5 Colo. Code Regs. § 1002-35.5

Current through Register Vol. 47, No. 20, October 25, 2024

Section 5 CCR 1002-35.5 - BASIC STANDARDS

(1)Temperature

All waters of the Gunnison/Lower Dolores River Basins are subject to the following standard for temperature. (Discharges regulated by permits, which are within the permit limitations, shall not be subject to enforcement proceedings under this standard). Temperature shall maintain a normal pattern of diurnal and seasonal fluctuations with no abrupt changes and shall have no increase in temperature of a magnitude, rate, and duration deemed deleterious to the resident aquatic life. This standard shall not be interpreted or applied in a manner inconsistent with section 25-8-104, C.R.S.

(2)Qualifiers

See Basic Standards and Methodologies for Surface Water for a listing of organic standards at 31.11 Table B and metal standards found at 31.16 Table III. The column in the tables headed "Water + Fish" are presumptively applied to all aquatic life class 1 streams which also have a water supply classification, and are applied to aquatic life class 2 streams which also have a water supply classification, on a case-by-case basis as shown in Appendix 35-1. The column in the tables at 31.11 and 31.16 Table III headed "Fish Ingestion" is presumptively applied to all aquatic life class 1 streams which do not have a water supply classification, and are applied to aquatic life class 2 streams which do not have a water supply classification, on a case-by-case basis as shown in Appendix 35-1.

(3)Uranium

(a) All waters of the Gunnison/Lower Dolores River Basin, are subject to the following basic standard for uranium, unless otherwise specified by a water quality standard applicable to a particular segment. However, discharges of uranium regulated by permits which are within these permit limitations shall not be a basis for enforcement proceedings under this basic standard.

(b) Uranium level in surface waters shall be maintained at the lowest practicable level.

(c) In no case shall uranium levels in waters assigned a water supply classification be increased by any cause attributable to municipal, industrial, or agricultural discharges so as to exceed 16.8-30 µg/L or naturally-occurring concentrations (as determined by the State of Colorado), whichever is greater.

(i) The first number in the 16.8-30 µg/L range is a strictly health-based value, based on the Commission's established methodology for human health-based standards. The second number in the range is a maximum contaminant level, established under the federal Safe Drinking Water Act that has been determined to be an acceptable level of this chemical in public water supplies, taking treatability and laboratory detection limits into account. Control requirements, such as discharge permit effluent limitations, shall be established using the first number in the range as the ambient water quality target, provided that no effluent limitation shall require an "end-of-pipe" discharge level more restrictive than the second number in the range. Water bodies will be considered in attainment of this standard, and not included on the Section 303(d) List, so long as the existing ambient quality does not exceed the second number in the range.

(4)Nutrients

Prior to May 31, 2022, interim nutrient values will be considered for adoption only in the limited circumstances defined at 31.17(e). These circumstances include headwaters, Direct Use Water Supply (DUWS) Lakes and Reservoirs, and other special circumstances determined by the Commission. Additionally, prior to May 31, 2017, only total phosphorus and chlorophyll a will be considered for adoption. After May 31, 2017, total nitrogen will be considered for adoption per the circumstances outlined in 31.17(e).

Prior to May 31, 2022, nutrient criteria will be adopted for headwaters on a segment by segment basis for the Gunnison/Lower Dolores River Basin. Moreover, pursuant to 31.17(e) nutrient standards will only be adopted for waters upstream of all permitted domestic wastewater treatment facilities discharging prior to May 31, 2012 or with preliminary effluent limits requested prior to May 31, 2012, and any non-domestic facilities subject to Regulation 85 effluent limits and discharging prior to May 31, 2012. The following is a list of all permitted domestic wastewater treatment facilities discharging prior to May 31, 2012 or with preliminary effluent limits requested prior to May 31, 2012, and any non-domestic facilities subject to Regulation 85 effluent limits and discharging prior to May 31, 2012 in the Gunnison/Lower Dolores River Basin:

Segment	Permittee Name	Facility Name	Permit No.
COGUUG04	Almont Sewage Hereafter In Transit Plant	Almont WWTF	COG588012
COGUUGOSa	East River Regional Sanitation District	East River Regional SD WWTF	COG588079
COGUUGOSb	Crested Butte South Metro District	Crested Butte South Metro Dist WWTF	COG588045
COGUUG08	Crested Butte Town of	Crested Butte Town of WWTF	CO0020443
C0GUUG13	Mt Crested Butte WSD	Mt Crested Butte WSD	CO0027171
C0GUUG14	Camp Gunnison Inc	Camp Gunnison Church Camp	COG588112
C0GUUG14	Gunnison City of	Gunnison City of	CO0041530
COGUUG29a	Land N Inc	L & N Inc	COG588052
COGUUG29a	Lake City Town of	Lake City WWTF	CO0040673
COGUUG29a	Ute Trail Ranch Foundation	Sky Ranch at Ute Trail	COG588109
COGUNF03	Hotchkiss Town of	Hotchkiss Town of	CO0044903
COGUNF03	Paonia Town of	Paonia WWTF	CO0047431
COGUNF04a,c	Scarp Ridge Lodge	Irwin Mountain Lodge	CO0045217
COGUNF06b	Crawford Town of	Crawford WWTF	CO0037729
COGUUNOSb	Ouray City of	Ouray City of	CO0043397
COGUUNOSc	Ridgway Town of	Ridgway, Town of	COG588047
COGUUN04b	Montrose City of	Montrose WWTP	CO0039624
COGUUN04b	Olathe Town of	Olathe Town of	CO0020907
COGUUN04b	West Montrose Sanitation District	West Montrose Sanitation Dist WWTF	CO0030449
COGUUNlOb	Elk Meadows Estates	Elk Meadows WWTF	COG589091
COGULG02	Delta City of	Delta WWTF	CO0039641
COGULG06b	Delta Correctional Center	Delta Correctional Center	COG588032
COGULG07b	Volunteers of America Care Fac	Horizon Health Care & Retirement Community	CO0042617
COGULG07b	Cedaredge Town of	Cedaredge WWTF	CO0031984
COGUSMOSb	Last Dollar PUD Improvements Assn	Last Dollar WWTF	COG588005
COGUSMOSb	Telluride Town of	Regional WWTF	CO0041840
COGUSM04a	Ilium Park Owners Association	Lawson Hull PUD Ilium Valley WWTF	COG588021
COGUSM04a	Wick Hospitality Group LLC	Blue Jay Restaurant and Lodge	COG588113
COGUSM04a	Fall Creek HOA	Fall Creek	COG588119
COGUSMOSa	Naturita Town of	Naturita WWTF	CO0024007
COGUSM08	Stemz LLC	Ilium Power Station Church Camp	COG588033
C0GUSM12C	Nucia Town of	NucIa WWTF	COG589067
COGULD02	SW Mesa County Rural Public Improvement District	SW Mesa Co Rural Pub Imp Dist WWTF	COG588086

Prior to May 31, 2022:

* For segments located entirely above these facilities, nutrient standards apply to the entire segment.

* For segments with portions downstream of these facilities, nutrient standards only apply above these facilities. A note was added to the total phosphorus and chlorophyll a standards in these segments. The note references the table of qualified facilities at 35.5(4).

* For segments located entirely below these facilities, nutrient standards do not apply.

A note was added to the total phosphorus and chlorophyll a standards in lakes segments as nutrients standards apply only to lakes and reservoirs larger than 25 acres surface area.

5 CCR 1002-35.5

38 CR 01, January 10, 2015, effective 6/30/2015

38 CR 03, February 10, 2015, effective 6/30/2015

39 CR 03, February 10, 2016, effective 3/1/2016

39 CR 03, February 10, 2016, effective 6/30/2016

39 CR 23, December 25, 2016, effective 12/30/2016

40 CR 03, February 10, 2017, effective 6/30/2017

40 CR 17, September 10, 2017, effective 12/31/2017

42 CR 04, February 25, 2019, effective 6/30/2019

43 CR 03, February 10, 2020, effective 6/30/2020

44 CR 05, March 10, 2021, effective 6/30/2021

44 CR 17, September 10, 2021, effective 12/31/2021

45 CR 17, September 10, 2022, effective 9/30/2022

46 CR 10, May 25, 2023, effective 6/14/2023