. Generally, it is recognized that higher tap fees, service charges or property taxes associated with increased treatment costs can potentially affect industrial siting decisions. However, this is not as significant as increased levels of treatment that may be required of industries if they are dischargers. While the Commission acknowledges the existence of such potentials, the lack of firm evidence and actual tax base impact estimates make deliberative assessment impractical.

In this basin the Commission acknowledged eleven municipalities that could potentially incur an economic impact: The Towns of Craig, Grand Junction, Monument Meadows, Fruita, DeBeque; and the following special districts: Ute Water Conservancy District, Clifton Sanitation District, Collbran Wastewater, Panorama Improvement District, Meeker Water and Sanitation District, Bar 70 Proposed Sanitation District. In each case the ammonia standard was the factor of concern. It is the Commission's finding that for each of these dischargers, the flow of the receiving waters is sufficient to provide adequate protection from advanced wastewater treatment (AWT) requirements. Although future growth in this region may require AWT considerations, there was no specific evidence to suggest when this could be expected and what final impact would result. The Commission finds that sufficient protection exists in sections 25-8-204(3) and 25-8-205(6) of the Colorado Water Quality Control Act covering AWT and variance provisions to address future impacts if and when they develop.

In summary, public participation and careful deliberation have resulted in regulations that will protect the quality of the waters of the Lower Colorado River Basin through classifications and standards that are economically reasonable in terms of the costs to the municipalities lying within the region.

III.FISCAL IMPACT: PRIVATE SECTOR

Eight private sector entities identified potential economic impacts as a result of the proposed standards in this basin: Union Oil Company, Exxon, Cathedral Bluffs, Axial Basin Ranch Coal Company, Colowyo Coal Company, Trapper Mining Company, Utah International Inc., and Talboy's Trailer Park. Other parties could be potentially affected at some time in the future, but such impacts are unlikely or hypothetical and have not been quantified.

Talboy's Trailer Park is a private-sector domestic discharge that should not be impacted by these classifications and standards as the receiving waters have a high flow.

Union Oil Company was concerned with an aquatic life classification for a segment of East Fork Creek. Testimony indicated that such a classification could potentially force them into several alternative plans regarding the disposal of spent oil shale. Cost figures were not distinct except in terms of order of magnititude. The Commission found that the indistinct nature of the cost evidence precluded specific analysis of the economic impact. There was no clear way to assign all or part of the costs explicitly to water quality issues nor was there clear indication of the incremental impact of the regulations. The Commission finds at this time that a seasonal qualifier for this segment is an economically reasonable way in which to address the concerns of Union Oil Company until such time as evidence is forthcoming identifying the specific incremental costs associated with their proposed project and the regulations as finally adopted.

Exxon was concerned that an aquatic life classification for parts of Davis Gulch and Middle Fork that lies wholly within the boundaries of their property. It was their contention that the proposed use classifications for these segments to prevent economic costs to protect nonexistant uses, the Commission left segment 11-c unclassified. This was found to be the most economically reasonable manner in which to treat this heavily impacted private property.

Cathedral Bluffs was concerned with the use classifications associated with portions of the Piceance drainage. It was their argument that the majority of the basin did not support aquatic life in any significant way and an aquatic life classification would force them to continue a no-discharge mode of treatment. The commission found that the classification was perhaps marginally appropriate but that the metals standards associated with it would cause a serious hardship to agriculture due to Cathedral Bluffs' method of treatment. The Commission found the most economically reasonable action would be to recognize agariculture to be a higher and more economically valuable use and to modify the standards for several metals to allow for Cathedral Bluffs to discharge their process waters. This was believed to have a negligible impact on the aquatic use of the stream while allowing agriculture users access to water that was previously wasted through evaporation.

The Axial Basin Ranch Company was concerned with a water supply classification that was believed by them to pose a potential for impacting the future of coal development within the region. Little Bear Creek was found by the Commission to have quality sufficient for water supply but considered that there was no wataer supply in place and the Town of Craig has several water supply options if they grow. There were no water rights nor decrees that would lead the Commission to believe that a water supply use would be reasonably expected in the foreseeable future. Thus, the Commission found that the most economically reasonable course would be to drop the water supply classification in favor of future coal development.

Utah International Inc., Axial Basin Ranch Company, Trapper Mining Company, and Colowyo Coal Company were concerned that the aquatic life classification for all of the tributaries to the Upper Yampa River may not be accurate. Several of the tributaries were found to be primarily dry gulches that would only carry water during storm events and spring runoff. Resegmentation allowed the Commission to retain aquatic life classifications where appropriate and remain responsive to the concerns of the coal companies. There was no specific testimony detailing what economic impact this would prevent but it was generally assumed that it would result in savings of potential treatment. The Commission found it reasonable to protect against unspecified potential costs in this case because there was no corresponding beneficial use to protect.

Through evaluation of expert testimony and careful deliberative consideration, the Commission has taken steps to minimize the economic impact impact of these classifications and standards upon the private sector. As adopted, these classifications and standards will have a negligible impact upon the private sector while protecting current and achievable beneficial uses.

IV.CONCLUSION

It is important to add that the Commission took several steps in many drainages to protect rare, threatened and endangered species. The Colorado River Cutthroat was specifically protected by a high quality designation on Northwater and Trapper Creeks as well as Trappers Lake. The Commission found these segments to be critical spawning sites and considers the protection of this species to be important to the public at large. The Commission also heard testimony regarding the Humpback Chub, the Bonytail Chub, and the Colorado Squawfish. These last three species are on the national endangered species list. The Commission finds the protection of these species to be important to the public and was particularly sensitive to the testimony regarding what would be necessary to protect them. One in particular, the Colorado Squawfish, is found only in Colorado and portions of Utah. The Commission believes that it has accorded sufficient protection to these species through the classifications and standards it has adopted, and that this action is economically reasonable in that no discharger was found to face the potential of a cost impact. Considering the irrepairable nature of extinction, the Commission finds the preservation of these species to be of significant value to the public.

It is concluded that the Commission has strenously considered the economic factors at issue in this basin and that this regulation is economically reasonable both in terms of potential costs that may result, and in terms of the beneficial uses to be protected.

STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE SEPTEMBER 12, 1986:

The provisions of 25-8-202 (1)(a)(b) and (2); 25-8-203; and 25-8-204, C.R.S. provide the specific statutory authority for consideration of the attached regulatory amendments and also the statements of Basis and Purpose and Fiscal Impact in compliance with 24-4-103(4) C.R.S.

BASIS AND PURPOSE:

At the triennial review conducted April 7, 1986, no recommendations were received from the public. Nonsubstantive amendments were recommended by the Water Quality Control Commission to correct clerical errors. In adopting these corrections the Commission considered the economic reasonableness of its action. Except as specified, the corrections in no way change the classifications and numeric standards originally adopted by the Commission.

FISCAL IMPACT STATEMENT:

The Water Quality Control Commission found that the clerical corrections to its regulation 3.7.0 have no fiscal impact.

5 CCR 1002-37.10

39 CR 03, February 10, 2016, effective 3/1/2016
39 CR 03, February 10, 2016, effective 6/30/2016
40 CR 03, February 10, 2017, effective 6/30/2017
41 CR 03, February 10, 2018, effective 6/30/2018
42 CR 04, February 25, 2019, effective 6/30/2019
42 CR 17, September 10, 2019, effective 12/31/2019
43 CR 03, February 10, 2020, effective 6/30/2020
44 CR 05, March 10, 2021, effective 6/30/2021
44 CR 17, September 10, 2021, effective 12/31/2021
45 CR 17, September 10, 2022, effective 9/30/2022
46 CR 10, May 25, 2023, effective 6/14/2023