Upper Twin Lakes dam
Upper Twin Lakes
Upper Twin Lakes, located in Ravalli County, Montana, is a man-made reservoir primarily used for irrigation purposes. Constructed in 1964 by the USDA NRCS, this earth dam stands at a height of 14 feet and has a storage capacity of 220 acre-feet. The dam spans 450 feet in length and is situated on Lost Horse Creek, with a surface area of 31 acres and a drainage area of 1 square mile.
Despite being regulated by the DNRC and rated as having low hazard potential, Upper Twin Lakes has not undergone a recent condition assessment. The spillway, with a width of 13 feet, is uncontrolled, and the dam is categorized as having a moderate risk level. The last inspection dates back to 1989, raising questions about the current state of the dam's infrastructure and safety measures. With its picturesque location and historical significance, Upper Twin Lakes presents an opportunity for further exploration and evaluation by water resource 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 Upper Twin Lakes -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Bitterroot River Near Darby Mt | 1,910 cfs | → |
| Bitterroot River At Bell Crossing Nr Victor Mt | 2,960 cfs | → |
| West Fork Bitterroot River Nr Conner Mt | 641 cfs | → |
| Middle Fork Rock Cr Nr Philipsburg Mt | 262 cfs | → |
| Selway River Nr Lowell Id | 7,320 cfs | → |
| Bitterroot River Near Missoula Mt | 3,960 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Upper Twin Lakes.
Boat launches
- Lake Como Road Ravalli County
- Old Darby Road Ravalli County
- Darby Boat Ramp
- Rocky Mountain Road Ravalli County
- Idaho County
- Paradise Boating Site
Campgrounds
- Schumaker
- Schumaker Campground
- Bear Creek Pass Campground
- Elk Summit Campground
- Elk Summit
- Three Frogs Campground
Fishing spots
Paddle runs
- Blodgett Lake Dam, Sec. 27, T6n, R23w To S-B Wilderness Boundary, Sec. 17, T6n, R21w
- Lick Creek Bridge, Sec. 18, T4n, R21w To Bear Creek Pass, Sec. 5, T4n, R23w And Twin Lakes Dam, Sec. 29, T5n, R23w
- S-B Boundary, Sec. 17, T6n, R21w To Westside Of Blodgett Campground, Sec. 17, T6n, R22w
- West Side Blodgett Campground, Sec. 17, T6n, R21w To Bitterroot Forest Boundary, Sec. 17, T6n, R21w
- Selway River, Sec. 16, T31n, R13e To Headwaters
- 32nd Street To Smelter
Track Upper Twin Lakes 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 Upper Twin Lakes
Where does the data for Upper Twin Lakes 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 Upper Twin Lakes.