5 Colo. Code Regs. § 1002-32.35
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
Water Supply Standards: The Commission modified water supply standards to conform with the classification changes made in the July 2002 Rulemaking Hearing for Upper Arkansas segment 20 and Fountain Creek segment 7a. The Commission also modified other water supply criteria, in Upper Arkansas segment 2a, that were inadvertently missed in the July 2002 Hearing.
General cleanup: The Commission adopted Cl2 (ch)=0.011 to Lower Arkansas segment 3a and Lower Arkansas segment 4. These criteria were missing.
Site Specific Issues:
Lower Arkansas segment 1a : Lower Arkansas Segment 1a currently has temporary modifications for selenium and sulfate that are based on existing water quality. In the 2002 RMH, only selenium was adopted based on uncertainty despite the fact that the source of both of these parameters were shown to be of the same source and to be occurring for natural reasons as proposed by the City of Pueblo in the 1998 rulemaking hearing. The Commission adopted the sulfate temporary modification based on uncertainty to be consistent with the selenium temporary modification.
Lower Arkansas segment 2b: The Commission subdivided Segment 2 of the Lower Arkansas River into 2 segments placing King Arroyo into Segment 2b.
The City of La Junta expressed concerns about the application of numeric agricultural standards during the triennial review in July, 2002; but could not object, having certain knowledge that livestock drink from the Arroyo. However, the City did not realize that a separate set of standards could be established for livestock watering when crop irrigation did not take place. The urgency for a site-specific review related to the timing of the City's NPDES permit expiration and renewal process in 2003. The City's permit (effective January, 1999) had limits protective of the Lower Arkansas River based on the stream standards for Segment 1b. The City's permit was also based on King Arroyo standards if those standards were more stringent. The City believed that application of crop-irrigation standards on King Arroyo had high potential for requiring significant additional wastewater treatment for a non-existent use. Nothing in this proposal was intended to change the application of Lower Arkansas River, Segment 1b in the City's discharge permit nor to provide relief to the City for meeting any other standards based on established uses. The application of livestock-watering-only standards on King Arroyo provided sufficient protection for its established uses without unnecessarily causing more stringent limitations in the City's permit.
Since there are water bodies within segment 2 used for crop irrigation, King Arroyo is not one of them. The Commission has left those waterbodies in segment 2a and created a new segment 2b for King Arroyo to classify this segment as Agricultural Use - Livestock Water only. District 17 Water Commissioner, Don Taylor, provided a statement to this effect.
Lower Arkansas Segments 3b and 3c: The Commission determined that certain tributaries in Segment 3a-Frio Canyon Creek, Borrego Canyon Creek, Munoz Canyon Creek, Williams Canyon Creek, and Castro Canyon Creek, including all tributaries, from their sources to their confluences with the Apishapa River - were not in the appropriate segment. Specifically, the Commission determined that the use, physical characteristics and water quality characteristics of these tributaries are significantly different from those of the mainstem of the Apishapa River. As a result, the Commission moved these tributaries to Segment 3b 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 and Gulnare, Colorado. Additionally, the Commission determined that Jarosa Canyon Creek and Rito Seco (a tributary to Jarosa Canyon Creek) did not have the same use, physical characteristics and water quality characteristics as the mainstem of the Apishapa in Segment 3a or the dry tributaries in Segment 3b. Therefore, the Commission created a new segment, Segment 3c, to contain Jarosa Canyon Creek, including all tributaries, from the source to the confluence with the Apishapa River. The Commission assigned to Segment 3c the classifications of aquatic life cold class 2, water supply, recreation 1a and agriculture and applied appropriate standards.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-32.35