Winchester Reservoir Report

Last Updated: December 13, 2025

Winchester is a public utility located in the city of Winchester, Oregon, along the North Umpqua River.


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Summary

This dam, with a height of 17 feet and a length of 485 feet, was completed in 1904 for the primary purpose of recreation. The dam has a storage capacity of 700 acre-feet and covers a surface area of 27 acres, serving as a popular spot for outdoor activities.

Despite its recreational benefits, Winchester Dam is classified as having a high hazard potential and is currently in poor condition. The last inspection in July 2021 revealed the dam's deteriorating state, prompting concerns for its structural integrity and safety. With a designated inspection frequency of once per year, ongoing monitoring and maintenance are crucial to mitigate potential risks associated with the dam.

Managed by the Oregon Water Resources Department, Winchester Dam plays a significant role in the local water resource management and climate regulation efforts. As climate change continues to impact water availability and quality, the maintenance and upkeep of dams like Winchester are essential in ensuring the sustainability and resilience of water resources for future generations.

Year Completed

1904

Dam Length

485

Dam Height

17

River Or Stream

North Umpqua River

Primary Dam Type

Other

Surface Area

27

Hydraulic Height

17

Drainage Area

1344

Nid Storage

700

Structural Height

17

Outlet Gates

Slide (sluice gate)

Hazard Potential

High

Nid Height

17
       
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.