Loon Lake dam
Loon Lake
Loon Lake, located in Cass County, Minnesota, is a federally owned Earth dam constructed in 1969 by the USDA FS with a primary purpose that falls under the "Other" category. This dam stands at a height of 7 feet and spans 180 feet in length, with a storage capacity of 530 acre-feet. The reservoir's normal storage level is reported to be 370 acre-feet and serves a drainage area of 0.96 square miles, with a low hazard potential and a condition assessment that is currently "Not Rated."
Managed by the St. Paul District of the US Army Corps of Engineers, the dam has not undergone any modifications since its completion and has not been inspected since March 1974. Despite its age, the structure has not been assessed for its current condition, and no emergency action plan or inundation maps have been prepared. The dam poses a low risk due to its condition and hazard potential, but without a recent evaluation, there is uncertainty about its current safety and resilience in the face of potential climate challenges and water resource management issues.
As an integral part of the Willow River watershed, Loon Lake plays a crucial role in water storage and management in the region. Water resource and climate enthusiasts would find Loon Lake an intriguing case study for understanding the complexities of dam infrastructure, federal ownership, and the need for regular inspections and risk assessments to ensure the safety and reliability of critical water resources in Minnesota.
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 Loon Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mississippi River At Grand Rapids | 612 cfs | → |
| Prairie River Near Taconite | 98 cfs | → |
| Mississippi River At Aitkin | 2,120 cfs | → |
| Mississippi River Near Bemidji | 115 cfs | → |
| Mississippi River At Brainerd | 2,750 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Loon Lake.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About Loon Lake
Where does the data for Loon Lake 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 below 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.
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.