Mayowood Lake Reservoir Report

Last Updated: December 7, 2025

Mayowood Lake, located in Olmsted County, Minnesota, is a gravity dam constructed in 1920 with a primary purpose labeled as "Other." The dam stands at a height of 20 feet and has a structural height of 25 feet, with a length of 140 feet and a storage capacity of 352 acre-feet.


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Summary

The lake covers a surface area of 10 acres and has a drainage area of 147 square miles, with a maximum discharge rate of 5479 cubic feet per second.

Managed by the local government, Mayowood Lake is regulated by the Minnesota Department of Natural Resources, with state permitting, inspection, and enforcement processes in place. The dam has been assessed as having a low hazard potential and satisfactory condition as of the last inspection conducted in June 2017. While no Emergency Action Plan (EAP) details were provided in the data, the lake's risk assessment, inundation maps, and risk management measures are currently unspecified.

Mayowood Lake serves as a vital water resource in the region, with its connection to the Zumbro River South Fork providing important environmental benefits. This reservoir contributes to the overall water management system in the area, showcasing the intersection of water resource management and climate considerations in safeguarding the community against potential risks associated with dam operations.

Year Completed

1920

Dam Length

140

Dam Height

20

River Or Stream

ZUMBRO RIVER SOUTH FORK

Primary Dam Type

Gravity

Surface Area

10

Drainage Area

147

Nid Storage

352

Structural Height

25

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

25
       
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.