Upper Rock Lake Main dam
Upper Rock Lake Main
Upper Rock Lake Main in California is a privately owned dam regulated by the Department of Water Resources (DWR) for the safety of dams. Completed in 1855, this earth dam stands at 17 feet high and serves primarily for hydroelectric purposes. Located in Nevada County, the dam impounds Texas Creek and has a storage capacity of 190 acre-feet, with a surface area of 0.06 square miles and a drainage area of 0.1 square miles.
Despite its low hazard potential, Upper Rock Lake Main is under the oversight of the Federal Energy Regulatory Commission for inspections and regulatory measures. The dam has not been assessed for its current condition, but an Emergency Action Plan (EAP) was last revised in October 2020. With a high risk assessment score of 2, there are likely management measures in place to ensure the safety and integrity of the structure in the event of an emergency.
Water resource and climate enthusiasts interested in the history and details of Upper Rock Lake Main will find its location, design, and operational characteristics intriguing. As a part of the hydroelectric infrastructure in the region, this dam plays a crucial role in water management and energy production, contributing to the overall resilience of the water resource system 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 Upper Rock Lake Main -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Little Truckee R Bl Div Dam Nr Sierraville Ca | 3 cfs | → |
| Independence C Nr Truckee Ca | 16 cfs | → |
| N Yuba R Bl Goodyears Bar Ca | 402 cfs | → |
| Sagehen C Nr Truckee Ca | 8 cfs | → |
| Donner C A Donner Lk Nr Truckee Ca | 10 cfs | → |
| Donner C At Hwy 89 Nr Truckee Ca | 51 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Upper Rock Lake Main .
Boat launches
- Meadow Lake Road Nevada County
- Woodcamp Access Road Nevada County
- Fuller Lake Boating Site
- Henness Pass Road, Sierraville
- Lake Spaulding Road 10260, Nevada City
- Sardine Lake Road 990, Sierra City
Campgrounds
- Lindsey Lake
- Lindsey Lake Campground
- Bowman Campground
- Canyon Creek Campground
- Island Lake Camping Area #3
- Island Lake Camping Area #1
Fishing spots
Paddle runs
- Langs Crossing Bridge To One-Half Mile West Of Confluence With Fall Creek (Boundary Of Nf And Private Land)
- One-Half Mile West Of Confluence With Fall Creek To Confluence With Jefferson Creek
- Generation And Giant Gaps (Tadpole To Colfax-Iowa Hill Road)
- Royal Gorge (Soda Springs To Tadpole Creek)
- Gold Lake Dam To Falls
- Little Jamison Creek Headwaters To State Park
Track Upper Rock Lake Main 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 Upper Rock Lake Main
Where does the data for Upper Rock Lake Main 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 Upper Rock Lake Main .