Rainbow Lake dam
Rainbow Lake
Rainbow Lake in Larimer, Colorado, is a private earth dam completed in 2016 with a primary purpose of water supply. Located in Pinewood Springs, this dam on the West Fork Little Thompson River has a height of 16 feet and a length of 300 feet, providing a storage capacity of 69 acre-feet. While its hazard potential is rated as low, the risk assessment indicates a moderate level of risk.
This picturesque reservoir covers 7 acres and offers recreational opportunities in addition to its water supply function. Designed by GEI and Nick Miller, Rainbow Lake is regulated by the Colorado Division of Water Resources, with permitting, inspection, and enforcement carried out by state authorities. Despite its relatively small size, the dam serves a vital role in the local water management system, ensuring a stable supply for the surrounding community.
Water resource and climate enthusiasts will appreciate Rainbow Lake as a well-maintained and regulated structure that contributes to water supply and recreation in the area. With its low hazard potential and moderate risk assessment, this earth dam represents a balanced approach to water management, emphasizing safety and sustainability. Its location in the scenic Colorado landscape adds to its charm, making it a noteworthy site for those interested in the intersection of water resources and environmental conservation.
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 Rainbow Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. Vrain Creek At Lyons | 89 cfs | → |
| Left Hand Creek Near Boulder | 36 cfs | → |
| South St. Vrain Creek Near Ward | 37 cfs | → |
| Fourmile Creek At Orodell | 2 cfs | → |
| Buckhorn Creek Near Masonville | 21 cfs | → |
| Left Hand Creek At Hover Road Near Longmont | 1 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Rainbow Lake.
Boat launches
- Lagerman Trail Boulder County
- Boat Launch Grand Lake
- Hilltop Boating Site
- Grand County
- Miramonte Road Boulder County
- Boat Ramp Larimer County
Campgrounds
- Hermit Park Open Space
- Meeker Park Overflow Campground
- Meeker Park Overflow
- Olive Ridge Campground
- Olive Ridge
- Meadow Mountain Ranch
Fishing spots
- Ralph Price Reservoir (Button Rock)
- Copeland Lake - Rmnp
- Lily Lake - Rmnp
- South Saint Vrain Fishing Site #2
- South Saint Vrain Fishing Site #5
- South Saint Vrain Fishing Site #4
Track Rainbow Lake 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 Rainbow Lake
Where does the data for Rainbow Lake 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 Rainbow Lake.