Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-42 - REGULATION NO. 42 - SITE-SPECIFIC WATER QUALITY CLASSIFICATIONS AND STANDARDS FOR GROUND WATER
Section 5 CCR 1002-42.29 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY, AND PURPOSE: SEPTEMBER 9, 2002 HEARING ON SITE-SPECIFIC GROUND WATER CLASSIFICATION AND STANDARDS FOR THE GROUND WATER in ONE SPECIFIED AREA OF BACA COUNTY
Current through Register Vol. 47, No. 5, March 10, 2024
SPECIFIC STATUTORY AUTHORITY
The provisions of C.R.S. 25-8-202; 25-8-203; and 25-8-204 provide the specific statutory authority for adoption of these regulatory provisions. The Commission has adopted in compliance with C.R.S. 24-4-103(4) the following statement of basis and purpose.
STATEMENT OF BASIS AND PURPOSE
Background
A.1 Hydrogeologic Units
As a result of this hearing, the Commission applied the classification of limited use and quality to the ground water contained within the following specified area:
Baca County (Figure 51) The Pennsylvanian aged Lansing Formation within a specified area of Baca County, Colorado in which extensive oil and natural gas exploration and development have occurred. The specified area includes approximately 14 square miles in Baca County, Colorado.
A.2 Aquifer Exemption Requirements
The adoption of this Limited Use and Quality classification by the Commission does not preclude the need for obtaining an aquifer exemption under the Underground Injection Control (UIC) program, if future applicants wish to inject fluids into portions of the subject formations within each specified area for which an aquifer exemption would be needed. That is, the adoption of this classification does not preclude the need for compliance with the specific requirements of the UIC program.
A.3 Site-Specific Classifications
Site-specific classification of ground water begins with the identification of the use of the water within the specified area as follows:
Baca County (Figure 51) The ground water in the Pennsylvanian aged Lansing Formation is co-produced with oil and gas and is considered a waste. Within the specified area, ground water in the Lansing Formation is not currently used nor can it reasonably be expected to be used in the future for domestic or agricultural purposes. The ground water is not in communication with any surface water bodies within the specified area so that the water quality standards of any classified surface water bodies are not affected by this ground water. More specific evidence of the limited use and quality of this ground water follows:
Within the specified area there are approximately 25 water wells permitted with the Office of the State Engineer. Nine are shallow stock watering wells, ten are shallow ground water wells installed by the Forest Service, and six are active industrial water supply wells. The Division of Water Resources data indicates that there are no public water systems, or domestic, agricultural, commercial water wells completed in the Lansing Formation within the specified area.
The Lansing Formation contains or has contained naturally occurring accumulations of crude oil and natural gas, in addition to ground water in this specified area. These oil and gas resources have been developed and produced since 1983.
Within the specified area approximately 56 oil and gas wells or tests have been drilled to or completed in the Lansing Formation.
Within the specified area the Colorado Oil and Gas Conservation Commission (COGCC) has not granted any aquifer exemptions for UIC projects under Rule 324(B) of the Rules and Regulations, Rules of Practice and Procedure (2 CCR 404-1), pursuant to the Colorado Oil and Gas Conservation Act, Title 60, Article 34, C.R.S. (1982). Three enhanced oil production injection projects have been permitted within the specified area; however, these did not require aquifer exemptions, because the total dissolved solids (TDS) concentrations of the injection zones exceed 10,000 milligrams per liter (mg/l). These three injection projects contain a total of approximately fourteen injection wells completed in the Lansing Formation.
Within the specified area the Lansing Formation lies between 3,903 to 4,088 feet below the ground surface (fbgs).
Based on information available to the COGCC, within the specified area the TDS concentration of the Lansing Formation ranges from 89,575mg/L to 105,953mg/L The average TDS is 97,764mg/L.
Hydrogeologic data including produced water quality and depths of the Lansing Formation and other COGCC data indicate that the ground water in this formation meets the criteria in Regulation 41 for classification as "Limited Use and Quality" . The Commission, therefore, concluded that the application of the "Limited Use and Quality" classification to the ground water within the Lansing Formation in the specified area is appropriate. This classification and the application of site-specific standards for organic chemicals assure consistency between implementation of the UIC Program requirements and WQCC Standards and Classification.
B. Site-Specific Numerical Standards
Consistent with the "Limited Use and Quality" classification, the ground water quality standards in Tables 1 through 4 of the Basic Standards for Ground Water, 41.0 will not apply within the specified area. Additionally, the ground water organic chemical standards included in Table A of Section 41.5.C.3)of the Basic Standards for Ground Water (5 CCR 1002-41) for benzene, toluene, ethylbenzene, xylenes, and benzo(a)pyrene will not apply to certain oil and gas producing formations within the specified areas. However, to provide some protection of the potential future use of water resources in the specified area, the Commission's action provides that the statewide standard for radionuclides, as well as the statewide organic chemical standards (other than those for benzene, toluene, ethylbenzene, xylenes, and benzo(a) pyrene) will continue to apply to this ground water.
C. Other Revisions
The table and map in section 42.3 , "Index of Classified Areas: has been updated to reflect all current site-specific classifications and standards. In addition, references throughout the regulation to "larger scale maps available in the Commission Office" have been deleted. These anticipated maps have not been completed, and the Commission has determined that they are not necessary at this time. A quality control check indicated that one of the specified areas on Figure 49A had an incorrect outline and has been replaced with a new Figure 49A.
PARTY STATUS/MAILING LIST STATUS FOR SEPTEMBER 2002 RULEMAKING HEARING
