Mc Donald Subwatershed Site 1 Reservoir Report
Last Updated: December 14, 2025
Mc Donald Subwatershed Site 1 in Woodbury, Iowa is a local government-owned dam designed by USDA NRCS for recreation and flood risk reduction purposes.
°F
°F
mph
Wind
%
Humidity
Summary
Completed in 1985, this earth-type dam stands at 35 feet tall with a length of 354 feet, providing storage of 220 acre-feet and covering a surface area of 12.3 acres. Situated along the TR-Little Sioux River, this dam is regulated by the Iowa DNR and is under state jurisdiction, with permitting, inspection, and enforcement in place to ensure its safety and functionality.
Although the dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment, the risk assessment categorizes it as moderate. The dam's spillway type is uncontrolled, and it has not undergone any modifications in recent years. While the emergency action plan (EAP) status and risk management measures are currently not available, the dam is not under the jurisdiction of the US Army Corps of Engineers. With its strategic location and purposeful design, Mc Donald Subwatershed Site 1 serves as an essential infrastructure for water resource management and climate resilience in the region, contributing to the overall conservation efforts in Iowa.
Year Completed |
1985 |
Dam Length |
354 |
Dam Height |
35 |
River Or Stream |
TR-LITTLE SIOUX RIVER |
Primary Dam Type |
Earth |
Surface Area |
12.3 |
Drainage Area |
0.92 |
Nid Storage |
220 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
35 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
West Fork Ditch At Hornick
|
80cfs |
Maple River At Mapleton
|
323cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Little Sioux River At Correctionville
|
327cfs |
Missouri River At Decatur
|
14900cfs |
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.
Mc Donald Subwatershed Site 1