St Ansgar Milldam dam
St Ansgar Milldam
St Ansgar Milldam, located in Mitchell, Iowa, along the Cedar River, is a historic gravity dam completed in 1919 primarily for recreation purposes. The dam stands at a height of 9 feet and spans 202 feet, with a storage capacity of 600 acre-feet and a drainage area of 780 acres. Despite being categorized as having a low hazard potential, the dam is subject to state regulation and inspection by the Iowa DNR to ensure its safety and integrity.
While the dam does not have a spillway, it is equipped with uncontrolled spillway type to manage water flow during high water events. The risk assessment for St Ansgar Milldam is moderate, indicating a level 3 risk, with no specific risk management measures or emergency action plan currently in place. The dam's condition assessment is listed as "Not Rated", highlighting the need for further evaluation and potential improvements to enhance its safety and resilience in the face of changing climate conditions and increasing water resource challenges.
Overall, St Ansgar Milldam serves as both a recreational and structural asset in the community, offering opportunities for outdoor activities and water-based recreation. As climate change continues to impact water resources and infrastructure, ongoing monitoring and maintenance of the dam will be crucial to ensure its continued function and safety for the surrounding area. Enthusiasts of water resources and climate adaptation will find St Ansgar Milldam to be an intriguing case study in the intersection of historical preservation, recreational use, and the evolving challenges of climate resilience in dam management.
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 St Ansgar Milldam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Cedar River Near Austin | 158 cfs | → |
| Winnebago River At Mason City | 338 cfs | → |
| Cedar River At Charles City | 531 cfs | → |
| Little Cedar River Near Ionia | 232 cfs | → |
| Shell Rock River At Shell Rock | 1,240 cfs | → |
| Cedar River At Waverly | 1,650 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near St Ansgar Milldam.
Boat launches
- Oakland Place Northeast Austin
- Wapsi Great Western Line Mitchell County
- Big Blue Loop Mason City
- South Pierce Avenue Mason City
- Finch Avenue Worth County
- Howard County
Campgrounds
- Halvorson County Park Campground
- Otranto County Park Campground
- Interstate County Park Campground
- Riverside County Park Campground
- Osage Sprink Park Campground
- Pioneer County Park
Track St Ansgar Milldam 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 St Ansgar Milldam
Where does the data for St Ansgar Milldam 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 St Ansgar Milldam.