Granby dam
Granby
Granby is a federal-owned dam located in Grand County, Colorado, along the Colorado River. Built in 1949, this Earth-type structure stands at a height of 298 feet and serves primarily for hydroelectric and irrigation purposes. With a storage capacity of 539,760 acre-feet and a surface area of 7,260 acres, Granby plays a crucial role in water resource management in the region.
Managed by the Bureau of Reclamation, Granby has a high hazard potential and is regulated by the Colorado Department of Water Resources. The dam boasts a controlled spillway with a width of 40 feet and a maximum discharge capacity of 12,000 cubic feet per second. Despite its age, Granby continues to be a vital component of the water infrastructure system, providing essential services for the surrounding communities and supporting the local economy through its hydroelectric operations.
Granby's strategic location and impressive engineering make it a key asset in the sustainable management of water resources and climate resilience efforts in Colorado. As a significant contributor to the local water supply and energy production, Granby stands as a testament to the importance of infrastructure maintenance and monitoring to ensure the safety and reliability of critical water infrastructure in the face of changing environmental conditions.
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 Granby -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Colorado River Below Lake Granby | 108 cfs | → |
| Colorado River Near Granby | 77 cfs | → |
| Willow Creek Below Willow Creek Reservoir | 7 cfs | → |
| Colorado River Bl Shadow Mountain Reservoir | 117 cfs | → |
| Grand Lake Outlet Blw Chipmunk Ln At Grand Lk | 114 cfs | → |
| Colorado River At Windy Gap | 152 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Granby.
Boat launches
- Cr 6 Grand County
- Us 34 Grand County
- Grand County
- Willow Creek Boating Site
- Hilltop Boating Site
- Boat Launch Grand Lake
Campgrounds
Fishing spots
- Granby Lake
- Willow Creek Fishing Site
- Shadow Mountain Reservoir
- Watanga Lake - Ipwa
- Monarch Lake
- Long Lake (Hell Canyon) - Ipwa
Paddle runs
- Headwaters To Ends 0.5 Miles Away From Trail Ridge Road
- Headwaters To Ends 0.5 Miles Upstream From End Of County Hwy 115
- Begins 0.5 Miles Upstream From End Of County Hwy 115 To Eastern Boundary Of Rocky Mountain National Park
- Begins 0.5 Miles Away From Trail Ridge Road To Ends Where River Segment Exits Rocky Mountain National Park
- Headwaters To Ends 0.5 Miles Upstream From End Of Fern Lake Road
- Begins 0.5 Miles Upstream From End Of Fern Lake Road To Eastern Boundary Of Rocky Mountain National Park
Track Granby 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 Granby
Where does the data for Granby 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 Granby.