Montana Impaired Waters and TMDL Information

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Data are also available for these cycles:
2004 2006 2008 2010 2012

For More Information:

Montana Assessment Report
State Water Quality Program

Assessed Waters of Montana by Watershed

Select a watershed from the list:

Search for a waterbody within Montana

Year Attaining	Number of Waters Attaining	Number of Causes of Impairment Addressed
NOTE: Click on the underlined "Number of Waters Attaining" value for a detailed list of those previously 303(d)-listed waters now attaining all applicable water quality standards.
2010	1	1
2011	2	2

Cause of Impairment Group Name	Number of Causes of Impairment Reported
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.
Habitat Alterations	641
Metals (other than Mercury)	450
Flow Alteration(s)	333
Sediment	216
Nutrients	163
Temperature	54
Mercury	50
Turbidity	30
Salinity/Total Dissolved Solids/Chlorides/Sulfates	26
Algal Growth	18
pH/Acidity/Caustic Conditions	15
Pathogens	14
Organic Enrichment/Oxygen Depletion	8
Polychlorinated Biphenyls (PCBs)	6
Noxious Aquatic Plants	6
Other Cause	4
Toxic Organics	3
Ammonia	3
Total Toxics	2
Oil and Grease	1
Radiation	1
Pesticides	1

Total: 2,045 Causes of Impairment

This chart includes TMDLs since October 1, 1995.

Pollutant	Number of TMDLs	Number of Causes of Impairment Addressed
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.
Sediment	203	303
Lead	106	107
Copper	96	98
Cadmium	83	91
Zinc	74	76
Arsenic	73	74
Sedimentation/Siltation	58	61
Iron	55	55
Nitrogen, Total	46	49
Phosphorus, Total	36	40
Phosphorus	30	43
Aluminum	25	25
Temperature	25	31
Nitrogen	21	29
Mercury	20	20
Siltation	19	19
Selenium	13	13
Manganese	12	12
Thermal Modifications	10	10
Suspended Solids	9	9
Total Dissolved Solids (TDS)	9	17
Fecal Coliform	8	8
Cyanide	7	7
Escherichia Coli (E. Coli)	7	7
Fecal	7	9
Nickel	7	7
Antimony	6	6
Nitrite/Nitrate	6	6
Total Residual Chlorine	6	6
Total Suspended Solids (TSS)	6	7
Ammonia	5	5
Chromium, Total	3	3
Salinity	3	4
Silver	3	3
Tin	3	3
pH	3	3
Nitrates	2	2
Polychlorinated Biphenyls (PCBs)	2	2
Salinity/Total Dissolved Solids/Sulfates	2	2
Beryllium	1	1
Biochemical Oxygen Demand (BOD)	1	1
Fluoride	1	1
Nitrate	1	1
Nitrate/Nitrite	1	1
Noxious Aquatic Plants	1	1
Nutrients	1	3
Sulfate	1	1
Sulfates	1	1
Thallium	1	1
Total Toxics	1	1
Turbidity	1	1

Total: 1,121 TMDLs; 1,286 Causes of Impairment Addressed

EPA Fiscal Year starts October 1 and ends September 30.

Fiscal Year	Number of TMDLs	Number of Causes of Impairment Addressed
NOTE: Click on the underlined "Number of TMDLs Completed" value for a detailed list of the TMDLs for the fiscal year.
1997	10	10
1998	32	37
1999	18	33
2001	1	1
2002	16	20
2003	46	49
2004	56	75
2005	67	73
2006	124	127
2007	34	36
2008	88	117
2009	119	122
2010	98	99
2011	98	113
2012	143	200
2013	171	174

Total: 1,121 TMDLs; 1,286 Causes of Impairment Addressed