DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT
WATER QUALITY CONTROL COMMISSION
5 CCR 1002-93
REGULATION #93 
Colorado's Section 303(d) List of Impaired Waters and Monitoring and Evaluation List
93.1	Authority
These regulations are promulgated pursuant to section 25-8-101 et seq C.R.S. as amended, and in particular, 25-8-202 (1) (a), (b), (i), (2) and (6); 25-8-203 and 25-8-204.
93.2	Purpose
This regulation establishes Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) and Colorado’s Monitoring and Evaluation List.  
(1)	The list of Water-Quality-Limited Segments Requiring TMDLs fulfills requirements of section 303(d) of the federal Clean Water Act which requires that states submit to the U.S. Environmental Protection Agency a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.
(2)	Colorado’s Monitoring and Evaluation List identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more factors, such as the representative nature of the data.  Water bodies that are impaired, but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution, are also placed on the Monitoring and Evaluation List.  This Monitoring and Evaluation list is a state-only document that is not subject to EPA approval.
93.3	Water Bodies Requiring TMDLs or Identified for Monitoring and Evaluation 
Only those segments where a Clean Water Section 303(d) Impairment has been determined require TMDLs.  For these segments, TMDLs are only required for those parameters that are identified as impairments.  Listings marked with an asterisk (*) are carryover from the 1998 303(d) List.  Consequently they are all high priority. 

WBID	Segment Description	Portion	Colorado’s Monitoring & Evaluation Parameter(s)	Clean Water Act Section 303(d) Impairment	303(d) Priority	
COAR	Arkansas River Basin	 		 	 	
COARFO01a	Fountain Creek and tributaries above Monument Creek	all		E. coli, Se 	H/L	
COARFO02a	Fountain Creek, Monument Creek to Hwy 47	all		E. coli 	H	
COARFO02b	Fountain Creek from Hwy 47 to the Arkansas River	all		Se, E. coli (May-October)	L/H 	
COARFO04	All tribs to Fountain Creek, which are not on National Forest or Air Force Academy Land	all		E. coli	H	
COARFO06	Monument Creek from National Forest to Fountain Creek	Below Mesa Road (for Se only)
All (for E. coli)		Se, E. coli (May-October)	L/H	
COARFO07a	Pikeview Reservoir, Willow Springs Ponds #1 and #2	Willow Springs Ponds #1 & #2		Aquatic Life Use (PCE FCA)	M	
COARLA01a	Arkansas River, Fountain Creek to Colorado Canal headgate	all		Se, SO4	L	
COARLA01b	Arkansas River, Colorado Canal headgate to John Martin Reservoir	all		 Se	L	
COARLA01c	Arkansas River, John Martin Reservoir to stateline	all		Se, U	L	
COARLA04	Apishapa River, Timpas Creek, Lorencito Canyon	all		Se	L	
COARLA04	Apishapa River, Timpas Creek, Lorencito Canyon	Timpas Creek		Fe(Trec)	H	
COARLA05a	Purgatoire River from source to I-25	all		Se	L	
COARLA05b	Trinidad Reservoir, Long Canyon Reservoir, and Lake Dorothey	Trinidad Reservoir	 	Aquatic Life Use (Hg FCA), D.O. (temperature)	H	
COARLA07	Purgatoire River, I-25 to Arkansas River	all	sediment	Se	L	
COARLA09a	Mainstem of Adobe Creek and Gageby Creek…	all		Se	L	
COARLA09a	Mainstem of Adobe Creek and Gageby Creek…	Horse Creek		Fe(Trec)	H	
COARLA09a	Mainstem of Adobe Creek and Gageby Creek…	Adobe Creek		E. coli	H	
COARLA09b	Apache Creek, Breckenridge Creek, Little Horse Creek, Bob Creek, Wildhorse Creek, Wolf Creek, Big Sandy Creek	all		Se	L	
COARLA09c	Rule Creek, Muddy Creek, Caddoa Creek, Clay Creek, Cat Creek…	As specified to right	Zn
(Rule Creek)	Fe(Trec), Se
(Chicosa Creek)	L	
COARLA10	Two Buttes Res., Two Buttes Pond, Hasty Lake, Holbrook Res., Burchfield Lake, Nee-Skah (Queens) Res., Adobe Creek Res., Neeso Pah Res., Nee Nosha Res., Nee Gronda Res.	Adobe Creek Res., Nee Gronda Res		Se	L	
COARLA11	John Martin Reservoir	all		Se	L	
COARLA12	Lake Henry, Lake Meredith	all		Se	L	
COARMA04a	Wildhorse Creek	all	NO2	E. coli	H	
COARMA06	St. Charles River and tributaries, CF&I diversion to Arkansas River	all	U	Se	L	
COARMA07	Greenhorn Creek, including all tributiaries, from source to Greenhorn Highline Diversion Dam; Graneros Creek; North Muddy Creek	all	Cu, Zn			
COARMA09	Greenhorn Creek, including tributaries, from Greenhorn Highline Diversion Dam to the St. Charles River	all	Se			
COARMA10	Sixmile Creek	all		Fe(Trec), Se	L	
COARMA12	Huerfano River, from Muddy Creek to the Arkansas River	all		Se	L	
COARMA14	Cucharas River, from Walsenburg PWS diversion to the outlet of Cucharas Reservoir	all		Se	L	
COARMA16	Huajatolla Reservoir, Diagre Reservoir, Walsenburg Lower Town Lake, Horseshoe Lake and Martin Lake (Ohem Lake)	Horseshoe Lake		Aquatic Life Use (Hg FCA)	H	
COARMA18a	Boggs Creek	all		Se, Zn, U	H	
COARUA08b	Iowa Gulch from ASARCO water supply intake to Paddock #1 Ditch (Iowa Ditch)	all		Cd, Pb, Zn	M	
COARUA10	Mainstem of Lake Creek and all tributaries, lakes and reservoirs from source to Arkansas River (including Twin Lakes Reservoir)	all, excluding Twin Lakes Reservoir		pH, D.O., Cu	H	
COARUA10	Mainstem of Lake Creek and all tributaries, lakes and reservoirs from source to Arkansas River (including Twin Lakes Reservoir)	Twin Lakes Reservoir	
Cu			
COARUA14b	Tributaries to the Arkansas River, from Pueblo Reservoir to Colorado Canal headgate	Teller Reservoir	Aquatic Life Use (Hg FCA)			
COARUA15	Grape Creek including De Weese Res., Texas, Badger, Hayden, Hamilton, Stout and Big Cottonwood Creeks, Newland Creek	De Weese Reservoir		D.O.	H	
COARUA20	Fourmile Creek and tributaries, Cripple Creek to Arkansas River	North Fork Wilson Creek below Independence Mine	As, Cu			
COARUA27	Mainstem of Eightmile Creek, including all tributaries, wetlands, lake and reservoirs, from the source to the mouth of Phantom  Canyon; Brush Hollow Reservoir	Brush Hollow Reservoir	pH	Aquatic Life Use (Hg FCA), D.O.	H	
COGU	Gunnison River Basin	 		 	 	
COGULG02	Gunnison River, Uncompaghre River to Colorado River	all	sediment	Se*	H	
COGULG04a	Tributaries to Gunnison River, Crystal Reservoir to Colorado River	all		Se	H	
COGULG04b	All lakes and reservoirs tributary to the Gunnison River and not on national forest lands from the outlet of Crystal Reservoir to the Colorado River	Juniata Reservoir		Aquatic Life Use (Hg FCA)	H	
COGULG04b	All lakes and reservoirs tributary to the Gunnison River and not on national forest lands from the outlet of Crystal Reservoir to the Colorado River	Jatz Bottomlands	Se			
COGULG04c	Red Rock Creek within Black Canyon of the Gunnison National Park	all		Se	H	
COGULG07	Surface, Ward, Tongue, Youngs, and Kiser Creeks not on USFS land	Tongue Creek, Ward Creek	Se			
COGULG07	Surface, Ward, Tongue, Youngs, and Kiser Creeks not on USFS land	Surface Creek	Fe (Trec)			
COGULG08	Tributaries to Gunnison River, Kannah Creek	Kannah Creek below USGS station 09152000		Se	H	
COGULG09	Fruitgrowers Reservoir	all		D.O.	H	
COGULG11a 	Tributaries to the Smith Fork	Lunch Creek	sediment			
COGUNF03	North Fork of the Gunnison from Black Bridge above Paonia to the confluence within the Gunnison	all		Se	H	
COGUNF05	Hubbard, Terror, Minnesota and Leroux Creeks from USFS boundary to N. Fork. Mainstem of Jay Creek and mainstem and tribs of Roatcap Creek to the N. Fork	Leroux Creek, Jay Creek,		Se*	H	
COGUNF06a	Tributaries to the North Fork of the Gunnison River not on USFS lands	Short Draw		Se	H	
COGUNF06a	Tributaries to the North Fork of the Gunnison River not on USFS lands	Coal Gulch, Hawksnest Creek, Gribble Gulch	Fe(Trec)			
COGUNF06b	Bear Creek, Reynolds Creek, Bell Creek, McDonald Creek, Cottonwood Creek, Love Gulch, Cow Creek, Dever Creek, German Creek, Miller Creek, Stevens Gulch, Big Gulch, Stingley Gulch and Alum Gulch not on national forest lands from the source to the North Fork of the Gunnison River	Big Gulch	Se 			
COGUNF06b	Bear Creek, Reynolds Creek, Bell Creek, McDonald Creek, Cottonwood Creek, Love Gulch, Cow Creek, Dever Creek, German Creek, Miller Creek, Stevens Gulch, Big Gulch, Stingley Gulch and Alum Gulch not on national forest lands from the source to the North Fork of the Gunnison River	Cottonwood Creek	Fe(Trec)	Se	H	
COGUSM02	Tributaries to the San Miguel River from the source to Leopard Creek	Bilk Creek	Cd			
COGUSM03a	San Miguel River, Bridal Veil & Ingram Creek to Marshall Creek	below Idarado Mine	Cd			
COGUSM06a	Ingram Creek, source to San Miguel River	all	Cd, Mn			
COGUSM06b	Marshall Creek, source to San Miguel River	all	Cd, Cu, Pb			
COGUUG07	Slate River from source to Coal Creek	Below Oh-Be-Joyful Creek	Cd	Zn(sculpin)	H	
COGUUG08	Slate River, Coal Creek to East River 	all		Cd, Zn	H	
COGUUG10	Oh-Be-Joyful Creek and tributaries from wilderness to Slate River	all		Cd, Cu, Pb, Zn	H	
COGUUG11	Coal Creek from Elk Creek to Crested Butte water supply intake, plus Elk Creek	all		Cd, Pb, Zn	H	
COGUUG12	Coal Creek and tributaries from Crested Butte water supply intake to Slate River	Coal Creek		Cd, Zn	H	
COGUUG16	Ohio Creek and tributaries source to Gunnison River	all	Zn(sculpin)			
COGUUG17	Antelope Creek and tributaries source to Gunnison River	all	D.O.			
COGUUG18	Tomichi Creek source to Gunnison River	all	E. coli			
COGUUG29a	Lake Fork of the Gunnison River and tributaries from source to Blue Mesa Reservoir	Deadman Gulch		pH, Cd, Cu, Mn, Zn	H	
COGUUG30	Henson Creek mainstem and tribs	all		Cd, Zn(sculpin)	H	
COGUUG31	Palmetto Gulch	all	Cu	Cd, Zn	M	
COGUUG32	North Fork of Henson Creek and tributaries from source to Henson Creek	all	Pb, Zn(sculpin)			
COGUUN04a	Uncompaghre River, HWY 90 to La Salle Road	all	sediment			
COGUUN04b	Uncompaghre River, La Salle Road to Confluence Park	all	sediment	Se*	H	
COGUUN04c	Uncompaghre River, Confluence Park to Gunnison River	all	sediment	Se*	H	
COGUUN07	Gray Copper Gulch from source to Red Mountain Creek	all	Fe(Trec)			
COGUUN08	Mineral Creek, source to Uncompahgre River	all	Cd, Cu, Zn			
COGUUN09	Canyon Creek, Imogene Creek, Sneffles Creek	all	Zn			
COGUUN09	Canyon Creek, Imogene Creek, Sneffles Creek	Canyon Creek	Pb			
COGUUN10	All tributaries to the Uncompahgre River from Dexter Creek to the South Canal	Alkali Creek	Se			
COGUUN11	Coal, Dallas, Cow, Billy, Onion, Beaton, Beaver and Pleasant Valley Creeks	Billy Creek, Onion Creek	Se			
COGUUN12	Tributaries to Uncompahgre River, South Canal to Gunnison River	all		Se	H	
COGUUN14	Sweitzer Lake	all	D.O.	Se*	H	
COGUUN15b	Dry Creek from East and West Forks to Coalbank Canyon Creek	Dry Creek Watershed	sediment			
COGULD01	Dolores River from Bradfield Ranch to Little Gypsum Valley bridge	all		Fe(Trec)	H	
COGULD02	Dolores River from Little Gypsum Valley bridge to Colorado/Utah border	all		Fe(Trec)	H	
COLC	Lower Colorado River Basin	 		 	 	
COLCLC01	Colorado River, Roaring Fork River to Rifle Creek	all	sediment			
COLCLC02a	Colorado River, Rifle Creek to Rapid Creek	all	sediment			
COLCLC02b	Colorado River, Rapid Creek to Gunnison River	Humphrey Backwater area 	
	Se	M	
COLCLC02b	Colorado River, Rapid Creek to Gunnison River	all	sediment, Se			
COLCLC03	Colorado River, Gunnison River to state line	all		Se	M	
COLCLC04a	Tributaries to Colorado River, Roaring Fork to Parachute Creek except for specific segments	all		Se	M	
COLCLC04a	Tributaries to Colorado River, Roaring Fork to Parachute Creek except specific segments	Alkali Creek	E. coli, Cu, Fe(Trec), Pb, Zn			
COLCLC04b	South Canyon Hot Springs	all	D.O., Pb			
COLCLC04c	South Canyon Creek	all	Cu, Se, E. coli (May-Oct)			
COLCLC10	East Rifle Creek, West Rifle Creek and Rifle Creek, including tributaries from Rifle Gap to the Colorado River	West Rifle Creek	Fe(Trec)			
COLCLC10	East Rifle Creek, West Rifle Creek and Rifle Creek, including tributaries from Rifle Gap to the Colorado River	all	E. coli	Se	L	
COLCLC13b	Tributaries to Colorado River from Government Highline Canal Diversion to Salt Creek	Salt Creek		sediment	L	
COLCLC13b	Tributaries to Colorado River from Government Highline Canal Diversion to Salt Creek except specific segments	all		Se	M	
COLCLC13b	Tributaries to Colorado River from Government Highline Canal Diversion to Salt Creek except specific segments	Adobe Creek 		E. coli, Fe(Trec)	H	
COLCLC13b	Tributaries to Colorado River, Government Highline Canal to Salt Creek except specific segments	Indian Wash	Fe(Trec)			
COLCLC13c	Walker Wildlife Area Ponds	all		Se	M	
COLCLC14b	Clear Creek from Tom Creek to Roan Creek. Roan Creek, including tributaries from Clear Creek to Kimball Creek	all	E. coli, Fe(Trec)			
COLCLC14c	Mainstem of Roan Creek including all tributaries from Kimball Creek to the Colorado River	Dry Fork		Se	L	
COLCLC15	Plateau Creek, including tributaries from source to Hwy 330 Bridge.  Kimball Creek, Grove Creek, Big Creek, Cottonwood Creek, Bull Creek, Spring Creek, Coon Creek and Mesa Creek.	all 	Fe(Trec), Se			
COLCLC19	Lakes and reservoirs tributary to the Colorado River, Parachute Creek to the Colorado/Utah border.	See specifics to the right.	Se 
(Maggio Pond, Peters Ponds 1, 2, 3, & 4)	Se 
(West Pond Orchard Mesa Wildlife Area)	H	
COLCLC20	Rifle Gap Reservoir, Harvey Gap Reservoir and Vega Reservoir	Rifle Gap Reservoir		Aquatic Life Use (Hg FCA)	H	
COLCLY02	Yampa River, Elkhead Creek to Green River	all	sediment	Fe(Trec)	H	
COLCLY03c	Milk Creek and tributaries from CR 15 to the Yampa	Stinking Gulch	Cu, Fe(Trec), Se, Zn			
COLCLY03e	Good Spring Creek above Wilson Reservoir	Wilson Creek	Se			
COLCLY05	Fortification Creek from North and South Fork to the Yampa River	all		Se	L	
COLCLY07	Little Bear Creek, including all tributaries from source to Dry Creek	all	Cu, Zn			
COLCLY16	Little Snake River from Power Wash to the Yampa River	all	sediment			
COLCLY18	Slater Creek, including tributaries from source to Second Creek	all	E. coli, Fe(Trec), Se			
COLCLY22c	Vermillion Creek from Hwy 318 Talmantes Creek to Green River	all	E. coli, Fe(Trec)			
COLCWH07	Mainstem of the White River from a point above the confluence with Miller Creek to a point immediately above the confluence with Piceance Creek	White River, blw Meeker	Cu			
COLCWH09a	Tributaries to the White River from North and South Forks to Peceance Creek not within the boundary of National Forest lands except segments 9b and 10b.	Strawberry Creek	Cu, Zn			
COLCWH09d	Sulphur Creek and tributaries from source to White River. Flag Creek and tributaries from the East Fork of Flag Creek to the White River.	all		Se	L	
COLCWH10b	Mainstem of Big Beaver Creek, Miller Creek, and North Elk Creek, including tributaries, from their boundaries with the National Forest Lands to their confluences with the White River.  Mainstem of Coal Creek, including all tributaries from the source to the confluence with the White River 	Coal Creek	Se			
COLCWH11	Rio Blanco Reservoir	Rio Blanco Reservoir	pH			
COLCWH16	All tributaries to Piceance Creek, including all wetlands, lakes and reservoirs, from the source to the confluence with the White River	Ryan Gulch	E. coli			
COLCWH22	Tributaries to White River, Douglas Creek to Colorado/Utah border	West Evacuation Wash, Douglas Creek		sediment	L	
COLCWH23	Mainstem of East Douglas Creek and West Douglas Creek including all tributaries from their sources to the confluence	East Douglas Creek	Fe(Trec)			
CORG	Rio Grande River Basin					
CORGAL02	Alamosa River, from source to confl with Alum Creek	Tribs to lower Iron Ck		pH, Cu, Zn, Fe(Trec)	H	
CORGAL02	Alamosa River, from source to confluence with Alum Creek	All, except for the tributaries to Lower Iron Creek	pH, Fe(Trec)			
CORGAL03b	Alamosa River, from Wightman Fork to Fern Creek	Above Jasper Creek	Se	Cd	H	
CORGAL03d	Alamosa River, from Ranger Creek to Terrace Res.	all		Al	H	
CORGAL08	Terrace Reservoir	all		Fe(Trec)	M	
CORGAL11	La Jara Creek including tributaries, wetlands, lakes and reservoirs from source to Hot Creek	La Jara Reservoir	pH, Cu, Se, Zn	D.O.	H	
CORGAL13	Hot Creek from source to La Jara Creek	all		Fe(Trec)	H	
CORGAL14	Conejos River including tributaries, wetlands, lakes, and reservoirs from source to Fox Creek	Platoro Reservoir	pH			
CORGAL20	Rio Grande, tribs within the Rio Grande Forest	all	pH, Cu, Cd, Fe(Trec), Mn, Zn			
CORGCB02	La Garita Creek, source to 38 Rd, Carnero Creek, source to 42 Rd	La Garita Creek	Fe(Trec)			
CORGCB05	San Luis Creek, from Piney Creek to San Luis Lake	Lower San Luis Creek	D.O.			
CORGCB06	San Luis Lake	all		NH3, Fe(Trec)	H	
CORGCB08	Kerber Creek, source to abv Cocomongo Mill Site, Squirrel Creek from source to abv Bear Creek. Brewery Creek from source to Elkhorn Gulch	Squirrel Creek	Cd, Cu, Zn, Fe(Trec)			
CORGRG02	Rio Grande River, source to Willow Creek	South Clear Creek	Fe(Trec)			
CORGRG04	Rio Grande River, Willow Creek to Alamosa County line	Del Norte to county line		Cu	H	
CORGRG05	All tributaries to the Rio Grande River, abv Willow Creek to Del Norte	Nelson Creek	Cd, Cu, Pb, Mn, Zn, pH 			
CORGRG07	West Willow Creek, East Willow Creek, Willow Creek and tributaries	Nelson Creek, West Willow Creek below Nelson Creek to East Willow Creek		pH	H	
CORGRG09	South Fork of Rio Grande, from source to Rio Grande	Beaver Creek Reservoir	D.O.			
CORGRG13	Rio Grande River, Conejos County Road G to Colorado/New Mexico border	all	sediment			
CORGRG27	Smith Reservoir	Smith Reservoir	pH			
CORGRG28	Rito Seco, from source to Salazar Reservoir	Upper Rito Seco blw Battle Mtn		E. coli	H	
CORGRG30	Culebra Creek, including all tributaries, lakes, and reservoirs from HWY 159 to the Colorado/New Mexico border	Sanchez Reservoir		D.O.	H	
COSJ	San Juan River Basin	 		 	 	
COSJDO04b	McPhee Reservoir and Summit Reservoir	McPhee Reservoir		Aquatic Life Use(Hg* FCA)	H	
COSJLP03a	All Tributaries to the La Plata River from Hay Gulch to the Southern Ute Indian reservation boundary	Cherry Creek		Fe(Trec)	H	
COSJLP04a	Mancos River and tributaries above HWY 160	E. Mancos River		Cu	H	
COSJLP08a	Tributaries to McElmo Creek 	all	Fe(Trec)			
COSJLP11	Narraguinnep, Puett, and Totten Reservoir	Narraguinnep Reservoir, Totten Reservoir		Aquatic Life Use(Hg* FCA)	H	
COSJPI06a	Tributaries to the Piedra River	Stollsteimer Creek above Southern Ute Boundary	sediment			
COSJPN03	Vallecito Reservoir	Vallecito Reservoir		Aquatic Life Use (Hg FCA)	H	
COSJSJ03	Little Navajo River, including tributaries from the San Juan-Chama diversion to the San Juan River	all	E. coli			
COSJSJ06a	San Juan River from Fourmile Creek to Southern Ute Indian Reservation.  Mill Creek from source to San Juan River.  Echo Canyon Reservoir.	Echo Canyon Reservoir		Aquatic Life Use (Hg FCA)	H	
COSJSJ08	Navajo Reservoir	Navajo Reservoir	Aquatic Life Use (Hg FCA)			
COSP	South Platte River Basin	 		 	 	
COSPBD01	Mainstem of Big Dry Creek, including all tributaries, lakes, reservoirs and wetlands, from the source to the confluence with the South Platte River	all		E. coli, 
Se (11/1 thru 3/31)	H/L	
COSPBD02	Standley Lake	all	D.O.			
COSPBE01c	Bear Creek Reservoir	all	D.O.	Chl-a, phosphorus	M	
COSPBE02	Bear Creek below Bear Creek Reservoir to South Platte River	below Kipling Parkway (CO 390)		E. coli (May-Oct)	H	
COSPBE05	Swede, Kerr, Sawmill, Troublesome and Cold Springs Gulches and Cub Creek	Swede/Kerr Gulch		E. coli	L	
COSPBO01	All tribs to Boulder Creek within the Indian Peaks Wilderness Area	all	Pb, Zn			
COSPBO02a	Mainstem of Boulder Creek,from the boundary of the Indian Peaks Wilderness Area to a point immediately below the confluence with North Boulder Creek	all	Cd, Cu			
COSPBO02b	Mainstem of Boulder Creek, from below the confluence with North Boulder Creek to above the confluence with South Boulder Creek	below 13th Street in Boulder		E. coli	H	
COSPBO02b	Mainstem of Boulder Creek, from below the confluence with North Boulder Creek to above the confluence with South Boulder Creek	all	
Cd, Cu			
COSPBO03	Mainstem of Middle Boulder Creek from source to the outlet of Barker Reservoir	all	Cd, Cu			
COSPBO04a	South Boulder Creek and tributaries from source to outlet of Gross Reservoir	Gamble Gulch		Cd	H	
COSPBO07b	Coal Creek, HWY 36 to Boulder Creek	all		E. coli	H	
COSPBO08	All tribs to South Boulder Creek and all tribs to Coal Creek	Rock Creek	E. coli	Se	M	
COSPBO09	Mainstem of Boulder Creek, from South Boulder Creek to Coal Creek	all	Aquatic Life, Cd, As			
COSPBO10	Boulder Creek, Coal Creek to St. Vrain Creek	all	Aquatic Life, Cd	E. coli	H	
COSPBO14	Lakes and reservoirs tributary to Boulder Creek from source to South Boulder Creek.	Barker Reservoir	D.O., Cd, Cu			
COSPBT01	Mainstem of the Big Thompson River including all tributaries and wetlands, which are within Rocky Mountain National Park, except for specific listings in Segment 2	all		Cu	H	
COSPBT02	Big Thompson River and tribs, RMNP to Home Supply Canal diversion	Fish Creek below Marys Lake		pH	H	
COSPBT02	Big Thompson River and tribs, RMNP to Home Supply Canal diversion	all	Sulfide	Cu, Cd, Zn, temperature	H	
COSPBT03	Mainstem of the Big Thompson River from the Home Supply Canal diversion to the Big Barnes Ditch diversion.	all		Cu	M	
COSPBT04a	Mainstem of the Big Thompson from the Big Barnes Ditch diversion of the Greeley-Loveland Canal diversion.	all		Se	M	
COSPBT04b	Big Thompson River, Greeley-Loveland Canal diversion to CR11H	all		Se	M	
COSPBT05	Big Thompson River, I-25 to S. Platte River	all		Se	L	
COSPBT06	All tributaries to the Big Thompson River, from Home Supply Canal to the confluence with the South Platte River.	all		Cu	M	
COSPBT06	All Tribs to the Big Thompson River, from Home Supply Canal to the confluence with the South Platte River.	Dry Creek	E. coli			
COSPBT07	Mainstem of the North Fork of the Big Thompson from RMNP to confluence with Big Thompson	North Fork of Big Thompson		Cu	H	
COSPBT08	Mainstem of the Little Thompson River, from source to the Culver Ditch diversion.	all		temperature, D.O	H	
COSPBT09	Little Thompson River, Culver Ditch to Big Thompson River	all		Cu, Se, E. coli (May-October), Aquatic Life Use	M/L/H/M	
COSPBT10	Tributaries to the Little Thompson River	Big Hollow		Se	L	
COSPBT11	Carter Lake	all	Cu, As	Aquatic Life Use (Hg FCA)	H	
COSPBT12	Lake Loveland, Horseshoe Lake, Boyd Lake	Boyd Lake		Aquatic Life Use (Hg FCA)	H	
COSPBT12	Lake Loveland, Horseshoe Lake, Boyd Lake	all	D.O.			
COSPBT14	Welch Reservoir, Lonetree Reservoir, Boedecker Lake, Lon Hagler Reservoir	Lon Hagler Reservoir and Lonetree Reservoir	D.O.			
COSPBT16	Lakes and reservoirs tributary to the Big Thompson from RMNP to Home Supply Canal diversion.	Lake Estes	 Pb, As	Cu	H	
COSPCH02	Cherry Creek Reservoir	all	D.O.			
COSPCH03	Mainstem of Cherry Creek from Cherry Creek Reservoir to the South Platte.	all		E. coli, Se	H/L	
COSPCH04	Tributaries to Cherry Creek 	Goldsmith Gulch, Cottonwood Creek		Se	L	
COSPCH06	Lakes and reservoirs in the Cherry Creek watershed within the City and County of Denver.	Lollipop Lake	Se			
COSPCL02a	Mainstem of Clear Creek from Silver Plume to West Fork Clear Creek.	all		Cd	H	
COSPCL02b	Mainstem of Clear Creek from West Fork Clear to Mill Creek.	all		Cd, Zn	H	
COSPCL02c	Mainstem of Clear Creek from Mill Creek to Argo Tunnel.	all		Cd	H	
COSPCL03a	Mainstem of S. Clear Creek	all		Cu	H	
COSPCL03b	Leavenworth Creek	all		Cu	M	
COSPCL06	All tributaries to West Clear Creek.	Mad Creek	pH	Zn	M	
COSPCL06	All tributaries to West Clear Creek.	Hoop Creek	Cd, Pb, Zn			
COSPCL09a	Fall River & tributaries, source to Clear Creek	Fall River	Zn, D.O.			
COSPCL09a	Fall River & tributaries, source to Clear Creek	Silver Creek		Cu, Pb	H	
COSPCL09b	Trail Creek & tributaries, source to Clear Creek 	all		Cd, pH	H	
COSPCL11	Clear Creek, Argo Tunnel to Farmers Highline Canal	all		Cd	H	
COSPCL13b	N. Clear Creek & tributaries, lowest water supply intake to Clear Creek	Mainstem of N. Clear Creek		Cd	M	
COSPCL14b	Clear Creek, Denver Water conduit #16 to Youngfield St.	all	Mn	Aquatic Life Use, organic sediment	L	
COSPCL15	Clear Creek, Youngfield St. to S. Platte River	all	Pb	E. coli (May-October), Aquatic Life Use, organic sediment	H/L/L	
COSPCL17a	Arvada Reservoir	all		D.O. (temperature)	H	
COSPCL18a	Ralston Creek and tributaries below Arvada Reservoir	Ralston Creek		E. coli	H	
COSPCP06	Mainstem of the North Fork of the Cache La Poudre River, including all tribs from source to Halligan Res.	all	Cu			
COSPCP07	North Fork of the Cache la Poudre from Halligan Reservoir to the Cache la Poudre.	all		Pb, Cd	M	
COSPCP08	All tributaries to the North Fork of the Cache La Poudre from Halligan Reservoir to the Cache La Poudre.	all	E. coli			
COSPCP09	Rabbit Creek and Lone Pine Creek	all	Cd, Pb			
COSPCP10	Cache la Poudre River, Monroe Canal to Shields Street	all	Aquatic Life Use	Cu, temperature	M	
COSPCP11	Mainstem of the Cache la Poudre River from Shields Street in Ft. Collins to a point immediately above the confluence with Boxelder Creek.	all		Se	L	
COSPCP12	Cache la Poudre River, Box Elder Creek to S. Platte River	all		Se, E. coli (May-October)	L/H	
COSPCP13a	All tributaries to the Cache la Poudre River, including all wetlands, from the Monroe Gravity Canal to the confluence with the South Platte River.	all		Se	L	
COSPCP13a	All tributaries to the Cache la Poudre River, including all wetlands, from the Monroe Gravity Canal to the confluence with the South Platte River.	Spring Creek and Fossil Creek		E. coli (May-Oct)	H	
COSPCP13b	Boxelder Creek from source to the Cache la Poudre River	all		Se	L	
COSPCP14	Horsetooth Reservoir	all	Cu, As, D.O.	Aquatic Life Use (Hg FCA)	H	
COSPCP20	Lakes and reservoirs tributary to the North Fork of the Cache la Poudre from Halligan Reservoir to the Cache la Poudre River.	Seaman Reservoir		D.O.	M	
COSPLA02a	Mainstem of Laramie River from the source to the NF boundary.	all	pH			
COSPLS01	Mainstem of the South Platte from the Weld/Morgan County line to the Colorado/Nebraska border.	all	Aquatic Life Use	Se, Mn	M	
COSPLS02b	Tributaries to S Platte River, Beaver Creek, Bijou Creek and Kiowa Creek	Beaver Creek		 Se, E. coli 	H	
COSPLS03	Jackson, Prewitt, North Sterling, Jumbo, Riverside, Empire and Vancil Reservoirs	North Sterling Reservoir	D.O.			
COSPLS03	Jackson, Prewitt, North Sterling, Jumbo, Riverside, Empire and Vancil Reservoirs	North Sterling, Jackson and Jumbo Reservoirs	Se, pH			
COSPMS01a	South Platte River from Big Dry Creek to St. Vrain Creek	all		E. coli	H	
COSPMS01b	South Platte River from St. Vrain Creek to Weld/Morgan County Line	all		Se	L	
COSPMS04	Barr Lake and Milton Reservoir	all		pH, NH3	M/L	
COSPMS04	Barr Lake and Milton Reservoir	Barr Lake	D.O.			
COSPMS04	Barr Lake and Milton Reservoir	Milton Reservoir		D.O.	L	
COSPMS07	All lakes and reservoirs trib to the South Platte River below Big Dry Creek to Weld/Morgan County Line	Horse Creek Reservoir	D.O.	pH, NH3	L	
COSPMS07	All lakes and reservoirs trib to the South Platte River below Big Dry Creek to Weld/Morgan County Line	Prospect Lake		D.O., pH, NH3	M	
COSPRE04	Mainstem of Arikaree River from the confluence of the North and South Forks to the Kansas border.	all		 E. coli	H	
COSPRE05	Mainstem of the Black Wolf Creek from the source to the confluence with the Arikaree River.	all	E. coli, Se			
COSPSV02a	Mainstem of St. Vrain from Indian Peaks Wilderness Area and RMNP to eastern boundary of Roosevelt Ntl Forest	all		Zn	H	
COSPSV02b	St. Vrain Creek, including all tributaries from the eastern boundary of Roosevelt National Forest to Hygiene Road	all		Cu, temperature	H	
COSPSV03	St. Vrain Creek, Hygiene Rd. to S. Platte River	all	Aquatic Life Use			
COSPSV04a	Left Hand Creek, from source to blw confluence with James Creek	pH, Cu, Zn (Hwy 72 to James Ck)		pH, Cu, Zn 	M	
COSPSV04b	James Creek, Little James Creek	Little James Creek 		Cu, Pb	M	
COSPSV04c	Left Hand Creek from James Creek to HWY 36	all		Cu, As	H	
COSPSV06	Tributaries to the St Vrain River	Dry Creek		E. coli	H	
COSPSV06	Tributaries to the St Vrain River	all		Se	L	
COSPSV07	Boulder Resevoir, Coot Lake, Left Hand Valley Reservoir	Boulder Reservoir	D.O.			
COSPSV09	All lakes and reservoirs tributary to St. Vrain from sources to Hygiene Road.	Union Reservoir	D.O.			
COSPSV13	All lakes and reservoirs tributary to Left Hand Creek from Hwy 36 to St. Vrain Creek.	Lake Thomas	D.O.			
COSPUS02a	Tributaries to S. Platte River, source to Tarryall Creek	Salt Creek d/s of N. Fork, on USFS Land	temperature			
COSPUS02a	Tributaries to S. Platte River, source to Tarryall Creek	Twin Creek, on USFS Land	temperature			
COSPUS02b	Mosquito Creek from South Mosquito Creek to the Middle Fork of the South Platte.	all		Cd	H	
COSPUS02c	South Mosquito Creek from the source to the confluence with Mosquito Creek and No Name Creek from  the source to the confluence with Mosquito Creek	No Name Creek		Cd, Zn	H	
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N.Fk.S.Platte R	Trout Creek and tributaries on USFS property		sediment*	M	
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N.Fk.S.Platte R	Pine Creek		As	H	
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N. Fk. S. Platte River	Pine Creek, on USFS Land	sediment			
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N.Fk.S.Platte R	Fourmile Creek	sediment	Fe(trec), As, Hg	H	
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N.Fk.S.Platte R	Sugar Creek, on USFS Land	sediment			
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N. Fk. S. Platte River	Hawkins Gulch	Cd, Se			
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N. Fk. S. Platte River	Horse Creek	D.O., Fe(trec)			
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N. Fk. S. Platte River	West Creek	As, Hg			
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N. Fk. S. Platte River	Goose Creek	D.O.			
COSPUS03	Tributaries to S.Platte River, Tarryall Creek to N. Fk. S. Platte River	Trail and Wigwam Creeks	Fe(trec)			
COSPUS04	N. Fk. S. Platte River & Tributaries, source to S.Platte R	Hall Valley area to Geneva Ck		pH	H	
COSPUS05a	Geneva Creek above Scott Gomer Creek	all		Cd, Cu, Zn	H	
COSPUS05b	Geneva Creek, Scott Gomer Creek to N. Fork S. Platte River	all		Cd	H	
COSPUS05c	Gooseberry Gulch and all tributaries from source to confluence with Elk Creek.	Unnamed Tributary to Gooseberry Creek		NH3	M	
COSPUS07	Tributaries to the South Platte from the North Fork of the South Platte to the outlet of Chatfield Reservoir.	Willow Creek	Fe(Trec), Se			
COSPUS09	Mainstem of Bear Creek, including all tributaries and wetlands from the source to the inlet of Perry Park Reservoir (Douglas County).	Bear Creek	D.O.			
COSPUS11a	Tributaries to East Plum Creek which are not on national forest lands.	all	pH, Fe(Trec)			
COSPUS11b	Tributaries to W. Plum Creek, not on USFS Land	Spring Creek, Bear Creek	Aquatic Life Use			
COSPUS12	Garber and Jackson Creeks	Jackson Creek	Pb			
COSPUS14	S. Platte River	all		As	H	
COSPUS15	S. Platte River, Burlington Ditch to Big Dry Creek	all		E. coli	H	
COSPUS15	S. Platte River, Burlington Ditch to Big Dry Creek	Burlington Ditch to Clear Creek		Cd	H	
COSPUS16a	Sand Creek	all		Se, E. coli	L/H	
COSPUS16b	Aurora Reservoir	all	D.O.			
COSPUS16c	Tributaries to S. Platte River, Chatfield Reservoir to Big Dry Creek except specific listings	all		Se	L	
COSPUS16c	Tributaries to S. Platte River, Chatfield Reservoir to Big Dry Creek except specific listings	Westerly Creek, Dry Gulch	
	E. coli	H	
COSPUS16c	Tributaries to S. Platte River, Chatfield Reservoir to Big Dry Creek except specific listings	Weir Gulch	E. coli			
COSPUS16c	Tributaries to S. Platte River, Chatfield Reservoir to Big Dry Creek except specific listings	Harvard, Harvard West, and Lakewood Gulches		E. coli
(May-October)	H	
COSPUS17a	Washington Park Lakes, City Park Lake, Rocky Mountain Lake, Berkeley Lake	Berkeley Lake, Rocky Mountain Lake		Aquatic Life Use (Hg FCA)	H	
COSPUS17a	Washington Park Lakes, City Park Lake, Rocky Mountain Lake, Berkeley Lake	Rocky Mountain Lake	pH, Cu			
COSPUS17a	Washington Park Lakes, City Park Lake, Rocky Mountain Lake, Berkeley Lake	Ferril Lake, Smith Lake	pH			
COSPUS17a	Washington Park Lakes, City Park Lake, Rocky Mountain Lake, Berkeley Lake	Grasmere Lake	Cu			
COSPUS17a	Washington Park Lakes, City Park Lake, Rocky Mountain Lake, Berkeley Lake	Berkeley Lake		D.O., As	L	
COSPUS17a	Washington Park Lakes, City Park Lake, Rocky Mountain Lake, Berkeley Lake	Duck Lake	pH, NH3	D.O.	M	
COSPUS17b	Sloan’s Lake	all	Fe(Trec)	D.O.	L	
COSPUS19	Lakes and reservoirs tributary to the Upper South Platte River from headwaters to Chatfield Reservoir.	Tarryall Reservoir, Cheesman Reservoir, Elevenmile Reservoir, Spinney Mountain Reservoir	D.O.			
COSPUS22	Lakes and reservoirs tributary to the Upper South Platte River from Chatfield Reservoir to Big Dry Creek.	Marston Reservoir, Quincy Reservoir 	D.O.			
COSPUS23	Lakes and reservoirs in the Upper South Platte watershed within the City and County of Denver.	Barnum Lake		E. coli, D.O.	L	
COSPUS23	Lakes and reservoirs in the Upper South Platte watershed within the City and County of Denver.	Vanderbilt Lake	D.O.			
COSPUS23	Lakes and reservoirs in the Upper South Platte watershed within the City and County of Denver.	Overland Lake, Parkfield Lake, Houston Lake, Aqua Golf Lake	pH			
COSPUS23	Lakes and reservoirs in the Upper South Platte watershed within the City and County of Denver.	Garfield Lake, Harvey Lake, Aqua Golf Lake	Fe(trec)			
COSPUS23	Lakes and reservoirs in the Upper South Platte watershed within the City and County of Denver.	Garfield Lake, Harvey Lake, Parkfield Lake, Houston Lake		D.O.	M	
COUC	Upper Colorado River Basin	 		 	 	
COUCBL04a	All direct tributaries to Dillon Reservoir and all tributaries and wetlands in the Blue River drainage above Dillon Reservoir.	all	Cd, Zn			
COUCBL12	Illinois Gulch and Fredonia Gulch	Illinois Gulch		Cd 	M	
COUCBL20	Mainstem of Elliott Creek and Spruce Creek including all tributaries and wetlands from their sources to the confluence with the Blue River	Spruce Creek	Fe(Trec)			
COUCEA05c	Eagle River, Martin Creek to Gore Creek	all		Cd	H	
COUCEA06	Tributaries to Eagle River, Belden to Lake Creek, except specific segments	Black Gore Creek, adjacent to I-70		sediment	H	
COUCEA10a	All tributaries to the Eagle River from Lake Creek to the Colorado River.	Eby Creek	Se			
COUCNP01	Tribs to the N Platte & Encampment Rivers w/in Wilderness Areas	South Fork Big Creek	Cu, E. coli			
COUCNP04a	All tributaries to the North Platte River except those tributaries in segments 1, 4b, 6, 7a and 7b.	Canadian River	Fe(Dis), 
E. coli			
COUCNP04a	All tributaries to North Platte River except those tributaries in segments 1, 4b, 6, 7a and 7b	Grizzly Creek, Little Grizzly Creek	Aquatic Life Use			
COUCNP04a	All tributaries to North Platte River except those tributaries in segments 1, 4b, 6, 7a and 7b	Little Grizzly Creek	E. coli, Fe(Trec)			
COUCNP04a	All tributaries to North Platte River except those tributaries in segments 1, 4b, 6, 7a and 7b	Lake Creek	pH, Fe(Trec)			
COUCNP04b	Mainstem of the Illinois and Canadian Rivers, including all tributaries of the Illinois
from Indian Creek to Michigan River  except for specific listings in Segments 7a and 7b, and all tribs of Canadian entering the mainstem from the Southwest.	Illinois River		Fe (Trec)	M	
COUCNP07b	Government Creek, Spring Creek	Spring Creek		D.O.	M	
COUCNP09	All lakes and reservoirs tributary to the North Platte and Encampment Rivers 
	Lake John, North Delaney Lake	pH			
COUCRF03a	Roaring Fork including all tributaries and wetlands from Hunter Creek to the Colorado River except segments 3b through 10	Capitol Creek	Se			
COUCRF03b	Red Canyon Creek including all tributaries and wetlands from the source to the Roaring Fork except Landis Creek from source to Hopkins Ditch Diversion	Landis Creek	Fe(Trec)			
COUCRF10	Thompson Creek including all tributaries and wetlands from the source to the Crystal River	Thompson Creek	Fe(Trec)			
COUCUC03	Mainstem of the Colorado River from Lake Granby to the Roaring Fork River.	From 578 Road Bridge to just above the confluence with the Blue River		Temperature	H	
COUCUC04	Tributaries to the Colorado River from Lake Granby to the Roaring Fork River which are on National Forest lands.	Ranch Creek		Temperature	H	
COUCUC05	Lakes and Reservoirs tributary to the Colorado River from RMNP/ANRA to the Roaring Fork not on National Forest	Wolford Mountain Reservoir	D.O.			
COUCUC06b	Mainstem of unnamed tributary from the headwaters to Willow Creek Reservoir Road	all	D.O.			
COUCUC07a	All tribs to the Colorado River, including wetlands from a point abv the confluence with the Blue River to blw confluence with the Roaring Fork, which are not on National Forest Lands except specific listings in segment 7b.	Alkali Slough		Fe (Trec), Se	L	
COUCUC07a	All tribs to the Colorado River, including wetlands from a point abv the confluence with the Blue River to blw confluence with the Roaring Fork, which are not on National Forest Lands except specific listings in segment 7b.	Muddy Creek and tribs
	Temperature			
COUCUC07b	Muddy Creek from Wolford Mountain Reservoir.  Rock Creek, Deep Creek, Sheephorn Creek Sweetwater Creek and Piney River.  	Muddy Creek from Wolford Mountain Reservoir to Cow Gulch	Temperature			
COUCUC07b	Muddy Creek from Wolford Mountain Reservoir.  Rock Creek, Deep Creek, Sheephorn Creek Sweetwater Creek and Piney River.  	Muddy Creek from Cow Gulch to the Colorado River		Temperature	H	
COUCUC10c	Mainstem of the Fraser River from Hammond Ditch to the confluence with the Colorado River.	all		Temperature	L	
COUCUC10c	Mainstem of the Fraser River, from the Hammond Ditch to the confluence with the Colorado River	From the Town of Fraser to the confluence with the Colorado River.	Cu			
COUCUC12	Lakes and Reservoirs within Arapahoe National Recreation Area including Grand Lake, Shadow Mountain Lake and Lake Granby	Shadow Mountain Lake		D.O.	H	
COUCUC12	Lakes and Reservoirs within Arapahoe National Recreation Area including Grand Lake, Shadow Mountain Lake and Lake Granby	Lake Granby		Aquatic Life Use (Hg FCA)	H	
COUCYA02a	Mainstem of the Yampa River from Wheeler Creek to Oak Creek.	Yampa River below Stagecoach Reservoir	Mn, Se			
COUCYA02b	All lakes and reservoir tributary to the Yampa River, Elkhead Creek, and the Little Snake River.	Elkhead Reservoir, Lake Catamount		Aquatic Life Use (Hg FCA)	H	
COUCYA02b	All lakes and reservoir tributary to the Yampa River, Elkhead Creek, and the Little Snake River.	Stagecoach Reservoir	D.O. 			
COUCYA02c	Yampa River, from Oak Creek to Elkhead Creek	all	temperature			
COUCYA03	All tributaries to Yampa River except for specific listings, on USFS land	Bushy Creek		Sediment	L	
COUCYA03	All tributaries to Yampa River except for specific listings, on USFS land	Walton Creek	Mn			
COUCYA03	All tributaries to Yampa River except for specific listings, on USFS land	Little Morrison Creek	Zn, Fe(dis)			
COUCYA04	Little White Snake Creek, source to Yampa River	all	D.O.			
COUCYA08	Elk River including tributaries and wetlands from the source to Yampa River	Elk River below Morin Ditch		E. coli	H	
COUCYA08	Elk River including tributaries and wetlands from the source to Yampa River	Lost Dog Creek	Hg			
COUCYA13b	Foidel Creek and tributaries, Fish Creek, Middle Creek and tributaries	Fish Creek	E. coli			
COUCYA13d	Dry Creek including all tributaries and wetlands from source to the Yampa River	Below Seneca sample location 8 (WSD5)		Se	L	
COUCYA13d	Dry Creek including all tributaries and wetlands from source to the Yampa River	all		Fe(Trec)   	L	
COUCYA13d	Dry Creek including all tributaries and wetlands from the source to the Yampa River	Dry Creek below Routt County Road 53 (Sec. 22, T6N, R88W)	Pb, E. coli			
COUCYA13e	Sage Creek, Grassy Creek and tribs	Sage Creek below Routt County Road 51D		Se	L	
COUCYA18	Little Snake River including all tributaries and wetlands from forest boundary to Wyoming border	all	Cu			
93.4 - 93.9  Reserved
93.10	STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; MARCH, 2004 RULEMAKING
The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; 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 (303(d) List)
A.	Introduction
This regulation establishes Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”).  This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.
Once listed, the State is required to prioritize these water bodies or segments (rivers, streams, lakes reservoirs) based on the severity of pollution and other factors.  It will then determine the causes of the water quality problem and allocate the responsibility for controlling the pollution.  This analysis is called the TMDL Process, and results in the determination of: 1) the amount of a specific pollutant that a segment can receive without exceeding a water quality standard (the TMDL), and 2) the apportionment to the different contributing sources of the pollutant loading (the allocation).  The TMDL must include a margin of safety, waste load allocation (for point sources) and a load allocation (for non-point sources and natural background).  The TMDL must include upstream loads in the assessment and apportionment process.
B.	List Development
1.	Listing Methodology
The “Section 303(d) Listing Methodology - 2004 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority.  The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on September 9, 2003.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2004 Section 303(d) List and the 2004 M&E List.  However, this methodology was not adopted by the Commission as a rule.  The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
2.	Information Considered
The Commission has considered all existing and readily available information in developing the 2004 Section 303(d) List.  In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii).  In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party.  The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations.  Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as "readily available" for purposes of making the 2004 listing decisions.  Such information will be considered in the next listing cycle.
C.	Prioritization
The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources.  Priorities of High, Medium and Low were established according to section IV. of the 2004 Section 303(d) Listing Methodology.  Segments/parameters where the Commission determined that an appropriate plan is in place to resolve the uncertainty as specified in section 93.4 have been denoted as “L*”.  A Low priority may also be assigned to other segments as per section IV.
D.	Discussion of Issues Raised in the Hearing
During the course of the hearing, the status of approximately 30 segments was debated.  The basis for the Commission’s decisions regarding the major issues for these segments is recorded below.
1.	Selenium:  Several parties questioned whether selenium, where the source is underlying native shale, should be considered a pollutant.  The Commission found that selenium, like many other naturally occurring metals in Colorado is a pollutant and is classified as such on EPA’s list of priority toxic pollutants (62 FR 42160).  If the source of impairment is natural, that is grounds for consideration of an ambient quality-based, site-specific standard as described in Regulation No. 31 at 31.7 1(b)(ii).  However, the listing decisions must be made based upon a comparison of the current adopted standard and the ambient condition for the segment.  Although parties to the rulemaking submitted testimony questioning the decision to list several specific segments for selenium, such as Lower Colorado River segment 3 and Lower Arkansas River segment 1a, the evidence provided was directed largely at questioning the appropriateness of the current selenium standards.  The Commission has determined, based on the evidence submitted, that these segments are not in attainment of the current selenium standards.
2.	Segments where there is no new data, but following the 2004 Listing Methodology resulted in a different conclusion than in 2002:  The following segments had no new data included in the assessments since the 2002 listing cycle.  However, clarification and changes in the 2004 Listing Methodology resulted in the segments moving from the Monitoring and Evaluation List to the 303(d) List.  The modifications that resulted in the most changes had to do with more clearly specifying that segments with small datasets where the ambient condition exceeds the standard by more than 50 percent should be listed.  The following segments were affected:
Gunnison River Basin:		Lower Gunnison segment 27
				Uncompahgre segment 2
Lower Colorado River Basin:	White River segment 9b
3.	Segments with multiple tributaries:  Issues were raised regarding what is the appropriate way to handle segments with multiple tributaries where there is evidence of impairment.  The Commission found that since segments are generally treated as having consistent uses and characteristics, their impairment should be handled in a similar fashion.  Unless either water quality data or other evidence has been presented that shows that the impairment is not present in the entire segment, the entire segment has been listed as impaired.  “Other evidence” may include changes in geology within a segment or the confluence with a stream known to be impaired.  Nevertheless, it is anticipated that before any TMDL is developed and implemented in “all tributary” segments, work will be performed to determine the causes and locations of the impairment, such that efforts and controls are not inappropriately directed towards individual tributaries that are not truly of concern, and the Section 303(d) List can be modified accordingly.  Where other evidence shows that some portions are in exceedance and other portions are not, only the impaired portion needs to be listed.  The following segments were listed based on this rationale:
Gunnison River Basin:		Lower Gunnison segments 4a and 4b
				North Fork segments 5 and 6
Lower Colorado River Basin:	Lower Colorado segment 4a
E.	Segment- Specific Issues
1.	San Juan Basin, Dolores River below McPhee Reservoir:  Despite a recent decline in the fish population in this reach, the Commission found that there was not adequate readily available evidence to conclude that there exists an impairment of the aquatic life use due to other than extraordinary events associated with the long-term drought that has existed in southwest Colorado for several years.  In view of evolving operations of McPhee Reservoir and varying (and generally declining) hydrologic conditions, the Commission is not able at this time to identify an “expected condition” upon which to base a decision of impairment.  Further, even if an impairment caused by other than the extraordinary events associated with the drought were found to exist, the Commission could not conclude based on this record that the decline was due to a “pollutant” as compared to “pollution.”  Nevertheless, the Commission encourages cooperation by all interested parties in the implementation of habitat improvement measures that may serve to enhance the quality of the fishery in the reach.  The Commission is prepared to revisit the concept of “expected condition” as it applies to this reach should that be warranted by changes in habitat condition.  Certainly the achievement of goals set under the 1996 Operating Agreement for McPhee Reservoir may influence the nature of the expected condition.  Finally, any evidence of impairment due to pollutants can be brought forth at the next listing hearing.
2.	South Platte Basin, Clear Creek, segments 14b and 15:  Available data, with specific reference to biological information on fish species collected over time and visual observations of the physical condition of the stream bed, provide an indication of “use-impairment” for Clear Creek Segments 14b and 15 relative to aquatic life.  Though organic sediment appears to be a significant contributor to the impairment, the exact interaction of potentially numerous causative factors need to be further explored.  No single source or cause of the impairment has been identified to date.  Coors Brewing Company has voluntarily come forward with a study plan for segments 14a, 14b and 15 as part of the “pilot study” approach outlined in the section 309 study report recently submitted to the State Legislature.  This pilot study would assist in defining the expected condition for these segments in view of existing hydrological/habitat conditions and in fashioning the best approach to remedying the impairment.  Should Coors decide to proceed with the pilot study, the Division will identify segments 14b and 15 as “low priority” and refrain from any further TMDL implementation measures until such time as the study results are known and an appropriate approach to rectifying the identified problems is crafted in cooperation with basin stakeholders.
3.	Upper Colorado Basin, Blue River segments 6 and 8 (Camp Cr, Jones Gulch, Keystone Cr, and Mozart Creek):  The four identified tributaries in these two segments were proposed by the Division to be listed as impaired relative to measured pH levels.  The evidence submitted raised questions regarding the representativeness of the data showing a possible standards exceedance, particularly in the absence of data regarding seasonality of pH levels for multiple years.  Therefore, the Commission determined that it is more appropriate to include these specific tributaries on the Monitoring and Evaluation List at this time.  Keystone Resorts has stated that it will complete a Use Attainability Analysis for Camp Creek and Jones Gulch, and that it is willing to include Keystone Creek and Mozart Creek in this analysis.  The Commission believes that it is appropriate to revisit the attainment status of these segments following completion of the UAA.  Depending on the results of this analysis, the adoption of site-specific seasonal pH standards is one option that can be considered.  Indeed, the Commission notes that the evidence submitted to it showed that nearby snowmaking actually mitigates pH levels in the snow.
4.	Uncompahgre River, segment 6b (Red Mountain Creek):  The Commission does not believe that an impairment of the aquatic life use of segment 6b relative to a realistic expected condition for this segment has been shown.  The Commission found that the aquatic community in segment 6a is not the appropriate expected condition for this segment.  The Commission endorses the Division’s proposal not to list at this time, while moving forward to investigate segment 6b and make a recommendation to the Commission regarding the attainable aquatic life use and appropriate numeric standards in the context of the next basin-wide standards and classification rulemaking proceedings.  However, it is uncertain at this time whether any future remediation activities in this area will improve the aquatic life use of this segment.  In the absence of documentation that the attainable expected condition for this segment is an aquatic life use that is better than the current condition of this segment, it would be inappropriate to identify this segment as impaired.
5.	Bear Creek segment 1a: This segment was proposed by the Division and by Trout Unlimited to be included on the Section 303(d) List.  The evidence submitted demonstrated adverse impacts to the aquatic life use in this segment during 2002, and documented that the use had started to recover in 2003, although full recovery had not yet occurred.  The evidence also demonstrated that the unusual and extreme drought conditions in 2002 were the determinative cause of the adverse impacts to aquatic life.  Although there was evidence submitted indicating that ammonia concentrations or elevated temperatures may have adversely affected the aquatic life, the evidence demonstrated that these potentially harmful conditions would not have been present except for the drought.  The Commission has concluded that this segment should be included on the Monitoring and Evaluation List for potential aquatic life, ammonia and temperature impairments, and that its status should be reconsidered in future updates of Regulations No. 93 and No. 94.  Any evidence of impairment due to pollutants can be brought forth at the next listing hearing.
6.	Lower Colorado segment 13b:  This is an “all tributaries” segment that was proposed by the Division to be listed in its entirety for selenium.  All of the ambient water quality data available in the record for this hearing was from tributaries on the north side of the Colorado River.  In addition, there was testimony regarding significant differences in the geology on the north and south sides of the Colorado River in this area.  Therefore, the Commission determined that it is appropriate that only the tributaries on the north side of this segment should be listed as impaired for selenium.
7.	West Fork of Clear Creek, segment 5:  The Commission found that the acute zinc standard in the West Fork of Clear Creek was exceeded more than once in three years.  Because the chronic zinc standard is in attainment, and because Climax presented credible biological evidence that the aquatic life use classification is supported, the Commission determined that listing for acute zinc is not warranted in this instance.  This segment is included on the Section 303(d) List as impaired for copper.
8.	Middle South Platte segment 1:  The Division proposed that the portion of this segment from Big Dry Creek to Highway 60 be included on the Section 303(d) List as impaired for dissolved oxygen during the months of August and September.  The evidence submitted offered conflicting interpretations of what the available data for this segment show regarding attainment.  Because this segment appears to be in compliance with dissolved oxygen standards based on the established convention of looking at the 15th percentile of the available data for the entire segment, the Commission determined that it is more appropriate at this time to include this segment on the Monitoring and Evaluation List for further assessment of dissolved oxygen conditions.  The Commission also believes that future clarification of the appropriate methodology for assessing attainment of dissolved oxygen standards, e.g. within specific months of the year, would be helpful.
F.	Plans to Resolve Uncertainty
Three parties presented plans to resolve uncertainty for segments that have temporary modifications based on uncertainty [see Regulation No.  31.7(3)(a)(iii)].  These segments will not be subject to the development of a TMDL as long as there is a plan in place that addresses the following:
(1)	There is an appropriate plan in place to remove the uncertainty;
(2)	The plan includes an implementation schedule that will resolve the uncertainty in a time frame consistent with Colorado’s timeline for the development of TMDLs; and
(3)	The plan is being implemented in accordance with its terms.
The Commission found that the following segments have adequate plans.  It is the Commission’s intent to revisit these plans at the next listing cycle to determine if they continue to meet the Commission’s intent.
1.	Fountain Creek segment 6 (Monument Creek from the National Forest boundary to Fountain Creek):  The selenium water quality standard for Fountain Creek segment 6 has a temporary modification for uncertainty pursuant to section 31.7(3)(a)(iii) of the Basic Standards.  The City of Colorado Springs submitted an appropriate plan to remove the uncertainty 
2.	Lower Arkansas segment 1a (Arkansas River from Fountain Creek to the Colorado Canal):  The selenium water quality standard for Lower Arkansas segment 1a has a temporary modification for uncertainty pursuant to section 31.7(3)(a)(iii) of the Basic Standards.  The City of Pueblo submitted an appropriate plan to remove the uncertainty 
3.	Upper Yampa segment 13d (Dry Creek):  In the 2003 Upper Colorado River rulemaking hearing, the Commission adopted a temporary modification (based on uncertainty) of 60 ug/L for selenium in Dry Creek.  This temporary modification was based on five WQCD samples collected in Dry Creek in 2001 and 2002 near its confluence with the Yampa River.  The Commission approved Seneca Coal Company’s plan to monitor Dry Creek with the objective of determining the source or sources of selenium loading, where the loading is isolated in the lower portion of Dry Creek and to determine whether the loading is due to natural or irreversible man-induced sources.
BASIS AND PURPOSE (Monitoring and Evaluation List)
A.	Introduction
This regulation establishes Colorado’s Monitoring and Evaluation List.  This list was prepared as part of the effort to identify water bodies for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards (those impaired waters requiring TMDLs).  Regulation No. 93 is the list of impaired waters which require TMDLs.  This regulation is the Monitoring and Evaluation List  (“M&E List”) that identifies water bodies where there is reason to suspect water quality problems, but there is also uncertainty regarding one or more listing factors, such as the representative nature of the available data.  Water bodies that are impaired but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution are also included on the M&E List.  
B.	List Development
The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed. 
C.	Prioritization and Scheduling
The Division has committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle.  Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.
D.	Segment-Specific Issues
1.	Blue River segment 3:  The Commission has included Gold Run Gulch below Jessie Mine (for cadmium and zinc) and the South Branch Swan River below Royal Tiger Mine (for zinc) on the Monitoring and Evaluation List.  The Royal Tiger Mine and the Jessie Mine are both part of a CERCLA remediation effort, for which remedial project design is currently out to bid.  Therefore, the Commission understands that the conditions in this area affecting water quality will be changing and that it is currently uncertain what uses or water quality can be supported in these waters in the future.  The Commission does not intend by including these waters on the Monitoring and Evaluation List to conclude that any actions other than those CERCLA-related activities already underway are necessary or appropriate at this site.  The status of those efforts will be reviewed during the next update of this list.
2.	Segments proposed for the Section 303(d) List:  In several specific instances, the Commission made a determination in this rulemaking hearing that segments proposed by the Division or others for inclusion on the Section 303(d) List should instead be included on the Monitoring and Evaluation List.  This applies in particular to Bear Creek segment 1a and Middle South Platte segment 1 in the South Platte Basin and to four named tributaries in Blue River segments 6 and 8 in the Upper Colorado River Basin.  In each of these instances, the rationale for the Commission’s decision to included these waters on the Monitoring and Evaluation List is set forth in the Statement of Basis and Purpose adopted for Regulation No. 93 as a result of this rulemaking.
93.11	STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; FEBRUARY, 2006 RULEMAKING, EFFECTIVE DATE OF APRIL 30, 2006
The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; 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 (303(d) List)
A.	Introduction
This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) to reflect additional water quality information available since the Regulation was promulgated in 2004.  This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.
B.	List Development
1.	Listing Methodology
The “Section 303(d) Listing Methodology - 2006 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority.  The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 9, 2005.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2006 Section 303(d) List and the 2006 M&E List.  However, this methodology was not adopted by the Commission as a rule.  The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
2.	Information Considered
The Commission has considered all existing and readily available information in developing the 2006 Section 303(d) List.  In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii).  In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party.  The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations.  Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as "readily available" for purposes of making the 2006 listing decisions.  If submitted, such information will be considered in the next listing cycle.
C.	Prioritization
The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources.  Priorities of High, Medium and Low were established according to section IV. of the 2006 Section 303(d) Listing Methodology.  
D.	Temporary Modifications and Plans to Eliminate Uncertainty
Consistent with the recent changes to the Basic Standards and Methodologies for Surface Water (Regulation No. 31) and the Discharge Permit Regulations (Regulation No. 61), the Commission deleted subsection 93.4 “Plans to Eliminate Uncertainty.”  The Statement of Basis for the June 2005 rulemaking hearing for Regulation No. 31 states:
The Commission recognizes that portions of the temporary modification provisions adopted in this rulemaking may be inconsistent with current provisions in Regulation No. 93.  The Commission intends that the provisions adopted in this rulemaking will govern until appropriate revisions will be adopted in the Regulation No. 93 in the next rulemaking hearing reviewing that regulation.
In 2004, this provision was added to Regulation No. 93 to identify those waterbodies where work independent of the TMDL process was proceeding to identify the appropriate underlying standards.  In these cases, TMDLs and permit limits were not to be based on the underlying standards until the uncertainty was resolved.  The intent was that dischargers should not be forced to comply with underlying standards where there is ongoing work being done to resolve acknowledged uncertainty regarding the appropriateness of those underlying standards.  
Dischargers are now protected from complying with underlying standards before the uncertainty is resolved by recent changes in the Basic Standards and the Permit Regulations.  Now, for discharges to waters where a temporary modification has been adopted, a permit may contain compliance schedules that recognize this ongoing work and may extend beyond the end of the permit term.  The Commission believes it appropriate for dischargers to focus their available resources on addressing uncertainty with respect to appropriate water quality standards, rather than on complying with standards that may change in a short time.
Consistent with this new approach to temporary modifications, the Commission intends that a more thorough consideration will be given to the causes and sources of non-attainment before temporary modifications are proposed.  In cases where the appropriate way to address non-attainment of underlying standards is through the TMDL program, not through adoption of temporary modifications, the Commission may assign a higher TMDL priority to such waters.
E.	Segment- Specific Issues
Fountain Creek segment 2a:  The Division had proposed inclusion of this segment due to non-attainment of the assigned E. coli standard.  The Division noted that its proposal erroneously identified the listing as a “low” priority.  The Section 303(d) Listing Methodology, 2006 Listing Cycle indicates that TMDLs for waters in non-support of Recreation 1a use classifications be designated as “high” priority.  The Commission has therefore adopted a “high” priority designation for this segment.
Fountain Creek segment 2b:  This segment is the lowermost of three that comprise the mainstem of Fountain Creek.  Both of the upper two segments are included on the List of Impaired Waters for E. coli.  The Sierra Club had proposed that this lowermost segment should also be listed for E. coli.  The Commission has decided that the Division’s analysis of the available data is consistent with the procedures contained in the Section 303(d) Listing Methodology, 2006 Listing Cycle and that the results of that analysis do not support inclusion of this segment on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs.
North Fork Gunnison River segment 6:  The Division had proposed that this “all tributary” segment be listed in its entirety for non-attainment of the aquatic life use-based chronic selenium standard.  The Colorado River Water Conservation District provided evidence that the standard is, in fact, attained at several locations within this segment.  It is therefore appropriate that only that portion of the segment for which non-attainment has been documented be included on the list.  The Commission has identified the affected portion of the segment as “Cottonwood Creek” and has revised the proposal accordingly.  
Uncompahgre River segment 6b (Red Mountain Creek):  The Commission had in a February 2004 Rulemaking Hearing determined that there is not adequate data to support a finding of impaired Aquatic Life Use relative to the expected condition.  Information offered in the 2006 hearing further reinforces this conclusion by demonstrating that the Commission’s classification assumes an extremely limited aquatic life use in this segment.  In a rulemaking hearing scheduled for June 12, 2006, the Commission will consider a proposal to delete the aquatic life use classification for this segment.  The Commission has therefore opted not to include Red Mountain Creek on the 2006 Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs.
Lower Gunnison segment 2:  The Division proposed that this segment be listed for selenium and temperature, with a "high" priority for each.  In view of evidence that it may be appropriate to reconsider the cold water aquatic life classification of this segment prior to initiating a TMDL, the Commission chose to change the priority for the temperature listing to "low".
Lower Colorado River segment 3:  The Division had initially proposed listing of this segment for ammonia.  During discussions with the City of Grand Junction it was noted that during the course of the Division’s assessment an error had been made relative to the dataset utilized.  The Division subsequently modified its proposal to withdraw this segment from its proposal.  The Commission has not included the segment on the 2006 Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs.
Lower Colorado River segment 13a (Salt Creek):  Salt Creek was proposed by the Division to be listed for sediment based upon a study of this and other tributary segments performed in conjunction with the BLM and Chadwick and Associates.  Mesa County objected to the inclusion of Salt Creek on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs, arguing that the assessment protocols used were inconsistent with Commission Policy 98-1, the Implementation Guidance for Determining Sediment Deposition Impacts to Aquatic Life in Streams and Rivers.  The assessment performed utilized the same approach embodied in the Sediment Guidance with respect to comparison of the affected reach to an expected condition.  The validity of this comparative, expected condition analysis is not dependent on this being a high gradient, cobble bottom stream.   The Commission has determined that the assessment adequately demonstrated non-attainment of the narrative sediment standard and consequent impairment of Salt Creek.   
Bear Creek segment 1a:  The Division proposed that this segment be retained on the Monitoring and Evaluation list for non-attainment of the assigned aquatic life use classification and for temperature.  The evidence submitted demonstrated adverse impacts to trout populations at two stations (Bear Creek cabins and O’Fallon Park) situated in the upper reach of this segment since 2002 and documented that the use continued to recover well into 2004, although full recovery had not yet occurred.  This evidence is consistent with the Commission’s conclusion in 2004 that the demonstrative cause of adverse impacts to aquatic life was the extreme drought in 2002.  The 2006 Listing Methodology states that “Data collected during or immediately after temporary events influencing the waterbody that are not representative of normal conditions shall typically be discounted in making the listing decision.”  Several parties argued that water quality conditions might have adversely affected the aquatic life.  However, there was no evidence submitted demonstrating exceedance of the Mean Average Weekly Temperature criterion during 2004 or 2005, or demonstrating that impairment was otherwise caused by pollutants.  The Commission has decided that the Division’s interpretation of the available data is consistent with the procedures contained in the Section 303(d) Listing Methodology, 2006 Listing Cycle and has determined that this segment should be retained on the Monitoring and Evaluation List for aquatic life impairments and temperature, and that its status should be reconsidered in future updates of Regulations No. 93 and No. 94.
The fact that impacts to Bear Creek aquatic life continue to appear to be related to the 2002 extreme drought is an adequate and appropriate basis for including this segment on the Monitoring and Evaluation List, rather than the Section 303(d) List.  However, the Commission also notes that, even if continuing impacts did not appear to be tied to the drought, where there is no evidence that a numerical standard has been exceeded, the Commission’s practice has been to place waters on the Monitoring and Evaluation List if there is not evidence that a use impairment has been caused by a pollutant.  The 2006 Listing Methodology states “Water bodies that are impaired but it is unclear whether the cause of impairment is attributable to pollutants as opposed to pollution will be placed on the M&E List.”  EPA’s guidance for such circumstances differs.  EPA’s guidance says that where there is an impairment but there has not been a demonstration that the impact is not caused by a pollutant, the water segment should be included on the Section 303(d) List.  Because this provision appears in EPA guidance only, and the Commission is aware of no specific provisions of the Clean Water Act or EPA regulations that would dictate this result, the Commission believes that it has policy discretion to use different approach – i.e., to refrain from listing unless a pollutant has been identified as the cause of the use impairment.
Clear Creek segment 13b (North Fork Clear Creek):  The Division had proposed this segment be retained on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs for several parameters and for non-attainment of the assigned aquatic life use classification.  The Commission has adopted this proposal, but notes that the segment attains the assigned numeric copper standard.  The listing therefore does not include copper.  Further, the Commission notes that the Division had proposed a “high” priority for completion of TMDLs for this segment, due to the fact that the North Fork of Clear Creek was included on the 1998 List of Impaired Waters and is therefore subject to provisions of the 1999 Settlement Agreement addressing TMDL development by the Division.  The Commission has determined that a “medium” priority will be assigned for TMDL development, while recognizing that the Division remains obligated to completion of TMDLs for this segment by June 30, 2008.  If the underlying standards are revised in the 2009 South Platte River basin rulemaking, TMDLs and/or Wasteload Allocations based on the superceded standards should be revisited.
Cache la Poudre segment 14 (Horsetooth Reservoir):  The Division proposed inclusion of Horsetooth Reservoir on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs due to non-attainment of the dissolved oxygen standard.  Data for a ten-year period of record was found to be representative of conditions in the Reservoir.  The Commission determined that in this instance it is appropriate to consider data for more than the most recent five years, in view of evidence that the most recent five years include a potentially unrepresentative period of reservoir drawdown.  While the available data do not include samples spaced throughout a 24-hour period, the data are typical of that usually available for lakes and reservoirs.  If diel variation were expected, it is likely that any such data would demonstrate a slight depression of dissolved oxygen concentration in the epilimnion during non-daylight hours.  However, the area of non-attainment of dissolved oxygen in Horsetooth Reservoir is in the metalimnion, or middle layer of the reservoir.  Testimony from Division staff indicated that it is unlikely that diel variation in dissolved oxygen levels would be expected in the metalimnion, since this deeper layer is unlikely to be affected by photosynthesis that occurs in the epiliminion.  The Commission interprets the reference in the Listing Methodology to lake and reservoir samples representative of diel variation to apply only in those factual circumstances (e.g. dissolved oxygen in the epilimnion) where such variation would be expected.  
The assessments and recommendations by the Division regarding Horsetooth Reservoir were consistent with the Section 303(d) Listing Methodology, 2006 Listing Cycle.  However, the Commission notes that this hearing identified a need to provide further clarifications regarding appropriate procedures for assessing compliance with dissolved oxygen standards, particularly for lakes and reservoirs.  The Commission encourages the Division to pursue such clarifications in preparation of the 2008 Listing Methodology, including, e.g., addressing variations in attainment status from year-to-year and further clarification of what constitutes representative data.  
Evidence regarding the status of aquatic life in Horsetooth Reservoir does not override the fact that the data demonstrate a long term standards exceedance.  The Commission’s practice has been to list waterbodies on the Section 303(d) List whenever representative data demonstrate non-attainment of a numerical standard, including dissolved oxygen.  For other waters listed for non-attainment of dissolved oxygen, the Commission has not required evidence of the cause of the non-attainment.  Although the provisions of the 2006 Listing Methodology arguably contain potentially conflicting language on this point, the Commission’s practice has not been to apply the provision regarding “water bodies that are impaired but it is unclear whether the cause of impairment is attributable to pollutants” to waters with dissolved oxygen impairments.  Moreover, although the Commission was willing to consider listing Horsetooth Reservoir on the M&E List if the cause of the dissolved oxygen impairment was recent reservoir draw downs (i.e., reservoir operations), the evidence did not support this conclusion.
Middle South Platte River segment 03a (Horse Creek Reservoir):  The Division proposed that Horse Creek Reservoir be included on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs due to non-attainment of the assigned pH standard.  The recommendation was based upon a representative dataset including four years of water quality monitoring results.  The Commission has determined that inclusion of the Reservoir on the Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs for pH is appropriate and consistent with the Section 303(d) Listing Methodology, 2006 Listing Cycle.  Dissolved oxygen data for the same four-year period demonstrate attainment of the dissolved oxygen standard.  Although EPA questioned the Division’s current practice of averaging dissolved oxygen data within the sampling profile or profiles for a single sampling event, the Commission has determined that this practice is acceptable and appropriate, and consistent with the 2006 Listing Methodology.  EPA’s proposal that Horse Creek Reservoir be listed for dissolved oxygen is based upon analytical procedures that are inconsistent with the Division’s current assessment practice.  The Commission has determined that the Reservoir is not impaired with respect to the dissolved oxygen standard. 
Upper Colorado River segment 07b (Muddy Creek):  The Division had proposed the listing of Muddy Creek for non-attainment of the assigned temperature standard.  The Colorado River Water Conservation District objected to the Division’s proposal and has provided evidence suggesting that the USGS sampling station (data from which formed the basis for the Division’s proposal) is situated such that any temperature data generated is likely not representative.  The Commission has therefore included the segment on the 2006 Monitoring and Evaluation List to allow further examination of temperature data from this station.
Upper Yampa River segment 07b:  This segment comprises a portion of the Yampa River mainstem.  The Division had proposed that this segment be listed for temperature, again based upon USGS monitoring data.  The Colorado River Water Conservation District provided evidence concerning the location of the USGS sampling station below the Steamboat Springs hot springs discharge.  Again parties have agreed that such data is likely not representative of instream conditions.  The Commission has placed the segment on the 2006 Monitoring and Evaluation List.
Upper Yampa River segment 20 (First Creek, Elkhead Creek):  These waters are classified for Recreation Use 1a, and are assigned a numeric E coli standard of 126 org./100 mL.  Ambient E. coli levels exceed the assigned numeric standard.  The U. S. Forest Service has raised concerns regarding the current assigned Recreation Use and the associated numeric standards.  The Commission has included the segment on the 2006 Section 303(d) List of Water-Quality-Limited Segments Requiring TMDLs based upon the current classification and standards.  However, it is the intent of the Commission that these issues be examined in the context of the 2008 Upper Colorado surface water standards rulemaking prior to the initiation of the TMDL development process.
BASIS AND PURPOSE (Monitoring and Evaluation List)
A.	Introduction
This regulation updates Colorado’s Monitoring and Evaluation List to reflect additional water quality information available since the Regulation was promulgated in 2004.  
B.	List Development
The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed. 
C.	Prioritization and Scheduling
The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle.  Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.
D.	Segment-Specific Issues
In a number of instances, the Commission chose in this hearing to include on the Monitoring and Evaluation List waters that were initially proposed by the Division, or recommended by other rulemaking participants, for inclusion on the Section 303(d) List, Regulation #93.  These waters include Bear Creek segment 1a, Upper Colorado River segment 07b (Muddy Creek), and Upper Yampa River segment 07b.  In each instance, the Commission’s rationale for these decisions is set forth in the statement of basis and purpose for Regulation #93.
PARTIES TO THE RULEMAKING
1.	The City of Grand Junction
2.	The Colorado Division of Wildlife
3.	Evergreen Trout Unlimited and Colorado Trout Unlimited
4.	The City of Colorado Springs
5.	The City of Black Hawk
6.	The Colorado River Water Conservation District
7.	Friends of Bear Creek
8.	Big Thompson Watershed Forum
9.	The Bear Creek Watershed Association
10.	The Northern Colorado Water Conservancy District
11.	U.S. Environmental Protection Agency, Region 8
12.	Evergreen Metropolitan District and West Jefferson County Metropolitan District
13.	USDA Forest Service, Medicine Bow-Routt National Forests
14.	Colorado Rock Products Association
15.	City and County of Broomfield
16.	Climax Molybdenum Company
17.	The Metro Wastewater Reclamation District
18.	Mount Carbon Metropolitan District
93.12	STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; FEBRUARY, 2008 RULEMAKING, EFFECTIVE DATE OF APRIL 30, 2008
The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; 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 (303(d) List)
A.	Introduction
This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) to reflect additional water quality information available since the Regulation was promulgated in 2006.  This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.
B.	List Development
1.	Listing Methodology
The “Section 303(d) Listing Methodology - 2008 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority.  The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 15, 2007.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2008 Section 303(d) List and the 2008 M&E List.  However, this methodology was not adopted by the Commission as a rule.  The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
2.	Information Considered
The Commission has considered all existing and readily available information in developing the 2008 Section 303(d) List.  In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii).  In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party.  The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations.  Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as "readily available" for purposes of making the 2008 listing decisions.  Such information will be considered in the next listing cycle.
C.	Prioritization
The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources.  Priorities of High, Medium and Low were established according to section IV. of the 2008 Section 303(d) Listing Methodology.  
D.	Fish Consumption Advisory Listings
Consistent with the 2008 Section 303(d) Listing Methodology, the Division proposed to include 12 segments on the 2008 303(d) List for non-attainment of the aquatic life use due to fish consumption advisories for mercury.  The 2008 Section 303(d) Listing Methodology, states:
Fish Consumption Advisories are issued by the Colorado Department of Public Health and Environment (“CDPHE”) in instances where analysis of fish tissue samples provides documentation of a public health risk.  Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified.  
The 2006 303(d) List included three of these reservoirs for impairment due to mercury:  one in the Rio Grande basin: Sanchez Reservoir (Rio Grande, segment 30), and two in the San Juan basin:  McPhee Reservoir (Dolores, segment 4) and Narraguinnep Reservoir (La Plata, segment 11).  These listing were changed by the Commission to specify that the listing was based on non-attainment of the aquatic life.  This is consistent with the 2008 Listing Methodology and avoids confusion that there is non-attainment of the mercury standard in the water column.
The Commission has included 12 segments on the 2008 303(d) List for non-attainment of the aquatic life use due to mercury fish consumption advisories for 13 lakes or reservoirs.  The Commission also included one listing based on non-attainment of the aquatic life use due to a PCE fish consumption advisory in Willow Springs Ponds, Fountain Creek, segment 7a.
E.	Discussion of Issues Raised in the Hearing
Dissolved Oxygen Standard in Lakes and Reservoirs: The issue of an appropriate D.O. standard in lakes and reservoirs was raised in this hearing by two parties, Northern and the River District.  The River District focused its attention to high elevation lakes and reservoirs while Northern discussed the concept of representative data and assessment methods as outlined in the 2008 Listing Methodology.  The Division agreed that work is needed to examine the D.O. standard for lakes and reservoirs and that additional refinement of the Listing Methodology is appropriate including consideration of whether and how refugia should be addressed.  This standard is scheduled for review in preparation for the 2010 Basic Standards and Methodology, Regulation No. 31, RMH in June 2010.  The Commission directs the Division to work with parties in 2008 and 2009 on any changes that are deemed appropriate for the 2010 Listing Methodology.  The Commission made listing decisions based on the available data using the adopted standards and the 2008 Listing Methodology.  Site-specific decisions made by the Commission are discussed below.
F.	Segment- Specific Issues
Fountain Creek segment 6, Monument Creek: Mainstem of Monument Creek from the boundary of National Forest Lands to the confluence with Fountain Creek:  The Division had proposed retaining the portion of Monument Creek below Mesa Road on the 2008 303(d) List because selenium concentrations in that portion exceed the water quality standard for Fountain Creek Segment 6.  The Commission has determined that it is appropriate at this time to include this portion of Monument Creek on the 2008 303(d) List.  However, because there is an appropriate plan in place to address the segment as a whole, the Commission directs the Division and Colorado Springs Utilities to revisit this plan to determine the causes and potential reversal of elevated Se concentrations and the appropriate long-term underlying standard for this section of COARFO06.
Lower Colorado segment 2, Colorado River (COLCLC02):  Mainstem of the Colorado River from Parachute Creek to the Gunnison River.  The Division originally proposed listing this segment based on non-attainment of the selenium standard.  The Division based its proposal on data from multiple sampling locations.  The River District questioned whether some of the sample locations, including the Humphrey backwater location and others, were in the segment.  The Division reviewed the sampling locations and determined that some of the sampling locations used in the original proposal were outside the segment.  The segment was reassessed and still showed impairment.  The parties disagree whether Humphrey Backwater is located within the segment but agreed that it demonstrated exceedences of the selenium standard.  The Commission ultimately decided to list the Humphrey Backwater portion of the Colorado River segment based on those data, rather than listing the entire segment.
White River segment 13b:  Shell Frontier Oil and Gas Inc. provided additional analytical results for a number of locations within the Yellow Creek drainage.  Re-assessment of several waters which had been proposed for inclusion on the Monitoring and Evaluation List indicated that Corral Creek, Box Elder Gulch, Stake Springs and Duck Creek, are all in attainment of the assigned standard for total recoverable iron.  This additional data, however, also demonstrated that the lower portion of Corral Creek and Duck Creek are in non-attainment of the Aquatic Life Use-based chronic selenium standard.  The Commission has added these waters to the 303(d) List for selenium. 
Upper Colorado segment 5, Wolford Mountain Reservoir (COUCUC05):  The River District opposed the Division’s proposal to move Wolford Reservoir from the 2006 M&E List to the 2008 303(d) List when no additional data has been collected.  In addition, the River District expressed their concerns with the current D.O. standard and Listing Methodology especially as it is applied to high alpine lakes and reservoirs.  The Commission moved Wolford Reservoir from the M&E List to the 303(d) List based on the current standards and listing methods.  The Commission has encouraged the Division, the River District and other parties to continue to work towards an improved D.O. standard for the 2010 Basic Standards Rulemaking Hearing. The Commission adopted a low priority for this listing, since it is appropriate for the D.O. standard and listing methodology issues to be addressed before substantial resources are expended on development of a TMDL. 
Uncompahgre segment 14, Sweitzer Lake (COGUUN14): The Division proposed listing for Sweitzer Lake due to exceedances of the D.O. standard in the mixed layer.  The River District pointed out that there was no thermal stratification and adequate refugia present and therefore the segment should not be listed.  They also indicated that there is evidence of chemical stratification. The Commission listed Sweitzer Lake, segment COGUUN14, on the 303(d) List due to exceedances in the mixed layer as defined in the Listing Methodology.
Upper Yampa segment 13d, Dry Creek (COUCYA13d):  The Division proposed listing the Hubberson Gulch tributary of this segment due to non-attainment of the total recoverable iron standard.  Seneca Coal Company (Seneca) provided evidence that the tributary is in attainment of the standard.  The Commission did not list the segment for total recoverable iron on the 303(d) List. 
Upper Yampa segment 13e, Sage and Grassy Creeks (COUCYA13e):  The Division proposed listing this segment due to non-attainment of the total recoverable iron and dissolved selenium standards.  Seneca provided evidence that the total recoverable iron standard is attained within the segment.  The Commission did not include the segment on the 303(d) List for total recoverable iron.  Seneca also provided evidence that the selenium standard is attained in the upper portions of the two creeks in the segment. The Commission did include the lower portion of the creeks (Sage Creek below Routt County Road 51D and Grassy Creek below Routt County Road 27A), on the 303(d) List for dissolved selenium.
BASIS AND PURPOSE (Monitoring and Evaluation List)
A.	Introduction
This regulation updates Colorado’s Monitoring and Evaluation List to reflect additional water quality information available since the Regulation was promulgated in 2006.
B.	List Development
The statement of basis and purpose for Regulation No. 93 contains a description of how the lists were developed. 
C.	Prioritization and Scheduling
The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle.  Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.
D.	Segment Specific Issues
1.	Lower Dolores segment 3 (COGULD03):  The Commission approved resegmentation of Lower Dolores segment 3 at the Regulation 35 Rulemaking Hearing in June 2006.  The resegmentation was based on the Division’s investigation identifying Salt Creek draining the Sinbad Valley.  The Sinbad Valley is identified by the Colorado Geological Survey as a graben or a collapse feature that formed in response to salt migration and dissolution beneath the area.  Based on this information the selenium and zinc standards for the new Salt Creek segment were set at ambient conditions.  The Division proposed to delete this from the M&E List based on attainment of the new ambient standards.  The Commission removed this segment from the M&E List. 
2.	Bear Creek segment 1a (COSPBE01a):  This segment was removed from the M&E List based on assessment of annual fish surveys, water quality parameters and temperature data.  It is noted that Bear Creek has seen significant improvement but still requires continued cooperative efforts by the Division, DOW, the Bear Creek Watershed Authority, Trout Unlimited and others to prevent future impairment or re-listing.
3.	Blue River segment 3 (COUCBL03):  The Commission has included Gold Run Gulch below Jessie Mine (for cadmium and zinc) and the South Branch Swan River below Royal Tiger Mine (for zinc) on the 2006 Monitoring and Evaluation List.  The Royal Tiger Mine and the Jessie Mine are both part of a CERCLA remediation effort completed in 2007.  Remediation results with respect to water quality are not yet available.  In the past the Commission did not intend by including these waters on the Monitoring and Evaluation List to conclude that any actions other than those completed CERCLA-related activities are necessary or appropriate at this site.  The status of those efforts will be reviewed during the next update of this list.
4.	White River segment 16 (COLCWH16): The Commission has included Ryan Gulch on the Monitoring and Evaluation List for E. coli.  Shell had argued that Ryan Gulch should not be included on the Monitoring and Evaluation List for E. coli due to the lack of more than a single sample and because “the segment does not appear to support classification as recreation class 2.”  The Commission notes that placement of the water on the Monitoring and Evaluation List does not indicate a finding that Ryan Gulch is in non-attainment with the assigned Recreational Use, only that more data is needed to accurately assess the attainment status.  Further, the Commission would note that alternate Recreation Use designations have more stringent E. coli standards then that assigned with the current Recreation Use designation.  
5.	Upper Yampa segment 13d, Dry Creek (COUCYA13d):  The Division proposed listing this segment due to exceedances of the lead standard. Seneca provided evidence that the lead standard is attained within the upper portion of this segment. The Commission included the lower portions of the segment (below Routt County Road 53 (Sec. 22, T6N, R88W)), on the 2008 M&E List for dissolved lead.
6.  	Uncompahgre segment 3b, Ridgeway Reservoir (COGUUN03b):  Listing methods for temperature in lakes were changed in the Section 303(d) Listing Methodology – 2008 Listing Cycle to reflect changes in the temperature standards in Regulation No. 31.  In the Listing Methodology (p. 25) it states:  “If the refuge is not adequate because of low dissolved oxygen, the lake or reservoir may be listed as impaired for dissolved oxygen rather than for temperature.” The Division proposed a few segments for the M&E List that are listed for dissolved oxygen due to exceedances of temperature in the epilimnion where there was not adequate refugia in the lower levels of the lake or reservoir.  Ridgeway Reservoir was one of those segments.  The data showed that the temperature standard was exceeded in the epilimnion on 7/21/05.   An adequate refuge from high temperatures in the epilimnion was not present on that day due to inadequate dissolved oxygen in the lower portion of the lake.  Due to confusion that this type of listing caused, the parameter notation in Regulation No. 94 was changed to indicate that the D.O. listing was due to exceedances of the temperature standard.  The Commission added Ridgeway Reservoir; segment COGUUN03b, to the M&E List for “D.O. (temperature)”.
7.	Fountain Creek segment 2a (COARFO02a):  Fountain Creek segment COARFO02a includes the mainstem from its confluence with Monument Creek to the State Highway 47 Bridge.  This segment was assigned an ambient-based chronic selenium standard of 8.0 ug/L during the Arkansas River Basin RMH in 2007.  The Aquatic Life Use-based acute standard was set at TVS.  Two acute exceedances were found during the data assessment for this rulemaking hearing that could place this segment on the 303(d) List.  Further investigation of these acute exceedances showed discrepancies in the USGS and the WQCD data.  The Division, as well as Colorado Springs, believed that because of the inconsistent nature of this data it may not be representative, and together the parties will investigate the validity of these data.  For this reason, the Commission placed this segment on the M&E as opposed to the 303(d) List until further study of selenium in this segment can take place.
8.	Upper Colorado segment 2, Shadow Mountain Reservoir (COUCUC02):  The Division originally proposed to include Shadow Mountain Reservoir on the 2008 303(d) List for dissolved oxygen.  In their RPHS, Northern opposed the listing of Shadow Mountain for dissolved oxygen on the 303(d) List.  They stated that the data was not representative because it was not spatially distributed, it did not have temporal variability, and it followed a temporary event, namely fall turn over following a historic drought. The Division disagreed regarding the representative nature of the sampling program but points out that there are questions about the validity of the September 2003 sample profile that was evaluated.  For example, the Division believed that D.O. readings taken on September 16, 2003 may have been a calibration error.  Moreover, that was the only reading that exceeded the standard during the entire period of record and thus may not have been representative.  For these reasons the reservoir was placed on the M&E List as opposed to the 303(d) List until further evaluation can take place.  
9.	Upper Colorado segments 6 and 8, Camp Cr, Jones Gulch, Keystone Cr, and Mozart Creek (COUCBL06 and COUCBL08):  During the 2004 rulemaking process, the four identified tributaries in these two segments were placed on the M&E List based upon measured pH levels during one spring one runoff season when pH levels are expected to be relatively low due to natural causes.  Subsequent water quality monitoring conducted over a period of four years has found that these streams meet the pH standards and have 15th percentile values that are above the minimum 6.5 s.u. pH standard.  Based upon these findings, the Commission removed segments COUCBL06 and COUCBL08 from the M&E List.
10.	Upper Colorado segment 10 (COUCUC10):  The Division proposed that segment COUCUC10 be placed on the M&E List for copper based on data from WQCD station 12193, located on the Fraser River at the Town of Fraser.  Additional stations were assessed on this segment.  The Districts questioned the data used in the assessment and upon reevaluation of data for five stations along the Fraser River, the Division revised its proposal to only list a portion of the segment on the M&E List.  The WQCC placed the Fraser River from the Town of Fraser to the confluence with the Colorado River on the M&E List based on this data analysis.  The Division will work with the Grand County Districts and the Grand County Water Information Network (GCWIN) to collect more data and look into copper issues on the Fraser River.
PARTIES TO THE RULEMAKING HEARING
1.	The Metro Wastewater Reclamation District
2.	Bear Creek Watershed Association
3.	Keystone Resort
4.	City of Colorado Springs and Colorado Springs Utilities
5.	CAM-Colorado LLC and CAM Mining LLC
6.	Colorado Division of Wildlife
7.	Southeastern Colorado Water Conservancy District
8.	Shell Frontier Oil and Gas, Inc.
9.	The Grand County Water and Sanitation District #1, the Winter Park West Water and Sanitation District, the Fraser Sanitation District and the Winter Park Sanitation District
10.	Trout Unlimited, Colorado Trout Unlimited, and the Evergreen Chapter of Trout Unlimited
11.	Northern Colorado Water Conservancy District
12.	Seneca Coal Company
13	Colorado River Water Conservation District
14.	U.S. Environmental Protection Agency, Region 8
15.	City of Black Hawk and Black Hawk/Central City Sanitation District
16.	Cripple Creek & Victor Gold Mining Company
17.	Town of Minturn
18.	Homestake Mining Company of California
19.	CBS Operations Inc
93.13	STATEMENT OF BASIS, SPECIFIC STATUTORY AUTHORITY AND PURPOSE; FEBRUARY, 2010 RULEMAKING, EFFECTIVE DATE OF APRIL 30, 2010
The provisions of C.R.S. 25-8-202(1)(a), (b) and (i), (2) and (6); 25-8-203; 25-8-204; and 25-8-401; 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.	Consolidation of Regulations #93 and #94
Prior to the 2010 listing cycle, Colorado’s list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads was set forth in this Regulation #93, and Colorado's Monitoring and Evaluation List was set forth in Regulation #94.  In this hearing, the Commission has approved the Division staff proposal to combine both lists into Regulation #93, and to repeal the former Regulation #94.  The primary benefit of combining the regulations is to make the status of water segments in Colorado easier to understand by setting forth both lists in one table.  This new structure will also make it easier to understand proposed revisions to either list during future rulemaking hearings.  These benefits will be seen by the Division, the Commission and interested stakeholders.  
Both regulations were heard by the Commission at the same rulemaking hearings in the past and decisions were made for both regulations at the same time.  One reason for maintaining separate lists in the past is that Colorado’s list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads is subject to EPA approval, while Colorado's Monitoring and Evaluation List is not.  Although the Commission is now combining both lists into one regulation for simplicity and ease of use, it will continue to be only the list of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads that requires EPA approval.  In submitting the revised “Section 303(d) List” to EPA, the Commission will note that only that list is submitted for approval and that the separate Colorado Monitoring and Evaluation List is maintained as state-only information.
B.	Revisions to 303(d) List
1.	Introduction
This regulation updates Colorado’s List of Water-Quality-Limited Segments Requiring Total Maximum Daily Loads (“TMDLs”) to reflect additional water quality information available since the Regulation was promulgated in 2008.  This list was prepared to fulfill section 303(d) of the federal Clean Water Act (“Act”) which requires that states submit to the U.S. Environmental Protection Agency (“EPA”) a list of those waters for which technology-based effluent limitations and other required controls are not stringent enough to implement water quality standards.
2.	List Development
a.	Listing Methodology
The “Section 303(d) Listing Methodology - 2010 Listing Cycle” contains a description of the listing process, the criteria for listing, and the criteria for determination of TMDL priority.  The Listing Methodology was developed through a public process and finalized as a policy at a Water Quality Control Commission administrative action hearing on May 11, 2009.
This Listing Methodology sets forth the criteria that generally were used to make decisions regarding which waters to include on the 2010 Section 303(d) List and the 2010 M&E List.  However, this methodology was not adopted by the Commission as a rule.  The Commission therefore has the flexibility to take into account other appropriate factors in making site-specific listing decisions.
b.	Information Considered
The Commission has considered all existing and readily available information in developing the 2010 Section 303(d) List.  In determining whether data and information are existing and readily available, it has taken into account such data and information as the Division has utilized in the preparation of those identification processes, calculations and models referenced in 40 CFR §130.7(a)(5)(i), (ii) and (iv) and that credible data and information presented in a readily usable format and submitted in reports provided to the Division as referenced in 40 CFR §130.7(a)(5)(iii).  In addition, the Commission accepted credible data and information that was submitted in accordance with the listing process schedule, whether submitted by EPA or any other interested party.  The Division also continues to independently collect and analyze new data on a rotating basin basis as part of its triennial review efforts and will utilize such data and information in making future listing determinations.  Existing data which was not brought forward through one of the above mechanisms or otherwise presented to the Commission in accordance with the schedule was not treated as "readily available" for purposes of making the 2010 listing decisions.  Such information will be considered in the next listing cycle.
c.	Data Quality
In the Division's Quality Management Plan 2007 for the Collection and Utilization of Environmental Data, the WQCD states that "It is the expressed goal of the Division to use only those analytical data that are both reliable and have a defined level of quality."  In order to meet this goal, the WQCD required that all information submitted in response to its August 2009 call for data have a certification of quality included with the data.  All of the information received for this data call that was utilized to develop assessments for this rulemaking hearing had a quality certification submitted or has been identified as not having this certification.  Only a small fraction of the data is not certified.
3.	Prioritization
The objective of prioritization is to identify those waterbody segments where the Division and the public should concentrate their resources.  Priorities of High, Medium and Low were established according to section IV. of the 2010 Section 303(d) Listing Methodology.  
4.	Fish Consumption Advisory Listings
The 2010 Section 303(d) Listing Methodology, states:
Fish Consumption Advisories are issued by the Colorado Department of Public Health and Environment (“CDPHE”) in instances where analysis of fish tissue samples provides documentation of a public health risk.  Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified.  
The Commission has included 17 segments on the 2010 303(d) List for non-attainment of the aquatic life use due to mercury fish consumption advisories for 22 lakes or reservoirs.  The Commission also included one listing based on non-attainment of the aquatic life use due to a PCE fish consumption advisory in Willow Springs Ponds, Fountain Creek, Segment 7a.
The following segments have been added to the 2010 303(d) List due to new Fish Consumption Advisories:
▪	Lower Gunnison Segment 4b, Juniata Reservoir
▪	Lower Colorado Segment 20, Rifle Gap Reservoir
▪	San Juan Segment 6a, Echo Canyon Reservoir
▪	Upper Colorado Segment 12, Lake Granby
▪	Yampa River Segment 2b, Elkhead Reservoir, Catamount Lake
5.	New Table Value Standards 
Cadmium and Zinc:  As part of the Basic Standards hearing of 2005, new zinc and cadmium table values were adopted. The acute and chronic zinc and cadmium equations in each basin were modified to conform to Regulation No. 31 over the last four years.  An increase in cadmium listings were the result of a more stringent cadmium standard.  
The following segments were added to the 303(d) List for cadmium:
▪	Big Thompson Segment 2
▪	Clear Creek Segments 2a, 2b, 2c, 9b, 11, 13b
▪	Cache la Poudre Segment 7
▪	Upper South Platte Segments 2b, 2c, 5a, 5b, 15
▪	Blue River Segment 12
▪	Eagle River Segment 5c
▪	Upper South Platte Segments 3 (Hawkins Gulch), 5a
Temperature:  As part of the Temperature Standards hearing of 2007, new temperature table values were adopted. The acute and chronic temperature standards in the Upper and Lower Colorado and the South Platte River Basins were modified to conform to Regulation No. 31 over the last two years.  
The following segments were added to the 303(d) List for temperature:
▪	Upper Colorado Segments 3, 4, 7b and 10c
6.	Listings Due to Exceedances of the Secondary Water Supply Standards
For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III.  For dissolved iron this value is 300 ug/l.  For manganese this value is 50 ug/l.  For sulfate this value is 250 ug/l.  
The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III.  The following segments were proposed for listing based on exceedances of the standards:
▪	Lower South Platte Segment 1: Manganese
7.	Relisting Segments with Approved TMDLs Due to Standards Changes
Once a TMDL has been completed, impaired waters are removed from the 303(d) List and placed into Integrated Reporting Category 4a.  TMDLs are written to the adopted standards at the time they are submitted to EPA.  As standards are periodically reviewed they may become more stringent.  In these cases the TMDL may no longer be protective of the current standards.  The Division reviewed segments where both TMDLs have been written and new, more restrictive standards have been adopted by the Commission.  The Commission has relisted the following segments:
South Platte Basin: 
▪	Clear Creek Segments 09b, 11, and 13b: Cadmium
▪	Clear Creek Segment 02b: Zinc
▪	Upper South Platte Segments 2b, 2c and 15: Cadmium
8. 	Delisting of Segments with Recently Approved TMDLs
The Division submitted 64 TMDLs to EPA in the last biennium that have been approved.  The following segments and parameters have been removed from the 303(d) List:
▪	Upper Arkansas Segment 2a: Zinc
▪	Upper Arkansas Segments 2b, 2c and 3: Cadmium and Zinc
▪	Upper Arkansas Segment 5: Lead and Cadmium
▪	Upper Arkansas Segment 7: Zinc
▪	Upper Arkansas Segment 11: pH, Aluminum, Cadmium, Copper and Zinc
▪	Upper Arkansas Segment 12a: Lead and Zinc
▪	San Miguel Segment 3a: Zinc
▪	San Miguel Segment 3b: Cadmium and Zinc
▪	San Miguel Segments 6a and 6b: Zinc
▪	Uncompahgre Segments 2, 3a, 6a: Cadmium, Copper, Iron, and Zinc 
▪	Rio Grande Segment 4:  Cadmium and Zinc 
▪	Rio Grande Segment 30, Sanchez Reservoir: Aquatic Life Use (Hg FCA)
▪	Closed Basin Segment 9a: Cadmium
▪	Closed Basin Segment 9b: Copper
▪	Dolores River Segment 9: Cadmium and Zinc
▪	Boulder Creek Segment 4a: pH, Cadmium, Copper and Zinc
▪	Clear Creek Segment 2: Copper and Zinc
▪	Clear Creek Segment 3a: Zinc
▪	Clear Creek Segment 3b: Lead and Zinc
▪	Clear Creek Segment 9a: Copper
▪	Clear Creek Segment 9b: Copper, Lead and Zinc
▪	Clear Creek Segment 11: Lead and Zinc
▪	Clear Creek Segment 13b: Total Recoverable Iron, Manganese, Zinc, and Aquatic Life Use
▪	Upper South Platte Segment 4: Copper
▪	Upper South Platte Segment 5b: Zinc
▪	Blue River Segment 6: pH, Cadmium, Copper, Lead and Zinc
▪	Blue River Segment 7: pH, Cadmium, Copper, Lead, Manganese and Zinc
▪	Blue River Segment 12: Zinc
▪	Eagle River Segment 5a: Copper and Zinc
▪	Eagle River Segment 5b: Zinc
▪	Eagle River Segment 5c: Zinc
▪	Eagle River Segment 7b: Copper and Zinc
9. 	Delisting of Segments where Water Quality is Currently Meeting Standards
As additional water quality data is collected and assessed, new data may show attainment of the standards.  The following segments and parameters have been removed from the 303(d) List due to attainment of current water quality standards:
▪	Upper Arkansas Segment 2a:  NO3
▪	Uncompahgre River Segment 14, Sweitzer Lake: D.O.
▪	Lower Colorado Segment 3: Total Recoverable Iron
▪	White River Segment 13b, Corral Creek: Selenium
▪	La Plata Segment 4a: Zinc
▪	Rio Grande Grande Segment 9 (Beaver Creek Reservoir): D.O.
▪	Closed Basin Segment 6, San Luis Lake: D.O.
▪	Cherry Creek Segment 2, Cherry Creek Reservoir: chlorophyll a
▪	Upper Colorado Segment 7a: Total Recoverable Iron
▪	Yampa River Segment 16: Total Recoverable Iron
▪	Lower Yampa Segment 20: E. coli
▪	Cache La Poudre Segment 14 (Horsetooth Reservoir):  D.O.
▪	Upper Colorado Segment 5 (Wolford Reservoir):  D.O.
10. 	Dissolved Oxygen Standard in Lakes and Reservoirs
In 2008, the Commission directed the Division to work with outside parties and stakeholders on changes to the Listing Methodology with regards to the assessment of dissolved oxygen in lakes and reservoirs.  Refinement of assessment methods were discussed in workgroup meetings and updates to the dissolved oxygen methods were included in the 2010 Listing Methodology.  
The revised 2010 Listing Methodology states that if the average temperature in the epilimnion of lakes and reservoirs exceeds the temperature standard, temperature and dissolved oxygen below the epilimnion will be evaluated for adequate refuge.  Refuge is defined as the concurrent attainment of the temperature and dissolved oxygen standard at lower depths.  If adequate refuge is not present in a single profile, the segment is listed as impaired for dissolved oxygen rather than for temperature. The Commission added the following segments to the 303(d) List due to exceedances of the temperature standard where adequate refuge was not found:
▪	Lower Arkansas Segment 5b, Trinidad Lake
▪	Clear Creek Segment 17a, Arvada Reservoir
The Listing Methodology also states that if the average dissolved oxygen concentration in the epilimnion falls below the standard in any profile, the lake will be placed on the 303(d) list.  Where the dissolved oxygen standard is not attained in the metalimnion, but it is attained in the epilimnion, the lake may be placed on the M&E list, according to the Listing Methodology.  The Commission added 25 new lakes to the M&E list due to exceedances in the dissolved oxygen standard in the metalimnion.  The following twelve lakes and reservoirs were added to the 303(d) List due to exceedances in the dissolved oxygen standard in the epilimnion:
▪	Cache la Poudre Segment 20, Seaman Reservoir
▪	Middle South Platte Segment 4, Milton Reservoir
▪	Middle South Platte Segment 7, Prospect Lake
▪	Upper South Platte Segment 17a, Berkeley Lake, Duck Lake
▪	Upper South Platte Segment 17b, Sloan’s Lake
▪	Upper South Platte Segment 23, Barnum Lake, Garfield Lake, Harvey Lake, 	Parkfield Lake and Houston Lake
▪	Upper Colorado Segment 2, Shadow Mountain Lake		
The dissolved oxygen standard is slated for revisions in the 2010 Basic Standards and Methodology, Regulation No. 31, rule-making hearing in June 2010.  The attainment decision for these lakes and reservoirs may be different when they are reassessed with the revised standard.  
11.	Seasonal Listings of E. Coli
The 2010 Listing Methodology included a provision to allow assessment of the E. coli standard on a seasonal basis.  The Division proposed the following segments be placed on the 303(d) List based on seasonal impairments of the E. coli standard:
▪	Arkansas River Basin, Fountain Creek Segments 2b and 6
▪	South Platte Basin, Big Thompson Segment 9
▪	South Platte Basin, Cache la Poudre Segments 12 and 13a
▪	South Platte Basin, Bear Creek Segment 2
▪	South Platte, Clear Creek Segment 15
▪	South Platte, Upper South Platte Segment 16c:  Harvard, West Harvard and Lakewood Gulches
The Commission adopted all proposed seasonal listings onto the 303(d) List as proposed by the Division.
12. 	Listing of Segments where Water Quality is not Meeting Standards not Identified Above
The following segments were added to the 303(d) List due to exceedances of water quality standards not identified above:
▪	South Platte, Bear Creek Segment 5: Swede Gulch/Kerr Gulch, E. coli 
▪	South Platte, Cherry Creek Segment 3: E. coli and Se
▪	South Platte, Clear Creek Segment 2b: Zn
▪	South Platte, Clear Creek Segment 3a: Cu
▪	South Platte, Clear Creek Segment 9a: Silver Creek, Cu and Pb
▪	South Platte, Clear Creek Segment 9b: pH 
▪	Upper Gunnison Segment 29a, Deadman Gulch: pH, Cd, Cu, Mn, Zn, Fe(Trec)
▪	Lower Colorado Segment 10:  Se
▪	Lower Colorado, White River Segment 9d: Se
▪	South Platte, Bear Creek Segment 1c (Bear Creek Reservoir): Chl a, Phosphorus
▪	South Platte, Bear Creek Segment 5: E. coli
▪	South Platte, Boulder Creek Segment 2a, 2b and 3: Cu
▪	South Platte, Boulder Creek Segment 8: Se
▪	South Platte, Boulder Creek Segment 9: As
▪	South Platte, Big Thompson Segment 2: Cu, Zn
▪	South Platte, Big Thompson Segment 3, 6, 7: Cu
▪	South Platte, Big Thompson Segment 4a, 4b: Se
▪	South Platte, Big Thompson Segment 8: D.O
▪	South Platte, Big Thompson Segment 16 (Lake Estes): Cu
▪	South Platte, Cache La Poudre Segment 7: Pb
▪	South Platte, Cache La Poudre Segment 11: Se
▪	South Platte, Lower South Platte Segment 1: Se, Mn
▪	South Platte, Lower South Platte Segment 2b: Se
▪	South Platte, Middle South Platte Segment 1a: E. coli
▪	South Platte, Middle South Platte Segment 1b: Se
▪	South Platte, Middle South Platte Segment 4 (Barr and Milton Reservoirs): NH3
▪	South Platte, Middle South Platte Segment 7 (Horse Creek Reservoir and Prospect Lake): pH, NH3
▪	South Platte, Republican Segment 4: E. coli
▪	South Platte, St. Vrain Segment 2a: Zn
▪	South Platte, St. Vrain Segment 4c: Cu, As
▪	South Platte, Upper South Platte Segment 2c: Zn
▪	South Platte, Upper South Platte Segment 3 (Hawkins Gulch): Se
▪	South Platte, Upper South Platte Segment 3 (Horse Creek): D.O., Fe(trec)
▪	South Platte, Upper South Platte Segment 3 (West Creek): As, Hg
▪	South Platte, Upper South Platte Segment 3 (Goose Creek): D.O.
▪	South Platte, Upper South Platte Segment 3 (Trail & Wigwam Creeks): Fe(trec)
▪	South Platte, Upper South Platte Segment 4: pH
▪	South Platte, Upper South Platte Segment 5a: Cu, Zn
▪	South Platte, Upper South Platte Segment 5c: NH3
▪	South Platte, Upper South Platte Segment 14: As
▪	South Platte, Upper South Platte Segment 17a (Berkeley Lake): As
▪	South Platte, Upper South Platte Segment 23 (Barnum Lake): E. coli
▪	Upper Colorado,Yampa River Segment 13b: Total Recoverable Iron
13.	Segment- Specific Issues
a.	Upper South Platte Segment 15 and Middle South Platte Segment 1a – Category 4b Demonstration Plan
Metro Wastewater Reclamation submitted a Category 4b Demonstration Plan to the Division for two segments on the mainstem of the South Platte: Upper South Platte Segment 15 and Middle South Platte Segment 1a.   Category 4b is an alternative to listing an impaired segment on the 303(d) List.  A Category 4b Demonstration Plan, when implemented, must ensure attainment with all applicable water quality standards through pollution control mechanisms within a reasonable time period.  This plan was accepted by the U.S. Environmental Protection Agency prior to the development of the Division's proposed 303(d) List.  As a result, the Division did not include these segments in their proposal. No further discussion or comments were received by other parties.  The Commission did not include Upper South Platte Segment 15 and Middle South Platte Segment 1a on the 303(d) List for ammonia and nitrate, for which the Category 4b Demonstration Plan was written.   The Commission expects that after a reasonable period of time as defined in the Category 4b Demonstration Plan, water quality will be reexamined on these segments.  If water quality standards are not achieved at this time the segment will be considered impaired and placed on the 303(d) List.
b.	South Platte River (COSPUS14 and COSPUS15) - Trash
Two proposals were originally submitted in prehearing statements by P.U.R.E. and Wild Earth Guardians to list the South Platte River from Bowles Avenue to the confluence of Sand Creek as impaired for trash.  Wild Earth Guardians withdrew their proposal but P.U.R.E maintained their proposal.  The Division met prior to the Rulemaking hearing with representatives of P.U.R.E and discussed the issue.  The Division maintained that a method to determine impairment for trash did not exist and that this must be determined before a decision of impairment can be made.  The Division and P.U.R.E agreed to begin to address this issue in the 2012 303d Listing Methodology development stakeholder process that is to begin in the summer of 2010.   
After listening to all of the testimony on this topic, the Commission took no action on listing these segments for trash at this time.  It is expected that P.U.R.E, the Division and other stakeholders will work collaboratively to develop an appropriate methodology for determining impairment for trash through the 2012 303d Listing Methodology development process and other appropriate collaborative processes.    
c.	Muddy Creek (COUCUC07b) – Temperature
The Division proposed to list Muddy Creek (COUCUC07b) on the 303(d) List for temperature.  The River Water Conservation District (River District) opposed this listing stating that exceedances at an upper station were due to a temporary construction at the outlet of Wolford Reservoir.  Exceedances were still found at the lower station.  The Commission adopted the Division’s alternate proposal to include the upper portion from Wolford Reservoir to Cow Gulch on the M&E List the and lower portion from Cow Gulch to the Colorado River on the 303(d) List.  
d.	Colorado River (COUCUC03) – Temperature
The Division proposed to place all of the Colorado River mainstem from Lake Granby to the Roaring Fork River (COUCUC03) on the 303(d) List for temperature exceedances.  Northern Colorado River Conservancy District (Northern) proposed an alternative portion of 578 Road bridge to the William Fork confluence.  The Commission found that the portion that Northern recommended, omitted sites with exceedances both above and below their recommended portion.  To encompass the entire scope of temperature exceedances, the Commission adopted the portion from 578 Road to immediately above the confluence with the Blue River.
e.	Lower Colorado Segment 2b – Selenium
In 2008, the Commission adopted only the portion at Humphrey Backwaters Area onto the 303(d) List for selenium.  For this cycle, the Division proposed to list the entire segment for selenium.  The City of Grand Junction and the River District opposed this listing claiming that the Riverwatch data used in the assessment was not representative or of good quality.  The Division supported the quality of this data but since the data was older than five years, the Division agreed that additional data collection was needed before a decision to list the entire segment could be made.  The Commission placed the remainder of this segment on the M&E List while leaving the Humphrey Backwaters Area on the 303(d) List.  Grand Junction and the River District have offered to collect data throughout the segment before the next 303(d) rulemaking hearing in 2012.  
f.	Upper South Platte Segment 16c
Upper South Platte Segment 16c is an all tributary segment and the Division proposed to place the entire segment on the 303(d) List for exceedances of E. coli and selenium.  
E. coli:  Denver Environmental Health (DEH) opposed listing all tributaries for both parameters.  DEH put forward an alternative proposal for E. coli on this segment with some tributaries to be included on the 303(d) annually, some listed seasonally and one for the M&E List based on the attainment conclusions for each tributary individually.  Those tributaries attaining the standard were not proposed for either list.  The Division reviewed their proposal and agreed that it is a reasonable approach for E. coli. The Commission adopted the alternative proposal as presented by DEH.
Selenium:  DEH also asked that the Commission to only list those tributaries that have selenium data on the 303(d) List.  The Division opposed this alternative proposal.  The Division pointed out that unlike the data found on E. coli for these tributaries, everywhere that selenium data was collected, exceedances were found.  The Commission chose to place the entire segment on the 303(d) List for selenium.
g.	Fountain Creek Segments 2a and 2b
The Division originally proposed to change the E. coli listing on Segment 2a from annual to seasonal (May through October) and to add Segment 2b to the 303(d) List seasonally.  Rocky Mountain Environmental Labor Coalition/Sierra Club and Bill Thiebaut, District Attorney for the 10th Judicial District, asked that the listing be considered for the entire year for both segments as there are recreation uses in Fountain Creek year round.  Through further investigation and reassessment of the data by the Division and the  parties, data indicates that in Segment 2a, the E. coli standards are exceeded annually as opposed to seasonally as originally thought.  In Segment 2b the exceedances were only found from May – October. The Commission chose to retain the listing on Segment 2a for E. coli annually and to add Segment 2b to the 303(d) List from May-October.  
The Division also originally proposed to remove the selenium listings on Segment 2a and 2b.  This proposal also received opposition from RMELC/Sierra Club and Bill Thiebaut as there are ongoing studies regarding selenium in Fountain Creek.  Colorado Springs supported the Division’s original proposal.  Further investigation of acute selenium exceedances in Segment 2b in July 2005 prompted the Division and EPA to change their position prior to the hearing to retain this segment on the 303(d) List.  The Commission agreed that this listing should remain on the 303(d) List until further evidence exist to support delisting. The Commission agreed with the Division that the data is meeting the ambient based standards in Segment 2a and removed the M&E listing for that segment.
h.	Bear Creek (COSPBE05) – Swede Gulch and Kerr Gulch  -E. coli
The Division originally proposed to list only Swede Gulch based on the Division’s sampling at the mouth of the gulch.  The Bear Creek Watershed Association (BCWA) identified this sampling location as Kerr Gulch.  The Division used USGS and other maps indicating this as Swede Gulch.  The Colorado Department of Transportation (CDOT) and residents identify this as Kerr Gulch.  The Division met with the BCWA and agreed that the watershed, whatever the name of the stream, may be impacted by septic systems and livestock.  The BCWA agreed to the development and implementation of a monitoring plan in the watershed to identify E. coli sources.  The Division agreed that if the plan were implemented the priority of the listing should be changed from high to low to allow time for sampling and development of stakeholder involvement.  The Commission agreed with the Division and the BCWA’s plan for Swede Gulch and Kerr Gulch.
i.	Clear Creek (COSPCL14b) – Manganese
The Division proposed to add manganese to the list of impairment parameters of Clear Creek segment 14b.  During the 2009 South Platte River Basin RMH a new site-specific manganese standard was established for the segment.  In the development of the new site-specific standard for segment 14b, data from both Clear Creek segments 14a and 14b were combined to determine a single standard for both segments.  This procedure was used since segment 14a has very limited data and it was felt averaging would establish a more realistic standard.  As it turns out when segment 14b only data is assessed against the new standard developed using data from both segments, the few samples from segment 14a with a lower ambient manganese concentration skewed the development of the site-specific standard enough that segment 14b data exceeds the new standard.
Based on the fact that the segment 14b site-specific standard was developed using data from the upstream segment it is not possible to evaluate if the segment is in attainment of the manganese standard.  The proper site-specific standard indicating ambient conditions should be equivalent to the current assessment value and would not indicate impairment since they are the same dataset.
After reviewing the development of the segment 14b site-specific manganese standard, the Division agreed with MillerCoors that the Clear Creek segment should not be listed for exceeding the manganese standard.  The Commission agreed with the Division and MillerCoors that Clear Creek segment 14b should not be listed for manganese.
j.	Juniata Reservoir (COGULG04a)
The Division originally proposed to list Juniata Reservoir on the 303(d) List for impairment of the Aquatic Life Use due to a Fish Consumption Advisory (FCA).  A mercury FCA was issued for Juniata Reservoir in 2009.  The Section 303(d) Listing Methodology 2010 Listing Cycle states at III.D.6 “Issuance of a FCA by CDPHE indicates impairment of an Aquatic Life Use classification for any waters so classified.”  The City of Grand Junction and Colorado Division of Wildlife proposed to either close the reservoir or change the reservoir to “catch and release” in order for the Division to remove the FCA and therefore remove the basis for inclusion on the 303(d) List.  The Division stated that the FCA would not be lifted if the reservoir changed to catch and release and the only way that the FCA could be lifted at Juniata is if the reservoir was completely fenced and fishing access was prohibited.  At the time of the hearing, no action had been taken and the FCA was still in effect.   Therefore the Commission chose to add this segment to the 303(d) List.
k.	Marston Reservoir (COSPUS22)
The Division proposed that Marston Reservoir as part of COSPUS22 be placed on the M & E List for non-attainment of the DO standard in the metalimnion.  The Denver Water Board argued that Marston was not waters of the state and was not used for aquatic life uses.  There was discussion about what constitutes waters of the state and it was decided that that decision was not appropriate for this hearing, since this hearing addresses all waters for which classifications and standards have been adopted.  The Commission decided to include Marston Reservoir on the 2010 M & E List because it fits within the description of waters in Upper South Platte segment 22.
C.	Revisions to Monitoring and Evaluation List
1.	Introduction
This regulation updates Colorado’s Monitoring and Evaluation List (M&E List) to reflect additional water quality information available since the Regulation was promulgated in 2008.
2.	List Development
See the discussion of list development under subsection B.2 above. 
3.	Prioritization and Scheduling
The Division remains committed to establishing a plan for monitoring and evaluating these water bodies prior to the list submission date for the subsequent listing cycle.  Further, the Commission has committed to determining their appropriate status (as either impaired or fully supporting) within ten years of their placement on the M&E List.
4.	Data Quality
See the discussion of data quality under subsection B.2.c above.
5.	New Table Value Standards 
Cadmium and Zinc:  As part of the Basic Standards hearing of 2005, new zinc and cadmium table values were adopted. The acute and chronic zinc and cadmium equations in each basin were modified to conform to Regulation No. 31 over the last four years.  An increase in cadmium listings were the result of a more stringent cadmium standard.  
The following segments were added to the M&E List for cadmium:
▪	Gunnison River, San Miguel Segment 3a
▪	South Platte, Boulder Creek Segment 14, Barker Reservoir
▪	Boulder Creek Segments 2a, 2b, 3, 9 10 and 14 
▪	Clear Creek Segment 6, Hoop Creek
▪	Cache la Poudre Segment 13a
▪	Upper South Platte Segment 3, Hawkins Gulch
▪	Cache La Poudre Segment 9
6.	Listings Due to Exceedances of the Secondary Water Supply Standards
For the secondary water supply standards of dissolved iron, manganese and sulfate, the less restrictive of the following two options will apply as the numeric standard: existing quality as of January 1, 2000 or the table value criteria in Regulation No. 31, Tables II and III.  For dissolved iron this value is 300 ug/l.  For manganese this value is 50 ug/l.  For sulfate this value is 250 ug/l.  
The Division evaluated the water quality as of January 1, 2000 to determine in some cases where standards exceeded the water supply criteria in Tables II and III.  The following segments were proposed for listing based on exceedances of the standards:
▪	Upper Colorado, Yampa River Segments 2a: Manganese
▪	Upper Colorado, Yampa River Segments 3: Manganese and Dissolved Iron
7. 	Delisting of Segments where Water Quality is Currently Meeting Standards
As additional water quality data is collected and assessed, new data may show attainment of the standards.  The following segments and parameters have been removed from the M&E List due to attainment of current water quality standards:
▪	Fountain Creek Segment 2a: Selenium
▪	Fountain Creek Segment 3, Bear Creek and Cheyenne Creek: Sediment
▪	Middle Arkansas Segment 14: E. coli
▪	Upper Arkansas Segment 5, Turquiose Lake: D.O.
▪	Upper Arkansas Segment 13: Sediment
▪	Lower Colorado Segment 4a: Selenium
▪	Lower Colorado Segment 11h: Total Recoverable Iron
▪	Lower Colorado Segment 13b: D.O. and E. coli
▪	St. Vrain Segment 2: Sediment
▪	St. Vrain Segment 3: E. coli
▪	Upper South Platte Segment 2a: Sediment
▪	Upper South Platte Segment 3: Sediment and Temperature
▪	Upper South Platte Segment 4 (North Fork South Platte and Buffalo Creek): Sediment
▪	Upper South Platte Segment 6a: Sediment
▪	Upper Colorado, Yampa River Segment 3 (First Creek): Sediment
▪	Upper Colorado, Yampa River Segment 19 (Oliver Creek): Sediment
▪	Upper Colorado, North Platte River Segment 4a: Sediment
▪	Gunnison River, Uncompahgre Segment 3b, Ridgway Reservoir: D.O.
▪	Gunnison River, San Miguel Segment 7a: Total Recoverable Iron
▪	Lower Colorado, White River Segment 22: Sediment
▪ 	Upper Colorado, Blue River Segment 18: E. coli
8. 	Segments Moved to the 303(d) List
As additional water quality data is collected and assessed, a segment may be moved from the M&E List to the 303(d) List once the non-attainment is confirmed.  In general, segments with less than 10 data points will be placed on the M&E List until more data is collected.  The following segments and parameters have been moved from the M&E List to the 303(d) List due to additional data collection:
▪	Lower Arkansas Segment 5b: D.O.
▪	San Miguel Segment 3a: Cadmium
▪	Upper Gunnison Segment 29a, Deadman Gulch: Cd, Cu, Mn, Zn, Fe(Trec)
▪	Big Thompson Segment 4b: Selenium
▪	Boulder Creek Segment 8: Selenium
▪	Upper Colorado Segment 12, Shadow Mountain Lake: D.O.
▪	Upper Colorado, Yampa River Segment 3 (Bushy Creek): Sediment
▪	Upper South Platte 5a: Cadmium, copper and zinc
9. 	Dissolved Oxygen Standard in Lakes and Reservoirs
In 2008 the Commission directed the Division to work with parties in 2008 and 2009 on changes to the Listing Methodology in regards to dissolved oxygen.  Refinement of assessment methods were discussed in workgroup meetings and included in the 2010 Listing Methodology.  The dissolved oxygen standard is slated for revisions in the 2010 Basic Standards and Methodology, Regulation No. 31, RMH in June 2010.  
The following segments were added to the M&E List due to exceedances of the dissolved oxygen standard in the metalimnion in at least one profile:
▪	Gunnison River, Uncompahgre Segment 14, Sweitzer Lake
▪	Rio Grande Segment 9, Beaver Creek Reservoir
▪	Big Dry Creek Segment 2, Standley Lake
▪	Boulder Creek Segment 14, Barker Reservoir
▪	Big Thompson Segment 12, Lake Loveland, Horseshoe Lake and Boyd Lake
▪	Big Thompson Segment 14, Lon Hagler Reservoir and Lonetree Reservoir
▪	Cache la Poudre Segment 14, Horsetooth Reservoir
▪	Lower South Platte Segment 3, North Sterling Reservoir
▪	Middle South Platte Segment 4, Barr Lake
▪	Middle South Platte Segment 7, Horse Creek Reservoir
▪	St. Vrain Creek Segment 7, Boulder Reservoir
▪	St. Vrain Segment 9, Union Reservoir
▪	St. Vrain Segment 13, Lake Thomas
▪	Upper South Platte Segment 16b, Aurora Reservoir
▪	Upper South Platte Segment 19, Tarryall Reservoir, Cheesman Reservoir, Elevenmile Reservoir, Spinney Mountain Reservoir
▪	Upper South Platte Segment 22, Marston Reservoir, Quincy Reservoir, 
▪	Upper South Platte Segment 23, Vanderbilt Reservoir
▪	Upper Colorado Segment 5, Wolford Mountain Reservoir
▪	Upper Colorado, Yampa River Segment 2b, Stagecoach Reservoir
PARTIES TO THE RULEMAKING HEARING
1.	Protect Urban River Environments (Confluence Kayaks and Telemark, Colorado Whitewater Association, Denver Trout Unlimited, The Shimoda Group, The Greenway Foundation)
2.	Summit Water Quality Committee
3.	Northwest Colorado Council of Governments
4.	City of Boulder
5.	City of Colorado Springs and Colorado Springs Utilities
6.	City of Aurora
7.	Denver Water
8.	City and County of Denver
9.	Bear Creek Watershed Association
10.	City of Grand Junction
11.	Northern Colorado Water Conservancy District
12.	Metro Wastewater Reclamation District
13.	Alamosa Riverkeeper
14.	Bill Thiebaut, District Attorney for 10th Judicial District, Colorado
15.	Farmers Reservoir and Irrigation Company
16.	Barr Lake and Milton Reservoir Watershed Association
17.	Colorado Division of Wildlife
18.	City of Black Hawk and Black Hawk/Central City Sanitation District
19.	Cherry Creek Basin Water Quality Authority
20.	South Platte Coalition for Urban River Evaluation
21.	Colorado River Water Conservation District
22.	Grand County Water and Sanitation District #1, Winter Park Ranch Water and Sanitation District, Fraser Sanitation District, Winter Park Sanitation District
23.	City of Westminster
24.	The Rocky Mountain Environmental Labor Coalition and the Sierra Club
25.	Colorado Stormwater Council
26.	Seneca Coal Company
27.	Littleton/Englewood Wastewater Treatment Plant
28.	City of Arvada
29.	MillerCoors LLC
30.	Ute Water Conservancy District, acting by and through the Ute Water Activity Enterprise
31.	US Environmental Protection Agency