5 Colo. Code Regs. § 1002-36.15
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 the 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:
The revisions to the Classifications and Numeric Standards for Rio Grande River Basin (3.6.0) resulting from the November, 1993, rulemaking hearing represent the first comprehensive examination of the basin's water quality since the standards were first adopted in May, 1982. This comprehensive review was facilitated by the basin monitoring program of the Water Quality Control Division, the Rio Grande Basin being the first basin to be studied by the Division. The following is the basis and purpose for the changes made organized according to topics. The specific rationale for each segment change is contained in the Water Quality Control Division's Exhibit 2 introduced at the hearing.
The Basin was previously divided into two sub-basins, the Rio Grande and the Closed Basin. Because of the relatively large size of the Rio Grande sub-basin and the size and number of segments in the Conejos and Alamosa/La Jara sub-basins, the Division recommended creating an Alamosa/La Jara/Conejos sub-basin and renumbering the segments within them. The Commission noted that this recommendation would result in the separation of segment 15a, which is a very large segment representing a diverse geographic area and several different types of streams. The Commission felt that resegmentation of the large sub-basin would result in a more precise application of classifications and be more understandable by the casual reader. Similarly, the Commission considered the consolidation of segments proposed by the Division to be good housekeeping and better reflective of the nature of basin waters. The Commission was supportive of the deletion of the English term "River" when used with Spanish named streams, and consequently revised the title of the regulation to RIO GRANDE BASIN, 3.6.0, making similar changes in the segment descriptions for the Rio Grande and Rio San Antonio.
Alamosa Segments 2 and 3. Based on the evidence presented at the hearing, the Commission has adopted two changes to the definition of these segments of the Alamosa River. One change adopted is the expansion of segment 2 of the Alamosa to include the reach of existing segment 3 between Iron Creek and Alum Creek. Data collected by the USGS in 1993 indicates that the water quality of this reach is more similar to that found in segment 2 than to the water quality of segment 3 and is likely to meet the table value standards applicable to segment 2 at least 85% of the time. The inclusion of this reach in segment 2 will also provide additional protection to a fishery which, according to the Division of Wildlife, the reach currently supports.
The other change adopted by the Commission is the split of existing segment 3 into segments 3a and 3b immediately above the confluence of Wightman Fork. This split is logical given the presence of the Summitville mine site and its loading contribution to new segment 3b via the Wightman Fork. While the existing classifications for segment 3 will be retained in both newly created segments, temporary modifications for segment 3b must be adopted to reflect the segment's conditions while the Summitville site clean up proceeds. In addition, due to the past and ongoing treatment at the Summitville site, the hardness in the two segments is different, further justifying a split of the segment.
As a complement to the resegmentation discussed above, it was necessary to establish several new segments in order to provide complete geographic coverage of the Basin. In addition, the Basin Wide Initiative identified several streams that are sufficiently different with regard to potential uses that they should be identified by their own segment descriptions. They are the mainstem of Cat Creek, the mainstem of the Rio San Antonio from Highway 285 to the Conejos River, and the mainstem of Hot Creek (a tributary to the La Jara Creek). The Division proposed separating the segment descriptions for the Alamosa and Monte Vista National Wildlife refuges because of their geographic separation and because the source of water to each is significantly different. The Commission concluded that all the Division recommendations related to the creation of new segments were justified and were necessary to provide complete geographic coverage of basin streams.
With the adoption of revisions to 3.1.0, Basic Standards for Surface Water, incorporating wetlands into the classification and standards structure it became necessary to reflect those provisions in this first triennial rulemaking since 3.1.0 was revised. The Division proposed adding "wetlands" to every segment description where formerly the description read "tributaries, lakes, and reservoirs". The Division also proposed creating new segments solely for tributary wetlands where the existing "all tributaries" classification and standards were insufficient to protect wetlands. The Commission adopted these Division recommendations because they correctly implemented the recent changes to the Basic Standards. The Commission noted that it was appropriate to consider all tributary wetlands in the flood plain of a mainstem classified segment as having the segment's classifications and standards even though the description did not specifically include the term "wetland".
Several segments within the Rio Grande basin did not have use classifications which met the fishable/swimmable goals of the Clean Water Act. The Commission, Division, and EPA Region VIII have been working on a strategy to address this problem, particularly on streams that have a recreation 2 classification and fecal coliform standards of 2000/100ml. Consistent with the approach recently adopted by the Commission, three segments were proposed for reclassification from recreation 2 to recreation 1. These changes were based on actual use of the segment. A change in the fecal coliform standard from 2000/100ml to 200/100ml was also recommended on recreation 2 segments that do not have point source discharges, or if there are dischargers to the segment, no adverse impact from the more restrictive standard is expected.
The Division also identified several segments where it was appropriate to modify the aquatic life classification. These modifications include adding an aquatic life classification to a segment that formerly had no aquatic life classification, changing the classification from class 2 to class 1, or changing the classification from warm to cold water. In each case, the Division recommended that appropriate numeric standards accompany each change in classification.
The Commission felt that the Division recommendations were appropriate and consistent with the Basic Standards for Surface Water, and consequently, adopted the recommendations.
Human health based organic standards (Basic Standards for Organic Chemicals, 3.1.11 (3) of the Basic Standards and Methodologies) apply to all segments which are classified aquatic life 1 and/or water supply. Human health based organic standards are also appropriate for class 2 aquatic life segments where fishing is a significant activity. The Division recommended that human health based organic standards be adopted for the following class 2 aquatic life segments:
La Jara Creek Segment 12
Conejos River Segment 15, 16
Rio San Antonio Segment 18
The Division testified that although these segments were appropriately classified Class 2 Aquatic Life, there was sufficient evidence that fishing is a significant activity of these segments to warrant the application of the "water and fish" organic standards. The Commission concurred with the Division position and adopted the recommendations by including the notation "water and fish organics" in the Qualifiers column.
Several aquatic life class 2 segments of the Rio Grande Basin lacked numeric standards for parameters contained in Tables II and III of the Basic Standards and Methodologies (3.1.16). These standards, or ambient based standards where appropriate, were recommended for application to all aquatic life class 2 segments which lacked those standards in the previous rule. The Commission agreed with the recommendation and adopted those standards as proposed by the Division.
Several segments in the Rio Grande Basin have not been classified for aquatic life. These include portions of Willow Creek, Kerber Creek, streams in the Summitville area, and tributaries to the Rio Grande in the lower, drier southern portion of the basin. The Division acquired information for this hearing indicating that most of those segments continue to fail to meet the criteria for an aquatic life classification. Exceptions include Cat Creek Hot Creek, lower Rio San Antonio, and wetlands in the lower basin, segments now recommended for an aquatic life classification. The Commission considered the data presented by the Division as the equivalent of a use attainability study for each segment, and, as a consequence, did not adopt the aquatic life classification for the segments listed because the use was currently non-existent and unlikely to be attainable within a twenty-year time frame.
At the hearing, Climax Molybdenum raised an issue regarding the appropriateness of an "agriculture" use classification for Rio Grande segments 7 and 9; Alamosa segments 3, 5, 6, 7 and 20; and Closed Basin segments 7 and 11, based on information introduced into the record indicating that existing agricultural uses may not be in place on these segments. The Commission notes that classifications may be established based on (1) existing uses, (2) adequate quality and reasonably expected future uses, or (3) uses for which water is to become suitable as a goal. All of the segments listed have an existing agricultural use classification, and no change in those classifications was proposed in this hearing. Therefore, the basis for the existing classifications was not specifically reviewed for these segments in this hearing. If a future issue should arise regarding the appropriateness of an agriculture classification for one or more of these segments, the Commission can review the available information to determine whether a classification should be deleted at that time.
The Division presented extensive information on the chemical quality of basin streams gathered during the prior year of intensive basin monitoring or available from earlier monitoring. The net result of that information was a showing that the vast majority of Rio Grande basin streams meet Table Value Standards (TVS) for all parameters. For those segments that were exceptions to the general rule, the Division recommended either ambient based standards, site-specific standards, or temporary modifications with underlying TVS. Ambient standards were recommended for the Alamosa River (iron), and Wightman Fork (cadmium and zinc). Site-specific standards for metals were recommended for portions of willow creek near Creede, and temporary modifications for the Alamosa River below Wightman Fork and Kerber Creek. The Commission concluded that the Division recommendations for revised standards were appropriate and consistent with the Basic Standards, and adopted them as proposed.
Alamosa River Segments 3a and 3b. For the newly created segments 3a and 3b, the Commission has adopted table value standards for all metals except iron, copper and aluminum. Ambient standards for iron were adopted for segments 3a and 3b, based on historic and recent data which indicates the presence of naturally elevated levels of these pollutants. The adopted ambient values for both segments are based on data obtained in segment 3a because the ambient conditions in segments 3b have been impacted by the Summitville site. Under the Basic Standards, the Commission may adopt ambient standards only where the ambient conditions are naturally-occurring or are the result of irreversible human impacts. At this point in time, it is too early to determine whether the Summitville site has irreversibly impacted segment 3b of the Alamosa River. Therefore, the iron ambient standard adopted for segment 3b is the same as applicable to segment 3a.
The Commission has also adopted an ambient standard for copper but only for segment 3b. A chronic, ambient standard for copper for segment 3a would be inappropriate because, given the low hardness of this segment, the chronic, ambient standard based on the 85th percentile of the copper data for segment 3a would exceed the acute table value standard for that parameter. This result is precluded by the Basic Standards. The Commission also adopted a temporary modification to the acute TVS for copper for segment 3b, effective for three years, which is based on preventing acute toxicity to brook trout.
Finally, evidence introduced at the hearing indicates that while no standard for aluminum is currently in place for existing segment 3, aluminum is a substantial problem in that segment. The 1993 USGS data introduced by the Division indicates that nonpoint source contributions of aluminum to segment 3a are extremely elevated during low flow conditions and when pH levels are below 5.0. To reflect these conditions, the Commission has adopted acute and chronic TVS standards for both segments but specified the chronic TVS would not be applicable between October 1 and April 30.
Alamosa River Segments 5 and 8. The noticed proposal recommended ambient standards for iron and zinc for segment 5 of the Alamosa River, based on recent data from that segment. The Division of Wildlife presented evidence which indicates that this segment met table value standards for these parameters in 1987. The evidence also shows that in 1987, there was an abundance of brook trout in the segment. The evidence indicates that the higher levels of zinc and iron and subsequent disappearance of the brook trout population is due to the dumping of waste work into or near the stream by Summitville's activities. Since the higher levels of those parameters are not naturally occurring but human induced, the Division has recommended and the Commission is adopting table value standards for zinc and iron with temporary modifications to reflect the segments' conditions while clean up continues.
The noticed proposal also recommends the adoption of a class 1 aquatic life classification for Segment 8 of the Alamosa. The Division subsequently recommended to withhold upgrading at this time pending the results of additional studies scheduled to be conducted in the reservoir, to determine its suitability for upgrade. Following the Division's recommendation, the Commission is not adopting the class 1 aquatic life classification for segment 8 at this time.
Kerber Creek - Closed Basin Segments 8, 9, and 11. Given the ongoing studies and voluntary clean up plans by ASARCO and the Colorado Department of Health for the Bonanza mining district, the Division and ASARCO jointly requested the Commission to segregate these segments for consideration in a separate rulemaking hearing. A joint stipulation was submitted to the Commission to this effect. The Commission has granted the Division and ASARCO stipulation. A rulemaking hearing to consider these segments of the Closed Basin sub-basin has been scheduled for June of 1994.
PARTIES TO RULEMAKING HEARING NOVEMBER, 1993
5 CCR 1002-36.15