Harper Lake dam
Harper Lake
Harper Lake, located in Boulder, Colorado, is a vital water source managed by the local government for water supply purposes. This Earth dam, completed in 1985, stands at a height of 11 feet and has a storage capacity of 843 acre-feet, with a normal storage level of 715 acre-feet. The lake covers a surface area of 31 acres and is fed by Coal Creek-TR, providing essential resources for the surrounding area.
Despite its small size, Harper Lake plays a crucial role in the region's water management, with a maximum discharge capacity of 460 cubic feet per second and an uncontrolled spillway width of 8 feet. The dam has a satisfactory condition assessment as of September 2020, with a high hazard potential due to its location. The emergency action plan is in place, but its last revision was in 2018, necessitating regular updates to ensure preparedness for any potential risks or emergencies that may arise.
Harper Lake serves as a prime example of efficient water resource management in Colorado, highlighting the importance of monitoring and maintaining infrastructure to ensure the safety and sustainability of water supplies in the face of changing climate conditions. The dedication of local government agencies, in conjunction with regulatory oversight from the state, underscores the commitment to safeguarding this valuable resource for future generations of residents and wildlife in the area.
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 Harper Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Boulder Cr At North 75th St Nr Boulder | 37 cfs | → |
| Big Dry Creek At Westminster | 1 cfs | → |
| Fourmile Creek At Orodell | 2 cfs | → |
| Boulder Creek Near Orodell | 63 cfs | → |
| Coal Creek Near Plainview | 1 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 Harper Lake.
Boat launches
- Standley Lake Trail Westminster
- Lagerman Trail Boulder County
- Ralston Creek Trail Arvada
- Miramonte Road Boulder County
- West 69th Avenue 4700, Westminster
- Brighton
Campgrounds
Fishing spots
- Harper Lake
- Louisville (Warembourg) Fishing Pond
- Teller Lake No. 3
- Waneka Lake
- Boulder Ponds
- Stearns Lake
Track Harper 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 Harper Lake
Where does the data for Harper 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 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 Harper Lake.