COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT
WATER QUALITY CONTROL COMMISSION
5 CCR 1002-36
REGULATION NO. 36
CLASSIFICATIONS AND NUMERIC STANDARDS
FOR
RIO GRANDE BASIN
. . . .
36.6 	TABLES
. . . .
STREAM CLASSIFICATIONS and WATER QUALITY STANDARDS
REGION: 8
BASIN: Rio Grande	Desig	Classifications	NUMERIC STANDARDS	TEMPORARY
MODIFICATIONS
AND
QUALIFIERS	
			PHYSICAL
and
BIOLOGICAL	INORGANIC
mg/l	METALS
ug/l		
Stream Segment Description							

4a.	Mainstem of the Rio Grande from a point immediately above the confluence with Willow Creek to the Rio Grande/Alamosa County line.		
Aq Life Cold 1
Recreation E
Water Supply
Agriculture	
T=TVS (CS-II) °C
D.O. = 6.0 mg/l
D.O. (sp)=7.0 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	
Standards effective through 12/31/2016

As(ac)=340
As(ch)=0.02(Trec)
Cd(ac)=TVS(tr)
Cd(ch)=TVS
CrIII(ac)=50(Trec)
CrIII(ch)=TVS
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(Trec)
Mo(ch)=160(Trec)
Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac)=TVS
Ag(ch)=TVS(tr)
Zn(ac/ch)=TVS

Tier 1 standards effective 1/1/2017 through 12/31/2018

As(ac)=340
As(ch)=0.02(Trec)
CrIII(ac)=50(Trec)
CrIII(ch)=TVS
CrVI(ac/ch)=TVS
Cu(ac/ch)=TVS
Fe(ch)=WS(dis) 
Fe(ch)=1000(Trec)
Pb(ac)=TVS
Mn(ac)=TVS
Hg(ch)=0.01(Trec)
Mo(ch)=160(Trec)
Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac)=TVS
Ag(ch)=TVS(tr)

low flow*
Cd(ac/ch)=2.6/1.5
Pb(ch)=3.0
Mn(ch)=165
Zn(ac/ch)=548/393

high flow**
Cd(ac/ch)=1.0/0.63
Pb(ch)=1.3
Mn(ch)=WS(dis)
Zn(ac/ch)=272/183	
Tier 2 standards effective from 1/1/2019

As(ac)=340
As(ch)=0.02(Trec)
CrIII(ac)=50(Trec)
CrIII(ch)=TVS
CrVI(ac/ch)=TVS
Cu(ac/ch)=TVS
Fe(ch)=WS(dis) 
Fe(ch)=1000(Trec)
Pb(ac)=TVS
Mn(ac)=TVS
Hg(ch)=0.01(Trec)
Mo(ch)=160(Trec)
Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac)=TVS
Ag(ch)=TVS(tr)

low flow*
Cd(ac/ch)=2.0/0.88
Pb(ch)=1.5
Mn(ch)=92
Zn(ac/ch)=306/148

high flow**
Cd(ac/ch)=0.83/0.51
Pb(ch)=0.75
Mn(ch)=WS(dis)
Zn(ac/ch)=225/136
	
Temporary Modifications:
Type B:
Cd(ch)=current condition
Pb(ch)= current condition
Zn(ch)= current condition
Expiration Date 
12/31/2016

Temporary modification:
As(ch)=hybrid
Expiration date of 12/31/21.

*Low flow is August-March
**High flow is April-July	
. . . .

7.	Mainstem of West Willow Creek from the Park Regent Mine dump to the confluence with East Willow Creek, Mainstem of Willow Creek, including all tributaries from the confluence of East and West Willow Creeks, to the confluence with the Rio Grande.	

UP	
Aq Life Cold 2
Recreation  E
Agriculture
	
T=TVS(CS-II) oC
D.O.= 6.0 mg/l
D.O.(sp)=7.0 mg/l
pH = 6.5-9.0
E.Coli=126/100ml
Chla=150 mg/m2 C	
NH3(ac/ch)=TVS
Cl2(ch)=0.011
CN=0.005	
S=0.002
B=0.75
NO2=10
NO3=100
P=110 ug/l (tot) C	
Standards effective through 12/31/2016

As(ac)=340
As(ch)=100(Trec)
Cd(ac/ch)=TVS
CrIII(ac/ch)=TVS
CrIII(ch)=100(Trec)
CrVI(ac/ch)=TVS
Cu(ac/ch)=TVS
Fe(ch)=1000(Trec)
Pb(ac/ch)=TVS
Mn(ac/ch)=TVS
Hg(ch)=0.01(Trec)
Mo(ch)=160(Trec)
Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ac/ch)=TVS
Zn(ac/ch)=TVS	
Tier 1 standards effective 1/1/2017 through 12/31/2018

As(ac)=340
As(ch)=100(Trec)
CrIII(ac/ch)=TVS
CrIII(ch)=100(Trec)
CrVI(ac/ch)=TVS
Fe(ch)=1000(Trec)
Hg(ch)=0.01(Trec)
Mo(ch)=160(Trec)
Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ch)=TVS

West Willow

Cd(ac/ch)=163/21
Cu(ac/ch)=227/8.9
Pb(ac/ch)=1014/104
Mn(ac/ch)=TVS

Ag(ac)=1.3
Zn(ac/ch)=24000/
5977

Windy Gulch
Cd(ac/ch)=9.1/6.3
Cu(ac/ch)=TVS/5.8
Pb(ac/ch)=TVS
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=2804/1914

Willow mainstem
low flow*
Cd(ac/ch)=17.5/15.4
Cu(ac/ch)=TVS
Pb(ac/ch)= TVS/30
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=4541/3917

high flow**
Cd(ac/ch)=15.6/10.3
Cu(ac/ch)=TVS
Pb(ac/ch)=TVS/22
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=4190/3009	
Tier 2 standards effective from 1/1/2019

As(ac)=340
As(ch)=100(Trec)
CrIII(ac/ch)=TVS
CrIII(ch)=100(Trec)
CrVI(ac/ch)=TVS
Fe(ch)=1000(Trec)
Hg(ch)=0.01(Trec)
Mo(ch)=160(Trec)
Ni(ac/ch)=TVS
Se(ac/ch)=TVS
Ag(ch)=TVS

West Willow
low flow*
Cd(ac/ch)=67/50
Cu(ac/ch)=17.6/15.0
Pb(ac/ch)=268/183
Mn(ac/ch)=TVS/
1779
Ag(ac)=TVS
Zn(ac/ch)=11873/
11022

high flow**
Cd(ac/ch)=32/19.2
Cu(ac/ch)=15.0/9.4
Pb(ac/ch)=103/47
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=8772/5611

Windy Gulch
Cd(ac/ch)=9.1/6.3
Cu(ac/ch)= TVS/5.8
Pb(ac/ch)=TVS
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=2804/1914

Willow mainstem
low flow*
Cd(ac/ch)=13.9/11.2
Cu(ac/ch)=TVS
Pb(ac/ch)=TVS/18.6
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=2521/1733

high flow**
Cd(ac/ch)=14.5/8.9
Cu(ac/ch)=TVS
Pb(ac/ch)=TVS/13.1
Mn(ac/ch)=TVS
Ag(ac)=TVS
Zn(ac/ch)=3635/2373
	
Temporary Modifications Type B:

West Willow
Cd(ac)=163
Cd(ch)=21.2
Cu(ac)=227
Cu(ch)=8.9
Pb(ac)=1014
Pb(ch)=104
Ag(ac)=1.32
Zn(ac)=24000
Zn(ch)=5977

Windy Gulch
Cd(ac)=9.1
Cd(ch)=6.3
Cu(ch)=5.8
Zn(ac)=2804
Zn(ch)=1914

Willow
Cd(ac)=30.8
Cd(ch)=17.9
Cu(ac)=6.4
Cu(ch)=5.6
Pb(ac)=38.0
Pb(ch)=31.3
Zn(ac)=6763
Zn(ch)=4660

Expiration Date 
12/31/2016

*Low flow is August-March
**High flow is April-July	
. . . .
36.35	STATEMENT OF BASIS SPECIFIC STATUTORY AUTHORITY AND PURPOSE DECEMBER 9, 2013 RULEMAKING; FINAL ACTION MARCH 11, 2014 EFFECTIVE DATE JUNE 30, 2014
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 considered a proposal for feasibility-based site-specific standards for Rio Grande segments 4a (mainstem of Rio Grande River) and 7 (Willow Creek) to replace the existing temporary modifications of “Current Condition” for cadmium, lead and zinc in segment 4a, and the ambient based numeric temporary modifications for cadmium, copper, lead, silver and zinc in segment 7.  
The Commission extended the existing Temporary Modifications for Rio Grande segment 4a and Rio Grande segment 7 from 6/30/2015 to 12/31/2016.  The Commission also adopted two tiers of site-specific standards for those segments based on the feasibility of reversing historic man-induced sources of metals.  The Commission adopted Tier 1 standards which are effective from 1/1/2017 through 12/31/2018.  These standards represent predicted improvements in water quality due to the dilution effect of treated effluent from the Bulldog Mine.  The Commission also adopted Tier 2 standards, which are effective after 1/1/2019.  The Tier 2 standards reflect the further water-quality improvement predicted by a 90% reduction in flow and metal load from the Nelson Tunnel, and a predicted 50% reduction in metal load from the Solomon Mine, in addition to dilution from treated effluent from the Bulldog Mine.  The adopted site-specific standards are intended to set water-quality goals for both segments that reflect the lowest ambient concentrations that are feasible to achieve.  The Commission expects revisions will be made to the tiered underlying standards as new information become available.
The Commission adopted the proposed extension of the existing Temporary Modifications with the expectation that Rio Grande Silver will propose a sampling plan for the December 2014 Temporary Modification Hearing.  The Commission expects the plan to address key areas of uncertainty that need to be better quantified during high flow and low flow conditions such as:
1.	Lead and manganese load attenuation below the Nelson Tunnel.
2.	Achievable manganese concentrations in the Bulldog Mine effluent.
3.	Groundwater interactions in the Willow Creek floodplain between Creede and the Rio Grande River.
4.	Groundwater influx in West Willow Creek below the Nelson Tunnel.
5.	Groundwater influx from the Rio Grande Seep near Wagon Wheel Gap.
PARTIES TO THE RULEMAKING HEARING
1.	Rio Grande Silver, Inc.
2.	Black Hawk/Central City Sanitation District and City of Black Hawk
3.	Centennial Water & Sanitation District, City of Littleton, City of Englewood
4.	Colorado Parks and Wildlife
5.	Homestake Mining Company of California
6.	Metro Wastewater Reclamation District
7.	South Platte Coalition for Urban River Evaluation (SP CURE)
8.	City of Boulder
9.	Seneca Coal
10.	Tri-State Generation and Transmission Association
11.	City of Fort Collins
12.	MillerCoors, LLC
13.	Environmental Protection Agency
14.	Barr Lake and Milton Reservoir Watershed Association
15.	Plum Creek Water Reclamation Authority