5 Colo. Code Regs. § 1002-32.50
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, 2014, to determine whether the temporary modification should be modified, eliminated or extended.
Temporary modifications of 36 standards on 30 segments were reviewed. The Basic Standards Statement of Basis for the 2010 hearing records the Commission's intent regarding temporary modifications. (see 31.48 at I.A)
Since temporary modifications have no impact on other aspects of Colorado's water quality management program such as the 303(d) list, the Non-point Source Program or the Total Maximum Daily Load (TMDL) Program, it is fitting that temporary modifications only be used where there are permitted discharges that would face unreasonable consequences in the absence of a temporary modification (e.g., a permit compliance schedule to meet a standard that is significantly uncertain).
Deleted: Temporary modifications were deleted on the following segments because there are no currently identified discharge permits on the segments.
Upper Arkansas segment 2c
Middle Arkansas segments 4b, 5, 10, 12, 14, and 18a
Lower Arkansas segments 4, 9a, 9b, 9c, and 11
No action: The Commission took no action on the temporary modifications on the following segments which are receiving waters for permitted discharges. These temporary modifications will expire 12/31/2013. The basin-wide review hearing is scheduled for June 2013 and it is anticipated that the remaining issues will be resolved in that hearing process.
Upper Arkansas segments 2b, 3, 8a, 8b, and 12a
Middle Arkansas segments 4c, 6,and 9
Fountain Creek segments 1a, 2a, 4, and 6
Lower Arkansas segments 1b, 1c, 5a, 6, and 7
Lower Arkansas River segment 1a: The Commission retained the temporary modifications for selenium and sulfate equal to existing conditions for Lower Arkansas segment 1a and extended the expiration date to June 30, 2016.
As discussed in previous hearings (see 1998 and 2007 Statement of Basis) the selenium and sulfate issues in segment 1a are complicated. Uncertainty regarding the appropriate underlying selenium standard continues with the delay in release of the federal 304(a) draft criteria. In addition, the Commission reaffirms the determination that Pueblo's discharge of intercepted ground water which contains selenium and sulfate results in a reduced load of selenium to the system.
The Commission extended these temporary modifications to allow time for the City of Pueblo to pursue a discharger-specific variance or other permanent solution. The Commission recognizes that further developments before 2016 could complicate development of discharger-specific variances for selenium and sulfate. For example, depending on the criteria EPA develops, discharger-specific variances may not be necessary. In particular, the relationship between selenium and sulfate in EPA's selenium criteria document could substantially affect standards development. If the application of EPA criteria and recalculation procedures result in site-specific standards that are attainable without causing more environmental harm than good, then discharger-specific variances would not be necessary.
The temporary modifications will be reviewed in the 2014 and 2015 annual reviews and can be resolved or extended in those proceedings.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-32.50