5 Colo. Code Regs. § 1002-37.17
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 were adopted in the basin due to information which showed that:
Lower Yampa, Segment 3a - 3f: Tributaries to the Lower Yampa were separated out to reflect differences in the aquatic life use, water supply use, agricultural use, recreational use and designations.
Segment 3b: Named tributaries which are generally ephemeral and have less plentiful aquatic life use and the agricultural use is limited to livestock watering.
Segment 3c: The Milk Creek system has a known water supply use and has more plentiful aquatic life. The boundary on Good Spring Creek is set at the inlet to Wilson Reservoir. Wilson Reservoir and lower Good Spring Creek below Wilson Reservoir are included in this segment.
Segment 3d: Temple Gulch, Lay Creek and Morgan Gulch have more plentiful aquatic life, including species of special concern, and no known water supply use.
Segment 3e: Upper Good Spring, Taylor and Wilson Creeks have low flows and less plentiful aquatic life. Upper Good Spring Creek and Taylor Creek have a water supply use.
Segment 3f: Big Gulch was placed in a separate segment due to the presence of primary contact recreation uses.
Lower Yampa, Segments 3a and 14: Wetlands, lakes and reservoirs were added to the segment description to clarify that this is an "All" tributary segment.
Lower Yampa, Segment 6: Freeman Reservoir was separated from the tributaries to Fortification Creek to reflect its recreation 1a use and became segments 6a and 6b, respectively.
Lower Yampa, Segments 8 and 9: East Fork of the Williams Fork was separated out to reflect those waters within the Flat Tops Wilderness Area. Segment 8 had previously been deleted and is now replaced with the East Fork.
Lower Yampa, Segments 12 and 13b: Morapos Creek was moved from segment 13b to segment 12 to better reflect its cold water class 1 aquatic life use. Aldrich Lakes were separated from segment 12 into a new segment 12b to reflect its recreation la use.
Lower Yampa, Segments 14 and 20: Tributaries to the Yampa River from the Little Snake to the Green River were moved from segment 14 to segment 20 to better reflect the recreation la uses in Dinosaur National Monument and the associated watershed.
Lower Yampa, Segment 17: Tributaries to the Little Snake River were separated into segments 17a and 17b to reflect the differences in aquatic life use.
Lower Yampa, Segment 22: Tributaries to Vermillion Creek were added to this segment to reflect their recreational uses.
White River, Segments 1 and 2: Waterbodies in segment 2 were combined with those in segment 1. This combines the waters within the Flat Tops Wilderness Area. Segment 2 was deleted.
White River, Segments 4 and 5: Segments 4 and 5 were combined into segment 4 to reflect the similarity in water quality and aquatic life uses in the North Fork tributaries. Segment 5 was deleted.
White River, Segments 9 and 10: Coal Creek was separated out from segment 9 and is now included in segment 10 which better reflects its cold water class 1 aquatic life use. Lake Avery was separated from segment 10 into a new segment 10a to reflect its recreation la use with the remainder of segment 10 renamed segment 10b.
White River, Segment 13a: Wetlands, lakes and reservoirs were added to the segment description to clarify that this is an "All" tributary segment.
White River, Segments 13a and 13b: Little Spring Creek (previously identified in segment 13b as "Spring Creek") was deleted from segment 13b due to its dry nature and is now included in segment 13a. The description for segment 13b was also changed to include the entire Yellow Creek system. The aquatic life warm 2 classification is a better characterization of Yellow Creek's aquatic life use.
White River, Segments 16a and 16b: Waterbodies in segment 16b were combined into segment 16a to reflect the similarity in water quality and aquatic life uses in the tributaries to Piceance Creek. Segment 16b was deleted and segment 16a was renamed 16.
White River, Segments 17 and 18: Waterbodies in segment 18 were combined with those in segment 17 due to their similar natures and uses. Segment 18 was deleted.
White River, Segment 23: West Douglas Creek was added to segment 23 to better reflect its cold water class 1 aquatic life use.
Lower Colorado, Segments 4, 13a, and 13b: Wetlands, lakes and reservoirs were added to the segment descriptions to reflect the all tributaries system. These wetlands, lakes and reservoirs were previously unclassified.
Lower Colorado, Segments 4 and 10: Lower Rifle Creek was separated from segment 4 and moved to segment 10 to reflect its aquatic life cold 1 and recreation la uses. Segment 10 had previously been deleted and is now replaced with Lower Rifle Creek.
Lower Colorado, Segments 4 and 11g: Tributaries in the vicinity of lower Parachute Creek were separated from segment 4 to create segment 11g. These tributaries are generally ephemeral and there is no known water supply use. Since there is little or no information on aquatic life in this segment, and since the adequacy of flows to sustain aquatic life is an unresolved question, the last paragraph of section 31.6 will apply to future changes without application of the downgrading criteria in that section. This segment is classified aquatic life cold 2, recreation 2, agriculture. Numeric standards are adopted to protect recreation and agriculture, and for DO and pH.
Lower Colorado, Segment 11 h: The lower mainstem of Parachute Creek was separated from segment 4 to create segment 11 h to reflect difference in land use and in water supply use, and for consistency within the Parachute Creek drainage basin which is predominantly reflected by other basin-specific segments. The evidence does not support a water supply use classification for this segment. This segment remains classified as aquatic life cold 2 and agriculture, and is classified as recreation 1 b.
Lower Colorado, Segment 13: The tributary system to the Lower Colorado River was separated into several segments based on aquatic life uses and changes in water quality. Segment 13b was created to include tributaries known to have aquatic life class 2 uses. Segment 13c was created to include waterbodies with aquatic life class 1 uses. Evidence was submitted that indicated that high concentrations of selenium are present in portions of segments 13b and 13c. Segment 13 was renamed 13a and now excludes the new segments 13b and 13c.
Lower Colorado, Segment 14: Segment 14 was renamed 14a. Segment 14b was created to include the lower portion of Roan Creek which has an aquatic life warm 1 use. Lower Roan Creek was previously included in Segment 13.
Lower Colorado, Segment 16: This segment was deleted since no waterbodies could be identified in this segment.
Lower Colorado, Segment 19: Highline Reservoir and Mack Mesa Reservoir are now included in Segment 19 due to their aquatic life warm 1 uses and similar characteristics to the other lakes in Segment 19. These reservoirs were previously unclassified.
In March 1993, the Commission amended the Basic Standards and Methodologies for Surface Water, Regulation #31 (5 CCR 1002-31) to include wetlands in the stream classification and standards system for the State. Due to that action, it became necessary to revise the segment description for all segments of the "all tributary" type to clarify that wetlands are also part of the tributary system for a given mainstem segment. All tributary wetlands now clearly carry the same classifications and standards as the stream to which they are tributary as provided for in 31.13(1)(e)(iv).
The aquatic life manganese criterion was initially changed in the 1997 revisions to the Basic Standards (5 CCR 1002-31) from a single chronic dissolved criterion to acute and chronic hardness-based equations. The equations were further modified in the 2000 revisions to the Basic Standards. The new manganese acute and chronic equations were added as table value standards in 37.6(3). As a result of the adoption of these new TVS, all segments classified for aquatic life use that had a chronic total recoverable manganese standard of 1,000 µg/L had the 1,000 standard stricken and replaced with Mn(ac/ch)=TVS.
The regulation in 37.6 (3) listed the table value standards for selenium as Acute=135 µg/L and Chronic=17 µg/L. This was updated to reflect the existing acute and chronic criteria for selenium listed in the Basic Standards as Acute= 18.4 µg/L and Chronic= 4.6 µg/L which was adopted in 2000 by the Commission. This change means that all segments with standards for selenium given as TVS now have these lower acute and chronic standards. Because of this change, on all segments classified for a water supply use, the chronic total recoverable selenium of 10 µg/L was stricken and replaced with Se(ac/ch)=TVS.
The Commission adopted the table value standards for selenium and temporary modifications of existing ambient quality for selenium for Lower Colorado segments 13b and 13c. 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 reason for the adoption of the temporary modifications has been noted in the temporary modifications and qualifiers column of the table.
Water Quality monitoring has shown that many small drainages in the Grand Valley have selenium concentrations significantly in excess of the table value standards. The reduction of selenium, and the extent to which the current levels of selenium are the result of natural sources, reversible activities, and/or irreversible activities is unknown at this time. Therefore, it is not clear whether the table value standards are achievable in these segments. The Commission does not intend its actions to in any way impede current efforts to reduce salinity levels in the Colorado River mainstem and to implement the Grand Valley Water Management Plan. The Commission intends that the actions taken in this hearing will mark the beginning of a process to identify the appropriate long-term selenium standards for these tributaries. It is expected that the process may result in the adoption of site-specific standards for selenium in some or all of the affected segments.
Several segments or waterbodies were designated outstanding waters (OW) due to their meeting certain criteria pursuant to section 31.8 . Segments which already included wilderness areas in their description were designated OW. The water quality of the following segments met the 12 parameter test and other requirements of 31.8(2)(a):
Lower Yampa, Segment 8 White River, Segment 1
The Division proposed that a number of aquatic life class 2 waterbodies be assigned undesignated status under the state antidegradation regulation due to the presence of Colorado State species of special concern. State regulations governing the "use-protected" designation allow this exception if the Commission determines that the waters are of exceptional ecological significance. The Commission believes that a number of important issues have been raised in this hearing regarding when and how this exception should be applied, and that further examination of these issues should occur. Nevertheless, for purposes of this hearing, the Commission, based upon a concern over the protection of classified uses and the absence of evidence of potential injury to permitted entities, has decided to accept the change to reviewable water status for the following:
Lower Yampa, Segments: 3d, 16 and 22 White River, Segment 15
Based upon representations made by certain parties to this rulemaking, the Commission endorses the formation of a workgroup to address the following topics and develop recommendations to be submitted to the Commission
* The relationship between the "exceptional ecological significance" exception to useprotected designations and the aquatic life class 2 basis for applying use-protected designations
* The need for and content of guidance to determine what water bodies are exceptionally ecologically significant
* The roles of a) water quality data; b) the nexus between water quality conditions and species decline, and c) other stressors, in using this exception
* The need for and nature of any amendments to the state antidegradation regulation if the presence of species of special concern constitute a basis for modification to the antidegradation designation of a water body.
The above listed segments would then be reviewed in light of the work group recommendations in the next triennial review of these basins.
The Commission urges that the work group process to address these issues move forward as expeditiously as possible. The Commission intends that the actions taken in this rulemaking not serve in any way as a precedent with respect to decisions in future Commission rulemaking proceedings.
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 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, but for which no existing primary contact uses have been documented following a reasonable level of inquiry. A Recreation Class 2 classification must be supported by a use attainability analysis that shows that there is not a reasonable potential for primary contact uses.
There was considerable evidence and testimony submitted in this hearing regarding what activities should be considered primary contact recreation. Section 31.13 (1)(a) of the Basic Standards provides a nonexclusive list of primary contact activities. In this hearing, much discussion focused on the issue of whether "child's play" in streams that are too shallow to accommodate the primary contact uses listed in the Basic Standards should be considered a primary contact use. The Commission does not believe that a theoretical potential for child's play means that all streams should be classified Recreation Class 1a or 1b. However, the Commission concludes that the evidence submitted demonstrates that there is a potential risk of ingestion of small quantities of water by children playing in relatively shallow streams, based on the hand-to-mouth pathway, which warrants Recreation Class 1 protection in appropriate circumstances as elaborated below. Thus, such ingestion may occur in streams where whole body immersion is not likely.
This does not mean, as suggested by some, that all water bodies would be reclassified as Recreation Class 1a or 1b based on some potential for child's play. Rather, the Commission intends that a stream should be classified Recreation Class 1a or 1b due to the presence or potential for child's play only where the evidence demonstrates a likelihood of such activity on a frequently occurring basis. Therefore, child's play may be an appropriate basis for a Recreation Class la or 1 b classification in a developed area where there is easy access to a stream for children and it is likely that children will desire to play in the stream; it may not be an appropriate basis for such classifications in areas where it is not expected that children will be playing in a stream on a frequently occurring basis. Factors such as lack of adequate flow, excessive flows, remoteness from developed areas, physical limitations to access, steep banks, and visibly poor water quality may make it unlikely that child's play will take place on a frequently occurring basis. The Commission anticipates that these classification decisions will require case-by-case judgments until more experience is gathered with this issue.
A recreation Class 1a or 1b classification of a segment is not intended to imply that the owner or operator of property surrounding any 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 la 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 evidence or inadequate evidence was submitted on the record about actual or potential 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 factors, 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 la:
Lower Yampa, Segments: 1,2, 19
White River, Segments: 11, 12, 21
Lower Colorado, Segments: 1, 2, 3, 9
Based on the information received that showed Recreation Class la 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 la with a 200/100 ml fecal coliform and 126/100 ml E. coli standard:
Lower Yampa, Segments: 3f, 5, 6b, 8, 10, 12b, 13a, 13b, 15, 16, 20
White River, Segments: 1, 3, 4, 6, 10a, 23
Lower Colorado, Segments: 7, 10, 13b, 13c, 15, 19
Based on the information received, where a reasonable level of inquiry failed to identify any existing class 1 uses of the waters in these segments, the Commission changed the following segments to Class 1b with a 325/100 ml fecal coliform and 205/100 ml E. coli standard:
Lower Yampa, Segments: 3b, 3c, 3e, 4, 6a, 7, 9, 11, 12a, 17a, 18, 21
White River, Segments: 8, 10b, 14, 15, 19, 22
Lower Colorado, Segments: 5, 11h, 13a, 14a, 14b, 18
Although Wilson Reservoir, in Lower Yampa segment 3c is open to public fishing, it is on private property and is posted "no swimming". Other streams in segments 3b, 3c, and 3e are located in undeveloped areas, have limited or no public access and are generally characterized as shallow low-flow streams.
For Lower Colorado segment 17, the Commission adopted a Class 1b classification, based on inquiry that failed to identify existing uses, while retaining the 200/100 ml fecal coliform standard and adopting a 126/100 ml E. coli standard, because the segment currently meets these more stringent standards, water users on this segment support the more stringent standards and no water users or dischargers will be adversely affected.
For the following segments, the Commission adopted seasonal recreation classifications, based on evidence of differences in actual or potential recreation uses at different times of the year:
Lower Yampa, Segment 22: Class 1b, June 1 through August 31
Class 2, September 1 through May 31
White River, Segment 7: Class la, March 1 through November 30
Class 1b, December 1 through February 28
The following segments retained their Recreation Class 2 classification with 2,000/100mL fecal coliform and 630/100 ml E. coli standards after sufficient evidence was received that a Recreation Class 1a use was unattainable.
Lower Yampa, Segment: 3a, 3d, 14, 17b
White River, Segments: 9, 13a, 13b, 16, 17, 20
Lower Colorado, Segments: 4, 6, 8, 11a, 11b, 11c, 11d, 11e, 11f, 11 g, 12
The classification for Lower Yampa/Green River segments 3a, 3d, 14 and 17b are based upon the fact that the streams are ephemeral and/or intermittent and have limited access. The classification for White River segment 9 is based upon low flows and limited access through private lands. The classifications for White River segments 13a, 13b, 16, 17 and 20 are based upon the fact that the streams are ephemeral and/or intermittent. The classification for Lower Colorado segment 4 is based upon limited streamflows. The classification for Lower Colorado segment 6 is based upon limited streamflows and steep stream banks. The classifications for Lower Colorado segments 8, 1 la-g and 12 are based upon limited streamflows and limited access due to private and industrial lands.
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 aquatic life was present were upgraded with the addition of the full suite of inorganic standards. These segments are:
Lower Yampa, Segments: 3c, 3d, 17a
White River, Segments: 9, 13b
Lower Colorado, Segments: 5, 13b
There are several segments in the Lower Colorado Basin that contain standards based on existing ambient quality. Ambient standards are adopted where natural or irreversible maninduced conditions result in water quality levels higher (i.e. worse) 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 Lower Yampa, Segment 16.
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:
Lower Yampa, Segments: 2, 5, 13a
White River, Segments: 12, 20, 21
Lower Colorado, Segments: 2, 3, 14a
There were several segments where temporary modifications that reflect current ambient conditions were adopted. Temporary modifications were set to expire on 12/31/08. The segments and the constituents are:
Lower Yampa, Segment 16: fecal coliform
White River, Segment 9: selenium
White River, Segment 13b: all numeric standards
Lower Colorado, Segments 4, 13b, and 13c: selenium
Lower Colorado, Segment 13b (Persigo Wash and Little Salt Wash): several parameters
In accordance with the triennial review requirements in the federal Clean Water Act and Colorado Water Quality Control Act, the Commission retains its authority to reexamine and revise temporary modifications, if necessary, based upon new information that it may obtain prior to the December 31, 2008 expiration date, regarding the reason for the temporary modifications.
White River, Segment 13b: This segment is subject to temporary modification for all numeric standards to reflect "current conditions." The temporary modifications reflect uncertainty regarding the numeric standards necessary to protect aquatic life and agricultural uses in Yellow Creek. Shell Frontier Oil will work in coordination with the Division to resolve the uncertainty before the temporary modification expires.
Lower Yampa Segments 3c and 3e: The temporary modifications for lower Yampa Segments 3c and 3e reflect significant uncertainty regarding the appropriate long-term underlying inorganics and metals standards for these segments or portions thereof. This uncertainty stems from a general lack of knowledge regarding existing water quality conditions, potential future uses (for example, the Colowyo Coal Company has expressed its intention to relocate its water supply diversion on Taylor Creek to an upstream location that would be above any existing discharges to the stream) and aquatic biota occurring in these segments. The Colowyo Coal Company will coordinate with the Division and conduct water quality, habitat and aquatic life investigations, before the next review to resolve the noted uncertainty.
With respect to Lower Yampa segments 3c and 3e, although the next triennial review will occur in July 2003, the Commission does not anticipate that sufficient information will have been collected as of that time to justify removal of the temporary modifications. Therefore, the Commission has assigned an expiration date of 12/31/2008 for the temporary modifications for these segments. This date coincides with the next subsequent major review of standards in this basin.
Lower Colorado, segment 13b: Temporary modification of "current conditions" is provided in Segment 13b for Persigo Wash from immediately above the Persigo Wash Wastewater Treatment Plant discharge point to the confluence with the Colorado River and for Little Salt Wash from immediately above the Fruita Wastewater Treatment Plant discharge point to the confluence with the Colorado River. The temporary modification is for ammonia, boron, fecal coliform, cadmium, copper, mercury, silver, nickel, nitrite, and dissolved oxygen and shall expire 12/31/08. The temporary modification is provided to the Cities of Grand Junction and Fruita and others to resolve questions about and the uncertainty of application of the specific standards to the segment and the lower portions of Persigo and Little Salt Washes. The temporary modification provides time for setting appropriate, attainable standards, evaluating the feasibility of discharge point(s) in the wash or moving the discharge points elsewhere, including into the Colorado River, the need for additional treatment processes, if any, for the wastewater treatment plant and the affect of any action on the endangered species. The adoption of the temporary modification recognizes current conditions while providing an opportunity to remove the uncertainty.
The Commission expects that a plan for resolving the uncertainty that is the basis for the temporary modification will be developed, with participation from EPA, the U.S. Fish and Wildlife Service and others, by the time of the November, 2002 "issues formulation hearing" for this basin. Based upon review of that plan at that informational hearing, the Commission can determine whether there is any need for formally considering a change to the duration of this temporary modification in the July, 2003 rulemaking hearing for this basin.
The organic chemical standards were updated to include changes adopted by the Commission in the 2000 revisions to the Basic Standards (see section 31.11 in Regulation No. 31). "Water + Fish" organic chemical 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 chemical 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.
Information was reviewed regarding Aquatic Life Class 2 segments that have fish that are presently being taken for human consumption or have fisheries that would indicate the potential for human consumption. That information showed that one additional segment had the potential for consumption offish. White River, Segment 17 was designated to receive the full protection of numeric Fish Ingestion organic standards.
These segments had the Water Supply classification added to them. The associated water supply standards will now apply to segments:
Lower Yampa, Segment: 3c, 3e
White River, Segments: 9, 21
Lower Colorado, Segments: 4
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 section 31.11). The Commission modified the water supply standards for iron, manganese, and sulfate that are based on secondary drinking water standards (based on aesthetics as opposed to humanhealth 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 section 31.11 : 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 sitespecific rulemaking hearing that such standards are appropriate.
There are two segments in the Lower Colorado River Basin that were not classified for Agricultural use. The Agricultural use classification was adopted for Lower Colorado, Segment 11c. White River segment 16b previously did not have an agriculture use; however, it was combined with segment 16a which had an agriculture use. The new segment 16 has an agriculture use.
Numeric Standards to protect Agricultural Uses were adopted for the following segments:
Lower Yampa, Segments: 3a, 3b, 6, 14, 17b, 20
White River, Segments: 13a, 22
Lower Colorado, Segments: 11b, 11c, 11e, 11g, 13a
The Commission corrected several typographical and spelling errors, clarified segment descriptions and removed "eff 3-2-98:" which refers to the now past effective date for the chronic silver standards.
The following aquatic life classifications were upgraded from class 2 to class 1 based on information presented that showed diverse aquatic communities in these segments.
Lower Yampa, Segments: 5, 12, 17a
In addition. Lower Colorado, Segment 17 was changed from aquatic life class 2 warm to class 1 cold, based on information received about the aquatic community that includes trout species.
Site-specific numeric standards were adopted for the following segments:
Lower Yampa, Segment 3b: Site-specific agricultural standards were adopted to protect livestock watering since Trapper Mining provided evidence that water from this segment is not used for crop irrigation.
White River, Segment 13b: Site-specific agricultural standards were adopted to protect livestock watering and irrigation of pasture for livestock feed since Shell Frontier Oil provided evidence that water from this segment is not used for irrigation of sensitive crops.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-37.17