Lower Long Lake dam
Lower Long Lake
Lower Long Lake, also known as Long Lake No 2 or Campbell Reservoir, is a public utility water supply located in Arvada, Colorado. This earth dam structure, completed in 1939, stands at 19 feet tall and spans 1350 feet in length, with a storage capacity of 409 acre-feet. The reservoir serves as a critical resource for water supply in the region, with a normal storage capacity of 292 acre-feet and a maximum discharge of 330 cubic feet per second.
Despite its importance, Lower Long Lake poses a high hazard potential and has been assessed as unsatisfactory in condition, with a moderate risk level. The dam is regulated by the Colorado Division of Water Resources, which oversees permitting, inspection, and enforcement activities to ensure the safety and integrity of the structure. With its location on Ralston Creek, Lower Long Lake plays a crucial role in water management and climate resilience efforts in Jefferson County, Colorado. Water resource and climate enthusiasts will find this reservoir a key focal point for understanding the intersection of infrastructure, sustainability, and environmental stewardship 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 Long Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Clear Creek At Golden | 115 cfs | → |
| Coal Creek Near Plainview | 1 cfs | → |
| Little Dry Creek At Westminster | 1 cfs | → |
| North Clear Creek Above Mouth Nr Blackhawk | 5 cfs | → |
| Bear Creek At Morrison | 16 cfs | → |
| Big Dry Creek At Westminster | 0 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lower Long Lake.
Boat launches
- Ralston Creek Trail Arvada
- Standley Lake Trail Westminster
- West 69th Avenue 4700, Westminster
- Miramonte Road Boulder County
- Fisherman's Trail Lakewood
- C-470 Trail Lakewood
Campgrounds
- Clear Creek Rv Park
- Tipi Village
- Standley Lake
- Gennessee Ropes Camp Spot
- Rifleman Phillips Group Campground
- Aspen Meadow - Golden Gate Canyon State Park
Fishing spots
- Arvada Reservoir
- Meadow Park Lake
- Ward Road Pond
- Prospect Park Lakes (Wheatridge)
- Standley Lake
- Birdland Lake (Jack B. Tomlinson Park)
Paddle runs
- Golden Whitewater Park
- Tunnel 1 To Golden Whitewater Park
- Upper Clear Creek
- Idledale To Morrison
- Upper South Boulder Creek
More reservoirs
Track Lower Long 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 Lower Long Lake
Where does the data for Lower Long 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 Lower Long Lake.