Lewis Dam Reservoir Report

Last Updated: December 15, 2025

Lewis Dam, located in Kitsap, Washington, is a privately owned structure that serves primarily for recreational purposes.


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Summary

Completed in 1973, this earth dam stands at a hydraulic height of 15 feet with a structural height of 12 feet and a length of 120 feet. The dam has a storage capacity of 330 acre-feet, with a normal storage level of 300 acre-feet and a surface area of 300 acres. It is situated on Tr-Big Beef Creek and falls under the regulatory jurisdiction of the Washington Department of Ecology.

With a low hazard potential and a condition assessment that is not rated, Lewis Dam is a relatively stable structure that has not undergone recent modifications. It does not have an Emergency Action Plan (EAP) prepared, and its last inspection date and inspection frequency are unknown. The dam is not owned or funded by any federal agency and has no associated locks, spillways, or outlet gates. While it does not currently pose a significant risk, ongoing monitoring and maintenance may be necessary to ensure its continued safety and functionality for recreational purposes in the future.

Year Completed

1973

Dam Length

120

River Or Stream

Tr-Big Beef Creek

Primary Dam Type

Earth

Surface Area

300

Hydraulic Height

15

Drainage Area

14

Nid Storage

330

Structural Height

12

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

15
       
Seasonal Comparison

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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.