Winnewana Dam dam
Winnewana Dam
Winnewana Dam, located in the Sugarloaf Lake Resort Area in Washtenaw, Michigan, is a state-regulated earth dam completed in 1956 primarily for recreational purposes. Standing at a height of 12 feet with a hydraulic height of 10 feet, this dam boasts a length of 270 feet and a normal storage capacity of 1000 acre-feet. The dam's significant hazard potential and fair condition assessment make it a crucial structure to monitor and maintain.
Managed by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE), Winnewana Dam plays a vital role in the local water resource management system as it controls water flow in a tributary to the Portage River. Despite its uncontrolled spillway type and moderate risk assessment, the dam has not undergone major modifications in recent years. Regular inspections every four years ensure that the dam continues to meet safety standards and operational requirements, with the last inspection conducted in June 2017.
With its picturesque location and essential function in the region's water infrastructure, Winnewana Dam serves as both a recreational hotspot and a critical component of flood control measures. As climate change continues to impact water resources, the ongoing monitoring and maintenance of this dam are essential to safeguarding the surrounding community and ecosystems.
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 Winnewana Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mill Creek Near Dexter | 42 cfs | → |
| River Raisin Near Manchester | 23 cfs | → |
| Grand River At Jackson | 87 cfs | → |
| Huron River Near Hamburg | 205 cfs | → |
| Huron River At Ann Arbor | 313 cfs | → |
| Malletts Creek At Ann Arbor | 3 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Winnewana Dam.
Boat launches
- Roe Road 8353, Lyndon Township
- Cedar Lyndon Township
- Loveland Road Waterloo Village
- Mcclure Road Sylvan Township
- Loveland Road Sylvan Township
- Cemetery Drive Sylvan Township
Campgrounds
- Sugarloaf Lake - Waterloo State Rec Area
- Burns Cabins
- Horsemen's Equestrian Campground
- Green Lake - Waterloo State Rec Area
- Green Lake Rustic Campground
- Menominee
Track Winnewana 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 Winnewana Dam
Where does the data for Winnewana 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 Winnewana Dam.