5 Colo. Code Regs. § 1002-32.15
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 6. The purpose of this language is to explain the new references to "table value standards" (TVS) that are contained in the Tables. The other changes considered and adopted are addressed below by segment.
Upper Arkansas segments 12, 13, 15, 16a, 16c, 17a, 17c, 18a, 19, 20, 23, 24
Middle Arkansas segments 5, 6, 9, 10, 11, 14, 16, 19, 20, 21
Fountain Creek segments 4 and 5
Lower Arkansas segments 3, 5b, 6a, 8, 11
Numerical standards for metals for these segments have in most instances previously been based on table values contained in Table III of the 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 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, in addition to these standards changes, the use classifications have been revised where necessary so that each of these segments has the following classifications:
Recreation - Class 1
Cold Water Aquatic Life - Class 1
Water Supply
Agriculture
These classifications are appropriate because the existing quality is adequate to protect these uses.
Third, a High Quality 2 designation has been established for each of 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.
Wilson Creek, Upper Arkansas segment 23, has been reclassified from aquatic life cold, class 2 to aquatic life class 1, with a High Quality 2 designation. A field review by the Division indicates the presence of aquatic life in the segment including reproducing brook trout. Table value standards were adopted because ambient water quality is better than specified by the standards at ambient hardness.
Upper Arkansas segments 1a, 25
Middle Arkansas segments 22, 23, 24
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. Upper Arkansas segment 1a is within the Collegiate Peaks wilderness area. Upper Arkansas segment 25 and Middle Arkansas segments 22, 23, and 24 contain an endangered species of cutthroat trout. In addition, the following use classifications and associated table value standards were adopted for these segments:
Recreation - Class 1
Cold Water Aquatic Life - Class 1
Water Supply
Agriculture
These classifications and standards are appropriate based on the best available information regarding existing quality. These provisions would apply in the event that degradation is determined to be necessary following an activity-specific antidegradation review.
Upper Arkansas segments 8a1, 8a2, 14, 22, 26
Middle Arkansas segments 4, 13, 18
Fountain Creek segments 3a, 8
Lower Arkansas segments 2, 6b, 13
Cimarron River segment 1
These segments all qualify for a use-protected designation based on their present classifications. Lower Arkansas segment 6b and Upper Arkansas segments 8a1, 8a2, and 14 have cold water class 2 classifications. The remaining segments have warm water class 2 classifications. Existing standards are recommended because these segments either have no metal standards or because no dissolved metals data is available for them at this time (Upper Arkansas segments 8a1 and 8a2).
Middle Arkansas segments 3, 7, 8, 15, 17
Fountain Creek segments 6 and 7
Lower Arkansas segments 1, 4, 7, 9, 14
Cimarron River segment 2
Middle Arkansas segments 7, 8, 15 and 17; Fountain Creek segments 6, 7; Lower Arkansas segments 1, 4, 7, 9 and 14, and Cimarron River segment 2 are qualified for a use-protected designation because they are classified recreation class 2 and aquatic life warm class 1 or 2.
Table value standards are adopted for all constituents, except as noted below.
Segment | Constituent(s) |
Fountain Creek, 7 | Fe |
Lower Arkansas, 1 | SO4, Fe |
Upper Arkansas segments 1b, 1c, 2a, 2b, 2c, 3, 4, 5, 6, 10, 16b, 17b, 21, 27
Middle Arkansas segments 1, 2, 12
Fountain Creek segments 3b, 9
Lower Arkansas segments 5a, 10, 10a, 12, 12a
The principal issues considered for segment 1b of the Upper Arkansas were the addition of an agriculture classification and the assignment of ambient based standards for zinc, lead, and copper. Consideration of a use-protected designation was also discussed but rejected because the data was in total recoverable form and not dissolved. The Commission declined to adopt the agriculture classification because although the quality of the water would support the use, the water was not currently being used for this purpose and was not likely to be in the future. Table value standards were adopted for zinc, lead and copper with a temporary modification of 250 ug/l for zinc, 12 ug/L for lead and 10 ug/L for copper, each as total recoverable, to expire December 31, 1992. In setting these standards, the Commission rejected deletion of the runoff data and considered adopting seasonal standards. Seasonal standards were not adopted because this would result in spring runoff standards several times higher than the acute criterion.
The Commission's action in adopting the temporary modifications and underlying standards for zinc, lead, and copper on segment 1b assumes that dissolved data will be available for the next triennial review (1991), and that revisions to both the temporary modifications and the underlying standards, if appropriate, can be made at that time.
On segments 2c and 3 the Commission has adopted temporary modifications and underlying standards due to the metals loading from the Leadville area, i.e. California Gulch and the Leadville Tunnel. On segment 2c an underlying TVS standard for cadmium was adopted with a 3-year temporary modification of 2.3 ug/l. The zinc standard was set at 118 ug/l with a 3-year temporary modification of 565 ug/l. On segment 3, an underlying zinc standard of 130 ug/l was adopted with a 250 ug/l temporary modification, the temporary modification only in effect on that portion of the segment from Lake Creek to US Highway 25. On both segments the underlying zinc standard is based on the EPA chronic zinc criterion for the average hardnesses in each segment. This modification from Colorado's criterion of 45 ug/l was justified by site-specific Division of Wildlife bioassays in these reaches of the Arkansas River. The temporary modification to the cadmium and zinc standards are based on the 85 percentile values of the dissolved cadmium and zinc data available on each segment. It is felt that the underlying standards will easily be obtained in the next 3 years with the clean-up of the Leadville Tunnel and the Yak Tunnel on California Gulch.
Segment 4 is classified cold water aquatic life class 1, recreation class 1. Table value standards are met for all constituents in this segment except total recoverable iron. An ambient standard of 1,200 ug/l is adopted for iron and table values are adopted for the rest.
The water supply use classification was removed from Upper Arkansas segment 9 because the ambient concentration of sulfate and manganese in the segment are inconsistent with the criteria for water supply and there is no existing or historic water supply uses of segment 9 waters.
New segments, Lower Arkansas 10a and 12a were created for Lakes Meredith and Henry, respectively. Lower Arkansas segments 10 and 12, which include several plains reservoirs, were designated high quality class 2 because they have the necessary use classifications. With respect to Lakes Meredith and Henry, the City of Colorado Springs testified that these two reservoirs are frequently dried up during the exercise of water rights, and thus should not be designated high quality.
Existing use classifications (Recreation 1, warm water aquatic life 1, water supply, and agriculture) and TVS were adopted for segments 10a and 12a. Segments 10a and 12a were not designated high quality 2.
Consideration of standards for Upper Arkansas segments 2a, 2b and 6 was continued until April, 1990 because of concerns that proposed standards were not protective of aquatic life and may be inconsistent with clean-up goals of the Leadville Drain and California Gulch Superfund projects. Existing classifications remain in place for all three segments. For segment 6, all numerical standards except fecal coliform have been deleted. No party objected to this change. For segments 2a and 2b, the Commission has adopted table value standards as the underlying numerical standards, with eight- year temporary modifications based on existing ambient quality.
At the time that the original classifications and standards were adopted for segments 2a and 2b, in 1982, the Commission concluded that the prospects for future improvement of water quality were "too speculative" to adopt more-stringent-than-ambient water quality standards for these segments. Since then, the prospects for improvement have changed substantially. In view of the pending treatment of Leadville Tunnel water and the Superfund actions addressing California Gulch clean-up, the Commission now believes that it is appropriate to adopt table value standards for these segments, to serve as a goal for future clean-up, and protection from any new discharges.
There is some uncertainty at this time as to the precise metals levels that will be achieved instream following pending cleanup actions. The eight-year temporary modifications will not only allow time for substantial cleanup to occur, but will allow two triennial reviews to further assess the appropriateness of the underlying standards before they go into effect. If better information available in the future indicates that different underlying standards are appropriate, the standards can be modified at that time. As a matter of policy, the Commission does not believe that leaving ambient-quality-based standards in place as the sole standards for these segments at this time is appropriate, since that would suggest that the existing quality is acceptable for the future. That result would ignore the clean-up actions already planned and would be inconsistent with the Water Quality Control Act policy of improving water quality where necessary and reasonable.
Parties to the Hearing
FINDINGS REGARDING BASIS FOR EMERGENCY RULE SEPTEMBER 11, 1990:
The Commission held this emergency rulemaking hearing to readopt the classifications and numeric standards for one segment of the Arkansas River Basin to correct typographical errors in the original filing. The affected regulation was amended on June 5, 1990 and was filed within the required timeframes with the Secretary of State's Office and the Office of Legislative Legal Services. The Commission learned shortly after the filings that there was an error on page 12, segment 2, Fountain Creek of the tables.
The Commission finds that the immediate adoption of this regulation is imperatively necessary for the preservation of public health, safety, or welfare and that compliance with normal notice requirements would be contrary to the public interest. Emergency adoption is necessary to assure that the published regulation is consistent with the regulation that the commission adopted, to avoid confusion for the public and to assure that the revised discharge permit for the City of Colorado Springs is consistent with the Water Quality Control Commission's action.
5 CCR 1002-32.15