37.21	STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER 2006 RULEMAKING REGARDING TEMPORARY MODIFICATIONS; ADOPTED JANUARY 8, 2007; EFFECTIVE MARCH 4, 2007
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
The Commission recently restructured section 31.7(4) and established an annual rulemaking hearing to review temporary modifications (regardless of the basis) that are due to expire in the two years following the rulemaking hearing.  In this hearing, the Commission considered evidence as discussed in subsections 31.7(3) (b) and (c) to determine whether the temporary modification should be modified, eliminated or extended.
The Commission deleted the temporary modifications for the following segments thereby allowing the underlying standards to go into effect:
Lower Yampa segment 3b:  Se(ac/ch) existing quality for Johnson Gulch from the confluence of Johnson Gulch and Pyeatt Gulch to the confluence with the Yampa River
Lower Yampa segment 3c:  inorganics and metals, existing quality
Lower Yampa segment 3e:  inorganics and metals, existing quality
Lower Yampa segment 16:  f. coli =275/100 ml
White River segment 9b: Se(ch) = existing ambient quality 
Lower Colorado segment 4a:  Se(ch) = existing ambient quality 
Lower Colorado segment 13c:  Se(ch) = existing ambient quality 
Because parties are working to resolve uncertainty and are on schedule to address these segments at the regularly scheduled basin-wide rulemaking (June 2008), the Commission took no action on the temporary modifications for the following segments, leaving their expiration dates unchanged:
White River segment 13b:  all numeric standards = current conditions 
Lower Colorado segment 13b:  Se(ch) = existing ambient quality; Persigo Wash from Grand Junction discharge to confluence with the Colorado River, and Little Salt Wash from Fruita discharge to confluence with the Colorado River for D.O., F coli., NH3, Cd, Cu, Ag, Ni, B, Hg, NO2 = exiting quality 
PARTIES TO THE RULEMAKING HEARING
1.	Trapper Mining Inc.
2.	The City of Grand Junction
3.	Corrections Corporation of America
4.	Keystone Resort
5.	U.S. EPA Region VII
6.	The City of Black Hawk and the Black Hawk/Central City Sanitation District
7.	The City of Colorado Springs
8.	Information Network for Responsible Mining
9.	Seneca Coal Company