Magic Spillway dam
Magic Spillway
Magic Spillway, located in Shoshone, Idaho, is a privately owned concrete dam completed in 1910 for hydroelectric and irrigation purposes on the Big Wood River. With a height of 50 feet and a spillway width of 1200 feet, this structure has a storage capacity of 195,000 acre-feet and a maximum discharge of 100,000 cubic feet per second. The dam is regulated by the Federal Energy Regulatory Commission and inspected regularly to ensure its safety and compliance with state regulations.
Despite its age, Magic Spillway remains a critical infrastructure for water resource management in the region, with a high hazard potential due to its location and design. The dam's risk assessment has been classified as very high, emphasizing the importance of proper maintenance and emergency preparedness. While its condition assessment is currently not available, efforts are being made to ensure that the spillway meets guidelines for emergency action plans and risk management measures.
As a key component in the water resources network of Blaine County, Idaho, Magic Spillway serves as a reminder of the intersection between water infrastructure, climate resilience, and regulatory oversight. Its history and operational significance make it a focal point for enthusiasts and professionals interested in hydroelectric power generation, dam safety, and sustainable water management practices.
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 Magic Spillway -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Big Wood River Bl Magic Dam Nr Richfield Id | 900 cfs | → |
| Big Wood River At Stanton Crossing Nr Bellevue Id | 252 cfs | → |
| Camas Creek Nr Blaine Id | 11 cfs | → |
| Silver Creek At Sportsman Access Nr Picabo Id | 110 cfs | → |
| Big Wood R At S Broadford Bridge Nr Bellevue | 821 cfs | → |
| Big Wood River At Hailey Id Total Flow | 848 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Magic Spillway.
Campgrounds
- Magic Reservoir
- Myrtle Point - Magic Reservoir
- Myrtle Point Recreation Site
- Lava Point - Magic Reservoir
- Lava Recreation Site
- Moonstone Recreation Site
Paddle runs
- Headwaters To Sawtooth Nf Boundary
- Headwaters To Confluence With Corral Creek
- Headwaters To Confluence With Button Creek
- Headwaters To Section 7
- Headwaters To Confluence With Little Wood River
- West Fork Big Wood River To Confluence With Big Wood River
More reservoirs
Track Magic Spillway 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 Magic Spillway
Where does the data for Magic Spillway 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 Magic Spillway.