5 Colo. Code Regs. § 1002-42.17
The provisions of C.R.S. 25-8-202; 25-8-203; 25-8-204 provide the specific statutory authority for adoption of these regulatory provisions. The Commission has also adopted, in compliance with C.R.S. 24-4-103(4), the following statement of basis and purpose.
BASIS AND PURPOSE
Initially, this hearing was to consider classifications and standards for the ground water underlying the wellfields of the Cottonwood and Parker Water and Sanitation Districts. These two systems were part of a group classified in June, 1994, however they were removed from consideration at the request of the Lincoln Park Metropolitan District for reconsideration in December, 1995 pending conclusion of a ground water study. The study in question is being sponsored by the Cherry Creek Basin Water Quality Authority and is designed to develop baseline water quality data in the upper Cherry Creek Basin (from Castlewood Canyon to Cherry Creek Reservoir). The study began in August, 1994, and was to conclude in July, 1995. Due to a myriad of circumstances, the Commission learned in July, 1995, that an additional year would be needed to complete the study and analyze the results.
In negotiations with the Water Quality Control Division, which had advanced the original classification proposal for the two public water systems, the proponents for postponing the December, 1995 hearing until the study could be completed, agreed instead to support going forward with the hearing provided the standards were applied on an interim basis until the study is completed. At that time the Commission will re-consider the standards, based on the outcomes of the study, and use this information in determining the adoption of permanent standards. The Division asked that specific constituents be added to the study for the final year, these included gross alpha, metals and e. coli bacteria. The addition of these constituents and the sampling schedule for them was to be approved by the Cherry Creek Basin Water Quality Authority.
It was also agreed that the area considered for classification in the December, 1995 hearing would expand from the wellfields of the two public water systems (Cottonwood and Parker), as originally proposed, to include the alluvial aquifers and their tributaries, and the Denver Basin aquifers located in the upper Cherry Creek Basin. This is an area, as illustrated in Figure 39, that encompasses portions of El Paso, Douglas and Arapahoe counties. The Commission determined that site-specific classification was important to ensure the protection and preservation of the ground water in an area undergoing abnormally high residential and commercial development.
The action requested of the Commission was to classify the area specified in Figure 39 for "domestic use-quality", and "agricultural use-quality." The standards that are appropriate to protect these two use classifications are those found in Tables 1 through 4 of "The Basic Standards for Ground Water 3.11.0 (5 CCR 1002-8).
The Commission decided that it was appropriate to adopt the Table Value standards as interim standards in view of the ongoing study in a portion of the specified area which could result in proposed ambient-based standards in a subsequent rulemaking. The Commission noted that it expected these interim standards to function as the foundation for any regulatory decisions that might be made affecting ground water in the specified area in that interim between this action and any future rulemakings on the permanent adoption of standards.
The Commission also adopted these interim standards as applicable to all ground waters underlying the specified area proposed in the public notice, alluvial ground waters as well as those contained in the Denver basin aquifers.
Written testimony submitted by one group of parties asserted that these classifications and standards may cause significant additional investment in treatment plants and monitoring requirements, and that irrigation use could be restricted if the proposed classifications and standards were implemented. The Division and others responded that such effects were highly unlikely since there already were reasonable limits in place in the discharge permits for existing dischargers based upon the narrative standard (Tables 1-4, Basic Standards, as criteria), and that statutory prohibitions against injuring water rights via water quality regulation would fully protect against the fear that irrigation with raw water might be restricted in some manner. At the hearing, the parties that raised these issues indicated that their concerns had been addressed.
Finally, a party requested clarification on whether the interim organic standards in Table A of the Basic Standards for Ground Water, 3.11.5 (5 CCR 1002-8), continue to apply to the specified areas classified in this hearing. Under that section, the organic standards in Table A are in effect statewide unless replaced by site-specific standards for the listed organics. The standards adopted by the Commission in this hearing do not include site-specific standards for organics. Therefore, Table A continues to apply to the specified areas.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-42.17