Thomson Dam No. 9 dam
Thomson Dam No. 9
Thomson Dam No. 9, located in Thomson, Minnesota, stands as a vital structure along the St. Louis River, serving multiple purposes including hydroelectric power generation and recreation. Completed in 1907, this gravity dam stands at a height of 11 feet and has a length of 100 feet, with a storage capacity of 4,352 acre-feet. The dam is under the jurisdiction of the Minnesota Department of Natural Resources and is regulated by the Federal Energy Regulatory Commission.
With its high hazard potential, Thomson Dam No. 9 is subject to regular state inspections and enforcement to ensure its safety and integrity. The dam is part of a network of 13 associated structures, contributing to the management of water resources in the area. The location of the dam in Carlton County, Minnesota, highlights its significance in water resource management and climate resilience efforts in the region.
Managed by the St. Paul District of the US Army Corps of Engineers, Thomson Dam No. 9 plays a crucial role in water storage and flow regulation along the St. Louis River. Its history, design, and purpose make it a key asset for both water management and recreational activities, showcasing the intersection of human infrastructure and natural resources in the context of climate change and sustainable development.
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 Thomson Dam No. 9 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. Louis River At Scanlon | 2,770 cfs | → |
| Nemadji River Near South Superior | 508 cfs | → |
| Knife River Near Two Harbors | 121 cfs | → |
| Bois Brule River At Brule | 167 cfs | → |
| St. Croix River Near Danbury | 1,320 cfs | → |
| Kettle River Below Sandstone | 476 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Thomson Dam No. 9 .
Boat launches
- Saint Louis River -- Oliver - Sajac Memorial Park Access
- Woodstock Bay
- Pokegama River -- Access
- Saint Louis River -- Arrowhead Fishing Pier Access
- Billings Park Boat Launch
- Midway Road Saint Louis County
Campgrounds
- Jay Cooke State Park
- Silver Creek Backpack Campsite
- High Landing Backpack Campsite
- Ash Ridge Backpack Campsite
- Lost Lake Backpack Campsite
- Spafford City Park Campground
Paddle runs
- Upper Saint Louis
- Carlton County State Aid Highway #12 Bridge To The Site Of Old Sandstone Hydroelectric Dam
- The Site Of Old Sandstone Hydroelectric Dam To The Confluence With St. Croix River
- The Boundary Between Logan And Workman Townships In Aitkin County To The Dam Entrance Of The Flood Diversion Channel
Track Thomson Dam No. 9 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 Thomson Dam No. 9
Where does the data for Thomson Dam No. 9 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 High 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 Thomson Dam No. 9 .