Siltcoos Lake Reservoir Report

Last Updated: December 15, 2025

Siltcoos Lake in Oregon is a privately-owned reservoir with a gravity dam completed in 1964 for various purposes.


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Summary

The dam stands at 14 feet high and stretches 130 feet in length, holding a maximum storage capacity of 15,070 acre-feet of water. With a surface area of 3,585 acres and a drainage area of 50 square miles, Siltcoos Lake plays a crucial role in water resource management in the region.

Managed by the state regulatory agency OWRD, Siltcoos Lake has a low hazard potential and is inspected every 6 years for safety. The dam features slide gates for water release and is situated along the Siltcoos River, with no downstream settlements to worry about in case of emergencies. Despite not being currently rated for condition assessment, the lake continues to provide vital water resources and recreational opportunities for enthusiasts and climate advocates alike.

With a notable presence in a pristine natural setting, Siltcoos Lake offers a glimpse into the delicate balance between water resource management and environmental conservation. As climate change continues to impact water availability and quality, this reservoir serves as a valuable asset in understanding and adapting to the challenges ahead. From its historical construction to its current state of regulation, Siltcoos Lake remains a focal point for water enthusiasts and climate activists seeking to protect and preserve our vital natural resources.

Year Completed

1964

Dam Length

130

Dam Height

12

River Or Stream

SILTCOOS RIVER

Primary Dam Type

Gravity

Surface Area

3585

Hydraulic Height

12

Drainage Area

50

Nid Storage

15070

Structural Height

14

Outlet Gates

Slide (sluice gate)

Hazard Potential

Low

Nid Height

14
       
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.