Thompson Falls - Main Channel Dam dam
Thompson Falls - Main Channel Dam
Thompson Falls - Main Channel Dam, located in Sanders, Montana, is a historic gravity dam completed in 1915 on the Clark Fork River. With a height of 50 feet and a length of over 1000 feet, the dam serves primarily for hydroelectric purposes, generating power from the flowing waters of the river. The dam has a normal storage capacity of 14,970 acre-feet and a maximum discharge rate of 175,000 cubic feet per second, making it a vital structure for water resource management in the area.
Owned privately, the Thompson Falls Dam is regulated by the Federal Energy Regulatory Commission and is inspected by the same agency. The dam's spillway type is controlled, with a width of 913 feet, and it is equipped with outlet gates for water control. Despite its low hazard potential, the dam is recognized for its very high risk assessment due to its age and structural integrity concerns, requiring ongoing risk management measures to ensure its continued safety and functionality. The dam is not state-regulated, inspected, or permitted, highlighting the significant federal oversight in its operation and maintenance.
The Thompson Falls - Main Channel Dam stands as a significant landmark in the region, providing hydroelectric power and water resource management for the surrounding area. With a rich history dating back over a century, the dam's engineering marvel continues to serve its primary purpose effectively while facing challenges related to its age and risk assessment. As a vital component of the Clark Fork River system, the dam's operation and maintenance remain crucial for ensuring sustainable water management and climate resilience in the face of changing environmental conditions.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Thompson Falls - Main Channel Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Prospect Creek At Thompson Falls Mt | 274 cfs | → |
| Thompson River Near Thompson Falls Mt | 556 cfs | → |
| St. Regis River Near St. Regis | 597 cfs | → |
| Clark Fork At St. Regis Mt | 12,200 cfs | → |
| Clark Fork Near Plains Mt | 38,100 cfs | → |
| Canyon Creek Ab Mouth At Wallace | 73 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Thompson Falls - Main Channel Dam.
Boat launches
Campgrounds
- Thompson Falls State Park
- Gold Rush
- Gold Rush Campground
- Copper King
- Copper King Campground
- Clark Memorial
Fishing spots
Paddle runs
- Vermilion River
- Willow Creek, Sec. 32, T24n, R29w To Noxon Reservoir, Sec. 14, T24n, R31w
- Slowery, Sec. 15, T17n, R27w To Sec. 31, T18n. R28w
- Cuttoff, Sec. 9, T18n, R27w To Sec. 34, T19n, R25w
- Boundary Proposed Addition Cabinet Mtns Wilderness, Sec. To Cabinet Gorge Reservoir
- East Fork Bull River, Headwaters, Sec. 13, T27n, R32w To Cabinet Mountains Wilderness Boundary, Sec. 3, T27n, R32w
Track Thompson Falls - Main Channel Dam in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Thompson Falls - Main Channel Dam
Where does the data for Thompson Falls - Main Channel Dam come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Thompson Falls - Main Channel Dam.