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Colorado Assessment Summary for Reporting Year 2006

	Size of Water
	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
Good Waters	60,053.0	64,818.8
Previously impaired waters       now attaining all uses
Threatened Waters
TMDL completed
TMDL alternative
Non-pollutant impairment
TMDL needed
Impaired Waters	11,031.7	13,911.3
TMDL completed	221.8
TMDL alternative	4.0
Non-pollutant impairment
TMDL needed	10,805.8	13,911.3
New TMDLs completed	257.0	674.7
Remaining TMDLs needed	10,548.8	13,236.6
Total Assessed Waters	71,084.7	78,730.1
Total Waters	107,403.0	164,029.0
Percent of Waters Assessed	66.2	48.0

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Summary of Water Quality Assessments for Each Waterbody Type
for Reporting Year 2006

Colorado Assessed Waters
Summary of Water Quality Attainment for Rivers and Streams
Reporting Year 2006

Description of this table Assessed Status Miles Assessed 71,084.7 Unassessed 36,318.3 Total Miles 107,403.0

Description of this table Attainment Status Miles Good 60,053.0 Threatened .0 Impaired 11,031.7 Total Miles Assessed 71,084.7

Description of this table TMDL Development Status Miles All TMDLs completed 478.8 TMDL alternative 4.0 Non-pollutant impairment .0 TMDL needed 10,548.8 Total Threatened and Impaired 11,031.7

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Colorado Assessed Waters
Designated Use Support for Rivers and Streams
Reporting Year 2006*

* Waters assessed for more than one designated use are included in multiple designated use groups below.

Designated Use	Miles Assessed	Percent Good	Percent Threatened	Percent Impaired	% Good
					% Threatened
					% Impaired
Agriculture	62,175.1	99.9	.0	.1
Aquatic Life Cold Water-Class 1	33,924.9	89.1	.0	10.9
Aquatic Life Cold Water-Class 2	6,580.4	85.8	.0	14.2
Aquatic Life Warm Water-Class 1	1,338.5	55.2	.0	44.8
Aquatic Life Warm Water-Class 2	25,812.7	78.5	.0	21.5
Domestic Water Source	40,034.2	99.9	.0	.1
Recreation Primary Contact	45,215.3	97.6	.0	2.4
Recreation Secondary Contact	17,058.9	99.0	.0	1.0

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Colorado Causes of Impairment
for Threatened and Impaired Rivers and Streams
Reporting Year 2006

Cause of Impairment	Cause of Impairment Group	Miles Threatened or Impaired
Selenium	Metals (other than Mercury)	5,766.4
Sedimentation/Siltation	Sediment	2,610.4
Escherichia Coli (E. Coli)	Pathogens	990.7
Zinc	Metals (other than Mercury)	641.3
Iron	Metals (other than Mercury)	520.6
Temperature, Water	Temperature	490.4
Copper	Metals (other than Mercury)	368.5
Fecal Coliform	Pathogens	277.7
Cadmium	Metals (other than Mercury)	247.5
Lead	Metals (other than Mercury)	197.2
pH	pH/Acidity/Caustic Conditions	166.4
Cause Unknown	Cause Unknown	138.7
Aluminum	Metals (other than Mercury)	91.0
Ammonia, Un-ionized	Ammonia	46.5
Manganese	Metals (other than Mercury)	32.7
BOD, Sediment Load (Sediment Oxygen Demand)	Organic Enrichment/Oxygen Depletion	12.5
Silver	Metals (other than Mercury)	12.0
Dissolved Oxygen Saturation	Organic Enrichment/Oxygen Depletion	10.0

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Colorado Probable Sources of Impairments
for Threatened and Impaired Rivers and Streams
Reporting Year 2006

Probable Source	Probable Source Group	Miles Threatened or Impaired
Source Unknown	Unknown	7,419.8
Impacts From Abandoned Mine Lands (Inactive)	Resource Extraction	588.5
Natural Sources	Natural/Wildlife	184.5
Flow Alterations From Water Diversions	Hydromodification	163.3
Contaminated Groundwater	Groundwater Loadings/Withdrawals	26.7
Highway/Road/Bridge Runoff (Non-Construction Related)	Urban-Related Runoff/Stormwater	16.8

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Colorado Assessed Waters
Summary of Water Quality Attainment for Lakes, Reservoirs, and Ponds
Reporting Year 2006

Description of this table Assessed Status Acres Assessed 78,730.1 Unassessed 85,298.9 Total Acres 164,029.0

Description of this table Attainment Status Acres Good 64,818.8 Threatened .0 Impaired 13,911.3 Total Acres Assessed 78,730.1

Description of this table TMDL Development Status Acres All TMDLs completed 674.7 TMDL alternative .0 Non-pollutant impairment .0 TMDL needed 13,236.6 Total Threatened and Impaired 13,911.3

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Colorado Assessed Waters
Designated Use Support for Lakes, Reservoirs, and Ponds
Reporting Year 2006*

* Waters assessed for more than one designated use are included in multiple designated use groups below.

Designated Use	Acres Assessed	Percent Good	Percent Threatened	Percent Impaired	% Good
					% Threatened
					% Impaired
Agriculture	70,162.6	100.0	.0	.0
Aquatic Life Cold Water-Class 1	45,899.2	82.4	.0	17.6
Aquatic Life Cold Water-Class 2	142.0	.0	.0	100.0
Aquatic Life Warm Water-Class 1	19,002.4	93.6	.0	6.4
Aquatic Life Warm Water-Class 2	4,781.9	6.2	.0	93.8
Domestic Water Source	55,549.7	100.0	.0	.0
Recreation Primary Contact	55,725.8	100.0	.0	.0
Recreation Secondary Contact	2,449.5	100.0	.0	.0

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Colorado Causes of Impairment
for Threatened and Impaired Lakes, Reservoirs, and Ponds
Reporting Year 2006

Cause of Impairment	Cause of Impairment Group	Acres Threatened or Impaired
Mercury in Fish Tissue	Mercury	5,819.0
pH	pH/Acidity/Caustic Conditions	3,834.9
Dissolved Oxygen	Organic Enrichment/Oxygen Depletion	1,807.1
Dissolved Oxygen Saturation	Organic Enrichment/Oxygen Depletion	1,006.5
Chlorophyll-A	Algal Growth	916.2
Ammonia, Un-ionized	Ammonia	530.5
Iron	Metals (other than Mercury)	530.5
Selenium	Metals (other than Mercury)	285.6
Copper	Metals (other than Mercury)	142.0
Tetrachloroethylene	Toxic Organics	78.4
Arsenic	Metals (other than Mercury)	21.7

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Colorado Probable Sources of Impairments
for Threatened and Impaired Lakes, Reservoirs, and Ponds
Reporting Year 2006

Probable Source	Probable Source Group	Acres Threatened or Impaired
Source Unknown	Unknown	7,142.8
Impacts From Abandoned Mine Lands (Inactive)	Resource Extraction	142.0
Contaminated Groundwater	Groundwater Loadings/Withdrawals	78.4

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Colorado Causes of Impairment for Reporting Year 2006

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Colorado Probable Sources Contributing to Impairments
for Reporting Year 2006

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Colorado TMDL Alternatives by Cause of Impairment 2006

NOTE: Click on the underlined "Number of TMDL Alternatives by Cause of Impairment " value to see a listing of those Causes of Impairment.
Cause of Impairment	Number of TMDL Alternatives	Rivers and Streams (Miles)
Selenium	3	60
Copper	2	4
Cadmium	1	3
Zinc	1	3

Total: 7 TMDL Alternatives

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Colorado Previously Impaired Waters Now Attaining All Uses

NOTE: Click on the underlined "Number of Waters Attaining" value for a detailed list of those waters now attaining all uses.
Cycle Attaining	Number of Waters Attaining	Number of Causes of Impairment Addressed
2008	7	8

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Colorado Causes of Impairment for 303(d) Listed Waters

NOTE: Click on a cause of impairment (e.g. pathogens) to see the specific state-reported causes that are grouped to make up this category. Click on the "Number of Causes of Impairment Reported" to see a list of waters with that cause of impairment.
Cause of Impairment Group Name	Number of Causes of Impairment Reported
Metals (other than Mercury)	167
Pathogens	19
pH/Acidity/Caustic Conditions	9
Organic Enrichment/Oxygen Depletion	6
Sediment	5
Mercury	4
Ammonia	2
Algal Growth	1
Cause Unknown - Impaired Biota	1
Temperature	1
Toxic Organics	1

Total: 216 Causes of Impairment

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Colorado Cumulative TMDLs by Pollutant

This chart includes TMDLs since October 1, 1995.

NOTE: Click on the underlined "Pollutant" value to see associated listed waters for which a TMDL was developed. Click on the underlined "Number of TMDLs" value to see a listing of those TMDLs for the pollutant.
Pollutant	Number of TMDLs	Number of Causes of Impairment Addressed
Ammonia	128	129
Fecal Coliform	126	126
Total Residual Chlorine	99	101
Zinc	69	72
Copper	68	68
Chlorine	45	45
Cadmium	42	44
Ammonia, Un-ionized	41	41
Lead	39	39
Iron	38	38
Mercury	27	27
Silver	26	26
Escherichia Coli (E. Coli)	22	22
Manganese	21	21
Fecal	20	20
Cyanide	17	17
Selenium	17	17
Chlorine, Residual (Chlorine Demand)	14	14
Aluminum	8	9
Boron	8	8
Chromium VI	8	8
Arsenic	7	7
Phosphorus	6	8
Sediment	5	5
Chloride	4	4
Chromium	4	4
Chromium III	4	4
pH	4	4
Dissolved Oxygen	3	3
Nickel	3	3
Sulfide	3	3
Total Inorganic Nitrogen	3	3
Uranium	3	3
Benzene	2	2
MTBE	2	2
Nitrate	2	2
Radium	2	2
1,2-Dichloroethane	1	1
Antimony	1	1
Benzo[a]pyrene	1	1
Beryllium	1	1
Chromium IV	1	1
Contaminated Sediments (Copper)	1	1
Contaminated Sediments (Nickel)	1	1
Fluoride	1	1
Mercury in Fish Tissue	1	1
Nitrogen	1	1
Other Toxic Organics	1	1
Sulfate	1	1
Tetrachloroethene	1	1
Thallium	1	1
Trichloroethene	1	1

Total: 955 TMDLs; 966 Causes of Impairment Addressed

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Colorado Cumulative Number of TMDLs

EPA Fiscal Year starts October 1 and ends September 30.

NOTE: Click on the underlined "Number of TMDLs Completed" value for a detailed list of the TMDLs for the fiscal year.
Fiscal Year	Number of TMDLs	Number of Causes of Impairment Addressed
1997	94	96
1998	23	23
1999	42	42
2000	36	36
2001	40	40
2002	137	139
2003	50	50
2004	153	154
2005	166	166
2006	75	75
2007	70	71
2008	42	45
2009	27	29

Total: 955 TMDLs; 966 Causes of Impairment Addressed

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TMDL Document Search

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