Rossmoor No. 1 dam
Rossmoor No. 1
Rossmoor No. 1 is a hydroelectric dam located in Newport Beach, California, along the Tr San Diego Cr river. Built in 1964, this Earth-type dam stands at a height of 36 feet and has a storage capacity of 43 acre-feet. Its primary purpose is hydroelectric power generation, with additional functions for irrigation and water supply. The dam is state-regulated and inspected, with enforcement measures in place to ensure its safety and compliance with regulations.
Despite its satisfactory condition assessment, Rossmoor No. 1 has a high hazard potential, requiring regular inspections and emergency preparedness measures. The dam's last inspection was conducted in December 2019, with a frequency of once per year. In the event of an emergency, it is crucial to have updated emergency action plans to mitigate risks and protect downstream communities. With its strategic location and vital role in water resource management, Rossmoor No. 1 serves as a key infrastructure for sustainable development and climate resilience 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 Rossmoor No. 1 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Agua Chinon Wash Nr Irvine Ca | · | → |
| Sand Cyn C A Irvine Ca | 0 cfs | → |
| Bonita C A Irvine Ca | 1 cfs | → |
| Arroyo Trabuco A San Juan Capistrano Ca | 2 cfs | → |
| Santa Ana R A Santa Ana Ca | · | → |
| Santiago C A Santa Ana Ca | · | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Rossmoor No. 1.
Boat launches
Campgrounds
- Upper Moro Campground
- Deer Canyon Campground
- Lower Moro Campground
- Crystal Cove State Park - Moro Campground
- Oso Lake Scout Camp
- Oneill Regional Park
Fishing spots
- Laguna Niguel Lake
- Irvine Lake (Santiago Res)
- Santa Ana River Lakes
- Anaheim Lake
- Corona Lake
- Tri-City Park Lake
Paddle runs
- San Mateo Wilderness Boundary To Nf Boundary With Camp Pendleton
- Devil Canyon Tributary To San Mateo Creek
- Santa Margarita River
- Laurel Gulch To Confluence With Mineo Canyon (Se 1/4, Sw 1/4, Sec 17, T2n, R8w)
- Middle Fork - Commanche Campsite To Middle Fork Trailhead
Track Rossmoor No. 1 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 Rossmoor No. 1
Where does the data for Rossmoor No. 1 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 Rossmoor No. 1.