Cottage Grove Dam dam
Cottage Grove Dam
Cottage Grove Dam, also known as Cottage Grove Lake, is a federally owned structure located on the Coast Fork Willamette River in Oregon. Built in 1942, this earth dam stands at 81 feet tall and serves multiple purposes including flood risk reduction, irrigation, navigation, and recreation. With a storage capacity of 33,000 acre-feet, the dam covers a surface area of 1,158 acres and has a maximum discharge of 40,800 cubic feet per second.
A routine risk assessment conducted in 2012 identified Cottage Grove Dam's risk level as moderate, particularly in the event of an extreme earthquake causing settlement and cracking that could lead to flooding downstream. To address potential risks, the US Army Corps of Engineers (USACE) has implemented risk management measures such as soil sampling, groundwater monitoring, and ongoing inspections. Plans for an advanced risk assessment in 2022, along with the development of an updated Emergency Action Plan, aim to enhance the dam's resilience and reduce risks associated with extreme events.
USACE's commitment to conducting regular risk assessments, implementing interim risk reduction measures, and enhancing community awareness of flood risks underscores its dedication to ensuring the safety and functionality of Cottage Grove Dam. By staying proactive in risk management strategies and engaging with local stakeholders, USACE aims to mitigate potential threats and maintain the dam's critical role in flood risk reduction for 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 Cottage Grove Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Coast Fork Willamette R Blw Cottage Grove Dam | 76 cfs | → |
| Row River Near Cottage Grove | 186 cfs | → |
| Row River Above Pitcher Creek Near | 120 cfs | → |
| Coast Fork Willamette River Near Goshen | 333 cfs | → |
| Middle Fork Willamette River Near Dexter | 2,560 cfs | → |
| Middle Fork Willamette River At Jasper | 2,970 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Cottage Grove Dam.
Boat launches
- Lakeside Park
- Harms Park Row River Trail Access
- Lynx Hollow State Park
- Dexter State Park
- Lowell Park
- Pengra Access
Campgrounds
- Pine Meadows- Cottage Grove Lake
- Primitive - Cottage Grove Lake
- Schwarz
- Baker Bay Park
- Pass Creek County Park
- Sharps Creek Campground
Track Cottage Grove Dam 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 Cottage Grove Dam
Where does the data for Cottage Grove Dam 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 Cottage Grove Dam.