Hillman dam
Hillman
Located in Montmorency County, Michigan, Hillman is a hydroelectric dam on the Thunder Bay River that was completed in 1895. With a dam height of 16 feet and a length of 128 feet, Hillman serves multiple purposes including hydroelectric power generation and recreation. The dam has a storage capacity of 500 acre-feet and covers a surface area of 160 acres, with a maximum discharge of 2100 cubic feet per second.
Managed by the Federal Energy Regulatory Commission, Hillman has a low hazard potential and a moderate risk assessment rating. It features an uncontrolled spillway with a width of 45 feet and three slide (sluice gate) outlet gates. While the condition assessment is currently not available, the dam undergoes inspections every three years to ensure its safety and integrity. In the event of an emergency, an Emergency Action Plan (EAP) is in place, last revised in December 2019.
Hillman Dam represents a blend of historical significance and modern-day functionality, contributing to water resource management and renewable energy generation in the region. Its presence on the Thunder Bay River not only provides economic benefits through hydroelectric power production but also offers recreational opportunities for visitors. As climate change continues to impact water resources, the maintenance and monitoring of dams like Hillman become crucial for sustainable water management and climate resilience efforts.
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 Hillman -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Thunder Bay River At Herron Road Near Bolton | 764 cfs | → |
| Pigeon R At Sturgeon Valley Rd Near Vanderbilt | 135 cfs | → |
| Au Sable River At Mio | 1,320 cfs | → |
| Au Sable River Near Mc Kinley | 1,680 cfs | → |
| Au Sable River Near Red Oak | 1,410 cfs | → |
| Au Sable River Near Curtisville | 1,550 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Hillman .
Boat launches
- Lake Avalon Boating Access Site Hillman Township
- Grass Lake Road Montmorency Township
- Iafrate Drive Montmorency Township
- County Road 634 Bismarck Township
- West Highway 9330, Bismarck Township
- Clear Lake State Park Boating Access Site Montmorency Township
Campgrounds
- Ess Lake State Forest Campground
- Jackson Lake State Forest Campground
- Avery Lake State Forest Campground
- Tomahawk Lake State Forest Campground
- Mccollum Lake State Forest Campground
- Town Corner Lake State Forest Campground
Fishing spots
Track Hillman 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 Hillman
Where does the data for Hillman 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 Low 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 Hillman .