Dam Report

Lahontan dam

Nevada, USA Carson River Hazard High
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Dam height
120ft
Hazard rating
High
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Lahontan -- None dam
Lahontan None · Carson River
About this dam

Lahontan

Lahontan, located in Fallon, Nevada, is a federal-owned dam designed by the Bureau of Reclamation and completed in 1915 with the primary purpose of flood risk reduction. It stands as an earth dam with a height of 120 feet and a hydraulic height of 115 feet, providing maximum storage capacity of 422,800 acre-feet. The dam also serves other purposes such as hydroelectric power generation, irrigation, and recreation, making it a vital water resource in the region.

With a hazard potential rated as high and a moderate risk assessment score of 3, Lahontan is a critical infrastructure that requires regular inspections and maintenance by the Bureau of Reclamation. The dam has a spillway width of 400 feet and associated structures for controlled water release, ensuring safety during high water events. While the condition assessment is currently not available, Lahontan's emergency action plan was last revised in 2017, showcasing the ongoing efforts to enhance its resilience to potential risks and emergencies.

As a key feature along the Carson River, Lahontan plays a significant role in managing water resources and mitigating flood risks in Churchill County. Its historical significance, coupled with its multi-purpose functionality, highlights the importance of sustainable water management practices and the need for continued monitoring and maintenance to ensure the safety and reliability of this essential infrastructure for the community and the environment.

StateNone
River / streamCarson River
NID IDNV10123
Owner typeFederal
Primary purposeFlood Risk Reduction
Dam typeEarth
Year built1915
Dam height120 ft
Dam length1,915 ft
Max storage422,800 AF
Normal storage317,200 AF
Surface area15,000.0 ac
Drainage area1,903.0 sq mi
Hazard potentialHigh
ConditionNot Available
Last inspectionThu, 13 Aug 2020 00:00:00 GMT

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 Lahontan -- inflows here typically show up in storage 24-72 hours later.

Track Lahontan 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 Lahontan

Where does the data for Lahontan 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.