Sun River Diversion dam
Sun River Diversion
The Sun River Diversion, also known as Diversion Lake, is a federal water management structure located in Simms, Montana. Completed in 1914 by the Bureau of Reclamation, this concrete dam serves primarily for irrigation purposes along the North Fork Sun River. With a height of 132 feet and a storage capacity of 6,395 acre-feet, the dam spans 261 feet in length and covers a surface area of 202 acres.
Managed by the Bureau of Reclamation, the Sun River Diversion has a low hazard potential and a moderate risk assessment rating. The uncontrolled spillway, with a width of 140 feet, can handle a maximum discharge of 34,000 cubic feet per second. The dam is situated in a picturesque location in Teton County, Montana, and plays a crucial role in regulating water flow for agricultural needs in the region.
Despite its age, the Sun River Diversion is a reliable and essential water resource infrastructure in the area. With regular inspections and a well-maintained structure, this dam continues to support the irrigation needs of the local community while preserving the natural environment of the North Fork Sun River.
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 Sun River Diversion -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Sun River Bl Diversion Dam Nr Augusta Mt | 661 cfs | → |
| North Fork Sun River Near Augusta Mt | 693 cfs | → |
| South Fork Sun River Near Augusta Mt | 540 cfs | → |
| Sun River Bl Willow Cr Nr Augusta Mt | 645 cfs | → |
| Teton River Bl South Fork Nr Choteau Mt | 349 cfs | → |
| Sun River At Simms Mt | 688 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Sun River Diversion.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About Sun River Diversion
Where does the data for Sun River Diversion 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.