5 Colo. Code Regs. § 1002-42.12
The provisions of C.R.S. 25-8-202(1)(a), (b)(i)(2) and (7); and 25-8-203; and 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
In accordance with the directive issued in the Statement of Basis and Purpose in the May 1991 hearing, the Commission has decided to proceed with classification of the specified areas surrounding 10 of the 20 largest community ground water systems in the state for domestic use-quality and agricultural use-quality, and to assign the ground water standards found in Table 1-4 of the "Basic Standards for Ground Water" to these areas. This action was taken to provide needed water quality protection for public drinking water supplies, it was not intended to impose significant changes or additional restrictions on ground water users.
The Commission determined that the Division's proposal to classify the ground waters underlying the specified areas surrounding 10 of the state's 20 largest public ground water systems for domestic use-quality and agricultural use-quality, and to assign the water quality standards included in Tables 1-4 of the "Basic Standards for Ground Water" 3.11.0 (5 CCR 1002-8) was reasonable and consistent with the Commission's responsibility to protect ground water quality for beneficial use.
Site-Specific classification of the specified areas required information on the wells and the aquifer to develop a computer-generated model that delineates an area around the wells or wellfields. The information needed was furnished by the public water suppliers. The water found in the specified areas most directly influences the drinking water or agricultural wells, and therefore needs to meet the domestic use and/or agricultural use quality standards. This action, in combination with the assignment of the ground water standards, helps to ensure a safe, potable water supply.
The decision to add the agricultural use-quality classification was based on information that irrigation and stock watering wells were located and permitted within the specified areas. Therefore, it seemed important to protect the agricultural use through application of the agricultural table values as well as with those for potable use protection. It is anticipated that this action will provide protection of the ground water source, but will not alter or change the regulatory requirements of the Safe Drinking Water Act (SDWA).
As originally formulated, the ground water underlying the state's 20 largest community ground water systems was targeted for classification and standards setting. This number had to be reduced to 15 due to difficulties in assembling the data needed to generate the delineated areas with the degree of confidence desired. The number was reduced to 14 when the Commission and Division decided to withhold South Adams County Water and Sanitation District from consideration until a more thorough evaluation could be done of the implications of including the Rocky Mountain Arsenal in the specified area to be classified to protect the District's drinking water source. Reconsideration of South Adams County W&SD will take place once this evaluation is completed.
The number was further reduced to 10 by the Commission in accordance with a request during the rulemaking hearing from the cities of Brighten, Fort Morgan, Fort Lupton, and Sterling in order to give those cities time to develop more data and obtain more support for the classification. Accordingly, the hearing date for those cities will be October 1994. The Commission anticipates publishing the Notice as the current Division proposal unless it is convinced otherwise in the interim.
Of the 14 systems proposed for classification and assignment of the table value standards, the largest, the City of Brighton and Willows Water District each serve approximately 14,000 residents, the smallest, Stratmoor Hills, serves 5,000. The total number served by the 14 systems is 128,610 people. After the deletion of the four northern cities, the total number served by the 10 remaining systems is 90,160 people. It should be noted that Cherokee Water and Sanitation District in eastern El Paso County numbers among the 20 largest systems but was omitted from the initial proposal because it is located in the Upper Black Squirrel Aquifer which was classified in September, 1991.
The specified areas to be protected were determined through the use of a modular, semi-analytical ground water flow model developed for the U.S. EPA Office of Ground Water Protection for use in the wellhead protection program. Referred to as the WHPA (Wellhead Protection Area) 2.0 model, its principal application has been to delineate wellhead protection areas around public ground water systems. The term wellhead protection area refers to the surface and subsurface area surrounding a water well or wellfield, supplying a public water system, through which contaminants are reasonably likely to more toward and reach the well or wellfield.
The decision to use the wellhead protection concept was influenced by the fact that it is relatively easy to employ if necessary data elements are available; and the resulting delineated areas are accurate indicators of the surface and subsurface areas that must be addressed if the water source is to be protected. These specified areas are an approximation using the semi-analytical flow model to define the ground water area to be protected.
The introduction of this proposal and the data gathering efforts that support it fulfill the Commission's goal to adopt water quality classifications and standards for ground water in the vicinity of public drinking water supplies. This is viewed as an important step in protecting these drinking water supplies, and will be for the remaining ten public water systems and for others in the future.
It should be emphasized that these use classifications and standards assignments do not preclude holding public hearings to set site-specific classifications and numerical standards as the need for such arises. If new data is developed which points to a need to reconfigure any of the specified areas adopted herein, requests for site-specific hearings will, of course, be considered by the Commission.
The information generated in the course of developing this proposal will become part of the ground water quality data base. Efforts continue to verify and integrate the data collected and to use it in developing a comprehensive state ground water protection strategy. In addition, the information on wells and the potential contaminant threats to ground water quality will be evaluated as part of the overall wellhead protection strategy. A concerted effort will be made to work with local public water suppliers to proceed with wellhead protection measures as a means of providing long-term protection for their wells.
In the course of the hearing, the Division did alter, and in some cases, expanded, the shape of the specified areas to accommodate additional well data and water rights information from the affected suppliers. Although several parties supported such modifications, others questioned whether the notice was broad enough to encompass expansion of the specified areas. The purpose of this regulation as stated in the notice is to protect public drinking water supplies of certain identified public water systems from contamination. The Commission believes it is within the scope of the notice therefore to expand the boundaries of the specified areas to include all public drinking water wells and the areas that surround these wells through which contaminants are reasonably likely to move toward and reach such well or wellfield. The Commission finds that there was adequate legal basis for those changes and believes that this rule, as adopted, is consistent with the subject matter as set forth in the notice, including the narrative portion of the notice.
The water quality data submitted by the Division and parties indicated that all but one of the subject systems is meeting drinking water standards at the tap with chlorination as the sole method of treatment. This evidence was sufficient to demonstrate that the water quality is adequate to meet the majority of primary and secondary drinking water standards as well as agricultural table value standards.
In promulgating this rule, the Commission recognizes that the current ambient water quality may not necessarily meet the table value standards at every point in the classified aquifers throughout the specified areas. However, given the Commission's statutory charge to protect, maintain and improve the quality to state waters, (see 25-8-101 et. seq.) and the evidence of use and potential use and the utilization of the model and Division mapping, including the five year time of travel factor applied, the Commission believes it is appropriate to proceed at this time to protect the identified uses by classifying and establishing table value standards.
IMPLEMENTATION
The Commission has authority to classify waters of the state and to promulgate water quality standards to protect those classified uses Under SB 89-181, the various implementing agencies will carry out the impact of this regulation. The WQCD has provided lists of various agencies which could use these regulations to implement their own programs.
During the hearing the Commission received testimony on how the Hazardous Materials and Waste Management Division may use this regulation as the basis for overly stringent clean-up requirements at the Lowry Superfund site and the Eagle Picher/Schlage Lock clean-up sites which it regulates that are located within or near specified areas included in this regulation. Although the Commission is concerned about how implementing agencies will use its regulations, the Commission points out that it is obligated to promulgate regulations that ensure that existing and potential uses of state waters are protected. Evidence in the record before the Commission indicates that the specified areas identified in this regulation all contain sources or potential sources of drinking water which, therefore, must be protected from contamination at appropriate levels. The Commission also received evidence that the Hazardous Materials and Waste Management Division has the authority to select more stringent clean-up standards than the standards adopted by the commission, thus any less stringent standard adopted by the Commission would likely not provide any relief to such affected dischargers. The Commission understands that the classifications and standards it selects for specified areas may impact clean-up requirements at sites regulated by the Hazardous Materials and Waste Management Division, nevertheless it believes that there is sufficient flexibility in setting points of compliance to accommodate specific implementation concerns.
At such time as any of the implementing agencies move forward with their own proposals, the Commission anticipates that parties to this rulemaking and other interested persons will have full opportunity to participate in the formulation of such implementation, and no waiver of such right shall be inferred from the adoption of this rule. The Commission also acknowledges that the setting of points of compliance during permitting should be done with flexibility that recognizes that recharge zones can be within the capture zone or specified area, and can be derived from more detailed modeling, since such modeling is an iterative process.
The Commission would note that the EPA model used to delineate the capture zones surrounding the public water supply wells or wellfields was developed to identify wellhead protection areas. Such areas are defined by federal statute as "the surface and subsurface area surrounding a water well or wellfield supplying a public water system, through which contaminants are reasonably likely to move toward and reach such water well or wellfield". In this rulemaking, the Commission is only classifying waters underlying the areas generated by the model and Division mapping.
The Commission does not intend to pre-judge whether any particular activity generates pollutants or contaminants which could impact ground water without adequate preventative methods. The Commission does however recognize that the adopted specified areas do represent the areas through which contaminants are reasonably likely to move toward and reach the subject wells.
The Commission also recognizes that these classifications are not intended to confer upon any public water supplier the right to exercise authority over the activities, uses or operations of any other public water supplier, except as may be otherwise permitted by law.
EAST CHERRY CREEK VALLEY WATER AND SANITATION DISTRICT AND WILLOWS AND CENTENNIAL GROUND WATER CLASSIFICATION AREA
The boundaries of these specified areas have been based on the existing uses and reasonably expected future uses of the groundwater. The reasonably expected future uses have been based on existing court decrees that authorize the withdrawal of the groundwater, the water providers' testimony that such groundwater will be withdrawn for such uses, and utilization of the Division's model and mapping methodology. The quality of the classified groundwater generally meets the table value numbers for the classified uses although there is evidence in the record demonstrating that not all of the table value numbers are being met at all points throughout the specified area. It is the Commission's intention that the above assumptions and evidence be taken into account when implementing any of the adopted classifications and standards.
WATER RIGHTS
Numerous parties expressed concern that implementation and enforcement of the proposed ground water classifications and standards have the potential to cause material injury to water rights. Like the surface water standards, these standards are not self-implementing. In the absence of separate implementing authority, and the exercise thereof, the adopted standards are not intended to have a regulatory impact upon the exercise of water rights, including, but not limited to, the withdrawal and use of surface water or ground water for irrigation or stock watering, the use of surface water or ground water in recharge, augmentation, substitute supply, or exchange plans, and the diversion, carriage, storage, or release from storage of surface water or ground water. Naturally, the implementation and enforcement of these standards must be in strict compliance with C.R.S. 25-8-104(1). The Commission specifically acknowledges that at such time as proposals or regulations are advanced to implement these standards, those with an interest in water rights shall have the opportunity to contest such proposals or regulations, and no waiver of such right shall be inferred from the adoption of these standards.
PARTIES TO THE APRIL 5, 1993 RULEMAKING HEARING FOR CONFINED AND UNCONFINED GROUND WATER
5 CCR 1002-42.12