5 Colo. Code Regs. § 1002-38.94
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, 2018, to determine whether the temporary modifications should be modified, eliminated or extended.
Current temporary modifications of standards on three segments were reviewed.
No action: The commission took no action on the temporary modifications on the following segments.
Upper South Platte Segment 3: temporary modification of the ammonia standards (expire 12/31/2017) below the Florissant Waste Water Treatment Facility. The Town of Florissant obtained funding to upgrade its facility and a progress report indicated the facility is on track to comply with ammonia effluent limits.
Upper South Platte Segment 10a: temporary modification of the copper standards (expire 12/31/2018) below the Plum Creek Water Reclamation facility outfall. PCWRA continues to make progress on data collection for a Biotic Ligand Model (BLM) based site specific standard.
Clear Creek Segment 13b: temporary modification of the cadmium standard (expire 12/31/2018). Black Hawk/Central City Sanitation District continues to make progress on resolving the uncertainty.
New Temporary Modifications
St Vrain Segments 6 and 7: temporary modifications of the total recoverable and dissolved iron standards and the dissolved manganese standard were added to these segments. Raytheon presented evidence regarding uncertainty of these standards and a compliance problem. These temporary modifications will expire on 12/31/2020 and will be reviewed beginning in 2018.
New Temporary Modifications of the Arsenic Standard:
Consistent with the actions taken in 2013, the commission adopted a temporary modification of the arsenic standard on segments on the following list, with an expiration date of 12/31/2021. At the April 8, 2013 rulemaking, the commission heard testimony that concurred with the finding from a December 13, 2011 hearing that an initial reasonable lower limit of treatment technology for arsenic is 3.0 µg/L, pending further investigation by the division, dischargers and stakeholders. The temporary modification was established by the commission to allow for a temporarily less stringent application of the chronic arsenic standard in control requirements for both existing discharges and new or increased discharges.
Upper South Platte Segment 16b
Upper South Platte Segment 19
Cherry Creek Segment 2
Clear Creek Segment 2b
Clear Creek Segment 6
Clear Creek Segment 12b
Big Dry Creek Segment 2
Boulder Creek Segment 17
St Vrain Segment 4a
St Vrain Segment 12
Middle South Platte Segment 7
Big Thompson Segment 14
Big Thompson Segment 16
Big Thompson Segment 17
Cache la Poudre Segment 7
Republican Segment 1
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-38.94