Grandfather Falls dam
Grandfather Falls
Grandfather Falls, located in Lincoln, Wisconsin, is a gravity dam completed in 1906 for hydroelectric purposes on the Wisconsin River. With a height of 32 feet and a length of 700 feet, this impressive structure has a storage capacity of 2540 acre-feet and serves as a vital resource for the region. The dam boasts a controlled spillway with a width of 124 feet and is equipped with 7 Tainter (radial) outlet gates to manage water flow effectively.
Managed by a Public Utility, Grandfather Falls is under the jurisdiction of the state of Wisconsin and is regulated by the Federal Energy Regulatory Commission. Despite its high hazard potential, the dam's condition assessment is currently not available, reflecting the need for ongoing monitoring and maintenance. The surrounding area offers recreational opportunities, making it a popular destination for water resource and climate enthusiasts who appreciate the significance of this historic engineering marvel in the heart of Merrill.
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 Grandfather Falls -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Prairie River Near Merrill | 190 cfs | → |
| Wisconsin River At Merrill | 3,620 cfs | → |
| Spirit River At Spirit Falls | 226 cfs | → |
| Rib River At Rib Falls | 713 cfs | → |
| Eau Claire River At Kelly | 253 cfs | → |
| Wisconsin River At Rothschild | 4,880 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Grandfather Falls .
Boat launches
- Purple Loosestrife -- Island In Alexander Lake 0.15mi Se Pine Grove Rd
- Alexander Flowage -- Access
- South Shore Drive Town Of Merrill
- Prairie River -- Launch Site
- Mohawksin Lake -- Access At Near Dean Rd
- State Highway 86 Tomahawk
Campgrounds
- Camp New Wood County Park
- Camp New Wood County Park Campground
- Council Grounds State Park
- Underdown County Park Campground
- Sara Park
- Otter Lake
Paddle runs
- Headwaters To Footbridge
- Footbridge To Forest Road 144
- Forest Road 144 To Forest Road 148
- Forest Road 148 To Forest Road 149
- Forest Road 149 To West Forest Boundary
- North Branch (Sections 19/30 Line) To Unnamed Creek In Sec 4, T37n, R13e
More reservoirs
Track Grandfather Falls 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 Grandfather Falls
Where does the data for Grandfather Falls 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 Grandfather Falls .