5 Colo. Code Regs. § 1002-36.6
The numeric standards for various parameters in this regulation and in the tables in Appendix 32 1 were assigned by the Commission after a careful analysis of the data presented on actual stream conditions and on actual and potential water uses. For each parameter listed in the tables in Appendix 32-1, only the most stringent standard is shown. Additional, less stringent standards may apply to protect additional uses and can be found in the tables in Regulation No. 31.
Numeric standards are not assigned for all parameters listed in the tables in Regulation No. 31. If additional numeric standards are found to be needed during future periodic reviews, they can be assigned by following the proper hearing procedures.
Ac | = acute (1-day) |
oC | = degrees Celsius |
Ch | = chronic (30-day) |
CL | = cold lake temperature tier |
CLL | = cold large lake temperature tier |
CS-I | = cold stream temperature tier one |
CS-II | = cold stream temperature tier two |
D.O. | = dissolved oxygen |
DM | = daily maximum temperature |
DUWS | = direct use water supply |
E. coli | = Escherichia coli |
mg/L | = milligrams per liter |
MWAT | = maximum weekly average temperature |
OW | = outstanding waters |
sp | = spawning |
SSE | = site-specific equation |
T | = total recoverable |
t | = total |
tr | = trout |
TVS | = table value standard |
µg/L | = micrograms per liter |
UP | = use-protected |
WS | = water supply |
WS-I | = warm stream temperature tier one |
WS-II | = warm stream temperature tier two |
WS-III | = warm stream temperature tier three |
WL | = warm lake temperature tier |
Iron (chronic) | = WS |
Manganese (chronic) | = WS |
Sulfate (chronic) | = WS |
These abbreviations mean: For all surface waters with an actual water supply use, the less restrictive of the following two options shall apply as numerical standards, as specified in the Basic Standards and Methodologies at 31.16 Table II and III:
Iron = | 300 µg/L (dissolved) |
Manganese = | 50 µg/L (dissolved) |
Sulfate = | 250 mg/L (dissolved) |
For all surface waters with a "water supply" classification that are not in actual use as a water supply, no water supply standards are applied for iron, manganese or sulfate, unless the Commission determines as the result of a site-specific rulemaking hearing that such standards are appropriate.
In certain instances in the tables in Appendix 32-1, the designation "TVS" is used to indicate that for a particular parameter a "table value standard" has been adopted. This designation refers to numerical criteria set forth in the Basic Standards and Methodologies for Surface Water. The criteria for which the TVS are applicable are on the following table.
TABLE VALUE STANDARDS
(Concentrations in |jg/L unless noted)
TABLE VALUE STANDARDS - FOOTNOTES
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The following criteria shall be used when assessing whether a specified waterbody is in attainment of the specified standard.
5/1-6/30 Near Surface: | 7/1-4/30 Near Surface: |
Aluminum(chronic)=873(T) µg/L | Aluminum(chronic)=102(T) µg/L |
Aluminum(acute)=TVS(T) µg/L | Aluminum(acute)=TVS(T) µg/L |
Aluminum(chronic)=59 µg/L | Aluminum(chronic)=9 µg/L |
Aluminum(acute)=159 µg/L | Aluminum(acute)=15 µg/L |
5/1-6/30 Near Bottom: | 7/1-4/30 Near Bottom: |
Aluminum(chronic)=1,542(T) µg/L | Aluminum(chronic)=227(T) µg/L |
Aluminum(acute)=5,583(T) µg/L | Aluminum(acute)= TVS(T) µg/L |
Aluminum(chronic)=41 µg/L | Aluminum(chronic)=9 µg/L |
Aluminum(acute)=65 µg/L | Aluminum(acute)=12 µg/L |
Standards effective through 12/31/2028
Low flow (August 1-March 31): Cadmium(chronic)=0.50 µg/L Zinc(acute/chronic)=257 / 164 µg/L | High flow (April 1-July 31): Cadmium(chronic)=0.42 µg/L Zinc(acute/chronic)=115 / 88 µg/L |
Tier 1 standards effective 1/1/2029 through 12/31/2030
Low flow (August 1-March 31): Cadmium(chronic)=TVS Zinc(acute/chronic)=253 / 162 µg/L | High flow (April 1-July 31): Cadmium(chronic)=0.42 µg/L Zinc(acute/chronic)=115 / 88 µg/L |
Tier 2 standards effective from 1/1/2031
Low flow (August 1-March 31): Cadmium(chronic)=TVS Zinc(acute/chronic)=142 / 64 µg/L | High flow (April 1-July 31): Cadmium(chronic)=TVS Zinc(acute/chronic)=51 µg/L / TVS |
Assessment Locations: For assessing the standards on Segment 4a, data from the following three locations will be combined:
* Station RG-4 (a/k/a 8104K): Rio Grande downstream of Highway 149 bridge near Wason Ranch (37.821943, -106.889589)
* Station RG-8 (a/k/a 8104E): Rio Grande upstream of Highway 149 bridge near La Garita Ranch Drive (37.777672, -106.836631)
* Station RG-9 (a/k/a 000135): Rio Grande downstream of 4 UR/Goose Creek Road bridge (37.765798, -106.830305)
Standards effective through 12/31/ 2028
West Willow
Low flow (August 1-March 31): Cadmium(acute/chronic)=32.6 / 27.4 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=108 / 102 µg/L Manganese(acute/chronic)=3,320 / 2,425 µg/L Zinc(acute/chronic)=11,960 / 9,360 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=22.5 / 15.5 µg/L Copper(acute/chronic)=34.3 / 28.0 µg/L Lead(acute/chronic)=TVS / 23.5 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=4,001 / 3,765 µg/L |
Windy Gulch
Low flow (August 1-March 31): Cadmium(acute/chronic)=13.3 / 13.3 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / TVS Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=3,584 / 3,492 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=7.1 / 5.9 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 1.68 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=1,940 / 1,558 µg/L |
Willow Creek
Low flow (August 1-March 31): Cadmium(acute/chronic)=20.9 / 16.9 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 24.4 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=5,861 / 5,427 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=10.9 / 8.5 µg/L Copper(acute/chronic)=11.2 / 8.2 µg/L Lead(acute/chronic)=TVS / 14.2 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=2,667 / 1,873 µg/L |
Tier 1 standards effective 1/1/2029 through 12/31/2030
West Willow
Low flow (August 1-March 31): Cadmium(acute/chronic)=32.6 / 27.4 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=108 / 102 µg/L Manganese(acute/chronic)=3,320 / 2,425 µg/L Zinc(acute/chronic)=11,960 / 9,360 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=22.5 / 15.5 µg/L Copper(acute/chronic)=34.3 / 28.0 µg/L Lead(acute/chronic)=TVS / 23.5 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=4,001 / 3,765 µg/L |
Windy Gulch
Low flow (August 1-March 31): Cadmium(acute/chronic)=13.3 / 13.3 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / TVS Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=3,584 / 3,492 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=7.1 / 5.9 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 1.68 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=1,940 / 1,558 µg/L |
Willow Creek
Low flow (August 1-March 31): Cadmium(acute/chronic)=14.4 / 11.6 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 17.0 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=4,041 / 3,743 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=9.5 / 7.4 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 12.5 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=2,324 / 1,635 µg/L |
Tier 2 standards effective from 1/1/2031
West Willow
Low flow (August 1-March 31): Cadmium(acute/chronic)=19.1 / 13.0 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=68.2 / 61.2 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=6,055 / 3,011 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=14.9 / 7.7 µg/L Copper(acute/chronic)=27.0 / 20.5 µg/L Lead(acute/chronic)=TVS / 9.5 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=2,498 / 2,254 µg/L |
Windy Gulch
Low flow (August 1-March 31): Cadmium(acute/chronic)=13.3 / 13.3 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / TVS Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=3,584 / 3,492 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=7.1 / 5.9 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 1.68 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=1,940 / 1,558 µg/L |
Willow Creek
Low flow (August 1-March 31): Cadmium(acute/chronic)=14.9 / 11.1 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 7.7 µg/L Manganese(acute/chronic)=TVS /TVS Zinc(acute/chronic)=3,521 / 3,106 µg/L | High flow (April 1-July 31): Cadmium(acute/chronic)=6.3 / 4.0 µg/L Copper(acute/chronic)=TVS / TVS Lead(acute/chronic)=TVS / 6.0 µg/L Manganese(acute/chronic)=TVS / TVS Zinc(acute/chronic)=1,758 / 974 µg/L |
Assessment Locations: West Willow
* Station WW-A (a/k/a WW-1): West Willow just above East Willow Confluence (37.864431, -106.925529)
Windy Gulch
* Station WNG-A (a/k/a WG-L): Windy Gulch at mouth (37.856498, -106.928140)
Willow Creek
* Station W-C (a/k/a W-Flume and 8105D): Willow Creek at Flume above Creede (37.855873, -106.927282)
* Saguache Creek above Ford Creek (38.163367, -106.290418)
The stream classifications and water quality standards tables in Appendix 36-1 are incorporated herein by reference.
The following is information regarding duration and measured form of standards in Appendix 36-1:
Discharger-Specific Variance, City of Pueblo James R. DiIorio Water Reclamation Facility (CO0026646): Adopted 6/12/2018.
Selenium (acute) = 19.1 ìg/L: narrative; Selenium (chronic) = 14.1 ìg/L: narrative;
Sulfate (chronic) = 329 mg/L: narrative. Expiration date: 12/31/2028.
Narrative alternative effluent limit: During the DSV term, Pueblo will be required to spend $10 million to implement a comprehensive source control, sampling, analysis, and optimization adaptive management program to reduce selenium and sulfate concentrations in the effluent as much as feasible and to ensure that the discharge does not contribute to any lowering of the currently attained ambient water quality. The adaptive management program will include the following elements, in order of priority:
. Lining up to 175,000 ft2 in the sewer collection system in Basins 2 and 3.
. Sealing up to 400 manholes in Basins 2 and 3.
. The amount of sewer lining and manhole sealing may be reduced by:
* Repair of service taps in poor condition;
* Repair of service lines in poor condition; or
* Additional effort where epoxy sealing of manholes is insufficient to control I & I.
. A comprehensive long-term sampling and analysis program to identify source control projects and evaluate the effectiveness of implemented controls.
. Investigation of the contribution from sump pumps.
. Pilot testing to determine the feasibility of treatment optimization to reduce selenium, and implementation of feasible treatment optimization measures.
Selenium (acute) = TVS: no limit; Selenium (chronic) = TVS: 0.37 lbs/day as a 12-month rolling average. Expiration date: 12/31/2026.
Selenium (chronic) = TVS narrative. Effective Date: 12/30/2018; Expiration Date: 12/31/2025
Narrative alternative effluent limit: During the DSV term, Las Animas will implement a Pollutant Minimization Plan, which is expected to result in effluent concentrations between 0.8 - 28.4 µg/L. The following measures are required during the term of the variance to reduce selenium concentrations as much as feasible and to ensure the discharge does not contribute to any lowering of ambient in-stream water quality:
. Monitor selenium concentrations in each municipal water well and use the wells with the lowest selenium concentrations to meet water demand to the maximum extent feasible
. Initiate a water conservation program
. Locate and repair sources of water loss in the water distribution system.
. Maintain the ongoing sanitary sewer collection system replacement program to address groundwater infiltration
. Complete a wetland treatment pilot study by 12/31/2025, if compliance with water quality based effluent limits based upon the underlying standards remains infeasible after implementing the above measures.
5 CCR 1002-36.6