Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-32 - REGULATION NO. 32 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR ARKANSAS RIVER BASIN
Section 5 CCR 1002-32.28 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE (September 1998 Rulemaking)

1. Upper Arkansas Segment 1b - Temporary Modifications

This segment previously had temporary modifications for manganese, lead and zinc which expired at the end of 1997. In this hearing, Climax Molybdenum Company proposed that ambient quality-based standards be adopted for these parameters on this segment. Based on the evidence presented to the Commission, the expired temporary modifications were reviewed and were readopted to March 31, 2002. This was done to accommodate TMDL studies that are underway on the segment, which the Commission understands will include an opportunity for participation by Climax Molybdenum Company.

2. Upper Arkansas Segments 2b and 2c - Temporary Modifications

Upper Arkansas segments 2b and 2c had temporary modifications (Cd(ch) and Zn(ch) for 2b and Zn(ch) for 2c) that were due to expire at the end of 1998. The quality of water in these segments will be affected by the Superfund remediation efforts on California Gulch, which are not yet complete. Based on evidence presented to the Commission, the existing temporary modifications were extended until March 31, 2002. In addition, the Commission's action clarifies that underlying Zn(ac) standards = TVS will be in place for these segments, with a temporary modification of "no Zn(ac)" until March 31, 2002.

3. Upper Arkansas Segment 9 - Temporary Modifications

This segment, which is the lower portion of Iowa Gulch, had a temporary modification for zinc that was due to expire at the end of 1998. Based on the evidence submitted, the Commission has adopted a revised temporary modification for "Zn(ac/ch) = existing quality, if determined less stringent than TVS" , with a March 31, 2002 expiration date. The adoption of the narrative temporary modification to the underlying zinc standards is in recognition that the only available dissolved zinc data for segment 9 at the time of the hearing was exclusively in the most downstream reach of the segment and may not be representative of the quality found throughout the segment. Dissolved zinc data collected in the late 80's and early 90's in segment 8b which is immediately upstream of segment 9 would tend to indicate that the zinc levels in the upstream portion of segment 9 could be significantly higher than the 85th percentile of the present available data and may exceed TVS values. It is understood that ASARCO, the operator of the Black Cloud Mine which discharges to segment 8b, will collect additional data from several points in segment 9 over the duration of the temporary modification. This should establish the existing quality in segment 9. The Commission hopes that this information will be useful in determining the appropriate standards for the segment.

4. Upper Arkansas Segments 21, 22a and 22b - Site-specific Standards

Segment 22 has been divided into two segments, Arequa Gulch and Squaw Gulch. Arequa Gulch, Segment 22a, was previously classified by the Commission in 1995. At that time, the Commission adopted table value water quality standards and temporary modifications. This hearing was contemplated to review and revise the standards, as necessary.

Arequa Gulch

For this hearing, Cripple Creek and Victor Gold Mining Company (CC&V) proposed site-specific standards for Arequa Gulch based on application of 5 CCR 1002-31.7 ii) Ambient Quality-Based Standards, and on 5 CCR 1002-31.7 Site-Specific-Criteria-Based Standards. At the outset of the hearing, CC&V withdrew its proposed standards based on 5 CCR 1002-31.7 in view of the Division's and EPA's general support for the proposed site-specific-criteria-based standards (with the exception of pH). CC&V emphasized that its election to withdraw the ambient quality-based standards proposal was not intended as an admission by CC&V that the water quality in Arequa Gulch is not natural or irreversible human-induced. The Commission is making no determination as to the "natural or irreversible human-induced quality" issue in this hearing.

The site-specific standards for metals in Arequa Gulch adopted by the Commission in this hearing are based on 5 CCR 1002-31.7. However, the use attainability analysis showed that the recalculation procedure resulted in water quality standards that are less restrictive for some parameters than existing water quality. In light of this, CC&V proposed that the standards for Arequa Gulch for aluminum, manganese and zinc be the more restrictive of either the recalculated value or the existing water quality value based on the 85th percentile of the data. More specifically, the aluminum acute and chronic standard of 11,000 µg/L is recalculation-based; the chronic manganese standard of 6,300 µg/L and chronic zinc standard of 800 µg/L are existing quality-based; and the acute manganese standard of 18,500 µg/L and acute zinc standard of 3,500 µg/L are recalculation-based. The Division supported this more conservative proposal and the Commission adopted it.

The Division and EPA opposed establishment of the site-specific-criteria-based standard for pH of 5.5 - 9.0 proposed by CC&V. The Division and EPA stated, however, that they would support a temporary modification of 5.5 - 9.0 with underlying standards of 6.5 - 9.0 in order to provide time for additional and appropriate studies to be performed by CC&V to evaluate CC&V's claim that the 5.5 pH level is protective of the aquatic life use in Arequa Gulch. CC&V agreed with this approach for pH so long as the temporary modification is not construed as a determination that the water quality in Arequa Gulch is not natural or irreversible human-induced. Citizens for Victor! questioned whether temporary modifications could be assigned without deciding that the existing water quality is caused by human-induced conditions.

The Commission believes that adoption of a pH temporary modification with a limited duration is consistent with applicable regulations and appropriate in view of the facts presented. The temporary modification adopted for pH reflects current in-stream water quality. The Commission believes that in these circumstances the adoption of a short-duration temporary modification reflecting that existing quality is an appropriate, conservatively protective course of action. The Water Quality Control Commission recognizes that this action suggests that the existing quality may be human-induced, but the Commission is making no determination on that issue at this time. Rather, the Water Quality Control Commission is reserving any determination as to whether pH levels reflect natural or irreversible human-induced conditions. That issue may need to be resolved in a future hearing addressing this segment, depending on the results of pending studies.

The pH temporary modification recognizes existing water quality while holding out the possibility that these conditions may be correctable in the future if additional studies should demonstrate that a narrower pH range is necessary to protect aquatic life in Arequa Gulch. In the present circumstances, it appears that the appropriate first step toward "eliminating the need for the temporary modification" is completion of the additional studies. In view of the above, the Commission adopted the temporary modification for pH of 5.5 - 9.0 until November 30, 2000, which the Commission believes should provide adequate time to complete the anticipated studies, so that the issue of appropriate pH standards can be resolved.

Citizens for Victor! also argued in this hearing that Arequa Gulch should be bifurcated into two segments, with more restrictive standards applying to the downstream reach. The Commission believes that the evidence submitted in this hearing is not adequate to warrant resegmentation of Arequa Gulch at this time. However, the Commission requests that additional information be developed regarding water quality in different reaches of Arequa Gulch, so that this issue regarding segmentation can be reviewed with better information in the future.

Squaw Gulch

Segment 22b is a new segment for Squaw Gulch from its source to the confluence with Cripple Creek. This segment is classified aquatic life cold 2, agriculture and recreation 2, and is designated use-protected. Because flow seldom exists in Squaw Gulch, only physical and biological standards have been adopted. This is consistent with the Commission's action in similar segments elsewhere in Colorado.

Cripple Creek (Segment 21)

The temporary modifications adopted in 1995 for iron and manganese for Cripple Creek, Segment 21, have been deleted.

5. Fountain Creek Segments 2a and 2b - Resegmentation and Adoption of Ambient Standards

The mainstem of Fountain Creek from immediately above the confluence with Monument Creek to the confluence with the Arkansas River (formerly Segment 2) was bifurcated into the two segments described below upon analysis of water quality data that showed that differing ambient standards are appropriate for the two segments. The elevation of the water quality above table value standards for the parameters is due to natural and/or uncontrollable sources of pollutants.

Fountain Creek Segment 2a - Mainstem of Fountain Creek from immediately above the confluence with Monument Creek to immediately above the confluence of Steele Hollow Creek. Ambient standards adopted: SO4 = 330 mg/l; Se(ch) = 6 ug/l; Fe(ch) = 8000 ug/l (which is the same as the previous iron standard for segment 2).

Fountain Creek Segment 2b - Mainstem of Fountain Creek from immediately above the confluence of Steele Hollow Creek to the confluence with the Arkansas River. Ambient standards adopted: S04 = 490 mg/l; Fe(ch) = 5100 ug/l (Trec); Se(ac) = 20 ug/l (no chronic standard).

6. Lower Arkansas Segment 1a, 1b, and 1c - Resegmentation, Adoption of Ambient Standards and Deletion of Special Standards

The mainstem of the Lower Arkansas River from immediately above the confluence with Fountain Creek to the Colorado/Kansas border (formerly Segment 1) was bifurcated into the three segments described below upon analysis of water quality data that showed that differing ambient standards are appropriate for the three segments. The elevation of the water quality above table value standards for the parameters is due to natural and/or uncontrollable sources of pollutants.

Lower Arkansas Segment 1a - Mainstem of the Arkansas River from immediately above the confluence with Fountain Creek to immediately above the Colorado Canal headgate near Avondale, Colorado. Ambient standards adopted: S04 = 310 mg/l; Fe(ch) = 1900 ug/l (Trec); Se(ch) = 17 ug/l; Temporary Modifications for Se(ac), Se(ch) and S04= existing quality until 7/1/2008.

Shallow groundwater in the University Park and Fairmount areas of Pueblo has very high concentrations of selenium and sulfate. These two constituents are naturally occurring in the Pierre Shale formation that underlies this portion of Pueblo. While urbanization of the City is an irretrievable human-caused condition that may result in increased water infiltration into and dissolution of selenium and sulfate in the shale, high natural ground water levels may also contribute to the problem. Much of this ground water flow is intercepted by basements in the University Park and Fairmount subdivisions and then in turn it is discharged to the sanitary sewer. The contribution of selenium and sulfates from industrial or other sources to the sewer system is virtually nil compared to the basement source. The Commission has determined that prohibiting this discharge to the sewer system would probably increase the amounts of selenium reaching Fountain Creek and subsequently Arkansas River segment 1a through naturally occurring groundwater flow and would have a substantial and widespread economic and social impact. Approximately 50 percent of the selenium load to the Arkansas River is removed through the serendipitous interception and removal of selenium by the Pueblo Wastewater Treatment Plant. No adverse impacts on beneficial uses from the discharges of selenium or sulfates have been documented. The Commission agrees with the Division and the parties that a long-term temporary modification for selenium (existing quality until 7/1/2008) for this segment is warranted, with underlying standards set at the 85th percentile of ambient conditions. The temporary modification will be reviewed every three years, but will expire in 10 years. This is in recognition that science, technology or nonpoint management may sufficiently advance in the future so that economically reasonable means of reducing selenium become available.

Lower Arkansas Segment 1b - Mainstem of the Arkansas River from immediately above the Colorado Canal headgate to the inlet of John Martin Reservoir. Ambient standards adopted: S04 =1090 mg/l; Fe(ch) = 1900 ug/l (Trec); Se(ch) = 16 ug/l. Comments received from the City of La Junta expressed concerned that the original proposal for this hearing would have relaxed the previous sulfate standard in effect for these waters. The Commission notes that the final standard adopted is somewhat more stringent than the previous standard.

Lower Arkansas Segment 1c - Mainstem of the Arkansas River from the outlet of John Martin Reservoir to the Colorado/Kansas border. Ambient standards adopted: S04 =2400 mg/l; Mn(ch) = 290 ug/l; Se(ch) = 19 ug/l.

In reviewing the above segments, the Commission elected to delete section 32.5 which had established a "variance" to the table value standard for free cyanide for a portion (identical to now segment 1a) of segment 1. It was determined that the basis and purpose for the special standard which was established in 1980 to protect a discharger (no longer in existence) from potential economic harm was no longer valid.

The Commission deleted section 32.5 which established site-specific dissolved oxygen (D.O.) standards for segment 1a.This action was taken because certain assumptions made for the justification of the standards in 1981 never materialized and a use attainability analysis (UAA) was not done which meets present day criteria. Because of concerns on the effects of the removal of the D.O. standards for segment 1a on the City of Pueblo whose wastewater treatment plant discharges to segment 1a, the Commission adopted a 3-year temporary modification to the 5 mg/l D.O. standards for segment 1a. It is anticipated that during the 3-year period, the City in consultation with the Division will develop a UAA that will provide information to the Commission at the next rulemaking hearing on the need for site-specific D.O. standards for segment 1a and, if needed, proposed standards.

7. Selenium Standards

The Commission in 32.6 revised the table value standards (TVS) for selenium applicable to aquatic life segments in the Arkansas Basin to 20 ug/l acute and 5 ug/l chronic. This change reflects the TVS values in 31.16 of the "Basic Standards" which were adopted in October of 1995.

The Commission applied the new TVS values to most aquatic life segments of the Arkansas Basin that had the previous TVS standards in place. Exceptions were made for segments that showed existing concentrations of selenium exceeding the chronic TVS of 5 ug/l due to natural and/or uncontrollable sources of selenium and there was no evidence of interference with classified uses. These segments are:

8. Manganese

The Commission adopted an addition to section 32.6(3) to reflect the new table value aquatic life criteria for manganese. The aquatic life manganese criterion was changed in 1998 revisions to the Basic Standards from the 1,000 ug/l chronic to acute and chronic hardness based equations. On all segments with aquatic life uses with no water supply classification, the dissolved manganese standard of 1,000 ug/l was stricken and replaced with the acute and chronic aquatic life TVS.

9. Changes Necessary to Comply with "Swimmable" Requirements

In continuation of the Commission's efforts comply with the federal Clean Water Act requirements that all waters of the nation be suitable for recreation in and on the water, two existing recreation class 2 waters for which recreational use was documented were upgraded to recreation class 1 and fecal coliform standards of 200 /ml were adopted. The waters upgraded are: Upper Arkansas segment 20 (Fourmile Creek) and Two Buttes Pond below Two Buttes Reservoir (moved from Lower Arkansas segment 9a to segment 10).

10. Water + Fish Organics Applied to Aquatic Life Segments

It is the policy of the Commission to establish the water + fish organics standards found in the Basic Standards for those class 2 aquatic life segments where fish of a catchable size and which are normally consumed are present and there is evidence that angling takes place on a recurring basis. Based on these criteria and the testimony submitted, the Commission has chosen to assign the water + fish organics standards to the following class 2 aquatic life segments:

Cimarron River segment 2

In addition, the Commission has added several lakes and reservoirs to existing class 1 segments which would afford them the protection of the water + fish standards. These waters were identified by the Colorado Division of Wildlife as public waters which are stocked with gamefish which are regularly caught and consumed. Most of these waters had previously been included under the all tributaries, lakes and reservoirs characterization of class 2 aquatic life segments that had the minimal set of standards. That classification and standards are intended to be applied to intermittent streams or reservoirs with only rudimentary aquatic life. The segments to which waters were added, and the waters are:

The Water Quality Control Division originally proposed also moving Runyon Lake from Middle Arkansas segment 4 (which has an aquatic life warm 2 classification) to Middle Arkansas segment 3. The Commission has decided to leave Runyon Lake in segment 4 at this time, until additional information is available regarding what species are present in this segment and whether they are reproducing.

The City of Colorado Springs opposed the inclusion of Prospect Lake into Fountain Creek Segment 7. In 1988, the Division believed that the Lake, which is an entirely man-made recreational facility, did not constitute "waters of the state" since it was filled entirely with potable water and apparently qualified for the exemption found in C.R.S. 25-8-103(19), i.e. "waters withdrawn for use until use and treatment have been completed." In 1997, the City began to pump a limited amount of ground water into the Lake. It has not been demonstrated to the Commission that there is no connection between the Lake and the underlying aquifer. Currently, the Division does believe that Prospect Lake constitutes "waters of the state."

Based on the evidence presented, the Commission believes that the Lake is waters of the state and should be included within Segment 7. The Commission is aware of the fact that both fishing and swimming activities have occurred in the Lake over the past 20 years without any observed adverse impacts on either use. The Lake has been filled with chlorinated potable water and receives additional chlorination for protection of the swimming use. The Commission acknowledges that it will take time to determine the current ambient water quality of the Lake, re-examine the appropriate classifications for the Lake, and determine what measures, if any are required to achieve attainment of the standards. In addition, the City may need time to properly budget for the implementation of these measures. Given these facts and the indication of no current concerns associated with the uses of the Lake, the Commission granted the City's request for a temporary modification of "existing quality" which will expire on March 31, 2002. During that time, the City and Division will undertake such steps as are necessary to re-examine the appropriate use classifications for the Lake, and determine what measures must be taken to ensure that the standards are attained.

11. Full Standards Not Applied to Aquatic Life Segments

The Commission reviewed information regarding aquatic life class 2 segments where the full set of inorganic aquatic life protection standards have not been applied. These are generally often dry segments with only rudimentary aquatic life. The Commission's policy has been that rather than adopt the full set of inorganic standards for these segments, standards for dissolved oxygen, pH and fecal coliform are protective. The Commission has upheld the previous decisions that there is a very low probability that any of the few dischargers located on these segments would discharge toxic effluents. The segments where this policy was followed are:

Upper Arkansas Segment 14

Upper Arkansas Segment 26

Middle Arkansas Segment 4

Middle Arkansas Segment 15

Fountain Creek Segment 4

Lower Arkansas Segment 2

Lower Arkansas Segment 6b

Cimarron River Segment 1

12. Ambient Quality-Based Standards

The Commission reviewed information regarding use attainment on segments in the Arkansas River basin with standards less restrictive than the table value standards. The following segments were reviewed and the existing ambient standards were deemed appropriate all due to natural and/or man-induced irreversible causes:

The Commission also instituted ambient standards on the following segments based on the determination that elevation of the water quality above table value standards for the parameters was due to natural and/or uncontrollable sources of pollutants.

1. Hazardous Materials and Waste Management Division

2. Resurrection Mining Company

3. Climax Molybdenum

4. Cripple Creek & Victor Gold Mining Company (CC&V)

5. Citizens for Victor!

6. ASARCO Incorporated

7. City of Colorado Springs

8. City of Pueblo

9. Board of Water Works of Pueblo, Colorado

10. U.S. Fish and Wildlife Service

11. Colorado Division of Wildlife

12. US EPA Region VIII