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Coeur d'Alene Tribal TMDLs
Lake Creek Sediment TMDL
| You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader. |
Lake Creek Sediment TMDL at a Glance
| Waterbody | Lake Creek, Idaho |
| Water Quality-limited? | Yes |
| Hydrologic Unit Code | 17010303 (Coeur d’Alene Lake) |
| Criteria of Concern | Narrative criteria for sediment |
| Designated Uses Affected | Cold water aquatic life |
| Environmental Indicators | Instream total suspended solids (TSS) concentration |
| Major Source(s) | Cropland erosion |
| Loading Capacity | 276.1 tons/year |
| Wasteload Allocation | 0 tons/year |
| Load Allocation | 276.1 tons/year |
| Margin of Safety | 0 tons/year (included implicitly) |
| Necessary Reduction | 71% |
An important water quality effort is now underway in Lake Creek. The U.S. Environmental Protection Agency (EPA) and Coeur d’Alene Tribe (CDAT), with significant participation from Idaho Department of Environmental Quality (IDEQ) are working together to improve Lake Creek’s water quality.
Why does Lake Creek Need a TMDL? Lake Creek is located in the Coeur d’Alene basin in Northern Idaho near the Washington state line and drains into Windy Bay on the western side of Lake Coeur d'Alene. This basin consists mostly of agricultural and forested lands. The portion of the Lake Creek which lies entirely within the Coeur d’Alene Reservation has been identified as an impaired waterbody because of excessive sediment in the creek and in need of a clean up plan or Total Maximum Daily Load (TMDL).
The increased sediment loadings have reduced the quality of pools necessary for fish spawning and winter survival. Sediment affects aquatic life uses in several ways, including the following:
- Sediment deposition can fill pools, reducing aquatic habitat, particularly for refuge and rearing.
- Sediment deposition can fill interstitial spaces between gravel, reducing spawning habitat by trapping the emerging fish and reducing the exchange of oxygen necessary for fish embryos.
- Suspended sediment and turbidity can prevent fish from seeing food in the water and can clog their gills.
- High levels of suspended sediment can also result in fish avoiding the stream.
Erosion from agriculture is the primary cause of sediment in the creek. Other causes include gully erosion, roads, soil creep and mass movement of soils.
What is a TMDL and What Does it Look Like? EPA, CDAT, and IDEQ have developed a draft TMDL, or Total Maximum Daily Load, which is required by the federal Clean Water Act. This draft TMDL determines the maximum amount of sediment which can enter Lake Creek and still protect the cold water aquatic community and salmonid spawning.
The TMDL is like a “pollution budget” for Lake Creek. It is the sum of the individual wasteload allocations for point sources, load allocations for nonpoint sources and natural background pollutants, plus an appropriate margin of safety. This TMDL:
- provides a written assessment of water quality problems
- identifies the pollutant sources that contribute to the problem
- sets pollutant allocations for these sources to point sources (e.g. sewage treatment plant discharges), nonpoint sources (e.g., runoff from fields, streets, or forest land) and naturally occurring sources (e.g., runoff from undisturbed lands).
What is the Analytical Approach and Bottom Line? The proposed TMDL uses a numeric instream total suspended solids (TSS) targets (40 mg/L) designed to maintain good fisheries and recommends future monitoring to assess improvements in aquatic habitat quality. With TSS , turbidity and flow data, this TMDL uses statistical analysis which determined 276.1 tons/year was the maximum of sediment that Lake Creek could receive and still protect the cold water aquatic community and salmonid spawning. This entire loading capacity was allocated to nonpoint sources of sediment, which will be a 71% reduction in existing sediment loading into the creek. Because there are no permitted point sources discharging sediment into the impaired portion of the creek, the wasteload allocation is 0.
What Happens Once the TMDL is Finalized? Once the TMDL is finalized, the CDAT will develop an implementation plan with extensive involvement from IDEQ, local agencies and the community. The main focus of the implementation plan will likely to be reducing sediment inputs from agricultural sources, restore riparian zones and mitigate flow disturbance and sedimentation due to forest roads. The CDAT plans to continue water quality monitoring to track water quality improvement.
Come to a Community Information Meeting Join us! EPA and the CDAT will host a community information meeting at Rose Creek Longhouse, 30030 S. Mitch Michael Drive, Worley, Idaho on Monday March 15 from 6:30 pm to 8:30 pm. The meeting will be an opportunity for you to learn more about the TMDL effort. Meet agency representatives and ask questions about the draft TMDL. Provide ideas and input into a plan to implement this TMDL.
For people with disabilities: Please contact Scott Fields to request for reasonable accommodations at (208) 686-0252, e-mail: sffields@cdatribe-nsn.gov, TTY: 1-800-877-8339 (ask for Jayne Carlin) by March 10.
Opportunity to Provide Written Comments The public will have a formal opportunity provide written comments on the draft TMDL. Persons wishing to comment on the TMDL must do so in writing by Monday April 5, 2004. Written comments must be postmarked by and sent to Jayne Carlin, Office of Water, U.S. EPA 1200 Sixth Avenue, Seattle, WA 98101. Comments may also be faxed to Jayne Carlin at EPA at (206) 553-0165 or e-mailed to by 5 pm on April 5 (call 206-553-8512 or e-mail carlin.jayne@epa.gov to confirm receipt). All comments should include the name, address, email address and telephone number of the commenter and a concise statement of the comment and the relevant facts upon which it is based. All comments will be considered before issuing the final TMDL.
Please contact agency representatives if you have any questions at:
| You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader. |
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Unit: Watershed Restoration
Point of contact: Jayne Carlin
Email: carlin.jayne@epa.gov
Phone Number: (206) 553-8512
Last Updated: 10/22/2004 03:47:31 PM
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