COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT 
WATER QUALITY CONTROL COMMISSION 
5 CCR 1002-34
REGULATION NO. 34
CLASSIFICATIONS AND NUMERIC STANDARDS
FOR
SAN JUAN AND DOLORES RIVER BASINS
34.1	AUTHORITY
These regulations are promulgated pursuant to section 25-8-101 et seq. C.R.S., as amended, and in particular, 25-8-203 and 25-8-204. 
34.2 	PURPOSE
These regulations establish classifications and numeric standards for the San Juan and the Dolores River Basins, including all tributaries and standing bodies of water south of the northern Dolores County lines, as indicated in section 34.6. The classifications identify the actual beneficial uses of the water.  The numeric standards are assigned to determine the allowable concentrations of various parameters.  Discharge permits will be issued by the Water Quality Control Division to comply with basic, narrative, and numeric standards and control regulations so that all discharges to waters of the state protect the classified uses. (See Regulation No. 31 section 31.14).  It is intended that these and all other stream classifications and numeric standards be used in conjunction with and be an integral part of Regulation No. 31 Basic Standards and Methodologies for Surface Water. 
34.3 	INTRODUCTION
These regulations and tables present the classifications and numeric standards assigned to stream segments listed in the attached tables (See section 34.6(4)).  As additional stream segments are classified and numeric standards for designated parameters are assigned for this drainage system, they will be added to or replace the numeric standards in the tables in section 34.6(4).  Any additions or revisions of classifications or numeric standards can be accomplished only after public hearing by the Commission and proper consideration of evidence and testimony as specified by the statute and the “basic regulations”. 
34.4 	DEFINITIONS
See the Colorado Water Quality Control Act and the codified water quality regulations for definitions. 
34.5 	BASIC STANDARDS
(1)	TEMPERATURE
All waters of the San Juan/Dolores River Basin are subject to the following standard for temperature.  (Discharges regulated by permits, which are within the permit limitations, shall not be subject to enforcement proceedings under this standard).  Temperature shall maintain a normal pattern of diurnal and seasonal fluctuations with no abrupt changes and shall have no increase in temperature of a magnitude, rate, and duration deemed deleterious to the resident aquatic life.  This standard shall not be interpreted or applied in a manner inconsistent with section 25-8-104, C.R.S.  
(2) 	QUALIFIERS
See Basic Standards and Methodologies for Surface Water for a listing of organic standards at 31.11 and metal standards found at 31.16 Table III.  The column in the tables headed “Water + Fish” are presumptively applied to all aquatic life class 1 streams which also have a water supply classification, and are applied to aquatic life class 2 streams which also have a water supply classification, on a case-by-case basis as shown in the Tables 34.6(4).  The column in the tables at 31.11 and 31.16 Table III headed “Fish Ingestion” is presumptively applied to all aquatic life class 1 streams which do not have a water supply classification, and are applied to aquatic life class 2 streams which do not have a water supply classification, on a case-by-case basis as shown in Tables 34.6(4). 
(3) 	URANIUM
(a) 	All waters of the San Juan/Dolores River Basin, are subject to the following basic standard for uranium, unless otherwise specified by a water quality standard applicable to a particular segment.  However, discharges of uranium regulated by permits which are within these permit limitations shall not be a basis for enforcement proceedings under this basic standard. 
(b) 	Uranium level in surface waters shall be maintained at the lowest practicable level. 
(c) 	In no case shall uranium levels in waters assigned a water supply classification be increased by any cause attributable to municipal, industrial, or agricultural discharges so as to exceed 16.8-30 µg/l or naturally-occurring concentrations (as determined by the State of Colorado), whichever is greater. 
(i)	The first number in the 16.8-30 ug/l range is a strictly health-based value, based on the Commission’s established methodology for human health-based standards. The second number in the range is a maximum contaminant level, established under the federal Safe Drinking Water Act that has been determined to be an acceptable level of this chemical in public water supplies, taking treatability and laboratory detection limits into account. Control requirements, such as discharge permit effluent limitations, shall be established using the first number in the range as the ambient water quality target, provided that no effluent limitation shall require an “end-of-pipe” discharge level more restrictive than the second number in the range. Water bodies will be considered in attainment of this standard, and not included on the Section 303(d) List, so long as the existing ambient quality does not exceed the second number in the range.
 (4) 	INDIAN RESERVATIONS
Some of the waterbodies in the San Juan/Dolores River Basin cross boundaries of Indian Reservations of the Southern Ute and Ute Mountain Ute Tribes.  The Commission has included water quality classifications and standards on lands within the boundaries of these reservations in order to avoid a gap in the classifications and standards adopted for the river basins in question.  The Southern Ute Indian tribe has not yet been granted authority by EPA to conduct their own water quality program, and EPA has granted the Ute Mountain Ute Indian tribe’s application for treatment as a state with respect to adoption of water quality standards.  The Commission intends that the classifications and standards that it is adopting apply to the lands in question only to the extent that the state has jurisdiction and is not attempting to resolve that jurisdictional issue here.  Segments within Reservation boundaries are noted in the segment description and last column of Tables 34.6(4). 
34.6 	TABLES
(1) 	Introduction
The numeric standards for various parameters in the attached tables were assigned by the Commission after a careful analysis of the data presented on actual stream conditions and on actual and potential water uses. 
Numeric standards are not assigned for all parameters listed in the tables attached to Regulation No. 31.  If additional numeric standards are found to be needed during future periodic reviews, they can be assigned by following the proper hearing procedures. 
(2) 	Abbreviations:
(a)	The following abbreviations are used in the attached tables:  
ac 	= 	acute (1-day) 
Ag 	= 	silver 
Al 	= 	aluminum 
As 	= 	arsenic 
B 	= 	boron 
Ba 	= 	barium 
Be 	= 	beryllium 
Cd 	= 	cadmium 
oC	=	degrees Celsius
ch 	= 	chronic (30-day) 
Cl 	= 	chloride 
CL	=	cold lake temperature tier
CLL	=	cold large lake temperature tier
Cl2	= 	residual chlorine 
CN 	= 	free cyanide 
CrIII 	= 	trivalent chromium 
CrVI 	= 	hexavalent chromium 
CS-I	=	cold stream temperature tier one
CS-II	=	cold stream temperature tier two
Cu 	= 	copper 
dis 	= 	dissolved 
D.O. 	= 	dissolved oxygen 
DM	=	daily maximum temperature 
E.coli 	= 	escherichia coli 
F 	= 	fluoride 
Fe 	= 	iron 
Hg 	= 	mercury 
mg/l 	= 	milligrams per liter 
ml 	= 	milliliters 
Mn 	= 	manganese 
Mo	=	molybdenum
MWAT	=	maximum weekly average temperature 
NH3	= 	ammonia as N(nitrogen) 
Ni 	= 	nickel 
NO2	= 	nitrite as N (nitrogen) 
NO3	= 	nitrate as N (nitrogen) 
OW 	= 	outstanding waters 
P 	= 	phosphorus 
Pb 	= 	lead 
S 	= 	sulfide as undissociated H2S (hydrogen sulfide) 
Sb 	= 	antimony 
Se 	= 	selenium 
SO4	= 	sulfate 
sp 	= 	spawning 
T	=	temperature
Tl 	= 	thallium 
tr 	= 	trout 
Trec 	= 	total recoverable 
TVS 	= 	table value standard 
U 	= 	uranium 
µg/l 	= 	micrograms per liter 
UP 	= 	use-protected 
WAT	=	weekly average temperature
WS	=	water supply
WS-II	=	warm stream temperature tier two
WS-III	=	warm stream temperature tier three
WL	=	warm lake temperature tier
Zn 	= 	zinc 
(b)         In addition, the following abbreviations are used:  
	Fe(ch) 	= 	WS(dis) 
Mn(ch) 	= 	WS(dis) 
SO4	= 	WS 
These abbreviations mean:  For all surface waters with an actual water supply use, the less restrictive of the following two options shall apply as numerical standards, as specified in the Basic Standards and Methodologies at 31.16 Table II and III:  
(i) 	existing quality as of January 1, 2000; or 
(ii) 	Iron 	= 		300 µg/l (dissolved) 
Manganese 	= 	50µg/l (dissolved) 
SO4	= 		250 mg/l 
For all surface waters with a “water supply” classification that are not in actual use as a water supply, no water supply standards are applied for iron, manganese or sulfate, unless the Commission determines as the result of a site-specific rulemaking hearing that such standards are appropriate. 
(c)	As used in the Temporary Modifications and Qualifiers column of the tables in 34.6(4), the term “type A” refers to a Temporary Modification adopted pursuant to subsection 31.7(3)(a)(ii)(A) of the Basin Standards and Methodologies for Surface Water (i.e., “there is significant uncertainty regarding the water quality standard necessary to protect current and/or future use”).  As used in the Temporary Modifications and Qualifiers column of the tables in 34.6(4), the term “type B” refers to a Temporary Modification adopted pursuant to subsection 31.7(3)(a)(ii)(B) of the Basin Standards and Methodologies for Surface Water (i.e., “there is significant uncertainty regarding the extent to which existing quality is the result of natural or irreversible human-induced conditions”).  As used in the Temporary Modifications and Qualifiers column of the tables in 34.6(4), the term “type C” refers to a Temporary Modification adopted pursuant to subsection 31.7(3)(a)(ii)(C) of the Basin Standards and Methodologies for Surface Water (i.e., “there is significant uncertainty regarding the timing of implementing attainable source controls or treatment”).
(3) 	Table Value Standards
In certain instances in the attached tables, the designation “TVS” is used to indicate that for a particular parameter a “table value standard” has been adopted.  This designation refers to numerical criteria set forth in the Basic Standards and Methodologies for Surface Water.  The criteria for which the TVS are applicable are on the following table.  
TABLE VALUE STANDARDS 
(Concentrations in ug/l unless noted) 	
____________ 	_______________________________________________________ 	
PARAMETER(1)	TABLE VALUE STANDARDS(2)(3)	
____________ 	_______________________________________________________ 	
Aluminum (Trec)	Acute = e(1.3695[ln(hardness)]+1.8308)
pH equal to or greater than 7.0
	     Chronic=e(1.3695[ln(hardness)]-0.1158)
pH less than 7.0
	Chronic= e(1.3695[ln(hardness)]-0.1158) or 87, whichever is less
	
Ammonia (4)	Cold Water = (mg/l as N)Total

 	Warm Water = (mg/l as N)Total

____________ 	_______________________________________________________ 	
NH3 = old TVS  	Cold Water Acute = 0.43/FT/FPH/2(4 old)in mg/l (N) 	
 	Warm Water Acute = 0.62/FT/FPH/2(4 old)in mg/ (N) 	
____________ 	_______________________________________________________ 	
Cadmium 	Acute = (1.136672-[ln(hardness)x(0.041838)])xe0.9151[ln(hardness)]-3.1485	
 	Acute(Trout) = (1.136672-[ln(hardness)x(0.041838)])xe0.9151[ln(hardness)]-3.6236	
 	Chronic = (1.101672-[ln(hardness)x(0.041838)]e0.7998[ln(hardness)]-4.4451	
____________ 	_______________________________________________________ 	
Chromium III(5)	Acute = e(0.819[ln(hardness)]+2.5736)	
 	Chronic= e(0.819[ln(hardness)]+0.5340)	
____________ 	_______________________________________________________ 	
Chromium VI(5)	Acute = 16 	
 	Chronic = 11 	
____________ 	_______________________________________________________ 	
Copper 	Acute = e(0.9422[ln(hardness)]-1.7408)	
 	Chronic = e(0.8545[ln(hardness)]-1.7428)	
____________ 	_______________________________________________________ 	
Lead 	Acute = (1.46203-[ln(hardness)*(0.145712)])*e(1.273[ln(hardness)]-1.46)	
 	Chronic = (1.46203-[ln(hardness)*(0.145712)])*e(1.273[ln(hardness)]-4.705)	
____________ 	_______________________________________________________ 	
Manganese 	Acute = e(0.3331[ln(hardness)]+6.4676)	
 	Chronic = e(0.3331 [ln(hardness)]+5.8743)	
____________ 	_______________________________________________________ 	
Nickel 	Acute = e(0.846[ln(hardness)]+2.253)	
 	Chronic = e(0.846[ln(hardness)]+0.0554)	
____________ 	_______________________________________________________ 	
Selenium(6)	Acute = 18.4 	
 	Chronic = 4.6 	
____________ 	_______________________________________________________ 	
Silver 	Acute = ½e(1.72[ln(hardness)]-6.52)	
 	Chronic = e(1.72[ln(hardness)]-9.06)	
 	Chronic(Trout) = e(1.72[ln(hardness)]-10.51)	
____________ 	_______________________________________________________ 	
Temperature	TEMPERATURE TIER	TIER CODE	SPECIES EXPECTED TO BE PRESENT	APPLICABLE MONTHS	TEMPERATURE STANDARD (OC)	
					MWAT	DM	
	Cold Stream Tier 1	CS-I	brook trout, cutthroat trout	June – Sept.	17.0	21.7	
				Oct. – May	9.0	13.0	
	Cold Stream Tier 2	CS-II	all other cold-water species	April – Oct.	18.3	23.9	
				Nov. – March	9.0	13.0	
	Cold Lakes	CL	brook trout, brown trout, cutthroat trout, lake trout, rainbow trout, Arctic grayling, sockeye salmon	April – Dec.	17.0	21.2	
				Jan. – March	9.0	13.0	
	Cold Large Lakes (>100 acres surface area)	CLL	rainbow trout, brown trout, lake trout	April – Dec.	18.3	23.8	
				Jan. – March	9.0	13.0	
	Warm Stream Tier 2	WS-II	brook stickleback, central stoneroller, creek chub, longnose dace, Northern redbelly dace, finescale dace, razorback sucker, white sucker	March – Nov.	27.5	28.6	
				Dec. – Feb.	14.3	15.9	
	Warm Stream Tier 3	WS-III	all other warm-water species	March – Nov.	28.7	31.8	
				Dec. – Feb. 	14.3	15.9	
	Warm Lakes	WL	black crappie, bluegill, common carp, gizzard shad, golden shiner,  largemouth bass, Northern pike,  pumpkinseed, sauger, smallmouth bass, spottail shiner, striped bass, tiger muskellunge, walleye, wiper, white bass, white crappie, yellow perch	April – Dec.	26.3	29.5	
				Jan. – March	13.2	14.8	
Uranium 	Acute = e(1.1021[ln(hardness)]+2.7088)	
 	Chronic = e(1.1021[ln(hardness)]+2.2382)	
____________ 	_______________________________________________________ 	
Zinc 	Acute = 0.978 e(0.8525[ln(hardness)]+1.0617)	
 	Chronic =  0.986 e(0.8525[ln(hardness)]+0.9109) 
if hardness less than 113 mg/l CaCO3 
Chronic (sculpin) = e(2.227[ln(hardness)]-5.604)	
TABLE VALUE STANDARDS - FOOTNOTES
(1) 	Metals are stated as dissolved unless otherwise specified. 
(2) 	Hardness values to be used in equations are in mg/l as calcium carbonate and shall be no greater than 400 mg/L, except for aluminum for which hardness shall be no greater than 220 mg/L.  The hardness values used in calculating the appropriate metal standard should be based on the lower 95 per cent confidence limit of the mean hardness value at the periodic low flow criteria as determined from a regression analysis of site-specific data.  Where insufficient site-specific data exists to define the mean hardness value at the periodic low flow criteria, representative regional data shall be used to perform the regression analysis.  Where a regression analysis is not appropriate, a site-specific method should be used. In calculating a hardness value, regression analyses should not be extrapolated past the point that data exist. 
(3) 	Both acute and chronic numbers adopted as stream standards are levels not to be exceeded more than once every three years on the average. 
(4 old) 	FT = 100.03(20-TCAP); 
Where TCAP is ≤ T ≤ 30 
FT = 100.03(20-T); 
Where 0 is ≤ T ≤ TCAP 
TCAP = 20o C cold water aquatic life species present 
TCAP = 25o C cold water aquatic life species absent 
FPH = 1; Where 8 <pH ≤9 
FPH = 1 + 10(7.4-pH); 
              1.25		Where 6.5 ≤ pH ≤ 8 
FPH means the acute pH adjustment factor, defined by the above formulas. 
FT means the acute temperature adjustment factor, defined by the above formulas. 
T means temperature measured in degrees celsius. 
TCAP means temperature CAP; the maximum temperature which affects the toxicity of ammonia to salmonid and non-salmonid fish groups. 
NOTE: If the calculated acute value is less than the calculated chronic value, then the calculated chronic value shall be used as the acute standard. 
(4)  	For acute conditions the default assumption is that salmonids could be present in cold water segments and should be protected, and that salmonids do not need to be protected in warm water segments.  For chronic conditions, the default assumptions are that early life stages could be present all year in cold water segments and should be protected.  In warm water segments the default assumption is that early life stages are present and should be protected only from April 1 through August 31.  These assumptions can be modified by the Commission on a site-specific basis where appropriate evidence is submitted. 
(5) 	Unless the stability of the chromium valence state in receiving waters can be clearly demonstrated, the standard for chromium should be in terms of chromium VI.  In no case can the sum of the instream levels of Hexavalent and Trivalent Chromium exceed the water supply standard of 50 ug/l total chromium in those waters classified for domestic water use. 
(6) 	Selenium is a bioaccumulative metal and subject to a range of toxicity values depending upon numerous site-specific variables.  

[INSERT TABLES]

. . . .
34.37	STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; SEPTEMBER 10, 2012 RULEMAKING; FINAL ACTION NOVEMBER 5, 2012; EFFECTIVE DATE MARCH 30, 2013
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:
A.	Waterbody Segmentation
The Commission split lakes and reservoirs from segments that also contained streams, so that new temperature standards could be adopted.  Lakes and reservoirs were deleted from the following segments that previously encompassed streams and lakes and reservoirs:
San Juan River segments: 1a, 3, 4, 5, 6a, 9a, 9b, 11a, 11b, 12a
Piedra River segments: 1, 5, 6a, 6b 
Los Pinos River segments: 1, 4a, 6a, 6b
Animas and Florida River segments: 1, 3c, 6, 7, 8, 12a, 13b, 13c
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 1, 3a, 3b, 4a, 6a, 6b, 7a, 8a, 8b, 10a, 10b
Upper Dolores River segments: 1, 5a, 11
The following segments were created for lakes and reservoirs:
San Juan River segments: 13, 14, 15a, 15b, 16, 17, 18a, 18b, 19
Piedra River segments: 8, 9, 10, 11a, 11b 
Los Pinos River segments: 8, 9, 10, 11a, 11b
Animas and Florida River segments: 16, 17, 18, 19, 20, 21, 22, 23, 24
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22
Upper Dolores River segments: 12, 13, 14, 15
The following segment was deleted when the constituent water bodies were merged with other segments:
San Juan River segment: 12b
Some existing stream segments were divided into two or more segments at the point where a change in temperature tiers occurred.  The following segments were created or revised to facilitate adoption of the new temperature standards into individual segments:
San Juan River segments: 1a, 1b, 7, 8, 9a 
Piedra River segments: 2a, 2b 
Animas and Florida River segments: 10a, 10b, 14a, 14b
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 3a, 3c, 4a, 4c, 6a
The following segments were created or revised based upon water quality and/or aquatic life data which showed that streams should be resegmented or grouped with another segment for which there was similar water quality and designated uses:
San Juan River segments: 11b
Animas and Florida River segments: 12a, 12d, 13b, 13d, 14a
Dolores River segments 5a, 5b
The following segment descriptions were edited to improve clarity, fix typographical errors, update numbering and correct spelling:
San Juan River segments: 2, 5, 6a, 9a, 10, 11a, 11b, 12a
Piedra River segments: 4a, 5, 6a
Los Pinos River segments: 7a, 7b, 8
Animas and Florida River segments: 6, 12a, 13a, 13b, 15
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 4b, 7b, 10a, 10b 
Upper Dolores River segment: 1
B.	Revised Aquatic-Life Use Classifications and Standards 
The Commission reviewed information regarding the existing aquatic communities. Class 2 segments with exceptionally high MMI scores, or fish data showing the presence of a wide variety of species, were upgraded from Class 2 to Class 1.
The following segments were upgraded from Warm 2 to Warm 1:
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2b, 5a, 5b 
San Juan River segment: 11b (revised to include water bodies from the former segment 12b)
The following segments were upgraded from Cold 2 to Cold 1:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 2a 
Animas and Florida River segments: 12a, 12d
Fish Ingestion qualifiers were added to the following segments, based upon review of available data:
Piedra River segment 11a
La Plata River, Mancos, River, McElmo Creek and San Juan River segments:  14
Fish Ingestion qualifiers were deleted for the following segment that was upgraded from Class 2 to Class 1, since fish ingestion is presumed for all Class 1 waters:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 2a
The following segment was upgraded from Warm 2 to Cold 1 based on biological data showing that the segments have cold-water species, or cold-water species are expected to be present:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 3c
The following segments were designated as Aquatic Life Warm 2 or Cold 2, but lacked standards to fully support the Aquatic Life Use.  Available data indicates that the Aquatic Life Use is attainable, and therefore the full suite of standards protective of aquatic life was added to the following segments:
San Juan River segments: 3, 12, 19 
Los Pinos River segments: 6a, 6b, 11a, 11b
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 10a, 10b
Some new lake segments were split from stream segments with no Aquatic Life Use.  These new lake segments were designated as Aquatic Life Cold 2, because the Aquatic Life UAAs did not include data from these lakes.  The full suite of standards protective of aquatic life was added to the following segments:
Animas and Florida River segments: 19, 20
A Use Attainability Analysis was prepared to downgrade the following segment from Cold 1 to Warm 1:
San Juan River segment: 8
A Use Attainability Analysis was prepared to remove the Aquatic Life Use and standards: 
Animas and Florida River segment: 13d
C.	Recreation Classifications and Standards
Newly created segments were given the same Recreation Use classification as the segment from which they were split, unless there was insufficient evidence to support keeping that classification, or evidence to show that the use classification was inappropriate or that recreation use had changed.  
The following segments with year-round or seasonal Recreation N standards were upgraded to Recreation E:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 3c
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 14
The following segments with year-round or seasonal Recreation P standards were upgraded to Recreation E:
Piedra River segment: 11a
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 1, 12 
The following segment with year-round or seasonal Recreation N standards was upgraded to Recreation P:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 13 
D.	Water Supply Use Classification and Standards
Based on review of information regarding the location of alluvial wells, where the evidence demonstrates a reasonable potential for a hydrological connection between the surface water and the wells, the Water Supply Use classification and standards were added to the following segments:
San Juan River segments: 10, 11a
Animas and Florida River segments: 9, 13a
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2a, 2b, 3b, 4c, 5a, 8a
Upper Dolores River segment: 3
A Use Attainability Analysis was prepared to remove the Water Supply Use and standards from the following segment: 
Animas and Florida River segment: 13d
E.	Agriculture Standards
A review of the standards associated with the Agriculture Use classification showed that many segments were missing a chronic chromium III standard to protect the use.  The chronic chromium III standard to protect the Aquatic Life Use classification may be not be protective of the Agriculture Use in some high hardness situations.  A chromium III standard of CrIII(ch)=100(Trec), was added to the following segments classified for Agriculture Use, but not for Water Supply, which has a more restrictive chromium III standard:
San Juan River segments: 11b, 18b
Los Pinos River segments: 7a, 7b
Animas and Florida River segment: 3a 
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 6a, 6b, 6c, 7a, 7b, 8b, 8c, 9, 13, 14, 16, 17, 18, 19
Several segments with the Agriculture Use classification were missing a standard for nitrate.  A nitrate standard of 100 mg/l was added to the following segments:
Los Pinos River segments: 7a, 7b
Animas and Florida River segments: 3a, 3c, 4a, 17, 19, 20
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 3a, 5b, 6a, 6b, 6c, 7a, 7b, 8b, 8c, 9, 13, 14, 16, 17, 18, 19, 20
Molybdenum:  In 2010, the Commission adopted a new standard for molybdenum to protect cattle from the effects of molybdenosis.  The table value adopted at that time was 300 ug/l, but included an assumption of 48 mg/day of copper supplementation to ameliorate the effects of molybdenosis.  State and local experts on cattle nutrition indicated that copper supplementation in region is common, but is not universal.  Therefore, copper supplementation assumption was removed from the equation, which yields a standard of 160 ug/l.   The Commission expects that this value may be revised when data on the copper and molybdenum content of local forage becomes available.  The Commission also notes that in view of EPA disapproval of the 300 ug/l table value in the Basic Standards and Methodologies for Surface Water, the Commission intends to review this value during the next Basic Standards triennial review.
The Agriculture Use table value assumes that the safe copper:molybdenum ratio is 4:1. Food and water intake is based on a 273 kg (600 lb) feeder steer consuming 6.8 kg/day of dry matter and 20% of its body weight in water per day. Total copper and molybdenum intakes are calculated from the following equations: 
Cu intake mg/day = [([Cu] forage, mg/kg) x (forage intake, kg/day)] + [([Cu] water, mg/l) x (water intake, L/day)] + (Cu supplementation, mg/day) 
Mo intake mg/day = [([Mo] forage, mg/kg) x (forage intake, kg/day)] + [([Mo] water, mg/l) x (water intake, L/day)] + (Mo supplementation, mg/day) 
The assumed values for these equations are as follows:
[Cu] forage = 7 mg/kg, [Mo] forage = 0.5 mg/kg, forage intake = 6.8 kg/day, [Cu] water = 0.008 mg/L, [Mo] water = 0.375 mg/L, water intake = 54.6 L/day, Cu supplementation = 0 mg/day, Mo supplementation = 0 mg/day. 
A molybdenum standard of 160 ug/l was adopted for all segments in Regulation 34 with an Agriculture Use classification; except for La Plata segment 6c, because grazing is not allowed within Mesa Verde National Park.   No molybdenum standard was applied to Animas and Florida River segment 3b, because it does not have an Agriculture Use classification. 
F.	Changes to Antidegradation Designation
Outstanding Waters:  Based on evidence that shows the water quality meets the requirements of section 31.8(2)(a), and on the presence of conservation populations of native cutthroat trout in all three streams, the Outstanding Waters designation was added to Rio Lado, Little Taylor Creek and Spring Creek (Dolores River segment 5b). The Commission has determined that the evidence demonstrates that the three criteria for an Outstanding Waters designation set forth in section 31.8(2)(a) are met for this proposal.  The Commission also notes that the outreach undertaken by Trout Unlimited as proponent of this designation helps to demonstrate broad support for the conclusion that these waters constitute an outstanding natural resource and that the additional protection provided by this designation is appropriate.
The Commission understands that there are existing land uses, including grazing permits, in place in the watershed.  The evidence demonstrates that these existing land uses are compatible with the Outstanding Waters designation, since the current high level of water quality has been attained with these uses in place.  It is the Commission's intent that this Outstanding Waters designation should not be the basis upon which federal, state or local agencies place more onerous or costly conditions upon permits or approvals existing at the time of the designation, or upon any renewals thereof.
Further, acknowledging that the adoption of the Outstanding Waters designation for identified segments is a discretionary undertaking by the Commission, with such designations not being subject to federal approval or disapproval, the Commission may, in the future, remove the Outstanding Waters designation from any such segment in accordance with the state substantive and procedural rules then in effect.
The Commission has not adopted the Outstanding Waters designations proposed by WildEarth Guardians for multiple segments.  The Commission is not persuaded that the fact of being located within an area identified as a “roadless area” is sufficient to demonstrate that the waters in question constitute an outstanding natural resource.  Moreover, the proponents did not provide adequate data to persuasively demonstrate the current quality of the waters in question.  Finally, the Commission notes that the proponents did not demonstrate a substantial level of public outreach that might have helped to demonstrate a consensus that the criteria in section 31.8(2)(a) are met.
Decoupling Cold 2 and UP:  As part of the Basic Standards hearing of 2005, the Commission eliminated the direct linkage between Cold-Water Aquatic Life Class 2 and the Use-Protected designation.  The Commission reviewed available water quality data for all Cold 2 segments that were Use-Protected to determine if that designation was still warranted.  The following segment(s) are now Reviewable:
Animas and Florida River segments: 17, 19, 20
Decoupling Aquatic Life Warm 2 and UP:   As part of the Basic Standards hearing of 2005, the Commission decided that the presence of a Warm Water Class 2 classification would still be a presumptive basis for applying a Use-Protected designation; however, that presumption can be overcome if there is data showing that the water is of high quality.  The Commission reviewed available water quality data for all Warm 2 segments to determine if the Use-Protected designation is still warranted.  The following segment(s) are now Reviewable:
San Juan River segments: 11b (revised to include water bodies from the former segment 12b), 12
Other Changes to Antidegradation: The following segment was upgraded from “Warm 2” to “Warm 1” and the Antidegradation designation is now Reviewable:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 2b
The following segment was upgraded from “Warm 2” to “Cold 1” and the antidegradation designation is now Reviewable:
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 3c
G.	Ambient Quality-Based Standards
Ambient standards are adopted where natural or irreversible man-induced conditions result in exceedances of table value standards.  The Commission reviewed the information that is the basis for these standards, as well as any new information that would indicate whether they are still appropriate, need to be modified, or should be dropped.  The following segments have ambient-based or other site-specific standards:
Animas and Florida River segments: 2, 3a, 3b, 4a, 7, 8, 9
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 7a, 9
No changes were made to the ambient quality-based standards for these segments.
A site-specific manganese standard of 255 ug/L was added to Dolores Segment 3.  This value was calculated as the 85th percentile of available data from 1/1/1995 – 12/31/2012, and is expected to be representative of conditions on January 1, 2000, consistent with 31.11(6)).
H.	Aquatic Life Metals Standards
New Table Value Standards:  The zinc, zinc sculpin, and aluminum table values were revised in the 2010 Basic Standards hearing.  The acute and chronic zinc, zinc sculpin, and aluminum equations in 34.6(3) were modified to conform to Regulation No. 31.
Site-Specific Zinc Standards for Mottled Sculpin:  In low hardness situations (hardness below 102 mg/L), the zinc equation is not protective of mottled sculpin (Cottus bairdi), a native west-slope fish species.  The Commission did not add a sculpin-specific zinc equation to any segment in Regulation 34.  
The Commission deleted the zinc scuplin standards from the following new and revised lake segments, where mottled sculpin are not expected to be present:
San Juan River segments: 8, 17
Piedra River segments: 8, 10 
Los Pinos River segment: 10 
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 12, 13 
Upper Dolores River segments: 12, 13, 14, 15
Chromium III Standards:  A review of chromium III standards showed that the standard associated with the Water Supply Use classification is not protective of aquatic life where the average hardness is low (less than 61 mg/l).  A chromium III standard, CrIII(ch)=TVS was added to following segments with  Aquatic Life and Water Supply Use classifications that did not previously include this standard:
San Juan River segments: 1a, 1b, 2, 3, 4, 5, 6a, 6b, 7, 8, 9a, 9b, 10, 11a, 11b, 12, 13, 14, 15a, 15b, 16, 17, 18a, 18b, 19
Piedra River segments: 1, 2a, 2b, 3, 4a, 4b, 5, 6a, 6b, 7, 8 , 9, 10, 11a, 11b
Los Pinos River segments: 1, 2a, 2b, 3, 4a, 4b, 5, 8, 9, 10
Animas and Florida River segments: 1, 5a, 5b, 6, 10a, 10b, 11a, 11b, 12a, 12c, 12d, 13b, 13c, 14a, 15, 16, 21, 22, 23, 24
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 1, 3b, 4a, 4b, 11, 12, 15 
Upper Dolores River segments: 1, 2, 3, 4a, 4b, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
The acute chromium III standard, CrIII(ac)=TVS was deleted from the following segments with  Aquatic Life and Water Supply Use classifications that have the CrIII(ac)=50 ug/l standard:
San Juan River segment: 11a
Animas and Florida River segment: 4b
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2a, 2b, 3b
Arsenic Standards: A review of arsenic standards showed that the acute standard for the protection of aquatic life was missing in some segments.  An Acute Arsenic standard of 340 ug/l was added to the following segments:
Los Pinos River segments: 6a, 6b, 7a, 7b, 11a, 11b
I.	Uranium Standards
At the 2010 Basic Standards rulemaking hearing, the Commission changed the Water Supply table value for uranium from 30 ug/L to a hyphenated standard of 16.8-30 ug/L.  The Commission revised the language in 34.5(3)(c) to reflect the change to the basin-wide standard.  A new section 34.5(3)(c)(i) was added to explain the hyphenated standard.  Subsection 34.5(3)(d) was deleted because it was redundant with 34.5(3)(c).
J.	Temporary Modifications
All existing Temporary Modifications were re-examined to determine if they should be allowed to expire or to extend them.   Temporary Modifications were not automatically extended if non-attainment persisted due to revisions made to the Temporary Modification provisions in 2005 and 2010.  
The following segments had Temporary Modifications that were not extended:
San Juan River segment: 11a
Animas and Florida River segments: 2, 3a, 3b, 3c, 4a, 4b, 7, 8, 9
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 8a
The following segments have new or extended “Type A” Temporary Modifications for ammonia:
Animas and Florida River segment: 13b 
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 7a, 8c
Temporary Modifications were added or extended for existing discharges to these segments, based upon evidence that the dischargers could not meet water quality based effluent limits for ammonia.  The Commission’s intent is to preserve the status quo during the term of the Temporary Modification.  Existing discharges to these segments shall continue to be authorized to discharge ammonia at their current permitted concentration and flow levels, including a “report only” value.    The Division will work with the existing dischargers to determine whether the table value standard for ammonia is necessary to protect the Aquatic Life Uses of these segments.  The uncertainty in the standard for each segment may be resolved through a site-specific standard or a discharger specific variance.  The Commission does not intend that Temporary Modifications set at "current condition" will apply to new or expanded facilities. The progress on resolving the uncertainty with the ammonia standards will be reviewed in the annual Temporary Modification hearing in December 2013.
The following segment has a new “Type B” Temporary Modification:
Animas and Florida River segment: 3b 
For Animas River Segment 3b, the Commission adopted a Type B Temporary Modification for copper, cadmium and zinc with a narrative value of “current condition”, and an expiration date of December 31, 2017. The Commission’s intent is to preserve the status quo during the term of the Temporary Modification.  Existing discharges to Animas River Segment 3b shall continue to be authorized to discharge copper, cadmium and zinc at their current permitted concentration and flow levels, including a “report only” value.  Historic mining impacts upstream from Silverton indicate that elevated levels of copper, cadmium and zinc in the Animas River may be due to irreversible human-induced conditions.  Since remediation options are still be evaluated, and some improvement in water quality may be gained, it is not yet feasible to quantify the extent of irreversible impacts.  The Commission does not intend that Temporary Modifications set at "current condition" will apply to new or expanded facilities. The progress on resolving the uncertainty with the cadmium, copper and zinc standards will be reviewed in the annual Temporary Modification hearing in December 2015.
K.	Temperature
New table values were adopted for temperature in the 2007 Basic Standards hearing, and revised in the 2010 Basic Standards hearing.  Temperature standards were applied to individual segments based upon the fish species expected to be present as provided by Parks and Wildlife, temperature data, and other available evidence. 
The following segments have a Cold Stream Tier I temperature standard (CS-I):
San Juan River segments: 1a, 4, 5, 7
Piedra River segments: 1, 2a, 3, 5    
Los Pinos River segments: 1, 4a, 5
Animas and Florida River segments: 1, 3a, 3c, 4a, 4b, 6, 9, 10a, 12a, 12c, 12d, 13b, 14a, 15
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 1, 4a 
Upper Dolores River segments: 1, 2, 3, 5a, 5b, 6, 7, 8, 9, 10, 11
The following segments have a Cold Stream Tier II temperature standard (CS-II):
San Juan River segments: 1b, 2, 6a, 6b, 9a, 9b, 10
Piedra River segments: 2b, 4a, 4b   
Los Pinos River segments: 2a, 2b, 4b, 6a, 6b, 7a, 7b 
Animas and Florida River segments: 5a, 5b, 10b, 11a, 11b, 13a, 13c, 14b
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2a, 3c, 4c
Upper Dolores River segment: 4a
The following segments have a Warm Stream Tier II temperature standard (WS-II):
San Juan River segments: 3, 11a, 11b
Piedra River segment: 6a   
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2b, 3a, 3b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9
The following segments have a Warm Stream Tier III temperature standard (WS-III):
San Juan River segment: 12a
Piedra River segment: 6b
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 6c, 8c, 10a, 10b 
The following segments have a Cold Lakes temperature standard (CL):
San Juan River segments: 13, 15a, 15b, 16, 17
Piedra River segments: 9, 10
Los Pinos River segments: 8, 10, 11a, 11b
Animas and Florida River segments: 16, 17, 18, 19, 20, 21, 23, 24
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 12, 15
Upper Dolores River segments: 12, 14, 15
The following segments have a Large Cold Lakes (greater than 100 acres surface area) temperature standard (CLL):
Piedra River segment: 8   
Los Pinos River segments: 3, 9
Animas and Florida River segments: 12b, 22
La Plata River, Mancos, River, McElmo Creek and San Juan River segment: 4b
Upper Dolores River segments: 4b, 13
The following segments have a Warm Lakes temperature standard (WL):
San Juan River segments: 8, 14, 18a, 18b, 19
Piedra River segments: 7, 11a, 11b
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 11,13, 14, 16, 17, 18, 19, 20, 21, 22
A temperature standard was not adopted for several segments which do not have a designated Aquatic Life Use:
Animas and Florida River segments: 2, 3b, 7, 8, 13d
The Commission recognizes that in some cases there is uncertainty about the temperature standards adopted in this hearing. The uncertainty stems from a lack of data about temperature or the aquatic community or where there is a conflict between the lines of evidence.  In particular, there was very limited data available for segments within the Southern Ute and Ute Mountain Indian Reservations.  It is the Commission's intent that the Division and interested parties work to resolve the uncertainty for the following segments: 
San Juan River segments: 2, 6b, 9b, 11b, 15b, 18b
Piedra River segments: 4b, 6b, 11b   
Los Pinos River segments: 2b, 4b, 6b, 7b, 11b
Animas and Florida River segments: 5b, 11b, 13c, 24
La Plata River, Mancos, River, McElmo Creek and San Juan River segments: 2b, 3b, 5b, 6b, 7b, 8b, 9, 10b, 14, 17, 20, 22
L.	Other Site-Specific Revisions
La Plata River, Mancos, River, McElmo Creek and San Juan River 2b: The discrepancy between the Recreation Use season and the E. coli standard season was corrected.  The fecal coliform standard was also deleted.  
Upper Dolores River segment 11: The typographical error in the Agriculture designated use was corrected.
M.	Tribally-Owned Lands
The Southern Ute Indian Tribe raised an issue with the wording of section 34.5(4).  The Commission deleted the phrase “in agreement with the Southern Ute and Ute Mountain Ute Indian Tribes”.  This section was added in 2001 and referred to a verbal staff level agreement at that time.
PARTIES TO THE RULEMAKING HEARING
1.	Trout Unlimited
2.	WildEarth Guardians
3.	National Park Service, Curecanti National Recreation Area
4.	Mountain Coal Company
5.	U.S. Energy Corp.
6.	Climax Molybdenum Company
7.	Gunnison County
8.	Gunnison County Stockgrowers Association, Inc.
9.	Homestake Mining Company of California
10.	Colorado Parks and Wildlife
11.	High Country Citizens’ Alliance
12.	Town of Crested Butte
13.	Upper Gunnison River Water Conservancy District
14.	Dolores Water Conservancy District
15.	Town of Hotchkiss
16.	Town of Olathe
17.	Town of Silverton
18.	Atlantic Richfield Company
19	City of Delta
20.	Environmental Protection Agency
21	R Squared, Inc.
22.	Wright Water Engineers, Inc.
23.	San Juan Citizens Alliance
24.	Colorado Sand and Gravel Association