Fawn Lake Dam Reservoir Report

Last Updated: December 14, 2025

Fawn Lake Dam, located in Mason County, Washington, was completed in 1966 for the primary purpose of recreation.


°F

°F

mph

Wind

%

Humidity

Summary

This privately owned earth dam stands at a hydraulic height of 36 feet and a structural height of 33 feet, with a length of 240 feet. The dam has a normal storage capacity of 580 acre-feet and a maximum storage capacity of 640 acre-feet, serving as a source of water for the surrounding area.

Managed by the Washington Department of Ecology, Fawn Lake Dam is classified as having a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. The dam overlooks the Tr-Puget Sound river and is situated within the Congressional District 10 of Washington. While the dam has not been modified in recent years, it undergoes regular state inspections, with state jurisdiction, regulation, permitting, and enforcement in place to ensure its safety and compliance with regulations.

Water resource and climate enthusiasts will find Fawn Lake Dam to be an interesting site for its role in providing recreational opportunities and water storage in the region. With its picturesque location and vital function in the local ecosystem, the dam serves as a reminder of the importance of proper dam management and maintenance in the face of changing environmental conditions.

Year Completed

1966

Dam Length

240

River Or Stream

Tr-Puget Sound

Primary Dam Type

Earth

Surface Area

56

Hydraulic Height

36

Drainage Area

0.74

Nid Storage

640

Structural Height

33

Hazard Potential

Low

Foundations

Soil

Nid Height

36
       
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.