Long Lake dam
Long Lake
Long Lake, located in Hoffman, Minnesota, is a state-regulated water resource managed by the Minnesota Department of Natural Resources. This reservoir on the Chippewa River was completed in 1938 and serves various purposes, with a primary dam type of "Other" and a buttress core type. The dam stands at a height of 6 feet and has a hydraulic height of 1.9 feet, with a storage capacity of 2255 acre-feet and a surface area of 218 acres.
With a drainage area of 143 square miles, Long Lake has a low hazard potential and is in satisfactory condition according to a 2009 assessment. The reservoir has a normal storage capacity of 1640 acre-feet and a maximum discharge of 1470 cubic feet per second. Despite being unlisted for spillway type and having no associated locks, Long Lake provides valuable water resources for the region and is subject to state inspection, permitting, and enforcement to ensure its safety and efficiency for water and climate enthusiasts.
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 Long Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Otter Tail River Bl Orwell D Nr Fergus Falls | 520 cfs | → |
| Otter Tail River Near Elizabeth | 358 cfs | → |
| Long Prairie River At Long Prairie | 174 cfs | → |
| Bois De Sioux River Near White Rock | 100 cfs | → |
| Bois De Sioux River Near Doran | 159 cfs | → |
| Red River Of The North At Wahpeton | 740 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Long Lake.
⚓ Boat launches
- Twin Lakes Road Southwest Douglas County
- Viking Trail 16246, Douglas County
- Douglas County
- Viking Trail Douglas County
- Brophy Park Road Northwest 1599, Douglas County
- Latoka Beach Road Southwest 3078, Douglas County
Track Long Lake 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 Long Lake
Where does the data for Long 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 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 Long Lake.