Angus-Oslo 4 Reservoir Report
Last Updated: December 5, 2025
Located in Angus, Minnesota, the Angus-Oslo 4 dam is a vital structure designed for flood risk reduction along the Red River-TR.
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Summary
Completed in 2000, this earth dam stands at a height of 22 feet with a hydraulic height of 18 feet, serving as a crucial defense against potential flooding in the region. With a storage capacity of 8,068 acre-feet and a surface area of 960 acres, the dam plays a pivotal role in managing water flow and mitigating flood risks in Polk County.
Managed by the Minnesota Department of Natural Resources, the Angus-Oslo 4 dam is subject to regular inspections and maintenance to ensure its structural integrity and functionality. Classified as having a low hazard potential and a satisfactory condition assessment, the dam is equipped with an uncontrolled spillway with a width of 4,800 feet to manage excess water discharge effectively. Despite its moderate risk assessment rating, the dam continues to be a reliable asset in the local government's efforts to protect the community from potential flooding events.
As a key component of the flood risk reduction infrastructure in Minnesota, the Angus-Oslo 4 dam stands as a testament to effective water resource management and climate resilience. With its strategic location and design, this earth dam serves as a critical barrier against flooding along the Red River-TR, safeguarding the surrounding areas and populations from the impacts of extreme weather events. Through regular oversight and maintenance, the dam remains a valuable asset in the state's efforts to enhance water security and adapt to changing climate conditions.
Year Completed |
2000 |
Dam Length |
26400 |
Dam Height |
22 |
River Or Stream |
RED RIVER-TR |
Primary Dam Type |
Earth |
Surface Area |
960 |
Hydraulic Height |
18 |
Drainage Area |
23 |
Nid Storage |
8068 |
Structural Height |
22 |
Hazard Potential |
Low |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Thief River Near Thief River Falls
|
45cfs |
Clearwater River At Red Lake Falls
|
98cfs |
Middle River At Argyle
|
10cfs |
Red Lake River At Crookston
|
403cfs |
Red Lake River At Fisher
|
596cfs |
Cyr Creek Near Marcoux Corners
|
42cfs |
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.
Angus-Oslo 4