Otranto Dam Reservoir Report
Nearby: St Ansgar Milldam Staceyville Dam
Last Updated: December 13, 2025
Located in St.
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Summary
Ansgar, Iowa, the Otranto Dam is a gravity-type structure built in 1902 for recreational purposes along the Cedar River. With a height of 7 feet and a length of 170 feet, the dam provides a storage capacity of 168 acre-feet and covers a surface area of 48 acres. Despite its low hazard potential, the dam is regulated by the Iowa Department of Natural Resources and undergoes regular inspections, permitting, and enforcement to ensure its safety and compliance with state regulations.
The Otranto Dam is situated in Mitchell County, Iowa, under the jurisdiction of the Rock Island District of the US Army Corps of Engineers. While it has not been modified in recent years and its condition remains unrated, the dam poses a moderate risk, prompting the need for ongoing risk assessment and management measures. The dam features an uncontrolled spillway and is surrounded by a drainage area of 656 square miles. As a key recreational attraction in the area, the dam serves as a vital water resource for the community while offering opportunities for outdoor activities and enjoyment.
Despite its age, the Otranto Dam continues to be a significant landmark in the region, providing both recreational benefits and essential water storage capacity. With its historical significance and environmental impact on the Cedar River, the dam underscores the importance of sustainable water resource management and climate resilience efforts in the face of changing weather patterns and increasing risks associated with dam safety.
Year Completed |
1902 |
Dam Length |
170 |
Dam Height |
7 |
River Or Stream |
CEDAR RIVER |
Primary Dam Type |
Gravity |
Surface Area |
48 |
Drainage Area |
656 |
Nid Storage |
168 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
7 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Cedar River Near Austin
|
117cfs |
Winnebago River At Mason City
|
166cfs |
Cedar River At Charles City
|
450cfs |
Little Cedar River Near Ionia
|
70cfs |
South Fork Zumbro River At Rochester
|
85cfs |
Root River Near Pilot Mound
|
303cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
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. Investigations and studies are necessary.
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.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams 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, environment 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.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Otranto County Park Campground
|
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Halvorson County Park Campground
|
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Riverside County Park Campground
|
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Interstate County Park Campground
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Otranto Dam