Colorado department of public health and environment
WATER QUALITY CONTROL COMMISSION
5 ccr 1002-37
REGULATION NO.  37
CLASSIFICATIONS AND NUMERIC STANDARDS
FOR
LOWER COLORADO RIVER BASIN
. . . .
REGION:11

BASIN:  Lower Colorado River	

Desig	

Classifications	
NUMERIC STANDARDS	
TEMPORARY
MODIFICATIONS
AND
QUALIFIERS	

Stream Segment Description			PHYSICAL
and
BIOLOGICAL
	
INORGANIC
mg/l	
METALS
ug/l		
2b.	Mainstem of the Colorado River from a point immediately above the confluence with Rapid Creek to immediately above the confluence of the Gunnison River.		Aq Life Warm 1
Recreation E
Water Supply
Agriculture	T=TVS(WS-II) oC
D.O. = 5.0 mg/l
pH = 6.5-9.0
E.Coli=126/100ml	NH3(ac/ch)=TVS
Cl2(ac)=0.019
Cl2(ch)=0.011
CN=0.005	S=0.002
B=0.75
NO2=0.05
NO3=10
Cl=250
SO4=WS	As(ac)=340
As(ch)=0.02(Trec)
Cd(ac/ch)=TVS
CrIII(ac)=50(Trec)
CrVI(ac/ch)=TVS
Cu(ac/ch)=TVS	Fe(ch)=WS(dis)
Fe(ch)=1000(Trec)
Pb(ac/ch)=TVS
Mn(ch)=WS(dis)
Mn(ac/ch)=TVS
Hg(ch)=0.01(tot)	Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac/ch)=TVS
Zn(ac/ch)=TVS		
4e.	Mainstem of Dry Creek including all tributaries and wetlands from the source to immediately above the Last Chance Ditch.	UP	Aq Life Cold 2
Recreation N
Agriculture	T=TVS(CS-II) oC
D.O.=5.0 mg/l
pH=6.5-9.0
E.Coli=630/100ml	NH3(ac/ch)=TVS
Cl2(ac)=0.019
Cl2(ch)=0.011
CN=0.005	S=0.002
B=0.75
NO2=0.05
NO3=100	As(ac)=340
As(ch)=100(Trec)
Cd(ac/ch)=TVS
CrIII(ac/ch)=TVS
CrVI(ac/ch)=TVS
Cu(ac/ch)=TVS	Fe(ch)=1000(Trec)
Pb(ac/ch)=TVS
Mn(ac/ch)=TVS
Hg(ch)=0.01(tot)	Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac/ch)=TVS
Zn(ac/ch)=TVS	Temporary Modifications:
Cu(ac/ch)=existing quality
Fe(ch)=existing quality(Trec)
(Type iii)
Expiration 12/31/2013.	
13b.	All tributaries to the Colorado River, including wetlands, from the Government Highline Canal Diversion to a point immediately below Salt Creek, and downgradient from the Government Highline Canal, the Orchard Mesa Canal No. 2, Orchard Mesa Drain, Stub Ditch and the northeast Colorado National Monument boundary.	
UP	Aq Life Warm 2
Recreation E
Agriculture	T=TVS(WS-II) oC
D.O.= 5.0 mg/l
pH = 6.5-9.0
E.Coli=126/100ml	NH3(ac/ch)=TVS
Cl2(ac)=0.019
Cl2(ch)=0.011
CN=0.005	S=0.002
B=0.75
NO2=0.05
NO3=100	As(ac)=340
As(ch)=100(Trec)
Cd(ac/ch)=TVS
CrIII(ac/ch)=TVS
CrVI(ac/ch)=TVS
Cu(ac/ch)=TVS	Fe(ch)=1000(Trec)
Pb(ac/ch)=TVS
Mn(ac/ch)=TVS
Hg(ch)=0.01(tot)
	Ni(ac/ch)=TVS
Se(ac/ch)=TVS Ag(ac/ch)=TVS
Zn(ac/ch)=TVS	Temporary modification:
Persigo Wash from the Grand Junction discharge to the confluence with the Colorado River for Dec-Feb:
T(DM)=18.0 oC
T(MWAT)=18.0 oC
(Type iii).  
Expiration date 6/30/2013.	
13d.	Coal Canyon Creek downgradient ot the Government Highline Canal.		Aq Life Warm 2
Recreation P
Agriculture	T=TVS(WS-II) oC
D.O. = 5.0 mg/l
pH = 6.5-9.0
E. Coli=205/100ml	NH3(ac/ch)=TVS
Cl2(ac)=0.019
Cl2(ch)=0.011
CN=0.005	S=0.002
B=5.0
NO2=10
NO3=100	As(ac)=340
As(ch)=100(Trec)
Cd(ac/ch)=TVS
CrIII(ac/ch)=TVS
Cu(ac)=0.96e(0.9801 [ln(hard)]-1.4747)
Cu(ch)=0.96e(0.5897 [ln(hard)]-0.3193)	Fe(ch)=1000
Pb(ac/ch)=TVS
Mn(ac/ch)=TVS
Hg(ch)=0.01(tot)
	Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac/ch)=TVS
Zn(ac/ch)=TVS		

37.29	STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE JUNE 13, 2011 RULEMAKING REGARDING TEMPORARY MODIFICATIONS; EFFECTIVE DATE JANUARY 1, 2012
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’s decision to delay consideration of nutrient criteria until March 2012, resulted in cancelation of the December 2011 review of temporary modifications.  Accordingly, the Commission considered the expiration dates of temporary modifications expiring on or before December 31, 2012 in a written comment rulemaking.  
The Commission extended the expiration date of the following temporary modification to December 31, 2013.  It will be reviewed again in a Temporary Modification hearing in December 2012.
Lower Colorado segment 4e (Cu, Fe)
The Commission extended the expiration date of the following temporary modification to June 30, 2013.  It is anticipated that the City of Grand Junction will propose a site-specific temperature standard for consideration at the December 2012 Temporary Modification hearing.
Lower Colorado segment 13b, Persigo Wash from the Grand Junction discharge to the confluence with the Colorado River (Temperature)
The following temporary modifications were deleted because they will have expired as of the effective date of this revision:
Lower Colorado segment 2b (NH3)
Lower Colorado segment 13b (NH3)
Lower Colorado segment 13d (Se, expired 5/31/2011).