Holly Dam dam
Holly Dam
Holly Dam, also known as Stiff's Millpond Dam, is a significant local government-owned structure located in Fenton, Michigan, along the Shiawassee River. Built in 1840, this Earth and Gravity dam stands at a height of 12 feet and stretches 400 feet in length. With a primary purpose of recreation, the dam offers a storage capacity of 555 acre-feet, a normal storage of 430 acre-feet, and a surface area of 90 acres, making it a crucial water resource in the area.
Despite its historical significance and recreational value, Holly Dam is currently assessed as being in poor condition with a significant hazard potential. The dam is regulated and inspected by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE) to ensure public safety. In the event of an emergency, the dam's Emergency Action Plan (EAP) is expected to meet safety guidelines, with risk assessments indicating a very high risk level. With a maximum discharge capacity of 600 cubic feet per second, the dam plays a vital role in flood control and water management in the region.
As a prominent feature in Oakland County, Michigan, Holly Dam serves as both a recreational hub and a critical water resource. Its historical significance, structural design, and storage capacity make it an essential element in the local ecosystem. However, ongoing maintenance and risk management measures are necessary to ensure the safety and longevity of this important dam for 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 Holly Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Huron River At Milford | 73 cfs | → |
| Kearsley Creek Near Davison | 52 cfs | → |
| Huron River Near New Hudson | 105 cfs | → |
| Flint River Near Flint | 614 cfs | → |
| Clinton River At Auburn Hills | 184 cfs | → |
| Farmers Creek Near Lapeer | 27 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Holly Dam.
Boat launches
- Thomas Road Oakland County
- Crotched Lake, (Holly Recreation Area), Oakland County
- Dickinson Lake, (Seven Lakes St Park), Oakland County
- Groveland Boulevard Oakland County
- Valley Lake, (Holly Recreation Area), Oakland County
- Lake Fenton, 845 Acres, Genesee County
Campgrounds
- Seven Lakes State Park
- Group Camping Area 2
- Group Camping Area 3
- Group Camping Area 1
- Group Camping Area 4
- Group Camping Area 5
Fishing spots
Track Holly 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 Holly Dam
Where does the data for Holly 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 Significant 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 Holly Dam.