Montana Water Quality Assessment Report

Assessed Waters of Montana by Watershed

Select a watershed from the list:
or click on the map to choose a watershed:

Search for a waterbody within Montana

Features

Site-specific Targeted Monitoring Summary Results

Montana (2010)

	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
	Size of Water
Good Waters	3,008.2	69,517.5
Previously impaired waters now attaining all uses	144.9
Threatened Waters		6,036.7
TMDL completed		2,680.0
TMDL alternative
Non-pollutant impairment		6.8
TMDL needed		3,349.9
Impaired Waters	17,234.2	461,096.4
TMDL completed	2,081.2	1,900.0
TMDL alternative
Non-pollutant impairment	1,849.4	8,998.4
TMDL needed	13,303.6	450,198.1
New TMDLs completed	556.8	20.0
Remaining TMDLs needed	12,746.8	450,178.1

Total Assessed Waters	20,242.4	536,650.7
Total Waters	176,750.0	844,802.0
Percent of Waters Assessed	11.5	63.5

Top of page

Summary of Water Quality Assessments for Each Waterbody Type
for Reporting Year 2010

Site-specific Targeted Monitoring Results

Montana Rivers and Streams 2010

Description of this table

Assessed Status	Miles

Assessed	20,242.4
Unassessed	156,507.6
Total Miles	176,750.0

Description of this table

Attainment Status	Miles

Good	3,008.2
Threatened	.0
Impaired	17,234.2
Total Miles Assessed	20,242.4

Description of this table

TMDL Development Status	Miles

All TMDLs completed	2,638.0
TMDL alternative	.0
Non-pollutant impairment	1,849.4
TMDL needed	12,746.8
Total Threatened and Impaired	17,234.2

Top of page

Site-specific Targeted Monitoring Results

Individual Designated Use Support
Montana Rivers and Streams 2010

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

Description of this table

Designated Use	Miles Assessed	Percent Good	Percent Threatened	Percent Impaired	% Good
					% Threatened
					% Impaired
Agricultural	14,303.3	84.3	.0	15.7
Aquatic Life	18,751.2	18.1	.0	81.9
Cold Water Fishes	10,946.4	15.8	.0	84.2
Drinking Water	12,141.1	69.7	.0	30.3
Industrial	13,661.1	89.0	.0	11.0
Primary Contact Recreation	15,783.7	60.9	.9	38.3
Warm Water Fishes	7,295.8	16.8	.0	83.2

Top of page

Site-specific Targeted Monitoring Results

Causes of Impairment
Montana Rivers and Streams 2010

Description of this table

Cause of Impairment	Cause of Impairment Group	Miles Threatened or Impaired
Alteration in Stream-Side or Littoral Vegetative Covers	Habitat Alterations	8,325.1
Sedimentation/Siltation	Sediment	7,300.8
Low Flow Alterations	Flow Alteration(s)	4,987.9
Phosphorus, Total	Nutrients	4,894.6
Physical Substrate Habitat Alterations	Habitat Alterations	3,511.1
Lead	Metals (other than Mercury)	3,344.8
Copper	Metals (other than Mercury)	3,121.0
Total Kjehldahl Nitrogen (TKN)	Nutrients	2,911.5
Temperature, Water	Temperature	2,687.7
Nitrate/Nitrite (Nitrite + Nitrate as N)	Nutrients	2,239.6
Iron	Metals (other than Mercury)	2,195.8
Nitrogen, Total	Nutrients	2,018.3
Mercury	Mercury	1,888.8
Salinity	Salinity/Total Dissolved Solids/Chlorides/Sulfates	1,698.8
Zinc	Metals (other than Mercury)	1,693.2
Cadmium	Metals (other than Mercury)	1,654.1
Chlorophyll-A	Algal Growth	1,550.8
Arsenic	Metals (other than Mercury)	1,504.7
Other Flow Regime Alterations	Flow Alteration(s)	1,402.5
Solids (Suspended/Bedload)	Sediment	1,388.6
Total Dissolved Solids (TDS)	Salinity/Total Dissolved Solids/Chlorides/Sulfates	1,272.5
Sulfates	Salinity/Total Dissolved Solids/Chlorides/Sulfates	703.2
Fish Passage Barrier	Habitat Alterations	521.6
Dissolved Oxygen	Organic Enrichment/Oxygen Depletion	494.2
Specific Conductivity	Salinity/Total Dissolved Solids/Chlorides/Sulfates	473.3
Fecal Coliform	Pathogens	439.5
Other Anthropogenic Substrate Alterations	Habitat Alterations	396.3
Excess Algal Growth	Algal Growth	360.6
pH	pH/Acidity/Caustic Conditions	352.8
Selenium	Metals (other than Mercury)	340.6
Chromium, Total	Metals (other than Mercury)	308.9
Nitrogen, Nitrate	Nutrients	307.3
Aluminum	Metals (other than Mercury)	283.1
Nitrates	Nutrients	269.6
Ammonia, Un-ionized	Ammonia	221.6
Cause Unknown	Cause Unknown	217.1
Nickel	Metals (other than Mercury)	203.9
Organic Enrichment (Sewage) Biological Indicators	Organic Enrichment/Oxygen Depletion	186.9
Turbidity	Turbidity	168.6
High Flow Regime	Flow Alteration(s)	160.7
Manganese	Metals (other than Mercury)	153.0
Silver	Metals (other than Mercury)	147.0
Total Suspended Solids (TSS)	Turbidity	125.3
Other Cause	Other Cause	111.6
Cyanide	Toxic Inorganics	91.5
Uranium	Radiation	86.9
Benthic Macroinvertebrates Bioassessments	Cause Unknown - Impaired Biota	84.8
Escherichia Coli (E. Coli)	Pathogens	84.2
Antimony	Toxic Inorganics	78.1
Sodium	Salinity/Total Dissolved Solids/Chlorides/Sulfates	75.7
Ammonia, Total	Ammonia	68.6
Biochemical Oxygen Demand (BOD)	Organic Enrichment/Oxygen Depletion	64.2
Alterations in Wetland Habitats	Habitat Alterations	46.9
Nutrient/Eutrophication Biological Indicators	Nutrients	37.2
Polychlorinated Biphenyls (PCBs)	Polychlorinated Biphenyls (PCBs)	31.1
Bottom Deposits	Sediment	30.6
PCB in Water Column	Polychlorinated Biphenyls (PCBs)	24.8
Oil and Grease	Oil and Grease	24.8
Polycyclic Aromatic Hydrocarbons (PAHs) (Aquatic Ecosystems)	Toxic Organics	21.8
DDE	Pesticides	20.4
Dissolved Gas Supersaturation	Other Cause	18.9
Chloride	Salinity/Total Dissolved Solids/Chlorides/Sulfates	17.6
Mercury in Water Column	Mercury	17.6
PCB-1254	Polychlorinated Biphenyls (PCBs)	16.1
PCB-1260	Polychlorinated Biphenyls (PCBs)	16.1
Combined Biota/Habitat Bioassessments (Streams)	Cause Unknown - Impaired Biota	13.4
Aquatic Plants - Native	Nuisance Native Species	13.0
Barium	Radiation	12.0
Cobalt	Metals (other than Mercury)	12.0
Non-Native Fish/Shellfish/Zooplankton	Nuisance Exotic Species	11.0
Periphyton (Aufwuchs) Indicator Bioassessments (Streams)	Cause Unknown - Impaired Biota	10.7
Dissolved Oxygen Saturation	Organic Enrichment/Oxygen Depletion	10.7
Thallium	Metals (other than Mercury)	7.9
Beryllium	Metals (other than Mercury)	5.4

Top of page

Site-specific Targeted Monitoring Results

Probable Sources
Montana Rivers and Streams 2010

Description of this table

Probable Source	Probable Source Group	Miles Threatened or Impaired
Agriculture	Agriculture	5,643.8
Grazing In Riparian Or Shoreline Zones	Agriculture	5,623.4
Source Unknown	Unknown	4,651.5
Irrigated Crop Production	Agriculture	4,545.8
Natural Sources	Natural/Wildlife	4,471.6
Streambank Modifications/Destabilization	Hydromodification	2,573.9
Impacts From Hydrostructure Flow Regulation/Modification	Hydromodification	2,329.3
Rangeland Grazing	Agriculture	2,190.4
Channelization	Hydromodification	1,974.2
Impacts From Abandoned Mine Lands (Inactive)	Resource Extraction	1,973.1
Loss Of Riparian Habitat	Habitat Alterations (Not Directly Related To Hydromodification)	1,859.9
Flow Alterations From Water Diversions	Hydromodification	1,443.9
Dam Or Impoundment	Hydromodification	1,350.7
Highways, Roads, Bridges, Infrastructure (New Construction)	Construction	1,175.2
Forest Roads (Road Construction And Use)	Silviculture (Forestry)	1,006.4
Silviculture Activities	Silviculture (Forestry)	897.3
Municipal Point Source Discharges	Municipal Discharges/Sewage	749.9
Acid Mine Drainage	Resource Extraction	683.4
Crop Production (Crop Land Or Dry Land)	Agriculture	679.7
Non-Irrigated Crop Production	Agriculture	678.7
Highway/Road/Bridge Runoff (Non-Construction Related)	Urban-Related Runoff/Stormwater	671.5
Unspecified Unpaved Road Or Trail	Urban-Related Runoff/Stormwater	585.2
Site Clearance (Land Development Or Redevelopment)	Construction	579.1
Dam Construction (Other Than Upstream Flood Control Projects)	Hydromodification	539.1
Mine Tailings	Resource Extraction	524.2
Silviculture Harvesting	Silviculture (Forestry)	505.7
Habitat Modification - Other Than Hydromodification	Habitat Alterations (Not Directly Related To Hydromodification)	485.6
Animal Feeding Operations (Nps)	Agriculture	447.1
Mill Tailings	Industrial	407.6
Contaminated Sediments	Legacy/Historical Pollutants	294.3
Placer Mining	Resource Extraction	275.4
Subsurface (Hardrock) Mining	Resource Extraction	258.2
Industrial Point Source Discharge	Industrial	234.7
Transfer Of Water From An Outside Watershed	Hydromodification	182.8
Dredge Mining	Resource Extraction	143.4
Hydrostructure Impacts On Fish Passage	Hydromodification	140.4
Drought-Related Impacts	Natural/Wildlife	133.8
Livestock (Grazing Or Feeding Operations)	Agriculture	130.3
Surface Mining	Resource Extraction	119.6
Above Ground Storage Tank Leaks (Tank Farms)	Spills/Dumping	117.3
Post-Development Erosion And Sedimentation	Hydromodification	116.7
Residential Districts	Urban-Related Runoff/Stormwater	115.3
Managed Pasture Grazing	Agriculture	107.3
Watershed Runoff Following Forest Fire	Silviculture (Forestry)	101.5
Impacts From Resort Areas (Winter And Non-Winter Resorts)	Recreation And Tourism (Non-Boating)	97.4
Golf Courses	Recreation And Tourism (Non-Boating)	96.8
On-Site Treatment Systems (Septic Systems And Similar Decentralized Systems)	Municipal Discharges/Sewage	96.2
Wet Weather Discharges (Point Source And Combination Of Stormwater, Sso Or Cso)	Municipal Discharges/Sewage	82.7
Upstream Impoundments (E.G., Pl-566 Nrcs Structures)	Hydromodification	77.3
Upstream Source	Other	76.3
Coal Mining	Resource Extraction	66.5
Permitted Runoff From Confined Animal Feeding Operations (Cafos)	Agriculture	64.2
Atmospheric Deposition - Nitrogen	Atmospheric Deposition	62.9
Channel Erosion/Incision From Upstream Hydromodifications	Hydromodification	55.3
Low Water Crossing	Other	51.6
Aquaculture (Permitted)	Aquaculture	51.4
Hardrock Mining Discharges (Permitted)	Resource Extraction	45.6
Crop Production With Subsurface Drainage	Agriculture	45.3
Yard Maintenance	Urban-Related Runoff/Stormwater	37.7
Atmospheric Deposition - Toxics	Atmospheric Deposition	32.7
Sediment Resuspension (Clean Sediment)	Hydromodification	28.9
Spills From Trucks Or Trains	Spills/Dumping	27.5
Unspecified Urban Stormwater	Urban-Related Runoff/Stormwater	24.9
Sediment Resuspension (Contaminated Sediment)	Hydromodification	23.6
Other Recreational Pollution Sources	Recreation And Tourism (Non-Boating)	22.6
Petroleum/Natural Gas Production Activities (Permitted)	Industrial	21.8
Pipeline Breaks	Spills/Dumping	21.8
Wet Weather Discharges (Non-Point Source)	Urban-Related Runoff/Stormwater	15.0
Construction Stormwater Discharge (Permitted)	Construction	14.3
Discharges From Municipal Separate Storm Sewer Systems (Ms4)	Urban-Related Runoff/Stormwater	13.2
Freshettes Or Major Flooding	Natural/Wildlife	11.6
Open Pit Mining	Resource Extraction	10.3
Septage Disposal	Municipal Discharges/Sewage	9.8
Municipal (Urbanized High Density Area)	Urban-Related Runoff/Stormwater	7.3
Industrial/Commercial Site Stormwater Discharge (Permitted)	Urban-Related Runoff/Stormwater	7.0
Baseflow Depletion From Groundwater Withdrawals	Hydromodification	4.8
Heap-Leach Extraction Mining	Resource Extraction	3.8
Erosion From Derelict Land (Barren Land)	Hydromodification	3.1
Sources Outside State Jurisdiction Or Borders	Other	2.9

Top of page

Site-specific Targeted Monitoring Results

Montana Lakes, Reservoirs, and Ponds 2010

Description of this table

Assessed Status	Acres

Assessed	536,650.7
Unassessed	308,151.3
Total Acres	844,802.0

Description of this table

Attainment Status	Acres

Good	69,517.5
Threatened	6,036.7
Impaired	461,096.4
Total Acres Assessed	536,650.7

Description of this table

TMDL Development Status	Acres

All TMDLs completed	4,600.0
TMDL alternative	.0
Non-pollutant impairment	9,005.2
TMDL needed	453,528.0
Total Threatened and Impaired	467,133.2

Top of page

Site-specific Targeted Monitoring Results

Individual Designated Use Support
Montana Lakes, Reservoirs, and Ponds 2010

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

Description of this table

Designated Use	Acres Assessed	Percent Good	Percent Threatened	Percent Impaired	% Good
					% Threatened
					% Impaired
Agricultural	263,282.3	80.5	.0	19.5
Aquatic Life	291,347.7	36.5	2.1	61.4
Cold Water Fishes	257,203.7	87.5	2.3	10.1
Drinking Water	491,702.8	38.7	.0	61.3
Industrial	266,917.2	97.1	.0	2.9
Primary Contact Recreation	520,022.4	40.8	.0	59.2
Warm Water Fishes	26,500.7	16.3	.0	83.7

Top of page

Site-specific Targeted Monitoring Results

Causes of Impairment
Montana Lakes, Reservoirs, and Ponds 2010

Description of this table

Cause of Impairment	Cause of Impairment Group	Acres Threatened or Impaired
Mercury	Mercury	387,377.8
Lead	Metals (other than Mercury)	257,122.0
Aquatic Plants - Native	Nuisance Native Species	248,500.0
Phosphorus, Total	Nutrients	138,350.5
Nitrogen, Total	Nutrients	132,484.0
Sedimentation/Siltation	Sediment	132,230.8
Polychlorinated Biphenyls (PCBs)	Polychlorinated Biphenyls (PCBs)	125,601.3
Excess Algal Growth	Algal Growth	38,409.9
Arsenic	Metals (other than Mercury)	34,450.9
Thallium	Metals (other than Mercury)	32,809.9
Ammonia, Un-ionized	Ammonia	32,809.9
Other Flow Regime Alterations	Flow Alteration(s)	16,253.2
Salinity	Salinity/Total Dissolved Solids/Chlorides/Sulfates	13,024.3
Selenium	Metals (other than Mercury)	12,902.3
Sulfates	Salinity/Total Dissolved Solids/Chlorides/Sulfates	9,400.0
Cadmium	Metals (other than Mercury)	8,883.8
Physical Substrate Habitat Alterations	Habitat Alterations	7,780.8
Dissolved Oxygen	Organic Enrichment/Oxygen Depletion	7,652.6
Total Dissolved Solids (TDS)	Salinity/Total Dissolved Solids/Chlorides/Sulfates	3,800.0
Endosulfan Sulfate	Pesticides	3,800.0
Nitrogen, Nitrate	Nutrients	3,800.0
Endrin Aldehyde	Pesticides	3,800.0
DDT	Pesticides	3,800.0
Other Anthropogenic Substrate Alterations	Habitat Alterations	3,783.1
Cause Unknown	Cause Unknown	3,780.8
Chromium, Total	Metals (other than Mercury)	3,780.8
Low Flow Alterations	Flow Alteration(s)	3,780.8
Solids (Suspended/Bedload)	Sediment	3,764.8
Chlorophyll-A	Algal Growth	3,506.8
BOD, Sediment Load (Sediment Oxygen Demand)	Organic Enrichment/Oxygen Depletion	2,680.0
Copper	Metals (other than Mercury)	1,923.0
Iron	Metals (other than Mercury)	1,903.0
Total Kjehldahl Nitrogen (TKN)	Nutrients	617.4
Alteration in Stream-Side or Littoral Vegetative Covers	Habitat Alterations	285.8
Other Cause	Other Cause	80.0
pH	pH/Acidity/Caustic Conditions	20.0
Zinc	Metals (other than Mercury)	20.0

Top of page

Site-specific Targeted Monitoring Results

Probable Sources
Montana Lakes, Reservoirs, and Ponds 2010

Description of this table

Probable Source	Probable Source Group	Acres Threatened or Impaired
Agriculture	Agriculture	301,550.9
Impacts From Abandoned Mine Lands (Inactive)	Resource Extraction	287,833.0
Atmospheric Deposition - Toxics	Atmospheric Deposition	257,956.4
Historic Bottom Deposits (Not Sediment)	Legacy/Historical Pollutants	249,357.4
Municipal Point Source Discharges	Municipal Discharges/Sewage	163,961.3
Source Unknown	Unknown	151,894.2
Impacts From Hydrostructure Flow Regulation/Modification	Hydromodification	139,633.9
Silviculture Harvesting	Silviculture (Forestry)	122,251.4
Atmospheric Deposition - Nitrogen	Atmospheric Deposition	122,251.4
Unspecified Urban Stormwater	Urban-Related Runoff/Stormwater	122,251.4
Upstream Impoundments (E.G., Pl-566 Nrcs Structures)	Hydromodification	122,251.4
Natural Sources	Natural/Wildlife	43,893.7
Acid Mine Drainage	Resource Extraction	38,190.7
On-Site Treatment Systems (Septic Systems And Similar Decentralized Systems)	Municipal Discharges/Sewage	36,609.9
Internal Nutrient Recycling	Natural/Wildlife	32,809.9
Site Clearance (Land Development Or Redevelopment)	Construction	32,809.9
Irrigated Crop Production	Agriculture	26,789.7
Grazing In Riparian Or Shoreline Zones	Agriculture	7,403.7
Silviculture Activities	Silviculture (Forestry)	7,156.7
Forest Roads (Road Construction And Use)	Silviculture (Forestry)	6,029.9
Rangeland Grazing	Agriculture	4,932.1
Drought-Related Impacts	Natural/Wildlife	4,888.0
Placer Mining	Resource Extraction	4,357.4
Inappropriate Waste Disposal	Spills/Dumping	4,357.4
Dam Construction (Other Than Upstream Flood Control Projects)	Hydromodification	3,800.0
Highway/Road/Bridge Runoff (Non-Construction Related)	Urban-Related Runoff/Stormwater	3,800.0
Habitat Modification - Other Than Hydromodification	Habitat Alterations (Not Directly Related To Hydromodification)	3,780.8
Dam Or Impoundment	Hydromodification	3,610.4
Upstream Source	Other	3,332.1
Highways, Roads, Bridges, Infrastructure (New Construction)	Construction	2,703.3
Low Water Crossing	Other	1,126.0
Upstream/Downstream Source	Other	352.6
Transfer Of Water From An Outside Watershed	Hydromodification	264.8
Petroleum/Natural Gas Activities	Resource Extraction	21.0
Non-Irrigated Crop Production	Agriculture	2.3

Top of page

Montana Causes of Impairment for Reporting Year 2010

Description of this table

Cause of Impairment Group	Size of Assessed Waters with Listed Causes of Impairment
NOTE: Click on the underlined Cause of Impairment Group to see a list of specific state causes of impairment making up the Cause of Impairment Group. See also Pollution categories summary document (PDF) (20 pp, 557K, About PDF) for brief, non-technical descriptions of general cause categories.
Cause of Impairment Group	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
Algal Growth	1,898.3	41,916.8
Ammonia	290.2	32,809.9
Cause Unknown	217.1	3,780.8
Cause Unknown - Impaired Biota	98.3
Flow Alteration(s)	6,529.8	20,034.0
Habitat Alterations	9,852.4	8,068.9
Mercury	1,906.4	387,377.8
Metals (other than Mercury)	5,561.6	306,900.8
Nuisance Exotic Species	11.0
Nuisance Native Species	13.0	248,500.0
Nutrients	7,085.2	143,950.5
Oil and Grease	24.8
Organic Enrichment/Oxygen Depletion	756.1	10,332.6
Other Cause	130.4	80.0
Pathogens	523.7
Pesticides	20.4	3,800.0
pH/Acidity/Caustic Conditions	352.8	20.0
Polychlorinated Biphenyls (PCBs)	72.1	125,601.3
Radiation	98.8
Salinity/Total Dissolved Solids/Chlorides/Sulfates	2,836.2	16,524.3
Sediment	8,259.7	135,730.8
Temperature	2,687.7
Toxic Inorganics	165.9
Toxic Organics	21.8
Turbidity	293.9

Top of page

Montana Probable Sources Contributing to Impairments
for Reporting Year 2010

Description of this table

Probable Source Group	Size of Assessed Waters with Probable Sources of Impairments
NOTE: Click on the underlined Probable Source Group to see a list of specific state Probable Sources making up the Probable Source Group.
Probable Source Group	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
Agriculture	12,352.9	315,707.7
Aquaculture	51.4
Atmospheric Deposition	95.6	380,207.9
Construction	1,624.9	35,513.2
Habitat Alterations (Not Directly Related To Hydromodification)	2,233.2	3,780.8
Hydromodification	7,235.1	143,509.1
Industrial	605.2
Legacy/Historical Pollutants	294.3	249,357.4
Municipal Discharges/Sewage	904.5	163,961.3
Natural/Wildlife	4,617.1	48,781.7
Other	127.9	3,684.7
Recreation And Tourism (Non-Boating)	216.7
Resource Extraction	2,698.5	287,854.0
Silviculture (Forestry)	1,921.1	132,088.2
Spills/Dumping	166.5	4,357.4
Unknown	4,651.5	151,894.2
Urban-Related Runoff/Stormwater	1,439.9	126,051.4

Top of page

Montana TMDL Alternatives by Cause of Impairment 2010

No TMDL Alternatives reported.

Top of page

Montana Previously 303(d)-Listed Waters Now Attaining All Applicable Water Quality Standards

Description of this table

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

Top of page

Montana Causes of Impairment for 303(d) Listed Waters

Description of this table

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.
Metals (other than Mercury)	575
Nutrients	460
Sediment	254
Mercury	75
Temperature	72
Salinity/Total Dissolved Solids/Chlorides/Sulfates	70
Turbidity	54
Organic Enrichment/Oxygen Depletion	20
pH/Acidity/Caustic Conditions	19
Habitat Alterations	19
Pathogens	18
Ammonia	11
Toxic Inorganics	10
Flow Alteration(s)	7
Cause Unknown - Impaired Biota	6
Polychlorinated Biphenyls (PCBs)	3
Pesticides	3
Algal Growth	3
Other Cause	3
Radiation	2
Toxic Organics	1
Nuisance Exotic Species	1
Oil and Grease	1

Total: 1,687 Causes of Impairment

Top of page

Montana Cumulative TMDLs by Pollutant

This chart includes TMDLs since October 1, 1995.

Description of this table

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	105	107
Copper	96	98
Cadmium	83	91
Zinc	73	76
Arsenic	72	74
Sedimentation/Siltation	58	61
Iron	54	55
Nitrogen, Total	45	49
Phosphorus, Total	35	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
Nitrite/Nitrate	6	6
Total Residual Chlorine	6	6
Total Suspended Solids (TSS)	6	7
Ammonia	5	5
Antimony	5	6
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: 1,114 TMDLs; 1,286 Causes of Impairment Addressed

Top of page

Montana Cumulative Number of TMDLs

EPA Fiscal Year starts October 1 and ends September 30.

Description of this table

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	164	174

Total: 1,114 TMDLs; 1,286 Causes of Impairment Addressed

Top of page

TMDL Document Search

Full Text Search of TMDL Documents

Top of page