Dam Report

Granite Springs dam

Wyoming, USA Middle Crow Creek Hazard High
Today high
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Tonight low
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Dam height
90ft
Hazard rating
High
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Granite Springs -- None dam
Granite Springs None · Middle Crow Creek
About this dam

Granite Springs

Granite Springs, also known as Cheyenne #2, is a historic masonry dam located in Laramie, Wyoming, serving as a crucial water supply source for the city of Cheyenne. Completed in 1904, this architectural marvel stands at a height of 90 feet and has a storage capacity of 5,780 acre-feet. Situated on Middle Crow Creek, the dam's primary purpose is to ensure reliable water access for the region, with a drainage area of 28.4 square miles and a maximum discharge rate of 29,800 cubic feet per second.

Despite its age, Granite Springs has been well-maintained, with regular inspections and a fair condition assessment as of June 2017. The dam features an uncontrolled spillway, two other controlled outlet gates, and a high hazard potential due to its critical role in water supply management. With a moderate risk assessment rating, ongoing risk management measures are in place to mitigate any potential hazards and ensure the safety and functionality of the structure. As a key infrastructure asset in the region, Granite Springs plays a vital role in water resource management and climate resilience efforts in Wyoming.

StateNone
River / streamMiddle Crow Creek
NID IDWY00001
Owner typeLocal Government
Primary purposeWater Supply
Dam typeMasonry
Year built1904
Dam height90 ft
Dam length423 ft
Max storage5,780 AF
Normal storage5,220 AF
Surface area190.0 ac
Drainage area28.4 sq mi
Hazard potentialHigh
ConditionFair
Last inspectionThu, 22 Jun 2017 12:00:00 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 Granite Springs -- inflows here typically show up in storage 24-72 hours later.

Track Granite Springs 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 Granite Springs

Where does the data for Granite Springs 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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Premium feature

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Manage alerts in the Snoflo app

Custom alerts are configured in the iOS app -- favorite this dam, set a threshold, and you'll get a push the moment conditions cross.

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