Lower Derby dam
Lower Derby
Lower Derby, located in Commerce City, Colorado, is a federal-owned irrigation reservoir managed by the US Army Corps of Engineers. Built in 1942, this earth dam structure stands at a height of 20 feet and has a storage capacity of 1230 acre-feet, serving multiple purposes including fish and wildlife habitat, irrigation, and water supply. The reservoir covers an area of 80 acres and has a maximum discharge capacity of 15,500 cubic feet per second.
Despite its age, Lower Derby remains a significant water resource in Adams County, Colorado, with a state-regulated status and regular inspections by the Department of Water Resources. The dam underwent structural modifications in 1990 to ensure its safety and functionality. With its proximity to the Omaha District of the US Army Corps of Engineers, the reservoir plays a crucial role in maintaining water quality and supply for the surrounding area.
Lower Derby's hazard potential is deemed significant, highlighting the importance of proper risk management and emergency preparedness. While the condition assessment is not currently available, the reservoir's inspection frequency is set at four times a year to monitor its structural integrity. With its strategic location and historical significance, Lower Derby continues to be a key asset in water resource management and climate resilience efforts 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 Lower Derby -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| First Cr Bel Buckley Rd | 2 cfs | → |
| First Cr Ab 96th Ave | 1 cfs | → |
| Sand Crk Abv Burlington Ditch Nr Commerce City | 8 cfs | → |
| South Platte R At 64th Ave. Commerce City | 90 cfs | → |
| Clear Creek At Mouth | 3 cfs | → |
| South Platte River At Henderson | 167 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lower Derby.
Boat launches
- Adams County
- Brighton
- West 69th Avenue 4700, Westminster
- Cherry Creek Park Road Centennial
- Standley Lake Trail Westminster
- West Quincy Avenue Denver
Campgrounds
- Cherokee Group Site
- Chief Ouray Group Site
- Arapahoe Group Site
- Cherry Creek State Park
- Standley Lake
- Tipi Village
Fishing spots
- Rocky Mountain Arsenal
- Engineers Lake
- Thornton Gravel Ponds #2 & #3
- Spratt-Platte Lake
- Elaine T. Valente Open Space
- Clear Creek Pond
Paddle runs
- Golden Whitewater Park
- Idledale To Morrison
- Tunnel 1 To Golden Whitewater Park
- Lower Boulder Canyon
- Upper Clear Creek
- Upper South Boulder Creek
More reservoirs
Track Lower Derby 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 Lower Derby
Where does the data for Lower Derby 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 Significant 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 Lower Derby.