Saint Marys Diversion dam
Saint Marys Diversion
The Saint Marys Diversion, located in Glacier, Montana, is a Federal-owned structure managed by the Bureau of Reclamation. Completed in 1920, this concrete dam stands 29 feet tall and spans 198 feet in length, primarily serving the purpose of irrigation along the Saint Mary River. With a storage capacity of 100 acre-feet, the dam has a low hazard potential and a moderate risk assessment rating.
Despite its age, the Saint Marys Diversion continues to play a crucial role in water resource management in the region. With no state jurisdiction or regulation, the Bureau of Reclamation oversees its operations, inspections, and regulatory compliance. The dam's uncontrolled spillway, with a width of 190 feet, further enhances its ability to manage water flow efficiently.
As a key piece of infrastructure in the area, the Saint Marys Diversion presents a captivating opportunity for water resource and climate enthusiasts to explore the intersection of historical engineering achievements and modern water management practices. Its strategic location and design highlight the ongoing importance of sustainable water use and infrastructure maintenance in the face of changing climate conditions.
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 Saint Marys Diversion -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. Mary Canal At Intake Near Babb Mt | 54 cfs | → |
| St. Mary River Near Babb Mt | 1,180 cfs | → |
| St. Mary Canal At St. Mary Crossing Near Babb Mt | 602 cfs | → |
| Swiftcurrent Creek At Many Glacier Mt | 190 cfs | → |
| Swiftcurrent Cr Ab Swiftcurrent Lk At Many Glacier | 113 cfs | → |
| N F Milk River Ab St Mary Ca Nr Browning Mt | 7 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Saint Marys Diversion.
Campgrounds
- Leaning Tree Cafe And Campground
- Chewing Backbones Campground
- Ducklake Campground.
- St Mary
- St. Mary Lake - Glacier National Park
- Poia Lake
Fishing spots
Paddle runs
- Moccasin Creek To West Glacier (John Stevens Canyon)
- West Glacier To Blankenship Bridge
- Big Creek To Glacier Rim
- Polebridge To Big Creek
- Essex To Moccasin Creek
- Glacier Rim To Blankenship Bridge And Confluence
More reservoirs
Track Saint Marys Diversion 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 Saint Marys Diversion
Where does the data for Saint Marys 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 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 Saint Marys Diversion.