Mainline 3 Reservoir Report

Last Updated: December 6, 2025

Mainline 3, also known as Cemetery Canyon Dam, is a privately owned structure located in Crook, Oregon.


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Summary

Built in 1971, this earth dam stands at 42 feet high and spans 200 feet in length, with a storage capacity of 350 acre-feet for irrigation purposes on Cemetery Creek. The dam's maximum discharge rate is 67 cubic feet per second, with a significant hazard potential due to its condition being not rated.

The dam is regulated by the Oregon Water Resources Department and undergoes regular inspections, with the last one conducted in February 2020. Despite its age, Mainline 3 continues to serve its primary purpose of irrigation effectively, with a normal storage capacity of 168 acre-feet and a surface area of 12 acres. The structure is equipped with a slide gate outlet for water release, ensuring controlled management of water levels in the reservoir. Overall, Mainline 3 plays a vital role in supporting agricultural activities in the region and highlights the importance of proper dam maintenance and monitoring in the face of changing climate conditions.

Year Completed

1971

Dam Length

200

Dam Height

37

River Or Stream

CEMETERY CREEK

Primary Dam Type

Earth

Surface Area

12

Hydraulic Height

40

Drainage Area

1

Nid Storage

350

Structural Height

42

Outlet Gates

Slide (sluice gate)

Hazard Potential

Significant

Nid Height

42
       
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.