Mason dam
Mason
Mason, also known as M-107, is a federal-owned dam located in Baker, Oregon, along the Powder River. Built in 1967 by the Bureau of Reclamation, Mason primarily serves the purpose of flood risk reduction and irrigation. The dam stands at an impressive height of 173 feet and has a storage capacity of 111,500 acre-feet, with a normal storage level at 78,500 acre-feet. The dam's high hazard potential underscores the importance of careful monitoring and maintenance.
Managed by the Bureau of Reclamation, Mason's design includes rockfill construction with an arch core type and a rock foundation. The dam spans 895 feet in length and covers a surface area of 2,235 acres, impacting a drainage area of 165 square miles. With a maximum discharge capacity of 1,210 cubic feet per second, Mason plays a crucial role in managing water resources and mitigating flood risks in the region. While the dam's condition assessment is currently not available, its last inspection in September 2020 and high hazard potential highlight the need for continued vigilance and emergency preparedness.
In the event of an emergency, it is essential for stakeholders to ensure that the Emergency Action Plan (EAP) is up to date and meets guidelines for effective response. With its strategic location and significant impact on the surrounding area, Mason's role in flood risk reduction and water management underscores the importance of ongoing monitoring and risk assessment. As a key asset in the region's water resource infrastructure, Mason serves as a testament to the critical role that dams play in safeguarding communities and ecosystems from the impacts of climate change and extreme weather events.
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 Mason -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| John Day R At Blue Mtn Hot Spgs Nr Prairie City | 46 cfs | → |
| John Day River Near John Day | 159 cfs | → |
| North Fork Malheur River At Beulah Or | 1 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Mason.
Boat launches
- Mason Ramp
- Southwest Shore Boat Launch
- Unity Lake State Recreation Site
- Anthony Lakes Boat Launch
- Anthony Lake Campground
- Grande Ronde Boat Launch
Campgrounds
- Union Creek
- Millers Lane
- Millers Lane Campground
- Southwest Shore
- Southwest Shore Campground
- Mccully Forks
Paddle runs
- Headwaters To Confluence With Van Patten Creek
- Eagle Cap Wilderness Boundary To Confluence With Eagle Crek
- Headwaters To Eagle Cap Wilderness Boundary
- North Fork Malheur River
- Indian Cr, S Fk - M8
- Headwaters (Just North Of Confluence Of Mf Five Points Creek) To Wallowa-Whitman Nf Boundary
Track Mason 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 Mason
Where does the data for Mason 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 Mason.