5 Colo. Code Regs. § 1002-32.34
The provisions of C.R.S. 25-8-202(1)(a), (b) and (2); 25-8-203; 25-8-204; and 25-8-402; provide the specific statutory authority for adoption of these regulatory amendments. The Commission also adopted in compliance with 24-4-103(4) C.R.S. the following statement of basis and purpose.
BASIS AND PURPOSE
Some renumbering and/or creation of new segments was made in the basin due to information which showed that:
Upper Arkansas segment 12a: | Chalk Creek |
Upper Arkansas segment 14a: | Big Red, Little Red, Rush and Hardscrabble Creeks |
Upper Arkansas segment 15: | Newlin Creek from Upper Arkansas segment 14 |
Middle Arkansas segment 4a: | Wildhorse Creek |
Middle Arkansas segment 4b: | Rock, Salt and Peck Creeks from Middle Arkansas segment 4d |
Middle Arkansas segment 4c: | Chico Creek and tributaries from Middle Arkansas segment 4d |
Middle Arkansas segment 7: | Graneros and North Muddy Creeks from Middle Arkansas 4d |
Middle Arkansas segment 11: | Turkey Creek from Lower Arkansas 2 |
Middle Arkansas segment 17: | North Apache Creek from Lower Arkansas 2 |
Middle Arkansas segment 18a: | Boggs Creek |
Fountain Creek segments 2a, 2b: | Segment boundary moved from Steele Hollow Creek to "a point immediately above the Highway 47 Bridge" |
Fountain Creek segments 7a, 7b: | Divide former segment 7 into 7a and 7b |
Lower Arkansas 3b: | Dry tributaries from Lower Arkansas 3a |
Lower Arkansas 4: | Lorencito Canyon from Lower Arkansas segment 6 |
Lower Arkansas segment 5b: | Lake Dorothey from Lower Arkansas 2 |
Lower Arkansas 9a: | Cheyenne Creek, Buffalo Creek from Lower Arkansas 9b |
Lower Arkansas 13: | Ramah Reservoir from Lower Arkansas 2 |
The Commission adopted table value standards for selenium and temporary modification of existing ambient quality for selenium for
Middle Arkansas segments 2, 3, 4a, 5, 10, 12, and 18a
Fountain Creek segments 2b and 6
Lower Arkansas segment 1a, 1b, 1c, 3a, 4, 7, 9a, 9c, and 11
The temporary modifications were adopted pursuant to section 31.7 of the Basic Standards regulation, based on the fact that there is significant uncertainty as to the appropriate underlying selenium standard for these segments.
The biological standards were updated to include the dual standards for E. coli and fecal coliform, which were adopted by the Commission in the 2000 revisions to the Basic Standards As stated in the statement of basis and purpose for the Basic Standards revisions, the Commission intends that dischargers will have the option of either parameter being used in establishing effluent limitations in discharge permits. In making section 303(d) listing decisions, in the event of a conflict between fecal coliform and E. coli data, the E. coli data will govern. The Commission believes that these provisions will help ease the transition from fecal coliform to E. coli standards.
In a continuation of the Commission's efforts to comply with the requirements contained in the federal Clean Water Act that all waters of the nation should be suitable for recreation in and on the water (known as the "swimmable" goal), the Commission reviewed all Recreation Class 2 segments. In Colorado, the "swimmable" goal translates into Recreation Class 1a, with the 200/100 ml fecal coliform and 126/100 ml E. Coli standard, and Class 1b with the 325/100 ml fecal coliform and 205/100 ml E. coli standard. Class 1a indicates waters where primary contact uses have been documented or are presumed to be present. Class 1b indicates waters where no use attainability analysis has been performed demonstrating that a recreation class 2 classification is appropriate. To maintain the existing Recreation Class 2 with the 2000/100 ml standard on a segment, it must be shown that there is minimal chance that a Recreation Class 1 activity could exist (e.g. ephemeral or small streams that have insufficient depth to support any type of Recreation Class 1 use or very restricted access).
A recreation class 1a classification of a segment is not intended to imply that the owner or operator of property surrounding and waterbody in a segment would allow access for primary contact recreation. The application of recreation classifications to state waters pursuant to these provisions does not create any rights of access on or across private property for the purposes of recreation in or on such waters. A recreation class 1a classification is intended to only affect the use classification and water quality standards of a segment, and does not imply public or recreational access to waters with restricted access within a segment.
For segments changing to recreation Class 1a because no information was available about actual recreational uses, the last paragraph of section 31.6 will apply to future changes to the recreation classification where a proper showing is made through a use attainability analysis that a recreation Class 2 classification is appropriate, without application of the other downgrading criteria in this section. Moreover, the Commission is relying in part on the testimony from EPA that completion of a use attainability analysis showing that a lower recreation classification is appropriate satisfies applicable downgrading criteria. Based on these factor, the Commission intends that in a future rulemaking hearing, the test for adopting a recreation Class 2 classification would be the same as if it had been considered in this hearing
The following segments with existing Recreation Class 1 classifications were changed to Class 1a:
Upper Arkansas segments 1a, 3, 9, 10, 12a, 12b, 13, 15, 16a, 16c, 17a, 17c, 18, 19, 20, 23, 24, 25 and 27.
Middle Arkansas segments 1, 2, 5, 7, 8, 11, 13, 16, 17, 18a, and 18b
Lower Arkansas segments 3a, 5a, 5b, 8, 10, 11, and 12
Based on the information received that showed Recreation Class 1a uses are in place or are presumed to be present in at least a portion of the segment, the Commission changed the following segments from Class 2 to Class 1a with a 200/100 ml fecal coliform and 126/100 ml E. coli standard:
Upper Arkansas segments 1b, 2a, 2b, 2c, 5, 7, 8a, 8b, 11, 14a, 14b, 16b, 17b, 21, and 26 Middle Arkansas segments 3, 4a, 4b, 4c, 4d, 6, 9, 10, 12, 14, and 15
Fountain Creek segments 1, 2a, 2b, 3, 4, 6, and 7b
Lower Arkansas segment 1a, 1b, 1c, 4, 6, 7, 9a, 9b, 9c, and 13
Cimarron segment 2
Based on evidence presented, the Commission has changed the following from Recreation Class 2 to Recreation Class 1b:
Fountain Creek segment 7a
The following segments retained their Recreation Class 2 classification with 2,000/100mL fecal coliform and 630/100 ml E. coli standard after sufficient evidence was received that a Recreation Class 1a or 1b use was unattainable.
Upper Arkansas segments 6, 22a and 22b
Fountain Creek segment 5
Lower Arkansas segment 2 and 3b
Cimarron segment 1
The Commission reviewed information regarding Aquatic Life Class 2 segments where the full set of inorganic aquatic life protection standards have not been applied. Generally, these are dry segments with only rudimentary aquatic life. The Commission's policy has been that rather than adopt the full set of inorganic standards for these segments, standards for dissolved oxygen, pH and fecal coliform provide sufficient protection.
Segments where investigation showed that fish populations were present were upgraded with the addition of the full suite of inorganic standards. These segments are:
Upper Arkansas segment 14a
Upper Arkansas segment 26
Middle Arkansas segment 4a
Middle Arkansas segment 4b
Middle Arkansas segment 4c
The Commission reviewed information regarding existing aquatic communities. The following segment's aquatic life classifications were upgraded from aquatic life class 2 to aquatic life class 1 based on information presented that showed diverse aquatic communities in these segments.
Middle Arkansas segment 4c
Lower Arkansas segment 7
There are several segments in the Arkansas River Basin that contain ambient standards. Ambient standards are adopted where natural or irreversible man-induced conditions result in water quality levels higher than table value standards. EPA had requested that the Commission review the information that is the basis for these standards as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped.
The Division reviewed the information about ambient water quality levels and provided testimony that justified revising the ambient standards on the following segments:
Upper Arkansas segment 8b: Zn(ch)
Upper Arkansas segment 10: Cu(ch)
Upper Arkansas segment 19: Mn(ch)
Upper Arkansas segment 22a: Zn(ch)
Fountain Creek segment 2a: SO4, Fe(ch), Se(ch)
Fountain Creek segment 2b: Fe(ch), SO4
Fountain Creek segment 6: Fe(ch)
Lower Arkansas segment 1a: Fe(ch), SO4
Lower Arkansas segment 1b: Fe(ch), SO4
Lower Arkansas segment 1c: Mn(ch), SO4
Lower Arkansas segment 4: Fe(ch)
Lower Arkansas segment 11: Mn(ch)
Ambient standards were removed from the following segments due to new data and/or changes to the basic standards which indicated ambient standards were no longer appropriate:
Middle Arkansas segment 5: Cd(ch) and Zn(ch)
Middle Arkansas segment 7: Cd(ch)
Middle Arkansas segment 12: Fe(ch)
Fountain Creek segment 6: Mn(ch)
Lower Arkansas segment 5a: Cd(ch)
There were several segments where temporary modifications that reflect current ambient conditions were adopted or retained. Temporary modifications were set to expire on 12/31/07 to coincide with the next triennial review. The segments and the constituents are:
Upper Arkansas segment 1b: Pb(ch), Zn(ch)
Upper Arkansas segment 2b: Cd(ch), Zn(ch)
Upper Arkansas segment 2c: Zn(ch)
Upper Arkansas segment 3: Pb((ch), Zn(ch)
Upper Arkansas segment 5: Zn(ch)
Upper Arkansas segment 7: Zn(ch)
Upper Arkansas segment 22a: pH
Middle Arkansas segment 10: Zn(ch)
Middle Arkansas segment 13: F. Coli
Middle Arkansas segment 18a: Zn(ch)
Fountain Creek segment 1: F. Coli
Lower Arkansas segment 1a: SO4
Lower Arkansas segment 3: Fe(ch)
Lower Arkansas segment 9c: Fe(ch)
The Commission rejected an argument by Colorado Springs that the fecal coliform temporary modification for Fountain Creek segment 1 should be specified as based on uncertainty. An additional list of segments with temporary modifications for selenium can be found at section B, above.
The organic standards were updated to include changes adopted by the Commission in the 2000 revisions to the Basic Standards (see 31.11 in Regulation No. 31). "Water + Fish" organic standards are presumptively applied to all Aquatic Life Class 1 streams which also have a Water Supply classification, and are applied to Aquatic Life Class 2 streams which also have a Water Supply classification, on a case-by-case basis. The "Fish Ingestion" organic standards are presumptively applied to all Aquatic Life Class 1 streams which do not have a Water Supply classification, and are applied to aquatic life class 2 streams which do not have a Water Supply classification, on a case-by-case basis.
The following segments have been updated with the organic standards:
Fountain Creek segment 7a: Water + Fish Organics
Fountain Creek segment 7b: Fish Ingestion Organics
Lower Arkansas segment 1b: Water + Fish Organic
Cimarron River segment 2: Fish Ingestion Organic
These segments had the Water Supply classification added to them. The associated water supply standards will now apply to segments:
Upper Arkansas segment 20 Fountain Creek segment 7a
Water supply standards were modified to conform to the changes made by the Commission in the 2000 revisions to the Basic Standards (see Regulation No. 31 at 31.11(6)). The Commission modified the water supply standards for iron, manganese, and sulfate that are based on secondary drinking water standards (based on esthetics as opposed to human-health risks). The numeric values in the tables were changed to Fe(ch) = WS (dis), Mn(ch) = WS (dis), and SO4 = WS. These abbreviations mean that for all surface waters with an actual water supply use, the less restrictive of the following two options shall apply as numerical standards, as discussed in the Basic Standards and Methodologies at 31.11(6): either (i) existing quality as of January 1 2000; or (ii) Iron = 300 µg/L (dissolved); Manganese = 50 µg/L (dissolved); Sulfate = 250 mg/L (dissolved). For all surface waters with a "Water Supply" classification that are not in actual use as a water supply, no water supply standards are applied for iron, manganese or sulfate, unless the Commission determined as the result of a site-specific rulemaking hearing that such standards are appropriate.
Numeric Standards to protect Agricultural Uses were adopted for the following segments:
Upper Arkansas segments 14b
Middle Arkansas segments 4d, and 15
Fountain Creek segment 4
Lower Arkansas segments 2, 3a and 6
Cimarron segment 1
Numeric standards to protect livestock watering were adopted for the following segment:
Upper Arkansas segment 22b
The Commission corrected several typographical and spelling errors, and clarified segment descriptions.
In addition, the following site-specific issues were addressed:
Upper Arkansas segment 2b, 2c and 6: The quality of the water in these segments will be affected by the ongoing Superfund remediation efforts in the California Gulch drainage basin. Current conditions of these segments were evaluated but the Commission chose to make no changes to the aquatic life classifications and numeric metals standards at this time, except for extending the expiration date of the temporary modifications. The State, EPA and private parties are currently engaged in the Superfund effort to address site-wide water quality issues, including setting cleanup goals. After such goals are established, it may be appropriate to hold a site-specific hearing to address standards and classifications for these segments.
Upper Arkansas segment 22a: For Upper Arkansas segment 22a (Arequa Gulch) in addition to adopting an E. coli standard, the Commission revised acute and chronic manganese standards and the chronic zinc standard.
The revised manganese standards (Mn(ac) = 5,903 ug/l and Mn(ch) = 3,674 ug/l) are based on a recalculation procedure performed by Cripple Creek & Victor Gold Mining Company, taking into account modifications recommended by EPA Region 8 staff. The recalculation methodology provides new values for manganese toxicity, which are intended to protect the aquatic macroinvertebrate community in Arequa Gulch. The Commission declined to adopt the Division's recommendation that a chronic manganese standard be set at the 85th percentile of the most recent three years of data, which the Division considered to be representative of current quality. The Commission notes that most commonly a five-year period of record has been used when assessing the current ambient quality of a water body. In addition, the Commission believes that there is uncertainty as to the factors influencing ambient metals concentrations in Arequa Gulch over the last few years. In view of these considerations, and because EPA has stated that the recalculation procedure used in this instance is acceptable, the Commission has chosen to adopt both acute and chronic standards for manganese based on that recalculation, rather than on an ambient quality level. The equations resulting from the recalculations are:
Mn(ac) = e (0.3331[ln(hardness)]+6.6874)
Mn(ch) = e (0.3331[ln(hardness)]+6.2134)
For zinc, the Commission has adopted a new chronic standard of 600 ug/l, based on the 85th percentile of the last five years of available data, to replace the previous ambient-quality based standard. The Commission chose to base the zinc standard on the last five years of data, rather than on the three-year period recommended by the Division, due to uncertainty as to the factors influencing ambient metals concentrations in Arequa Gulch over the last few years, and because a five-year period of record has most commonly been used when assessing the current ambient quality of a water body. Because there was no new zinc toxicity data available, no proposal was submitted in this hearing by Cripple Creek & Victor Gold Mining Company regarding use of a recalculation procedure to derive a zinc standard. Therefore, the Commission has made no changes to the previous recalculation based acute zinc standard adopted in 1998.
Fountain Creek segments 2a and 2b: On both segments, the Division proposed to adopt underlying table value standards with temporary modifications based on existing ambient quality. In response, Colorado Springs proposed to adopt standards based on existing ambient quality. In its rebuttal, the Division of Wildlife proposed moving the boundary between segments 2a and 2b further south to Highway 47 because selenium concentrations increase below this point. The Commission concurs in this resegmentation as more representative of the water quality in this portion of Fountain Creek.
The Commission set an ambient standard for selenium of 8 µg/l for segment 2a. The EPA has previously approved an ambient standard for the former segment 2a. In regards to segment 2b, the Commission established a temporary modification based on uncertainty of 23 µg/l, with an underlying table value standard. Other standards for these segments remain unchanged.
Fountain Creek segment 3: The selenium standard was corrected.
Fountain Creek segment 7: This segment consisted of six lakes. The Division proposed that all lakes in the segment receive a classification of water supply and that the recreational use classification be upgraded from class 2 to 1a.
Colorado Springs opposed the recreation class 1a classification for Pikeview Reservoir and submitted a use attainability analysis to support retaining the class 2 classification. Similarly, El Paso County opposed the recreation class 1a classification for the Willow Springs Ponds. The Division and EPA agreed that there is no existing primary contact recreation for these lakes, but believed that there is a potential for primary contact. They recommended a recreation class 1b classification, which was adopted by the Commission. Pikeview Reservoir and the Willow Springs Ponds are now resegmented as segment 7a.
Colorado Springs provided testimony that Prospect and Quail Lakes are not currently used, or anticipated to be used in the future, as a source of domestic water supply. Similar evidence was submitted by the Division for Monument Lake. Therefore, the "fish ingestion" organics standards, rather than "water + fish" standards, appropriately apply to these lakes, which are now resegmented as segment 7b.
Lower Arkansas segment 1a: The site specific dissolved oxygen standard was removed. This standard became unnecessary because of the recently adopted mixing zone policy.
Lower Arkansas segment 3a: The Commission determined that the tributaries identified in the Cedar Ridge proposal are significantly different from the physical characteristics of the mainstem of the Apishapa River. As a result, the Commission created a new segment to more accurately reflect the significant changes in use, physical characteristics and water quality characteristics between the dry tributaries and the mainstem of the Apishapa River in the vicinity of Aguilar, Colorado. The new segment is entitled Segment 3a of the Lower Arkansas Basin. The Commission assigned the classifications of aquatic life class 2, water supply, recreation and agriculture and applied appropriate standards to this new segment.
PARTIES/MAILING LIST STATUS FOR JULY, 2002 RULEMAKING HEARING
5 CCR 1002-32.34