Lake Oshawno Dam Reservoir Report

Last Updated: December 6, 2025

Lake Oshawno Dam, located in Osage, Kansas, is a privately owned structure designed by USDA NRCS and completed in 1959 for flood risk reduction along the Wakarusa River.


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Summary

Standing at 40 feet tall with a length of 455 feet, this earth dam plays a crucial role in water resource management in the region, providing a normal storage capacity of 134 acre-feet and a maximum storage of 310 acre-feet.

Managed by the Kansas Department of Agriculture, the dam is subject to state regulations, inspections, and enforcement to ensure its structural integrity and safety. Despite being assessed as in fair condition with a high hazard potential, the dam has a spillway width of 100 feet and a maximum discharge capacity of 1051 cubic feet per second. Its location in a picturesque area with a surface area of 18 acres also offers recreational opportunities for visitors to enjoy.

With a primary purpose of flood risk reduction, Lake Oshawno Dam serves as a vital infrastructure for protecting the surrounding communities from potential inundation. Its strategic design and ongoing state oversight highlight the importance of sustainable water resource management and climate resilience in the face of changing environmental conditions.

Year Completed

1959

Dam Length

455

Dam Height

36

River Or Stream

WAKARUSA RIVER-TR

Primary Dam Type

Earth

Surface Area

18

Hydraulic Height

38

Drainage Area

0.75

Nid Storage

310

Structural Height

40

Outlet Gates

None

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

40
       
Seasonal Comparison

Weather Forecast

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. 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

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, 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.