Little Gem dam
Little Gem
Little Gem is a private irrigation dam located in Weld County, Colorado, along the St. Vrain Creek. Built in 1902 by TH Engineering, this earth dam stands at a height of 27 feet and has a storage capacity of 175 acre-feet. With a surface area of 12 acres, the dam serves the primary purpose of irrigation, providing water for agricultural use in the region.
Despite being classified as having a low hazard potential, Little Gem is subject to state regulation and inspection by the Colorado Division of Water Resources. The dam has a spillway width of 30 feet and a maximum discharge capacity of 967 cubic feet per second. While its condition assessment is not rated, the risk assessment for the dam is considered moderate. With a history dating back over a century, Little Gem continues to play a vital role in water resource management in the area.
The dam's location in Gilcrest, Colorado, highlights its importance in the local water infrastructure. As a key structure along the St. Vrain Creek, Little Gem contributes to the overall water management system in the region. With its historical significance, structural features, and regulatory oversight, Little Gem stands as a testament to the ongoing efforts to ensure the safety and sustainability of water resources in Weld County.
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 Little Gem -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. Vrain Creek At Mouth | 88 cfs | → |
| St Vrain Cr Blw Boulder Cr At Hwy 119 Nr Longmont | 82 cfs | → |
| St. Vrain Creek Below Longmont | -999,999 cfs | → |
| Boulder Creek At Mouth | 7 cfs | → |
| Big Thompson River At Loveland | 80 cfs | → |
| Big Thompson River At Mouth | 38 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Little Gem.
Boat launches
- Lagerman Trail Boulder County
- Boat Ramp Larimer County
- Brighton
- Adams County
- Standley Lake Trail Westminster
Campgrounds
- St. Vrain State Park
- Union Reservoir
- Missile Site Park
- Boulder County Fairground
- Boyd Lake State Park
- Carter Lake - South Side Campgrounds
Fishing spots
- Mead Ponds
- Johnstown Reservoir
- Ehrlich Lake
- St. Vrain State Park (Barbour Ponds)
- Union Reservoir
- Roberts Lake
Paddle runs
- October Hole
- Black Bear Hole & A-Hole
- Ssv - Confluence To Picnic Grounds
- Main Section
- Gnar Section
- Lower Boulder Canyon
More reservoirs
Track Little Gem 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 Little Gem
Where does the data for Little Gem 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 Low 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 Little Gem.