Recent Additions | Contact Us Search: All EPA This Area

• You are here: EPA Home
• Water
• WATERS
• Water Quality Assessment and TMDL Information
• Wyoming Water Quality Assessment Report

---

Wyoming Assessment Summary for Reporting Year 2008

Description of this table

	Size of Water
	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
Good Waters	5,920.5	418.0
Previously impaired waters       now attaining all uses
Threatened Waters	262.0
TMDL completed
TMDL alternative
Non-pollutant impairment
TMDL needed	262.0
Impaired Waters	1,175.4	6,237.6
TMDL completed	6.5
TMDL alternative
Non-pollutant impairment	26.5
TMDL needed	1,142.3	6,237.6
New TMDLs completed	.0	.0
Remaining TMDLs needed	1,142.3	6,237.6
Total Assessed Waters	7,357.9	6,655.6
Total Waters	108,767.0	325,048.0
Percent of Waters Assessed	6.8	2.0

Top of page

---

Summary of Water Quality Assessments for Each Waterbody Type
for Reporting Year 2008

Wyoming Assessed Waters
Summary of Water Quality Attainment for Rivers and Streams
Reporting Year 2008

Description of this table Assessed Status Miles Assessed 7,357.9 Unassessed 101,409.1 Total Miles 108,767.0

Description of this table Attainment Status Miles Good 5,920.5 Threatened 262.0 Impaired 1,175.4 Total Miles Assessed 7,357.9

Description of this table TMDL Development Status Miles All TMDLs completed 6.5 TMDL alternative .0 Non-pollutant impairment 26.5 TMDL needed 1,404.3 Total Threatened and Impaired 1,437.4

Top of page

Wyoming Assessed Waters
Designated Use Support for Rivers and Streams
Reporting Year 2008*

* 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
Aquatic Life Other Than Fish	6,764.5	89.6	2.2	8.2
Cold Water Fishery	5,750.3	93.6	2.3	4.1
Drinking Water	30.8	.0	.0	100.0
Non-Game Fish	115.7	.0	.0	100.0
Recreation	795.9	.2	14.5	85.3
Warm Water Fishery	344.6	48.2	.0	51.8
Wildlife	379.6	10.6	.0	89.4

Top of page

Wyoming Causes of Impairment
for Threatened and Impaired Rivers and Streams
Reporting Year 2008

Description of this table

Cause of Impairment	Cause of Impairment Group	Miles Threatened or Impaired
Fecal Coliform	Pathogens	665.0
Selenium	Metals (other than Mercury)	348.8
Physical Substrate Habitat Alterations	Habitat Alterations	178.4
Escherichia Coli (E. Coli)	Pathogens	125.7
Chloride	Salinity/Total Dissolved Solids/Chlorides/Sulfates	64.8
Sedimentation/Siltation	Sediment	63.9
Ammonia, Un-ionized	Ammonia	45.4
Low Flow Alterations	Flow Alteration(s)	32.2
Manganese	Metals (other than Mercury)	30.8
Oil and Grease	Oil and Grease	22.7
Temperature, Water	Temperature	22.4
Copper	Metals (other than Mercury)	17.0
Cadmium	Metals (other than Mercury)	12.4
Silver	Metals (other than Mercury)	12.4
pH	pH/Acidity/Caustic Conditions	12.2

Top of page

Wyoming Probable Sources of Impairments
for Threatened and Impaired Rivers and Streams
Reporting Year 2008

Description of this table

Probable Source	Probable Source Group	Miles Threatened or Impaired
Source Unknown	Unknown	800.7
Irrigated Crop Production	Agriculture	162.4
Natural Sources	Natural/Wildlife	158.5
Grazing In Riparian Or Shoreline Zones	Agriculture	143.5
Non-Point Source	Unspecified Nonpoint Source	100.6
Petroleum/Natural Gas Production Activities (Permitted)	Industrial	44.7
Habitat Modification - Other Than Hydromodification	Habitat Alterations (Not Directly Related To Hydromodification)	36.0
Discharges From Municipal Separate Storm Sewer Systems (Ms4)	Urban-Related Runoff/Stormwater	29.6
Loss Of Riparian Habitat	Habitat Alterations (Not Directly Related To Hydromodification)	15.4
Subsurface (Hardrock) Mining	Resource Extraction	10.5
Impacts From Abandoned Mine Lands (Inactive)	Resource Extraction	6.5
Sources Outside State Jurisdiction Or Borders	Other	6.5
Municipal Point Source Discharges	Municipal Dishcarges/Sewage	6.3

Top of page

---

Wyoming Assessed Waters
Summary of Water Quality Attainment for Lakes, Reservoirs, and Ponds
Reporting Year 2008

Description of this table Assessed Status Acres Assessed 6,655.6 Unassessed 318,392.5 Total Acres 325,048.0

Description of this table Attainment Status Acres Good 418.0 Threatened .0 Impaired 6,237.6 Total Acres Assessed 6,655.6

Description of this table TMDL Development Status Acres All TMDLs completed .0 TMDL alternative .0 Non-pollutant impairment .0 TMDL needed 6,237.6 Total Threatened and Impaired 6,237.6

Top of page

Wyoming Assessed Waters
Designated Use Support for Lakes, Reservoirs, and Ponds
Reporting Year 2008*

* 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
Aquatic Life Other Than Fish	6,655.6	6.3	.0	93.7
Cold Water Fishery	433.4	96.4	.0	3.6
Warm Water Fishery	6,075.8	.0	.0	100.0
Wildlife	146.4	.0	.0	100.0

Top of page

Wyoming Causes of Impairment
for Threatened and Impaired Lakes, Reservoirs, and Ponds
Reporting Year 2008

Description of this table

Cause of Impairment	Cause of Impairment Group	Acres Threatened or Impaired
Sedimentation/Siltation	Sediment	6,091.2
Selenium	Metals (other than Mercury)	145.4
Phosphate	Nutrients	15.4

Top of page

Wyoming Probable Sources of Impairments
for Threatened and Impaired Lakes, Reservoirs, and Ponds
Reporting Year 2008

Description of this table

Probable Source	Probable Source Group	Acres Threatened or Impaired
Irrigated Crop Production	Agriculture	6,221.2
Non-Point Source	Unspecified Nonpoint Source	6,091.2
Municipal Point Source Discharges	Municipal Dishcarges/Sewage	15.4
Discharges From Municipal Separate Storm Sewer Systems (Ms4)	Urban-Related Runoff/Stormwater	15.4

Top of page

---

Wyoming Causes of Impairment for Reporting Year 2008

Description of this table

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.
Cause of Impairment Group	Size of Assessed Waters with Listed Causes of Impairment
	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
Ammonia	45.4
Flow Alteration(s)	32.2
Habitat Alterations	178.4
Metals (other than Mercury)	396.7	145.4
Nutrients		15.4
Oil and Grease	22.7
Pathogens	790.7
pH/Acidity/Caustic Conditions	12.2
Salinity/Total Dissolved Solids/Chlorides/Sulfates	64.8
Sediment	63.9	6,091.2
Temperature	22.4

Top of page

---

Wyoming Probable Sources Contributing to Impairments
for Reporting Year 2008

Description of this table

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	Size of Assessed Waters with Probable Sources of Impairments
	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)
Agriculture	306.0	6,221.2
Habitat Alterations (Not Directly Related To Hydromodification)	51.4
Industrial	44.7
Municipal Dishcarges/Sewage	6.3	15.4
Natural/Wildlife	158.5
Other	6.5
Resource Extraction	17.0
Unknown	800.7
Unspecified Nonpoint Source	100.6	6,091.2
Urban-Related Runoff/Stormwater	29.6	15.4

Top of page

---

Wyoming TMDL Alternatives by Cause of Impairment 2008

Description of this table

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)
Oil and Grease	1	21

Total: 1 TMDL Alternatives

Top of page

---

Wyoming Previously Impaired Waters Now Attaining All Uses

No previously impaired waters reported as attaining all uses.

Top of page

---

Wyoming Causes of Impairment for 303(d) Listed Waters

Description of this table

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
Pathogens	68
Metals (other than Mercury)	23
Habitat Alterations	12
Sediment	5
Ammonia	4
Salinity/Total Dissolved Solids/Chlorides/Sulfates	3
pH/Acidity/Caustic Conditions	2
Temperature	1
Flow Alteration(s)	1
Oil and Grease	1
Nutrients	1

Total: 121 Causes of Impairment

Top of page

---

Wyoming Cumulative TMDLs by Pollutant

This chart includes TMDLs since October 1, 1995.

Description of this table

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
Fecal Coliform	83	84
Total Residual Chlorine	50	52
Chlorine	48	48
Ammonia, Un-ionized	47	48
Ammonia	33	34
Chlorine, Residual (Chlorine Demand)	13	13
Fecal	12	12
Radium 226	10	11
Chlorides	7	7
Chloride	5	5
Iron	5	5
Radium	4	4
Arsenic	3	3
Zinc	3	3
Copper	2	2
Manganese	2	2
Pentachlorophenol (PCP)	2	2
Phenols	2	2
Selenium	2	2
Temperature	2	2
Chromium	1	1
Chromium IV	1	1
Escherichia Coli (E. Coli)	1	1
Nitrate	1	1
Nitrates	1	1
Sulfide	1	1
Total Dissolved Solids (TDS)	1	1

Total: 342 TMDLs; 348 Causes of Impairment Addressed

Top of page

Wyoming Cumulative Number of TMDLs

EPA Fiscal Year starts October 1 and ends September 30.

Description of this table

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	83	84
1998	9	9
1999	41	41
2000	12	12
2001	10	10
2002	13	13
2003	11	11
2004	71	75
2005	39	39
2006	16	16
2007	37	38

Total: 342 TMDLs; 348 Causes of Impairment Addressed

Top of page

---

TMDL Document Search

Top of page

• EPA Home
• Privacy and Security Notice
• Contact Us