5 Colo. Code Regs. § 1002-42.30
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.
BASIS AND PURPOSE
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:
Cheyenne and Kit Carson Counties (Figures 52A and 52B) The Pennsylvanian aged Morrow Formation within specified areas of Cheyenne and Kit Carson Counties, Colorado in which extensive oil and natural gas exploration and development have occurred. The specified area includes approximately 90 square miles in Cheyenne and Kit Carson Counties, Colorado.
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.
Site-specific classification of ground water begins with the identification of the use of the water within the specified area as follows:
Cheyenne and Kit Carson Counties (Figures 52A and 52B) The ground water in the Pennsylvanian aged Morrow Formation is co-produced with oil and gas and is considered a waste. Within the specified area, ground water in the Morrow 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 59 water wells permitted with the Office of the State Engineer. The Division of Water Resources data indicates that there are no public water systems, or domestic, agricultural, commercial water wells completed in the Morrow Formation within the specified area.
The Morrow 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 1979.
Within the specified area approximately 374 oil and gas wells or tests have been drilled to or completed in the Morrow 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). Eight 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 eight injection projects contain a total of approximately twenty-three injection wells completed in the Morrow Formation. The Second Wind Field has two gas injection wells; Frontera Field has three gas injection wells; Arapahoe Field has two water injection wells and three gas injection wells; Arapahoe NW Field has one water injection well and one gas injection well; Mount Pearl Field has one water injection well and five gas injection wells; Sorrento Field has one gas injection well; Bledsoe Ranch Field has one water injection well and one gas injection well; Speaker Field has two gas injection wells.
Within the specified area the Morrow Formation lies between 5,088 to 6,531 feet below the ground surface (fbgs). The Second Wind Field ranges from 5,119 fbgs to 5,150 fbgs; Frontera Field ranges from 5,117 fbgs to 5,179 fbgs; Arapahoe Field ranges from 5,088 fbgs to 5,249 fbgs; Arapahoe NW Field ranges from 5,190 fbgs to 5,320 fbgs; Mount Pearl Field ranges from 5,321 fbgs to 5,488 fbgs; Sorrento Field ranges from 5,440 fbgs to 5,478 fbgs; Bledsoe Ranch Field ranges from 6,525 fbgs to 6,531 fbgs; Speaker Field ranges from 6,374 fbgs to 6,386 fbgs.
Based on information available to the COGCC, within the specified area the average TDS concentration of I the Morrow Formation ranges from 39,943mg/L to 225,730mg/L with an average of 39,943 mg/l in the I Second Wind Field; an average of 71,355 mg/I in Frontera Field; an average of 56,693 mg/l in Arapahoe Field; an average of 56,261 mg/l in Arapahoe NW Field; an average of 225,730 mg/l in Mount Pearl Field; an I average of 142,102 mg/l in Sorrento Field; an average of 52,167 mg/l in Bledsoe Ranch Field; an average of 127,662 mg/l in Speaker Field.
Hydro geologic data including produced water quality and depths of the Morrow 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 Morrow 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.
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.
The table and map in section 42.3 "Index of Classified Areas" and "Index Map" have been undated to reflect the new site-specific classifications and standards that were adopted in this rulemaking hearing.
PARTY STATUS/MAILING LIST STATUS FOR DECEMBER, 2003 RULEMAKING HEARING
5 CCR 1002-42.30