Dam Report

Garrison Dam dam

North Dakota, USA Missouri River Hazard High
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Tonight low
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Dam height
210ft
Hazard rating
High
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Garrison Dam -- None dam
Garrison Dam None · Missouri River
About this dam

Garrison Dam

Garrison Dam, also known as Lake Sakakawea, is a federal-owned hydroelectric dam located on the Missouri River in Stanton, North Dakota. Completed in 1953, the dam serves multiple purposes including flood risk reduction, hydroelectric power generation, irrigation, navigation, and recreation. With a structural height of 210 feet and a dam volume of 66.5 million cubic yards, Garrison Dam plays a crucial role in managing water resources in the region.

Although Garrison Dam has been effective in reducing floods, there is still a high risk associated with the potential loss of life and large-scale consequences if a breach were to occur. The US Army Corps of Engineers (USACE) actively monitors and maintains the dam, while also working with local emergency management agencies to improve preparedness and public awareness of flood risks. Additionally, ongoing risk management measures and evaluations are being pursued to further reduce risks associated with the dam, including upgrades to prevent erosion of the dam's foundation and repairs to improve the spillway's resiliency during future flood events.

As part of the USACE Dam Safety Program, communities downstream of Garrison Dam are encouraged to stay informed about water management in the Missouri River basin and to have evacuation plans in place in case of extreme floods. The importance of understanding and mitigating individual risks in the face of potential dam failures underscores the critical role that Garrison Dam plays in water resource management and climate resilience efforts in the region.

StateNone
River / streamMissouri River
NID IDND00145
Owner typeFederal
Primary purposeHydroelectric
Dam typeEarth
Year built1953
Dam length11,300 ft
Max storage26,000,000 AF
Normal storage18,500,000 AF
Surface area133,000.0 ac
Drainage area180,940.0 sq mi
Hazard potentialHigh
ConditionNot Available
Last inspectionFri, 15 Jun 2018 07:00:00 GMT
EAP preparedYes

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.
Detailed forecast

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.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

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Deep dive

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.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
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Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

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Regional inflow

Nearby streamflow gauges

USGS streamgauges around Garrison Dam -- inflows here typically show up in storage 24-72 hours later.

Track Garrison 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.

FAQ

About Garrison Dam

Where does the data for Garrison 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.

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