Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-33 - REGULATION NO. 33 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR UPPER COLORADO RIVER BASIN AND NORTH PLATTE RIVER (PLANNING REGION 12)
Section 5 CCR 1002-33.47 - STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER 2010 RULEMAKING REGARDING TEMPORARY MODIFICATIONS FINAL ACTION JANUARY 10, 2011; EFFECTIVE DATE JUNE 30, 2011
Current through Register Vol. 47, No. 5, March 10, 2024
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
Pursuant to the requirements in the Basic Standards (at 31.7(3)), the Commission reviewed the status of temporary modifications to determine whether the temporary modification should be modified, eliminated or extended.
Total Recoverable Iron
A. Dry Creek, Yampa River segment 13d
Seneca Coal Company proposed revisions to Yampa segment 13d. Based on information on the record that characterized the pre-mining condition, the Commission adopted ambient-based iron standards. The chronic ambient-based standard for Dry Creek was calculated considering pre-mining data collected by Seneca Coal Company from three available sites in the segment (WSH7, WSHF1, and WSD5). The Commission removed the temporary modification for iron for segment 13d and adopted a new seasonal ambient-based chronic standard for iron for segment 13d as follows:
Mar - Apr = 3040(Trec);
May - Feb = 1110(Trec)
In order to assure that the same methodology is used when assessing attainment of these standards in the future, Section 33.6 was added to the regulation to record the locations that are to be used. Subsection 33.6 establishes the locations for Dry Creek. Approximately equal datasets from each of these sites is to be aggregated:
* Seneca II-W Stream Site 7 on Hubberson Gulch (WSH7): located in the middle reaches of Hubberson Gulch
* Seneca II-W Flume Site 1 on Hubberson Gulch (WSHF1): located on Hubberson Gulch just upstream of its confluence with Dry Creek
* Seneca II-W Stream Site 5 on Dry Creek (WSD5): located in the middle reaches of Dry Creek
B. Sage and Grassy Creeks, Yampa River segment 13e
Given the presence of two individual creeks in segment 13e, with different characteristics, the Commission took separate actions on each creek.
Sage Creek: Seneca Coal Company proposed revisions to Yampa segment 13e. Based on information on the record that characterized the pre-mining condition, the Commission bifurcated Sage Creek and adopted ambient-based iron standards for upper portion, with a dividing line at the west border of Section 18, T5N, R87W. The chronic iron ambient-based standard for upper Sage Creek was calculated to be 1250 ug/L(Trec). The iron standard for the lower portion remains 1000 ug/L (Trec).
In order to assure that the same methodology is used when assessing attainment of these standards in the future, Section 33.6 was added to the regulation to record the locations that are to be used. Subsection 33.6 establishes the assessment location for upper Sage Creek.
* Yoast Stream Site 2 on Sage Creek (YSS2): located upstream of the west border of Section 18, T5N, R87W
Grassy Creek: Seneca also proposed ambient-based iron standards for Grassy Creek. The upper portion of this area was mined in the 1970's by the Rockcastle Coal Company (Grassy Gap Mine), which obtained bond release and terminated its NPDES permit in 1993. Seneca began its mining operation in the upper portion of the basin in 1998 and the site is currently in the reclamation process. Seneca proposed that the Commission establish ambient-based iron standards based on 1993-1998 water quality data. The Commission determined that Seneca's evidence was insufficient to characterize natural or irreversible man-induced conditions for Grassy Creek. As a result, the Commission declined to adopt ambient-based iron standards, but extended the temporary modification for iron to 12/31/2012. The Commission will consider Seneca's plan to eliminate the need for a temporary modification at the December 2011 temporary modification hearing.
PARTIES TO THE RULEMAKING HEARING
