Onion Valley dam
Onion Valley
Onion Valley, located in Montrose, Colorado, is a privately owned dam with a primary purpose of irrigation. Completed in 1954, this earth dam stands at a height of 85 feet and has a hydraulic height of 105 feet. With a storage capacity of 10,380 acre-feet, the dam serves to regulate water from Iron Creek for agricultural use in the region.
The dam has a surface area of 340 acres and a drainage area of 22 square miles, with a maximum discharge capacity of 502 cubic feet per second. Despite its fair condition assessment, Onion Valley is classified as having a high hazard potential. The dam's spillway type is listed as 'None', with outlet gates consisting of a slide (sluice gate) and uncontrolled mechanisms.
Although the dam is not under the jurisdiction of the US Army Corps of Engineers, it is subject to state regulation and enforcement. With its strategic location and critical role in providing water for irrigation, Onion Valley is a significant structure that contributes to the water resource management in the region.
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 Onion Valley -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Gunnison River Below Gunnison Tunnel | 303 cfs | → |
| Smith Fork Near Lazear | 1 cfs | → |
| Cimarron River Bl Squaw Creek | 55 cfs | → |
| N.F. Gunnison R Blw Leroux Cr | 774 cfs | → |
| North Fork Gunnison River Below Paonia | 49 cfs | → |
| North Fk Gunnison River Above Mouth Nr Lazear | 692 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Onion Valley.
Boat launches
- Chukar Boat Ramp
- Ponderosa Campground Gunnison County
- Gunnison Forks
- Delta County
- South River Road Delta County
- Grand Avenue Delta County
Campgrounds
- Crawford State Park
- East Portal Campground
- East Portal - Curecanti National Rec Area
- North Rim - Gunnison National Park
- North Rim Campground
- South Rim - Gunnison National Park
Fishing spots
- Gould Reservoir
- Crawford Reservoir
- Crystal Reservoir
- Morrow Point Reservoir
- Chipeta Lakes Swa
- Blue Mesa Reservoir
Paddle runs
- The Southern Boundary Of The Black Canyon Gunnison National Monument To The Painted Wall
- Gunnison Gorge
- The Painted Wall To The Black Canyon Gunnison National Monument-Gunnison Gorge Wilderness Boundary
- Curecanti National Recreation Area Boundary To High Water Line Of Morrow Point Reservoir
- Curecanti National Recreation Area Boundary To High Water Line Of Blue Mesa Reservoir
More reservoirs
Track Onion Valley 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 Onion Valley
Where does the data for Onion Valley 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 Onion Valley.