Sinlahekin Dam No 2 dam
Sinlahekin Dam No 2
Sinlahekin Dam No 2, also known as Reflection Pond, is a state-owned earth dam located in Loomis, Washington, along Sinlahekin Creek. Designed by URS-Woodward Clyde and completed in 1949, this dam serves primarily for recreational purposes, offering a serene setting for outdoor enthusiasts to enjoy. With a structural height of 18 feet and a storage capacity of 82 acre-feet, Sinlahekin Dam No 2 provides essential water resources for the surrounding area while also creating a picturesque surface area of 10 acres.
Despite its fair condition assessment and high hazard potential, Sinlahekin Dam No 2 is regulated, permitted, inspected, and enforced by the Washington Department of Ecology, ensuring the safety and integrity of the structure. The dam's location within Okanogan County, Washington, showcases its importance in managing water resources and protecting against potential risks. With its proximity to Sinlahekin Creek and a drainage area of 64 square miles, this dam plays a crucial role in preserving the natural environment and supporting the local ecosystem.
Managed by the state and situated in Congressional District 04, Washington, Sinlahekin Dam No 2 stands as a testament to the intersection of water resource management and climate resilience. Its design, construction, and ongoing maintenance highlight the collaboration between government agencies and engineering firms to safeguard vital infrastructure and promote sustainable recreational opportunities. As enthusiasts of water resources and climate adaptation, the significance of Sinlahekin Dam No 2 cannot be understated in ensuring the well-being of both the community and the environment.
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 Sinlahekin Dam No 2 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Okanogan River Near Tonasket | 5,120 cfs | → |
| Similkameen River Near Nighthawk | 4,950 cfs | → |
| Okanogan River At Oroville | 164 cfs | → |
| Andrews Creek Near Mazama | 107 cfs | → |
| Omak Creek Near Omak | 3 cfs | → |
| Methow River At Winthrop | 2,740 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Sinlahekin Dam No 2.
Boat launches
- Sinlahekin Road Okanogan County
- Windy Flat Road Okanogan County
- South Fish Lake Road, Okanogan
- Split Rock
- Loomis-Oroville Road 1667, Loomis
- Loomis-Oroville Road 322, Tonasket
Campgrounds
- Forde Lake
- Forde Lake - Wdfw
- Sinlahekin Wildlife Area
- Conners Lake
- Conners Lake - Wdfw
- Sinlahekin Creek - Wdfw
Track Sinlahekin Dam No 2 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 Sinlahekin Dam No 2
Where does the data for Sinlahekin Dam No 2 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 Sinlahekin Dam No 2.