Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-35 - REGULATION NO. 35 - CLASSIFICATIONS AND NUMERIC STANDARDS FOR GUNNISON AND LOWER DOLORES RIVER BASINS
Section 5 CCR 1002-35.42 - STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; DECEMBER 14, 2015 RULEMAKING; FINAL ACTION JANUARY 11, 2016; EFFECTIVE DATE JUNE 30, 2016

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 scheduled to expire before December 31, 2017, to determine whether the temporary modification should be modified, eliminated or extended. Temporary modifications of standards on four segments were reviewed.

The Commission took no action on the temporary modifications on the following segments.

Uncompahgre segment 4b: Temporary modification of the selenium standards. The Commission took no action on the selenium temporary modifications on Uncompahgre segment 4b. The Town of Olathe did not participate in this rulemaking but the temporary modification will be reviewed in December 2016.

The Commission deleted tine temporary modification on tine following segment.

Upper Gunnison River segment 20: Temporary modification of the acute and chronic uranium standards. These temporary modifications expired on 6/30/2015. The Commission authorized deletion of the temporary modification from the tables.

The Commission extended the temporary modifications on the following segments.

Lower Gunnison segment 2: Temporary modification of the selenium standard. The Commission extended the temporary modification for chronic selenium with a narrative value of "current condition" to December 31, 2022 to coincide with the next basin review. The City of Delta wastewater treatment facility is currently discharging selenium at an average concentration of 8.45 ug/L and is addressing the inflow and infiltration into their collection system that is the cause of elevated selenium in their effluent. The City of Delta recently purchased a new wheeled collection system camera and has identified, with video and sampling a few sources of I & I (Inflow and Infiltration) and funds up to $150,000 for this year have been allocated for pipe replacement. There is also still significant uncertainty concerning the underlying selenium standard. Time is needed to wait for the EPA's new selenium criteria and implementation guidance, and to determine an appropriate underlying selenium standard for Lower Gunnison segment 2. The progress on resolving the uncertainty with the selenium standard will be reviewed at the annual temporary modification hearing December 2020.

Upper Gunnison segment 12: Temporary modification of metals standards. The Commission extended the existing temporary modifications for cadmium, copper and zinc, which were adopted for segment 12 during the September 2012 rulemaking; these temporary modifications are now scheduled to expire on December 31, 2017. This extension will allow sufficient time to resolve the existing uncertainty regarding metals loading sources to segment 12 and develop site-specific standards. It will also reconcile the expiration date for the temporary modifications with the projected effective date for revised water quality standards adopted during the June 2017 Regulation #35 basin hearing. U.S. Energy presented evidence that progress is being made on implementation of the Study Plan to Evaluate Metals Loading in the Coal Creek Watershed in the Vicinity of the Keystone Mine (the "Study Plan"). The Study Plan, as approved by the Commission, is intended to identify and quantify sources of cadmium, copper and zinc loading that may be affecting water quality in segment 12, including groundwater down gradient of the flooded Keystone Mine workings. To address concerns regarding the groundwater portion of the study, U.S. Energy completed a longitudinal sampling event in November 2015. U.S. Energy identified activities it plans to complete over the next eighteen months to be ready to develop and propose site-specific water quality standards in June 2017, which includes continued data collection (if needed) and evaluation, report preparation, site-specific standards proposal development, and meetings with the agencies and stakeholders. The surface water data collected as part of the Study Plan and additional groundwater data as required by the groundwater portion of the plan will be used by U.S. Energy to develop site-specific standards for segment 12, if appropriate. Water quality improvements and seasonal variation evident from the long-term water quality data collection effort in segment 12 will be evaluated throughout the remainder of the temporary modifications during the development and consideration of site-specific standards. These temporary modifications will be reviewed again at the annual temporary modifications hearing in December 2016.

PARTIES TO THE RULEMAKING HEARING