Long Lake dam
Long Lake
Long Lake, located in Graeagle, California, is a privately owned reservoir on Gray Eagle Creek with a primary purpose of water supply for irrigation and other uses. The dam, completed in 1938, is a rockfill structure standing at 12 feet high and holding a storage capacity of 1478 acre-feet. With a surface area of 141 acres and a drainage area of 1.13 square miles, Long Lake provides essential water resources for the surrounding area.
Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Long Lake is regulated, permitted, inspected, and enforced to ensure its structural integrity and safety. The dam is classified as having a significant hazard potential but is currently assessed as being in satisfactory condition as of September 2017. The last inspection in October 2020 indicated that the dam meets guidelines and emergency preparedness measures are in place.
Water resource and climate enthusiasts visiting Long Lake can appreciate the engineering feat of the rockfill dam, the serene beauty of the reservoir, and the vital role it plays in providing water for irrigation and other needs in the Plumas County area. As a well-regulated and maintained water source, Long Lake is a testament to the importance of sustainable water management practices in the face of changing environmental conditions.
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 Long Lake -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| N Yuba R Bl Goodyears Bar Ca | 459 cfs | → |
| Spanish C A Quincy Ca | 54 cfs | → |
| Little Truckee R Bl Div Dam Nr Sierraville Ca | 3 cfs | → |
| Spanish C Ab Blackhawk C At Keddie Ca | 116 cfs | → |
| Independence C Nr Truckee Ca | 15 cfs | → |
| Sagehen C Nr Truckee Ca | 9 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Long Lake.
Boat launches
- Salmon Lake -Boat Ramp Boating Site
- Salmon Lake Road 1500, Sierra City
- Sardine Lake Road 990, Sierra City
- Smokey Lane 44-50, Alleghany
- Plumas County
- Henness Pass Road, Sierraville
Campgrounds
- Lakes Basin Group Campground
- Lakes Basin Campground
- Lakes Basin .
- Gold Lake 4x4
- Gold Lake 4x4 Campground
- Haven Lake Campground
Fishing spots
Paddle runs
- Gold Lake Dam To Falls
- Little Jamison Creek Headwaters To State Park
- Headwaters To State Park
- Falls To Gold Lake Highway
- Gold Lake Highway To Nf Boundary
- Headwaters Of North Fork Canyon Creek (Sec 6, T21n, R11e) To Confluence With East Fork Canyon Creek
More reservoirs
Track 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 Long Lake
Where does the data for 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 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 Long Lake.