San Marcos dam
San Marcos
Located in San Diego, California, the San Marcos dam stands as a vital water supply structure in the region. Built in 1958, this earth dam spans 400 feet in length and reaches a height of 85 feet, with a storage capacity of 320 acre-feet. Serving multiple purposes including irrigation and water supply, the dam is situated on the Tr San Marcos Creek, contributing to the overall water management system in the area.
Managed by a public utility, the San Marcos dam is regulated by the Department of Water Resources (DWR) and falls under the Safety of Dams jurisdiction. With a high hazard potential but currently deemed to be in satisfactory condition, the dam undergoes regular inspections and enforcement measures to ensure the safety and functionality of the structure. The last assessment in September 2017 confirmed its sound state, providing assurance to the surrounding community in Los Vallecitos.
Despite its age, the San Marcos dam continues to play a crucial role in water resource management in the region, with a close eye on its maintenance and emergency preparedness. As a key component in the water supply infrastructure, the dam serves as a reminder of the importance of sustainable water management practices, particularly in the face of changing climate patterns and increasing water demands.
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 San Marcos -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Los Penasquitos C Nr Poway Ca | 3 cfs | → |
| Guejito C Nr San Pasqual Ca | 0 cfs | → |
| San Luis Rey R A Oceanside Ca | 2 cfs | → |
| Santa Maria C Nr Ramona Ca | · | → |
| Santa Margarita R A Ysidora Ca | · | → |
| Oneill Lake Outlet Ch Nr Fallbrook Ca | 0 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near San Marcos.
Boat launches
- Lake Hodges Boat Launching Area
- Lake Miramar
- Sutherland Dam Road 21568-21722, Ramona
- Shore Drive San Diego
- Mission Bay Drive San Diego
Campgrounds
- Group Camp Site
- Dixon Lake
- South Carlsbad State Beach
- San Elijo State Beach
- Guajome Park
- Broken Rock Ranch
Fishing spots
Paddle runs
- Santa Margarita River
- Confluence Of Fry And Iron Spring Creeks (E1/2, Sec 3, T10s,R1e To Se1/4 Sec 16, T10s, R2e
- Forest Boundary, Above Zoo Creek Below Spillway (S1/2, Sec 3, T11s, R2e) To La Jolla Indian Reservation Boundary (N1/2, Sec 31, T10s, R2e)
- Devil Canyon Tributary To San Mateo Creek
- San Mateo Wilderness Boundary To Nf Boundary With Camp Pendleton
Track San Marcos 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 San Marcos
Where does the data for San Marcos 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 San Marcos.