Protecting Public Health and the Environment.

Kootenai and Moyie Rivers Subbasins

Subbasins at a Glance

Hydrologic Unit Codes 17010101, 17010104, 17010105
Size 1,080 square miles (691,200 acres)

Water Bodies with EPA-Approved TMDLs (Category 4a)

Lower Kootenai River Subbasin: Ball Creek, Blue Joe Creek, Boulder Creek, Boundary Creek and tributaries, Brush Creek, Caribou Creek, Cow Creek, Curley Creek, Deep Creek, Fall Creek, Flemming Creek, Grass Creek, Long Canyon Creek, Lower Deep Creek, Mission Creek, Myrtle Creek, Rock Creek, Ruby Creek, Smith Creek, Snow Creek, Trail Creek, Trout Creek

Moyie River Subbasin: Canuck Creek, Deer Creek, Gillon Creek, Miller Creek, Meadow Creek, Moyie River tributaries, Round Prairie Creek, Skin Creek

Beneficial Uses Affected Cold water aquatic life, salmonid spawning
Major Land Uses Timber harvest, recreation, designated wilderness, mineral extraction, dryland agriculture, rangeland
Date Approved by EPA

January 2007
EPA Approval Letter

Addendum Approved by EPA

October 2014
EPA Approval Letter

Subbasin Characteristics

The Lower Kootenai and Moyie River subbasins remained in a relatively natural condition until the early twentieth century when miners, loggers, and ranchers began to settle the area. In recent years, timber harvest and grazing have been restricted to the floodplain of the lower portion of the Kootenai River. Excessive sediment in the subbasin comes primarily from road crossings and encroachment. Temperature is most affected by stream shading. Metals and pH exceedances stem from historic mining activity near the headwaters of Blue Joe Creek.

2006 Subbasin Assessment and TMDL

Water temperatures are an issue in the Lower Kootenai and Moyie River subbasins. A subbasin assessment and TMDL for water temperatures was developed in 2005; however, before it was completed, the Kootenai and Moyie River Subbasin Watershed Advisory Group suggested it be incorporated into this TMDL.

An assessment of temperature data in 2002 indicated that all monitored streams in the Lower Kootenai and Moyie River subbasins exceed Idaho temperature criteria. When all streams, including undisrupted streams, have numeric criteria exceedances, a special look at natural conditions must be taken into account. The Lower Kootenai and Moyie River subbasins are located in the northern-most portion of Idaho at relatively low elevations. Throughout the state, it has been demonstrated that water temperatures are most strongly affected by air temperatures, which directly relate to elevation.

Metals and pH are identified as pollutants for Blue Joe Creek. During the initial 1998 assessment, Blue Joe Creek was void of aquatic insect life and was impaired. The source of metals and associated pH issues is the now abandoned Continental Mine. Through environmental cleanup activities, both DEQ and the US Forest Service have been working to reduce metals and pH loading. All reasonable TMDL implementation activities for metals and pH loading are complete, and Blue Joe Creek is in a state of recovery. Therefore, TMDLs for metals and pH for Blue Joe Creek were not developed.

The 1998 §303(d) list includes the Moyie River, from the Moyie River Dam to its confluence with the Kootenai River. Excess sediment is the listed pollutant, and based on the 1998 determination, a TMDL would be required. DEQ does not have Beneficial Use Reconnaissance Program (BURP) monitoring data on this section of the Moyie River and believes the sediment listing decision was based on anecdotal understandings and information. DEQ has evidence that the listing resulted from a single fine sediment deposition event and that the stream has recovered since that event. DEQ recommends removing the Moyie River from the §303(d) list and did not develop a TMDL for this river.

Blue Joe Creek, Boulder Creek, and Caribou Creek have also been removed as candidates for sediment TMDL development for the following reasons:

  • Draft TMDLs demonstrated that current sediment generating conditions are better than those showing full support of the beneficial uses.
  • Stressor Identification Analysis performed by DEQ supports removal of these three streams as TMDL candidates.

2006 TMDL: Streams and Pollutants for Which TMDLs Were Developed

Boundary Creek
Temperature
Cow Creek
Sediment
Deep Creek
Temperature, sediment

2014 Addendum

The Idaho Department of Environmental Quality (DEQ) has developed temperature TMDLs for 17 streams (23 AUs) in the Lower Kootenai River subbasin and 9 streams (11 AUs) in the Moyie River subbasin that were placed on the 2002 §303(d) list of impaired waters, or subsequent lists, for reasons associated with temperature criteria exceedances. In the Lower Kootenai River subbasin, 3 additional AUs that were not identified as being impaired by temperature pollution were included in this TMDL addendum as unlisted but impaired TMDLs (AUs ID17010104PN030_03, ID17010104PN033_03, and ID17010104PN039_02).

Effective target shade levels were established for 37 AUs based on the concept of maximum shading under potential natural vegetation resulting in natural background temperature levels. Shade targets were derived from effective shade curves developed for similar vegetation types in Idaho. Existing shade was determined from aerial photo interpretation that was partially field verified with Solar Pathfinder data. Target and existing shade levels were compared to determine the amount of shade needed to bring water bodies into compliance with temperature criteria in Idaho’s water quality standards (IDAPA 58.01.02).

In the Lower Kootenai River subbasin, 4 AUs previously listed for temperature pollution were found through stressor identification likely to be affected by pollutants other than temperature. These AUs will require additional monitoring and investigation. All other AUs in the Lower Kootenai River subbasin lack shade to some degree, although many reaches met reference conditions. Lowland streams affected by agricultural land uses (i.e., Cow, lower Fleming, Rock, and Curley Creeks) tend to be the most affected. Some forested systems (Boulder and Smith Creeks) have substantial hydrologic effects that widen streams and lower near-stream shade quality.

In the Moyie River subbasin, all AUs examined lack shade and most require substantial reductions in excess loads to meet targets. The Meadow Creek watershed appears to be in the best condition overall with respect to shade; whereas Deer Creek, Round Prairie Creek, and others have patches of shade deficits.

Target shade levels for individual stream segments should be the goal managers strive for with future implementation plans. Managers should focus on the largest differences between existing and target shade as locations to prioritize implementation efforts.

2014 Addendum: Streams and Pollutants for Which TMDLs Were Developed

Lower Kootenai River Subbasin

Description Assessment Unit Pollutant
Ball Creek ID17010104PN011_02
ID17010104PN011_02a
Temperature
Blue Joe Creek ID17010104PN004_02 Temperature
Boulder Creek ID17010104PN032_03
ID17010104PN033_03
Temperature
Brush Creek ID17010104PN039_02 Temperature
Caribou Creek ID17010104PN017_02 Temperature
Cow Creek ID17010104PN030_03 Temperature
Curley Creek ID17010104PN035_03 Temperature
Fall Creek ID17010104PN021_03 Temperature
Fleming Creek ID17010104PN036_03 Temperature
Grass Creek ID17010104PN003_02
ID17010104PN003_03
Temperature
Long Canyon Creek ID17010104PN008_02 Temperature
Mission Creek

ID17010104PN038_03
ID17010104PN040_03

Temperature
Myrtle Creek ID17010104PN014_02
ID17010104PN013_03
Temperature
Rock Creek ID17010104PN037_03 Temperature
Ruby Creek ID17010104PN020_03 Temperature
Smith Creek ID17010104PN006_03
ID17010104PN007_03
ID17010104PN005_04
Temperature
Snow Creek ID17010104PN016_03 Temperature
Trail Creek ID17010104PN026_03 Temperature
Trout Creek ID17010104PN010_03 Temperature

Moyie River Subbasin

Description Assessment Unit Pollutant
Canuck Creek ID17010105PN007_02 Temperature
Deer Creek ID17010105PN004_02
ID17010105PN004_03
Temperature
Gillon Creek ID17010105PN009_02 Temperature
Miller Creek ID17010105PN011_02 Temperature
Meadow Creek ID17010105PN012_02
ID17010105PN012_03
Temperature
Moyie River Tributaries ID17010105PN002_02
ID17010105PN006_02
Temperature
Round Prairie Creek ID17010105PN010_03 Temperature
Skin Creek ID17010105PN003_02 Temperature

Subbasin Documents


Staff Contacts

TMDL Technical Lead
Robert Steed
DEQ Coeur d'Alene Regional Office
2110 Ironwood Parkway
Coeur d'Alene, ID 83814
(208) 769-1422
robert.steed@deq.idaho.gov

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