Portneuf dam
Portneuf
Portneuf, also known as Chesterfield Reservoir, is a privately owned dam located in Caribou, Idaho, near the city of Lava Hot Springs. Built in 1912, this earth and stone dam stands at a height of 54.6 feet and has a storage capacity of 20,504 acre-feet. The dam is situated on the Portneuf River, a tributary of the Snake River, and serves multiple purposes beyond flood control, making it a vital resource for the region.
Despite its fair condition assessment and high hazard potential, Portneuf has been regulated and inspected by the Idaho Department of Water Resources. The dam features an uncontrolled spillway with a width of 40 feet and outlet gates for controlled release of water. With a risk assessment rating of moderate, the dam is actively managed to mitigate potential risks and ensure the safety of downstream communities in the event of an emergency. Overall, Portneuf plays a crucial role in water resource management and climate resilience efforts 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 Portneuf -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Portneuf River At Topaz Id | 201 cfs | → |
| Marsh Creek Nr Mccammon Id | 26 cfs | → |
| Blackfoot River Ab Reservoir Nr Henry Id | 62 cfs | → |
| Grays Lk Div To Blackfoot R Basin Nr Wayan Id | 5 cfs | → |
| Portneuf River At Pocatello Id | 68 cfs | → |
| Blackfoot River Nr Shelley Id | 588 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Portneuf.
Campgrounds
- Pebble Guard Station
- Big Springs Campground - Caribou
- Sagehen Flat
- Sage Hen Flats Campground
- Grave's Creek Campground
- Graves Creek
Paddle runs
- Blackfoot Wolverine Canyon Run
- Black Canyon - Highway 34 To Grace Powerhouse
- Mainstem West Of Palisades Reservoir Including North Fork And Deadman Creek To Palisades Reservoir
- South Fork Snake River
- Palisade Dam To Lorenzo (South Fork)
- Palisades Dam To Confluence With Pine Creek
Track Portneuf 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 Portneuf
Where does the data for Portneuf 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 Portneuf.