Northern Pacific Reservoir Dam dam
Northern Pacific Reservoir Dam
The Northern Pacific Reservoir Dam, located in Jefferson County, Montana, is a privately-owned structure designed for water supply purposes on McClellan Creek. Completed in 1935, this gravity dam stands at a height of 35 feet and has a storage capacity of 173 acre-feet. With a maximum discharge of 800 cubic feet per second, the dam serves as a vital resource for water management in the region.
Despite its age, the Northern Pacific Reservoir Dam is still in operation and regulated by the Montana Department of Natural Resources and Conservation (DNRC). With a high hazard potential, the dam plays a crucial role in maintaining water levels and providing essential water resources to the surrounding area. The dam's condition assessment is currently listed as "Not Rated," indicating a need for further evaluation to ensure its continued safety and effectiveness.
As a key feature in the water infrastructure of East Helena, the Northern Pacific Reservoir Dam serves as a reminder of the importance of proper dam maintenance and regulation in the face of changing climate conditions. With its historic significance and ongoing role in water supply, this gravity dam continues to be a valuable asset in managing water resources in the region.
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 Northern Pacific Reservoir Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Prickly Pear Creek Near Clancy Mt | 36 cfs | → |
| Tenmile Creek Near Helena Mt | 26 cfs | → |
| Missouri River Bl Hauser Lake Nr Helena Mt | 3,230 cfs | → |
| Tenmile Creek Near Rimini Mt | 17 cfs | → |
| Boulder River Near Boulder Mt | 176 cfs | → |
| Missouri River Bl Holter Dam Nr Wolf Cr Mt | 3,280 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Northern Pacific Reservoir Dam.
Boat launches
- Helena Regulating Reservoir Road Lewis And Clark County
- Smith Road Helena Valley Northeast
- Cross Drive Helena Valley Northeast
- York Road Lewis And Clark County
- Canyon Ferry Road 7604, Lewis And Clark County
- Canyon Ferry Road Lewis And Clark County
Campgrounds
- Spokane Bay
- Fort Harrison Rv Military - National Guard
- Devils Elbow Campground
- White Sandy Campground
- Black Sandy State Park
- White Sandy
Fishing spots
- Helena Valley Regulating Reservoir
- Spring Meadow Lake
- Hauser Reservoir
- Prickly Pear Creek
- Park Lake
- Missouri River Fishing Access Site
Track Northern Pacific Reservoir Dam 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 Northern Pacific Reservoir Dam
Where does the data for Northern Pacific Reservoir Dam 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 High 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 Northern Pacific Reservoir Dam.